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Background and Aims: Several studies propose that (-)-epicatechin, a flavonol present in high concentration in the cocoa, has cardioprotective effects. This study aimed to evaluate the impact of (-)-epicatechin on the development of dilated cardiomyopathy in a δ sarcoglycan null mouse model.Methods and Results: δ Sarcoglycan null mice were treated for 15 days with (-)-epicatechin. Histological and morphometric analysis of the hearts treated mutant mice showed significant reduction of the vasoconstrictions in the coronary arteries as well as fewer areas with fibrosis and a reduction in the loss of the ventricular wall. On the contrary, it was observed a thickening of this region. By Western blot analysis, it was shown, and increment in the phosphorylation level of eNOS and PI3K/AKT/mTOR/p70S6K proteins in the heart of the (-)-epicatechin treated animals. On the other hand, we observed a significantly decreased level of the atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) heart failure markers.Conclusion: All the results indicate that (-)-epicatechin has the potential to prevent the development of dilated cardiomyopathy of genetic origin and encourages the use of this flavonol as a pharmacological therapy for dilated cardiomyopathy and heart failure diseases. [ABSTRACT FROM AUTHOR]

The solubility of a bioactive compound is an important phenomenon in chemical and food processing industries. Many pharmaceutical and food industries are focused on solubilization and formulation development of bioactive compounds. The solubility of the (−)-epicatechin in 75% ethanol, methanol, acetone, and water was investigated as a function of temperature (298.15 to 338.15 K) at 0.1 MPa atmospheric pressure and correlated with calculated solubility. The experimental solubility of (−)-epicatechin was also evaluated based on the thermodynamic principles of the modified Apelblat model. The experimental solubility of (−)-epicatechin in pure solvents increased with increasing temperature from 298.15 to 338.15 K. The highest (0.2 ± 0.1 × 10 −2 ) and lowest (0.7 ± 0.2 × 10 −4 ) solubilities of (−)-epicatechin were observed in pure water at 338.15 and 298.15 K, respectively. The experimental solubilities were correlated with isothermal models (Apelblat and ideal equations) at each studied temperature, and a modified Apelblat model was used to evaluate experimental solubility of (−)-epicatechin based on the thermodynamic principles. The results showed good root-mean-square deviations (RMSD) and average relative deviations (ARD) as 0.1 to 0.9 and − 0.6 to 0.02, respectively, for the Apelblat model. For the ideal equation, RMSD and ARD were obtained as 0.1 to 0.9 and − 0.01 to −0.3, respectively. Changes in enthalpies (∆H°) and entropies (∆S°) for (−)-epicatechin dissolution occurred in the ranges of −64 ± 4 to 201 ± 4 kJ mol −1 and -216 ± 14 to 595 ± 2 J mol −1  K −1 , respectively. These thermodynamic analyses indicated that the process was endothermic, entropy-driven, and favorable at studied temperatures in pure solvents. The results suggested that the (−)-epicatechin could solubilize in the solvents, especially in 75% ethanol and acetone, and therefore useful to pharmaceutical industries for bioactive product formulation. [ABSTRACT FROM AUTHOR]

Recent studies have suggested that certain (−)-epicatechin-containing foods have a blood pressure-lowering capacity. The mechanisms underlying (−)-epicatechin action may help prevent oxidative damage and endothelial dysfunction, which have both been associated with hypertension and certain brain disorders. Moreover, (−)-epicatechin has been shown to modify metabolic profile, blood's rheological properties, and to cross the blood-brain barrier. Thus, (−)-epicatechin causes multiple actions that may provide unique synergy beneficial for cardiovascular and neuropsychological health. This review summarises the current knowledge on the biological actions of (−)-epicatechin, related to cardiovascular and brain functions, which may play a remarkable role in human health and longevity. [ABSTRACT FROM AUTHOR]

To potentially identify proteins that interact (i.e. bind) and may contribute to mediate (−)-epicatechin (Epi) responses in endothelial cells we implemented the following strategy: 1) synthesis of novel Epi derivatives amenable to affinity column use, 2) in silico molecular docking studies of the novel derivatives on G protein-coupled estrogen receptor (GPER), 3) biological assessment of the derivatives on NO production, 4) implementation of an immobilized Epi derivative affinity column and, 5) affinity column based isolation of Epi interacting proteins from endothelial cell protein extracts. For these purposes, the Epi phenol and C3 hydroxyl groups were chemically modified with propargyl or mesyl groups. Docking studies of the novel Epi derivatives on GPER conformers at 14 ns and 70 ns demostrated favorable thermodynamic interactions reaching the binding site. Cultures of bovine coronary artery endothelial cells (BCAEC) treated with Epi derivatives stimulated NO production via Ser1179 phosphorylation of eNOS, effects that were attenuated by the use of the GPER blocker, G15. Epi derivative affinity columns yielded multiple proteins from BCAEC. Proteins were electrophoretically separated and inmmunoblotting analysis revealed GPER as an Epi derivative binding protein. Altogether, these results validate the proposed strategy to potentially isolate and identify novel Epi receptors that may account for its biological activity. [ABSTRACT FROM AUTHOR]

(−)-Epicatechin is a brain-permeable, natural product found at high concentrations in green tea and cocoa. Our previous research has shown that (−)-epicatechin treatment reduces hemorrhagic stroke injury via nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway in vivo. However, the mechanism of action of this compound in modulation of oxidant stress and in protection against hemoglobin-induced astrocyte injury is unclear. Therefore, we explored the cellular and molecular mechanisms that underlie these protective effects in vitro. Mouse primary astrocytes isolated from wild-type mice and Nrf2 knockout (KO) mice were preconditioned with hemoglobin to simulate intracerebral hemorrhage (ICH) in vitro. Effects of (−)-epicatechin were measured by Western blotting, immunostaining, MTT assay, and reactive oxidant stress (ROS) assay. (−)-Epicatechin increased Nrf2 nuclear accumulation and cytoplasmic levels of superoxide dismutase 1 (SOD1) in wild-type astrocytes but did not increase SOD1 expression in Nrf2 knockout (KO) astrocytes. Furthermore, (−)-epicatechin treatment did not alter heme oxygenase 1 (HO1) expression in wild-type astrocytes after hemoglobin exposure, but it did decrease HO1 expression in similarly treated Nrf2 KO astrocytes. In both wild-type and Nrf2 KO astrocytes, (−)-epicatechin suppressed phosphorylated JNK and nuclear expression of JNK, c-jun, and c-fos, indicating that inhibition of activator protein-1 (AP-1) activity by (−)-epicatechin is Nrf2-independent. These novel findings indicate that (−)-epicatechin protects astrocytes against hemoglobin toxicity through upregulation of Nrf2 and inhibition of AP-1 activity. These cellular and molecular effects may partially explain the cerebroprotection as we previously observed for (−)-epicatechin in animal models of ICH. [ABSTRACT FROM AUTHOR]

