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The protective role of (poly)phenols against metabolic disorders has been extensively studied in adults but not in adolescents. To assess associations of dietary (poly)phenols and their subclasses with cardiometabolic health parameters in adolescents. A cross-sectional study was conducted in 944 individuals aged 11–14 years enrolled in the SI! Program for Secondary Schools trial (NCT03504059). (Poly)phenol intake was assessed using semi-quantitative food frequency questionnaires and the Phenol-Explorer database. The measured cardiometabolic parameters were waist circumference (WC) age-sex Z-score, blood pressure (BP) age-sex Z-score, blood glucose (BG), triglycerides (TG), and high-density lipoprotein cholesterol (HDL-c). Multilevel mixed-effect linear regression models were applied to examine the association between (poly)phenol quintiles and cardiometabolic health parameters. Compared to the lowest quintile, adolescents in the highest quintile of total (poly)phenol intake had lower WC Z-scores, mean arterial pressure Z-scores, and HDL-c after multivariable adjustment. The WC Z-scores and HDL-c were lower in the highest quintile of flavonoid intake compared to the lowest quintile. The highest quintile of phenolic acid intake was associated with a lower WC Z-score and TG levels, and the highest quintile of stilbene intake with lower BG and TG, and with higher HDL-c compared to the lowest quintile. A higher intake of (poly)phenols, especially flavonoids, phenolic acids, and stilbenes, was associated with better cardiometabolic parameters in adolescents.

The Russian Far East is a region of unique biodiversity, with numerous plant species, including Reynoutria japonica and Reynoutria sachalinensis. These plants are considered a serious threat to biodiversity and are classified as threatened species. However, Reynoutria plants synthesize and accumulate a variety of metabolites that are valued for their positive effects on human health. The main objective of this study is to quantitatively and qualitatively evaluate the content of secondary metabolites in different parts of R. japonica and R. sachalinensis plants. In this study, the results of phylogenetic analysis of the ITS2, matK, and rps16 genes showed that samples collected in the Sakhalin region were closest to R. sachalinensis, while samples collected in Primorsky krai were closer to R. japonica. The high-performance chromatography and mass spectrometry (HPLC-MS/MS) method was used to identify the compounds. As a result of the identification of metabolites in the leaves, stem, and roots of R. japonica and R. sachalinensis, we showed the presence of a total of 31 compounds, including stilbenes, phenolic acids, flavan-3-ols, flavones and flavonols, naphthalene derivatives, anthraquinones and derivatives, and phenylpropanoid disaccharide esters. The root of R. japonica was shown to be a rich source of stilbenes (up to 229.17 mg/g DW), which was 8.5 times higher than that of R. sachalinensis root (up to 27.04 mg/g DW). The root also contained high amounts of emodin derivatives and vanicoside B. Quercetin and its derivatives were the major metabolites in the leaves and stems of both Reynoutria species. In R. japonica leaves, quercetin-3-O-pentoside was the major compound, reaching a total of 7 mg/g DW, accounting for 34% of all compounds analyzed. In contrast, in R. sachalinensis leaves, quercitrin was the major compound (up to 13.96 mg/g DW), accounting for 62% of all compounds and 12.7 times higher than in R. japonica leaves. In turn, R. japonica leaves also contained high amounts of phenolic acids (up to 10 mg/g DW). Thus, the obtained results showed significant differences in the qualitative and quantitative composition of metabolites between R. japonica and R. sachalinensis plants. Additionally, in this work, a cell culture of R. japonica was obtained and tested for its ability to synthesize and accumulate stilbenes. [ABSTRACT FROM AUTHOR]

Flavan-3-ols are plant secondary metabolites that play important roles in stress resistance. Our previous studies revealed that salicylic acid (SA) activates R2R3-MYB transcription factors, promoting flavan-3-ol biosynthesis. This study identified two R2R3-MYB genes that exhibited positive responses to both exogenous SA and were probably involved in flavan-3-ol biosynthesis through RNA-sequencing, functional enrichment analysis, and qRT-PCR. The results indicated that the contents of total flavan-3-ols and their monomers, (+)-catechin and (−)-epicatechin, in grape berries after exogenous SA application were substantially increased compared to those in the control. A total of 683 differentially expressed genes in response to exogenous SA treatment were identified using RNA-seq. KEGG analysis revealed enrichment of the 'flavonoid biosynthesis' and 'plant hormone signal transduction' pathways. A specific module highly associated with flavan-3-ol biosynthesis was identified by constructing a co-expression network. Two candidate genes (VvMYB108B and VvMYB145) likely participating in flavan-3-ol biosynthesis were selected using qRT-PCR. Therefore, these two potential genes that respond to SA and putatively participate in flavan-3-ol biosynthesis were identified for the first time. These results lay a solid basis for a more profound understanding of the molecular regulation of flavan-3-ol biosynthesis in grapes. [ABSTRACT FROM AUTHOR]

Beverages are an important part of the food sector their storage is also one of the most critical issues. This study investigated the effects of different storage temperatures and times on physicochemical properties, flavonoid and organic acid contents of soda, sherbet and ice tea produced by adding sour grape concentrate. Changes in the flavan-3-ol content of ice tea were also measured during the storage period. The beverages were stored in three different conditions, cold storage (~4°C), room temperature (~24°C) and controlled storage (20±1°C), for six months and analyzed every two months. Storage temperatures and time affected the total soluble solids and acidities of the beverages (p≤0.05). Tartaric acid decreased during storage, especially during the first two months in sherbets. Ice tea and soda drinks were found more stable than sherbets. The malic acid was found the major organic acid in beverages. Flavonoid content in ice tea was higher than others. The flavonoid concentrations of ice tea stored at 20 and 24°C and of sherbet at 4°C were statistically significant as a function of storage time while these values were not significant for ice tea stored at 4°C and of sherbet at 20 and 24°C (p≤0.05) . Concentrations of flavan-3-ols varied with storage conditions. The levels of epicatechin, epigallocatechin and epigallocatechin gallate in ice tea samples decreased between an average of 43.72 and 71.15% at the end of six months of storage. Principal component analysis separated two months storage from other storage periods and perfectly discriminated the studied flavan-3-ols except catechin. Soluble solid and brix-acid ratio also dissociated similarly to flavan-3-ols. [ABSTRACT FROM AUTHOR]

Asynchronous ripening is a significant challenge in winemaking. Green berries reduce alcohol and pH while increasing acidity. Green berries are rich in bitter and astringent compounds, with an unknown impact on wine quality. The aim of this study was to evaluate the impact of harvest date and vineyard location on the polyphenolic composition of Plavac Mali wines in Dalmatia, Croatia. Experiments were conducted in two locations, Split and Zadar, producing fifteen wines per location from four harvest dates (H1–H4), including green berry wines from H1. The first harvest date occurred 27 days after véraison (DAV) and the last at 69 DAV, corresponding to overripeness. Green berry wines of H1 had low alcohol content up to 4.4% (v/v) in Split. Epigallocatechin was the main flavonoid in those wines, followed by dimer B1 in Split and catechin in Zadar. Green wines from Split had a higher concentration of phenolic acids, flavan-3-ol monomers and dimers. Wines of H3 had the highest concentration of malvidin-3-O-glucoside. With a later harvest date, a dramatic decrease in catechin and dimers was observed in wines from Split, and a decrease in epicatechin, epigallocatechin and dimer B1 in those from Zadar. The final expression of the physiochemical and polyphenolic composition of Plavac Mali wine is determined by the dynamics of harvest date, location and their interactions. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases (CVDs) are one of the main causes of mortality and morbidity worldwide. A healthy diet rich in plant-derived compounds such as (poly)phenols appears to have a key role in improving cardiovascular health. Flavan-3-ols represent a subclass of (poly)phenols of great interest for their possible health benefits. In this review, we summarized the results of clinical studies on vascular outcomes of flavan-3-ol supplementation and we focused on the role of the microbiota in CVD. Clinical trials included in this review showed that supplementation with flavan-3-ols mostly derived from cocoa products significantly reduces blood pressure and improves endothelial function. Studies on catechins from green tea demonstrated better results when involving healthy individuals. From a mechanistic point of view, emerging evidence suggests that microbial metabolites may play a role in the observed effects. Their function extends beyond the previous belief of ROS scavenging activity and encompasses a direct impact on gene expression and protein function. Although flavan-3-ols appear to have effects on cardiovascular health, further studies are needed to clarify and confirm these potential benefits and the rising evidence of the potential involvement of the microbiota. [ABSTRACT FROM AUTHOR]

