Editorial

5 pages, 213 KiB

Open AccessEditorial

Bioavailability and Bioactivity of Plant Antioxidants

by Dorota Żyżelewicz and Joanna Oracz

Antioxidants 2022, 11(12), 2336; https://doi.org/10.3390/antiox11122336 - 25 Nov 2022

Cited by 8 | Viewed by 1602

Plant-derived antioxidants are a large group of chemical compounds that include the secondary metabolites of plants (e [...] Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

Research

Jump to: Editorial, Review

20 pages, 974 KiB

Open AccessArticle

Simulated Gastrointestinal Digestion of Bioprocessed Spelt Seeds: Bioaccessibility and Bioactivity of Phenolics

by Marjeta Mencin, Maja Mikulič Petkovšek, Robert Veberič and Petra Terpinc

Antioxidants 2022, 11(9), 1703; https://doi.org/10.3390/antiox11091703 - 30 Aug 2022

Cited by 5 | Viewed by 1473

Abstract

The goal of this research was to evaluate the impact of different bioprocessing techniques on improved bioaccessibility of phenolics from spelt seeds. Despite the negative influence of gastrointestinal digestion, fermentation of germinated seeds significantly increased the bioaccessibility of total phenolics and their antioxidant [...] Read more.

The goal of this research was to evaluate the impact of different bioprocessing techniques on improved bioaccessibility of phenolics from spelt seeds. Despite the negative influence of gastrointestinal digestion, fermentation of germinated seeds significantly increased the bioaccessibility of total phenolics and their antioxidant activity compared to digested raw seeds. Enzymatic treated fermented seeds showed the highest relative bioaccessibility of p-coumaric and trans-ferulic acids, while their absolute contents were significantly higher in “germinated + fermented” seeds. Our research suggests that pretreatment of spelt seeds with hydrolytic enzymes improves access of fermenting microorganisms to structural elements, resulting in an increased content of extractable and bound trans-ferulic acid. Significantly higher biostability of phenolics was observed in raw seeds. Some major quality changes in the composition of extracts were observed under simulated in vitro digestion, since antioxidants of the same extract showed a different relative decrease in DPPH^• and ABTS^•+ scavenging activities compared to the raw seeds or their corresponding undigested counterparts. It is therefore important to increase the content of extractable antioxidants in seeds by bioprocessing, since they are strongly diminished during digestion. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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15 pages, 1773 KiB

Open AccessArticle

Metabolic Analyses and Evaluation of Antioxidant Activity in Purple Kohlrabi Sprouts after Exposed to UVB Radiation

by Hyeon Ji Yeo, Soo-Yeon Lim, Chang Ha Park, Cha Young Kim, Ramaraj Sathasivam, Jae Kwang Kim and Sang Un Park

Antioxidants 2022, 11(8), 1443; https://doi.org/10.3390/antiox11081443 - 25 Jul 2022

Cited by 4 | Viewed by 1509

Abstract

Various metabolites act as plant defense molecules due to their antioxidant abilities. This study aimed to investigate the influence of UVB irradiation on the accumulation of metabolites, including primary metabolites (sugar, sugar alcohols, amino acids, organic acids, and an amine) and secondary metabolites [...] Read more.

Various metabolites act as plant defense molecules due to their antioxidant abilities. This study aimed to investigate the influence of UVB irradiation on the accumulation of metabolites, including primary metabolites (sugar, sugar alcohols, amino acids, organic acids, and an amine) and secondary metabolites (anthocyanins, fatty acids, and phenolic acids), and its synergistic antioxidant ability, in purple kohlrabi sprouts. Metabolite analyses revealed a total of 92 metabolites in the sprouts. Specifically, the levels of most amino acids increased after 24 h of UVB treatment, and then slightly decreased in the kohlrabi sprouts. The levels of most sugars and sugar alcohols increased after 24 h of UVB treatment and then decreased. The levels of TCA cycle intermediates and phenolic acids gradually increased during the UVB treatment. Furthermore, the levels of some fatty acids gradually increased during the UVB treatment, and the levels of the other fatty acids increased after 6 h of UVB treatment and then decreased. In particular, the levels of most anthocyanins, known to be strong antioxidants, gradually increased after 24 h of UVB treatment. In the in vitro ABTS scavenging assay, UVB-treated purple kohlrabi sprouts showed increased scavenging ability. This may be attributed to the increased accumulation of metabolites acting as antioxidants, in response to UVB treatment. This study confirmed that UVB irradiation induced the alteration of primary and secondary metabolism in the kohlrabi sprouts. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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16 pages, 4788 KiB

