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Article

Investigation of Chemical Constituents and Antioxidant Activity of Biologically Active Plant-Derived Natural Products

by
Katarzyna Godlewska
1,*,
Paweł Pacyga
2,
Agnieszka Najda
3 and
Izabela Michalak
4
1
Department of Pharmacology and Toxicology, The Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, 50-375 Wrocław, Poland
2
Department of Thermodynamics and Renewable Energy Sources, Faculty of Mechanical and Power Engineering, Wrocław University of Science and Technology, 50-370 Wrocław, Poland
3
Department of Vegetable and Herbal Crops, The University of Life Science in Lublin, 20-950 Lublin, Poland
4
Department of Advanced Material Technologies, Faculty of Chemistry, Wrocław University of Science and Technology, 50-372 Wrocław, Poland
*
Author to whom correspondence should be addressed.
Molecules 2023, 28(14), 5572; https://doi.org/10.3390/molecules28145572
Submission received: 14 June 2023 / Revised: 11 July 2023 / Accepted: 17 July 2023 / Published: 21 July 2023
(This article belongs to the Special Issue Bioactive Compounds and Antioxidant Activity of Extracts from Different Natural Plants)
Versions Notes

Abstract

:
The aim of this publication is to present rapid screening methods (visual/colorimetric) that will enable quick identification of the presence of biologically active compounds in aqueous solutions. For this reason, 26 plant extracts obtained by ultrasound-assisted extraction were analysed for the content of these compounds. Higher plants, used as a raw material for extraction, are common in Europe and are easily available. The article proposes a comparison of various protocols for the identification of various compounds, e.g., phenolic compounds (phenols, tannins, anthocyanins, coumarins, flavones, flavonoids), vitamin C, quinones, quinines, resins, glycosides, sugars. Initial characterisation of the composition of plant extracts using fast and inexpensive methods allows you to avoid the use of time-consuming analyses with the use of advanced research equipment. In addition, the antioxidant activity of plant extracts using spectrophotometric methods (DPPH, ABTS, FRAP assay) and quantitative analysis of plant hormones such as abscisic acid, benzoic acid, gibberellic acid, indole acetic acid, jasmonic acid, salicylic acid, zeatin, zeatin riboside, and isipentenyl adenine was performed. The obtained results prove that the applied visual methods show different sensitivity in detecting the sought chemical compounds. Therefore, it is necessary to confirm the presence or absence of bioactive substances and their concentration using modern analytical methods.

1. Introduction

Plants were used as a primary raw material for medical therapies until the invention of synthetic drugs in the 19th century [1,2,3,4,5]. Plants are a notable source of natural chemicals, with various structural and biological features that exhibit multifarious mechanisms of action [6,7,8]. The various plant species contain myriad secondary metabolites (substances produced by cells through the metabolic pathway) that greatly influence their competitiveness in the environment and protection against adverse growth conditions [7,9,10,11]. These substances are also known to exhibit a great value for humans [8,12]. The plant-based bioactive compounds can be classified according to biological pathways and chemical classes, among which main chemical groups can be distinguished, such as: alkaloids, furanocoumarins, glycosides (anthraquinone glycosides, cardiac glycosides, cyanogenic glycosides, glucosinolates, and saponins), lignans, naphthodianthrones, peptides, phenolic compounds (anthocyanins, flavonoids, hydroxycinnamic and phenolic acids, and stilbenes), phenylpropanoids, proteins, tannins (condensed tannins—polymers of flavonoids, hydrolysable tannins—polymers of a monosaccharide core with several catechin derivatives attached), mono-, di-, and sesquiterpenoids, and resins [2,6,9,11,12,13,14,15]. In particular, the development of natural products containing substances isolated from natural origin has increased in recent years due to their high efficacy, safety, and long-term health effects [3,5,12,16,17,18,19]. They have been applied in many fields, including beverages, cosmetics, dyeing, flavouring, fragrances, medicine (e.g., steroids and alkaloids), nutrition and functional foods (e.g., sterols and stanols as cholesterol-lowering ingredients), repellents, smoking, and other industrial purposes [1,8,10,11,12,18,20]. However, to source these valuable components, which can occur in small quantities, it is crucial to employ the appropriate extraction, purification, and separation methods [7,8]. Generally, isolation is carried out in accordance with widely recognised techniques concerning complete extraction (e.g., maceration, steam- or hydro-distillation, pressing, boiling, infusion, percolation, Soxhlet extraction, microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), accelerated solvent extraction (ASE), supercritical fluid extraction (SFE), pressurised fluid extraction (PFE), enzyme-assisted extraction (EAE), subcritical water extraction (SWE), ionic liquid extraction (ILE), pulse electric field extraction (PEFE)), preferably with nontoxic solvents (e.g., water, carbon dioxide, ethanol, ionic liquids) [7,8,10,11,12,19,20,21,22]. The biomass extract preparation includes general pre-treatment (e.g., liquid-liquid extraction, solid-phase extraction, gel filtration) and pre-concentration (e.g., gel filtration, solid-phase extraction, molecularly imprinted polymers, microporous absorption resin) [7,23,24]. Depending on the intended application of the obtained extracts, the biological assays (e.g., antibacterial, antifungal) can also be performed [7,25,26]. The activity-oriented separation (off-line: e.g., preparative scale bioguided fractionation, HPLC micro-fractionation; on-line: e.g., HPLC post-column (bio)chemical detection, biochromatography, electrophoretic enzyme assays) could also be considered. The final step to obtain phytocomplex or single molecules is the structure elucidation by means of off-line methods (e.g., UV-DAD, MS, NMR) or hyphenated techniques (e.g., HPLC-UV-DAD, HPLC-MS, GC-MS, HPLC-SPE-NMR, UPLC-DAD-TOF-MS) [7,27,28,29]. The technical and economic viability of any extraction and purification process should be evaluated in order to select production processes, marketing strategies, and remunerativeness [19].
The impressive contribution of plant-based extracts to virtually all aspects of human life has promoted their use to an increasing extent. For this reason, it is crucial to accelerate and reduce the cost of the production of new and innovative bioproducts and solutions. In view of the fact that the extraction process is a crucial first step in the development of new formulations, the research within this article has been designed to present the methods that could be used as a primary screening when no data are available on the chemical composition of examined extracts to evaluate the efficiency of the extraction techniques, to ensure that the active ingredients were not destroyed during preparation, and thus to reduce the time and costs of further purification of the obtained natural products. The choice of our examined plants was based on the ease and economic acquisition of raw materials (plants commonly found in the natural environment) and richness of active compounds that may be found in them. A total of 26 different extracts were tested for the content of phenolic compounds (phenols, tannins, anthocyanins, coumarins, flavones, flavonoids), vitamin C, quinones, quinines, resins, glycosides, sugars, antioxidant activity, and plant hormones. In most of the analyses, basic qualitative methods were used to provide a quick answer regarding the content of specific active compounds. The extracts were produced by means of ultrasound-assisted extraction, which is considered as a more environmentally friendly technique while allowing the extraction of bioactive compounds on a larger scale.
The aim of the publication was a comprehensive characterisation of plant extracts obtained from a number of higher plants. A given compound was determined using a series of methods, due to which it was possible to select visual protocols, the most sensitive ones indicating the presence of the given compound in the extract.

2. Results

The tested methods allowed rapid identification of the presence or absence of bioactives in the extract; however, in order to determine the exact amount of tested compounds, it is necessary to use more sophisticated analytical methods.
Throughout the paper, the following abbreviations were used for the particular extract: Alv L (solution/extract prepared based on aloe leaves), Am Fr (black chokeberry fruits), Arv H (common mugwort herb), Bv R (beetroot roots), Co F (common marigold flowers), Ea H (field horsetail herb), Ep F (purple coneflower flowers), Ep L (purple coneflower leaves), Hp H (St. John’s wort herb), Hr Fr (sea-buckthorn fruits), Lc S (red lentil seeds), Mc F (chamomile flowers), Ob H (basil herb), Pm H (broadleaf plantain herb), Poa H (common knotgrass herb), Ps S (pea seeds), Pta L (common bracken leaves), Sg L (giant goldenrod leaves), So R (comfrey roots), To F (common dandelion flowers), To L (common dandelion leaves), To R (common dandelion roots), Tp F (red clover flowers), Ur L (nettle leaves), Ur R (nettle roots), Vo R (valerian roots). In order to better visualise the obtained effects, the tables also show the tube with the extract before treatment (always the first on the left). The changes were usually observable immediately (up to 5 min) after following the appropriate procedures.

2.1. Phenolic Compounds (Total Phenolic Compounds, Tannins, Anthocyanins, Coumarins, Flavones, Flavonoids)

Several protocols for rapid phytochemical screening can be used to determine the presence of bioactive compounds in the examined samples. According to the literature, to assess the prevalence of phenolic compounds the ferric chloride test can be implemented. Authors who used this method found that these compounds were present after the appearance of a dark green [30,31,32], deep blue [31], violet [33], bluish black [34,35,36], or bluish-green [36] colour. Similar results were presented by other researchers who stated that violet [37], blue or green [38], or deep blue or black colour [39] indicates the presence of phenols. The second method, the lead acetate test, is also widely applied to detect these compounds in samples. Their presence can be confirmed when white precipitate is developed [31,40]. However, it is worth mentioning that the lead acetate test reveals very little helpful information and has the drawback of involving the heavy metal, lead, which creates environmental disposal problems. As a third method, the zinc hydrochloride test can be deployed—the appearance of yellow or orange colour after a few minutes proves the presence of phenols [37]. In another method, the Shinoda test, a yellow or orange colour demonstrates their existence [37]. The total phenolic content can be quantified using the Folin–Ciocalteu test, and when the bluish colour occurs it confirms the presence of phenolic compounds and their concentrations are verified by measuring the absorbance of the solutions [41].
The formation of green-blue [39], violet or blackish red [33,37] colouration in the ferric chloride test [39]; the yellow precipitate in the lead acetate test [31,37,39,42,43]; a red or magenta colour in the zinc hydrochloride test [37]; or a pink scarlet, green to blue, or crimson red colour emerging within minutes in the Shinoda test indicates flavonoids [31,33,36,37,43]. In the alkaline reagent test, the addition of sodium hydroxide solution causes an intense yellow colour which changes to colourless after the addition of hydrochloric acid, which may also suggest their presence [30,34,37]. In the aluminium chloride test, if the addition of aluminium chloride solution induces the light-yellow colour, the existence of flavonoid is observed. The addition of sodium hydroxide and hydrochloric acid makes the solution colourless, which also confirms their presence [32,39]. Among other methods used to identify these compounds, the ammonium test (a yellow colour at the ammonia layer [37,39]), the ammonia and sulphuric acid test (a yellow colour [30]), and the Millon’s test (a white precipitate which turns to red after gentle heating [37]) can be mentioned. Photos of the Millon’s test are presented in our previous article, where we conducted the analyses of proteins [44].
The ferric chloride test is likewise used for the analysis of tannins. Their presence can be confirmed when the formation of a greenish black precipitate [38,39,40,42,43,45] or a green, violet [37], or dark blue [33,38] colour is observed. Other authors have stated that the greater addition of ferric chloride changes the blue or greenish black colour to olive green [46]. The occurrence of a blackish blue colour indicates the presence of gallic tannins and a green-blackish colour shows the presence of catechol tannins [47]. The yellow [34,37,45,48] or white coloured precipitate in the lead acetate test [42,43] or a yellow to red precipitate in the alkaline reagent test may indicate the presence of tannins in the solution [37]. These compounds can also be detected in samples using other tests, among others: gelatin test (the white precipitate [37]), potassium dichromate test (the yellowish brown colour precipitate) [45], HCl test (the red coloured precipitate—phlobatannins [34,38,39,47]), and bromine water test (the buff coloured precipitate—condensed tannins; no precipitate—hydrolysable tannins [49]).
The sodium hydroxide test is employed in the analysis of anthocyanins (a blue-green colour [39]) and coumarins and flavones (a yellow colour [33,34,38,42]). In the sulphuric acid test, the yellowish orange colour indicates flavones [40] or anthocyanins, orange to crimson indicates flavonones, and yellow to orange colour indicates flavones [37].
The bromine water test can be used to detect the presence of glycosides (a yellow precipitate develops [37]) and carbohydrates (the solution discolours (by aldose)) [37]).
In the case of our results, the ferric chloride test clearly identified the presence of phenolic compounds in the following extracts: Am Fr, Ea H, Ep F, Ep L, Hr Fr, Pm H, Poa H, To F, To L, Tp F, Ur L. The colour of the extracts changed into a uniform dark green colour, without precipitation or turbidity of the solution (Table 1). Quantitative analysis of total polyphenol content, with the use of the Folin–Ciocalteu test, confirmed that qualitative methods show different sensitivities—indicating the presence of TPC in extracts that contain a great as well as a low amount of them but do not show their content even although these compounds are present. The highest levels of TPC could be found in Ep F, Pta L, and Ep L (3.2–2.2 mg·mL−1) and the lowest in Ps S, Ur R, Ur L, Lc S, and To R (0.07–0.18 mg·mL−1) (Table 1). The appearance of a white precipitate in the lead acetate test indicates the presence of phenols—Table 2. This was observed with the following extracts: Alv L, Bv R, Mc F, Ob H, Pm H, Ur R. White precipitation can also indicate the presence of tannins. Evident yellow/orange colour of the solution, which is typical for the presence of phenols in the zinc hydrochloride test, was observed in the extract Bv R, Co F, Ep F, Ep L, Sg L, Tp F, Ur L, Ur R, Vo R (Table 2). The results for the Shinoda test in most cases coincide with the results for the zinc hydrochloride test, used to detect phenols in plant extracts (Table 2).
The ferric chloride test was inconclusive in the determination of flavonoids in the extracts (Table 1). According to literature data, the appearance of a green-blue colour may indicate the presence of flavonoids [39]. No such change was observed for any of the tested extracts. The potential presence of flavonoids in the extract should be confirmed by another method. The Millon’s test (vide Table 4 in the work of Godlewska et al. [44]) revealed that the formation of precipitation, which could be considered as a positive result for the presence of flavonoids, occurred only in tubes with Co F (before boiling (1) an orange-brown precipitation formed, while after boiling (2) a white precipitation formed), EP F ((1) a brown precipitate, (2) a red precipitate), Lc S ((1) a white precipitate, (2) a white precipitate), Ps S ((1) a yellowish precipitate, (2) a white precipitate), So R ((1) a brown precipitate, (2) a brick-red precipitate). Yellow precipitation in the lead acetate test typical to tannins and flavonoids present in extracts was detected for Arv H, Co F, Ea H, Poa H, Pta L, To F, To L, To R, Vo R (Table 2). The colour change of the extract in the zinc hydrochloride test to red/magenta, indicating the presence of flavonoids, performed with the same test, was observed only for the extract Am Fr (Table 2). The presence of flavonoids detected by the Shinoda test was in the following extracts: Am Fr, Bv R, Ep F, Hr Fr, Lc S, Ps S, Tp F. The Shinoda test was more effective in detecting flavonoids in plant extracts than the zinc hydrochloride test (Table 2). The use of the alkaline reagent test did not allow the detection of flavonoids in plant extracts (Table 3). The ammonium test did not give a clear answer as to the content of flavonoids (Table 6). The unequivocal yellow colour, which indicates the presence of flavonoids in plant extracts, was observed only for Hr Fr, Poa H, and To R. A yellow colour, which indicates the presence of flavonoids in extracts using the ammonia and H2SO4 test, was observed for Co F, Ea H, Hr Fr, Mc F, To F, To R, and Tp F. After applying the ammonium chloride test, discoloration of the solution to some degree could be observed in most cases (with the exception of Am Fr).
In the case of tannin identification using the ferric chloride test, in addition to the greenish-black colour, which is typical for phenolic compounds, a precipitate was also observed, especially in the following extracts: Arv H, Bv R, Hp H, Mc F, Ob H, Pta L, Sg L, So R, Vo R (Table 1). In the case of the determination of tannins by the gelatin test, a change in the colour of the extract was mainly observed, and not the formation of a characteristic white precipitate (Table 3). This has been seen with the following extracts: Hp H, Lc S, and Ps S. A yellow to red precipitate indicating the presence of tannins in the plant extracts (alkaline reagent test) was present only in a few extracts: Ea H, Lc S, Pta L, To F, and Ur L (Table 3). Using the bromine water test, no tannins were detected in most botanical extracts (Table 3). The use of the potassium dichromate test did not allow the detection of tannins in plant extracts (Table 4). For this reason, the dichromate test for identifying tannins is not recommended, as it has given all negative results, and additionally dichromate poses a disposal issues. Furthermore, the bromine water test very rarely gave positive outcome for any class of compound and could easily be recommended not to be used. The characteristic yellowish-brown precipitate was not observed. A similar situation occurred in the case of detecting tannins (phlobatannins) with the HCl test. Dark (red) colour precipitate was observed only in the following extracts: So R and Vo R (Table 4).
Using the NaOH test, the presence of anthocyanins was not detected in the botanical extracts (Table 5). In none of the cases was the colour of the extract blue-green. The appearance of a yellow colour in the extract during this test indicates the presence of coumarins and flavones. Such a colour was unequivocally observed in the extracts Hr Fr, Mc F, Poa H, and To R. The H2SO4 test in many cases did not give a clear answer as to the presence of anthocyanins and flavones in plant extracts. A stable yellowish-orange colour that indicated the presence of flavones and anthocyanins was observed for Alv L, Am Fr, Hp H, Poa H, Pta L, Tp F, Ur L.

2.2. Vitamin C

In the DNPH test (2,4-dinitrophenylhydrazine), the formation of yellow precipitate indicates the presence of vitamin C [34]. The presence of vitamin C, using the DNPH test, was observed only for Lc S and Ps S extracts (Table 6).