Guideline recommendation for a plant bioactive such as flavan-3-ols is a departure from previous recommendations because it is not based on deficiencies but rather improvement in health outcomes. Nevertheless, there is a rapidly growing body of clinical data reflecting benefits of flavan-3-ol intake that outweigh potential harms. Thus, the objective of the Expert Panel was to develop an intake recommendation for flavan-3-ols and cardiometabolic outcomes to inform multiple stakeholders including clinicians, policymakers, public health entities, and consumers. Guideline development followed the process set forth by the Academy of Nutrition and Dietetics, which includes use of the Evidence to Decision Framework. Studies informing this guideline (157 randomized controlled trials and 15 cohort studies) were previously reviewed in a recently published systematic review and meta-analysis. Quality and strength-of-evidence along with risk-of-bias in reporting was reviewed. In drafting the guideline, data assessments and opinions by authoritative scientific bodies providing guidance on the safety of flavan-3-ols were considered. Moderate evidence supporting cardiometabolic protection resulting from flavan-3-ol intake in the range of 400-600 mg/d was supported in the literature. Further, increasing consumption of dietary flavan-3-ols can help improve blood pressure, cholesterol concentrations, and blood sugar. Strength of evidence was strongest for some biomarkers (i.e., systolic blood pressure, total cholesterol, HDL cholesterol, and insulin/glucose dynamics). It should be noted that this is a food-based guideline and not a recommendation for flavan-3-ol supplements. This guideline was based on beneficial effects observed across a range of disease biomarkers and endpoints. Although a comprehensive assessment of available data has been reviewed, evidence gaps identified herein can inform scientists in guiding future randomized clinical trials.

SUMMARY: Flavan‐3‐ols are prominent phenolic compounds found abundantly in the young leaves of tea plants. The enzymes involved in flavan‐3‐ol biosynthesis in tea plants have been extensively investigated. However, the localization and associations of these numerous functional enzymes within cells have been largely neglected. In this study, we aimed to investigate the synthesis of flavan‐3‐ols in tea plants, particularly focusing on epigallocatechin gallate. Our analysis involving the DESI‐MSI method to reveal a distinct distribution pattern of B‐ring trihydroxylated flavonoids, primarily concentrated in the outer layer of buds. Subcellular localization showed that CsC4H, CsF3′H, and CsF3′5′H localizes endoplasmic reticulum. Protein–protein interaction studies demonstrated direct associations between CsC4H, CsF3′H, and cytoplasmic enzymes (CHS, CHI, F3H, DFR, FLS, and ANR), highlighting their interactions within the biosynthetic pathway. Notably, CsF3′5′H, the enzyme for B‐ring trihydroxylation, did not directly interact with other enzymes. We identified cytochrome b5 isoform C serving as an essential redox partner, ensuring the proper functioning of CsF3′5′H. Our findings suggest the existence of distinct modules governing the synthesis of different B‐ring hydroxylation compounds. This study provides valuable insights into the mechanisms underlying flavonoid diversity and efficient synthesis and enhances our understanding of the substantial accumulation of B‐ring trihydroxylated flavan‐3‐ols in tea plants. Significance Statement: Our work reveals the mechanism of flavonoid diversity and efficient synthesis in tea plants from the perspective of metabolon. Different metabolons modules provide a new perspective on the scientific problem of why tea plants accumulate high levels of EGCG. The discovery of obligate electron shuttle proteins provides new directions for improving metabolic engineering. [ABSTRACT FROM AUTHOR]

(-)-Epicatechin (EC), a primary form of flavan-3ol and a building block of proanthocyanidins, has health benefits as it is a potent antioxidant. So far, no quantitative trait loci (QTLs) associated with EC have yet been identified in soybean. In this study, QTLs for EC and hilum color were identified in recombinant inbred lines (RILs) derived from the varieties Jinpung and IT109098 using high-resolution single nucleotide polymorphism linkage mapping. This revealed two major QTLs for EC content, qEC06 and qEC08. qEC06 spanned the Tawny (T) locus encoding flavonoid 3′-hydroxylase. qEC08, located near the Inhibitor (I) locus on Chr08, was also a major QTL for hilum color; however, allelic stacking of qEC08 and I revealed no relationship between I and EC content. RILs with IT109098 alleles at both qEC06 and qEC08 had higher EC content than other lines. These results will enable the production of soybean varieties with high EC content via marker-assisted selection. [ABSTRACT FROM AUTHOR]

The present investigation delved into the pharmacological mechanisms underlying the management of depression through Flavan-3-ols and Aromatic Resins, employing in silico and in vivo methodologies. Network pharmacology was utilized to identify targets associated with the antidepressant activity of Flavan-3-ols and Aromatic Resins. Protein-protein interaction and KEGG analyses were conducted to enrich and explore key pathways. Molecular docking and simulation studies were executed to assess the targets. The antidepressant effects were studied using the Forced Swim Test and Tail Suspension Test on both unstressed mice and those subjected to the chronic unpredictable mild stress (CUMS) paradigm. The Compound-Target network analysis revealed a substantial impact of the components on numerous targets, with 332 nodes and 491 edges. Protein-protein interaction analysis indicated significant interactions with targets implicated in depression. KEGG analysis highlighted major pathways, including neuroactive ligand-receptor interaction, dopaminergic synapse, and long-term depression. Docking studies on EGCG demonstrated binding energies of -7.2 kcal/mol for serotonin 1 A (5-HT1A), -7.9 kcal/mol for D2, and − 9.6 kcal/mol for MOA-A. Molecular dynamics simulation indicated minute fluctuation, hence suggesting stable complexes formed between small molecules and proteins. The combination of Flavan-3-ols and Aromatic Resins significantly increased mobility time (p < 0.05) in the Forced Swim Test and Tail Suspension Test, while significantly decreasing immobility time and time freezing (p < 0.05) in both unstressed and CUMS mice. This study demonstrated the antidepressant characteristics of Flavan-3-ols and Aromatic Resins, underscoring the need for further research to develop a novel antidepressant medication. [ABSTRACT FROM AUTHOR]

Proanthocyanidins, natural polyphenolic compounds abundantly present in plants, exhibit diverse bioactivities, including antioxidative, anti-inflammatory, and antibacterial effects. These bioactivities are intricately linked to the degree of polymerization of these compounds. Through a comprehensive analysis of recent domestic and international research, this article synthesizes the latest advancements in the extraction process, degradation methods, as well as the biological activities and underlying mechanisms of proanthocyanidins. Furthermore, future research endeavors should prioritize the refinement of extraction techniques, the elucidation of bioactive mechanisms, and the development of formulations with enhanced potency. This will maximize the utilization of proanthocyanidins across diverse applications. [ABSTRACT FROM AUTHOR]