Open AccessArticle

Glycosylation of Epigallocatechin Gallate by Engineered Glycoside Hydrolases from Talaromyces amestolkiae: Potential Antiproliferative and Neuroprotective Effect of These Molecules

by Juan A. Méndez-Líter, Ana Pozo-Rodríguez, Enrique Madruga, María Rubert, Andrés G. Santana, Laura I. de Eugenio, Cristina Sánchez, Ana Martínez, Alicia Prieto and María Jesús Martínez

Antioxidants 2022, 11(7), 1325; https://doi.org/10.3390/antiox11071325 - 05 Jul 2022

Cited by 5 | Viewed by 1712

Abstract

Glycoside hydrolases (GHs) are enzymes that hydrolyze glycosidic bonds, but some of them can also catalyze the synthesis of glycosides by transglycosylation. However, the yields of this reaction are generally low since the glycosides formed end up being hydrolyzed by these same enzymes. [...] Read more.

Glycoside hydrolases (GHs) are enzymes that hydrolyze glycosidic bonds, but some of them can also catalyze the synthesis of glycosides by transglycosylation. However, the yields of this reaction are generally low since the glycosides formed end up being hydrolyzed by these same enzymes. For this reason, mutagenic variants with null or drastically reduced hydrolytic activity have been developed, thus enhancing their synthetic ability. Two mutagenic variants, a glycosynthase engineered from a β-glucosidase (BGL-1-E521G) and a thioglycoligase from a β-xylosidase (BxTW1-E495A), both from the ascomycete Talaromyces amestolkiae, were used to synthesize three novel epigallocatechin gallate (EGCG) glycosides. EGCG is a phenolic compound from green tea known for its antioxidant effects and therapeutic benefits, whose glycosylation could increase its bioavailability and improve its bioactive properties. The glycosynthase BGL-1-E521G produced a β-glucoside and a β-sophoroside of EGCG, while the thioglycoligase BxTW1-E495A formed the β-xyloside of EGCG. Glycosylation occurred in the 5″ and 4″ positions of EGCG, respectively. In this work, the reaction conditions for glycosides’ production were optimized, achieving around 90% conversion of EGCG with BGL-1-E521G and 60% with BxTW1-E495A. The glycosylation of EGCG caused a slight loss of its antioxidant capacity but notably increased its solubility (between 23 and 44 times) and, in the case of glucoside, also improved its thermal stability. All three glycosides showed better antiproliferative properties on breast adenocarcinoma cell line MDA-MB-231 than EGCG, and the glucosylated and sophorylated derivatives induced higher neuroprotection, increasing the viability of SH-S5Y5 neurons exposed to okadaic acid. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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20 pages, 3923 KiB

Open AccessArticle

Transcriptomic and Widely Targeted Metabolomic Approach Identified Diverse Group of Bioactive Compounds, Antiradical Activities, and Their Associated Genes in Six Sugarcane Varieties

by Muhammad Junaid Rao, Mingzheng Duan, Jihong Wang, Shijian Han, Li Ma, Xinyi Mo, Min Li, Lihua Hu and Lingqiang Wang

Antioxidants 2022, 11(7), 1319; https://doi.org/10.3390/antiox11071319 - 04 Jul 2022

Cited by 7 | Viewed by 1612

Abstract

Sugarcane is cultivated mainly for its high sucrose content but it can also produce many metabolites with promising antioxidant potential. However, very few studies have been reported on the biosynthesis of metabolites in sugarcane to date. In this study, we have identified a [...] Read more.

Sugarcane is cultivated mainly for its high sucrose content but it can also produce many metabolites with promising antioxidant potential. However, very few studies have been reported on the biosynthesis of metabolites in sugarcane to date. In this study, we have identified a wide range of amino acids and organic acids in the rind of six sugarcane varieties by the LC-MS/MS method. A total number of 72 amino acids and 55 organic acid compounds were characterized; among these, 100 were reported for the first time. Moreover, 13 amino acids and seven organic acids were abundantly distributed in all varieties tested and considered major amino acids and organic acids in sugarcane. The variety Taitang134 (F134) showed the highest content of total amino acids, whereas the varieties ROC16 and Yuetang93/159 (YT93/159) had maximum content of organic acids. The amino acids of the rind extract presented higher antioxidant capacity than the organic acids of the rind extract. In addition, the transcriptomic and metabolic integrated analysis highlighted some candidate genes associated with amino acid biosynthesis in sugarcane. We selected a transcription factor gene, MYB(t), and over-expressed it in Arabidopsis. The transgenic plants showed a higher accumulation of amino acids with higher antiradical activity compared with the wild-type Arabidopsis plants. Thus, we characterize a wide range of amino acids and organic acids and their antiradical activities in different sugarcane varieties and present candidate genes that can be potentially valuable for the genetic improvement of metabolites in sugarcane bagasse Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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14 pages, 2054 KiB