(−)-Epicatechin (EC) exhibits antioxidant effects and strengthens skeletal muscle growth and differentiation in mammals. However, there are no reports about the effects of EC in fish. This study evaluated the effects of EC on muscle antioxidant capacity, myofiber development, texture characteristics, and histomorphology were also investigated through feeding trial. 300 fish (16.27 ± 0.24 g) were fed four diets with different levels of EC (0, 100, 500, and 1000 mg/kg) for 60 days. The result showed that 1000 mg/kg EC supplementation enhanced antioxidant capacity and protein content in the muscle. Meanwhile, higher expression levels of proliferating cell nuclear antigen (pcna), myogenic differentiation antigen (myod), myogenin , myosin myosin heavy chain (myhc), and myosin light chain (mylc) were detected in the muscle of EC treatment, while the myostatin (mstnb) mRNA level was decreased in the EC 1000 group, the similar trends were observed in the protein expression levels of MyoD, Myogenin, MyLc (P < 0.05). Muscle hardness and pH value were increased significantly in EC 500 and 1000 groups (P < 0.05). Additionally, myofiber density, small-sized fiber percentage, and expression of genes related to AMP-activated protein kinase (AMPK) signaling pathway was promoted in the EC groups. These results indicated that dietary EC improved fillet quality and promoted myofiber development in Yellow River carp, which might be related to AMPK pathway. [Display omitted] • Dietary (−)-Epicatechin (EC) could enhance muscle antioxidant capacity. • Dietary EC change the myofibers diameter and density of Yellow River carp. • Dietary EC could improve the fillet quality of Yellow River carp. • Dietary EC affected muscle development probably due to AMPK/SIRT1/PGC-1α pathway. [ABSTRACT FROM AUTHOR]

Phenolic composition of litchi (Litchi chinensis Sonn.) pulp from three cultivars was tentatively characterized and quantified by HPLC–MS. Pulp from hemaoli, a wild litchi cultivar, showed the highest content of total phenolics, flavonoids and procyanidins, the latter accounting for the majority of phenolic compounds identified. In hemaoli, (−)-epicatechin was the predominant compound, whereas flavone glycosides accounted for the majority of the phenolic compounds identified in Feizixiao and Lanzhu cultivars, with quercetin rhammosyl-rutinoside being predominant. Hemaoli pulp caused the highest enhancement of glucose consumption rate in HepG2 cells, followed by Feizixiao pulp. This bioactivity was significantly correlated with antioxidant capacity, and total content of phenolics, flavonoids, and procyanidins of different cultivars. (−)-Epicatechin, but not quercetin rhammosyl-rutinoside, also resulted in a significant rise in glucose consumption activity. These results showed that litchi cultivars with high (−)-epicatechin content or high procyanidin content may have great potential as hypoglycaemic foods.

Background: Exaggerated Toll-like receptor (TLR)-mediated immune and inflammatory responses play a role in inflammatory bowel diseases. This report deals with the ability of a mixture of oxysterols widely present in cholesterol-rich foods to induce in vitro intestinal inflammation through TLR up-regulation. The anti-inflammatory action of four cocoa bean shell (CBS) extracts with different polyphenol content, was tested. Methods: Differentiated intestinal CaCo-2 cells were treated with a dietary oxysterol mixture (Oxy-mix) (60 µM). The expression and activation of TLR2 and TLR4, as well as the production of their downstream signaling effectors IL-8, IFNβ and TNFα were analyzed in the presence or absence of TLR antibodies. Honduras CBS extracts were characterized for their polyphenol contents; their anti-inflammatory action was analyzed in CaCo-2 cells treated with Oxy-mix. Results: Oxysterol-dependent TLR-2 and TLR4 over-expression and activation together with cytokine induction were abolished by blocking TLRs with specific antibodies. Polyphenol-rich CBS extracts consisting of high quantities of (−)-epicatechin and tannins also prevented TLR induction. Conclusions: TLR2 and TLR4 mainly contribute to inducing oxysterol-dependent intestinal inflammation. The fractionation method of CBS allowed the recovery of fractions rich in (−)-epicatechin and tannins able to counteract oxysterol-induced inflammation, thus highlighting the beneficial biological potential of specific CBS extracts.

Hydrogen–Deuterium exchange kinetics of β -lactoglobulin and β -lactoglobulin (−)-epicatechin solutions has been investigated through the analysis of the amide I absorption band at 1650 cm −1 in the FTIR spectrum. H–D substitution in NH amides and residues of the protein results in a slight red-shift and in intensity changes of the amide I components: either these effects have been inspected in the framework of the Principal Components Analysis methods. The present analysis allowed to unveil three H–D kinetics at the timescale of the oligomeric fluctuations of the protein. A fast mechanism (lifetime from 5 to 10 min) can be ascribed to the dynamics of protein oligomers and aggregates at the scale of the quaternary structure variations, and it is not observed in the complexes β -lactoglobulin (−)-epicatechin. The other slowest kinetics, whose lifetimes are in the range 1–10 h, are here associated to dynamics of high-molecular weight complexes that hamper the proton exchange. The role of (−)-epicatechin as an enhancer of the formation of stable high-molecular weight aggregates from β -lactoglobulin is also discussed by comparison of the lifetimes at different protein concentrations. [ABSTRACT FROM AUTHOR]

(−)-Epicatechin (EPI) has beneficial effects on the cardiovascular disease. The human ether-a-go-go-related gene (HERG) potassium channel is crucial for repolarization of cardiac action potential. Dysfunction of the HERG channel can cause long QT syndrome type 2 (LQT2). Arsenic trioxide (As2O3) has shown efficacy in the treatment of acute promyelocytic leukemia. However, As2O3 can induce the deficiency of HERG channel and cause LQT2. In this study, we examined whether EPI could rescue the As2O3-induced HERG channel deficiency. We found that 3 μM EPI obviously increased protein expression and current of HERG channel. EPI was able to recover the protein expression and current of HERG channel disrupted by As2O3. EPI was able to increase the expression of SP1 protein and recover the expression of SP1 protein disrupted by As2O3. In addition, EPI significantly shortened action potential duration prolonged by As2O3. Our data suggest that EPI rescues As2O3-induced HERG channel deficiency through upregulating SP1 expression. [ABSTRACT FROM AUTHOR]