Flavonoids from green and black tea may benefit cardiovascular health. Brewed tea consumption and flavonoid intake in France have not been previously explored. This study assessed the dietary intake of flavonoids among French children and adults, using 3 days' dietary recall for 3896 persons aged >4 y in the Third French Individual and National Food Consumption Survey (INCA3). Foods consumed by INCA 3 participants were manually matched with the flavonoid content of foods from the French PhenolExplorer database and the US Department of Agriculture expanded flavonoid database (2018 version). The six subclasses of flavonoids were flavan-3-ols, flavanones, anthocyanidins, flavonols, flavones, and isoflavones. Flavonoid intake was stratified by age subgroups (children and adults separately) and examined using socio-demographics and tea consumption patterns. Mean flavonoid intake was 210 mg/d. Flavonoids in the French diet were predominantly flavan-3-ols (147 mg/d), of which tea is the main source. The effects of age, education, income, and socio-professional category (SPC) on flavonoid intake were all significant (p < 0.0001). Brewed tea consumers were 31.88% of French adults and 3.79% of children. Brewed tea consumption and flavonoid intake were highly correlated. The highest brewed tea and flavonoid intakes were found among individuals with the highest SPC and education levels. Flavonoid intake in France was associated with brewed tea consumption and with higher education and income. [ABSTRACT FROM AUTHOR]

Naturally colored cotton (NCC) offers an environmentally friendly fiber for textile applications. Processing white cotton fiber into textiles requires extensive energy, water, and chemicals, whereas processing of NCC skips the most polluting activity, scouring-bleaching and dyeing; therefore, NCC provides an avenue to minimize the harmful impacts of textile production. NCC varieties are suitable for organic agriculture since they are naturally insect and disease-resistant, salt and drought-tolerant. Various fiber shades, ranging from light green to tan and brown, are available in the cultivated NCC (Gossypium hirsutum L.) species. The pigments responsible for the color of brown cotton fiber are proanthocyanidins or their derivatives synthesized by the flavonoid pathway. Due to pigments, the NCC has excellent ultraviolet protection properties. Some brown cotton varieties exhibited superior thermal resistance of fiber that can be used to make fabrics with enhanced flame retardancy. Here, we review molecular mechanisms involved in the pigment production of brown cotton and challenges in breeding NCC varieties with a wide range of colors but without penalty in fiber quality. Also, we discuss opportunities for NCC with flame-retarding properties in textile applications. [ABSTRACT FROM AUTHOR]

Abstract Background and aims Flavonoids are a class of secondary plant metabolites that have been shown to have multiple health benefits, including antioxidant and anti-inflammatory. This study was to explore the association between dietary flavonoid consumption and the prevalence of chronic respiratory diseases (CRDs) in adults. Methods and results The six main types of flavonoids, including isoflavones, anthocyanidins, flavan-3-ols, flavanones, flavones, and flavonols, were obtained from the National Health and Nutrition Examination Survey (NHANES) 2007–2010 and 2017–2018 by the two 24-h recall interviews. The prevalence of CRDs, including asthma, emphysema, and chronic bronchitis, was determined through a self-administered questionnaire. The analysis included 15,753 participants aged 18 years or older who had completed a diet history interview. After adjustment for potential confounders, the inverse link was found with total flavonoids, anthocyanidins, flavanones, and flavones, with an OR (95%CI) of 0.86 (0.75–0.98), 0.84 (0.72–0.97), 0.80(0.69–0.92), and 0.85(0.73–0.98) for the highest group compared to the lowest group. WQS regression revealed that the mixture of flavonoids was negatively linked with the prevalence of CRDs (OR = 0.88 [0.82–0.95], P

The Russian Far East is a region of unique biodiversity, with numerous plant species, including Reynoutria japonica and Reynoutria sachalinensis. These plants are considered a serious threat to biodiversity and are classified as threatened species. However, Reynoutria plants synthesize and accumulate a variety of metabolites that are valued for their positive effects on human health. The main objective of this study is to quantitatively and qualitatively evaluate the content of secondary metabolites in different parts of R. japonica and R. sachalinensis plants. In this study, the results of phylogenetic analysis of the ITS2, matK, and rps16 genes showed that samples collected in the Sakhalin region were closest to R. sachalinensis, while samples collected in Primorsky krai were closer to R. japonica. The high-performance chromatography and mass spectrometry (HPLC-MS/MS) method was used to identify the compounds. As a result of the identification of metabolites in the leaves, stem, and roots of R. japonica and R. sachalinensis, we showed the presence of a total of 31 compounds, including stilbenes, phenolic acids, flavan-3-ols, flavones and flavonols, naphthalene derivatives, anthraquinones and derivatives, and phenylpropanoid disaccharide esters. The root of R. japonica was shown to be a rich source of stilbenes (up to 229.17 mg/g DW), which was 8.5 times higher than that of R. sachalinensis root (up to 27.04 mg/g DW). The root also contained high amounts of emodin derivatives and vanicoside B. Quercetin and its derivatives were the major metabolites in the leaves and stems of both Reynoutria species. In R. japonica leaves, quercetin-3-O-pentoside was the major compound, reaching a total of 7 mg/g DW, accounting for 34% of all compounds analyzed. In contrast, in R. sachalinensis leaves, quercitrin was the major compound (up to 13.96 mg/g DW), accounting for 62% of all compounds and 12.7 times higher than in R. japonica leaves. In turn, R. japonica leaves also contained high amounts of phenolic acids (up to 10 mg/g DW). Thus, the obtained results showed significant differences in the qualitative and quantitative composition of metabolites between R. japonica and R. sachalinensis plants. Additionally, in this work, a cell culture of R. japonica was obtained and tested for its ability to synthesize and accumulate stilbenes.

Flavan-3-ols are plant secondary metabolites that play important roles in stress resistance. Our previous studies revealed that salicylic acid (SA) activates R2R3-MYB transcription factors, promoting flavan-3-ol biosynthesis. This study identified two R2R3-MYB genes that exhibited positive responses to both exogenous SA and were probably involved in flavan-3-ol biosynthesis through RNA-sequencing, functional enrichment analysis, and qRT-PCR. The results indicated that the contents of total flavan-3-ols and their monomers, (+)-catechin and (−)-epicatechin, in grape berries after exogenous SA application were substantially increased compared to those in the control. A total of 683 differentially expressed genes in response to exogenous SA treatment were identified using RNA-seq. KEGG analysis revealed enrichment of the ‘flavonoid biosynthesis’ and ‘plant hormone signal transduction’ pathways. A specific module highly associated with flavan-3-ol biosynthesis was identified by constructing a co-expression network. Two candidate genes (VvMYB108B and VvMYB145) likely participating in flavan-3-ol biosynthesis were selected using qRT-PCR. Therefore, these two potential genes that respond to SA and putatively participate in flavan-3-ol biosynthesis were identified for the first time. These results lay a solid basis for a more profound understanding of the molecular regulation of flavan-3-ol biosynthesis in grapes.