Open AccessArticle

Antioxidant and DNA-Protective Potentials, Main Phenolic Compounds, and Microscopic Features of Koelreuteria paniculata Aerial Parts

by Tsvetelina Andonova, Yordan Muhovski, Radka Vrancheva, Ilya Slavov, Elena Apostolova, Samir Naimov, Atanas Pavlov and Ivanka Dimitrova-Dyulgerova

Antioxidants 2022, 11(6), 1154; https://doi.org/10.3390/antiox11061154 - 13 Jun 2022

Cited by 5 | Viewed by 1733

Abstract

Interest in plant extracts as a natural source of antioxidants has grown significantly in recent years. The tree species Koelreuteria paniculata deserves attention due to its wide distribution, good adaptability, and growth to the degree of invasiveness in a number of European countries. [...] Read more.

Interest in plant extracts as a natural source of antioxidants has grown significantly in recent years. The tree species Koelreuteria paniculata deserves attention due to its wide distribution, good adaptability, and growth to the degree of invasiveness in a number of European countries. The purpose of the present study was to analyze flavonoids and phenolic acids of the ethanol extracts from aerial parts of K. paniculata and to screen their antioxidant and DNA-protective activity. HPLC profiling revealed the presence of five flavonoids, with rutin (4.23 mg/g DW), hesperidin (2.97 mg/g DW), and quercetin (2.66 mg/g DW) as the major ones in the leaves, and (−)-epicatechin (2.69 mg/g DW) in the flower buds. Among the nine phenolic acids identified, rosmarinic, p-coumaric, salicylic, vanillic, and gallic acids were the best represented. All the extracts tested showed in vitro antioxidant activity that was determined by DPPH, ABTS, FRAP, and CUPRAC assays. The highest activity was recorded in the flower parts (in the range from 1133 to 4308 mmol TE/g DW). The DNA-protective capacity of the flower and stem bark extracts from the in vitro nicking assay performed, as well as the main diagnostic microscopic features of the plant substances, are given for the first time. According to the results obtained, the aerial parts of K. paniculata could be valuable sources of natural antioxidants. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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14 pages, 2026 KiB

Open AccessArticle

Effects of Grape Pomace Polyphenols and In Vitro Gastrointestinal Digestion on Antimicrobial Activity: Recovery of Bioactive Compounds

by Giusy Rita Caponio, Mirella Noviello, Francesco Maria Calabrese, Giuseppe Gambacorta, Gianluigi Giannelli and Maria De Angelis

Antioxidants 2022, 11(3), 567; https://doi.org/10.3390/antiox11030567 - 16 Mar 2022

Cited by 30 | Viewed by 3625

Abstract

Grape pomace (GP), a major byproduct obtained from the winemaking process, is characterized by a high amount of phenolic compounds and secondary plant metabolites, with potential beneficial effects on human health. Therefore, GP is a source of bioactive compounds with antioxidant, antimicrobial, and [...] Read more.

Grape pomace (GP), a major byproduct obtained from the winemaking process, is characterized by a high amount of phenolic compounds and secondary plant metabolites, with potential beneficial effects on human health. Therefore, GP is a source of bioactive compounds with antioxidant, antimicrobial, and anti-inflammatory activity. As people are paying more attention to sustainability, in this work, we evaluate two different extractions (aqueous and hydroalcoholic) of GP bioactive compounds. In vitro simulated gastrointestinal digestion of the GP extracts was performed to improve the bioavailability and bioaccessibility of polyphenols. The antioxidant activity (ABTS and DPPH assays) and the phenolic characterization of the extracts by UHPLC-DAD were evaluated. The antimicrobial effects of GP antioxidants in combination with a probiotic (Lactiplantibacillus plantarum) on the growth of pathogenic microorganisms (Escherichia coli, Bacillus megaterium, and Listeria monocytogenes) were evaluated. As a result, an increase of antioxidant activity of aqueous GP extracts during the gastrointestinal digestion, and a contextual decrease of hydroalcoholic extracts, were detected. The main compounds assessed by UHPLC-DAD were anthocyanins, phenolic acids, flavonoids, and stilbenes. Despite lower antioxidant activity, due to the presence of antimicrobial active compounds, the aqueous extracts inhibited the growth of pathogens. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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18 pages, 2717 KiB