(−)-Epicatechin (EC), an optical antipode of (+)-catechin (C), possesses many potential significant health benefits. However, the in vivo metabolic pathway of EC has not been clarified yet. In this study, an efficient strategy based on ultra-high performance liquid chromatography coupled with a linear ion trap-Orbitrap mass spectrometer was developed to profile and characterize EC metabolites in rat urine, faeces, plasma, and various tissues. Meanwhile, post-acquisition data-mining methods including high-resolution extracted ion chromatogram (HREIC), multiple mass defect filters (MMDFs), and diagnostic product ions (DPIs) were utilized to screen and identify EC metabolites from HR-ESI-MS1 to ESI-MS n stage. Finally, a total of 67 metabolites (including parent drug) were tentatively identified based on standard substances, chromatographic retention times, accurate mass measurement, and relevant drug biotransformation knowledge. The results demonstrated that EC underwent multiple in vivo metabolic reactions including methylation, dehydration, hydrogenation, glucosylation, sulfonation, glucuronidation, ring-cleavage, and their composite reactions. Among them, methylation, dehydration, glucosylation, and their composite reactions were observed only occurring on EC when compared with C. Meanwhile, the distribution of these detected metabolites in various tissues including heart, liver, spleen, lung, kidney, and brain were respectively studied. The results demonstrated that liver and kidney were the most important organs for EC and its metabolites elimination. In conclusion, the newly discovered EC metabolites significantly expanded the understanding on its pharmacological effects and built the foundation for further toxicity and safety studies. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Bioactive compounds of baobab ( Adansonia digitata) pulp from Malawi were investigated. The effect of thermal treatment and storage on selected quality attributes of the juice was also evaluated. Organic compounds were analysed by HPLC; total phenol content (TPC) and total antioxidant activity (FRAP, ABTS and DPPH) were measured by spectrophotometry. Malawi baobab pulp contains high levels of procyanidin B 2 (533 ± 22.6 mg/100 g FW), vitamin C (AA + DHA) (466 ± 2.5 mg/100 g FW), gallic acid (68.5 ± 12.4 mg/100 g FW) and (−)-epicatechin (43.0 ± 3.0 mg/100 g FW) and showed a maximum TPC of 1.89 × 10 3 ± 1.61 mg GAE/100 g FW. The maximum antioxidant activity was 2.81 × 10 3 ± 92.8 mg TEAC/100 g FW for FRAP, 1.52 × 10 3 ± 17.1 mg TEAC/100 g FW for ABTS and 50.9 ± 0.43% DPPH for DPPH. Thermal pasteurisation (72 °C, 15 s) retained vitamin C which further showed extended half-life under refrigeration temperature (6 °C). Procyanidin B 2 , (−)-epicatechin, TPC and antioxidant activity fluctuated during storage. Antioxidant activity was significantly correlated (p ≤ 0.05) with bioactive compounds and TPC. [ABSTRACT FROM AUTHOR]

• Polyphenol–protein reactions between β-lactoglobulin (β-LG) and (−)-epicatechin. • Addition of epicatechin altered the tryptic peptide profiles of β-LG models. • Site-specificity of (−)-epicatechin o -quinones were determined. • Covalent reactions were determined at S27, S30, K60, C66, K69, and C160. • (−)-Epicatechin promoted the formation of methionine sulfoxide. Polyphenol–protein reactions in model solutions of β-lactoglobulin (β-LG) incubated with (−)-epicatechin at 37 °C and 60 °C were monitored by microLC–timsTOF Pro-MS/MS combined with bioinformatics strategies. The addition of (−)-epicatechin to the model solutions resulted in changes in tryptic peptide profiles. Covalent bond formation between (−)-epicatechin o -quinones and β-LG was identified for the residues S27, S30, K60, C66, K69, and C160, with C160 being the predominant binding site. Furthermore, the incubation of β-LG with (−)-epicatechin significantly promoted oxidation, especially for the residues M7 and M24. The reaction of monomeric (−)-epicatechin o -quinone at C160 was also identified in the milk chocolate sample. The adaptation of this study by extending the scope of the reaction products offers significant potential for comprehensive food profiling strategies. [ABSTRACT FROM AUTHOR]

• Anthocyanin condensation reactions in model wine solutions were studied under Pulsed Light treatment. • Anthocyanin loss under the Pulsed Light treatment followed the first-order reaction model. • Delphinidin-3-O-glucoside showed the highest loss during the Pulsed Light treatment and aging. • Pulsed Light treatment caused the formation of new isomers of ethyl-linked products. • Pulsed Light treatment significantly affected the color of the model solutions. The effects of Pulsed Light (PL) technology on the anthocyanin condensation reaction in model wine solutions were investigated. Model wine solutions containing malvidin-3-O-glucoside, cyanidin-3-O-glucoside, and delphinidin-3-O-glucoside were separately prepared with the presence of (−)-epicatechin and acetaldehyde. The solutions were subjected to PL treatment with 2, 4, and 8 J/cm2 energy and stored in 10 °C. The loss of anthocyanin during the treatment and the aging period fitted the first-order reaction model (R2 > 98 %). Delphinidin-3-O-glucoside suffered the highest loss, only 46 % remaining after 60 s treatment; the malvidin-3-O-glucoside showed the lower loss, 72 % remaining after 60 s treatment. Furthermore, the PL treatment significantly influenced the kinetics of anthocyanin loss. The results from LC ESI TOF/Q-TOF MS/MS analysis revealed that in the PL treated samples, more peaks eluted in the chromatogram assigned to anthocyanin ethyl-linked (−)-epicatechin products, suggesting that PL treatment led to the formation of new isomers of anthocyanin ethyl-linked (−)-epicatechin. The color characteristics of the model solutions were affected by the PL treatment and the formation of ethyl-linked products. For example, the ΔE* value for samples treated with 8 J/cm2 increased by 42.52, 55.73, and 45.61 % for malvidin-3-O-glucoside, cyanidin-3-O-glucoside, and delphinidin-3-O-glucoside respectively after 110 days. [ABSTRACT FROM AUTHOR]

Breast cancer, due to its high incidence and mortality, is a public health problem worldwide. Current chemotherapy uses non-specific cytotoxic drugs, which inhibit tumor growth but cause significant adverse effects. (-)-Epicatechin (EC) is part of a large family of biomolecules called flavonoids. It is widely distributed in the plant kingdom; it can be found in green tea, grapes, and cocoa. Several studies in animals and humans have shown that EC induces beneficial effects in the skeletal muscle and the cardiovascular system, reducing risk factors such as arterial hypertension, endothelial dysfunction, damage to skeletal muscle structure, and mitochondrial malfunction by promoting mitochondrial biogenesis, with no adverse effects reported. Recently, we reported that EC had an antitumor effect in a murine triple-negative mammary gland tumor model, decreasing tumoral size and volume and increasing survival by 44%. This work aimed to characterize the effects of flavanol EC on proliferation, migration, and metastasis markers of triple-negative murine breast (4T1) cancer cells in culture. We found proliferation diminished and Bax/Bcl2 ratio increased. When the migration of culture cells was evaluated, we observed a significant reduction in migration. Also, the relative expression of the genes associated with metastasis, Cdh1 , Mtss1 , Pten , Bmrs , Fat1 , and Smad4 , was increased. In conclusion, these results contribute to understanding molecular mechanisms activated by EC that can inhibit metastatic-associated proliferation, migration, and invasion of murine breast cancer cells.