2.3. Quinones, Quinines, Resin

The literature shows that the sulphuric acid test (the appearance of red colour) [38,42,43], the hydrochloric acid test (the formation of yellow precipitation) [34,37], and the ammonia test (a pink coloured precipitate) [38] can be applied to detect the presence of quinones/anthraquinones. In the sodium hydroxide test, a deep colouration (e.g., purple, red) can be attributed to the presence of quinine [33]. Furthermore, in the acetone test, a turbid solution implies the presence of resin [33].
The application of the H2SO4 test, HCl test, ammonia test, and NaOH test did not allow the detection of quinones and quinines in plant extracts (Table 7).
The acetone test was used to detect resins in plant extracts. Their presence (turbidity of the solution) was confirmed in the following extracts: Alv L, Am Fr, Arv H, Co F, Ea H, Lc S, Ob H, Pm H, Ps S, Pta L, Sg L, So R, To F, Ur R, and Vo R.

2.4. Glycosides

Glycosides can be found in samples using a number of rapid approaches. Authors who used the Keller–Killiani test showed that the presence of brown [36,38,42,43] or a reddish-brown ring at the junction of two layers [45] indicates the appearance of cardiac glycosides. Other authors stated that cardiac glycosides are present in sample when the colour of the acidic layer above the ring changes to bluish green [37,45] or greenish [36] and the lower layer to reddish brown [37] or violet [36]. In the Baljet test, the yellow to orange colour exhibits the occurrence of cardiac glycosides [37]. In the Borntrager’s tests (1), the anthraquinone glycosides can be found in samples when the ammoniacal (lower) layer shows a rose, pink, or red colour [37,39,42,43,50]. In the modified Borntrager’s tests (2), the pink colour indicates the presence of glycosides [32,38]. In the sulphuric acid test, the appearance of reddish precipitate indicates the presence of glycosides [40]. Photos are available in our previous article, in analyses of protein content (vide Table 4 in the work of Godlewska et al. [44]). The Molisch test can also be used as another method. In this protocol, the formation of a reddish-violet ring at the junction of two layers confirms the presence of glycosides [40]. The next method is Liebermann’s test, in which the appearance of a colour from violet through blue to green suggests the presence of glycosides [34]. Photos are presented in our previous article (vide Table 5 in the work of Godlewska et al. [44]).
No glycosides were detected in most botanical extracts using the bromine water test (Table 3). The use of the Baljet test did not show the presence of cardiac glycosides in most of the extracts tested (Table 8). Molisch’s test can be used to quickly screen extracts for the content of glycosides and sugars. The appearance of a reddish-violet ring at the junction of two liquids was easily visible in many botanical extracts (Table 9). The Borntrager test (2) was not effective in the detection of glycosides as well as sugars, and neither was the Borntrager test (1) in the detection of cyanogenic glycosides in the tested plant extracts. In all tubes subjected to the Liebermann’s test, no violet or blue colour was observed, which could likewise indicate the presence of these compounds. Extracts that may be considered to contain glycosides to some extent due to the greenish colour are Ep L and Mc F.
The Keller–Killiani test (Table 9), like the Baljet test (Table 8), did not provide full clarity on the presence of cardiac glycosides in plant extracts.

2.5. Sugars

Various protocols can be used to detect the presence of sugars. One of them is the Fehling’s test. The simple (reducing) sugars are present in samples when first a yellow, then a brick red precipitate is noted [31,33,37,39,42,43,45,47]. The next one is Benedict’s test—when the solution turns green [42,43] or red [31,40], or if the reddish-brown precipitate forms [33] it might suggest the presence of carbohydrates/reducing sugars. In the Molisch’s test, the appearance of a purple or reddish colour [38,47] or purple [30,34,37,40,45] or red brown [31,40,45] coloured ring at the junction of the two liquids shows the occurrence of carbohydrates. Additionally, the Borntrager’s test can also be applied, and when a change in colour of the ammonia layer is observed it indicates the presence of carbohydrates [37]. In the Selwinoff’s test, a red colouration implies fructose content in the solution [37], while in the Barfoed’s test, the formation of red precipitation reveals the presence of monosaccharaides [47].
The deployment of the bromine water test did not allow the determination of sugars in most botanical extracts (Table 3). No yellow/red precipitate was observed after using Fehling’s test, indicating the presence of sugars in the extracts (Table 10). Benedict’s test showed a clear change in the colour of the extract to green and the formation of a red-brown precipitate, which indicated the presence of sugars (reducing sugars) in almost all extracts tested. Selwinoff’s test gives a red coloured compound when linked with resorcinol. The colour of the extracts changed to red for Am Fr, Bv R, and Hp H. The red precipitate is the result of the Barfoed test, which indicates the presence of simple sugars and was observed in the following extracts: Arv H, Pta L, and To R.

2.6. Antioxidant Activity

Plant-derived extracts possessed varied antioxidant activity (Table 11). The analysis conducted using the DPPH assay showed that the highest radical scavenging potential demonstrated the following extracts: Pta L, Hp H, Ep F, Am Fr, Sg L, To L, and Ob H (9.57–2.48 µM Trolox·mL−1) and the lowest: Lc S, Ur L, Ur R, and Ps S (0.14–0.15 µM Trolox·mL−1). The greatest DPPH inhibition ratio showed extracts based on Pm H, Hr Fr, and Arv H (31.58–28.12%), while the smallest were based on Lc S, Ur L, Ps S, Ur R, and Ep L (2.00–2.37%). On the other hand, the relative ability of the antioxidants present in bioproducts to scavenge the ABTS free radicals was the strongest in Ep L, Ep F, Hp H, Am Fr, To L, Poa H, and Pta L (19.00–6.33 µM Trolox·mL−1), and the weakest in To R, Alv L, Ur L, Ea H, Hr Fr, and Lc S (0.81–1.90 µM Trolox·mL−1). The ABTS inhibition ratio was the highest for Poa H (5.37%) and So R (4.47%) and the lowest for Ob H, Sg L, and Pta L (0.34–0.54%). The most effective scavenging of the FRAP radical exhibited compounds present in extracts Pta L, Ep L, Ep F, Ob H, Sg L, Hp H, and Am Fr (20.25–8.73 µM Trolox·mL−1), while the least were in Lc S, Ps S, Ur R, To R, Ur L, and Alv L (0.40–1.38 µM Trolox·mL−1).

2.7. Plant Hormones

Of the seven plant hormones analysed (Table 12), gibberellic acid (GA3) was present in extracts in the highest amounts, especially in Sg L, Ur R, Pm H, To R, Ur L, and Ep F (359–319 μg∙mL−1). The following bioproducts, Arv H, Pta L, Hr Fr, Hp H, and Tp F (29.07–76.90 μg∙mL−1), contained the lowest amounts of GA3. The indole acetic acid (IAA) occurred in high levels in Ps S, Pm H, Ep F, To R, and Hr Fr (2.71–1.93 μg∙mL−1), while there were trace amounts in Arv H and Pta L. However, Arv H along with Hp H, Ob H, Ep F, Tp F, and Mc F (1.0–1.5 μg∙mL−1) contained the highest quantity of abscisic acid (ABA), whereas the amount of ABA in Am Fr, Ea H, Hr Fr, Lc S, Poa H, Ps S, Pta L, Ur L, and Ur R was at levels below detection. The concentration of benzoic acid (BA) was the highest in To R, To L, Ob H, and Pm H (0.48–0.28 μg∙mL−1), while it was present in trace amounts in Co F, Ea H, Hp H, Hr Fr, Poa H, Sg L, Ur L, and Ur R. Jasmonic acid (JA), salicylic acid (SA), and zeatin (Z) were present in trace amounts in most extracts. The quantity of SA was the highest in Lc S, Ea H, and Poa H (0.15–0.11 μg∙mL−1), while Z was highest in To F, So R, and To L (21.0–17.0 μg∙mL−1).

3. Discussion

Phenolic compounds (PCs) have well-documented beneficial effects on human health and exhibit antioxidant, anti-inflammatory, antimicrobial, antiviral, antitumoral, antidiabetic, anti-obesity, antiallergic, anti-lipidemic, antiproliferative, neuroprotective, and cardioprotective activities [51,52]. The main PCs include phenolic acids, flavonoids (flavonols, flavones, flavanones, flavanols, isoflavonoids, anthocyanins), tannins, stilbenes, and lignans [51,52,53,54]. These compounds are used in various industries, including food, nutraceutical, cosmetic, packaging, textile, pharmacy, and medicine [52,55,56,57].
Among the rapid, qualitative methods used to assess the presence of phenolic compounds can be mentioned ferric chloride test, lead acetate test, zinc hydrochloride test, Shinoda test, gelatin test, alkaline reagent test, bromine water test, potassium dichromate test, HCl test, NaOH test, H2SO4 test, aluminium chloride test, ammonium test, ammonia and H2SO4 test. By comparing these results with quantitative analysis data obtained with the use of the Folin–Ciocalteu test, it can be noted that qualitative tests vary significantly in sensitivity in detecting the targeted bioactive compounds. This assay is widely used to assess TPC in foods; however, it is not specific for their determinations and is highly dependent on the composition of the matrix, which can vary in terms of the types phenolics and the amount of particular compounds. For instance, reducing sugars or vitamin C may hamper the accuracy of this assay [58,59]. The Folin–Ciocalteu test showed that all extracts contained phenolic compounds in the range of 0.07 mg·mL−1 (Ps S) to 3.17 mg·mL−1 (Ep F). It can also be seen that the extracts prepared from Lc S and Ps S contained one of the lowest TPC contents despite the content of the vitamin C (the content of reducing sugars was not found). In contrast, the content of reducing sugars in extracts containing the highest amount of TPC, namely Ep L and Pta L, was confirmed in only one or two cases, respectively (the presence of vitamin C was not found). The point-biserial Correlation results for the comparison of methods used to detect phenolic compounds (PC) are included in Table S1. The analysis takes into account quantitative variable (Folin–Ciocalteu test results) and nominal variable (presence and absence of PC marked by plus or minus sign). There are two cases considered, depending on how to define the “−/+” sign: (a) treated as “+” (rpb+), (b) as “−“ (rpb−). The values of the point-biserial correlation coefficient rpb+ show that there is a positive, medium strength correlation for the Ferric chloride test, and a positive, low strength correlation for the Zinc hydrochloride test. When the rpb− coefficient is investigated, the findings indicate a similar pattern, with the difference that the Shinoda test is characterised by a positive, low strength correlation.
The ferric chloride test allowed detection of the presence of PC only in four extracts (Ep F, Ep L, To L, Am Fr) out of nine, with the highest concentration ranging from 3.17 mg·mL−1 to 1.0 mg·mL−1. Meanwhile, this test confirmed their presence in extracts that contained lower levels of them; for example, Ur L (0.13 mg·mL−1), Poa H (0.36 mg·mL−1), and Ea H (0.42 mg·mL−1). This assay was also appropriate for the determination of tannins in the following extracts: Arv H, Bv R, Hp H, Mc F, Ob H, Pta L, Sg L, So R, andVo R, but was ambiguous in the determination of flavonoids. The Acetate test allowed detection of phenols in Alv L, Bv R, Mc F, Ob H, Pm H, andUr R, as well as tannins and flavonoids in Arv H, Co F, Ea H, Poa H, Pta L, To F, To L, To R, and Vo R. The zinc hydrochloride test confirmed the presence of phenols in Bv R, Co F, Ep F, Ep L, Sg L, Tp F, Ur L, Ur R, and Vo R, and flavonoids in Am Fr. The results of the presence of phenols with the use of the Shinoda test in most cases coincide with the results for the zinc hydrochloride test, while the presence of flavonoids was verified in Am Fr, Bv R, Ep F, Hr Fr, Lc S, Ps S, and Tp F. However, the alkaline reagent test did not detect flavonoids in plant extracts. The Millon’s test can also be used to determine flavonoids, and in our extracts they were detected in Co F, EP F, Lc S, Ps S, and So R. The presence of tannins can be indicated using the gelatin test (positive for Hp H, Lc S, and Ps S), the alkaline reagent test (positive for Ea H, Lc S, Pta L, To F, and Ur L), and the HCl test (phlobatannins) (positive for So R and Vo R). However, the use of the bromine water test and the potassium dichromate test did not allow the detection of these compounds.
The NaOH test did not prove to be effective in the determination of anthocyanins, but it enabled the identification of coumarins and flavones (positive for Hr Fr, Mc F, Poa H, and To R). The H2SO4 test in many cases did not give a clear answer as to the presence of anthocyanins and flavones in plant extracts (positive for Alv L, Am Fr, Hp H, Poa H, Pta L, Tp F, and Ur L). Comparing both NaOH and H2SO4 tests for detecting anthocyanins and flavones, the latter seems to be more sensitive, but the presence of these active compounds in plant extracts was confirmed in most cases by both tests. The ammonium test did not give a clear answer as to the content of flavonoids (positive for Hr Fr, Poa H, and To R). The ammonia and H2SO4 test seems to be more precise in the detection of flavonoids in plant extracts than the ammonium test. The ammonia and H2SO4 test indicated the presence of flavonoids in Co F, Ea H, Hr Fr, Mc F, To F, To R, and Tp F. The ammonium chloride test showed that most extracts contained flavonoids (with the exception of Am Fr). The comparison of sensitivity of applied methods for the detection of polyphenolic compounds has been included in Supplementary Materials (Tables S1–S4). Among the examined tests for the presence of phenolic compounds in plant extracts, the most sensitive test was the ferric chloride test. The visual results largely coincide with the total polyphenol content, determined by the Folin–Ciocalteu test (Table S1). Failure to detect phenolic compounds with the ferric chloride test coincided with a very low concentration of these compounds in the extract using the spectrophotometric technique (Folin–Ciocalteu reagent). Phenolic compounds are common in plants and are easily extracted using water as a solvent. Based on the studies carried out, the ferric chloride test can also be recommended for the detection of tannins in plant extracts (Table S2). For the detection of flavonoids in plant extracts, many tests (aluminium chloride test, ammonium test, ammonia and H2SO4 test) gave inconclusive results. To the greatest extent, the results obtained for these tests coincided with the detection of flavonoids using the lead acetate test, which can be used as the first to screen plant extracts for the presence of flavonoids (Table S3). In the case of detecting anthocyanins in plant extracts, the NaOH test turned out to be useless—these compounds were not detected in any of the extracts tested. However, for their initial detection in extracts, the H2SO4 test can be used. The same applies to the screening of extracts for the presence of flavones. The H2SO4 test was more sensitive than the NaOH test (Table S4).
Vitamin C, an omnipresent plant and animal metabolite [60], exhibits multifarious biological and pharmaceutical functions [61]. It is crucial in the prevention of scurvy [60]; helps to lower blood cholesterol [62]; and is necessary for collagen, carnitine, and neurotransmitters biosynthesis [63,64]. It supports detoxification, assists the adequate function of the immune system, and is involved in the primary prevention of commonly encountered diseases, including diabetes, eye diseases, atherosclerosis [63] cardiovascular disease, and cancer [60]. In view of the fact that this vitamin is not synthesized by the human body, it has to be provided with diet [62]. Vitamin C is extensively utilised in the feed, food, and pharmaceutical industry as a nutritional supplement and preservative [61,65]. In our analysis, the DNPH test allowed detection of its presence only in Lc S and Ps S extracts. The study of this molecule is greatly handicapped by its oxidation under exposure to air, light, and heat.
Quinine, a cinchona alkaloid, belongs to the aryl amino alcohol group of drugs. It has played an invaluable role in the treatment of malaria since the 18th century and still plays a key role in the treatment of this disease. In turn, quinones, a class of compounds containing a benzene ring with a carbonyl group [66], are used in industry as oxidants, dehydrating agents [67], and dyes [68]. The analysis using the H2SO4 test, HCl test, ammonia test, and NaOH test did not confirm the presence of the tested compounds in any of the obtained extracts. The comparison of methods used to detect of quinones are presented in Supplementary Materials (Table S5). Among the tests for the detection of quinones in plant extracts (H2SO4 test, HCl test, ammonia test), the HCl test was the most sensitive.
Plant resins are a complex mixture of specialised metabolites; for example, alkaloids, phenols, and terpenes [69,70,71,72] as well as alcohols, aldehydes, esters, and amorphous neutral substances [69]. Due to their diverse biological activities (e.g., antimicrobial, anti-inflammatory, antioxidant, anticancer, antiulcer, haemostatic, immunostimulant) [70,72,73,74,75,76], resins are used as a raw material in the medical and pharmaceutical industry [70,73] but also as fuel additives, paint thinners, rosin, and varnishes as well as components in polishes [69]. One of the fast tests to verify the presence of resins is the Acetone test. This assay confirmed their existence in the following extracts: Alv L, Am Fr, Arv H, Co F, Ea H, Lc S, Ob H, Pm H, Ps S, Pta L, Sg L, So R, To F, Ur R, and Vo R.
Another group of compounds examined as a part of this study were glycosides, which can be sourced from plant or animal origin [77,78]. Various types of glycosides can be distinguished: among others, triterpene, β-sitosterol, flavonoid, iridoid, phenylpropanoid, anthraquinone, kaempferol, and saponin. The biological activity is strongly related to their stereochemistry [77,79]. Glycosides have been recognized and utilised as alternative drugs in the treatment of various cancers and have other notable therapeutic potential and clinical utility [77,79,80]. For instance, flavonoid glycosides possess antioxidant, anti-inflammatory, anti-allergic, anti-microbial, and anti-cancer activities and thus find use in the prevention and management of diseases [78,79]. Cardiac glycosides are used for the treatment of cardiac arrhythmia, congestive heart failure, and atrial fibrillation; exhibit strong anticancer activity; and evoke cell proliferation or activation of cell death by apoptosis or autophagy [77,78,81,82]. Visualisation of the presence of glycosides can be conducted with the use of various methods. The Molisch’s test proved to be the most sensitive in detecting these compounds (positive for Alv L, Arv H, Co F, Ea H, Lc S, Mc F, Ob H, Poa H, Ps S, Sg L, So R, Tp F, Ur L, and Ur R). However, the Borntrager test (1), the Borntrager test (2), the Keller–Killiani test, the Baljet test, and the bromine water test did not provide reliable confirmation of the presence of glycosides in plant extracts. The use of the Liebermann’s test also did not assure a full clarity of their appearance. The extracts which could be to some extent considered as a glycoside containing are Ep L and Mc F. The summary of protocols used for the confirmation of the presence of glycosides can be found in Supplementary Materials (Table S6). For the detection of glycosides in plant extracts, Molisch’s test is undoubtedly recommended.
The principal source of sugars, the main products of photosynthesis [83,84,85], are beet and cane sugar, while other sources may include honey, corn syrup, fruits, and vegetables [86]. The most abundant free sugars found in plants are disaccharides (sucrose and maltose) and monosaccharides (glucose and fructose) [83,87]. These compounds are used in food products to provide sweetness and energy, but also play a key role in preservation, fermentation, colour, flavour, and texture [86,88,89]. The highest sensitivity in determining the presence of sugars showed the Benedict’s test (all extracts with the exception of Lc S and Ps S) and Molisch’s test (positive for Alv L, Arv H, Co F, Ea H, Lc S, Mc F, Ob H, Poa H, Ps S, Sg L, So R, Tp F, Ur L, and Ur R). Selwinoff’s test (positive for Am Fr, Bv R, and Hp H) and the Barfoed test (positive for Arv H, Pta L, and To R) proved to be less effective in the identification of carbohydrates. The use of Fehling’s test, the Borntrager test (2), and the bromine water test were not sensitive in the detection of sugars. The comparison of methods used for the detection of sugars has been included in Supplementary Materials (Table S7). Both Molisch’s test and Benedict’s test were effective in detecting sugars in the tested plant extracts.
Antioxidants, compounds able to prevent/inhibit/reduce oxidation processes [90,91], can be sourced from microorganisms, plants, and animal tissues [92]. The industry has utilised them to prevent metal corrosion and oxidative degradation of polymers (e.g., rubbers, plastics, and adhesives), but they have also found use as food preservatives (enrichment and inhibition of disruption, sourness, and colour change) [90,91,92,93], and as stabilisers in fuels and lubricants [91,93], but also in pharmacology, cosmetics, and medicine [92] (in the prevention of degenerative illnesses, e.g., cancers, cardiovascular, and neurological diseases, cataracts and oxidative stress dysfunctions) [93]. In recent years, due to their numerous biological activities (e.g., anti-aging and anti-inflammatory), the interest in the utilisation of antioxidants is rapidly growing [92]. The measurements of antioxidant activity with the use of three examined assays (DPPH, ABTS, and FRAP assays) revealed that Pta L, Hp H, Ep F, and Am Fr had the highest reducing power. Additionally, the greatest antioxidant activity was also noted for Sg L, Ob H (DPPH assay and FRAP assay), To L (DPPH assay and ABTS assay), and Ep L (ABTS assay and FRAP assay). The extract Poa H was characterised by one of the highest activities in the ABTS test, while in the DPPH test and FRAP test it was characterised by one of the lowest. The lowest reducing power was observed for Vo R, Ea H, Poa H, To R, Alv L, Ur R, Ps S, Ur L, and Lc S (all three assays) as well as for Ur R and Ps S (DPPH assay and FRAP assay). Therefore, it can be seen that despite the differences between these tests, the results obtained are relatively comparable.
Plant hormones, which can be found in plants, algae, and plant-associated bacteria and fungi, play a vital role in plant growth and development (e.g., promote fruit ripening and leaf drop, stimulate seed germination and gemmation, increase yield and resistance to adverse environmental conditions) [94,95,96,97]. The use of these compounds in agriculture and horticulture is of great importance, and since their first discovery and commercial availability, farmers have incorporated them into the crop production to improve numerous aspects of the cultivation processes [96,98,99]. The conducted studies proved that the obtained extracts could constitute a source of plant hormones, especially gibberellic acid (e.g., Ep F, Pm H, Sg L, To R, Ur L, Ur R).