Open AccessArticle

Thermal Stability and Inhibitory Action of Red Grape Skin Phytochemicals against Enzymes Associated with Metabolic Syndrome

by Daniela Serea, Nina Nicoleta Condurache, Iuliana Aprodu, Oana Emilia Constantin, Gabriela-Elena Bahrim, Nicoleta Stănciuc, Silvius Stanciu and Gabriela Rapeanu

Antioxidants 2022, 11(1), 118; https://doi.org/10.3390/antiox11010118 - 05 Jan 2022

Cited by 9 | Viewed by 2156

Abstract

The present study focuses on heat-induced structural changes and the degradation kinetics of phytochemicals and antioxidant activity of red grape skin extract. The thermal degradation of anthocyanins, flavonoids, polyphenols, and antioxidant activity followed a first-order kinetic model, increasing with temperature due to the [...] Read more.

The present study focuses on heat-induced structural changes and the degradation kinetics of phytochemicals and antioxidant activity of red grape skin extract. The thermal degradation of anthocyanins, flavonoids, polyphenols, and antioxidant activity followed a first-order kinetic model, increasing with temperature due to the intensification of the degradation process. The activation energy (Ea) highlighted this phenomenon. Likewise, the kinetic and thermodynamic parameters certified the irreversible degradation of the bioactive compounds from the skin of the Băbească neagră grape variety. Both temperature and duration of heating had a significant impact on the content of bioactive compounds. In addition, the red grape skin extract inhibited certain enzymes such as α-amylase, α-glucosidase, lipase, and lipoxygenase, which are associated with metabolic syndrome and inflammation. Further knowledge on the possible inhibition mechanisms exerted by the major anthocyanins found in red grape skin extract on the metabolic syndrome-associated enzymes was gathered upon running molecular docking tests. Detailed analysis of the resulting molecular models revealed that malvidin 3-O-glucoside binds in the vicinity of the catalytic site of α-amylase and lipase, whereas no direct contact with catalytic amino acids was identified in the case of α-glucosidase and lipoxygenase. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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14 pages, 1467 KiB

Open AccessArticle

Linking the Dynamic Changes in the In Vitro Antioxidant Activity of Carob Kibbles upon Roasting to the Chemical and Structural Changes Revealed by FTIR Spectroscopy

by Anna Marina Grigoriou and Eftychia Pinakoulaki

Antioxidants 2021, 10(12), 2025; https://doi.org/10.3390/antiox10122025 - 20 Dec 2021

Cited by 5 | Viewed by 2539

Abstract

Recent studies have highlighted the potential of utilizing carob kibbles as a bioactive-rich food ingredient associated with substantial health benefits. Roasting is a key process in enhancing the sensory characteristics of carob kibbles, also affecting the bioactive polyphenols and leading to the formation [...] Read more.

Recent studies have highlighted the potential of utilizing carob kibbles as a bioactive-rich food ingredient associated with substantial health benefits. Roasting is a key process in enhancing the sensory characteristics of carob kibbles, also affecting the bioactive polyphenols and leading to the formation of Maillard reaction products (MRPs), including the polymeric melanoidins that are associated with a high antioxidant potential but remain unexplored in carob. In this work, we employed for the first time attenuated total reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy to probe the dynamic chemical and structural changes upon the roasting of carob kibbles, along with the investigation of the in vitro antioxidant activity through the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and the determination of the total polyphenolic, proanthocyanidin, gallic acid and cinnamic acid contents. Roasting significantly enhanced the in vitro antioxidant activity of the polyphenolic carob extracts, with different rates at distinct roasting temperatures. The ATR-FTIR analysis enabled the identification of the changes in the structural features of polyphenolic compounds that were related to the improved antioxidant activity upon roasting. Furthermore, the detection of characteristic signatures for the polymeric melanoidins in the infrared (IR) fingerprint region provided the first evidence for the formation and structural properties of these complex, diverse compounds in roasted carob kibbles. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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17 pages, 415 KiB

Open AccessArticle

Comparison of the Content of Selected Bioactive Components and Antiradical Properties in Yoghurts Enriched with Chia Seeds (Salvia hispanica L.) and Chia Seeds Soaked in Apple Juice

by Beata Drużyńska, Rafał Wołosiak, Monika Grzebalska, Ewa Majewska, Marta Ciecierska and Elwira Worobiej

Antioxidants 2021, 10(12), 1989; https://doi.org/10.3390/antiox10121989 - 14 Dec 2021

Cited by 7 | Viewed by 2330

Abstract

Due to the fact that consumers are looking for new, health-promoting products, there is a growing interest in various ingredients with a high biological activity that could enrich conventional foods. As is known, chia seeds are a rich source of various health-promoting compounds. [...] Read more.

