Catechin Research Articles

Molecular and Functional Characterization of the Key Proanthocyanidin Pathway Enzymes Anthocyanidin Reductases and Leucoanthocyanidin Reductases in Litchi chinensis.

The litchi genome has five anthocyanidin reductase (LcANR) and two leucoanthocyanidin reductase (LcLAR) members. The high expression of LcANR1a/2a and LcLAR1/2 is significantly positively correlated with the abundant proanthocyanidins and (-)-epicatechin (EC) in the pericarp, leaf, root, etc. The recombinant LcANR1a/2a converts cyanidin to both EC and (+)-catechin (CT) (EC:CT ≈ 1:1) and converts delphindin to (+)-gallocatechin and (-)-epigallocatechin; the recombinant LcLAR1/2 converts leucocyanidin to CT. The enzymatic kinetics of the four enzymes are presented, with the respective Km of LcLAR1/2 to leucocyanidin, 19 and 34 μM, and the Vmax, 7 and 5 nmol min-1 mg-1, which are rarely reported for other plants. Overexpression of LcANR1a/2a and LcLAR1/2 in Arabidopsis ban mutant recovered EC and CT biosynthesis respectively in the seeds; however, the EC-only recovery by LcANR1a/2a is inconsistent with their in vitro activity, indicating that the ANR/LAR function is dependent on characteristic molecular contexts in plants and correlated to the distinct PA profiles in litchi.

Stability and degradation mechanism of (−)-epicatechin in thermal processing

(−)-Epicatechin (EC) is a commonly dietary phytochemical that presents multi-physiological activities on human health. Thermal processing is a common method to extract EC, albeit likely to degrade EC considering its thermal instability. In this study, an 85-min non-durable bathing incubation assay was designed to simulate the state of EC in boiling water while cooking. Monitoring of degradation products was performed using ultra-performance liquid chromatography combined with electrospray ionization quadrupole tandem mass spectrometric detection (UPLC-ESI-TSQ-MS/MS). The results revealed that ca. 65.2 % loss of EC was detected in the first 10 min, and over 99.5 % of EC was degraded within 30 min. A total of 22 degradation products were identified based on retention time, full and tandem MS data were the first to be comprehensively reported. Isomerization, oxidation, hydroxylation, dimerization, and ring cleavage were the main chemical reactions that occurred for EC in boiling aqueous solution.

Traffic signal-inspired fluorescence lateral flow immunoassay utilizing self-assembled AIENP@Ni/EC for simultaneous multi-pesticide residue detection

The presence of multiple pesticide residues in fruits and vegetables poses a serious threat to human health. Conventional gold nanoparticles (AuNPs) used in multiplex lateral flow immunoassays (M−LFIA) often exhibit poor sensitivity and potential for misidentification. This study introduces a traffic signal-inspired fluorescent LFIA (T-FLFIA) designed for the simultaneous quantitative detection of chlorothalonil (CTN), paclobutrazol (PBZ), and fipronil (FIP) in cowpea and apple samples. Utilizing the hydrophobic interactions of aggregation-induced emission luminogens (AIEgens) and the coordination of epicatechin (EC) with Ni2+, we developed a novel nanostructure-aggregation-induced emission nanoparticle (AIENP) coated with a metal-polyphenol network of Ni/EC (AIENP@Ni/EC) via a self-assembly method and employed it as fluorescence probe in T-FLFIA. Three distinct colors of AIENP@Ni/EC featuring green, yellow, and red fluorescence were successfully synthesized by coating various AIEgens. This multicolor fluorescence capability facilitates more precise and expedited discrimination among multiple detection targets. High-performance AIE fluorescence probes were fabricated by directly coupling AIENP@Ni/EC with different antibodies through electrostatic interactions, leveraging the exceptional biocompatibility of Ni/EC. The T-FLFIA exhibited sensitive detection of CTN, PBZ, and FIP at concentrations as low as 0.038 ng/mL, 0.025 ng/mL, and 0.046 ng/mL, respectively, with high qualitative accuracy (92.5 %) within a rapid timeframe (5 s). This exceptional performance can be attributed to its outstanding optical properties and distinguishable colors. This approach demonstrated enhanced sensitivity and accuracy, reduced consumption of antibodies and immunoprobes, and a broader detection range compared to single-color AuNPs-M−LFIA. This study introduces a novel, practical, and cost-effective tool for rapid screening of diverse pesticide residues in field settings