4. Materials and Methods

4.1. Chemicals and Reagents

The following chemicals were used in this study: sodium carbonate (Sigma Aldrich, St. Louis, MI, USA), sodium hydroxide (Avantor, Radnor Township, PA, USA), sulphuric acid (Avantor), ammonium hydroxide (Supelco, Bellefonte, PA, USA), acetone (Stanlab, Lagos, Nigeria), chloroform (Avantor), acetic acid (Supelco), glacial acetic acid (Supelco), hydrochloric acid (Avantor), iron chloride (Sigma Aldrich), lead acetate (Sigma Aldrich), zinc dust (Roth), magnesium turnings (Sigma Aldrich), Folin–Ciocalteu’s phenol reagent (Sigma Aldrich), sodium carbonate (Sigma Aldrich), gelatin (Sigma Aldrich), sodium chloride (Sigma Aldrich), bromine water (Carlo Erba, Milan, Italy), potassium dichromate (Sigma Aldrich), aluminium chloride (Sigma Aldrich), 2,4-dinitrophenylhydrazine (PanReac AppliChem, Darmstadt, Germany), sodium picrate (Merck, Rahway, NJ, USA), Trolox (Sigma Aldrich), gallic acid (Sigma Aldrich), diphenyl−2-picrylhydrazyl (DPPH) (Sigma Aldrich), azino-bis−3-ethylbenzthiazoline6-sulphonic acid (ABTS) (Sigma Aldrich), tripyridyl-S-triazine (TPTZ) (Sigma Aldrich), ethanol (TH.GEYER, Höxter, Germany), methanol (TH.GEYER), mercuric nitrate (Sigma Aldrich), mercurous nitrate (Alfa Aesar, Haverhill, MA, USA), nitric acid (Merck), ammonia solution 25% (Supelco), α-naphthol (Carlo Erba), copper (II) sulphate (Sigma Aldrich), potassium tartrate (Sigma Aldrich), trisodium citrate dihydrate (Alfa Aesar), resorcinol (Sigma Aldrich), copper acetate (Roth), phytohormone standards Z, BA, JA, SA, ABA (Sigma-Aldrich), GA3, IAA (OlChemIm Ltd., Olomouc, Czech Republic), methanol (HPLC quality, Merck), acetonitrile (HPLC quality, Merck), and acetic acid (HPLC quality, Merck).

4.2. Plant Materials Used for the Production of Extracts

The main factors in the selection of raw materials were their prevalence in Europe, ease, and low cost of acquisition, as well as the content of biologically active compounds [44]. The biomasses were purchased (FLOS, Herbisarium) or collected from the natural environment (Wrocław, Poland). The harvesting time was adjusted to the level of biologically active components in the plants (based on literature data). The list of plants (with abbreviations) being used, included aloe leaves, black chokeberry fruits, common mugwort herb, beetroot roots, common marigold flowers, field horsetail herb, purple coneflower flowers, purple coneflower leaves, St. John’s wort herb, sea-buckthorn fruits, red lentil seeds, chamomile flowers, basil herb, broadleaf plantain herb, common knotgrass herb, pea seeds, common bracken leaves, giant goldenrod leaves, comfrey roots, common dandelion flowers, common dandelion leaves, common dandelion roots, red clover flowers, nettle leaves, nettle roots, and valerian roots.

4.3. Extraction

Plant-based extracts were produced through ultrasound-assisted extraction (UAE) with the use of a UP 50 H homogeniser (Hielscher Ultrasonics GmbH, Brandenburg, Germany). Raw materials (dried, 500 μm mesh size) were macerated with deionised water (ratio 1:20 w/v) at room temperature. After 30 min, the mixtures were sonicated (30 min) and centrifuged (4500 rpm, 10 min, Heraeus Megafuge 40, rotor TX-750, Thermo Scientific, Waltham, MA, USA). The analyses of bioactive compounds and antioxidant activity were performed in the obtained supernatants [44].

4.4. Analyses of Extracts

4.4.1. Phenolic Compounds

Total Phenolic Compounds

Ferric chloride test—to each extract (3 mL), neutral ferric chloride solution (5%, 5 drops) was added [30].
Lead acetate test—to each extract (2.5 mL), a lead acetate solution (10%, 1.5 mL) was added [40].
Zinc hydrochloride test—to each extract (3 mL), a pinch of zinc dust and concentrated HCl were added (5 drops) [37].
Shinoda test—to each extract (3 mL), few turnings of magnesium and concentrated HCl (5 drops) were added [37].
Folin–Ciocalteu test—to the extracts (0.1 mL), Folin–Ciocalteu’s phenol reagent (0.2 mL) and distilled water (2.0 mL) were added, and the solution was incubated (room temperature, 3 min). Then, Na2CO3 (20 mg·mL−1, 1.0 mL) was added, and the mixtures were incubated in the dark (1 h). The absorbance was determined at 765 nm using a spectrophotometer (Varian Cary 50 Conc. Instrument, Victoria, Australia). The results were expressed as gallic acid equivalents (GAE) [100].

Tannins

Gelatin test—to the extracts (3 mL), 1% gelatin solution containing 10% sodium chloride (15 drops) was added [37].
Alkaline reagent test—to the extracts (3 mL), NaOH (20%, 10 drops) was added [37].
Bromine water test—to the extract solution (2 mL), bromine water (0.2 mL) was added [49].
Ferric chloride test—to each extract (3 mL), neutral ferric chloride solution (5%, 5 drops) was added [39].
Lead acetate test—to each extract (2.5 mL), lead acetate solution (10%, 1.5 mL) was added [45].
Potassium dichromate test—to each extract (5 mL), potassium dichromate solution (10%, 1 mL) was added [45].
HCl test (phlobatannins)—to each extract (2 mL), HCl (1%, 2 mL) was added [38], then the mixture was boiled (5 min) [34,39].

Anthocyanins

NaOH test—each extract was treated with NaOH (10%, 2 mL) [39].
H2SO4 test—extracts (3 mL) were treated with H2SO4 (15 drops) [37].

Coumarins

NaOH test—each extract was treated with NaOH (10%, 2 mL) [34,42].

Flavones

NaOH test—each extract was treated with NaOH (10%, 2 mL) [40].
H2SO4 test—extracts (3 mL) were treated with H2SO4 (15 drops) [37].

Flavonoids

Alkaline reagent test—to the extracts (3 mL), NaOH (20%, 10 drops) and HCl (20%, 10 drops) were added [37].
Aluminium chloride test—extracts (2 mL) were shaken with AlCl3 solution (1%, 0.5 mL). Next, NaOH (20%, 0.5 mL) and HCl (20%, 0.5 mL) were added [39].
Ammonium test—extracts (1 mL) were treated with NH3(aq) (10%, 2 mL) and H2SO4 (5 drops) [39].
Ammonia and H2SO4 test—to each extract (1 mL), ammonia solution (10%, 2 mL) and concentrated H2SO4 (5 drops) were added [30].
Ferric chloride test—to each extract (3 mL), neutral ferric chloride solution (5%, 5 drops) was added [39].
Lead acetate test—to each extract (2.5 mL), lead acetate solution (10%, 1.5 mL) was added [37].
Millon’s test—extracts (2 mL) were mixed with Millon’s reagent (2 mL) and boiled (5 min) (Ramya et al., 2019). Methodology similar to the methodology of proteins described in our previous article [44].
Shinoda test—to each extract (3 mL), a few turnings of magnesium and concentrated HCl (5 drops) were added [37].
Zinc hydrochloride test—to each extract (3 mL), a pinch of zinc dust and concentrated HCl were added (5 drops) [37].

4.4.2. Vitamin C

DNPH test—2 mL of the test solution was treated with 2,4-dinitrophenyl hydrazine dissolved in conc. H2SO4 [34].

4.4.3. Quinones

H2SO4 test—extracts (2 mL) were shaken (5 min) with conc. H2SO4 (2 mL) [43].
HCl test—extracts (2 mL) were treated with HCl (5 mL) [34].
Ammonia test (anthraquinones)—to each extract (2 mL), NH3(aq) (10%, 15 drops) was added [38].

4.4.4. Quinines

NaOH test—extracts (1 mL) were mixed with NaOH (5%, 1 mL) [33].

4.4.5. Resin

Acetone test—extracts (1 mL) were treated with acetone (1 mL) [33].

4.4.6. Glycosides

Borntrager test (cardiac glycosides)—extracts (5 mL) were treated with conc. H2SO4 (1 mL), glacial acetic acid (2 mL) and FeCl3 solutions (5%, 3 drops) [42].
Baljet test (cardiac glycosides)—extract (2 mL) were mixed with a solution of sodium picrate (5 drops) [37].
Bromine water test (cardiac glycosides)—to the extract solution (2 mL), bromine water (0.2 mL) was added [37].
Borntrager’s tests (1) (cyanogenic glycosides)—diluted H2SO4 (2 mL) was added to each extract (2 mL). Solution was boiled (10 min) and filtered. The filtrate (1 mL) was shaken with chloroform (1 mL), then the separated chloroform layer (lower part) was shaken with NH3 solution (10%, 0.5%) [39].
Borntrager’s tests (2)—extracts (2 mL) were mixed with chloroform (2 mL) and NH3 solution (2 mL) [32,38].
H2SO4 test (glycosides)—extracts (3 mL) were treated with H2SO4 (1 mL) (Shetty and V 2012). Methodology similar to the methodology of proteins described in our previous article [44].
Molisch’s test—to each extract (2 mL), Molisch’s reagent (2 drops, ethanolic solution of α-naphthol (5%)) was added and mixed well. Next, conc. H2SO4 (1 mL) was added and allowed to stand for a few minutes [40].
Liebermann’s test—methodology similar to previously described analyses of steroids (vide: Liebermann–Burchard test for steroids, [44]). Extracts (1 mL) were mixed with chloroform (1 mL) and acetic acid (2 mL). Then, conc. H2SO4 (2 drops) was added [34].

4.4.7. Sugars

Fehling’s test—Fehling’s A solution (aqueous solution of copper (II) sulphate) (1 mL) and Fehling’s B solution (solution of potassium tartrate) (1 mL) were mixed and boiled (1 min). Next, extracts (2 mL) were added to the above mixture and boiling continued (water bath, 5 min) [42].
Benedict’s test—Benedict’s reagent (2 mL) and extracts (2 mL) were mixed and heated (boiling water bath, 5 min) [42]. Benedict’s solution consisted of 17.0 g of trisodium citrate dihydrate, 10.0 g of anhydrous sodium carbonate, 1.74 g of copper (II) sulphate, and 100 mL of water.
Molisch’s test—to each extract (2 mL), Molisch’s reagent (2 drops, ethanolic solution of α-naphthol (5%)) was added and mixed well. Next, conc. H2SO4 (1 mL) was added and allowed to stand for few minutes [34].
Bromine water test—to the extract solution (2 mL) 0.2 mL of bromine water [37] was added.
Borntrager’s test—extracts (2 mL) were mixed with chloroform (2 mL) and NH3 solution (2 mL) [37].
Selwinoff’s test—to the extracts (3 mL), Selwinoff’s reagent (1 mL) was added and boiled (10 min) [37]. Selwinoff’s solution was prepared by dissolving 110 mg of resorcinol in 220 mL of 3N HCl.
Barfoed’s test—extracts (2 mL) were mixed with Barfoed’s reagent (1 mL) and heated (water bath, 2 min) [47]. Barfoed’s solution was prepared by dissolving 13.3 g of copper acetate in 200 mL of water and then 1.8 mL of glacial acetic acid was added.

4.4.8. Antioxidant Activity

DPPH assay—extracts (0.5 mL, diluted 100 or 1000 times) were mixed with ethanol (1.5 mL) and DPPH solution (0.5 mL), vigorously shaken, and left in the dark (10 min). The absorbance was measured at 517 nm [100].
ABTS assay—extracts (30 µL) were mixed with ABTS solution (3 mL) and left in the dark (6 min). The absorbance was measured at 734 nm [100].
FRAP assay—extracts (1 mL) were mixed with FRAP solution (3 mL) and after 10 min the absorbance at 593 nm was measured [100].
The percentage of DPPH and ABTS scavenging effects were calculated by the following equation:
I n h i b i t i o n   r a t i o   ( % ) = A c o n t r o l − A s a m p l e A c o n t r o l × 100 %
where Acontrol is the absorbance of the addition of ethanol and Asample is the absorbance of tested extracts.

4.4.9. Plant Hormones

HPLC—qualitative and quantitative HPLC chromatographic analysis of plant hormones were performed in the reverse phase system, using a LaChrom-Merck liquid chromatograph with a DAD diode detector (L-7450), a pump (L-7100), a degasser (L-7612), a 20 µL dosing loop with a thermostat (L-7360), a Rheodyne dispenser, and a steel column LiChrocart C18 250 mm × 4.6 mm filled with a stationary phase with a grain diameter of dp = 5 µm. The samples were analysed at 30 °C. Separation of standard substances was performed using an isocratic elution in 1% aqueous solution of acetic acid and acetonitrile (75:25, v/v) at pH 4.0. Mobile phases for the determination of hormones in the plant samples consisted of 40% acetonitrile—0.1% acetic acid in water (eluent A) and 0.1% acetic acid in methanol (eluent B). The following gradient was used: 0–18 min, 100% A; 18–25 min, linear gradient up to 100% B; 25–35 min 100% B; 35–40 min, linear gradient to 100% A. Post-run time was 15 min. Elution was performed with a solvent flow rate of 0.8 mL·min−1 and an injection size of 20 µL. Detection was carried out at a wavelength of λ = 230 to 287 nm. Hormones were identified by comparing their retention times (tR) with the standards. Abscisic acid (ABA), benzoic acid (BA), gibberellic acid (GA3), indole acetic acid (IAA), jasmonic acid (JA), salicylic acid (SA), zeatin (Z), zeatin riboside (RZ), and isipentenyl adenine (IP) in the tested extracts was calculated on the basis of a calibration curve determined for each identified hormone. All samples were filtered through 0.22 µm membrane filters before injection into HPLC [101,102].