Due to the fact that consumers are looking for new, health-promoting products, there is a growing interest in various ingredients with a high biological activity that could enrich conventional foods. As is known, chia seeds are a rich source of various health-promoting compounds. The objective of this study was to determine the content of selected biologically active compounds and their antioxidant properties by means of DPPH^●, ABTS^+●, and the ability to chelate Fe (II) ions in chia seeds and yoghurts with the addition of these seeds and seeds soaked in apple juice. It was found that chia seeds are a rich source of bioactive ingredients with beneficial effects on human health—especially polyphenols. All the extracts showed antioxidant properties against the radicals used. The addition of seeds to yoghurt contributed to the presence of polyphenols, while soaking in apple juice resulted in a higher content of polyphenols in yoghurts. The enriched yoghurt extracts showed antioxidant properties against DPPH radicals and the ability to chelate Fe (II) ions. The addition of seeds soaked in apple juice significantly influenced the antioxidant activity against ABTS radicals. The addition of seeds (plain and soaked) did not cause significant changes in the pH of the yoghurts. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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10 pages, 1146 KiB

Open AccessArticle

Impact of Simulated Gastrointestinal Conditions on Antiglycoxidant and α-Glucosidase Inhibition Capacities of Cyanidin-3-O-Glucoside

by Didier Fraisse, Alexis Bred, Catherine Felgines and François Senejoux

Antioxidants 2021, 10(11), 1670; https://doi.org/10.3390/antiox10111670 - 23 Oct 2021

Cited by 3 | Viewed by 1649

Abstract

Cyanidin-3-O-glucoside (C3G) is a widespread anthocyanin derivative, which has been reported in vitro to exert potent antioxidant, antiglycation and α-glucosidase inhibition effects. Nevertheless, the physiological relevance of such properties remains uncertain considering its significant instability in gastrointestinal conditions. A simulated digestion [...] Read more.

Cyanidin-3-O-glucoside (C3G) is a widespread anthocyanin derivative, which has been reported in vitro to exert potent antioxidant, antiglycation and α-glucosidase inhibition effects. Nevertheless, the physiological relevance of such properties remains uncertain considering its significant instability in gastrointestinal conditions. A simulated digestion procedure was thus instigated to assess the influence of gastric and intestinal media on its chemical integrity and biological activities. HPLC analyses of digested C3G samples confirmed the striking impact of intestinal conditions, as attested by a decomposition ratio of 70%. In contrast, with recovery rates of around 90%, antiglycation, as well as DPPH and ABTS scavenging assays, uniformly revealed a noteworthy persistence of its antiglycoxidant capacities. Remarkably, a prominent increase of its α-glucosidase inhibition activity was even observed after the intestinal phase, suggesting that classical in vitro evaluations might underestimate C3G antidiabetic potential. Consequently, the present data provide novel and specific insights on C3G’s digestive fate, suggesting that the gastrointestinal tract does not profoundly affect its positive action on oxidative and carbonyl stresses. More specifically, it also tends to support its regulating effects on postprandial hyperglycemia and its potential usefulness for diabetes management. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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12 pages, 299 KiB

Open AccessArticle

LC-ESI-LTQ-Orbitrap-MS for Profiling the Distribution of Oleacein and Its Metabolites in Rat Tissues

by Anallely López-Yerena, Anna Vallverdú-Queralt, Rosa M. Lamuela-Raventós and Elvira Escribano-Ferrer

Antioxidants 2021, 10(7), 1083; https://doi.org/10.3390/antiox10071083 - 05 Jul 2021

Cited by 5 | Viewed by 1986

Abstract

The purpose of this work was to study the distribution of oleacein (OLEA) and its metabolites in rat plasma and different tissues, namely brain, heart, kidney, liver, lung, small intestine, spleen, stomach, skin, and thyroid, following the acute intake of a refined olive [...] Read more.

The purpose of this work was to study the distribution of oleacein (OLEA) and its metabolites in rat plasma and different tissues, namely brain, heart, kidney, liver, lung, small intestine, spleen, stomach, skin, and thyroid, following the acute intake of a refined olive oil containing 0.3 mg/mL of OLEA. For this purpose, a distribution kinetics study was carried out. The plasma and tissues were collected at 1, 2, and 4.5 h after the intervention, and analyzed by LC-ESI-LTQ-Orbitrap-MS. Unmetabolized OLEA was detected in the stomach, small intestine, liver, plasma and, most notably, the heart. This finding may be useful for the development of new applications of OLEA for cardiovascular disease prevention. Noteworthy are also the high levels of hydroxytyrosol (OH-TY) and OLEA + CH₃ found in the small intestine, liver, and plasma, and the detection of nine OLEA metabolites, five of them arising from conjugation reactions. Liver, heart, spleen, and lungs were the target tissues where the metabolites were most distributed. However, it is important to note that OH-TY, in our experimental conditions, was not detected in any target tissue (heart, spleen, thyroids, lungs, brain, and skin). These results shed further light on the metabolism and tissue distribution of OLEA and contribute to understanding the mechanisms underlying its effect in human health. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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23 pages, 14857 KiB

