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This paper explores the emerging subject of extracting tannins from various plant sources using deep eutectic solvents (DESs). Tannins are widely used in the food and feed industries as they have outstanding antioxidant qualities and greatly enhance the flavor and nutritional content of a wide range of food products. Organic solvents are frequently used in traditional extraction techniques, which raises questions about their safety for human health and the environment. DESs present a prospective substitute because of their low toxicity, adaptability, and environmental friendliness. The fundamental ideas supporting the application of DESs in the extraction of tannins from a range of plant-based materials frequently used in daily life are all well covered in this paper. Furthermore, this paper covers the impact of extraction parameters on the yield of extracted tannins, as well as possible obstacles and directions for future research in this emerging subject. This includes challenges such as high viscosity, intricated recovery of compounds, thermal degradation, and the occurrence of esterification. An extensive summary of the diversity, structure, biosynthesis, distribution, and roles of tannins in plants is given in this paper. Additionally, this paper thoroughly examines various bioactivities of tannins and their metabolites. [ABSTRACT FROM AUTHOR]

In our search for bioactive components, various chromatographic separations of the organic fractions from Filipendula glaberrima leaves led to the isolation of a new ellagitannin and a triterpenoid, along with 26 known compounds. The structures of the isolates were determined based on their spectroscopic properties and chemical evidence, which were then evaluated for their antioxidant activities, inhibitory activities on 3-hydroxy-3-methylglutaryl-coenzyme A reductase, and foam cell formation in THP-1 cells to prevent atherosclerosis. Rugosin B methyl ester (1) showed the best HMG-CoA reductase inhibition and significantly reduced ox-low-density lipoprotein-induced THP-1 macrophage-derived foam cell formation at 25 µM. In addition, no cytotoxicity was observed in THP-1 cells at 50 μg/mL of all extracts in the macrophage foam cell formation assay. Therefore, F. glaberrima extract containing 1 is promising in the development of dietary supplements due to its potential behavior as a novel source of nutrients for preventing and treating atherosclerosis. [ABSTRACT FROM AUTHOR]

This paper explores the emerging subject of extracting tannins from various plant sources using deep eutectic solvents (DESs). Tannins are widely used in the food and feed industries as they have outstanding antioxidant qualities and greatly enhance the flavor and nutritional content of a wide range of food products. Organic solvents are frequently used in traditional extraction techniques, which raises questions about their safety for human health and the environment. DESs present a prospective substitute because of their low toxicity, adaptability, and environmental friendliness. The fundamental ideas supporting the application of DESs in the extraction of tannins from a range of plant-based materials frequently used in daily life are all well covered in this paper. Furthermore, this paper covers the impact of extraction parameters on the yield of extracted tannins, as well as possible obstacles and directions for future research in this emerging subject. This includes challenges such as high viscosity, intricated recovery of compounds, thermal degradation, and the occurrence of esterification. An extensive summary of the diversity, structure, biosynthesis, distribution, and roles of tannins in plants is given in this paper. Additionally, this paper thoroughly examines various bioactivities of tannins and their metabolites.

In our search for bioactive components, various chromatographic separations of the organic fractions from Filipendula glaberrima leaves led to the isolation of a new ellagitannin and a triterpenoid, along with 26 known compounds. The structures of the isolates were determined based on their spectroscopic properties and chemical evidence, which were then evaluated for their antioxidant activities, inhibitory activities on 3-hydroxy-3-methylglutaryl-coenzyme A reductase, and foam cell formation in THP-1 cells to prevent atherosclerosis. Rugosin B methyl ester (1) showed the best HMG-CoA reductase inhibition and significantly reduced ox-low-density lipoprotein-induced THP-1 macrophage-derived foam cell formation at 25 µM. In addition, no cytotoxicity was observed in THP-1 cells at 50 μg/mL of all extracts in the macrophage foam cell formation assay. Therefore, F. glaberrima extract containing 1 is promising in the development of dietary supplements due to its potential behavior as a novel source of nutrients for preventing and treating atherosclerosis.

Light exposure of white wine can cause a light-struck taste (LST), a fault induced by riboflavin (RF) and methionine (Met) leading to the formation of volatile sulfur compounds (VSCs), including methanethiol (MeSH) and dimethyl disulfide (DMDS). The study aimed to investigate the impact of different antioxidants, i.e., sulfur dioxide (SO2), glutathione (GSH) and chestnut tannins (CT), on preventing LST in model wine (MW) and white wine (WW), both containing RF and Met. Both MW and WW samples were added with the antioxidants, either individually or in different combinations, prior to 2-h light exposure and they were stored in the dark for 24 months. As expected, the light induced the degradation of RF in all the conditions assayed. Met also decreased depending on the antioxidants added. The presence of antioxidants limited the formation of LST as lower concentrations of VSCs were found in both MW and WW samples. In the latter matrix, neither MeSH nor DMDS were detected in the presence of CT, while only DMDS was found in WW+GSH, WW+SO2+GSH and WW+CT+SO2 samples at a concentration lower than the perception thresholds. Considering the antioxidants individually, the order of their effectiveness was CT ≥ GSH > SO2 in WW under the adopted experimental conditions. The results indicate tannins as an effective enological tool for preventing LST in white wine and their use will be further investigated in different white wines under industrial scale.