5. Conclusions

The current study represents the systematic screening of bioactive compounds extracted from twenty-six biomasses. The detailed phytochemical study of the content of phenolic compounds (phenols, tannins, anthocyanins, coumarins, flavones, flavonoids), vitamin C, quinones, quinines, resins, glycosides, and sugars, as well as antioxidant activity and the content of plant hormones, have been reported. The applied protocols are accessible, inexpensive, and provide a quick answer regarding the presence or absence of bioactive compounds. Several methods could be used for rapid screening, while modern analytical methods are necessary for the final confirmation of the concentration of bioactive compounds.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/molecules28145572/s1, Table S1: The comparison of methods used to detect phenolic compounds (PC); Table S2: The comparison of methods used to detect tannins (TN); Table S3: The comparison of methods used to detect flavonoids (FD); Table S4: The comparison of methods used to detect anthocyanins (AC), and flavones (FL); Table S5: The comparison of methods used to detect quinones (QNO); Table S6: The comparison of methods used to detect glycosides; Table S7: The comparison of methods used to detect sugars.

Author Contributions

Conceptualisation, K.G.; methodology, K.G. and A.N.; formal analysis, K.G., P.P. and I.M.; investigation, K.G. and A.N.; resources, K.G.; writing—original draft preparation, K.G., P.P. and I.M.; supervision, K.G. and I.M.; funding acquisition, K.G. All authors have read and agreed to the published version of the manuscript.

Funding

This work was financed in the framework of the grant entitled Mechanism of Action of Novel Plant-Derived Extracts and Their Impact on Stress Resilience of Arabidopsis thaliana (2018/29/N/NZ9/02430) attributed by The National Science Centre in Poland. The APC is co-financed by Wrocław University of Environmental and Life Sciences.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

Sample Availability

Not applicable.