This study characterized the enzymatic ability of a cell-free extract from an acidophilic (+)-catechin degraderBurkholderia oxyphila(OX-01). The crude OX-01 extracts were able to transform (+)-catechin and (−)-epicatechin into (+)-taxifolin via a leucocyanidin intermediate in a two-step oxidation. Enzymatic oxidation at the C-4 position was carried out anaerobically using H2O as an oxygen donor. The C-4 oxidation occurred only in the presence of the 2R-catechin stereoisomer, with the C-3 stereoisomer not affecting the reaction. These results suggest that the OX-01 may have evolved to target both (+)-catechin and (−)-epicatechin, which are major structural units in plants. Proposed anaerobic oxidation pathway of (+)-catechin and (−)-epicatechin byBurkholderia oxyphilaOX-01. [ABSTRACT FROM PUBLISHER]

Obesity and type 2 diabetes (T2D) are major public health concerns. Visceral adipose tissue inflammation is considered a significant contributor to obesity-associated T2D development. We previously showed that the flavan-3-ol (−)-epicatechin (EC) can mitigate insulin resistance in mice fed a high fat diet (HFD). This study investigated the capacity of EC to inhibit visceral adipose tissue inflammation occurring as a consequence of HFD consumption in C57BL/6J mice, and characterized the underlying mechanisms. In association with the development of obesity and insulin resistance, HFD consumption caused inflammation in the visceral adipose tissue as evidenced by activation of the pro-inflammatory transcription factor NF-κB and increased tissue levels of the macrophage marker F4/80, tumor necrosis factor alpha (TNFα), and the chemokine MCP-1. EC supplementation mitigated all these events. In addition, we observed activation of the three branches of the unfolded protein response (UPR), and upregulation of NADPH oxidases NOX4 and NOX2 in visceral fat of mice fed HFD. These can account, at least in part, for the associated oxidative stress and activation of the redox sensitive NF-κB. Notably, EC supplementation mitigated this and the release of pro-inflammatory proteins from metabolically stressed adipocytes. Attenuation of adipocyte endoplasmic reticulum (ER) and oxidative stress by EC could contribute to decreased inflammation and improved visceral adipose tissue insulin sensitivity. Our results support the concept that consumption of EC-rich foods could mitigate obesity-associated insulin resistance through attenuation of adipose tissue inflammation. [ABSTRACT FROM AUTHOR]

Mango (Mangifera indica L.) is abundant in proanthocyanidins (PAs) that are important for human health and plant response to abiotic stresses. However, the molecular mechanisms involved in PA biosynthesis still need to be elucidated. Anthocyanidin reductase (ANR) catalyzes a key step in PA biosynthesis. In this study, three ANR cDNAs (MiANR1-1,1-2,1-3) were isolated from mango, and expressed in Escherichia coli. In vitro enzyme assay showed MiANR proteins convert cyanidin to their corresponding flavan-3-ols, such as (−)-catechin and (−)-epicatechin. Despite high amino acid similarity, the recombinant ANR proteins exhibited differences in enzyme kinetics and cosubstrate preference. MiANR1-2 and MiANR1-3 have the same optimum pH of 4.0 in citrate buffer, while the optimum pH for MiANR1-1 is pH 3.0 in phosphate buffer. MiANR1-1 does not use either NADPH or NADH as co-substrate while MiANR1-2/1-3 use only NADPH as co-substrate. MiANR1-2 has the highest Km and Vmax for cyanidin, followed by MiANR1-3 and MiANR1-1. The overexpression of MiANRs in ban mutant reconstructed the biosynthetic pathway of PAs in the seed coat. These data demonstrate MiANRs can form the ANR pathway, leading to the formation of two types of isomeric flavan-3-ols and PAs in mango.

Anthocyanidin reductase (ANR) is a key enzyme in the ANR biosynthetic pathway of flavan-3-ols and proanthocyanidins (PAs) in plants. Herein, we report characterization of the ANR pathway of flavan-3-ols in Shuchazao tea (Camellia sinesis), which is an elite and widely grown cultivar in China and is rich in flavan-3-ols providing with high nutritional value to human health. In our study, metabolic profiling was preformed to identify two conjugates and four aglycones of flavan-3-ols: (−)-epigallocatechin-gallate [(−)-EGCG], (−)-epicatechin-gallate [(−)-ECG], (−)-epigallocatechin [(−)-EGC], (−)-epicatechin [(−)-EC], (+)-catechin [(+)-Ca], and (+)-gallocatechin [(+)-GC], of which (−)-EGCG, (−)-ECG, (−)-EGC, and (−)-EC accounted for 70–85% of total flavan-3-ols in different tissues. Crude ANR enzyme was extracted from young leaves. Enzymatic assays showed that crude ANR extracts catalyzed cyanidin and delphinidin to (−)-EC and (−)-Ca and (−)-EGC and (−)-GC, respectively, in which (−)-EC and (−)-EGC were major products. Moreover, two ANR cDNAs were cloned from leaves, namely CssANRa and CssANRb. His-Tag fused recombinant CssANRa and CssANRb converted cyanidin and delphinidin to (−)-EC and (−)-Ca and (−)-EGC and (−)-GC, respectively. In addition, (+)-EC was observed from the catalysis of recombinant CssANRa and CssANRb. Further overexpression of the two genes in tobacco led to the formation of PAs in flowers and the reduction of anthocyanins. Taken together, these data indicate that the majority of leaf flavan-3-ols in Shuchazao’s leaves were produced from the ANR pathway.

[Display omitted] • (−)-epicatechin upregulated miRs that participate in skeletal muscle exercise adaptation. • (−)-epicatechin induces muscle hypertrophy. • (−)-epicatechin increases the level of myogenic proteins MyoD and MyoG. The flavanol (−)-epicatechin has exercise-mimetic properties. Besides, several miRNAs play a role in modulating the adaptation of the muscle to different training protocols. However, notwithstanding all information, few studies aimed to determine if (−)-epicatechin can modify the expression of miRNAs related to skeletal muscle development and regeneration. Mice were treated for fifteen days by oral gavage with the flavanol (−)-epicatechin. After treatment, the quadriceps of the mice was dissected, and total RNA was extracted. The expression level of miR-133, -204, -206, -223, -486, and -491 was analyzed by qRT-PCR. We also used bioinformatic analysis to predict the participation of these miRNAs in different skeletal muscle signal transduction pathways. Additionally, we analyzed the level of the myogenic proteins MyoD and myogenin by Western blot and measured the cross-sectional area of muscle fibers stained with E&H. (−)-Epicatechin upregulated the expression of miR-133, -204, -206, -223, and -491 significantly, which was associated with an increase in the level of the myogenic proteins MyoD and Myogenin and an augment in the fiber size. The bioinformatics analysis showed that the studied miRNAs might participate in different signal transduction pathways related to muscle development and adaptation. Our results showed that (−)-epicatechin upregulated miRNAs that participate in skeletal exercise muscle adaptation, induced muscle hypertrophy, and increased the level of myogenic proteins MyoD and MyoG. [ABSTRACT FROM AUTHOR]

To identify dietary phenolic compounds capable of improving vitamin E status, male Sprague-Dawley rats were fed for 4 weeks either a basal diet (control) with 2 g/kg cholesterol and an adequate content of vitamin E or the basal diet fortified with quercetin (Q), (−)-epicatechin (EC), or (+)-catechin (C) at concentrations of 2 g/kg. All three catechol derivatives substantially increased concentrations of α-tocopherol (α-T) in blood plasma and liver. To study potential mechanisms underlying the observed increase of α-T, the capacities of the flavonoids to i) protect α-T from oxidation in LDL exposed to peroxyl radicals, ii) reduce α-tocopheroxyl radicals (α-T · ) in SDS micelles, and iii) inhibit the metabolism of tocopherols in HepG2 cells were determined. All flavonoids protected α-T from oxidation in human LDL ex vivo and dose-dependently reduced the concentrations of α-T · . None of the test compounds affected vitamin E metabolism in the hepatocyte cultures. In conclusion, fortification of the diet of Sprague-Dawley rats with Q, EC, or C considerably improved their vitamin E status. The underlying mechanism does not appear to involve vitamin E metabolism but may involve direct quenching of free radicals or reduction of the α-T · by the flavonoids.