Background and aims: Flavonoids are a class of secondary plant metabolites that have been shown to have multiple health benefits, including antioxidant and anti-inflammatory. This study was to explore the association between dietary flavonoid consumption and the prevalence of chronic respiratory diseases (CRDs) in adults. Methods and results: The six main types of flavonoids, including isoflavones, anthocyanidins, flavan-3-ols, flavanones, flavones, and flavonols, were obtained from the National Health and Nutrition Examination Survey (NHANES) 2007–2010 and 2017–2018 by the two 24-h recall interviews. The prevalence of CRDs, including asthma, emphysema, and chronic bronchitis, was determined through a self-administered questionnaire. The analysis included 15,753 participants aged 18 years or older who had completed a diet history interview. After adjustment for potential confounders, the inverse link was found with total flavonoids, anthocyanidins, flavanones, and flavones, with an OR (95%CI) of 0.86 (0.75–0.98), 0.84 (0.72–0.97), 0.80(0.69–0.92), and 0.85(0.73–0.98) for the highest group compared to the lowest group. WQS regression revealed that the mixture of flavonoids was negatively linked with the prevalence of CRDs (OR = 0.88 [0.82–0.95], P < 0.01), and the largest effect was mainly from flavanones (weight = 0.41). In addition, we found that flavonoid intake was negatively linked with inflammatory markers, and systemic inflammation significantly mediated the associations of flavonoids with CRDs, with a mediation rate of 12.64% for CRP (P < 0.01). Conclusion: Higher flavonoid intake was related with a lower prevalence of CRDs in adults, and this relationship may be mediated through systemic inflammation. [ABSTRACT FROM AUTHOR]

Asynchronous ripening is a significant challenge in winemaking. Green berries reduce alcohol and pH while increasing acidity. Green berries are rich in bitter and astringent compounds, with an unknown impact on wine quality. The aim of this study was to evaluate the impact of harvest date and vineyard location on the polyphenolic composition of Plavac Mali wines in Dalmatia, Croatia. Experiments were conducted in two locations, Split and Zadar, producing fifteen wines per location from four harvest dates (H1–H4), including green berry wines from H1. The first harvest date occurred 27 days after véraison (DAV) and the last at 69 DAV, corresponding to overripeness. Green berry wines of H1 had low alcohol content up to 4.4% (v/v) in Split. Epigallocatechin was the main flavonoid in those wines, followed by dimer B1 in Split and catechin in Zadar. Green wines from Split had a higher concentration of phenolic acids, flavan-3-ol monomers and dimers. Wines of H3 had the highest concentration of malvidin-3-O-glucoside. With a later harvest date, a dramatic decrease in catechin and dimers was observed in wines from Split, and a decrease in epicatechin, epigallocatechin and dimer B1 in those from Zadar. The final expression of the physiochemical and polyphenolic composition of Plavac Mali wine is determined by the dynamics of harvest date, location and their interactions.

Naturally colored cotton (NCC) offers an environmentally friendly fiber for textile applications. Processing white cotton fiber into textiles requires extensive energy, water, and chemicals, whereas processing of NCC skips the most polluting activity, scouring-bleaching and dyeing; therefore, NCC provides an avenue to minimize the harmful impacts of textile production. NCC varieties are suitable for organic agriculture since they are naturally insect and disease-resistant, salt and drought-tolerant. Various fiber shades, ranging from light green to tan and brown, are available in the cultivated NCC (Gossypium hirsutum L.) species. The pigments responsible for the color of brown cotton fiber are proanthocyanidins or their derivatives synthesized by the flavonoid pathway. Due to pigments, the NCC has excellent ultraviolet protection properties. Some brown cotton varieties exhibited superior thermal resistance of fiber that can be used to make fabrics with enhanced flame retardancy. Here, we review molecular mechanisms involved in the pigment production of brown cotton and challenges in breeding NCC varieties with a wide range of colors but without penalty in fiber quality. Also, we discuss opportunities for NCC with flame-retarding properties in textile applications.

Continuing caution is required against the potential emergence of SARS-CoV-2 novel mutants that could pose the next global health and socioeconomical threats. If virus in saliva can be inactivated by a beverage, such a beverage may be useful because the saliva of infected persons is the major origin of droplets and aerosols that mediate human-to-human viral transmission. We previously reported that SARS-CoV-2 was significantly inactivated by treatment in vitro with tea including green tea and black tea. Catechins and its derived compounds galloylated theaflavins (gTFs) bound to the receptor-binding domain (RBD) of the S-protein and blocked interaction between RBD and ACE2. Black tea is often consumed with sugar, milk, lemon juice, etc., and it remains unclarified whether these ingredients may influence the anti-SARS-CoV-2 effect of black tea. Here, we examined the effect of black tea on Omicron subvariants in the presence of these ingredients. The infectivity of Omicron subvariants was decreased to 1/100 or lower after treatment with black tea for 10 s. One or two teaspoons of milk (4~8 mL) completely blocked the anti-viral effect of a cup of tea (125 mL), whereas an addition of sugar or lemon juice failed to do so. The suppressive effect was dose-dependently exerted by milk casein but not whey proteins. gTFs were coprecipitated with casein after acidification of milk-supplemented black tea, strongly suggesting the binding of gTFs to casein. The present study demonstrates for the first time that an addition of milk cancelled the anti-SARS-CoV-2 effect of black tea due to binding of casein to gTFs. [ABSTRACT FROM AUTHOR]

While the Saaz aromatic variety remains classified as a total-flavanoid-rich cultivar, no inverse correlation was found between total flavanoids and the α-acid content when the dual-purpose varieties Citra, CTZ, Amarillo, Eureka!, Mandarina Bavaria, Mosaic, Polaris, and Sabro were considered. The levels of hop flavan-3-ol monomers, dimers, and trimers (quantitated by HPLC-MS/MS) appeared strongly influenced by variety and harvest year. On the other hand, the catechin/epicatechin ratio (and B3/B2 ratio) proved stable within the same variety through two successive harvest years. Among the nine herein-investigated varieties, Citra and Saaz displayed notable catechin/epicatechin ratios (>3.7 compared to <1.6 for the others), whereas Polaris exhibited the lowest monomer content (less than 800 mg/kg). These distinctive profiles could impact the colloidal and color stability of hop-forward beers. [ABSTRACT FROM AUTHOR]

Stryphnodendron pulcherrimum is a plant found in the Brazilian Amazon and contains high content of catechin/(epi)catechin (flavan-3-ol) derivatives. The polymerization of this kind of flavan-3-ol generates condensed tannins, often associated to plant-based diets and gut microbiota. Thus, the discovery of condensed tannins from plants is a valuable approach once it enhances their availability from natural sources. Herein, we described a tetrameric condensed tannin (Molecular Mass 1,170 a.m.u.) tentatively identified for the first time in the barks from S. pulcherrimum. Condensed tannins-derived (flavan-3-ols units) are likely degraded in the gut, and their degradation products such as 3-hydroxyphenylacetic acid (OPAC), 3,4-dihydroxyphenylacetic acid (DHAA), 3-(3,4-dihydroxyphenyl)-propionic acid (DHPA), and 5-(3′,4′-dihydroxyphenyl)-γ-valerolactone (DHPV) could present benefits to gut microbiome metabolism. Therefore, this observational study represents a new insight into S. pulcherrimum, its molecules, and their potential benefits to avoid different diseases and gut well-functional.

This research assessed the phenolic composition of Jussara pulp from the Brazilian states of Minas Gerais (MG) and Espírito Santo (ES) using HPLC-DAD-MS/MS. Seventeen anthocyanins were detected in fruits, derived from cyanidin, pelargonidin and peonidin. Among the non-anthocyanic phenolic compounds, flavonols (kaempferol, quercetin and isorhamnetin derivatives), flavan-3-ols (catechin, epicatechin, B-type procyanidins and unknown dimers) and resveratrol in its glycosylated form have been identified. Catechin (32.41-60.56 mg 100g-1) and epicatechin (18.86-40.92 mg 100g-1) were the main flavan-3-ols present in the fruits. The samples showed small concentrations of resveratrol glycosides (0.02-0.91 mg 100g-1). The analytical methodology used (HPLC-DAD-ESI-MS/MS) permitted the identification of newly reported compounds in this fruit. [ABSTRACT FROM AUTHOR]