References

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Table
Table 1. The results of ferric chloride test and Folin–Ciocalteu test (PC—phenolic compounds, TN—tannins, FD—flavonoids).
Table 1. The results of ferric chloride test and Folin–Ciocalteu test (PC—phenolic compounds, TN—tannins, FD—flavonoids).
MethodFerric Chloride TestFolin–Ciocalteu Test
ExtractObservationPCTNFDPhotomg·mL−1
Alv LA change in the colour of the solution to brown
with a green glow was observed		−−−Molecules 28 05572 i0010.36 ± 0.00
Am FrThe appearance of a dark green colour was observed++−Molecules 28 05572 i0021.13 ± 0.02
Arv HThe appearance of a dark green colour and
the precipitation of a fine precipitate were observed		++−Molecules 28 05572 i0031.00 ± 0.12
Bv RThe appearance of a brown colour and
the formation of a precipitate were observed		−−−Molecules 28 05572 i0040.53 ± 0.02
Co FA change in colour of the solution to dark green and
a jelly-like consistency was observed		++−Molecules 28 05572 i0050.75 ± 0.00
Ea HThe appearance of a dark green colour was observed++−Molecules 28 05572 i0060.42 ± 0.02
Ep FThe appearance of a dark green colour was observed++−Molecules 28 05572 i0073.17 ± 0.03
Ep LThe appearance of a dark green colour was observed++−Molecules 28 05572 i0082.20 ± 0.02
Hp HA dark green colour change and
precipitation were observed		++−Molecules 28 05572 i0091.47 ± 0.05
Hr FrThe appearance of a dark green colour was observed++−Molecules 28 05572 i0100.52 ± 0.02
Lc SA colour change to dirty yellow was observed−−−Molecules 28 05572 i0110.13 ± 0.01
Mc FThe appearance of a dark green colour and
turbidity of the solution were observed		++−Molecules 28 05572 i0120.50 ± 0.02
Ob HA colour change to dark green was observed and
a fine precipitate formed		++−Molecules 28 05572 i0131.44 ± 0.03
Pm HA colour change to dark green was observed++−Molecules 28 05572 i0140.92 ± 0.04
Poa HThe appearance of a dark green colour was observed++−Molecules 28 05572 i0150.36 ± 0.00
Ps SA slight orange colour was observed−−−Molecules 28 05572 i0160.07 ± 0.02
Pta LA dark green colour change and
turbidity of the solution were observed		++−Molecules 28 05572 i0173.11 ± 0.03
Sg LThe appearance of a dark green colour and
turbidity of the solution were observed		++−Molecules 28 05572 i0181.65 ± 0.04
So RThe appearance of a dark green colour and
the formation of a precipitate were observed		++−Molecules 28 05572 i0190.88 ± 0.02
To FThe appearance of a dark green colour was observed++−Molecules 28 05572 i0200.55 ± 0.00
To LThe appearance of a dark green colour was observed++−Molecules 28 05572 i0211.14 ± 0.02
To RThe appearance of an olive colour was observed−+−Molecules 28 05572 i0220.18 ± 0.01
Tp FThe appearance of a dark green colour was observed++−Molecules 28 05572 i0230.82 ± 0.04
Ur LThe appearance of a dark green colour was observed++−Molecules 28 05572 i0240.13 ± 0.01
Ur RThe appearance of a dirty yellow colour was observed−−−Molecules 28 05572 i0250.09 ± 0.01
Vo RThe appearance of a dark green colour and
the formation of a precipitate were observed		++−Molecules 28 05572 i0260.46 ± 0.01
+—present; −—not present. Abbreviations: Alv L—aloe leaves; Am Fr—black chokeberry fruits; Arv H—common mugwort herb; Bv R—beetroot roots; Co F—common marigold flowers; Ea H—field horsetail herb; Ep F—purple coneflower flowers; Ep L—purple coneflower leaves; Hp H—St. John’s wort herb; Hr Fr—sea-buckthorn fruits; Lc S—red lentil seeds; Mc F—chamomile flowers; Ob H—basil herb; Pm H—broadleaf plantain herb; Poa H—common knotgrass herb; Ps S—pea seeds; Pta L—common bracken leaves; Sg L—giant goldenrod leaves; So R—comfrey roots; To F—common dandelion flowers; To L—common dandelion leaves; To R—common dandelion roots; Tp F—red clover flowers; Ur L—nettle leaves; Ur R—nettle roots; Vo R—valerian roots.
Table
Table 2. The results of lead acetate test, zinc hydrochloride test, and Shinoda test (PC—phenolic compounds, TN—tannins, FD—flavonoids).
Table 2. The results of lead acetate test, zinc hydrochloride test, and Shinoda test (PC—phenolic compounds, TN—tannins, FD—flavonoids).
MethodLead Acetate TestZinc Hydrochloride TestShinoda Test
ExtractObservationPCTNFDPhotoObservationPCFDPhotoObservationPCFDPhoto
Alv LPrecipitation of a white precipitate and a change in colour of the solution to beige-milky were observed++−Molecules 28 05572 i027Change of colour of the solution to light green, foaming−−Molecules 28 05572 i028The colour of the
solution changes to
orange, the formation of foam in the upper part of the solution		+−Molecules 28 05572 i029
Am FrA colour change to bottle green was observed−−−Molecules 28 05572 i030The colour of the
solution changes to pink		−+Molecules 28 05572 i031The colour of the
solution changes to bright red		−+Molecules 28 05572 i032
Arv HPrecipitation and a colour change to olive green were observed−/+++Molecules 28 05572 i033Change of the colour of the solution to light yellow-green,
formation of
precipitate and foam		−/+−Molecules 28 05572 i034Change of colour of the solution to light orange, foam formation+−Molecules 28 05572 i035
Bv RA change in colour of the
solution to strawberry colour and precipitation were
observed		++−Molecules 28 05572 i036The colour of the
solution changes to yellow, the release of foam		+−Molecules 28 05572 i037The colour of the
solution changes to dark red		−+Molecules 28 05572 i038
Co FPrecipitation of a jelly-like precipitate and colour change to dirty yellow were observed−/+++Molecules 28 05572 i039The colour of the
solution changes to yellow, the formation of a grey precipitate in the upper part of the tube		+−Molecules 28 05572 i040The formation of a
orange jelly-like
consistency		−/+−Molecules 28 05572 i041
Ea HA colour change to dirty
yellow and precipitation were observed		−/+++Molecules 28 05572 i042Change of the colour of the solution to lemon, release of foam−/+−Molecules 28 05572 i043The colour of the
solution changes to bright orange		+−Molecules 28 05572 i044
Ep FTurbidity of the solution and an olive colour were
observed		−−−Molecules 28 05572 i045The colour of the
solution changes to
orange		+−Molecules 28 05572 i046The colour of the
solution changes to red		−+Molecules 28 05572 i047
Ep LA light green colour was
observed and a slight
turbidity appeared		−−−Molecules 28 05572 i048The colour of the
solution changes to yellow-orange		+−Molecules 28 05572 i049The colour of the
solution changes to
orange		+−Molecules 28 05572 i050
Hp HA colour change to olive green and turbidity of the solution were observed−−−Molecules 28 05572 i051Discolouration of the
solution, formation of foam and precipitate		−−Molecules 28 05572 i052Change of colour of the solution to light orange, foam formation−/+−Molecules 28 05572 i053
Hr FrThe solution turned yellow−−−Molecules 28 05572 i054Change of the colour of the solution to cloudy grey, release of foam−−Molecules 28 05572 i055The colour of the
solution changes to pink-red		−+Molecules 28 05572 i056
Lc SA colour change of one
degree (darker) was
observed		−−−Molecules 28 05572 i057The colour of the
solution changes to pale yellow, the
formation of foam		−/+−Molecules 28 05572 i058The colour of the
solution changes to light pink		−+Molecules 28 05572 i059
Mc FPrecipitation of a white precipitate was observed++−Molecules 28 05572 i060Change of the colour of the solution to light lemon, precipitation of a delicate precipitate−/+−Molecules 28 05572 i061no colour change,
evolution of foam in the upper part
of the solution		−/+−Molecules 28 05572 i062
Ob HPrecipitation of a white
precipitate and a colour change to olive green
were observed		++−Molecules 28 05572 i063The colour of the
solution changes to yellow-green,
the release of foam		−/+−Molecules 28 05572 i064The colour of the
solution changes to bright orange		+−Molecules 28 05572 i065
Pm HPrecipitation of a white precipitate and a colour change to olive green
were observed		++−Molecules 28 05572 i066Change of colour of the solution to yellow-green, foaming−/+−Molecules 28 05572 i067The colour of the
solution changes to
orange		+−Molecules 28 05572 i068
Poa HA colour change to intense yellow and precipitation were observed−++Molecules 28 05572 i069Precipitation of zinc (grey), discolouration of the solution−−Molecules 28 05572 i070The colour of the
solution changes to bright orange		+−Molecules 28 05572 i071
Ps SNo changes were observed−−−Molecules 28 05572 i072Exudation of a large amount of foam and its deposition on the walls of the test tube−−Molecules 28 05572 i073The colour of the
solution changes to light pink		−+Molecules 28 05572 i074
Pta LPrecipitation was observed−++Molecules 28 05572 i075The colour of the
solution changes to light yellow		−/+−Molecules 28 05572 i076The colour of the
solution changes to
yellow, the release of foam		+−Molecules 28 05572 i077
Sg LA colour change to olive green was observed−−−Molecules 28 05572 i078The colour of the
solution changes to yellow, the release of foam		+−Molecules 28 05572 i079The colour of the
solution changes to
amber-orange		+−Molecules 28 05572 i080
So RThe appearance of a
gelatinous form and a change in the colour of the solution to brown were
observed		−−−Molecules 28 05572 i081Formation of a
gelatinous consistency		−−Molecules 28 05572 i082Formation of a
gelatinous consistency		−−Molecules 28 05572 i083
To FA colour change to dirty
yellow and precipitation were observed		−++Molecules 28 05572 i084The colour of the
solution changes to pale yellow,
the formation of foam		−/+−Molecules 28 05572 i085The colour of the
solution changes to bright orange		+−Molecules 28 05572 i086
To LA colour change to olive and precipitation were
observed		−/+++Molecules 28 05572 i087The colour of the
solution changes to pale yellow,
the formation of foam		−/+−Molecules 28 05572 i088The colour of the
solution changes to bright orange		+−Molecules 28 05572 i089
To RA change in the colour of the solution to yellow and the formation of a fine
precipitate were observed		−/+++Molecules 28 05572 i090Turbidity of the
solution		−−Molecules 28 05572 i091The colour of the
solution changes to light yellow		−/+−Molecules 28 05572 i092
Tp FA colour change of the
solution to olive green was
observed		−−−Molecules 28 05572 i093Change of colour of the solution to light
orange, precipitation of a fine precipitate		+−Molecules 28 05572 i094The colour of the
solution changes to
orange-red		−+Molecules 28 05572 i095
Ur LA change in colour to lemon was observed−−−Molecules 28 05572 i096Change of colour of the solution to yellow-
orange, foaming		+−Molecules 28 05572 i097The colour of the
solution changes to
brown-orange		−/+−Molecules 28 05572 i098
Ur RThe appearance of a white precipitate was observed++−Molecules 28 05572 i099Change of the colour of the solution to lemon, release of foam+−Molecules 28 05572 i100The colour of the
solution changes to light yellow		−/+−Molecules 28 05572 i101
Vo RPrecipitation was observed+++Molecules 28 05572 i102Change of colour of the solution to yellow,
separation of a grey
precipitate		+−Molecules 28 05572 i103The colour of the
solution changes to
amber-orange		+−Molecules 28 05572 i104
+—present; −—not present; −/+—not obvious. Abbreviations: Alv L—aloe leaves; Am Fr—black chokeberry fruits; Arv H—common mugwort herb; Bv R—beetroot roots; Co F—common marigold flowers; Ea H—field horsetail herb; Ep F—purple coneflower flowers; Ep L—purple coneflower leaves; Hp H—St. John’s wort herb; Hr Fr—sea-buckthorn fruits; Lc S—red lentil seeds; Mc F—chamomile flowers; Ob H—basil herb; Pm H—broadleaf plantain herb; Poa H—common knotgrass herb; Ps S—pea seeds; Pta L—common bracken leaves; Sg L—giant goldenrod leaves; So R—comfrey roots; To F—common dandelion flowers; To L—common dandelion leaves; To R—common dandelion roots; Tp F—red clover flowers; Ur L—nettle leaves; Ur R—nettle roots; Vo R—valerian roots.
Table
Table 3. The results of gelatin test, alkaline reagent test, and bromine water test (TN—tannins, FD—flavonoids, GS—glycosides, SG—sugars).
Table 3. The results of gelatin test, alkaline reagent test, and bromine water test (TN—tannins, FD—flavonoids, GS—glycosides, SG—sugars).
MethodGelatin TestAlkaline Reagent TestBromine Water Test
ExtractObservationTNPhotoObservationTNFDPhotoObservationTNGSSGPhoto
Alv LThe formation of two phases: dark and light orange−Molecules 28 05572 i105Brown-orange colour of the solution and a yellow glow. After addition of HCl:
Orange colour of the solution and
formation of a dark orange glow		−−Molecules 28 05572 i106The colour of the
solution changes
to amber-orange		−−−Molecules 28 05572 i107
Am FrThe formation of two phases: dark brown and pink with a delicate
precipitate		−Molecules 28 05572 i108No yellow glow/green colour of the
solution. After addition of HCl: The
formation of 3 phases: brown, red
and black		−−Molecules 28 05572 i109The colour of the
solution changes
to orange		−−−Molecules 28 05572 i110
Arv HThe colour of the
solution changes to olive green		−Molecules 28 05572 i111Brown-orange colour of the solution and
a yellow glow. After addition of HCl:
Orange colour of the solution		−−Molecules 28 05572 i112Change of colour of the solution to
orange,
precipitation 		+−/+−Molecules 28 05572 i113
Bv RThe formation of two phases:
raspberry and
dark-burgundy		−Molecules 28 05572 i114Orange colour of the solution.
After addition of HCl: Red-orange colour of the solution		−−Molecules 28 05572 i115The colour of the
solution changes
to orange		−−−Molecules 28 05572 i116
Co FThe colour of the
solution changes to an intense orange		−Molecules 28 05572 i117Orange colour of the solution and
a yellow glow. After addition of HCl:
Orange-amber colour of the solution and formation of a yellow glow		−−Molecules 28 05572 i118No changes were observed−−−Molecules 28 05572 i119
Ea HThe colour of the
solution changes to an intense orange		−Molecules 28 05572 i120Orange colour of the solution and
a yellow glow. After addition of HCl:
Yellow solution and orange precipitate		+−Molecules 28 05572 i121The colour of the
solution changes
to dark orange		−−−Molecules 28 05572 i122
Ep FThe colour of the
solution changes to brown, the
formation of a
delicate precipitate		−Molecules 28 05572 i123The appearance of a yellow glow. After addition of HCl: The formation of 3 phases: brick red, orange, black−−Molecules 28 05572 i124No changes were observed−−−Molecules 28 05572 i125
Ep LThe formation of three phases: dark brown, brown and dark burgundy with a delicate
precipitate		−Molecules 28 05572 i126The appearance of a yellow glow. After addition of HCl: Orange colour of the
solution and slight dispersion of
the phases		−−Molecules 28 05572 i127The colour of the
solution changes
to amber-orange		−−−Molecules 28 05572 i128
Hp HThe colour of the
solution changes to orange, the
formation of a
delicate white
precipitate		+Molecules 28 05572 i129Brown colour of the solution and a yellow glow. After addition of HCl: Orange-
yellow-brown colour of the solution and formation of a yellow glow		−−Molecules 28 05572 i130The colour of the
solution changes
to orange		−−−Molecules 28 05572 i131
Hr FrThe colour of the
solution changes to cloudy yellow		−Molecules 28 05572 i132The appearance of a yellow colour. After addition of HCl: The formation of 2 phases: light yellow and intense yellow−−Molecules 28 05572 i133The colour of the
solution changes
to dark yellow		−−−Molecules 28 05572 i134
Lc SPrecipitation of a powdery pink
precipitate		+Molecules 28 05572 i135Lemon colour of the solution. After
addition of HCl: Lemon coloured solution and light pink precipitate		+−Molecules 28 05572 i136Change of colour
of the solution
to lemon		−−−Molecules 28 05572 i137
Mc FThe formation of two phases: dark and light orange−Molecules 28 05572 i138Orange colour of the solution and yellow glow. After addition of HCl: Orange-
yellow colour of the solution and
formation of a yellow glow		−−Molecules 28 05572 i139A change in the
colour tone of the
solution was
observed		−−−Molecules 28 05572 i140
Ob HThe colour of the
solution changes to brown		−Molecules 28 05572 i141Brown-orange colour of the solution and a yellow glow. After addition of HCl:
Orange-brown colour of the solution and formation of a yellow glow		−−Molecules 28 05572 i142The colour of the
solution changes
to orange		−−−Molecules 28 05572 i143
Pm HPrecipitation of a dark maroon solid−Molecules 28 05572 i144Amber colour of the solution and a yellow glow. After addition of HCl: Orange-brown colour of the solution−−Molecules 28 05572 i145The colour of the
solution changes
to orange		−−−Molecules 28 05572 i146
Poa HNo changes were observed−Molecules 28 05572 i147Orange colour of the solution and yellow glow. After addition of HCl: Yellow-
orange colour of the solution and finely
dispersed precipitate		−−Molecules 28 05572 i148The colour of the
solution changes to an intense yellow		−−−Molecules 28 05572 i149
Ps SFormation of a fine white precipitate+Molecules 28 05572 i150Lemon colour of the solution. After
addition of HCl: Lemon coloured solution and white precipitate		−−Molecules 28 05572 i151Precipitation of
a fine precipitate		+−−Molecules 28 05572 i152
Pta LThe colour of the
solution changes to red-orange		−Molecules 28 05572 i153Brown-red colour of the solution.
After addition of HCl: Yellow-brown
colour of the solution and formation of
a fine precipitate		+−Molecules 28 05572 i154The colour of the
solution changes
to orange		−−−Molecules 28 05572 i155
Sg LThe formation of two phases: brown and orange−Molecules 28 05572 i156Brown-red colour of the solution and a
yellow glow. After addition of HCl:
Orange-brown colour of the solution		−−Molecules 28 05572 i157The colour of the
solution changes
to orange		−−−Molecules 28 05572 i158
So RNo changes were observed−Molecules 28 05572 i159Brown-red colour of the solution and a
yellow glow. After addition of HCl:
Amber-orange colour of the solution		−−Molecules 28 05572 i160The appearance of
a jelly-like
consistency		−−−Molecules 28 05572 i161
To FNo changes were observed−Molecules 28 05572 i162Orange colour of the solution and yellow glow. After addition of HCl: Orange
colour of the solution and formation of
a dark precipitate		+−Molecules 28 05572 i163No changes were observed−−−Molecules 28 05572 i164
To LThe formation of two phases: brown and orange−Molecules 28 05572 i165Red-orange colouration and yellow glow. After addition of HCl: Orange-brown
colour of the solution		−−Molecules 28 05572 i166The appearance of an orange glow−−−Molecules 28 05572 i167
To RFormation of two phases: cloudy
yellow and yellow-orange		−Molecules 28 05572 i168Yellow colour of the solution. After
addition of HCl: Lemon yellow colour of the solution		−−Molecules 28 05572 i169Change of colour of the solution
to lemon		−−−Molecules 28 05572 i170
Tp FThe formation of two phases: dark and light orange−Molecules 28 05572 i171Orange colour of the solution and yellow glow. After addition of HCl: Orange
colour of the solution		−−Molecules 28 05572 i172The colour of the
solution changes
to orange		−−−Molecules 28 05572 i173
Ur LNo changes were observed−Molecules 28 05572 i174Orange colour. After addition of HCl: Slight orange colour and dispersed
precipitate formation		+−Molecules 28 05572 i175The colour of the
solution changes
to yellow		−−−Molecules 28 05572 i176
Ur RNo changes were observed−Molecules 28 05572 i177Intense yellow colour. After addition of HCl: The formation of 2 phases: lemon and intense yellow−−Molecules 28 05572 i178Change of colour of the solution to lemon, precipitation of a precipitate++−Molecules 28 05572 i179
Vo RNo changes were observed−Molecules 28 05572 i180Brown-red colour of the solution and a
yellow glow. After addition of HCl:
Amber-orange colour of the solution		−−Molecules 28 05572 i181The colour of the
solution changes
to orange-yellow		−−−Molecules 28 05572 i182
+—present; −—not present; −/+—not obvious. Abbreviations: Alv L—aloe leaves; Am Fr—black chokeberry fruits; Arv H—common mugwort herb; Bv R—beetroot roots; Co F—common marigold flowers; Ea H—field horsetail herb; Ep F—purple coneflower flowers; Ep L—purple coneflower leaves; Hp H—St. John’s wort herb; Hr Fr—sea-buckthorn fruits; Lc S—red lentil seeds; Mc F—chamomile flowers; Ob H—basil herb; Pm H—broadleaf plantain herb; Poa H—common knotgrass herb; Ps S—pea seeds; Pta L—common bracken leaves; Sg L—giant goldenrod leaves; So R—comfrey roots; To F—common dandelion flowers; To L—common dandelion leaves; To R—common dandelion roots; Tp F—red clover flowers; Ur L—nettle leaves; Ur R—nettle roots; Vo R—valerian roots.