(-)-Epicatechin regulates endoplasmic reticulum stress and promotes ferroptosis in lung cancer cells via the PERK/eIF2α/ATF4 signaling pathway.

(-)-Epicatechin (EC) is an active ingredient of Fagopyrum dibtrys (D. Don) Hara and can regulate lung cancer progression. However, the specific regulatory mechanism is poorly understood. This study explored the specific mechanism of EC in the treatment of lung cancer. H460 cells were injected subcutaneously into the left dorsal sides of nude mice to establish an animal model of lung cancer. H460 and H1299 cells and nude mice were treated with different concentrations of EC. The expression levels of related proteins were detected by Western blotting. Cell proliferation, migration, and invasion were detected by CCK-8, colony formation, and Transwell assays. Flow cytometry was used to detect the Ca2+ level in lung cancer cells. Immunohistochemistry was used to detect the expression of Ki-67 in tumor tissues. This study revealed that ferroptosis in lung cancer cells was inhibited during lung cancer development. EC treatment promotes ferroptosis, inhibits the proliferation, migration and invasion of lung cancer cells, and inhibits the formation of tumors in vivo. Ferroptosis inhibitors (Fer-1) weaken the effects of EC on lung cancer cells, whereas a ferroptosis inducer (erastin) further promotes the effects of EC. In addition, endoplasmic reticulum (ER) stress is involved in the EC-induced ferroptosis of lung cancer cells, and treatment with GSK, an inhibitor of the ER stress protein PERK, can reverse the effect of EC. EC therapy activates the PERK-eIF2α-ATF4 signaling pathway to increase ER stress, thereby promoting ferroptosis in lung cancer cells and inhibiting the occurrence and development of lung cancer. Our research suggests that EC may become a drug candidate for treating lung cancer.

Assessing the antiproliferative properties of various teas against the DU-145 prostate cancer cell line: A combined in vitro and in silico investigation

BackgroundPhytotherapy emerges as a promising solution to the challenges posed by cancer treatment. Black, green, and purple teas, renowned for their antioxidant properties, exhibit efficacy against various cancers, including prostate cancer. Study DesignThis was an experimental study conducted from the Kenya Medical Research Institute (KEMRI). Aim of the Studythe present study aimed to evaluate the Cytotoxic effect of black, green and purple teas against prostate cancer cell line DU-145 and in silico prediction of Tea catechins interaction with prostate cancer proteins such as 3D-crystal structures of Androgen-receptor(5T8E) and Human p38 MAPK(1KV2). MethodsThe study started by quantifying tea catechins (Epigallocatechin gallate (EGCG), Epigallocatechin EGC, Epicatechin gallate (ECG) and Epicatechin (EC) with high-liquid chromatography (HPLC), cytotoxicity analysis of black, green and purple tea crude extracts against DU-145 cell line at 24hr and 48 hrs by Resazurin assay and molecular docking was performed with Autodock Vina 1.1.2 software. ResultsEGCG appeared the most predominant catechin with 552.2 ± 10.61 (mg g-1 DW) while EC was the lowest detected with 118.08 ± 9.45 (mg g-1 DW). Purple tea extract exhibited high antiproliferative activity with IC50 of 98.69±1.99 µg/ml at 24hr and 91.21±6.91 µg/ml at 48hr, green tea followed with 121 ± 5.97µg/ml at 24hr and 107.1 ± 2.03 µg/ml at 48hr IC50; black tea was the least effective tea at both 24hr and 48hr with IC50 of 290.8 ± 2.46µg/ml and 237.8 ± 5.59µg/ml respectively. Prediction of catechin target genes and Prostate cancer (Pca)-related genes discovered 121 catechin target genes and 34,926 Pca-related genes. EGC exhibited high binding interaction to 5T8E with the lowest affinity of -9.1Kcal/mol followed by EGCG at -8.4 (Kcal/mol then EC with -8.2 (Kcal/mol) and EGC at -8.1 (Kcal/mol). Catechins interaction with 1KV2 was in the following order EGCG (-9.4 Kcal/mol) ˃ECG (-8.2 Kcal/mol) ˃EC (-8.2 Kcal/mol) ˃EGC (-8.1 Kcal/mol). ConclusionIn vitro experiment detected a very significant antiproliferative activity of black, green and purple tea crude extracts against the DU-145 cell line; furthermore, in silico analysis revealed a strong binding interaction with proteins associated with prostate cancer, indicating that black, green, and purple teas, along with catechins, hold promise as potential herbal remedies for combating prostate cancer.