Avocado peel and seed are the main by-products of avocado processing and are considered as promising sources of phenolic compounds with biological activities. Thus, this research focuses on the establishment, for the first time, of ultrasound-assisted extraction of flavan-3-ols with high antioxidant activity from avocado peel and seed using a sonotrode. Indeed, 2 Box–Behnken designs were performed for 15 experiments, with each design having three independent factors (ratio ethanol/water (v/v), time (min) and amplitude (%)). In both models, the responses included total procyanidins (flavan-3-ols) measured via HPLC-FLD and antioxidant activity measured via DPPH, ABTS and FRAP. The results showed that applying the sonotrode extraction method could increase flavan-3-ols recovery by 54% and antioxidant activity by 62–76% compared to ultrasound bath technology. Therefore, this technology was demonstrated to be a non-thermal, low time-consuming and scalable method that allowed the recovery of flavan-3-ols from avocado by-products that could be used as functional ingredients. [ABSTRACT FROM AUTHOR]

This study aimed to determine structure–function relationships of monomeric and oligomeric flavan-3-ols (procyanidins) with respect to their antimicrobial activity and their inhibition of digestive enzymes. Monomeric flacan-3-ols were purchased as reference compounds; oligomeric procyanidins were extracted from grape seeds, separated by high-performance counter-current chromatography and characterized by LC-MS/MS. The antimicrobial activity against a broad range of intestinal microorganisms increased in the order catechin = epicatechin > epigallocatechin and oligomeric procyanidins > epigallocatechin gallate. Facultative anaerobes were highly resistant while strict anaerobes including Allobaculum sp. and Ruminococcus gnavus were 10 – 100 times more sensitive. The inhibition of digestive enzymes from the rat small intestine increased in the order catechin

Recent studies on natural antioxidant compounds have highlighted their potentiality against various pathological conditions. The present review aims to selectively evaluate the benefits of catechins and their polymeric structure on metabolic syndrome, a common disorder characterized by a cluster of three main risk factors: obesity, hypertension, and hyperglycemia. Patients with metabolic syndrome suffer chronic low inflammation state and oxidative stress both conditions effectively countered by flavanols and their polymers. The mechanism behind the activity of these molecules has been highlighted and correlated with the characteristic features present on their basic flavonoidic skelethon, as well as the efficient doses needed to perform their activity in both in vitro and in vivo studies. The amount of evidence provided in this review offers a starting point for flavanol dietary supplementation as a potential strategy to counteract several metabolic targets associated with metabolic syndrome and suggests a key role of albumin as flavanol-delivery system to the different target of action inside the organism. [ABSTRACT FROM AUTHOR]

Background and Objectives: Grape is one of the most important fruit products globally and has a high nutritional value with strong antioxidant and anti-cancer activity. Today, the use of healthy natural compounds, including organic nitrogen compounds, has become very important to improve the qualitative performance of fruits. The use of amino acids as one of the natural compounds of nitrogen can increase the nutritional values of fruit crops. In the present study, gamma aminobutyric acid was used as a non-protein amino acid to improve the quality characteristics of Qizil-Uzum grape fruit. Materials and Methods: The experiment was performed in two separate orchards located in two regions of Urmia city with different microclimatic conditions in a completely randomized design with GABA foliar application at 4 concentrations (0, 5, 10, 25 mM) in two stages (veraison stage and one week later) with 3 replications on 13-year-old cv. Qızıl Uzum grapevines. Some fruit quality characteristics include titratable acids (TA), total soluble solids (TSS), total antioxidant content, total phenol, total flavonoid, total anthocyanin, the activity of phenylalanine ammonialyase (PAL), catalase enzymes, phenolic compounds of fruit including flavonols, flavan-3-ols and phenolic acids, and also a relative expression of PAL and CHS genes were evaluated. Results: Based on the results, GABA at a concentration of 10 mM, caused the highest content of titratable acids, total soluble solids, total phenol, total flavonoids, total antioxidant and total anthocyanin of fruit. The highest activity of PAL enzyme was also observed at this concentration. Catalase enzyme had the maximum activity at 25 mM. The phenolic compounds that were measured by HPLC in this study included the flavonol compounds: myricetin, quercetin, kaempferol, syringetin; the flavan-3-ols compounds: catechin; and the non-flavonoid compounds: gallic acid, caffeic acid, p-coumaric acid and resveratrol, most of which had the highest level at 10 mM, followed by 5 mM GABA. Also, PAL and CHS genes had the highest expression at both sampling times (48 and 72 hours after foliar application) at the concentration of 10 mM GABA and their lowest expression was at the concentration of 25 mM GABA. Conclusion: This study showed that GABA at the concentration of 10 mM at the veraison stage and one week later had an effect on increasing fruit quality indicators, including total soluble sugars, as a basic substrate for the biosynthetic pathway of effective fruit quality compounds, and with effect on antioxidant content improvement, as well as enhancing the expression of related genes for PAL enzyme activity, as a key enzyme of the biosynthesis of the phenolic compound, can improve fruit quality and marketability of grape fruit of Qızıl Uzum cultivar. [ABSTRACT FROM AUTHOR]

The study investigated the antioxidant effects of roasted Cudrania tricuspidata (C. tricuspidata) fruits by comparing them with unroasted C. tricuspidata fruits. The results showed that the roasted C. tricuspidata fruits (150 °C, 120 min) exhibited significantly higher antioxidant activity, especially in terms of anti-inflammatory effects, than the unroasted fruits. Interestingly, there is a high correlation between the color of the roasted fruit and the antioxidant activity. Heating disrupts cells and deactivates endogenous oxidative enzymes, leading to an increase in flavonoid content. Moreover, heat treatment may also interfere with plant metabolism, thereby influencing flavonoid content. Moreover, an HPLC analysis of roasted fruits in our study showed that the increase in antioxidant activity was attributed to the increase in flavan-3-ols and phenolic acids in the roasted C. tricuspidata fruits. To the best of our knowledge, this is the first time the antioxidant activity and anti-inflammation of roasted C. tricuspidata fruits was studied. The study concluded that roasted C. tricuspidata fruits could be a valuable natural source of antioxidants for various food and medicinal applications. [ABSTRACT FROM AUTHOR]

Besides of bitter acids, hop polyphenols can influence the sensory properties of beer. While the concentration of bitter acids is tightly monitored by the hop industry, comprehensive datasets concerning the polyphenols do not exist yet. To quantitate the hop phenolic compounds, LC-MS/MS analysis was applied to various hop varieties from different growing regions for the harvest year 2021 (> 400 samples). The list of compounds tested includes multifidol glucosides, flavonol glycosides and their aglycones, flavan-3-ols, procyanidins, and phenolic acids. The multifidol glucosides (co- and ad-multifidol glucoside) are typical to hops as intermediates in the biosynthesis of bitter acids. The detected concentrations for co-multifidol glucoside are between 8-200 mg/100 g depending on hop variety. Consistently low amounts (< 5 mg/100 g) were found for quercetin, kaempferol or myricetin as flavonol aglycones in comparison to their glycosides quercetin and kaempferol glucoside or quercetin and kaempferol rutinoside (up to 100 mg/100 g). Characteristics for single hop cultivars were observed for the procyanidins B1, B2 and B3, and for the flavan-3-ols catechin and epicatechin. [ABSTRACT FROM AUTHOR]

The phenolic profile of wines is often used to evaluate their quality and authenticity. The phenolic composition of twenty-five commercial wines produced in different Croatian regions from eight red and nine white grape varieties was studied. A total of twenty-four polyphenols were analyzed using HPLC-DAD and classified into five groups based on their structure: phenolic acids, flavan-3-ols, anthocyanins, flavonoids, and stilbenes. The red wines contained higher concentrations of phenolic constituents than the white wines, of which gallic acid (11.8–90.3 mg/L), procyanidin B1 (13.7–63.8 mg/L), and catechin (10.5–34.5 mg/L) were the most abundant. In contrast to the white wines, great variability was observed in the red wines, with the autochthonous Plavac Mali and Babić showing the most specific phenolic profiles. The most representative phenolic components in the studied Croatian wines showed strong antioxidant activity. Gallic acid proved to be the most effective DPPH (IC50 = 0.33 µg/mL) and NO scavenger (IC50 = 12.36 µg/mL), while myricetin was the most potent inhibitor of lipid peroxidation (IC50 = 1.68 µg/mL). Our research has contributed to the characterization and varietal differentiation of Croatian wines, highlighting those rich in certain polyphenols as potential nutraceuticals. [ABSTRACT FROM AUTHOR]

