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Analysis and Identification of Natural Product Extracts for Use in Medicine, Public Health and Agriculture

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Natural Products Chemistry".

Deadline for manuscript submissions: closed (15 November 2023) | Viewed by 19979

Special Issue Editors


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Guest Editor
CAMAG Scientific, Inc., 515 Cornelius Harnett Drive, Wilmington, NC 28401, USA
Interests: natural products; quality control of medicinal plants; HPTLC; HPLC; isolation and structure elucidation; NMR; MS

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Guest Editor
Agricultural Research Service, U.S. Department of Agriculture, Natural Products Utilization Research Unit, P.O. Box 1848, University, MS 38677, USA
Interests: natural products; insecticides; fungicides; herbicides from natural sources; HPLC; isolation and structure elucidation; NMR; MS

Special Issue Information

Dear Colleagues,

Natural products have been used as medicines and agrochemicals for centuries. Folk medicine, which represents immeasurable human knowledge transferred between generations, has facilitated the development of new research areas and technologies; these have furthered our understanding of the chemistry of diverse living organisms and the pharmacological properties of different preparations and pure molecules. Natural products are an invaluable source of biologically active compounds used to treat various diseases.

This Special Issue welcomes original research papers, short communications and review articles; emphasis should be on the identification of natural compounds from any natural source; the isolation and structure elucidation of minor or bioactive compounds from plants, microbes and marine organisms; bioassay-guided fractionation; structure–activity relationships; the scale-up of the purification process; the synthesis of natural product analogs; the development and/or validation of analytical methods to assess the quality of herbal drugs and botanical dietary supplements, as well as agrochemicals; and templates that can be used to develop commercial products. 

Dr. Wilmer Perera
Dr. Kumudini M. Meepagala
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • natural products
  • bioactive compounds
  • isolation
  • purification
  • scale-up process
  • synthesis of natural product analogs
  • quality control of medicinal plants

Published Papers (9 papers)