Table
Table 4. The results of potassium dichromate test and HCl test (TN—tannins).
Table 4. The results of potassium dichromate test and HCl test (TN—tannins).
MethodPotassium Dichromate TestHCl Test (Phlobatannins)
ExtractObservationTNPhotoObservationTNPhoto
Alv LThe colour of the solution changes
to red		−Molecules 28 05572 i183A colour change of the solution
to yellow was observed		−Molecules 28 05572 i184
Am FrThe colour of the solution changes
to a dark colour		−Molecules 28 05572 i185A change in colour tone
to a brighter red was observed		−Molecules 28 05572 i186
Arv HThe colour of the solution changes
to a dark colour		−Molecules 28 05572 i187A colour change of the solution
to light orange was observed		−Molecules 28 05572 i188
Bv RThe colour of the solution changes
to dark maroon		−Molecules 28 05572 i189A change in the colour of the solution to orange was observed,
the separation of a fine precipitate		−/+Molecules 28 05572 i190
Co FThe appearance of 2 phases was
observed: orange-brown and red		−Molecules 28 05572 i191A change in the colour of the solution to orange-yellow was observed,
precipitation of a precipitate in the upper part of the tube		−/+Molecules 28 05572 i192
Ea HThe colour of the solution changes
to brown-red		−Molecules 28 05572 i193A colour change of the solution
to yellow was observed		−Molecules 28 05572 i194
Ep FThe colour of the solution changes
to a dark colour		−Molecules 28 05572 i195A colour change of the solution
to orange was observed		−Molecules 28 05572 i196
Ep LThe colour of the solution changes
to a dark colour		−Molecules 28 05572 i197A colour change of the solution
to yellow-orange was observed		−Molecules 28 05572 i198
Hp HThe colour of the solution changes
to a dark colour		−Molecules 28 05572 i199A colour change of the solution
to light orange was observed		−Molecules 28 05572 i200
Hr FrThe colour of the solution changes
to orange-brick		−Molecules 28 05572 i201A change in colour tone
to a brighter yellow was observed		−Molecules 28 05572 i202
Lc SThe colour of the solution changes
to intense orange		−Molecules 28 05572 i203Discolouration of the solution
was observed		−Molecules 28 05572 i204
Mc FThe colour of the solution changes
to orange		−Molecules 28 05572 i205A change in the colour tone of
the solution to a bright yellow
was observed		−Molecules 28 05572 i206
Ob HThe colour of the solution changes
to a dark colour		−Molecules 28 05572 i207A colour change of the solution
to orange was observed		−Molecules 28 05572 i208
Pm HThe colour of the solution changes
to a dark colour		−Molecules 28 05572 i209A colour change of the solution
to olive green was observed		−Molecules 28 05572 i210
Poa HThe colour of the solution changes
to brown-orange		−Molecules 28 05572 i211A change in the colour tone of
the solution to bright yellow
was observed		−Molecules 28 05572 i212
Ps SThe colour of the solution changes
to intense orange		−Molecules 28 05572 i213Discolouration of the solution
was observed		−Molecules 28 05572 i214
Pta LThe colour of the solution changes
to a brown-orange colour		−Molecules 28 05572 i215A colour change of the solution
to light orange was observed		−Molecules 28 05572 i216
Sg LThe colour of the solution changes
to a dark colour		−Molecules 28 05572 i217A colour change of the solution
to orange was observed		−Molecules 28 05572 i218
So RThe colour of the solution changes
to a dark colour		−Molecules 28 05572 i219A change in the colour of the solution to light yellow was observed,
the separation of a delicate
precipitate		+Molecules 28 05572 i220
To FThe colour of the solution changes
to dark brown		−Molecules 28 05572 i221A colour change of the solution
to orange-yellow was observed		−Molecules 28 05572 i222
To LThe colour of the solution changes
to a dark colour		−Molecules 28 05572 i223A colour change of the solution
to orange-yellow was observed		−Molecules 28 05572 i224
To RThe colour of the solution changes
to orange		−Molecules 28 05572 i225A change in the colour tone of
the solution to bright yellow
was observed		−Molecules 28 05572 i226
Tp FThe colour of the solution changes
to red-brown		−Molecules 28 05572 i227A colour change of the solution
to light orange was observed		−Molecules 28 05572 i228
Ur LThe colour of the solution changes
to orange-brick red		−Molecules 28 05572 i229A change in colour tone
to a brighter yellow was observed		−Molecules 28 05572 i230
Ur RThe colour of the solution changes
to intense orange		−Molecules 28 05572 i231A change in the colour of the solution to a clear lemon colour was observed−Molecules 28 05572 i232
Vo RThe colour of the solution changes
to red-orange		−Molecules 28 05572 i233Appearance of a maroon precipitate in the upper part of the tube and a change in the colour of the solution to orange+Molecules 28 05572 i234
+—present; −—not present; −/+—not obvious. Abbreviations: Alv L—aloe leaves; Am Fr—black chokeberry fruits; Arv H—common mugwort herb; Bv R—beetroot roots; Co F—common marigold flowers; Ea H—field horsetail herb; Ep F—purple coneflower flowers; Ep L—purple coneflower leaves; Hp H—St. John’s wort herb; Hr Fr—sea-buckthorn fruits; Lc S—red lentil seeds; Mc F—chamomile flowers; Ob H—basil herb; Pm H—broadleaf plantain herb; Poa H—common knotgrass herb; Ps S—pea seeds; Pta L—common bracken leaves; Sg L—giant goldenrod leaves; So R—comfrey roots; To F—common dandelion flowers; To L—common dandelion leaves; To R—common dandelion roots; Tp F—red clover flowers; Ur L—nettle leaves; Ur R—nettle roots; Vo R—valerian roots.
Table
Table 5. The results of NaOH test and H2SO4 test (AC—anthocyanins, CM—coumarins, FL—flavones).
Table 5. The results of NaOH test and H2SO4 test (AC—anthocyanins, CM—coumarins, FL—flavones).
MethodNaOH TestH2SO4 Test
ExtractObservationACCMFLPhotoObservationACFLPhoto
Alv LThe colour of the solution changes to orange−−−Molecules 28 05572 i235The colour of the solution changes to orange++Molecules 28 05572 i236
Am FrAppearance of a fine precipitate, colour change of the precipitate to yellow-brown−−−Molecules 28 05572 i237The colour of the solution changes to a more intense red++Molecules 28 05572 i238
Arv HThe colour of the solution changes to orange−−−Molecules 28 05572 i239The colour of the solution changes to a cloudy
brown-orange		−/+−/+Molecules 28 05572 i240
Bv RThe colour of the solution changes to orange−−−Molecules 28 05572 i241The colour of the solution changes to dark maroon−−Molecules 28 05572 i242
Co FThe colour of the solution changes to orange−−−Molecules 28 05572 i243Change of colour of the
solution to orange and
precipitation of
a fine precipitate		−/+−/+Molecules 28 05572 i244
Ea HThe colour of the solution changes to orange-yellow−−/+−/+Molecules 28 05572 i245Slight turbidity
of the solution, orange colour of solution		−/+−/+Molecules 28 05572 i246
Ep FThe appearance of a yellow glow−−−Molecules 28 05572 i247Turbidity of the solution, cloudy red-brown colour
of solution		−/+−/+Molecules 28 05572 i248
Ep LThe colour of the solution changes to orange-yellow−−/+−/+Molecules 28 05572 i249Turbidity of the solution, brown-orange colour of
solution		−/+−/+Molecules 28 05572 i250
Hp HThe colour of the solution changes to yellow-brown−−/+−/+Molecules 28 05572 i251The colour of the solution changes to cloudy red++Molecules 28 05572 i252
Hr FrThe colour of the solution changes to an intense yellow−++Molecules 28 05572 i253No changes were observed−−Molecules 28 05572 i254
Lc SThe colour of the solution changes to light lemon−−/+−/+Molecules 28 05572 i255Two phases are created: pink and light lemon−−Molecules 28 05572 i256
Mc FThe colour of the solution changes to yellow−++Molecules 28 05572 i257No changes were observed−−Molecules 28 05572 i258
Ob HThe colour of the solution changes to orange−−−Molecules 28 05572 i259Turbidity of the solution, brown-orange colour of
solution		−/+−/+Molecules 28 05572 i260
Pm HThe colour of the solution changes to orange-yellow−−/+−/+Molecules 28 05572 i261No changes were observed,
brown-orange colour
of solution 		−/+−/+Molecules 28 05572 i262
Poa HThe colour of the solution changes to yellow−++Molecules 28 05572 i263The colour of the solution changes to bright orange++Molecules 28 05572 i264
Ps SThe colour of the solution changes to light lemon−−/+−/+Molecules 28 05572 i265The formation of 2 phases: cloudy and light lemon−−Molecules 28 05572 i266
Pta LOrange colour of the solution and the appearance of a fine
precipitate		−−−Molecules 28 05572 i267The colour of the solution changes to orange-yellow++Molecules 28 05572 i268
Sg LThe colour of the solution changes to orange−−−Molecules 28 05572 i269Colour change of
the solution to orange-brown		−/+−/+Molecules 28 05572 i270
So RThe colour of the solution changes to orange−−−Molecules 28 05572 i271The formation of a jelly-like consistency, orange-brown colour of solution−/+−/+Molecules 28 05572 i272
To FThe colour of the solution changes to orange−−−Molecules 28 05572 i273The colour of the solution changes to brown-orange−/+−/+Molecules 28 05572 i274
To LThe colour of the solution changes to orange−−−Molecules 28 05572 i275Precipitation formation, brown-orange colour of
solution		−−Molecules 28 05572 i276
To RThe colour of the solution changes to yellow−++Molecules 28 05572 i277No changes were observed−−Molecules 28 05572 i278
Tp FThe colour of the solution changes to orange-yellow−−/+−/+Molecules 28 05572 i279The colour of the solution changes to cloudy orange++Molecules 28 05572 i280
Ur LChange of colour of the solution to orange-yellow, precipitation of a fine precipitate−−/+−/+Molecules 28 05572 i281The colour of the solution changes to orange++Molecules 28 05572 i282
Ur RThe colour of the solution changes to lemon−−/+−/+Molecules 28 05572 i283No changes were observed−−Molecules 28 05572 i284
Vo RThe colour of the solution changes to orange−−−Molecules 28 05572 i285No changes were observed−−Molecules 28 05572 i286
+—present; −—not present; −/+—not obvious. Abbreviations: Alv L—aloe leaves; Am Fr—black chokeberry fruits; Arv H—common mugwort herb; Bv R—beetroot roots; Co F—common marigold flowers; Ea H—field horsetail herb; Ep F—purple coneflower flowers; Ep L—purple coneflower leaves; Hp H—St. John’s wort herb; Hr Fr—sea-buckthorn fruits; Lc S—red lentil seeds; Mc F—chamomile flowers; Ob H—basil herb; Pm H—broadleaf plantain herb; Poa H—common knotgrass herb; Ps S—pea seeds; Pta L—common bracken leaves; Sg L—giant goldenrod leaves; So R—comfrey roots; To F—common dandelion flowers; To L—common dandelion leaves; To R—common dandelion roots; Tp F—red clover flowers; Ur L—nettle leaves; Ur R—nettle roots; Vo R—valerian roots.
Table
Table 6. The results of aluminium chloride test, ammonium test, ammonia and H2SO4 test, and DNPH tests (FD—flavonoids, VC—Vitamin C).
Table 6. The results of aluminium chloride test, ammonium test, ammonia and H2SO4 test, and DNPH tests (FD—flavonoids, VC—Vitamin C).
MethodAluminium Chloride TestAmmonium TestAmmonia and H2SO4 TestDNPH Test
ExtractObservationFDPhotoObservationFDPhotoObservationFDPhotoObservationVCPhoto
Alv LRed-orange colour of
the solution;
Orange colour of the solution and precipitation of a fine precipitate		−/+Molecules 28 05572 i287The colour of the
solution changes to orange with a
yellow glow		−/+Molecules 28 05572 i288The colour of the
solution changes to
orange		−Molecules 28 05572 i289The colour of the
solution changes to brown-orange		−Molecules 28 05572 i290
Am FrPurple-raspberry colour;
Formation of 2 phases:
red and green		−Molecules 28 05572 i291The colour of the
solution changes to olive green		−Molecules 28 05572 i292The colour of the
solution changes to
orange-amber		−Molecules 28 05572 i293Turbidity of the
solution, change to a lighter colour		−Molecules 28 05572 i294
Arv HGreen-brown colour of the solution;
Orange-yellow colour of the solution		−/+Molecules 28 05572 i295The colour of the
solution changes to olive green		−Molecules 28 05572 i296The colour of the
solution changes to light green		−Molecules 28 05572 i297The colour of the
solution changes to an intense orange		−Molecules 28 05572 i298
Bv RRed colour of the solution;
Formation of 2 phases:
red and orange		−/+Molecules 28 05572 i299The colour of the
solution changes to maroon		−Molecules 28 05572 i300The colour of the
solution changes to
orange		−Molecules 28 05572 i301The colour of the
solution changes to maroon		−Molecules 28 05572 i302
Co FOrange-yellow colour of the solution;
Orange-yellow colour of the solution		−/+Molecules 28 05572 i303The colour of the
solution changes to
orange-yellow		−/+Molecules 28 05572 i304The colour of the
solution changes to
yellow		+Molecules 28 05572 i305The colour of the
solution changes to an
intense red-orange		−Molecules 28 05572 i306
Ea HOrange colour of the
solution;
Yellow colour of the
solution and precipitation of an orange precipitate		−/+Molecules 28 05572 i307The colour of the
solution changes to brown with a yellow glow		−/+Molecules 28 05572 i308The colour of the
solution changes to
yellow		+Molecules 28 05572 i309The colour of the
solution changes to an intense orange		−Molecules 28 05572 i310
Ep FFormation of 2 phases:
yellow-brown and brown;
Formation of 2 phases:
yellow-brown and orange
with a precipitate		−/+Molecules 28 05572 i311The colour of the
solution changes to dark brown with a yellow glow		−/+Molecules 28 05572 i312The colour of the
solution changes to dark brown		−Molecules 28 05572 i313Appearance of a fine white precipitate−/+Molecules 28 05572 i314
Ep LOlive green colour of the solution;
Orange-brown colour of the solution		−/+Molecules 28 05572 i315The colour of the
solution changes to brown with a yellow glow		−/+Molecules 28 05572 i316The colour of the
solution changes to
olive green		−Molecules 28 05572 i317Turbidity of the
solution		−Molecules 28 05572 i318
Hp HYellow-green colour of the solution;
Orange-yellow colour of the solution and
precipitation of a fine
precipitate		−/+Molecules 28 05572 i319The colour of the
solution changes to
orange-yellow		−/+Molecules 28 05572 i320The colour of the
solution changes to
orange		−Molecules 28 05572 i321The colour of the
solution changes to an intense orange		−Molecules 28 05572 i322
Hr FrYellow colour of the
solution;
Yellow colour of the
solution;		−/+Molecules 28 05572 i323The colour of the
solution changes to an intense yellow		+Molecules 28 05572 i324The colour of the
solution changes to
yellow		+Molecules 28 05572 i325The colour of the solution changes to an
intense orange		−Molecules 28 05572 i326
Lc SSalmon-coloured cloudy solution;
Lemon colour of the
solution and precipitation of a delicate pink
precipitate		+Molecules 28 05572 i327The colour of the
solution changes to lemon		−Molecules 28 05572 i328The colour of the
solution changes to lemon		−/+Molecules 28 05572 i329The colour of the solution changes to
yellow, the
appearance of a white
precipitate		+Molecules 28 05572 i330
Mc FYellow colour of the
solution;
Red-yellow/pale yellow
solution		−/+Molecules 28 05572 i331The colour of the
solution changes to
orange-yellow		−/+Molecules 28 05572 i332The colour of the
solution changes to
yellow		+Molecules 28 05572 i333The colour of the
solution changes to
orange		−Molecules 28 05572 i334
Ob HOrange-brown colour of the solution;
Orange-yellow-brown
colour of the solution and precipitation of a fine
precipitate		−/+Molecules 28 05572 i335The colour of the
solution changes to brown with a yellow glow		−/+Molecules 28 05572 i336The colour of the
solution changes to
yellow-brown		−/+Molecules 28 05572 i337Turbidity of the
solution		−Molecules 28 05572 i338
Pm HOrange-brown colour of the solution;
Orange-brown colour of the solution		−/+Molecules 28 05572 i339The colour of the
solution changes to brown with a yellow glow		−/+Molecules 28 05572 i340The colour of the
solution changes to
yellow-brown		−/+Molecules 28 05572 i341Changing the colour of the solution to a darker shade−Molecules 28 05572 i342
Poa HYellow colour of the
solution;
Yellow colour of the
solution and precipitation of a fine precipitate		−/+Molecules 28 05572 i343The colour of the
solution changes to an intense yellow		+Molecules 28 05572 i344The colour of the
solution changes to
yellow		−/+Molecules 28 05572 i345The colour of the
solution changes to
orange		 Molecules 28 05572 i346
Ps SCloudy lemon colour of the solution;
Cloudy lemon colour of the solution and precipitation		+Molecules 28 05572 i347The colour of the
solution changes to lemon		−Molecules 28 05572 i348The solution became clear, no colour change−Molecules 28 05572 i349The colour of the
solution changes to yellow,
the appearance of a white precipitate		+Molecules 28 05572 i350
Pta LOrange colour of the
solution;
Yellow-orange colour of the solution and
precipitation of an orange
precipitate		−/+Molecules 28 05572 i351The colour of the
solution changes to orange		−Molecules 28 05572 i352The colour of the
solution changes to
orange		−Molecules 28 05572 i353The colour of the
solution changes to
orange		−Molecules 28 05572 i354
Sg LOlive green solution and
precipitation;
Formation of 2 phases:
olive green and orange-
yellow, precipitation		−/+Molecules 28 05572 i355The colour of the
solution changes to brown with a yellow glow		−/+Molecules 28 05572 i356The colour of the
solution changes to
yellow-brown		−/+Molecules 28 05572 i357Turbidity of the
solution		−Molecules 28 05572 i358
So RGelatinous brown consistency of the solution;
Formation of 2 phases: brown and yellow, the
solution took on
a jelly-like consistency		−/+Molecules 28 05572 i359The colour of the
solution changes to brown with a yellow glow		−/+Molecules 28 05572 i360The colour of the
solution changes to brown-orange		−Molecules 28 05572 i361The appearance of a jelly-like consistency−Molecules 28 05572 i362
To FBrown-orange colour of the solution;
Brown-orange-yellow
colour of the solution		−/+Molecules 28 05572 i363The colour of the
solution changes to brown with a yellow glow		−/+Molecules 28 05572 i364The colour of the
solution changes to
yellow		+Molecules 28 05572 i365The colour of the
solution changes to
orange-red		−Molecules 28 05572 i366
To LBrown colour of the
solution;
Orange colour of the
solution and precipitation of a brown precipitate		−/+Molecules 28 05572 i367The colour of the
solution changes to brown with a yellow glow		−/+Molecules 28 05572 i368The colour of the
solution changes to
amber		−Molecules 28 05572 i369No changes were
observed		−Molecules 28 05572 i370
To RLemon colour of the
solution;
Lemon colour of the
solution and precipitation of a yellow precipitate		−/+Molecules 28 05572 i371The colour of the
solution changes to yellow		+Molecules 28 05572 i372The colour of the
solution changes to
yellow		+Molecules 28 05572 i373The colour of the
solution changes to an intense orange		−Molecules 28 05572 i374
Tp FOrange-yellow colour of the solution;
Orange-yellow colour of the solution		−/+Molecules 28 05572 i375The colour of the
solution changes to
orange-yellow		−/+Molecules 28 05572 i376The colour of the
solution changes to
yellow		+Molecules 28 05572 i377The colour of the
solution changes to
orange		−Molecules 28 05572 i378
Ur LOlive green colour of the solution;
Orange colour of solution and precipitation		−/+Molecules 28 05572 i379No changes were
observed		−Molecules 28 05572 i380The colour of the
solution changes to
yellow-green		−/+Molecules 28 05572 i381The colour of the
solution changes to
orange-brown		−Molecules 28 05572 i382
Ur RYellow colour of the
solution;
Yellow colour of the
solution		−/+Molecules 28 05572 i383No changes were
observed		−Molecules 28 05572 i384The colour of the
solution changes to lemon		−/+Molecules 28 05572 i385The colour of the
solution changes to an intense orange		−Molecules 28 05572 i386
Vo ROrange-brown colour of the solution;
Brown-yellow colour of the solution		−/+Molecules 28 05572 i387No changes were
observed		−Molecules 28 05572 i388The colour of the
solution changes to
orange		−Molecules 28 05572 i389Changing the colour of the solution to a darker one−Molecules 28 05572 i390