More than ten thousand apple cultivars with high variability in the quality traits and year-round availability place apples at the forefront of consumed fruits. Yet consumers and producers alike are still looking for new apple cultivars with specific quality attributes such as plant resistance to biotic and abiotic stresses as well as a high health-promoting potential. The model plants were three cultivars: a new 'Chopin' and an old 'Granny Smith', scab resistant cultivars with green peel, and a red-skinned cultivar 'Gala Schniga'. Apple peel and flesh were analyzed separately during two growing seasons: 2016 and 2017. The total ascorbate and phenolics as well as individual phenolic compounds, such as (+)-catechin, (−)-epicatechin, chlorogenic acid, phloridzin, and rutin concentrations, proved to be highly tissue-type and cultivar dependent. The apple of the 'Chopin' and 'Granny Smith' cultivars expressed much lower skin-to-flesh antioxidant potential differences as compared to 'Gala Schniga'. The lowest differences between tissue types were observed in the case of chlorogenic acid and flavan-3-ols, followed by total phenolics and ascorbate concentrations. Except for phloridzin, 'Gala Schniga' exhibited the highest differences in global and individual phenolic compound concentrations as well as total antioxidant capacity between the apple peel and flesh. 'Chopin' was definitely distinguished by the highest concentration of ascorbate in both the peel and the flesh and expressed a higher concentration of flavanols, especially compared to 'Granny Smith'. In contrast to 'Gala Schniga', 'Chopin' was richer in chlorogenic acid, (+)-catechin, and (−)-epicatechin in the flesh. The total antioxidant capacity of the green-peel apple cultivars was similar to that of the red-peel one. A narrower range of differences between the concentration of antioxidants in apple peel and flesh could mean better health-promoting properties and might be related to a greater resistance to environmental stress factors. [ABSTRACT FROM AUTHOR]

Flavan-3-ols are important dietary polyphenol, their bioavailability are not only limited to the parent compound, but also the metabolites after the intestinal microbial metabolism in vivo. Aimed to identify the vivo metabolism and the contribution of metabolites to bioavailability, the quantitative analysis methods of dietary flavan-3-ols and their metabolites were researched. According to the difference response value of the product ions of each compound, the appropriate concentration in the mixed standard was determined, and the quantitative analysis method of ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry (UHPLC-QQQ-MS) was established. All compounds had good resolution and appropriate response values within analysis time of 15 min. The method validation results showed that most of the quantitative compounds had good linearity. Urine, feces and plasma were used as samples to investigate the intra-day and the inter-day precision of the method. The RSD value of the method was below 15%, the matrix effect was within ±20%, and the recovery was mainly between 70% and 120%. The method is fast, sensitive, accurate and stable, whicih can be used as a method for targeted quantitative research of flavan-3-ol compounds in vivo.

The contents of total phenolics, anthocyanins, flavan-3-ols, and the fruit antioxidant activity of 9 pomegranate varieties ('Zumnarija', 'Bejnarija', 'Valandovska kisela', 'Valandovska kiselo-slatka', 'Hidjas', 'Kisela', 'Karamustafa', 'Lifanka', and 'Ropkavec') were examined. Autochthonous pomegranate varieties contained 4354.4-6480.9 mg/kg FW total phenols, 160-698.2 mg/kg FW anthocyanins, 96.9-157.2 mg/kg FW flavan-3-ols, and high antioxidant activity of fruits (71.2-92.5% inhibition). The 'Valandovska kisela' variety had the highest content of total phenolics (6480.87 mg/kg FW), flavan-3-ols (157.190 mg/kg FW) and higher fruit antioxidant activity (92.5% inhibition) compared to the standard 'Karamustafa' variety and the other autochthonous varieties. The 'Hidjas' variety had the highest content of anthocyanins (698.20 mg/kg FW). A positive correlation (0.9815) was found between the content of total phenolics and the fruit antioxidant activity. A moderate positive, insignificant correlation was also found between the content of flavan-3-ols and anthocyanins.

Phenolic compounds of 25 newly introduced strawberry cultivars were profiled using spectrophotometry, electron paramagnetic resonance (EPR) spectroscopy, and high-performance liquid chromatography-mass spectrometry. Total phenolic and anthocyanin content (TPC and TACY, respectively), as well as vitamin C, and concentrations of individual phenolic compounds in fruits were evaluated to identify the most promising cultivars according to their phenolic profile. The highest values of TPC, TACY, and vitamin C were recorded in 'Premy' (1.53 mg eq GA g−1 FW), 'Sandra' (30.60 mg eq Pg-3-g 100 g−1 FW), and 'Laetitia' (56.32 mg 100 g−1 FW), respectively. The DPPH and •OH radicals scavenging activity of fruit methanolic extracts was estimated using EPR spectroscopy. All cultivars are almost uniformly effective in the scavenging of •OH radical, while 'Tea', 'Premy', and 'Joly' were marked as highly potent cultivars (over 70%) in terms of DPPH-antiradical activity. Specific peroxidase activities were the highest in 'Garda', 'Federica', and 'Rumba' (0.11, 0.08, and 0.06 U mg−1 prot, respectively). 'Laetitia', 'Joly', 'Arianna', 'Tea', and 'Mila' cultivars were distinguished from others as the richest concerning almost all flavonoids and phenolic acids, including some other parameters of bioactivity. These cultivars could be recommended to consumers as functional fruit foods. [ABSTRACT FROM AUTHOR]

Nowadays, non-alcoholic (NAB) and low-alcoholic beers (LAB) still significantly suffer from staling defects when fresh, partially due to absence of ethanol as antioxidant. In the current work, the fate of flavan-3-ols (monomers, dimers, and trimers) and bitter compounds (isohumulones, humulinones, etc.) of 11 commercial NABLABs available on the Belgian market was monitored through one year of aging at 20 °C in the dark. Fresh NABLABs contained variable flavan-3-ols and bitter compounds levels (between 3.0–10.0 mg/L and 8.0–39.0 mg/L, respectively), depending on different technological processes used. Chill haze and color were also investigated as potential oxidation markers of fresh and aged beers. Surprisingly, contrary to conventional beers, the oligomers' concentration (dimer and trimer procyanidins) exhibited a strong correlation (R2 = 0.95) with chill haze before aging, suggesting prematured oxidation of the samples. After a year of storage, significant degradation occurred as for regular dry hopped beers (process very sensitive to oxidation), only 27% remaining for flavan-3-ol dimers and an average 16% for trans-isohumulones. Oxidation risk appears here as the main weakness of NABLABs, which could be probably improved by spiking very efficient antioxidants. [ABSTRACT FROM AUTHOR]

Tea leaves are rich in diverse metabolites with medicinal importance. The quality of made tea is largely depended on the qualitative and quantitative attributes of key metabolites. The aim of the present study was to quantify flavan-3-ols and caffeine of exotic tea germplam and explore the medicinal properties. Fresh leaf flavan-3-ols; catechin, epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC) and epigallocatechin gallate (EGCg), caffeine and gallic acid of 131 accessions (87 exotic and 44 improved cultivars) were performed by High Performance Liquid Chromatography. Variations in metabolites among cultivars as well as between seasons were determined. Among the flavan-3-ols, EGCg was the most abundant followed by EGC, ECg and EC. Hierarchical clustering of 131 accessions based on metabolite diversity resulted two major clusters. Indian introductions clustered with well-known high quality cultivars indicating the potential utilization of high quality black tea production. Exotic accessions with low caffeine contents (< 20 mg g−1) were grouped separate cluster indicating the promising genetic resources for the development of low caffeine tea. Present study revealed that selected exotic tea accessions rich in bioactive compounds such as catechins and caffeine content could be utilized in producing speciality teas with enhanced quality and medicinal properties.