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Research

Jump to: Review

11 pages, 1306 KiB  
Article
Antifungal and Phytotoxic Activities of Isolated Compounds from Helietta parvifolia Stems
by Victor Pena Ribeiro, Joanna Bajsa-Hirschel, Prabin Tamang, Kumudini Meepagala and Stephen O. Duke
Molecules 2023, 28(23), 7930; https://doi.org/10.3390/molecules28237930 - 04 Dec 2023
Viewed by 767
Abstract
The identification of natural and environmentally friendly pesticides is a key area of interest for the agrochemical industry, with many potentially active compounds being sourced from numerous plant species. In this study, we report the bioassay-guided isolation and identification of phytotoxic and antifungal [...] Read more.
The identification of natural and environmentally friendly pesticides is a key area of interest for the agrochemical industry, with many potentially active compounds being sourced from numerous plant species. In this study, we report the bioassay-guided isolation and identification of phytotoxic and antifungal compounds from the ethyl acetate extract of Helietta parvifolia stems. We identified eight compounds, consisting of two coumarins and six alkaloids. Among these, a new alkaloid, 2-hydroxy-3,6,7-trimethoxyquinoline-4-carbaldehyde (6), was elucidated, along with seven known compounds. The phytotoxicity of purified compounds was evaluated, and chalepin (4) was active against Agrostis stolonifera at 1 mM with 50% inhibition of seed germination and it reduced Lemna pausicotata (duckweed) growth by 50% (IC50) at 168 μM. Additionally, we evaluated the antifungal activity against the fungal plant pathogen Colletotrichum fragariae using a thin-layer chromatography bioautography assay, which revealed that three isolated furoquinoline alkaloids (flindersiamine (3), kokusagenine (7), and maculine (8)) among the isolated compounds had the strongest inhibitory effects on the growth of C. fragariae at all tested concentrations. Our results indicate that these active natural compounds, i.e., (3), (4), (7), and (8), could be scaffolds for the production of more active pesticides with better physicochemical properties. Full article
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27 pages, 1566 KiB  
Article
Gas Chromatography–Mass Spectrometry Profiling of Volatile Metabolites Produced by Some Bacillus spp. and Evaluation of Their Antibacterial and Antibiotic Activities
by Moldir Koilybayeva, Zhanserik Shynykul, Gulbaram Ustenova, Krzysztof Waleron, Joanna Jońca, Kamilya Mustafina, Akerke Amirkhanova, Yekaterina Koloskova, Raushan Bayaliyeva, Tamila Akhayeva, Mereke Alimzhanova, Aknur Turgumbayeva, Gulden Kurmangaliyeva, Aigerim Kantureyeva, Dinara Batyrbayeva and Zhazira Alibayeva
Molecules 2023, 28(22), 7556; https://doi.org/10.3390/molecules28227556 - 12 Nov 2023
Cited by 2 | Viewed by 1915
Abstract
Bacillus species produce different classes of antimicrobial and antioxidant substances: peptides or proteins with different structural compositions and molecular masses and a broad range of volatile organic compounds (VOCs), some of which may serve as biomarkers for microorganism identification. The aim of this [...] Read more.
Bacillus species produce different classes of antimicrobial and antioxidant substances: peptides or proteins with different structural compositions and molecular masses and a broad range of volatile organic compounds (VOCs), some of which may serve as biomarkers for microorganism identification. The aim of this study is the identification of biologically active compounds synthesized by five Bacillus species using gas chromatography coupled to mass spectrometry (GC–MS). The current study profoundly enhances the knowledge of antibacterial and antioxidant metabolites ensuring the unambiguous identification of VOCs produced by some Bacillus species, which were isolated from vegetable samples of potato, carrot, and tomato. Phylogenetic and biochemical studies were used to identify the bacterial isolates after culturing. Phylogenetic analysis proved that five bacterial isolates BSS12, BSS13, BSS16, BSS21, and BSS25 showed 99% nucleotide sequence similarities with Bacillus safensis AS-08, Bacillus cereus WAB2133, Bacillus acidiproducens NiuFun, Bacillus toyonesis FORT 102, and Bacillus thuringiensis F3, respectively. The crude extract was prepared from bacterial isolates to assess the antibiotic resistance potency and the antimicrobial potential against various targeted multidrug-resistant strains, including yeast strains such as Candida albicans, Candida krusei, and bacterial strains of Enterococcus hirae, Escherichia coli, Klebsiella aerogenes, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus group B, Streptococcus mutans, Shigella sonnei, Salmonella enteritidis, Serratia marcescens, Pseudomonas aeruginosa, and Proteus vulgaris. GC–MS analysis of bacterial strains found that VOCs from Bacillus species come in a variety of chemical forms, such as ketones, alcohols, terpenoids, alkenes, etc. Overall, 69 volatile organic compounds were identified from five Bacillus species, and all five were found to share different chemical classes of volatile organic components, which have a