Jaboticaba is a Brazilian native berry described as a rich source of phenolic compounds (PC) with health promoting effects. PC from jaboticaba peel powder (JPP) have low intestinal bio-accessibility and are catabolized by gut microbiota. However, the biological implication of PC-derived metabolites produced during JPP digestion remains unclear. This study aimed to evaluate the antiproliferative effects of colonic fermented JPP (FJPP) in a 3D model of colorectal cancer (CRC) composed by HT29 spheroids. JPP samples fermented with human feces during 0, 2, 8, 24 or 48 h were incubated (10,000 µg mL−1) with spheroids, and cell viability was assessed after 72 h. Chemometric analyses (cluster and principal component analyses) were used to identify the main compounds responsible for the bioactive effect. The antiproliferative effect of FJPP in the CRC 3D model was increased between 8 h and 24 h of incubation, and this effect was associated with HHDP-digalloylglucose isomer and dihydroxyphenyl-γ-valerolactone. At 48 h of fermentation, the antiproliferative effect of FJPP was negligible, indicating that the presence of urolithins did not improve the bioactivity of JPP. These findings provide relevant knowledge on the role of colonic microbiota fermentation to generate active phenolic metabolites from JPP with positive impact on CRC.

Hydrolysable tannins (HTs) are useful secondary metabolites that are responsible for pharmacological activities and astringent taste, flavor, and quality in fruits. They are also the main polyphenols in Canarium album L. (Chinese olive) fruit, an interesting and functional fruit that has been cultivated for over 2000 years. The HT content of C. album fruit was 2.3–13 times higher than that of berries with a higher content of HT. 1-galloyl-β-d-glucose (βG) is the first intermediate and the key metabolite in the HT biosynthesis pathway. It is catalyzed by UDP-glucosyltransferases (UGTs), which are responsible for the glycosylation of gallic acid (GA) to form βG. Here, we first reported 140 UGTs in C. album. Phylogenetic analysis clustered them into 14 phylogenetic groups (A, B, D–M, P, and Q), which are different from the 14 typical major groups (A~N) of Arabidopsis thaliana. Expression pattern and correlation analysis showed that UGT84A77 (Isoform0117852) was highly expressed and had a positive correlation with GA and βG content. Prokaryotic expression showed that UGT84A77 could catalyze GA to form βG. These results provide a theoretical basis on UGTs in C. album, which will be helpful for further functional research and availability on HTs and polyphenols.

Both condensed and hydrolysable tannins represent versatile natural polyphenolic structures exhibiting a broad range of activities that could be exploited in various fields including nutraceutics, cosmesis, consumer care, household and pharmaceutical applications. Various tannins are commercially available nowadays for use in such application fields. We have analysed a representative selection of commercially available condensed and hydrolysable tannins for structural features and purity. Using a combination of quantitative 31P NMR spectroscopy, HSQC measurements, MALDI-ToF analyses, gel permeation chromatography and wet chemical analysis, detailed structural characterisations and descriptions were possible, allowing for verification and falsification of claimed structural features.

The partition coefficients (logP) between n-octanol and water of 47 purified and characterized hydrolysable tannins were measured with the shake flask method utilizing UPLC and HPLC with UV detection. Results show that galloyl glucoses and gallotannins are clearly more hydrophobic than ellagitannins but the differences in hydrophobicity within ellagitannins are more varied than within galloyl glucoses or gallotannins. Most notable structural features that were found to influence the hydrophobicity of ellagitannins were the number of free galloyl groups, acyclic versus cyclic polyol, substitution of the anomeric position of glucose and 4C1 versus 1C4 conformation of the glucopyranose core.