The effect of apple phenolics on the oxidative damage caused to myofibrillar proteins by an in vitro metal-catalyzed oxidation system was investigated. Three pure phenolic compounds (chlorogenic acid, (−)-epicatechin and phloridzin) and an apple peel extract were added to myofibrillar proteins in three concentrations (50, 100 and 200 μM), and a blank treatment was included as a control. All suspensions were subjected to Fe 3+ /H 2 O 2 oxidation at 37 °C during 10 days, and protein oxidation was evaluated as carbonylation (α-amino adipic and γ-glutamic semialdehydes) and Schiff base cross-links. Significant inhibition by apple phenolics was found as compared to the control treatment, with (−)-epicatechin being the most efficient antioxidant and phloridzin showing the weakest antioxidant effect. The higher concentrations of apple extract showed effective antioxidant activity against protein oxidation in myofibrillar proteins, emphasizing the potential of apple by-products as natural inhibitors of protein oxidation in meat products. [ABSTRACT FROM AUTHOR]

In addition to the rich nutritional value, date palm is also used in various ethnobotanical practices for the treatment of various disease conditions. Present investigation was undertaken to examine the neuropharmacological and antinociceptive effect of the ethanol extract of three date cultivars growing in Saudi Arabia, namely Ajwah, Safawy and Sukkari. Neuropharmacological effect was observed by pentobarbitone induced sleeping time, open field, and hole board test. Antinociceptive activity was tested by acetic acid induced writhing and hot plate test. The date extracts were also subjected to HPLC analysis to detect the presence of common bioactive polyphenols. All the three date extracts extended the pentobarbitone induced sleeping time, reduced locomotor activity in open field test and reduced exploratory behaviour in hole board test in mice. The extracts also reduced acetic acid induced writhing and delayed response time in hot plate test. The activities were stronger for Ajwah than the other two date cultivars. HPLC analysis indicated the presence of trans-ferulic acid in all three cultivars, while (+)-catechin and (−)-epicatechin only in Ajwah and Safawy. The observed neuropharmacological and analgesic activity could be partly due to the presence of (+)-catechin, (−)-epicatechin and trans-ferulic acid, three important plant polyphenols well known for their neuroprotective activity and their ability to exert antioxidant activity on brain cells. Present investigation also supports the ethnobotanical use of date palm to provide ameliorating effects in pain and CNS disorders. [ABSTRACT FROM AUTHOR]

Under specific physico-chemical conditions β -lactoglobulin is seen to form fibrils structurally highly similar to those that are formed by the amyloid-like proteins associated with neurodegenerative disorders, such as Alzheimer and Parkinson diseases. In the present study we provide insights on the possible role that the dietary flavonoid (−)-epicatechin plays on β -lactoglobulin fibril formation. Fibril formation is induced by keeping β -lactoglobulin solutions at pH 2.0 and at a temperature of 80 °C for 24 h. Atomic Force Microscopy measurements suggest that, by adding (−)-epicatechin in the solution, fibrils density is visibly lowered. This last observation is confirmed by Fluorescence Correlation Spectroscopy experiments. With the use of Fourier Transform IR spectroscopy we monitored the relative abundances of the secondary structures components during the heating process. We observed that in the presence of (−)-epicatechin the spectral-weight exchange between different secondary structures is partially inhibited. Molecular Dynamics simulations have been able to provide an atomistic explanation of this experimental observation, showing that (−)-epicatechin interacts with β -lactoglobulin mainly via the residues that, normally in the absence of (−)-epicatechin, are involved in β -sheet formation. Unveiling this molecular mechanism is an important step in the process of identifying suitable molecules apt at finely tuning fibril formation like it is desirable to do in food industry applications. [ABSTRACT FROM AUTHOR]

A new simple, rapid and precise RP-HPLC method was developed for the extraction and quantitative estimation of caffeine (C), (−)-epigallocatechin gallate (EGCG), (+)-catechin(Ct), (−)-epicatechin(EC), and (−)-epicatechin gallate (ECG) (collectively named as Tea Powder Bioactives TPBAs) extracted from tea powder using different ratios of ethanol: water. The simultaneous determination of TPBAs was performed using the UV spectrophotometric method which employs the absorbance at 205 nm (λ of caffeine and polyphenols). This method is a gradient based HPLC method with a flow rate of 0.8 mL/min using Inertsil ODS 100 × 4.6 mm, 3 μm column with methanol and ammonium dihydrogen phosphate (pH-2.8) as mobile phase. The method was validated in terms of specificity, precision, linearity, accuracy, limit of quantification (LOQ), and limit of detection (LOD). The linearity of the proposed method was investigated for concentration ranging between 0.5-60 μg/mL with regression co-efficient, R = 0.999-1.0. This method estimates all the TPBAs simultaneously with enhanced precision and linearity as per the ICH guidelines. Also, to confirm the individual TPBA, the antioxidant property of the each TPBA was analyzed which was commensurate with that of the previous reports. [ABSTRACT FROM AUTHOR]

Single-crystal X-ray analysis to 0.6 Å resolution using synchrotron radiation of the inclusion complexes of β-cyclodextrin (β-CD) with (+)-catechin (CA) and (−)-epicatechin (EC) has been carried out to gain atomistic insight into how the inclusion complexation helps to improve tea catechin antioxidant activity. The β-CD–CA complex crystallizes in the monoclinic P 2 1 space group, whereas the β-CD–EC complex crystallizes in both the monoclinic P 2 1 and triclinic P 1 space groups. In comparing the inclusion structures, the β-CD–EC dimeric structure having higher numbers of O H⋯O hydrogen bonds combined with π⋯π interactions is associated with its greater interaction energy, as derived from DFT/B3LYP single-point energy calculations. Detailed structural analysis of the CA, EC conformation and inclusion geometry reveals that the interplay of the intermolecular OH⋯O hydrogen bond stabilized catechol moiety and the protection of OH groups in the β-CD cavity plays a key role in the improvement of antioxidant capacity upon inclusion complexation. [ABSTRACT FROM AUTHOR]

The stability and bioavailability of catechins, a kind of tea polyphenols with health benefit, could be improved by complexing with cyclodextrins. The aim of this study was to investigate the complexation of two geometrical isomers, (+)-catechin and (−)-epicatechin, with hydroxypropyl-β-cyclodextrin (HP-β-CD) in tris–HCl buffer solutions at pH 6.8–8.0 using isothermal titration calorimetry, fluorescence and proton nuclear magnetic resonance spectroscopy. Experimental results showed that these inclusion interactions are primarily enthalpy-driven processes. The complexation constant ( K C ) of EC + HP-β-CD complex was less than that of CA + HP-β-CD at the same temperature and pH value. Temperature and pH studies showed that the K C value decreased with the rise of temperature and pH. Stability study indicated that HP-β-CD showed a stronger protection effect on CA than that on EC. The different inclusion modes between CA and EC were discussed in terms of the discrepancy in their molecular structures. [ABSTRACT FROM AUTHOR]