variety of pharmacological applications. However, eight antibacterial compounds with different concentrations were commonly found in all five species: acetoin, acetic acid, butanoic acid, 2-methyl-, oxime-, methoxy-phenyl, phenol, 1,2-benzenedicarboxylic acid, bis(2-methylpropyl) ester, nonanoic acid, and hexadecanoic acid, methyl. The present study has demonstrated that bacterial isolates BSS25, BSS21, and BSS16 display potent inhibitory effects against Candida albicans, while BSS25, BSS21, and BSS13 exhibit the ability to restrain the growth and activity of Candida krusei. Notably, BSS25 and BSS21 are the only isolates that demonstrate substantial inhibitory activity against Klebsiella aerogenes. This disparity in inhibitory effects could be attributed to the higher concentrations of acetoin in BSS25 and BSS21, whereas BSS16 and BSS13 have relatively elevated levels of butanoic acid, 2-methyl-. Certainly, the presence of acetoin and butanoic acid, 2-methyl-, contributes to the enhanced antibacterial potential of these bacterial strains, in conjunction with other organic volatile compounds and peptides, among other factors. The biology and physiology of Bacillus can be better understood using these results, which can also be used to create novel biotechnological procedures and applications. Moreover, because of its exceptional ability to synthesize and produce a variety of different antibacterial compounds, Bacillus species can serve as natural and universal carriers for antibiotic compounds in the form of probiotic cultures and strains to fight different pathogens, including mycobacteria. Full article
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14 pages, 4049 KiB  
Article
Use of Germination to Enhance Resveratrol Content and Its Anti-Inflammatory Activity in Lipopolysaccharide-Stimulated RAW264.7 Cells
by Chaiwat Monmai, Jin-Suk Kim and So-Hyeon Baek
Molecules 2023, 28(13), 4898; https://doi.org/10.3390/molecules28134898 - 21 Jun 2023
Cited by 3 | Viewed by 933
Abstract
Inflammation is triggered by a variety of danger signals and is now a worldwide concern. Resveratrol, a natural nonflavonoid polyphenol found in naturally consumed plants and foods, has a wide spectrum of bioactive potency. We successfully generated resveratrol-enriched rice by introducing the resveratrol [...] Read more.
Inflammation is triggered by a variety of danger signals and is now a worldwide concern. Resveratrol, a natural nonflavonoid polyphenol found in naturally consumed plants and foods, has a wide spectrum of bioactive potency. We successfully generated resveratrol-enriched rice by introducing the resveratrol biosynthesis gene into Dongjin rice. In this study, resveratrol- and piceid-enriched rice (DJ526) was investigated for its anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW264.7 cells compared to normal rice (DJ). In addition, the 5-day-old germinated DJ526 (DJ526_5) was tested for its anti-inflammatory effects. The piceid and resveratrol amounts increased in DJ526_5 by germination. Treatment of LPS-stimulated RAW264.7 cells with resveratrol-enriched rice seed extracts (DJ526_0 and DJ526_5) significantly decreased the production of nitric oxide (NO) and the inflammatory mediator prostaglandin E2 (PGE2), downregulated proinflammatory gene expression, and inhibited nuclear factor kappa B (NF-κB) p65, p38 mitogen-activated protein kinase, and extracellular signal-regulated kinase 1/2 (ERK 1/2) phosphorylation. These findings demonstrated the anti-inflammatory mechanisms of resveratrol-enriched rice in LPS-stimulated RAW264.7 cells. Furthermore, resveratrol-enriched rice could be a potential source of anti-inflammatory agents. Full article
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19 pages, 5032 KiB  
Article
Ultrastructural, Energy-Dispersive X-ray Spectroscopy, Chemical Study and LC-DAD-QToF Chemical Characterization of Cetraria islandica (L.) Ach
by Nurlen Manassov, Mamdouh Nabil Samy, Ubaidilla Datkhayev, Bharathi Avula, Sebastian John Adams, Kumar Katragunta, Vijayasankar Raman, Ikhlas A. Khan and Samir A. Ross
Molecules 2023, 28(11), 4493; https://doi.org/10.3390/molecules28114493 - 01 Jun 2023
Cited by 1 | Viewed by 1428
Abstract
The lichen Cetraria islandica (L.) Ach. has been used in traditional and modern medicines for its many biological properties such as immunological, immunomodulating, antioxidant, antimicrobial, and anti-inflammatory activities. This species is gaining popularity in the market, with interest from many industries for selling [...] Read more.