While the Saaz aromatic variety remains classified as a total-flavanoid-rich cultivar, no inverse correlation was found between total flavanoids and the α-acid content when the dual-purpose varieties Citra, CTZ, Amarillo, Eureka!, Mandarina Bavaria, Mosaic, Polaris, and Sabro were considered. The levels of hop flavan-3-ol monomers, dimers, and trimers (quantitated by HPLC-MS/MS) appeared strongly influenced by variety and harvest year. On the other hand, the catechin/epicatechin ratio (and B3/B2 ratio) proved stable within the same variety through two successive harvest years. Among the nine herein-investigated varieties, Citra and Saaz displayed notable catechin/epicatechin ratios (>3.7 compared to

Avocado peel and seed are the main by-products of avocado processing and are considered as promising sources of phenolic compounds with biological activities. Thus, this research focuses on the establishment, for the first time, of ultrasound-assisted extraction of flavan-3-ols with high antioxidant activity from avocado peel and seed using a sonotrode. Indeed, 2 Box–Behnken designs were performed for 15 experiments, with each design having three independent factors (ratio ethanol/water (v/v), time (min) and amplitude (%)). In both models, the responses included total procyanidins (flavan-3-ols) measured via HPLC-FLD and antioxidant activity measured via DPPH, ABTS and FRAP. The results showed that applying the sonotrode extraction method could increase flavan-3-ols recovery by 54% and antioxidant activity by 62–76% compared to ultrasound bath technology. Therefore, this technology was demonstrated to be a non-thermal, low time-consuming and scalable method that allowed the recovery of flavan-3-ols from avocado by-products that could be used as functional ingredients.

[Display omitted] • Substitution patterns significantly affect the copigmentation ability of monomeric flavan-3-ols. • Hydroxy group addition to the B ring slightly enhanced copigmentation. • Esterification of the C3 hydroxyl group with gallic acid markedly enhanced copigmentation. • Substitution effects are closely linked to stereoisomeric configurations. Monomeric flavan-3-ols are important copigments in red wines, due to their superior copigmentation ability and high concentration. In this work, a systematic study was conducted on the copigmentation effects of eight common monomeric flavan-3-ols with malvidin-3- O -glucoside, using experimental and theoretical methods. The results revealed that the addition of a hydroxy group to the B ring and the attachment of a galloyl group at the 3- O position of monomeric flavan-3-ols both contributed to enhance copigmentation, with the latter exerting a more pronounced effect. Regarding stereoisomerism, it was observed that the cis -configuration of the B ring and 3- O -hydroxy group favored copigmentation. However, the cis -configuration of the B ring and 3- O -galloyl group was disadvantageous due to steric hindrance, in contrast to when these moieties occupied opposing sides (i.e., the 2,3- trans configuration). These results highlight the crucial role played by both substitution patterns and conformational arrangements in determining the copigmentation ability of monomeric flavan-3-ols. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flavan-3-ol-rich apple juices were made with the emerging spiral filter technology. • Novel insights into flavan-3-ol reactions with sugars and other carbonyl compounds. • Ascorbic acid had a protective and destabilizing effect on flavan-3-ols. • Storage of apple juice as concentrates accelerated flavan-3-ol degradation. • New UHPLC- and HILIC-ESI(−)-QTOF-HR-MS/MS data on flavan-3-ol degradation products. Potentially health-promoting concentrations of flavan-3-ols were previously shown to be retained in apple juices produced with the emerging spiral filter press. Due to the novelty of this technology, the factors governing the stability of flavan-3-ol-rich apple juices have only scarcely been studied. Therefore, we produced flavan-3-ol-rich apple juices and concentrates (16, 40, 70 °Brix) supplemented with ascorbic acid (0.0, 0.2, 1.0 g/L) according to common practice. Flavan-3-ols (DP1-7) and twelve flavan-3-ol reaction products were comprehensively characterized and monitored during storage for 16 weeks at 20 and 37 °C, employing RP-UHPLC- and HILIC-DAD-ESI(−)-QTOF-HR-MS/MS. Flavan-3-ol degradation followed a second-order reaction kinetic, being up to 3.5-times faster in concentrates (70 °Brix) than in single strength juices (16 °Brix). Furthermore, they diminished substantially faster compared to other phenolic compounds. For instance, after 16-weeks at 20 °C, the maximum loss of flavan-3-ols (−70 %) was greater than those of hydroxycinnamic acids (−18 %) and dihydrochalcones (−12 %). We observed that flavan-3-ols formed adducts with sugars and other carbonyls, such as 5-(hydroxymethyl)furfural and the ascorbic acid-derived L-xylosone. Increased degradation rates correlated particularly with increased furan aldehyde levels as found in concentrates stored at elevated temperatures. These insights could be used for optimizing production, distribution, and storage of flavan-3-ol-rich apple juices and other foods and beverages. [ABSTRACT FROM AUTHOR]

Flavan-3-ols are monomers of Proanthocyanidins (PAs), which are important polyphenolic compounds in grapes. Previous studies had shown that VvMYBPA2 was closely related to grape flavan-3-ol monomers biosynthesis, but its regulatory network is still unclear. Here, we found that the contents of (+)-catechin and (−)-epicatechin, the enzyme activities of anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR) and the expression of VvANR and VvLAR1 were increased in the VvMYBPA2 overexpression grape leaves compared to the control. It was proved that VvMYBPA2 protein interacted with VvWDR1 and VvWDR1 protein interacted with VvMYC2 by yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC). The promoters of VvANR and VvLAR1 were bound by VvMYBPA2 using yeast one-hybrid (Y1H) assay. These results suggested that VvMYBPA2 could form a trimeric complex with VvWDR1 and VvMYC2 and jointly regulated the expression of flavan-3-ol monomers related genes VvANR and VvLAR1, thereby affecting the enzyme activities of ANR and LAR and ultimately regulating the contents of flavan-3-ols. [ABSTRACT FROM AUTHOR]

Seed extracts are becoming more important due to their beneficial biological activities. The main constituents of seed extracts are flavan-3-ols, compounds important in winemaking. The coastal region in Croatia is rich in native grapevine varieties, which are used in wine production. The aim of the research was to analyze the flavan-3-ol profiles of 20 native varieties, and to evaluate the potential use of grape seeds as a source of flavan-3-ols. The flavan-3-ols from seeds were analyzed by HPLC. The predicted yield of flavan-3-ols was calculated using the analyzed profiles. In total, eight compounds were identified, with the most abundant compounds being catechin, epicatechin, and procyanidin B2. In general, the red grape varieties had higher content of flavan-3-ols than the white varieties, which was confirmed by PCA. The coastal region could potentially yield up to 73.97 kg/ha of flavan-3-ols, depending on the variety. The results show the diversity of flavan-3-ol profiles among Croatian varieties and their potential usage as a source of valuable nutraceuticals. [ABSTRACT FROM AUTHOR]