Protective Role of (-)-Epicatechin on Trimethylamine-N-Oxide (TMAO)-Induced Cardiac Hypertrophy via SP1/SIRT1/SUMO1 Signaling Pathway.

(-)-Epicatechin (EPI) is beneficial for cardiovascular health. Trimethylamine N-oxide (TMAO), a gut microbe-derived food metabolite, is strongly associated with the risk of cardiovascular diseases. However, the effects and underlying mechanisms of EPI on TMAO-induced cardiac hypertrophy remain unclear. This study aimed to determine whether EPI inhibits TMAO-induced cardiac hypertrophy. Plasma levels of TMAO in control participantsand patients with cardiac hypertrophy were measured and analyzed. Male C57BL/6 mice were randomly divided into control group, TMAO group, EPI group and TMAO + EPI group. According to the groups assignments, mice received intraperitoneal (i.p.) injection of normal saline or i.p. injection of TMAO (150mg/kg/day) for 14days. The EPI group was given intragastric (i.g.) administration of EPI alone (1mg/kg/day) for 21days, and TMAO + EPI group received i.g. administration of EPI for 7days before starting i.p. injection of TMAO, continuing until the end of the TMAO treatment. Histological analyses of the mice's hearts was accessed by H&E and Masson staining. In vitro, H9c2 cells were induced to hypertrophy by TMAO (10µM) for 24h and were pre-treated with or without EPI (10µM) for 1h. Protein level of cardiac hypertrophy markers and Sp1/SIRT1/SUMO1 pathway were determined by western blot. The plasma level of TMAO was 2.66 ± 1.59μmol/L in patients with cardiac hypertrophy and 0.62 ± 0.30μmol/L in control participants. EPI attenuated TMAO-induced hypertrophy in H9c2 cells. In vivo, TMAO induced cardiac hypertrophy and impaired the cardiac function of mice. Pathological staining showed that TMAO induced cardiac hypertrophy and collagen deposition in mice. EPI treatment improved the cardiac function, inhibited the myocardial hypertrophy induced by TMAO. EPI significantly attenuated the TMAO-induced upregulation of ANP and BNP and the downregulation of SP1, SIRT1 and SUMO1 in vivo and in vitro. EPI may suppress TMAO-induced cardiac hypertrophy by activating the Sp1/SIRT1/SUMO1 signaling pathway.

Exploring the Therapeutic Potential of Green Tea (Camellia sinensis L.) in Anti-Aging: A Comprehensive Review of Mechanisms and Findings.