The lichen Cetraria islandica (L.) Ach. has been used in traditional and modern medicines for its many biological properties such as immunological, immunomodulating, antioxidant, antimicrobial, and anti-inflammatory activities. This species is gaining popularity in the market, with interest from many industries for selling as medicines, dietary supplements, and daily herbal drinks. This study profiled the morpho-anatomical features by light, fluorescence, and scanning electron microscopy; conducted an elemental analysis using energy-dispersive X-ray spectroscopy; and phytochemical analysis was performed using high-resolution mass spectrometry combined with a liquid chromatography system (LC-DAD-QToF) of C. islandica. In total, 37 compounds were identified and characterized based on comparisons with the literature data, retention times, and their mass fragmentation mechanism/s. The identified compounds were classified under five different classes, i.e., depsidones, depsides, dibenzofurans, aliphatic acids, and others that contain simple organic acids in majority. Two major compounds (fumaroprotocetraric acid and cetraric acid) were identified in the aqueous ethanolic and ethanolic extracts of C. islandica lichen. This detailed morpho-anatomical, EDS spectroscopy, and the developed LC-DAD-QToF approach for C. islandica will be important for correct species identification and can serve as a useful tool for taxonomical validation and chemical characterization. Additionally, chemical study of the extract of C. islandica led to isolation and structural elucidation of nine compounds, namely cetraric acid (1), 9′-(O-methyl)protocetraric acid (2), usnic acid (3), ergosterol peroxide (4), oleic acid (5), palmitic acid (6), stearic acid (7), sucrose (8), and arabinitol (9). Full article
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18 pages, 1975 KiB  
Article
HPTLC Analysis and Chemical Composition of Selected Melaleuca Essential Oils
by Aimé Vázquez, Nurhayat Tabanca and Paul E. Kendra
Molecules 2023, 28(9), 3925; https://doi.org/10.3390/molecules28093925 - 06 May 2023
Cited by 5 | Viewed by 2100
Abstract
Tea tree oil (TTO) is a volatile essential oil obtained by distillation, mainly from the Australian native plant Melaleuca alternifolia (Maiden & Betche) Cheel (Myrtaceae). In this study, a comparative analysis of the chemical constituents of seven tea tree oils (M. alternifolia [...] Read more.
Tea tree oil (TTO) is a volatile essential oil obtained by distillation, mainly from the Australian native plant Melaleuca alternifolia (Maiden & Betche) Cheel (Myrtaceae). In this study, a comparative analysis of the chemical constituents of seven tea tree oils (M. alternifolia) and four other Melaleuca spp. oils (M. cajuputi, (MCa), two chemotypes of M. quinquenervia, (MNe and MNi), and M. ericifolia (MRo)) was carried out using gas chromatography–mass spectrometry (GC-MS) and high-performance thin-layer chromatography (HPTLC). Among the seven TTOs, terpinen-4-ol (37.66–44.28%), γ-terpinene (16.42–20.75%), α-terpinene (3.47–12.62%), α-terpineol (3.11–4.66%), and terpinolene (2.75–4.19%) were the most abundant compounds. On the other hand, the most abundant compounds of the other Melaleuca oils varied, such as 1,8-cineole (64.63%) in MCa oil, (E)-nerolidol (48.40%) and linalool (33.30%) in MNe oil, 1,8-cineole (52.20%) in MNi oil, and linalool (38.19%) and 1,8-cineole (27.57%) in MRo oil. HPTLC fingerprinting of Melaleuca oils enabled the discrimination of TTO oils from other Melaleuca spp. oils. Variation was observed in the profile of the Rf values among EOs. The present study shows that HPTLC is one of the best ways to identify and evaluate the quality control in authenticating TTOs, other Melaleuca EOs, or EOs from other species within the Myrtaceae. Full article
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7 pages, 597 KiB  
Communication
Bioassay-Guided Fractionation with Antimalarial and Antimicrobial Activities of Paeonia officinalis
by Mamdouh Nabil Samy, Basma Khalaf Mahmoud, Nourhan Hisham Shady, Usama Ramadan Abdelmohsen and Samir Anis Ross
Molecules 2022, 27(23), 8382; https://doi.org/10.3390/molecules27238382 - 01 Dec 2022
Cited by 4 | Viewed by 1284
Abstract
Bioassay-guided fractionation technique of roots of Paeonia officinalis led to isolation and structure elucidation of seven known compounds, including four monoterpene glycosides: lactiflorin (1), paeoniflorin (4), galloyl paeoniflorin (5), and (Z)-(1S,5R)- [...] Read more.
Bioassay-guided fractionation technique of roots of Paeonia officinalis led to isolation and structure elucidation of seven known compounds, including four monoterpene glycosides: lactiflorin (1), paeoniflorin (4), galloyl paeoniflorin (5), and (Z)-(1S,5R)-β-pinen-10-yl β-vicianoside (7); two phenolics: benzoic acid (2) and methyl gallate (3); and one sterol glycoside: β-sitosterol 3-O-β-D-glucopyranoside (6). The different fractions and the isolated compounds were evaluated for their antimicrobial and antimalarial activities. Fraction II and III showed antifungal activity against Candida neoformans with IC50 values of 28.11 and 74.37 µg/mL, respectively, compared with the standard fluconazole (IC50 = 4.68 µg/mL), and antibacterial potential against Pseudomonas aeruginosa (IC50 = 20.27 and 24.82 µg/mL, respectively) and Klebsiella pneumoniae (IC50 = 43.21 and 94.4 µg/mL, respectively), compared with the standard meropenem (IC50 = 28.67 and 43.94 µg/mL, respectively). Compounds 3 and 5 showed antimalarial activity against Plasmodium falciparum D6 with IC50 values of 1.57 and 4.72 µg/mL and P. falciparum W2 with IC50 values of 0.61 and 2.91 µg/mL, respectively, compared with the standard chloroquine (IC50 = 0.026 and 0.14 µg/mL, respectively). Full article
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Review