The flavanol (-)-epicatechin has exercise-mimetic properties. Besides, several miRNAs play a role in modulating the adaptation of the muscle to different training protocols. However, notwithstanding all information, few studies aimed to determine if (-)-epicatechin can modify the expression of miRNAs related to skeletal muscle development and regeneration. Mice were treated for fifteen days by oral gavage with the flavanol (-)-epicatechin. After treatment, the quadriceps of the mice was dissected, and total RNA was extracted. The expression level of miR-133, -204, -206, -223, -486, and -491 was analyzed by qRT-PCR. We also used bioinformatic analysis to predict the participation of these miRNAs in different skeletal muscle signal transduction pathways. Additionally, we analyzed the level of the myogenic proteins MyoD and myogenin by Western blot and measured the cross-sectional area of muscle fibers stained with E&H. (-)-Epicatechin upregulated the expression of miR-133, -204, -206, -223, and -491 significantly, which was associated with an increase in the level of the myogenic proteins MyoD and Myogenin and an augment in the fiber size. The bioinformatics analysis showed that the studied miRNAs might participate in different signal transduction pathways related to muscle development and adaptation. Our results showed that (-)-epicatechin upregulated miRNAs that participate in skeletal exercise muscle adaptation, induced muscle hypertrophy, and increased the level of myogenic proteins MyoD and MyoG., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

A mixture of risperidone and eight major tea catechins: (-)-epicatechin-3-O-gallate (ECg), (-)-epigallocatechin-3-O-gallate (EGCg), (-)-catechin-3-O-gallate (Cg), (-)-gallocatechin-3-O-gallate (GCg), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (+)-catechin (CA), or (+)-gallocatechin (GC), in tartaric acid buffer (pH 3.0) afforded a precipitate. Amounts of risperidone and these catechins in the precipitate were measured by quantitative 1 H-NMR (qNMR). About half or more of risperidone used was precipitated by gallated catechins ECg, EGCg, Cg, and GCg; on the other hand, it was precipitated little by non-gallated catechins EC, EGC, CA, and GC. Furthermore, risperidone was precipitated more by 2,3-trans gallated catechins Cg and GCg than 2,3-cis gallated catechins ECg and EGCg. Regarding the amount of tea catechins in the precipitate obtained by a mixture of risperidone and Catechin Mixture, the amounts of 2,3-cis gallated catechins EGCg and ECg were much larger than those of the other green tea catechins GCg, EC, EGC, CA, and GC. It was considered that risperidone was mainly precipitated by EGCg and ECg in Catechin Mixture. Therefore, it can be concluded that when patients take risperidone with catechin-rich beverages, the efficacy of risperidone reduces, mainly because the 2,3-cis gallated catechins EGCg and ECg form complexes with risperidone and precipitate.

We have provided evidence that the stimulatory effects of (−)-epicatechin ((−)-EPI) on endothelial cell nitric oxide (NO) production may involve the participation of a cell-surface receptor. Thus far, such entity(ies) has not been fully elucidated. The G protein-coupled estrogen receptor (GPER) is a cell-surface receptor that has been linked to protective effects on the cardiovascular system and activation of intracellular signaling pathways (including NO production) similar to those reported with (−)-EPI. In bovine coronary artery endothelial cells (BCAEC) by the use of confocal imaging, we evidence the presence of GPER at the cell-surface and on F-actin filaments. Using in silico studies we document the favorable binding mode between (−)-EPI and GPER. Such binding is comparable to that of the GPER agonist, G1. By the use of selective blockers, we demonstrate that the activation of ERK 1/2 and CaMKII by (−)-EPI is dependent on the GPER/c-SRC/EGFR axis mimicking those effects noted with G1. We also evidence by the use of siRNA the role that GPER has on mediating ERK1/2 activation by (−)-EPI. GPER appears to be coupled to a non Gα i/o or Gα s , protein subtype. To extrapolate our findings to an ex vivo model, we employed phenylephrine pre-contracted aortic rings evidencing that (−)-EPI can mediate vasodilation through GPER activation. In conclusion, we provide evidence that suggests the GPER as a potential mediator of (−)-EPI effects and highlights the important role that GPER may have on cardiovascular system protection. [ABSTRACT FROM AUTHOR]

An increased permeability of the intestinal barrier is proposed as a major event in the pathophysiology of inflammatory bowel diseases (IBD). Tumor necrosis alpha (TNFα) plays a central role in IBD pathogenesis, in part promoting tight function (TJ) barrier dysfunction. Food extracts enriched in (−)-epicatechin (EC) prevent the development or improve the progression of IBD in animal models. This study investigated the capacity of EC to inhibit TNFα-induced permeabilization of Caco-2 cell monolayers, characterizing the underlying mechanisms. Caco-2 cells differentiated into intestinal epithelial cells were incubated in the absence/presence of TNFα, with or without the addition of 0.5–5 μM EC. TNFα triggered cell monolayer permeabilization, decreasing transepithelial electrical resistance (TEER) and increasing the paracellular transport of fluorescein sulfonic acid. The permeabilizing effects of TNFα were not due to Caco-2 cell apoptosis as evaluated by DNA fragmentation, caspase 3 and 9 activation, and cell morphology. EC prevented TNFα-triggered Caco-2 monolayer permeabilization and acted inhibiting the associated: (i) NADPH oxidase (NOX)-mediated increased oxidant production, (ii) NF-κB (IκBα phosphorylation, p50 and RelA nuclear transport, and nuclear NF-κB-DNA binding) and ERK1/2 activation, (iii) increased myosin light kinase expression, and decreased TJ protein ZO-1 levels. In summary, EC prevented TNFα-mediated Caco-2 cell barrier permeabilization in part through the inhibition of NOX/NF-κB activation and downstream TJ disruption. Diets rich in EC could contribute to ameliorate IBD-associated increased intestinal permeability. [ABSTRACT FROM AUTHOR]

Human amoebiasis is an intestinal disease with a global distribution. Due to reports of parasite resistance or susceptibility reduction to metronidazole treatment, there is a renewed interest for the search of new molecules with antiamoebic activity. The flavonoid (−)-epicatechin that was isolated from the Mexican medicinal plant Geranium mexicanum HBK has an in vitro activity against E. histolytica trophozoites, however its molecular effects have been poorly documented. Using a proteomic approach based on two-dimensional gel electrophoresis and mass spectrometry (ESI-MS/MS) analysis, we evidenced that E. histolytica cytoskeleton proteins exhibit differential abundance in response to (−)-epicatechin treatment. Moreover, functional assays revealed modification on pathogenic mechanisms associated with cytoskeleton functionality, namely, adhesion, migration, phagocytosis and cytolysis. Consequently, these data suggested that (−)-epicatechin could affect virulence properties of this human pathogen. Biological significance This work contributes with some advances in the action mechanisms involved in the antiamoebic effect of the flavonoid (−)-epicatechin. We found that this flavonoid has an unusual effect on trophozoites growth that is dependent of its concentration. Additionally, we reported that (−)-epicatechin affects mainly amebic cytoskeleton proteins, which results in alteration on important virulence mechanisms, like adhesion, migration, phagocytosis and cytolysis. This study provides new knowledge about a potential alternative therapy directed to the treatment of amoebiasis. This article is part of a Special Issue entitled: Proteomics, mass spectrometry and peptidomics, Cancun 2013. Guest Editors: César López-Camarillo, Victoria Pando-Robles and Bronwyn Jane Barkla. [ABSTRACT FROM AUTHOR]