In this study, we tested the growth inhibition effect of 22 individual ellagitannins and of pentagalloylglucose on four bacterial species, i.e., Clostridiales perfringens, Escherichia coli, Lactobacillus plantarum and Staphylococcus aureus. All tested compounds showed antimicrobial effects against S. aureus, and almost all against E. coli and C. perfringens. For L. plantarum, no or very weak growth inhibition was detected. The level of inhibition was the greatest for S. aureus and the weakest for C. perfringens. For S. aureus, the molecular size or flexibility of ellagitannins did not show a clear relationship with their antimicrobial activity, even though rugosins E and D and pentagalloylglucose with four or five free galloyl groups had a stronger growth inhibition effect than the other ellagitannins with glucopyranose cores but with less free galloyl groups. Additionally, our results with S. aureus showed that the oligomeric linkage of ellagitannin might have an effect on its antimicrobial activity. For E. coli, the molecular size, but not the molecular flexibility, of ellagitannins seemed to be an important factor. For C. perfringens, both the molecular size and the flexibility of ellagitannin were important factors. In previous studies, corilagin was used as a model for ellagitannins, but our results showed that other ellagitannins are much more efficacious; therefore, the antimicrobial effects of ellagitannins could be more significant than previously thought.

A bio-guided study of leaf extracts allowed the isolation of two new macrobicyclic hydrolysable tannins, namely merianin A (1) and merianin B (2), and oct-1-en-3-yl β-xylopyranosyl-(1„-6’)-β-glucopyranoside (3) from Meriania hernandoi, in addition to 11 known compounds reported for the first time in the Meriania genus. The structures were elucidated by spectroscopic analyses including one- and two-dimensional NMR techniques and mass spectrometry. The bioactivities of the compounds were determined by measuring the DPPH radical scavenging activity and by carrying out antioxidant power assays (FRAP), etiolated wheat coleoptile assays and phytotoxicity assays on the standard target species Lycopersicum esculentum W. (tomato). Compounds 1 and 2 exhibited the best free radical scavenging activities, with FRS50 values of 2.0 and 1.9 µM, respectively.

Activity-guided isolation of 80% acetone extract of Cornus alba, which is traditionally used as an anti-inflammatory, hemostatic and diuretic in Korea, yielded one novel compound, tentatively designated cornusiin H (13), together with 12 known compounds. The known compounds included four flavonoids (catechin (1), quercetin-3-O-β-D-glucuronide (2), quercetin-3-O-β-D-glucopyranoside (3), kaempferol-3-O-β-D-glucopyranoside (4)) and eight hydrolysable tannins (gallic acid (5), 2,6-di-O-galloyl-hamamelofuranoside (6), 2-galloyl-4-caffeoyl-L-threonic acid (7) 2,3-di-O-galloyl-4-caffeoyl-Lthreonic acid (8), 1,2,3,4,6-penta-O-galloyl-β-D-glucopyranoside (9), cornusiin B (10), cornusiin A (11) and camptothin B (12)). All compounds exhibited potent 1,1-diphenyl-2-picrylhydrazyl (DPPH)-free radical scavenging activity. Especially, the radical scavenging activities of 6 and 9-13 were higher than that of vitamin C. Compounds 9, 11, 12 and 13 inhibited the production of nitric oxide (NO) in lipopolysaccharide-stimulated RAW264.7 cells to the same degree as NG-Monomethyl-L-arginine (L-NMMA). When the antiproliferative effects of the isolated compounds were assessed in prostate cancer cells, the dimeric ellagitannins (11-13) selectively inhibited LNCaP hormone-dependent prostate cancer cells. Flow cytometry analysis indicated that the dimeric ellagitannins induced apoptosis and S-phase arrest. These results suggest that dimeric ellagitannins from Cornus alba can be developed as functional materials or herbal medicines for prostate tumors such as benign prostate hyperplasia and early-stage prostate cancer. [ABSTRACT FROM AUTHOR]

Light exposure of white wine can cause a light-struck taste (LST), a fault induced by riboflavin (RF) and methionine (Met) leading to the formation of volatile sulfur compounds (VSCs), including methanethiol (MeSH) and dimethyl disulfide (DMDS). The study aimed to investigate the impact of different antioxidants, i.e., sulfur dioxide (SO2), glutathione (GSH) and chestnut tannins (CT), on preventing LST in model wine (MW) and white wine (WW), both containing RF and Met. Both MW and WW samples were added with the antioxidants, either individually or in different combinations, prior to 2-h light exposure and they were stored in the dark for 24 months. As expected, the light induced the degradation of RF in all the conditions assayed. Met also decreased depending on the antioxidants added. The presence of antioxidants limited the formation of LST as lower concentrations of VSCs were found in both MW and WW samples. In the latter matrix, neither MeSH nor DMDS were detected in the presence of CT, while only DMDS was found in WW+GSH, WW+SO2+GSH and WW+CT+SO2 samples at a concentration lower than the perception thresholds. Considering the antioxidants individually, the order of their effectiveness was CT ≥ GSH > SO2 in WW under the adopted experimental conditions. The results indicate tannins as an effective enological tool for preventing LST in white wine and their use will be further investigated in different white wines under industrial scale. [ABSTRACT FROM AUTHOR]