Green tea (GT) is rich in Phyto-active compounds such as epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), epicatechin (EC), catechin, and tannic acid, which exhibit synergistic effects when combined. Preclinical studies demonstrate that GT and its compounds can reduce reactive oxygen species (ROS), enhance antioxidant capacity, and alleviate aging-related issues such as memory impairments, cognitive decline, and shortened lifespan. Clinical trials corroborate the efficacy of topical GT formulations in improving skin tone, texture, and elasticity and reducing wrinkles. The present manuscript summarizes the recent update on the anti-aging potential of GT and its possible mechanisms. The literature survey suggested that GT consumption is linked to improved cognition, reduced depression levels, and activation of pathways in model organisms like C. elegans. Additionally, tea polyphenols enhance fibroblast mitophagy, boost hippocampal synaptic plasticity in rodents, and mitigate age-related cognitive decline. Moreover, EGCG exhibits anti-aging properties by reducing TNF-induced MMP-1 expression, suppressing ERK signaling, and inhibiting MEK and Src phosphorylation in human dermal fibroblasts. In the context of skin permeation and deposition, optimized transpersonal formulation (TF) incorporating EGCG and hyaluronic acid (HA) demonstrated significantly increased skin permeation and deposition of EGCG compared to plain EGCG. Furthermore, EGCG protects cardiomyocytes via the PPARγ pathway and combats age-related muscle loss through miRNA-486-5p regulation, AKT activation, and FoxO1a-mediated expression of MuRF1 and Atrogin-1. In conclusion, the regular consumption of GT holds promise for promoting physical and mental health, delaying brain and skin aging, and improving overall health by enhancing total antioxidant capacity.

An improved deep convolutional generative adversarial network for quantification of catechins in fermented black tea

The rapid and non-destructive quantification of catechins in fermented black tea is crucial for evaluating the quality of black tea. The combination of hyperspectral imaging and chemometrics has been applied for quantitative detection, but its performance is usually constrained by the limited dataset size. Targeted at the challenge of insufficient samples in regression analysis of catechins, this study proposes an improved deep convolutional generative adversarial network with labeling module, named as DCGAN-L for hyperspectral data augmentation. The DCGAN-L consists of the spectral and label generating modules. First the synthetic spectra were generated, and an indicator was proposed to evaluate their quality. Then, the corresponding label values were generated, including epicatechin gallate (ECG), epicatechin (EGC), catechin (C), and total catechin (CC). For label generating, the Euclidean distances between the synthetic spectrum and all true spectra were measured, followed by allocating weights for calculating the label values based on these distances. Subsequently, the training dataset was augmented with the generated synthetic data. The effect of data augmentation was finally evaluated based on two regression models of random forest (RF) and broad learning system (BLS) for the quantification of catechins. Compared with the results before data augmentation, the average R2 of RF and BLS models increased by 0.044 and 0.164, respectively. The proposed DCGAN-L model allows for the rapid, non-destructive quantification of catechins in black tea in the case of limited sample size.

A glimpse through the origin, composition and biomedical applications of green tea and its polyphenols: A review

Green tea is an aromatic healthy beverage that is the least processed type of tea, containing numerous bioactive components beneficial to humans. It is produced from the plant Camelia sinensis, a shrub native to Asia. This article reviews the literature review on the origin, manufacturing, composition, biomedical applications and health benefits of green tea and its polyphenols. The main bioactive components of green tea are polyphenols, primarily flavonoids. Catechins are the main flavonoids present in tea. These high-potential compounds can stimulate certain enzymes and alter cellular functions by preventing the oxidation of biomolecules due to their antioxidant properties. The catechins found in tea include (-) –epicatechin (EC), (-) epigallocatechin (EGC), (-)-epicatechin-3-gallate (ECG) and epigallocatechin -3-gallate (EGCG). Epigallocatechin gallate (EGCG) is the most prominent catechin in fresh leaves, constituting around 50-60 % of the flavonoids. EGCG is the active component with significant health benefits. These catechins contribute to therapeutic actions and the prevention of infections. Recent research on green tea suggests various applications based on its medicinal value to reduce the risk of many diseases.