Accumulating evidence suggest that diets rich in cocoa flavanols may have beneficial effects on cardiovascular health. The major cocoa flavanol monomer, (−)-epicatechin (EC), is readily absorbed and circulates primarily as glucuronidated, sulfated, and O -methylated metabolites in human plasma. However, cellular metabolism, for example in endothelial cells, is less well defined. In the present study we detail the uptake and cellular metabolism of EC and its major in vivo metabolites, (−)-epicatechin-3′-β- d -glucuronide (E3G), (−)-epicatechin-3′-sulfate (E3S), 3′- O -methyl-(−)-epicatechin-5-sulfate (3ME5S), and 3′- O -methyl-(−)-epicatechin-7-sulfate (3ME7S) in human endothelial (HUVEC), liver (HepG2) and intestinal epithelial cells (Caco-2 monolayer). Our results indicate that EC associates with HUVECs, leading to its intracellular metabolism to 3ME7G and 3ME7S. In contrast, none of the metabolites were taken up by the cells. The metabolic rate and pattern of metabolism in HUVECs was similar to that observed in HepG2 cells, whilst in Caco-2 cells EC was metabolized to E3G, 3ME5G, 3ME7G, 4ME5G, 4ME7G and 3ME7S. Our data support the notion that endothelial cells may contribute significantly to EC metabolism. However, major human circulating metabolites are not accounted for in these model systems underscoring that caution should be taken when drawing conclusions on in vivo flavanol metabolism from in vitro experiments. [ABSTRACT FROM AUTHOR]

Elephantorrhiza elephantina (Burch.) Skeels (Fabaceae) and Pentanisia prunelloides (Klotzsch ex Eckl. & Zeyh.) Walp. (Rubiaceae) are two medicinal plants used extensively in southern Africa to treat various ailments. Often, decoctions and infusions from these two plants are used in combination specifically for stomach ailments. The antimicrobial activities of the methanol and aqueous extracts of the rhizomes of the two plants, as well as the two active ingredients from the plants [(−)-epicatechin and palmitic acid] have been determined apart and in combination against Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 8739) and Bacillus cereus (ATCC 11778). The minimum inhibitory concentration (MIC) values for the aqueous (0.50–16.00 mg/mL) and methanol (0.20–16.00 mg/mL) extracts independently demonstrated varied efficacies depending on the pathogen of study. When the two plants were combined in 1:1 ratios, synergistic to additive interactions (ΣFIC values 0.19–1.00) were noted. Efficacy for the two major compounds ranged between 0.13–0.63 mg/mL and mainly synergistic interactions were noted against E. faecalis and E. coli . The predominantly synergistic interactions noted between E. elephantina and P. prunelloides and major compounds, when tested in various ratios against these pathogens, provide some validation as to the traditional use of these two plants to treat bacterial gastrointestinal infections. [ABSTRACT FROM AUTHOR]

Anthocyanidin reductase (ANR) is an NADPH-/NADH-dependent enzyme that transfers two hydrides to anthocyanidins to produce three types of isomeric flavan-3-ols. This reductase forms the ANR pathway toward the biosynthesis of proanthocyanidins (PAs, which are also called condensed tannins). Here, we report cloning and functional characterization of an ANR (called VbANR) homolog from the leaves of Vitis bellula, a newly developed grape crop in southern China. The open reading frame (ORF) of VbANR is 1,017 bp in length and encodes 339 amino acids. A phylogenetic analysis and an alignment using 17 sequences revealed that VbANR is approximately 99.9 % identical to the ANR homolog from Vitis vinifera. The VbANR ORF is fused to the Trx gene containing a His-tag in the pET32a(+) vector to obtain a pET32a(+)-VbANR construct for expressing the recombinant VbANR. In vitro enzyme assays show that VbANR converts cyanidin, delphinidin, and pelargonidin to their corresponding flavan-3-ols. Enzymatic products include 2 S,3 R- trans- and 2 R,3 R- cis-flavan-3-ols isomers, such as (−)-catechin and (−)-epicatechin. In addition, the third compound that is observed from the enzymatic products is most likely a 2 S,3 S- cis-flavan-3-ol. To analyze the kinetics and optimize pH and temperature values, a UV spectrometry method was developed to quantify the concentrations of total enzymatic products. The optimum pH and temperature values are 4.0 and 40 °C, respectively. The K, K, V, and K/ K values for pelargonidin and delphinidin were similar. In comparison, VbANR exhibits a slightly lower affinity to cyanidin. VbANR uses both NADPH and NADH but prefers to employ NADPH. GFP fusion and confocal microscopy analyses revealed the cytosolic localization of VbANR. The overexpression of VbANR in ban mutants reconstructed the biosynthetic pathway of PAs in the seed coat. These data demonstrate that VbANR forms the ANR pathway, leading to the formation of three types of isomeric flavan-3-ols and PAs in the leaves of V. bellula. [ABSTRACT FROM AUTHOR]

Highlights: [•] Thirteen phenolic compounds were tentatively identified in litchi pulp by HPLC–MS/MS. [•] Litchi pulp of two cultivars significantly increased glucose consumption in cells. [•] Glucose consumption activity significantly correlated with the antioxidant activity. [•] (−)-Epicatechin in litchi pulp may be important for the glucose consumption activity. [•] Hemaoli and Feizixiao have great potential as hypoglycaemic food. [Copyright &y& Elsevier]

Abstract: The heme-containing enzyme myeloperoxidase (MPO) is mainly expressed in polymorphonuclear leukocytes (PMNs), the most abundant immune cell type in the blood. Accordingly, MPO is classically attributed to the innate immune response against pathogens. Yet, new results also show immune-regulatory functions of the halogenating MPO activity including the formation of anti-inflammatory mediators. In this work we tested the ability of the flavonoid (−)-epicatechin to regenerate this enzymatic activity both in vitro at the isolated MPO–H2O2–Cl− system and ex vivo in human PMNs. For all experiments the non-fluorescent dye aminophenyl fluorescein (APF) was used. Upon oxidation by the MPO, the halogenation product hypochlorous acid (HOCl) fluorescein is formed which can be detected e.g. by flow cytometry. The in vitro- and ex vivo-results concordantly show that (−)-epicatechin is a suitable substrate to overcome a compound II accumulation of MPO which was experimentally forced by applying excess hydrogen peroxide. Thereby concentration-dependent effects of the flavan-3-ol were found in both cases and confirmed the proposed mode of action of (−)-epicatechin. The results are in accordance with previous stopped-flow kinetic studies which showed a high reactivity of the polyphenol with MPO compound II. The obtained data may contribute to the explanation of the well-known health promoting effects of (−)-epicatechin. Moreover, the presented study provides new insights into the role of MPO during inflammation. [Copyright &y& Elsevier]