Open AccessArticle

Impact of Protein-Enriched Plant Food Items on the Bioaccessibility and Cellular Uptake of Carotenoids

by Mohammed Iddir, Juan Felipe Porras Yaruro, Emmanuelle Cocco, Emilie M. Hardy, Brice M. R. Appenzeller, Cédric Guignard, Yvan Larondelle and Torsten Bohn

Antioxidants 2021, 10(7), 1005; https://doi.org/10.3390/antiox10071005 - 23 Jun 2021

Cited by 17 | Viewed by 2840

Abstract

Carotenoids are lipophilic pigments which have been associated with a number of health benefits, partly related to antioxidant effects. However, due to their poor solubility during digestion, carotenoid bioavailability is low and variable. In this study, we investigated the effect of frequently consumed [...] Read more.

Carotenoids are lipophilic pigments which have been associated with a number of health benefits, partly related to antioxidant effects. However, due to their poor solubility during digestion, carotenoid bioavailability is low and variable. In this study, we investigated the effect of frequently consumed proteins on carotenoid bioaccessibility and cellular uptake. Whey protein isolate (WPI), soy protein isolate (SPI), sodium caseinate (SC), gelatin (GEL), turkey and cod, equivalent to 0/10/25/50% of the recommended dietary allowance (RDA, approx. 60g/d), were co-digested gastro-intestinally with carotenoid-rich food matrices (tomato and carrot juice, spinach), and digesta further studied in Caco-2 cell models. Lipid digestion, surface tension and microscopic visualization were also carried out. Co-digested proteins positively influenced the micellization of carotenes (up to 3-fold, depending on type and concentration), especially in the presence of SPI (p < 0.001). An increased cellular uptake was observed for xanthophylls/carotenes (up to 12/33%, p < 0.001), which was stronger for matrices with an initially poor carotenoid micellization (i.e., tomato juice, p < 0.001), similar to what was encountered for bioaccessibility. Turkey and cod had a weaker impact. Significant interactions between carotenoids, lipids and proteins were observed during digestion. Co-digested proteins generally improved lipid digestion in all matrices (p < 0.001), especially for carrot juice, though slight decreases were observed for GEL. Protein impact on the surface tension was limited. In conclusion, proteins generally improved both carotenoid bioaccessibility and cellular uptake, depending on the matrices and carotenoid-type (i.e., carotene vs. xanthophylls), which may be relevant under specific circumstances, such as intake of carotenoid-rich food items low in lipids. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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15 pages, 583 KiB

Open AccessArticle

Apple Pomace as a Source of Bioactive Polyphenol Compounds in Gluten-Free Breads

by Dorota Gumul, Rafał Ziobro, Jarosław Korus and Marek Kruczek

Antioxidants 2021, 10(5), 807; https://doi.org/10.3390/antiox10050807 - 19 May 2021

Cited by 25 | Viewed by 3503

Abstract

Gluten-free products based on starch and hydrocolloids are deficient in nutrients and do not contain pro-health substances. Therefore, they should be enriched in raw materials naturally rich in antioxidants, especially if they are intended for celiac patients, prone to high oxidative stress. Apart [...] Read more.

Gluten-free products based on starch and hydrocolloids are deficient in nutrients and do not contain pro-health substances. Therefore, they should be enriched in raw materials naturally rich in antioxidants, especially if they are intended for celiac patients, prone to high oxidative stress. Apart from the traditionally used pseudo-cereals, seeds, vegetables and fruits, innovative substrates such as the by-product (especially in Poland) dry apple pomace could be applied. The study material consisted of gluten-free bread enriched with apple pomace. The content of individual polyphenols, the content of total polyphenol and flavonoids, and also the antioxidant potential of the bread were determined by the UPLC-PDA-MS/MS methods. It was observed that apple pomace was a natural concentrate of bioactive substances from the group of polyphenols. In summary, gluten-free bread with 5% content of apple pomace showed the highest organoleptic scores and contained high levels of phenolic compounds. The values of total phenolic content, and the amounts of flavonoids, phenolic acids and phloridzin in this bread were 2.5, 8, 4 and 21 times higher in comparison to control. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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14 pages, 2823 KiB