Summary: Salicylic acid (SA) and jasmonic acid (JA) often play distinct roles in plant defence against pathogens. Research from Arabidopsis thaliana has established that SA‐ and JA‐mediated defences are more effective against biotrophs and necrotrophs, respectively. These two hormones often interact antagonistically in response to particular attackers, with the induction of one leading to suppression of the other. Here, we report a contrasting pattern in the woody perennial Populus: positive SA–JA interplay.Using genetically engineered high SA lines of black poplar and wild‐type lines after exogenous hormone application, we quantified SA and JA metabolites, signalling gene transcripts, antifungal flavonoids and resistance to rust (Melampsora larici‐populina).Salicylic acid and JA metabolites were induced concurrently upon rust infection in poplar genotypes with varying resistance levels. Analysis of SA‐hyperaccumulating transgenic poplar lines showed increased jasmonate levels, elevated flavonoid content and enhanced rust resistance, but no discernible reduction in growth. Exogenous application of either SA or JA triggered the accumulation of the other hormone. Expression of pathogenesis‐related (PR) genes, frequently used as markers for SA signalling, was not correlated with SA content, but rather activated in proportion to pathogen infection.We conclude that SA and JA pathways interact positively in poplar resulting in the accumulation of flavonoid phytoalexins. [ABSTRACT FROM AUTHOR]

Renal hypoxia and its associated oxidative stress is a common pathway for the development of kidney diseases, and using dietary antioxidants such as flavan-3-ols to prevent kidney failure has received much attention. This study investigates the molecular mechanism by which flavan-3-ols prevent hypoxia-induced cell death in renal tubular epithelial cells. Human kidney proximal tubular cells (HKC-8) were exposed to hypoxia (1% O2) in the presence of flavan-3-ols (catechin, epicatechin, procyanidin B1, and procyanidin B2). Cell death was examined using flow cytometric analysis. Gene expression was determined using a PCR array and Western blotting, and its network and functions were investigated using STRING databases. Here, we show that the cytoprotective activity of catechin was the highest among these flavan-3-ols against hypoxia-induced cell death in cultured HKC-8 cells. Exposure of HKC-8 cells to hypoxia induced oxidative stress leading to up-regulation of DUOX2, NOX4, CYBB and PTGS2 and down-regulation of TXNRD1 and HSP90AA1. Treatment with catechin or other flavan-3-ols prevented the down-regulation of TXNRD1 expression in hypoxic HKC-8 cells. Overexpression of TXNRD1 prevented hypoxia-induced cell death, and inactivation of TXNRD1 with TRi-1, a specific TXNRD1 inhibitor, reduced the catechin cytoprotection against hypoxia-induced HKC-8 cell death. In conclusion, flavan-3-ols prevent hypoxia-induced cell death in human proximal tubular epithelial cells, which might be mediated by their maintenance of TXNRD1 expression, suggesting that enhancing TXNRD1 expression or activity may become a novel therapeutic strategy to prevent hypoxia-induced kidney damage. [ABSTRACT FROM AUTHOR]

Since December 2019, the deadly novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the current COVID-19 pandemic. To date, vaccines are available in the developed countries to prevent the infection of this virus; however, medicines are necessary to help control COVID-19. Human coronavirus 229E (HCoV-229E) causes the common cold. The main protease (Mpro) is an essential enzyme required for the multiplication of these two viruses in the host cells, and thus is an appropriate candidate to screen potential medicinal compounds. Flavonols and dihydroflavonols are two groups of plant flavonoids. In this study, we report docking simulation with two Mpro enzymes and five flavonols and three dihydroflavonols, in vitro inhibition of the SARS-CoV-2 Mpro, and in vitro inhibition of the HCoV 229E replication. The docking simulation results predicted that (+)-dihydrokaempferol, (+)- dihydroquercetin, (+)-dihydromyricetin, kaempferol, quercetin, myricentin, isoquercitrin, and rutin could bind to at least two subsites (S1, S1', S2, and S4) in the binding pocket and inhibit the activity of SARS-CoV-2 Mpro. Their affinity scores ranged from −8.8 to −7.4 (kcal/mol). Likewise, these compounds were predicted to bind and inhibit the HCoV-229E Mpro activity with affinity scores ranging from −7.1 to −7.8 (kcal/mol). In vitro inhibition assays showed that seven available compounds effectively inhibited the SARS-CoV-2 Mpro activity and their IC 50 values ranged from 0.125 to 12.9 μM. Five compounds inhibited the replication of HCoV-229E in Huh-7 cells. These findings indicate that these antioxidative flavonols and dihydroflavonols are promising candidates for curbing the two viruses. • Ligand-receptor docking modeling shows flavonols and dihydroflavonols could bind to main protease of SARS-Cov-2. • Flavonols and dihydroflavonols could inhibit the SARS-Cov-2 main protease activities in vitro. • Flavonols and dihydroflavonols could inhibit the hCoV-229E replication in Huh-7 cells. [ABSTRACT FROM AUTHOR]

Terpenes and phenolics are important constitutive and inducible conifer defenses against bark beetles and their associated fungi. In this study, the inducible defenses of mature Norway spruce (Picea abies) trees with different histories of attack by the spruce bark beetle, Ips typographus were tested by inoculation with the I. typographus -associated fungus Endoconidiophora polonica. We compared trees that had been under previous attack with those under current attack and those that had no record of attack. After fungal inoculation, the concentrations of mono-, sesqui-, and diterpenes in bark increased 3- to 9-fold. For the phenolics, the flavan-3-ols, catechin, and gallocatechin, increased significantly by 2- and 5-fold, respectively, while other flavonoids and stilbenes did not. The magnitudes of these inductions were not influenced by prior bark beetle attack history for all the major compounds and compound classes measured. Before fungal inoculation, the total amounts of monoterpenes, diterpenes, and phenolics (constitutive defenses) were greater in trees that had been previously attacked compared to those under current attack, possibly a result of previous induction. The transcript levels of many genes involved in terpene formation (isoprenyl diphosphate synthases and terpene synthases) and phenolic formation (chalcone synthases) were significantly enhanced by fungal inoculation suggesting de novo biosynthesis. Similar inductions were found for the enzymatic activity of isoprenyl diphosphate synthases and the concentration of their prenyl diphosphate products after fungal inoculation. Quantification of defense hormones revealed a significant induction of the jasmonate pathway, but not the salicylic acid pathway after fungal inoculation. Our data highlight the coordinated induction of terpenes and phenolics in spruce upon infection by E. polonica , a fungal associate of the bark beetle I. typographus , but provide no evidence for the priming of these defense responses by prior beetle attack. [ABSTRACT FROM AUTHOR]

Purpose: Extensive inter-individual variability exists in the production of flavan-3-ol metabolites. Preliminary metabolic phenotypes (metabotypes) have been defined, but there is no consensus on the existence of metabotypes associated with the catabolism of catechins and proanthocyanidins. This study aims at elucidating the presence of different metabotypes in the urinary excretion of main flavan-3-ol colonic metabolites after consumption of cranberry products and at assessing the impact of the statistical technique used for metabotyping. Methods: Data on urinary concentrations of phenyl-γ-valerolactones and 3-(hydroxyphenyl)propanoic acid derivatives from two human interventions has been used. Different multivariate statistics, principal component analysis (PCA), cluster analysis, and partial least square-discriminant analysis (PLS-DA), have been considered. Results: Data pre-treatment plays a major role on resulting PCA models. Cluster analysis based on k-means and a final consensus algorithm lead to quantitative-based models, while the expectation–maximization algorithm and clustering according to principal component scores yield metabotypes characterized by quali-quantitative differences in the excretion of colonic metabolites. PLS-DA, together with univariate analyses, has served to validate the urinary metabotypes in the production of flavan-3-ol metabolites and to confirm the robustness of the methodological approach. Conclusions: This work proposes a methodological workflow for metabotype definition and highlights the importance of data pre-treatment and clustering methods on the final outcomes for a given dataset. It represents an additional step toward the understanding of the inter-individual variability in flavan-3-ol metabolism. Trial registration: The acute study was registered at clinicaltrials.gov as NCT02517775, August 7, 2015; the chronic study was registered at clinicaltrials.gov as NCT02764749, May 6, 2016. [ABSTRACT FROM AUTHOR]