• Longan pericarp ontains high activity of browning related laccases (LACs). • LAC14-4 was purified from the pericarp and showed high activity to epicatechin. • LAC14-4 catalyzes (epi)catechin polymerization in vitro. • LAC14-4 is located in the vacuole and endoplasmic reticulum of the mesocarp cells. Polyphenol oxidase (PPO) has long been considered as the key enzyme responsible for the pericarp browning of longan fruit after harvest. However, due to the overlapping substrate ranges of PPOs and laccases, the contribution of laccases in longan pericarp browning is unclear. In this study, we found that the contents of flavan-3-ols and procyanidin A2/B2 in longan pericarp decreased during browning after harvest. It might be caused by high activity of laccases rather than PPOs. A 100-kDa laccase was purified from the pericarp and its protein sequence was identical to the deduced sequence of LAC14-4. The laccase showed more favored to (−)-epicatechin (EC) than other flavan-3-ols and procyanidin A2/B2 identified in the pericarp. Using EC and (+)-catechin (CT) as substrates, brown products were generated by LAC14-4 and exogenously expressed LAC14-4-3 × HA in vitro ; isomers of procyanidin polymers were detected in the products. Transient expression of LAC14-4-GFP in tobacco leaves showed that LAC14-4 was located in the vacuoles and endoplasmic reticulum. In situ hybridization showed that LAC14-4 mainly expressed in the outer part of mesocarp closed to the brachysclereid layer. The transcript, protein and activity levels of LAC14-4 in pericarp were upregulated during browning. In summary, longan pericarp contains high levels of LAC14-4 that catalyzes the procyanidin polymerization leading to longan pericarp browning. [ABSTRACT FROM AUTHOR]

Abstract: Intervention studies with A-type oligomeric procyanidins from litchi (Litchi chinensis) pericarp (LPOPC) suggested its protective effect against cardiovascular diseases. However, there is no consensus on the absorption and metabolism of LPOPC. It was demonstrated that the main components in LPOPC were (−)-epicatechin, A-type procyanidin dimers, trimers and tetramers. Rats were orally administered different levels of LPOPC (150 and 300mg/kgbw), the procyanidins and their microbial metabolites in urine were identified by HPLC–MS/MS analysis 18h post-administration. Data indicated that seven aromatic acid metabolites excreted were significantly increased by 300mg/kgbw of LPOPC (P < 0.01). However, only (−)-epicatechin and its methylated derivatives were detected in rat plasma 1h after 300mg/kgbw of LPOPC administration. The total EC content absorbed in plasma was only 2.54±0.53μmol/L, indicating that the biological properties of LPOPC should be probably explained by its microbial degraded phenolic acids. [Copyright &y& Elsevier]

Abstract: In the present study, compact high-speed countercurrent chromatographic apparatus was constructed with three columns connected in series. Two sets of columns were prepared from 10mm and 12mm I.D. tubing to form 12L and 15L capacities, respectively. Performance of these columns was compared for the separation of (−)-epicatechin gallate (ECG) from a tea extract by flash countercurrent chromatography (FCCC). In each separation, 200g of the tea extract in 1600mL of mobile phase was loaded onto the column. The 12L column gave 7.5L (35g of ECG) and the 15L column gave 9L (40g of ECG) of ECG solution without impurities. The ECG solution was directly hydrolyzed by tannase into (−)-epicatechin. The hydrolysate was purified by flash chromatography on AB-8 macroporous resin to give 52g of EC (purity 99.1%). This scaled up apparatus could be used for the industrial separation of natural products. [Copyright &y& Elsevier]

A combination of maternal obesity and high-fat diet (HFD) in offspring postnatal life has deleterious effects, and (-)-epicatechin (Epi) treatment can reverse these adverse effects. To investigate whether Epi administration can modify fat mass, muscle mass, and bone mass in male rats descended from obese mothers, fed postnatally on an HFD. Male offspring of mothers fed with control diet formed the control group (C), control group with high-fat diet (CHF), and control group with high-fat diet + epicatechin (CHF + Epi). Male offspring of maternal obesity formed the group with control diet (MO), maternal obesity group with high-fat diet (MOHF), and maternal obesity group with high-fat diet + epicatechin (MOHF + Epi). We measured total fat and weight of visceral adipose tissue by dissection and by dual-energy x-ray absorptiometry scanning body composition. Epicatechin diminished total and visceral pads fat of male offspring of CHF + Epi and MOHF + Epi groups versus to male offspring of CHF and MOHF groups. Besides, epicatechin increased lean mass in CHF + Epi and MOHF + Epi groups, but these changes were not significant. Total body mineral density of the male offspring of CHF, MOHF, and MOHF + Epi groups was significantly higher versus male offspring of C and MO groups. Obesity programming model plus a high-fat postnatal diet presents higher visceral adipose tissue, decreased lean mass, and modified body mineral density when compared with a direct obesity model and its controls. Epicatechin treatment improved body composition; however, it was not able to induce similar values as presented by the controls., (© 2022 Société Française de Pharmacologie et de Thérapeutique.)

Abstract: Pigmentation enhancement in a Chardonnay wine with high flavan-3-ol concentration was examined by irradiating the wine under controlled conditions. Heating the wine in darkness required temperatures in excess of 50°C before enhanced pigmentation became apparent. It was found that ultraviolet and, to a lesser extent, low wavelength visible light contributed to pigment production. The development of pigmentation depended on wine bottle glass colour: Flint>Arctic Blue>French Green>Antique Green. This is in agreement with the transmission characteristics of the bottles with even the darkest (Antique Green) allowing the transmission of some ultraviolet light. Riboflavin, when added to the wine, degraded rapidly when exposed to radiation <400nm. The degradation of riboflavin and the onset of colour development depended on the actual amounts as well as the ratio of riboflavin to flavan-3-ol, suggesting that a complex series of reactions are occurring. A degradation product of riboflavin may be contributing to the increase in absorbance in the visible region observed during light exposure. [Copyright &y& Elsevier]

Abstract: After absorption in the gastrointestinal tract, (−)-epicatechin is extensively transformed into various conjugated metabolites. These metabolites, chemically different from the aglycone forms found in foods, are the compounds that reach the circulatory system and the target organs. Therefore, it is imperative to identify and quantify these circulating metabolites to investigate their roles in the biological effects associated with (−)-epicatechin intake. Using authentic synthetic standards of (−)-epicatechin sulfates, glucuronides, and O-methyl sulfates, a novel LC–MS/MS–MRM analytical methodology to quantify (−)-epicatechin metabolites in biological matrices was developed and validated. The optimized method was subsequently applied to the analysis of plasma and urine metabolites after consumption of dark chocolate, an (−)-epicatechin-rich food, by humans. (−)-Epicatechin-3′-β-d-glucuronide (C max 290±49nM), (−)-epicatechin 3′-sulfate (C max 233±60nM), and 3′-O-methyl epicatechin sulfates substituted in the 4′, 5, and 7 positions were the most relevant (−)-epicatechin metabolites in plasma. When plasmatic metabolites were divided into their substituent groups, it was revealed that (−)-epicatechin glucuronides, sulfates, and O-methyl sulfates represented 33±4, 28±5, and 33±4% of total metabolites (AUC0–24 h), respectively, after dark chocolate consumption. Similar metabolites were found in urine samples collected over 24h. The total urine excretion of (−)-epicatechin was 20±2% of the amount ingested. In conclusion, we describe the entire metabolite profile and its degree of elimination after administration of (−)-epicatechin-containing food. These results will help us understand more precisely the mechanisms and the main metabolites involved in the beneficial physiological effects of flavanols. [Copyright &y& Elsevier]