Open AccessArticle

Tissue Distribution of Oleocanthal and Its Metabolites after Oral Ingestion in Rats

by Anallely López-Yerena, Anna Vallverdú-Queralt, Olga Jáuregui, Xavier Garcia-Sala, Rosa M. Lamuela-Raventós and Elvira Escribano-Ferrer

Antioxidants 2021, 10(5), 688; https://doi.org/10.3390/antiox10050688 - 27 Apr 2021

Cited by 16 | Viewed by 2780

Abstract

Claims for the potential health benefits of oleocanthal (OLC), a dietary phenolic compound found in olive oil, are based mainly on in vitro studies. Little is known about the tissue availability of OLC, which is rapidly metabolized after ingestion. In this study, the [...] Read more.

Claims for the potential health benefits of oleocanthal (OLC), a dietary phenolic compound found in olive oil, are based mainly on in vitro studies. Little is known about the tissue availability of OLC, which is rapidly metabolized after ingestion. In this study, the distribution of OLC and its metabolites in rat plasma and tissues (stomach, intestine, liver, kidney, spleen, lungs, heart, brain, thyroid and skin) at 1, 2 and 4.5 h after the acute intake of a refined olive oil containing 0.3 mg/mL of OLC was examined by LC-ESI-LTQ-Orbitrap-MS. OLC was only detected in the stomach and intestine samples. Moreover, at 2 and 4.5 h, the concentration in the stomach decreased by 36% and 74%, respectively, and in the intestine by 16% and 33%, respectively. Ten OLC metabolites arising from phase I and phase II reactions were identified. The metabolites were widely distributed in rat tissues, and the most important metabolizing organs were the small intestine and liver. The two main circulating metabolites were the conjugates OLC + OH + CH₃ and OLC + H₂O + glucuronic acid, which may significantly contribute to the beneficial health effects associated with the regular consumption of extra virgin olive oil. However, more studies are necessary to determine the concentrations and molecular structures of OLC metabolites in human plasma and tissues when consumed with the presence of other phenolic compunds present in EVOO. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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12 pages, 9415 KiB

Open AccessArticle

Kinetics Drying of Blackberry Bagasse and Degradation of Anthocyanins and Bioactive Properties

by Dorila E. Grández-Yoplac, Diner Mori-Mestanza, Lucas D. Muñóz-Astecker, Ilse S. Cayo-Colca and Efraín M. Castro-Alayo

Antioxidants 2021, 10(4), 548; https://doi.org/10.3390/antiox10040548 - 01 Apr 2021

Cited by 5 | Viewed by 2377

Abstract

The process of drying food is necessary to preserve it; however, some bioactive compounds can be degraded during drying process. In this work, the convective drying process of Peruvian blackberry bagasse and the degradation of anthocyanins, total phenolic content (TPC), and antioxidant capacity [...] Read more.

The process of drying food is necessary to preserve it; however, some bioactive compounds can be degraded during drying process. In this work, the convective drying process of Peruvian blackberry bagasse and the degradation of anthocyanins, total phenolic content (TPC), and antioxidant capacity (AC) were studied. The logarithmic model fitted well to the data and could predict the process, showing that 6 h of drying at 90 °C is enough to reach equilibrium moisture. Anthocyanin degradation followed a first-order kinetic model with reaction rate constant between 5.45 × 10⁻² ± 4.68 × 10⁻³ and 1.21 × 10⁻¹ ± 2.31 × 10⁻² h⁻¹, and activation energy of 25.11 kJ/mol. The highest retention (84.38%) of anthocyanins was obtained in 1 h at 50 °C and the highest degradation (68.54%) in 6 h at 90 °C. The TPC and AC increased with the drying time and temperature due to the increased water evaporation. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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18 pages, 2824 KiB

Open AccessArticle

New Insights into the Metabolism of the Flavanones Eriocitrin and Hesperidin: A Comparative Human Pharmacokinetic Study

by María Ángeles Ávila-Gálvez, Juan Antonio Giménez-Bastida, Antonio González-Sarrías and Juan Carlos Espín

Antioxidants 2021, 10(3), 435; https://doi.org/10.3390/antiox10030435 - 11 Mar 2021

Cited by 39 | Viewed by 5254

Abstract

The intake of hesperidin-rich sources, mostly found in orange juice, can decrease cardiometabolic risk, potentially linked to the gut microbial phase-II hesperetin derivatives. However, the low hesperidin solubility hampers its bioavailability and microbial metabolism, yielding a high inter-individual variability (high vs. low-producers) that [...] Read more.