+—present; −—not present; −/+—not obvious. Abbreviations: Alv L—aloe leaves; Am Fr—black chokeberry fruits; Arv H—common mugwort herb; Bv R—beetroot roots; Co F—common marigold flowers; Ea H—field horsetail herb; Ep F—purple coneflower flowers; Ep L—purple coneflower leaves; Hp H—St. John’s wort herb; Hr Fr—sea-buckthorn fruits; Lc S—red lentil seeds; Mc F—chamomile flowers; Ob H—basil herb; Pm H—broadleaf plantain herb; Poa H—common knotgrass herb; Ps S—pea seeds; Pta L—common bracken leaves; Sg L—giant goldenrod leaves; So R—comfrey roots; To F—common dandelion flowers; To L—common dandelion leaves; To R—common dandelion roots; Tp F—red clover flowers; Ur L—nettle leaves; Ur R—nettle roots; Vo R—valerian roots.
Table
Table 7. The results of H2SO4 test, HCl test, ammonia test, NaOH test (QNO—quinones, QNI—quinines).
Table 7. The results of H2SO4 test, HCl test, ammonia test, NaOH test (QNO—quinones, QNI—quinines).
MethodH2SO4 TestHCl TestAmmonia TestNaOH Test
ExtractObservationQNOPhotoObservationQNOPhotoObservationQNOPhotoObservationQNIPhoto
Alv LA change in the colour of the
solution to
dark brown		−Molecules 28 05572 i391A change in the colour of the
solution to yellow with an admixture of orange		−Molecules 28 05572 i392The colour of the solution changes to orange with a yellow glow−Molecules 28 05572 i393The colour of the
solution changes to yellow-orange		−Molecules 28 05572 i394
Am FrA colour change of the solution to dark red+Molecules 28 05572 i395A colour change of the solution to a vivid red−Molecules 28 05572 i396The colour of the solution changes to brown−Molecules 28 05572 i397The colour of the
solution changes to brown with a
yellow glow		−Molecules 28 05572 i398
Arv HA change in the colour of the
solution to
dark brown		−Molecules 28 05572 i399A change in the colour of the
solution to orange with an admixture of yellow		−Molecules 28 05572 i400The colour of the solution changes to olive green−Molecules 28 05572 i401The colour of the
solution changes to yellow-orange		−Molecules 28 05572 i402
Bv RA change in the colour of the
solution to
dark brown		−Molecules 28 05572 i403A colour change of the solution to
maroon		−Molecules 28 05572 i404The colour of the solution changes to red with a yellow glow−Molecules 28 05572 i405The colour of the
solution changes to yellow-orange		−Molecules 28 05572 i406
Co FA change in the colour of the
solution to
dark brown		−Molecules 28 05572 i407A colour change of the solution to
orange with
precipitation		−/+Molecules 28 05572 i408The colour of the solution changes to orange with a yellow glow−Molecules 28 05572 i409The colour of the
solution changes to yellow-orange		−Molecules 28 05572 i410
Ea HA change in the colour of the
solution to brown 		−Molecules 28 05572 i411A colour change of the solution to
yellow 		−Molecules 28 05572 i412The colour of the solution changes to brown-orange with a yellow glow−Molecules 28 05572 i413The colour of the
solution changes to orange with a
yellow glow		−Molecules 28 05572 i414
Ep FA change in the colour of the
solution to dirty brown and the formation of a fine precipitate 		−Molecules 28 05572 i415The colour of the
solution turned
yellow and the
precipitation of a brown precipitate 		−/+Molecules 28 05572 i416The colour of the solution changes to brown with a yellow glow−Molecules 28 05572 i417The colour of the
solution changes to brown with a
yellow glow		−Molecules 28 05572 i418
Ep LA change in the colour of the
solution to brown 		−Molecules 28 05572 i419A colour change of the solution to dirty yellow −Molecules 28 05572 i420The colour of the solution changes to brown with a yellow glow−Molecules 28 05572 i421The colour of the
solution changes to orange with a
yellow glow		−Molecules 28 05572 i422
Hp HA change in the colour of the
solution to
dark brown 		−Molecules 28 05572 i423A colour change of the solution to
orange 		−Molecules 28 05572 i424The colour of the solution changes to orange with a yellow glow−Molecules 28 05572 i425The colour of the
solution changes to yellow		−Molecules 28 05572 i426
Hr FrA change in the colour of the
solution to brown 		−Molecules 28 05572 i427A colour change of the solution to an intense yellow −Molecules 28 05572 i428The colour of the solution changes to neon yellow−Molecules 28 05572 i429The colour of the
solution changes to neon new yellow		−Molecules 28 05572 i430
Lc SA change in the colour of the
solution to brown 		−Molecules 28 05572 i431A change in the colour of the
solution to lemon		−Molecules 28 05572 i432The colour of the solution changes to dirty yellow−Molecules 28 05572 i433The colour of the
solution changes to pale yellow		−Molecules 28 05572 i434
Mc FA change in the colour of the
solution to
dark brown 		−Molecules 28 05572 i435A colour change of the solution to
yellow 		−Molecules 28 05572 i436The colour of the solution changes to orange-yellow−Molecules 28 05572 i437The colour of the
solution changes to yellow		−Molecules 28 05572 i438
Ob HA change in the colour of the
solution to
dark brown 		−Molecules 28 05572 i439A colour change of the solution to
orange-yellow		−Molecules 28 05572 i440The colour of the solution changes to brown with a yellow glow−Molecules 28 05572 i441The colour of the
solution changes to yellow-orange		−Molecules 28 05572 i442
Pm HA change in the colour of the
solution to
dark brown 		−Molecules 28 05572 i443A colour change of the solution to
orange-yellow 		−Molecules 28 05572 i444The colour of the solution changes to brown with a yellow glow−Molecules 28 05572 i445The colour of the
solution changes to yellow-orange		−Molecules 28 05572 i446
Poa HA colour change of the solution to amber−Molecules 28 05572 i447A colour change of the solution to an intense yellow−Molecules 28 05572 i448The colour of the solution changes to an intense
yellow		−Molecules 28 05572 i449The colour of the solution changes to lemon-yellow−Molecules 28 05572 i450
Ps SA change in the colour of the
solution to brown 		−Molecules 28 05572 i451A change in the colour of the
solution to a
delicate lemon		−Molecules 28 05572 i452The colour of the solution changes to light yellow−Molecules 28 05572 i453Change of colour of the solution to
colourless-lemon		−Molecules 28 05572 i454
Pta LA change in the colour of the
solution to
dark brown 		−Molecules 28 05572 i455A colour change of the solution to dirty yellow−Molecules 28 05572 i456The colour of the solution changes to orange−Molecules 28 05572 i457The colour of the
solution changes to dark orange		−Molecules 28 05572 i458
Sg LA change in the colour of the
solution to
dark brown 		−Molecules 28 05572 i459A change in the colour of the
solution to orange with an admixture of yellow		−Molecules 28 05572 i460The colour of the solution changes to brown with a yellow glow−Molecules 28 05572 i461The colour of the
solution changes to yellow-orange		−Molecules 28 05572 i462
So RA change in the colour of the
solution to
dark brown 		−Molecules 28 05572 i463A colour change of the solution to
colourless with
precipitation of an orange precipitate		−/+Molecules 28 05572 i464No changes were observed−Molecules 28 05572 i465The colour of the
solution changes to yellow-orange		−Molecules 28 05572 i466
To FA change in the colour of the
solution to brown 		−Molecules 28 05572 i467A colour change of the solution to
yellow-orange		−Molecules 28 05572 i468The colour of the solution changes to an intense
yellow		−Molecules 28 05572 i469The colour of the
solution changes to orange with a
yellow glow		−Molecules 28 05572 i470
To LA change in the colour of the
solution to
dark brown 		−Molecules 28 05572 i471A colour change of the solution to
yellow-orange with precipitation		−/+Molecules 28 05572 i472The colour of the solution changes to brown with a yellow glow−Molecules 28 05572 i473The colour of the
solution changes to orange with a
yellow glow		−Molecules 28 05572 i474
To RA colour change of the solution to black-brown −Molecules 28 05572 i475A change in the colour of the
solution to a soft orange		−Molecules 28 05572 i476The colour of the solution changes to yellow−Molecules 28 05572 i477The colour of the
solution changes
to yellow		−Molecules 28 05572 i478
Tp FA change in the colour of the
solution to
dark brown 		−Molecules 28 05572 i479A colour change of the solution to
orange-yellow		−Molecules 28 05572 i480The colour of the solution changes to orange-yellow−Molecules 28 05572 i481The colour of the
solution changes
to yellow		−Molecules 28 05572 i482
Ur LA colour change of the solution to bright orange −Molecules 28 05572 i483A colour change of the solution to a dirty orange−Molecules 28 05572 i484No changes were observed−Molecules 28 05572 i485The colour of the
solution changes
to yellow		−Molecules 28 05572 i486
Ur RA change in the colour of the
solution to an
intense orange with an admixture of yellow 		−/+Molecules 28 05572 i487A change in the colour of the
solution to lemon		−Molecules 28 05572 i488No changes were observed−Molecules 28 05572 i489The colour of the
solution changes
to lemon		−Molecules 28 05572 i490
Vo RA change in the colour of the
solution to
dark brown 		−Molecules 28 05572 i491A change in the colour of the
solution to orange with an admixture of brown		−Molecules 28 05572 i492No changes were observed−Molecules 28 05572 i493The colour of the
solution changes to yellow-orange		−Molecules 28 05572 i494
+—present; −—not present; −/+—not obvious. Abbreviations: Alv L—aloe leaves; Am Fr—black chokeberry fruits; Arv H—common mugwort herb; Bv R—beetroot roots; Co F—common marigold flowers; Ea H—field horsetail herb; Ep F—purple coneflower flowers; Ep L—purple coneflower leaves; Hp H—St. John’s wort herb; Hr Fr—sea-buckthorn fruits; Lc S—red lentil seeds; Mc F—chamomile flowers; Ob H—basil herb; Pm H—broadleaf plantain herb; Poa H—common knotgrass herb; Ps S—pea seeds; Pta L—common bracken leaves; Sg L—giant goldenrod leaves; So R—comfrey roots; To F—common dandelion flowers; To L—common dandelion leaves; To R—common dandelion roots; Tp F—red clover flowers; Ur L—nettle leaves; Ur R—nettle roots; Vo R—valerian roots.
Table
Table 8. The presence of cardiac glycosides and resin in botanical extracts—Baljet test and acetone test.
Table 8. The presence of cardiac glycosides and resin in botanical extracts—Baljet test and acetone test.
MethodBaljet TestAcetone Test
ExtractObservationCGSPhotoObservationRNPhoto
Alv LThe colour of the
solution changes
to orange with
a yellow glow		−Molecules 28 05572 i495Formation of 2 phases:
orange with precipitate
and orange		+Molecules 28 05572 i496
Am FrThe colour of the
solution changes
to brown-orange with a yellow glow		−Molecules 28 05572 i497Formation of 2 phases:
light red and cloudy red		+Molecules 28 05572 i498
Arv HThe colour of the
solution changes
to brown-olive		−Molecules 28 05572 i499Formation of 2 phases:
orange and cloudy orange		+Molecules 28 05572 i500
Bv RThe colour of the
solution changes
to red		−Molecules 28 05572 i501A change in the colour shade of the solution−Molecules 28 05572 i502
Co FThe colour of the
solution changes
to brown-orange with a yellow glow		−Molecules 28 05572 i503Formation of 2 phases: cloudy orange and orange+Molecules 28 05572 i504
Ea HThe colour of the
solution changes
to orange with a
yellow glow		−/+Molecules 28 05572 i505Formation of 2 phases:
turbid yellow and orange		+Molecules 28 05572 i506
Ep FThe appearance of a yellow glow on the walls of the tube−Molecules 28 05572 i507Formation of 2 phases:
precipitate
and a clear solution		−/+Molecules 28 05572 i508
Ep LThe colour of the
solution changes
to brown with a
yellow glow		−Molecules 28 05572 i509Formation of 3 phases:
clear solution, precipitate
and orange		−/+Molecules 28 05572 i510
Hp HThe colour of the
solution changes
to yellow		−Molecules 28 05572 i511Formation of 2 phases:
pale orange and pale yellow		−Molecules 28 05572 i512
Hr FrThe colour of the
solution changes
to intense yellow		−Molecules 28 05572 i513A colour change to
light yellow		−Molecules 28 05572 i514
Lc SThe colour of the
solution changes
to yellow		−Molecules 28 05572 i515Formation of 2 phases: cloudy-orange-pink
and pink		+Molecules 28 05572 i516
Mc FThe colour of the
solution changes
to yellow		−Molecules 28 05572 i517Formation of 2 phases:
clear lemon and yellow		−Molecules 28 05572 i518
Ob HThe colour of the
solution changes
to orange with a
yellow glow		−/+Molecules 28 05572 i519Formation of 2 phases:
yellow with precipitate
and orange		+Molecules 28 05572 i520
Pm HThe colour of the
solution changes
to brown-orange with a yellow glow		−Molecules 28 05572 i521Formation of 2 phases: cloudy yellow
and cloudy orange		+Molecules 28 05572 i522
Poa HThe colour of the
solution changes
to yellow		−Molecules 28 05572 i523A change in the colour of the solution to a light lemon
colour		−Molecules 28 05572 i524
Ps SThe colour of the
solution changes
to yellow		−Molecules 28 05572 i525Formation of 2 phases: cloudy white and white+Molecules 28 05572 i526
Pta LThe colour of the
solution changes
to orange with
a yellow glow		−/+Molecules 28 05572 i527Formation of 2 phases:
yellow and cloudy yellow-orange		+Molecules 28 05572 i528
Sg LThe colour of the
solution changes
to brown with
a yellow glow		−Molecules 28 05572 i529Formation of 2 phases:
turbid yellow and orange		+Molecules 28 05572 i530
So RThe colour of the
solution changes
to brown with
a yellow glow		−Molecules 28 05572 i531Formation of 2 phases: cloudy orange
and amber-orange		+Molecules 28 05572 i532
To FThe colour of the
solution changes
to yellow-orange		−/+Molecules 28 05572 i533Formation of 2 phases:
pale yellow
and cloudy orange		+Molecules 28 05572 i534
To LThe colour of the
solution changes
to brown with
a yellow glow		−Molecules 28 05572 i535A change in the colour of the solution to orange−Molecules 28 05572 i536
To RThe colour of the
solution changes
to intense yellow		−Molecules 28 05572 i537A change in the colour of the solution to lemon−Molecules 28 05572 i538
Tp FThe colour of the
solution changes
to yellow		−Molecules 28 05572 i539Formation of 2 phases:
clear lemon and yellow		−Molecules 28 05572 i540
Ur LThe colour of the
solution changes
to orange with
a yellow glow		−Molecules 28 05572 i541A colour change of the
solution to brown-olive		−Molecules 28 05572 i542
Ur RThe colour of the
solution changes
to intense yellow		−Molecules 28 05572 i543Formation of 2 phases:
turbid yellow and yellow		+Molecules 28 05572 i544
Vo RThe colour of the
solution changes
to brown with
a yellow glow		−Molecules 28 05572 i545Formation of 2 phases: cloudy orange
and amber-orange		+Molecules 28 05572 i546
+—present; −—not present; −/+—not obvious. Abbreviations: Alv L—aloe leaves; Am Fr—black chokeberry fruits; Arv H—common mugwort herb; Bv R—beetroot roots; Co F—common marigold flowers; Ea H—field horsetail herb; Ep F—purple coneflower flowers; Ep L—purple coneflower leaves; Hp H—St. John’s wort herb; Hr Fr—sea-buckthorn fruits; Lc S—red lentil seeds; Mc F—chamomile flowers; Ob H—basil herb; Pm H—broadleaf plantain herb; Poa H—common knotgrass herb; Ps S—pea seeds; Pta L—common bracken leaves; Sg L—giant goldenrod leaves; So R—comfrey roots; To F—common dandelion flowers; To L—common dandelion leaves; To R—common dandelion roots; Tp F—red clover flowers; Ur L—nettle leaves; Ur R—nettle roots; Vo R—valerian roots.
Table
Table 9. The presence of glycosides in botanical extracts—Keller–Killiani test, Borntrager’s tests (1), Borntrager’s tests (2), Molisch’s test (additionally: sugars) (GS—glycosides, CGS—cardiac glycosides, CYGS—cyanogenic glycosides, SG—sugars).
Table 9. The presence of glycosides in botanical extracts—Keller–Killiani test, Borntrager’s tests (1), Borntrager’s tests (2), Molisch’s test (additionally: sugars) (GS—glycosides, CGS—cardiac glycosides, CYGS—cyanogenic glycosides, SG—sugars).
MethodKeller–Killiani TestBorntrager’s Tests (1)Borntrager’s Tests (2)Molisch’s Test
ExtractObservationCGSPhotoObservationCYGSPhotoObservationGSSGPhotoObservationGSSGPhoto
Alv LFormation of 3 phases: olive green, orange and brown-red−Molecules 28 05572 i547Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i548Formation of 2 phases: brown-
orange with a
yellow glow
and colourless		−−Molecules 28 05572 i549Formation of 3 phases: cloudy orange, violet-red and colourless++Molecules 28 05572 i550
Am FrFormation of 3 phases:
red, raspberry, and black		−Molecules 28 05572 i551Formation of 2 phases:
orange-pink and
colourless		−Molecules 28 05572 i552Formation of 2 phases: brown-
orange with a
yellow glow
and colourless		−−Molecules 28 05572 i553Appearance of a
raspberry-coloured phase in the upper part of the tube and a black phase in the lower part		−−Molecules 28 05572 i554
Arv HFormation of 3 phases:
brown, orange,
and dark brown		−Molecules 28 05572 i555Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i556Formation of 2 phases: olive green with a glow of yellow
and colourless		−−Molecules 28 05572 i557Formation of 3 phases: cloudy-orange, violet-red and colourless++Molecules 28 05572 i558
Bv RFormation of 3 phases: red, brown-red,
and bloody		−/+Molecules 28 05572 i559Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i560Formation of 2 phases: orange with a yellow glow and
colourless		−−Molecules 28 05572 i561Formation of 2 phases: dark red and green−−Molecules 28 05572 i562
Co FFormation of 4 phases: black, brown, orange, and dark red−/+Molecules 28 05572 i563Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i564Formation of 2 phases: orange with a yellow glow and
colourless		−−Molecules 28 05572 i565Formation of 3 phases: amber, violet-red
and colourless		++Molecules 28 05572 i566
Ea HFormation of 3 phases: olive-brown, yellow, and
orange-brown		−Molecules 28 05572 i567Formation of 2 phases: light yellow and
colourless		−Molecules 28 05572 i568Formation of 2 phases: brown-
orange with a
yellow glow
and colourless		−−Molecules 28 05572 i569Formation of 3 phases: yellow, red-violet
and colourless		++Molecules 28 05572 i570
Ep FFormation of 3 phases:
brown, brick red,
and brown 		−/+Molecules 28 05572 i571Colourless
solution		−Molecules 28 05572 i572Formation of 2 phases: black with a yellow glow and colourless−−Molecules 28 05572 i573The appearance of a brick-red precipitate in the upper part of the
solution and a brown
solution in the bottom of the test tube		−−Molecules 28 05572 i574
Ep LFormation of 3 phases: olive,
orange,
and green-brown		−Molecules 28 05572 i575Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i576Formation of 2 phases: brown with a yellow glow and
colourless		−−Molecules 28 05572 i577The appearance of a
cappuccino-coloured phase in the upper part of the tube and a brown solution in the lower part		−−Molecules 28 05572 i578
Hp HFormation of 3 phases:
orange-red, red, and black-red 		−/+Molecules 28 05572 i579Formation of 2 phases:
orange-pink and
colourless		−Molecules 28 05572 i580Formation of 2 phases: orange with a yellow glow and
colourless		−−Molecules 28 05572 i581Appearance of a cloudy-orange phase with
a slight precipitate
and a violet-red phase		−−Molecules 28 05572 i582
Hr FrFormation of 3 phases:
dirty yellow, orange,
and brown-red 		−Molecules 28 05572 i583Formation of 2 phases: lemon
and
colourless		−Molecules 28 05572 i584Formation of 2 phases:
yellow
and colourless		−−Molecules 28 05572 i585The appearance of a
yellow phase in the
upper part of the test tube, and a violet-brown-red ring below it		−−Molecules 28 05572 i586
Lc SFormation of 3 phases: pale
yellow, soft pink, and brown-red 		−Molecules 28 05572 i587Colourless
solution		−Molecules 28 05572 i588Formation of 2 phases:
lemon
and colourless		−−Molecules 28 05572 i589Formation of 3 phases: cloudy white, red-violet and colourless++Molecules 28 05572 i590
Mc FFormation of 3 phases:
brown,
dirty yellow,
and red-brown		−Molecules 28 05572 i591Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i592Formation of 2 phases: orange with a yellow glow and
colourless		−−Molecules 28 05572 i593Formation of 3 phases: cloudy-yellow, violet-red and beige++Molecules 28 05572 i594
Ob HFormation of 3 phases:
brown, orange, and dark brown		−Molecules 28 05572 i595Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i596Formation of 2 phases: brown with a yellow glow and
colourless		−−Molecules 28 05572 i597Formation of 3 phases: cloudy-yellow-brown, violet-brown and green++Molecules 28 05572 i598