Effect of epicatechin gallate on the glycosylation of soybean protein isolate-lutein complexes with inulin-type fructans and the protective failure point of glycosylated proteins

In recent years, the application of natural extracts such as proteins modified to protect lutein has become a potential technology, but modified proteins lose their protective function towards lutein after a period of time. So far, very few studies have been conducted on the modified proteins after losing their protective function. Therefore, the present study investigate the effect of different polyphenols in tea polyphenols (GTP) on glycosylated soybean protein isolate-lutein (GSPI-lutein) complexes with inulin-type fructans and the GSPI after losing their protective. Screening for various types of polyphenols in tea polyphenols (GTP) revealed that epicatechin gallate (ECG) was mainly responsible for disrupting the protective efficacy of lutein and shortening the protection time from 32 to 24 h. Epicatechin (EC) exhibited the strongest protective efficacy, with the protection time prolonged to 14 days. Meanwhile, the protective efficacy of the modified proteins for lutein was lost after a period of time. Following the loss of protective ability, the a-helix and the total mercapto contents decreased, and the loose porous structure disappeared. This study explored the protective effect of modified proteins on natural pigments, but we were unable to identify the specific functional sites of the proteins involved in the reaction process.

Epicatechin ameliorates palmitate-induced insulin resistance in C2C12 myogenic cells by alleviating oxidative stress and activating the AMPK/ACC pathway

ABSTRACT Epicatechin (EC) is a water-soluble natural organic compound belonging to the flavanol class of compounds. It exhibits various physiological activities such as anti-inflammatory, antioxidant, treatment of mitochondrial diseases, and prevention of cardiovascular diseases.To examineEC’s impact and mechanism on adult myoblasts’ insulin resistance. The effects of various EC concentrations on the viability of C2C12 adult myoblasts were measured, as were glucose consumption and glycogen content; in vitro antioxidant activity of EC was measured; cellular oxidative marker content and apoptosis were measured; and protein expression was detected by Western blot. A model of insulin resistance in C2C12 myogenic cells was established using palmitic acid. EC significantly increased the glucose consumption and glycogen content; EC increased the levels of CAT, SOD and GSH and decreased the levels of NO, MDA and ROS; EC decreased the apoptosis rate of cells; EC treatment upregulated the levels of GLUT4, p-AMPK, p-ACC, NRF2, and HO-1 proteins. These results suggest that EC can regulate the NRF2/HO-1 signaling pathway, enhance GLUT4 transport, activate AMPK/ACC pathway, enhance cellular uptake of glucose, thus effectively improving insulin resistance in C2C12 cells.

Tea's Characteristic Components Eliminate Acrylamide in the Maillard Model System.

This study investigated the effects of various characteristic components of tea-theaflavins, catechins, thearubigins, theasinensins, theanine, catechin (C), catechin gallate (CG), epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin (GC), and gallocatechin gallate (GCG)-on acrylamide formation. The results revealed that most of tea's characteristic components could significantly eliminate acrylamide, ranked from highest to lowest as follows: GC (55.73%) > EC (46.31%) > theaflavins (44.91%) > CG (40.73%) > thearubigins (37.36%) > ECG (37.03%) > EGCG (27.37%) > theabrownine (22.54%) > GCG (16.21%) > catechins (10.14%) > C (7.48%). Synergistic elimination effects were observed with thearubigins + EC + GC + CG, thearubigins + EC + CG, thearubigins + EC + GC, theaflavins + GC + CG, and thearubigins + theaflavins, with the reduction rates being 73.99%, 72.67%, 67.62%, 71.03%, and 65.74%, respectively. Tea's components reduced the numbers of persistent free radicals to prevent acrylamide formation in the model system. The results provide a theoretical basis for the development of low-acrylamide foods and the application of tea resources in the food industry.