The intake of hesperidin-rich sources, mostly found in orange juice, can decrease cardiometabolic risk, potentially linked to the gut microbial phase-II hesperetin derivatives. However, the low hesperidin solubility hampers its bioavailability and microbial metabolism, yielding a high inter-individual variability (high vs. low-producers) that prevents consistent health-related evidence. Contrarily, the human metabolism of (lemon) eriocitrin is hardly known. We hypothesize that the higher solubility of (lemon) eriocitrin vs. (orange) hesperidin might yield more bioavailable metabolites than hesperidin. A randomized-crossover human pharmacokinetic study (n = 16) compared the bioavailability and metabolism of flavanones from lemon and orange extracts and postprandial changes in oxidative, inflammatory, and metabolic markers after a high-fat-high-sugars meal. A total of 17 phase-II flavanone-derived metabolites were identified. No significant biomarker changes were observed. Plasma and urinary concentrations of all metabolites, including hesperetin metabolites, were higher after lemon extract intake. Total plasma metabolites showed significantly mean lower T_max (6.0 ± 0.4 vs. 8.0 ± 0.5 h) and higher C_max and AUC values after lemon extract intake. We provide new insights on hesperetin-eriodictyol interconversion and naringenin formation from hesperidin in humans. Our results suggest that regular consumption of a soluble and eco-friendly eriocitrin-rich lemon extract could provide a circulating concentration metabolites threshold to exert health benefits, even in the so-called low-producers. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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Review

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16 pages, 1379 KiB

Open AccessReview

Antioxidants in Hops: Bioavailability, Health Effects and Perspectives for New Products

by Corina-Aurelia Zugravu, Roxana-Elena Bohiltea, Teodor Salmen, Elena Pogurschi and Marina Ruxandra Otelea

Antioxidants 2022, 11(2), 241; https://doi.org/10.3390/antiox11020241 - 27 Jan 2022

Cited by 14 | Viewed by 5028

Abstract

Hop plant (Humulus lupulus L.) has been used by humans for ages, presumably first as a herbal remedy, then in the manufacturing of different products, from which beer is the most largely consumed. Female hops cones have different useful chemical compounds, an [...] Read more.

Hop plant (Humulus lupulus L.) has been used by humans for ages, presumably first as a herbal remedy, then in the manufacturing of different products, from which beer is the most largely consumed. Female hops cones have different useful chemical compounds, an important class being antioxidants, mainly polyphenols. This narrative review describes the main antioxidants in hops, their bioavailability and biological effects, and the results obtained by now in the primary and secondary prevention of several non-communicable diseases, such as the metabolic syndrome related diseases and oncology. This article presents in vitro and in vivo data in order to better understand what was accomplished in terms of knowledge and practice, and what needs to be clarified by additional studies, mainly regarding xantohumol and its derivates, as well as regarding the bitter acids of hops. The multiple protective effects found by different studies are hindered up to now by the low bioavailability of some of the main antioxidants in hops. However, there are new promising products with important health effects and perspectives of use as food supplements, in a market where consumers increasingly search for products originating directly from plants. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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17 pages, 1299 KiB

Open AccessReview

Wide Spectrum of Active Compounds in Sea Buckthorn (Hippophae rhamnoides) for Disease Prevention and Food Production

by Agnieszka Jaśniewska and Anna Diowksz

Antioxidants 2021, 10(8), 1279; https://doi.org/10.3390/antiox10081279 - 12 Aug 2021

Cited by 28 | Viewed by 9932

Abstract

Growing demand for value-added products and functional foods is encouraging manufacturers to consider new additives that can enrich their products and help combat lifestyle diseases. The healthy properties of sea buckthorn have been recognized for centuries. This plant has a high content of [...] Read more.

Growing demand for value-added products and functional foods is encouraging manufacturers to consider new additives that can enrich their products and help combat lifestyle diseases. The healthy properties of sea buckthorn have been recognized for centuries. This plant has a high content of bioactive compounds, including antioxidants, phytosterols, essential fatty acids, and amino acids, as well as vitamins C, K, and E. It also has a low content of sugar and a wide spectrum of volatiles, which contribute to its unique aroma. Sea buckthorn shows antimicrobial and antiviral properties, and is a potential nutraceutical or cosmeceutical. It was proven to help treat cardiovascular disease, tumors, and diabetes, as well as gastrointestinal and skin problems. The numerous health benefits of sea buckthorn make it a good candidate for incorporation into novel food products. Full article

(This article belongs to the Special Issue Bioavailability and Bioactivity of Plant Antioxidants)

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