Pm HFormation of 2 phases:
brown and black		−Molecules 28 05572 i599Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i600Formation of 2 phases:
orange with
a yellow glow
and colourless		−−Molecules 28 05572 i601Formation of 2 phases: cloudy olive-brown
and violet-red		−−Molecules 28 05572 i602
Poa HFormation of 3 phases:
pale yellow,
yellow,
and amber 		−Molecules 28 05572 i603Formation of 2 phases: lemon
and
colourless		−Molecules 28 05572 i604Formation of 2 phases:
orange-yellow
and colourless		−−Molecules 28 05572 i605Formation of 3 phases: light brown, dark brown and green++Molecules 28 05572 i606
Ps SFormation of 3 phases:
pale yellow,
soft pink,
and brown-red		−Molecules 28 05572 i607Colourless
solution		−Molecules 28 05572 i608Formation of 2 phases:
pale lemon
and colourless		−−Molecules 28 05572 i609Formation of 3 phases: cloudy white, red-violet and colourless++Molecules 28 05572 i610
Pta LFormation of 3 phases:
brown, orange,
and red-brown		−Molecules 28 05572 i611Formation of 2 phases:
orange-pink and
colourless		−Molecules 28 05572 i612Formation of 2 phases:
orange-red
and colourless		−−Molecules 28 05572 i613Formation of 2 phases: cloudy-yellow
and violet-brown		−−Molecules 28 05572 i614
Sg LFormation of 4 phases:
brown, orange, olive green,
and black		−/+Molecules 28 05572 i615Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i616Formation of 2 phases: brown with a yellow glow and
colourless		−−Molecules 28 05572 i617Formation of 3 phases: cloudy- yellow,
violet-brown
and violet-red		++Molecules 28 05572 i618
So RFormation of 3 phases:
brown, orange, and black		−/+Molecules 28 05572 i619Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i620Formation of 2 phases: brown with a yellow glow and
colourless		−−Molecules 28 05572 i621Formation of 3 phases: brick-orange, violet-red and colourless++Molecules 28 05572 i622
To FFormation of 3 phases:
olive, orange,
and brown-red
−/+Molecules 28 05572 i623Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i624Formation of 2 phases: orange and colourless−−Molecules 28 05572 i625Formation of 2 phases: dirty brown
and black-brown		−−Molecules 28 05572 i626
To LFormation of 3 phases:
orange-brown, red,
and dark brown		+Molecules 28 05572 i627Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i628Formation of 2 phases:
brown with
a yellow glow
and colourless 		−−Molecules 28 05572 i629Formation of 2 phases: brown
and violet-red-brown		−−Molecules 28 05572 i630
To RFormation of 3 phases:
pale yellow,
yellow,
and blood-
hundred red		−Molecules 28 05572 i631Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i632Formation of 2 phases:
yellow
and colourless		−−Molecules 28 05572 i633Formation of 2 phases: cloudy yellow
and purple		−−Molecules 28 05572 i634
Tp FFormation of 3 phases:
brown, orange,
and red-brown		−Molecules 28 05572 i635Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i636Formation of 2 phases:
orange
and colourless		−−Molecules 28 05572 i637Formation of 3 phases: cloudy-orange, violet-red and colourless++Molecules 28 05572 i638
Ur LFormation of 4 phases: brown,
brown-red,
orange,
and yellow		+Molecules 28 05572 i639Formation of 2 phases: light orange and
colourless		−Molecules 28 05572 i640Formation of 2 phases:
olive-brown
and colourless 		−−Molecules 28 05572 i641Formation of 3 phases: light brown, pink-purple and green++Molecules 28 05572 i642
Ur RFormation of 3 phases:
lemon, yellow, and
orange-yellow 		−Molecules 28 05572 i643Formation of 2 phases: light lemon and
colourless		−Molecules 28 05572 i644Formation of 2 phases:
lemon
and colourless 		−−Molecules 28 05572 i645Formation of 3 phases: yellow, purple-brown and green++Molecules 28 05572 i646
Vo RFormation of 3 phases: orange-amber, maroon,
and brown-red
+Molecules 28 05572 i647Formation of 2 phases: yellow
and
colourless		−Molecules 28 05572 i648Formation of 2 phases: brown with a yellow glow and
colourless 		−−Molecules 28 05572 i649Formation of 2 phases: cloudy brown
and purple-red		−−Molecules 28 05572 i650
+—present; −—not present; −/+—not obvious. Abbreviations: Alv L—aloe leaves; Am Fr—black chokeberry fruits; Arv H—common mugwort herb; Bv R—beetroot roots; Co F—common marigold flowers; Ea H—field horsetail herb; Ep F—purple coneflower flowers; Ep L—purple coneflower leaves; Hp H—St. John’s wort herb; Hr Fr—sea-buckthorn fruits; Lc S—red lentil seeds; Mc F—chamomile flowers; Ob H—basil herb; Pm H—broadleaf plantain herb; Poa H—common knotgrass herb; Ps S—pea seeds; Pta L—common bracken leaves; Sg L—giant goldenrod leaves; So R—comfrey roots; To F—common dandelion flowers; To L—common dandelion leaves; To R—common dandelion roots; Tp F—red clover flowers; Ur L—nettle leaves; Ur R—nettle roots; Vo R—valerian roots.
Table
Table 10. The presence of sugars in botanical extracts—Fehling’s test, Benedict’s test, Selwinoff’s test, Barfoed’s test (SG—sugars).
Table 10. The presence of sugars in botanical extracts—Fehling’s test, Benedict’s test, Selwinoff’s test, Barfoed’s test (SG—sugars).
MethodFehling’s TestBenedict’s TestSelwinoff’s TestBarfoed’s Test
ExtractObservationSGPhotoObservationSGPhotoObservationSGPhotoObservationSGPhoto
Alv LA colour change to brick-brown−Molecules 28 05572 i651Intense olive colour;
Orange-brick colour +
red precipitate		+Molecules 28 05572 i652The colour of the solution changes to orange−Molecules 28 05572 i653Green colour of the
solution;
Dark green colour
of the solution		−Molecules 28 05572 i654
Am FrA colour change to dark amber−Molecules 28 05572 i655Intense green colour + fine precipitate;
Olive colour + red precipitate		+Molecules 28 05572 i656The colour of the solution changes to bright red+Molecules 28 05572 i657Green-blue solution + precipitation;
Green-blue solution + black precipitate		−Molecules 28 05572 i658
Arv HA colour change to dark green−Molecules 28 05572 i659Intense colouring;
Olive colour +
brick red precipitate		+Molecules 28 05572 i660The colour of the solution changes to brown-orange−Molecules 28 05572 i661Green colour +
brick red precipitate;
Green colour +
brick red precipitate		+Molecules 28 05572 i662
Bv RA colour change to dirty brown−Molecules 28 05572 i663Olive colour;
Cloudy orange solution +
orange precipitate		+Molecules 28 05572 i664The colour of the solution changes to orange-brick+Molecules 28 05572 i665Dark green colour;
Green solution +
precipitate		−Molecules 28 05572 i666
Co FA colour change to dark yellow-orange−Molecules 28 05572 i667Green-yellow colour;
Orange-yellow colour +
red-orange precipitate		+Molecules 28 05572 i668The colour of the solution changes to orange−Molecules 28 05572 i669Green-cloudy colour
of the solution;
Green colour of the
solution + precipitate		−Molecules 28 05572 i670
Ea HA colour change to green with a dark maroon glow at the bottom−Molecules 28 05572 i671Intense green solution;
Orange solution +
orange precipitate		+Molecules 28 05572 i672No changes were observed−Molecules 28 05572 i673Dark green colour +
slight precipitate;
Green colour of the
solution + precipitate		−Molecules 28 05572 i674
Ep FA colour change to dark brown−Molecules 28 05572 i675Dirty olive green;
Brown-orange solution +
orange precipitate		+Molecules 28 05572 i676The colour of the solution changes to orange−Molecules 28 05572 i677Cloudy olive solution;
Cloudy olive solution		−Molecules 28 05572 i678
Ep LA colour change to dark green−Molecules 28 05572 i679Intense green solution;
Olive green +
orange precipitate		+Molecules 28 05572 i680The colour of the solution changes to orange−Molecules 28 05572 i681Cloudy green solution + fine precipitate;
Cloudy green solution + fine precipitate		−Molecules 28 05572 i682
Hp HA colour change to brick red−Molecules 28 05572 i683Green solution;
Brown-orange colour +
brick red precipitate		+Molecules 28 05572 i684The colour of the solution changes to red-orange+Molecules 28 05572 i685Intense green colour of the precipitate solution;
Intense green colour + brick-hundred-brown precipitate		−Molecules 28 05572 i686
Hr FrA colour change to intense green with a dark maroon glow at the bottom of the tube−Molecules 28 05572 i687Intense light green solution;
Light olive green +
reddish-brown precipitate		+Molecules 28 05572 i688The colour of the solution changes to a vivid yellow-orange−Molecules 28 05572 i689Green colour +
precipitation of a delicate precipitate;
Green colour +
precipitation		−Molecules 28 05572 i690
Lc SA colour change to navy blue−Molecules 28 05572 i691Bright turquoise solution;
Green solution		−Molecules 28 05572 i692The colour of the solution changes to cloudy-
colourless		−Molecules 28 05572 i693Light blue solution;
Blue colour of the solution + white precipitate		−Molecules 28 05572 i694
Mc FA colour change to green−Molecules 28 05572 i695Intense green;
Cloudy orange-brown
solution + orange precipitate		+Molecules 28 05572 i696The colour of the solution changes to olive green−Molecules 28 05572 i697Green colour
of the solution;
Green colour
of the solution + green
precipitate		−Molecules 28 05572 i698
Ob HA colour change to green−Molecules 28 05572 i699Intense green;
Olive colour +
brick red precipitate		+Molecules 28 05572 i700The colour of the solution changes to brown-orange−Molecules 28 05572 i701Blue-green colour + dark green precipitate;
Green-turquoise colour + brick-hundred-brown precipitate		−Molecules 28 05572 i702
Pm HA colour change to green with a dark maroon glow at the bottom−Molecules 28 05572 i703Intense green;
Olive colour +
brick red precipitate		+Molecules 28 05572 i704The colour of the solution changes to brown−Molecules 28 05572 i705Dark green solution + precipitate;
Dark green solution + dark precipitate		−Molecules 28 05572 i706
Poa HA colour change to intense green−Molecules 28 05572 i707Intense green;
Olive colour + red precipitate		+Molecules 28 05572 i708The colour of the solution changes to orange with the formation of a
precipitate		−Molecules 28 05572 i709Green colour of the
solution + precipitation;
Green colour of the
solution + precipitation		−Molecules 28 05572 i710
Ps SA colour change to blue with a dark green glow−Molecules 28 05572 i711Light turquoise solution;
Intense green		−Molecules 28 05572 i712Change of colour of the solution to cloudy powder pink−Molecules 28 05572 i713Blue colour of the solution;
Gelatinous, blue
consistency of the
solution		−Molecules 28 05572 i714
Pta LA colour change to bloody red−Molecules 28 05572 i715Green colouration;
Brown-orange colour +
red precipitate		+Molecules 28 05572 i716The colour of the solution changes to orange−Molecules 28 05572 i717Green colour of the
solution + brick-red
precipitate;
Green-turquoise colour + brick red precipitate		+Molecules 28 05572 i718
Sg LA colour change to a dark olive green−Molecules 28 05572 i719Intense green;
Olive-brown colour +
red precipitate		+Molecules 28 05572 i720The colour of the solution changes to brown with the formation of a
precipitate		−Molecules 28 05572 i721Dark green colour +
precipitate;
Green colour + dark olive precipitate		−Molecules 28 05572 i722
So RA colour change to a dirty olive green−Molecules 28 05572 i723The appearance of a blue-green colour;
Olive-orange solution +
orange precipitate		+Molecules 28 05572 i724The colour of the solution changes to orange with the formation of a
precipitate		−Molecules 28 05572 i725Turquoise colour, black precipitate, gelatinous
solution form;
Turquoise colour + black precipitate		−Molecules 28 05572 i726
To FA colour change to orange-amber−Molecules 28 05572 i727Intense green;
Cloudy orange solution +
orange precipitate		+Molecules 28 05572 i728The colour of the solution changes to orange-amber−Molecules 28 05572 i729Green colour of the
solution + precipitation of a green precipitate;
Green colour of the
solution green-brown precipitate		−Molecules 28 05572 i730
To LA colour change to a dirty olive green−Molecules 28 05572 i731Intense green;
Cloudy orange solution +
orange precipitate		+Molecules 28 05572 i732The colour of the solution changes to orange-amber−Molecules 28 05572 i733Cloudy green solution + fine precipitate;
Green solution + green precipitate		−Molecules 28 05572 i734
To RA colour change to brick red−Molecules 28 05572 i735Green +
cloudy colour of the solution + precipitate		+Molecules 28 05572 i736The colour of the solution changes to orange−Molecules 28 05572 i737Turquoise solution + white precipitate;
Turquoise colour + brick red precipitate		+Molecules 28 05572 i738
Tp FA colour change to green−Molecules 28 05572 i739Intense green;
Yellow-brown colour +
red precipitate		+Molecules 28 05572 i740The colour of the solution changes to orange-amber−Molecules 28 05572 i741Green/cloudy solution;
Green solution +
precipitate		−Molecules 28 05572 i742
Ur LA colour change to intense green−Molecules 28 05572 i743Bottle green;
Olive colour +
red-orange precipitate		+Molecules 28 05572 i744The colour of the solution changes to orange-amber−Molecules 28 05572 i745Green colour of the
solution + precipitation of a delicate precipitate;
Turquoise/green colour + precipitation		−Molecules 28 05572 i746
Ur RA colour change to blue with a dark maroon glow at the bottom−Molecules 28 05572 i747Green solution;
Cloudy orange solution +
orange precipitate		+Molecules 28 05572 i748The colour of the solution changes to orange−Molecules 28 05572 i749Turquoise solution + white precipitate;
Turquoise colour + white-brick precipitate		−Molecules 28 05572 i750
Vo RA colour change to a dirty olive green−Molecules 28 05572 i751Intense green;
Dirty olive solution +
precipitate		+Molecules 28 05572 i752No changes were observed−Molecules 28 05572 i753Green colour
of the solution +
slight green precipitate;
Green colour of the
solution + green
precipitate		−Molecules 28 05572 i754
+—present; −—not present; −/+—not obvious. Abbreviations: Alv L—aloe leaves; Am Fr—black chokeberry fruits; Arv H—common mugwort herb; Bv R—beetroot roots; Co F—common marigold flowers; Ea H—field horsetail herb; Ep F—purple coneflower flowers; Ep L—purple coneflower leaves; Hp H—St. John’s wort herb; Hr Fr—sea-buckthorn fruits; Lc S—red lentil seeds; Mc F—chamomile flowers; Ob H—basil herb; Pm H—broadleaf plantain herb; Poa H—common knotgrass herb; Ps S—pea seeds; Pta L—common bracken leaves; Sg L—giant goldenrod leaves; So R—comfrey roots; To F—common dandelion flowers; To L—common dandelion leaves; To R—common dandelion roots; Tp F—red clover flowers; Ur L—nettle leaves; Ur R—nettle roots; Vo R—valerian roots.
Table
Table 11. The antioxidant activity of botanical extracts—DPPH assay, ABTS assay, FRAP assay.
Table 11. The antioxidant activity of botanical extracts—DPPH assay, ABTS assay, FRAP assay.
MethodAntioxidant Activity—DDPHAntioxidant Activity—ABTSAntioxidant Activity—FRAPAntioxidant Activity—DDPHAntioxidant Activity—ABTS
ExtractµM Trolox·mL−1Inhibition Ratio (%)
Alv L0.73 ± 0.090.86 ± 0.141.38 ± 0.0412.71 ± 0.020.74 ± 0.12
Am Fr3.99 ± 0.1410.94 ± 1.638.73 ± 0.116.60 ± 0.000.91 ± 0.14
Arv H1.60 ± 0.023.45 ± 0.375.60 ± 0.0128.12 ± 0.002.95 ± 0.32
Bv R0.83 ± 0.013.17 ± 0.353.26 ± 0.0614.11 ± 0.002.65 ± 0.30
Co F0.97 ± 0.072.59 ± 0.283.31 ± 0.1116.53 ± 0.012.16 ± 0.24
Ea H0.72 ± 0.061.50 ± 0.222.58 ± 0.0812.55 ± 0.011.25 ± 0.18
Ep F4.23 ± 0.2015.54 ± 1.4112.41 ± 0.157.02 ± 0.001.29 ± 0.12
Ep L1.58 ± 0.1719.00 ± 1.4115.28 ± 0.112.37 ± 0.001.58 ± 0.12
Hp H4.55 ± 0.3312.67 ± 0.818.90 ± 0.117.58 ± 0.011.08 ± 0.07
Hr Fr1.78 ± 0.051.84 ± 0.163.64 ± 0.0131.48 ± 0.011.53 ± 0.14
Lc S0.14 ± 0.021.90 ± 0.140.40 ± 0.032.00 ± 0.001.58 ± 0.12
Mc F0.92 ± 0.082.82 ± 0.433.27 ± 0.0315.78 ± 0.012.36 ± 0.36
Ob H2.48 ± 0.234.03 ± 0.8111.74 ± 0.373.95 ± 0.000.34 ± 0.07
Pm H1.79 ± 0.052.53 ± 0.335.56 ± 0.1031.58 ± 0.012.17 ± 0.28
Poa H0.65 ± 0.086.45 ± 0.432.70 ± 0.0711.22 ± 0.015.37 ± 0.36
Ps S0.15 ± 0.014.26 ± 0.330.43 ± 0.012.23 ± 0.003.55 ± 0.27
Pta L9.57 ± 0.856.33 ± 0.8120.25 ± 0.4716.36 ± 0.010.54 ± 0.07
Sg L3.41 ± 0.305.76 ± 0.819.25 ± 0.225.58 ± 0.010.48 ± 0.07
So R1.37 ± 0.195.35 ± 0.615.76 ± 0.0623.65 ± 0.034.47 ± 0.51
To F0.90 ± 0.034.09 ± 0.292.71 ± 0.0115.46 ± 0.013.42 ± 0.25
To L2.61 ± 0.338.64 ± 1.416.62 ± 0.474.18 ± 0.010.72 ± 0.12
To R0.43 ± 0.050.81 ± 0.160.97 ± 0.047.12 ± 0.010.67 ± 0.14
Tp F1.21 ± 0.143.45 ± 0.514.51 ± 0.1020.76 ± 0.022.89 ± 0.42
Ur L0.14 ± 0.011.15 ± 0.081.09 ± 0.022.09 ± 0.000.96 ± 0.07
Ur R0.15 ± 0.023.74 ± 0.220.82 ± 0.022.33 ± 0.003.12 ± 0.18
Vo R0.76 ± 0.062.36 ± 0.352.43 ± 0.0612.94 ± 0.011.97 ± 0.30
Abbreviations: Alv L—aloe leaves; Am Fr—black chokeberry fruits; Arv H—common mugwort herb; Bv R—beetroot roots; Co F—common marigold flowers; Ea H—field horsetail herb; Ep F—purple coneflower flowers; Ep L—purple coneflower leaves; Hp H—St. John’s wort herb; Hr Fr—sea-buckthorn fruits; Lc S—red lentil seeds; Mc F—chamomile flowers; Ob H—basil herb; Pm H—broadleaf plantain herb; Poa H—common knotgrass herb; Ps S—pea seeds; Pta L—common bracken leaves; Sg L—giant goldenrod leaves; So R—comfrey roots; To F—common dandelion flowers; To L—common dandelion leaves; To R—common dandelion roots; Tp F—red clover flowers; Ur L—nettle leaves; Ur R—nettle roots; Vo R—valerian roots.
Table
Table 12. The presence of plant hormones in botanical extracts (μg∙mL−1).
Table 12. The presence of plant hormones in botanical extracts (μg∙mL−1).
MethodABABAGA3IAAJASAZ
Alv L0.84 ± 0.000.10 ± 0.0087.48 ± 0.000.28 ± 0.00tata0.04 ± 0.00
Am Frta0.03 ± 0.0081.11 ± 0.000.81 ± 0.00tatata
Arv H1.00 ± 0.000.08 ± 0.0029.07 ± 0.00tata0.02 ± 0.00ta
Bv R0.34 ± 0.000.23 ± 0.00160.21 ± 0.000.91 ± 0.00tata0.10 ± 0.00
Co F0.35 ± 0.00ta185.71 ± 0.000.97 ± 0.000.03 ± 0.00tata
Ea Htata168.30 ± 0.001.24 ± 0.00ta0.12 ± 0.00ta
Ep F1.23 ± 0.000.13 ± 0.00319.23 ± 0.002.06 ± 0.00tatata
Ep L0.11 ± 0.000.09 ± 0.0087.90 ± 0.000.48 ± 0.00tatata
Hp H1.00 ± 0.00ta72.19 ± 0.000.34 ± 0.00tata0.09 ± 0.09
Hr Frtata66.91 ± 0.001.93 ± 0.000.05 ± 0.000.05 ± 0.00ta
Lc Sta0.01 ± 0.00101.80 ± 0.001.05 ± 0.00ta0.15 ± 0.00ta
Mc F1.50 ± 0.000.01 ± 0.00125.69 ± 0.001.50 ± 0.00tatata
Ob H1.07 ± 0.000.30 ± 0.0094.80 ± 0.000.72 ± 0.00tata0.05 ± 0.00
Pm H0.70 ± 0.000.28 ± 0.00343.92 ± 0.002.07 ± 0.00tatata
Poa Htata162.40 ± 0.001.26 ± 0.000.04 ± 0.000.11 ± 0.00ta
Ps Sta0.10 ± 0.0087.57 ± 0.002.71 ± 0.00tatata
Pta Lta0.07 ± 0.0056.33 ± 0.00tatatata
Sg L0.20 ± 0.00ta359.85 ± 0.000.58 ± 0.00tatata
So R0.15 ± 0.000.03 ± 0.00144.98 ± 0.000.43 ± 0.00tata0.20 ± 0.00
To F0.49 ± 0.000.09 ± 0.00134.40 ± 0.001.13 ± 0.00tata0.21 ± 0.00
To L0.64 ± 0.000.45 ± 0.0088.62 ± 0.001.02 ± 0.00tata0.17 ± 0.00
To R0.85 ± 0.000.48 ± 0.00325.19 ± 0.002.00 ± 0.00tata0.05 ± 0.00
Tp F1.36 ± 0.010.32 ± 0.0076.90 ± 0.001.36 ± 0.010.01 ± 0.00tata
Ur Ltata324.83 ± 0.000.70 ± 0.00tatata
Ur Rtata359.47 ± 0.010.57 ± 0.00tatata
Vo R0.30 ± 0.000.11 ± 0.0085.55 ± 0.000.77 ± 0.00tatata
ta—trace amounts. Abbreviations: Alv L—aloe leaves; Am Fr—black chokeberry fruits; Arv H—common mugwort herb; Bv R—beetroot roots; Co F—common marigold flowers; Ea H—field horsetail herb; Ep F—purple coneflower flowers; Ep L—purple coneflower leaves; Hp H—St. John’s wort herb; Hr Fr—sea-buckthorn fruits; Lc S—red lentil seeds; Mc F—chamomile flowers; Ob H—basil herb; Pm H—broadleaf plantain herb; Poa H—common knotgrass herb; Ps S—pea seeds; Pta L—common bracken leaves; Sg L—giant goldenrod leaves; So R—comfrey roots; To F—common dandelion flowers; To L—common dandelion leaves; To R—common dandelion roots; Tp F—red clover flowers; Ur L—nettle leaves; Ur R—nettle roots; Vo R—valerian roots.
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Godlewska, K.; Pacyga, P.; Najda, A.; Michalak, I. Investigation of Chemical Constituents and Antioxidant Activity of Biologically Active Plant-Derived Natural Products. Molecules 2023, 28, 5572. https://doi.org/10.3390/molecules28145572

AMA Style

Godlewska K, Pacyga P, Najda A, Michalak I. Investigation of Chemical Constituents and Antioxidant Activity of Biologically Active Plant-Derived Natural Products. Molecules. 2023; 28(14):5572. https://doi.org/10.3390/molecules28145572

Chicago/Turabian Style

Godlewska, Katarzyna, Paweł Pacyga, Agnieszka Najda, and Izabela Michalak. 2023. "Investigation of Chemical Constituents and Antioxidant Activity of Biologically Active Plant-Derived Natural Products" Molecules 28, no. 14: 5572. https://doi.org/10.3390/molecules28145572

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