Epicatechin and β-Glucan from Whole Highland Barley Grain Synergistic Benefit on Attenuating Hyperglycemia via Improving Hepatic Glucose Metabolism in Diabetic C57BL/6J Mice.

Our previous study proved that epicatechin (EC) and β-glucan (BG) from whole-grain highland barley synergistically modulate glucose metabolism in insulin-resistant HepG2 cells. However, the main target and the mechanism underlying the modulation of glucose metabolism in vivo remain largely unknown. In this study, cell transfection assay and microscale thermophoresis analysis revealed that EC and BG could directly bind to the insulin receptor (IR) and mammalian receptor for rapamycin (mTOR), respectively. Molecular dynamic analysis indicated that the key amino acids of binding sites were Asp, Met, Val, Lys, Ser, and Tys. EC supplementation upregulated the IRS-1/PI3K/Akt pathway, while BG upregulated the mTOR/Akt pathway. Notably, supplementation with EC + BG significantly increased Akt and glucose transporter type 4 (GLUT4) protein expressions, while decreasing glycogen synthase kinase 3β (GSK-3β) expression in liver cells as compared to the individual effects of EC and BG, indicating their synergistic effect on improving hepatic glucose uptake and glycogen synthesis. Consistently, supplementation with EC + BG significantly decreased blood glucose levels and improved oral glucose tolerance compared to EC and BG. Therefore, combined supplementation with EC and BG may bind to corresponding receptors, targeting synergistic activation of Akt expression, leading to the improvement of hepatic glucose metabolism and thereby ameliorating hyperglycemia in vivo.

Hyperspectral guidance for summer tea processing: Enhancing taste and aroma through short‐term cycled heaping

AbstractTo reduce the unpleasant flavor in tea infusion made from summer fresh leaves and lessen tea resource wastage, a short‐term cycled heaping method, addressing the temperature/moisture variations during prolonged heaping, was introduced to produce high‐quality yellow tea with significantly enhanced taste and aroma. Furthermore, a hyperspectral approach was developed to anticipate such improvements. Specifically, short‐term cycled heaping reduced summer tea's astringency and bitterness while increasing sweetness. Using near‐infrared spectroscopy, the multiplicative scatter correction (MSC)–support vector machine (SVM) model predicted tea umami with 66.25% precision and richness with 77.64% accuracy via standard normal variate (SNV)–SVM, based on epigallocatechin (EGC), epicatechin (EC), and gallocatechin gallate (GCG) variations. Aroma enhancement was forecasted by a hyperspectral–electronic nose regression model, achieving over 81.50% prediction accuracy for summer tea aromas in the visible spectrum and surpassing 73.45% in the near‐infrared domain, primarily attributed to pentanal, propanal, toluene, ethyl propionate, and 2,3‐pentanedione variations. Overall, hyperspectral‐guided summer tea processing, particularly for summer‐harvested leaves, shows potential in offering a valuable screening tool, enhancing quality, and efficiency in the tea industry and promoting sustainable development.

(+)-catechin protects PC12 cells against CORT-induced oxidative stress and pyroptosis through the pathways of PI3K/AKT and Nrf2/HO-1/NF-κB.

Pyroptosis induced by oxidative stress is a significant contributor to mental health disorders, including depression (+)-Catechin (CA), a polyphenolic compound prevalent in various food sources, has been substantiated by prior research to exhibit potent antioxidant properties and potential antidepressant effects. Nonetheless, the precise antidepressive mechanisms and effects of CA remain incompletely elucidated. In this study, we employed corticosterone (CORT) and PC12 cells to develop a cellular model of depression, aiming to investigate the protective effects of CA against CORT-induced cellular damage. Our objective was to elucidate the underlying mechanisms of protective action. We utilized transcriptomic analysis to identify differentially expressed genes and employed bioinformatics approaches to predict the potential mechanisms of CA's protective effects in PC12 cells. These transcriptomic predictions were subsequently validated through western blot analysis. The findings indicated that CA possesses the capacity to mitigate oxidative stress and suppress pyroptosis in PC12 cells via the activation of the PI3K/AKT signaling pathway. This activation subsequently modulates the Nrf2/HO1/NF-κB pathways, thereby providing protection to PC12 cells against damage induced by CORT. Furthermore, we investigated the interaction between CA and the Keap1 protein employing molecular docking and protein thermal shift assays. We propose that CA can activate Nrf2 through two mechanisms to decrease reactive oxygen species (ROS) levels and inhibit pyroptosis: one mechanism involves the activation of the PI3K/AKT signaling pathway, and the other involves direct binding to Keap1, leading to an increase in p-Nrf2.