Hydrolysable tannins (HTs) are useful secondary metabolites that are responsible for pharmacological activities and astringent taste, flavor, and quality in fruits. They are also the main polyphenols in Canarium album L. (Chinese olive) fruit, an interesting and functional fruit that has been cultivated for over 2000 years. The HT content of C. album fruit was 2.3–13 times higher than that of berries with a higher content of HT. 1-galloyl-β-d-glucose (βG) is the first intermediate and the key metabolite in the HT biosynthesis pathway. It is catalyzed by UDP-glucosyltransferases (UGTs), which are responsible for the glycosylation of gallic acid (GA) to form βG. Here, we first reported 140 UGTs in C. album. Phylogenetic analysis clustered them into 14 phylogenetic groups (A, B, D–M, P, and Q), which are different from the 14 typical major groups (A~N) of Arabidopsis thaliana. Expression pattern and correlation analysis showed that UGT84A77 (Isoform0117852) was highly expressed and had a positive correlation with GA and βG content. Prokaryotic expression showed that UGT84A77 could catalyze GA to form βG. These results provide a theoretical basis on UGTs in C. album, which will be helpful for further functional research and availability on HTs and polyphenols. [ABSTRACT FROM AUTHOR]

Jaboticaba is a Brazilian native berry described as a rich source of phenolic compounds (PC) with health promoting effects. PC from jaboticaba peel powder (JPP) have low intestinal bio-accessibility and are catabolized by gut microbiota. However, the biological implication of PC-derived metabolites produced during JPP digestion remains unclear. This study aimed to evaluate the antiproliferative effects of colonic fermented JPP (FJPP) in a 3D model of colorectal cancer (CRC) composed by HT29 spheroids. JPP samples fermented with human feces during 0, 2, 8, 24 or 48 h were incubated (10,000 µg mL−1) with spheroids, and cell viability was assessed after 72 h. Chemometric analyses (cluster and principal component analyses) were used to identify the main compounds responsible for the bioactive effect. The antiproliferative effect of FJPP in the CRC 3D model was increased between 8 h and 24 h of incubation, and this effect was associated with HHDP-digalloylglucose isomer and dihydroxyphenyl-γ-valerolactone. At 48 h of fermentation, the antiproliferative effect of FJPP was negligible, indicating that the presence of urolithins did not improve the bioactivity of JPP. These findings provide relevant knowledge on the role of colonic microbiota fermentation to generate active phenolic metabolites from JPP with positive impact on CRC. [ABSTRACT FROM AUTHOR]

Both condensed and hydrolysable tannins represent versatile natural polyphenolic structures exhibiting a broad range of activities that could be exploited in various fields including nutraceutics, cosmesis, consumer care, household and pharmaceutical applications. Various tannins are commercially available nowadays for use in such application fields. We have analysed a representative selection of commercially available condensed and hydrolysable tannins for structural features and purity. Using a combination of quantitative 31P NMR spectroscopy, HSQC measurements, MALDI-ToF analyses, gel permeation chromatography and wet chemical analysis, detailed structural characterisations and descriptions were possible, allowing for verification and falsification of claimed structural features. [ABSTRACT FROM AUTHOR]

The partition coefficients (logP) between n-octanol and water of 47 purified and characterized hydrolysable tannins were measured with the shake flask method utilizing UPLC and HPLC with UV detection. Results show that galloyl glucoses and gallotannins are clearly more hydrophobic than ellagitannins but the differences in hydrophobicity within ellagitannins are more varied than within galloyl glucoses or gallotannins. Most notable structural features that were found to influence the hydrophobicity of ellagitannins were the number of free galloyl groups, acyclic versus cyclic polyol, substitution of the anomeric position of glucose and 4C1 versus 1C4 conformation of the glucopyranose core. [ABSTRACT FROM AUTHOR]

A bio-guided study of leaf extracts allowed the isolation of two new macrobicyclic hydrolysable tannins, namely merianin A (1) and merianin B (2), and oct-1-en-3-yl β-xylopyranosyl-(1"-6')-β-glucopyranoside (3) from Meriania hernandoi, in addition to 11 known compounds reported for the first time in the Meriania genus. The structures were elucidated by spectroscopic analyses including one- and two-dimensional NMR techniques and mass spectrometry. The bioactivities of the compounds were determined by measuring the DPPH radical scavenging activity and by carrying out antioxidant power assays (FRAP), etiolated wheat coleoptile assays and phytotoxicity assays on the standard target species Lycopersicum esculentum W. (tomato). Compounds 1 and 2 exhibited the best free radical scavenging activities, with FRS50 values of 2.0 and 1.9 µM, respectively. [ABSTRACT FROM AUTHOR]