Jump to: Research

44 pages, 3796 KiB  
Review
A Review of the Popular Uses, Anatomical, Chemical, and Biological Aspects of Kalanchoe (Crassulaceae): A Genus of Plants Known as “Miracle Leaf”
by Evelyn Assis de Andrade, Isadora Machinski, Ana Carolina Terso Ventura, Sarah Ainslie Barr, Airton Vicente Pereira, Flávio Luís Beltrame, Wendy Karen Strangman and Robert Thomas Williamson
Molecules 2023, 28(14), 5574; https://doi.org/10.3390/molecules28145574 - 21 Jul 2023
Viewed by 5812
Abstract
Species of the genus Kalanchoe have a long history of therapeutic use in ethnomedicine linked to their remarkable healing properties. Several species have chemical and anatomical similarities, often leading to confusion when they are used in folk medicine. This review aims to provide [...] Read more.
Species of the genus Kalanchoe have a long history of therapeutic use in ethnomedicine linked to their remarkable healing properties. Several species have chemical and anatomical similarities, often leading to confusion when they are used in folk medicine. This review aims to provide an overview and discussion of the reported traditional uses, botanical aspects, chemical constituents, and pharmacological potential of the Kalanchoe species. Published scientific materials were collected from the PubMed and SciFinder databases without restriction regarding the year of publication through April 2023. Ethnopharmacological knowledge suggests that these species have been used to treat infections, inflammation, injuries, and other disorders. Typically, all parts of the plant are used for medicinal purposes either as crude extract or juice. Botanical evaluation can clarify species differentiation and can enable correct identification and validation of the scientific data. Flavonoids are the most common classes of secondary metabolites identified from Kalanchoe species and can be correlated with some biological studies (antioxidant, anti-inflammatory, and antimicrobial potential). This review summarizes several topics related to the Kalanchoe genus, supporting future studies regarding other unexplored research areas. The need to conduct further studies to confirm the popular uses and biological activities of bioactive compounds is also highlighted. Full article
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46 pages, 5204 KiB  
Review
Apiaceae Medicinal Plants in China: A Review of Traditional Uses, Phytochemistry, Bolting and Flowering (BF), and BF Control Methods
by Meiling Li, Min Li, Li Wang, Mengfei Li and Jianhe Wei
Molecules 2023, 28(11), 4384; https://doi.org/10.3390/molecules28114384 - 27 May 2023
Cited by 4 | Viewed by 1716
Abstract
Apiaceae plants have been widely used in traditional Chinese medicine (TCM) for the removing dampness, relieving superficies, and dispelling cold, etc. In order to exploit potential applications as well as improve the yield and quality of Apiaceae medicinal plants (AMPs), the traditional use, [...] Read more.
Apiaceae plants have been widely used in traditional Chinese medicine (TCM) for the removing dampness, relieving superficies, and dispelling cold, etc. In order to exploit potential applications as well as improve the yield and quality of Apiaceae medicinal plants (AMPs), the traditional use, modern pharmacological use, phytochemistry, effect of bolting and flowering (BF), and approaches for controlling BF were summarized. Currently, about 228 AMPs have been recorded as TCMs, with 6 medicinal parts, 79 traditional uses, 62 modern pharmacological uses, and 5 main kinds of metabolites. Three different degrees (i.e., significantly affected, affected to some extent, and not significantly affected) could be classed based on the yield and quality. Although the BF of some plants (e.g., Angelica sinensis) could be effectively controlled by standard cultivation techniques, the mechanism of BF has not yet been systemically revealed. This review will provide useful references for the reasonable exploration and high-quality production of AMPs. Full article
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35 pages, 1354 KiB  
Review
Elderberry Extracts: Characterization of the Polyphenolic Chemical Composition, Quality Consistency, Safety, Adulteration, and Attenuation of Oxidative Stress- and Inflammation-Induced Health Disorders
by Ahmed G. Osman, Bharathi Avula, Kumar Katragunta, Zulfiqar Ali, Amar G. Chittiboyina and Ikhlas A. Khan
Molecules 2023, 28(7), 3148; https://doi.org/10.3390/molecules28073148 - 31 Mar 2023
Cited by 9 | Viewed by 3211
Abstract
Elderberry is highly reputed for its health-improving effects. Multiple pieces of evidence indicate that the consumption of berries is linked to enhancing human health and preventing or delaying the onset of chronic medical conditions. Compared with other fruit, elderberry is a very rich [...] Read more.
Elderberry is highly reputed for its health-improving effects. Multiple pieces of evidence indicate that the consumption of berries is linked to enhancing human health and preventing or delaying the onset of chronic medical conditions. Compared with other fruit, elderberry is a very rich source of anthocyanins (approximately 80% of the polyphenol content). These polyphenols are the principals that essentially contribute to the high antioxidant and anti-inflammatory capacities and the health benefits of elderberry fruit extract. These health effects include attenuation of cardiovascular, neurodegenerative, and inflammatory disorders, as well as anti-diabetic, anticancer, antiviral, and immuno-stimulatory effects. Sales of elderberry supplements skyrocketed to $320 million over the year 2020, according to an American Botanical Council (ABC) report, which is attributable to the purported immune-enhancing effects of elderberry. In the current review, the chemical composition of the polyphenolic content of the European elderberry (Sambucus nigra) and the American elderberry (Sambucus canadensis), as well as the analytical techniques employed to analyze, characterize, and ascertain the chemical consistency will be addressed. Further, the factors that influence the consistency of the polyphenolic chemical composition, and hence, the consistency of the health benefits of elderberry extracts will be presented. Additionally, adulteration and safety as factors contributing to consistency will be covered. The role of elderberry in enhancing human health alone with the pharmacological basis, the cellular pathways, and the molecular mechanisms underlying the observed health benefits of elderberry fruit extracts will be also reviewed. Full article
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