Inhibitory Effect and Mechanism of Epigallocatechin Gallate on the Differentiation of 3T3-L1 Preadipocytes.

Green tea possesses a range of beneficial effects, including anti-obesity, antioxidant, and anti-inflammatory properties, owing to its biologically active components, primarily catechins such as epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), and epigallocatechin gallate (EGCG). However, few studies have investigated the four catechin monomers simultaneously, and the molecular mechanisms of their anti-obesity effects have not been fully elucidated. In this study, we investigated the effects of four catechin monomers on the differentiation of 3T3-L1 preadipocytes of mice. Our findings demonstrated that four catechin monomers EC/ECG/EGC/EGCG (12, 25, 50 µM) dose-dependently inhibited the differentiation of 3T3-L1 preadipocytes and reduced triglyceride content. EGCG exhibited the most potent inhibitory effect with an optimal concentration of 50 µM. In addition, transcriptome sequencing and lipidomic analysis of EGCG-treated 3T3-L1 preadipocytes revealed that Ptgs2 and Pim1 were the most differentially expressed genes involved in regulating adipocyte differentiation. The results suggested that EGCG up-regulated the expression of the Pla2g2e gene and down-regulated the expression of the Pla2g4a and Pla2g2a genes via the glycerophospholipid metabolic pathway, which subsequently elevated lysophosphatidylcholine (LPC) levels, influencing the differentiation process of 3T3-L1 preadipocytes.

Epicatechin ameliorates glucose intolerance and hepatotoxicity in sodium arsenite-treated mice

Arsenic is a metalloid found in the environment that causes toxic effects in different organs, mainly the liver. This study aimed to investigate the protective effects of epicatechin (EC), a natural flavonol, on glucose intolerance (GI) and liver toxicity caused by sodium arsenite (SA) in mice. Our findings showed that SA exposure led to the development of GI. Liver tissue damage and decreased pancreatic Langerhans islet size were also observed in this study. Mice exposed to SA exhibited hepatic oxidative damage, indicated by reduced antioxidant markers (such as superoxide dismutase, catalase, glutathione peroxidase, and glutathione), along with elevated levels of thiobarbituric acid reactive substances. SA administration elevated the serum activities of liver enzymes alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase. Furthermore, notable increases in the levels of inflammatory and apoptotic markers (Toll-like receptor 4, nuclear factor-kappa B, tumor necrosis factor-α, nitric oxide, B-cell lymphoma-2, and cysteine aspartate-specific protease-3) were observed in the liver. Treatment of SA-exposed mice with EC considerably reversed these biochemical and histological changes. This study demonstrated the beneficial effects of EC in ameliorating SA-induced hyperglycemia and hepatotoxicity due to its ability to enhance the antioxidant system by modulating inflammation and apoptosis.

Epicatechin and β-glucan from whole highland barley grain ameliorates hyperlipidemia associated with attenuating intestinal barrier dysfunction and modulating gut microbiota in high-fat-diet-fed mice

Hyperlipidemia is associated with intestinal barrier dysfunction and gut microbiota dysbiosis. Here, we aimed at investigating whether epicatechin (EC) and β-glucan (BG) from whole highland barley grain alleviated hyperlipidemia associated with ameliorating intestinal barrier dysfunction and modulating gut microbiota dysbiosis in high-fat-diet-induced mice. It was observed that EC and BG significantly improved serum lipid disorders and up-regulated expression of PPARα protein and genes. Supplementation of EC and BG attenuated intestinal barrier dysfunction via promoting goblet cells proliferation and tight junctions. Supplementation of EC and BG prevented high fat diet-induced gut microbiota dysbiosis via modulating the relative abundance of Ruminococcaceae, Lactobacillus, Desulfovibrio, Lactococcus, Allobaculum and Akkermansia, and the improving of short chain fatty acid contents. Notably, combination of EC and BG showed synergistic effect on activating PPARα expression, improving colonic physical barrier dysfunction and the relative abundance of Lactobacillus and Desulfovibrio, which may help explain the effect of whole grain highland barley on alleviating hyperlipidemia.

Characterization of a longan pericarp browning related peroxidase with a focus on its role in proanthocyanidin and lignin polymerization

The longan pericarp turns brown dramatically after harvesting, but the mechanism is not well understood. In this work, two peroxidases were purified from longan pericarp and found to be identical to the class III peroxidases PRX53-2 and PRX53-3. In vitro, PRX53-2/3 catalyzed the browning of several pericarp abundant proanthocyanidin and lignin monomers, such as (−)-epicatechin (EC), (+)-catechin (CT) and coniferyl alcohol (ConA). PRX53–2 was upregulated and highly-expressed, while PRX53-3 was expressed at low levels after harvesting; thus, PRX53-2 was considered a browning-related gene. The reaction with both proanthocyanidin and lignin presented a greater degree of brown coloration compared to the single substrate reactions. Several procyanidins isomers, EC-ConA and CT-ConA were detected in the double-substrate reaction. These results not only demonstrate that the effects of PRX53-2 on proanthocyanidin and lignin polymerization may be crucial for longan pericarp browning, but also help in developing new strategies or preservatives to delay pericarp browning.

Green Tea Polyphenol (-)-Epicatechin Pretreatment Mitigates Hepatic Steatosis in an In Vitro MASLD Model.

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease (NAFLD), is becoming more prominent globally due to an increase in the prevalence of obesity, dyslipidemia, and type 2 diabetes. A great deal of studies have proposed potential treatments for MASLD, with few of them demonstrating promising results. The aim of this study was to investigate the potential effects of (-)-epicatechin (EPI) on the development of MASLD in an in vitro model using the HepG2 cell line by determining the metabolic viability of the cells and the levels of PPARα, PPARγ, and GSH. HepG2 cells were pretreated with 10, 30, 50, and 100 μM EPI for 4 h to assess the potential effects of EPI on lipid metabolism. A MASLD cell culture model was established using HepG2 hepatocytes which were exposed to 1.5 mM oleic acid (OA) for 24 h. Moreover, colorimetric MTS assay was used in order to determine the metabolic viability of the cells, PPARα and PPARγ protein levels were determined using enzyme-linked immunosorbent assay (ELISA), and lipid accumulation was visualized using the Oil Red O Staining method. Also, the levels of intracellular glutathione (GSH) were measured to determine the level of oxidative stress. EPI was shown to increase the metabolic viability of the cells treated with OA. The metabolic viability of HepG2 cells, after 24 h incubation with OA, was significantly decreased, with a metabolic viability of 71%, compared to the cells pretreated with EPI, where the metabolic viability was 74-86% with respect to the concentration of EPI used in the experiment. Furthermore, the levels of PPARα, PPARγ, and GSH exhibited a decrease in response to increasing EPI concentrations. Pretreatment with EPI has demonstrated a great effect on the levels of PPARα, PPARγ, and GSH in vitro. Therefore, considering that EPI mediates lipid metabolism in MASLD, it should be considered a promising hepatoprotective agent in future research.