Epigallocatechin Research Articles

The relationship between microbial dynamics and dominant chemical components during Liupao tea processing

Liupao tea is one kind of dark tea with a unique flavor that can be attributed to the microbiome. Howerver, the role of the microbiome is unknown in pile fermention of Liupao tea. Illumina MiSeq sequencing technology was used in this study to analyze microbial community composition during Liupao tea pile-fermentation. The relationship between microbial colonies and dominant chemical components was also evaluated using Pearson analysis. The result shown that contents of cafeine, gallic acid, free amino acids (Free AA), water-soluble pectins (WSP), tea polysaccharides (TPS), and water-soluble carbohydrate (WSC) all increased during fermentation while contents of epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), gallocatechin gallate (GCG), epicatechin (EC), catechins (+C), water extract (WE), tea polyphenols (TP) and flavonoids decreased. The dominant microbial community succession comprised Sphingomonas (23.68%), Methylobacterium (17.67%), Chryseobacterium (12.55), Aspergillus (16.70%), Cladosporium (8.36%), Penicillium (6.07%), and Blastobotrys (1.54%) in the early stage of fermentation, followed by Staphylococcus (59.05%), Brachybacterium (9.66%), Kocuria (9.81%), Blastobotrys (65.07%), Aspergillus (21.10%), and Rasamsonia (11.06%) at later stages. Amongst these, relative abundances of Lactobacillus in probiotics in middle and late fermentation remained relatively high. Genus of Aspergillus, Blastobotrys, Brachybacterium and Kocuria were signifcantly (P< 0.05) correlated with TP, WSP, WSC, FreeAAs, catechins, flavonoids, cafeine and gallic acid. Therefore, the dominant microbiome in pile fermention of Liupao tea were mainly characterized by Staphylococcus, Aspergillus and other genus, meanwhile Aspergillus, Blastobotrys, Brachybacterium and other genus played an important role in quality formation. This research provides new insights into the relationship between microorganisms and product quality and the development of functional Liupao tea.

Green Tea Suppresses Brain Aging.

Epidemiological studies have demonstrated that the intake of green tea is effective in reducing the risk of dementia. The most important component of green tea is epigallocatechin gallate (EGCG). Both EGCG and epigallocatechin (EGC) have been suggested to cross the blood–brain barrier to reach the brain parenchyma, but EGCG has been found to be more effective than EGC in promoting neuronal differentiation. It has also been suggested that the products of EGCG decomposition by the intestinal microbiota promote the differentiation of nerve cells and that both EGCG and its degradation products act on nerve cells with a time lag. On the other hand, the free amino acids theanine and arginine contained in green tea have stress-reducing effects. While long-term stress accelerates the aging of the brain, theanine and arginine suppress the aging of the brain due to their anti-stress effect. Since this effect is counteracted by EGCG and caffeine, the ratios between these green tea components are important for the anti-stress action. In this review, we describe how green tea suppresses brain aging, through the activation of nerve cells by both EGCG and its degradation products, and the reductions in stress achieved by theanine and arginine.

Weak Binding of Epigallocatechin to α-Lactalbumin Greatly Improves Its Stability and Uptake by Caco-2 Cells.

Improving the stability and bioavailability of catechins is of great importance. Epigallocatechin (EGC), the major catechin in green tea, is a potent antioxidant with numerous attributed health benefits. However, the low permeability and stability limit its enrichment in the diet for preventive medicine. In this study, we explored the interaction of EGC and α-lactalbumin by spectroscopic, thermodynamic, and crystallographic methods. The isothermal titration calorimetry experiments elucidated that α-lactalbumin binds to EGC at a ratio of 1:1 with a low affinity of (4.01 ± 0.11) × 105 M-1. A crystal structure solved at a high resolution (1.2 Å) provided direct evidence for the weak interaction between EGC and α-lactalbumin at an atomic level. The novel binding site was discovered at the exterior surface of α-lactalbumin for the first time, supporting a new binding behavior. Consequently, our results demonstrated that the binding of α-lactalbumin to EGC could protect EGC against light-induced, thermal-induced, and pH-induced damage. More importantly, the formed complex has better bioaccessibility than unbound EGC, which was approved by a cell absorption experiment. Such research is beneficial for designing protein-based nanocarriers for polyphenols.

Maltodextrin encapsulation improves thermal and pH stability of green tea extract catechins

This study aimed to trap green tea extract (GTE) with maltodextrin (MD) to protect catechins from high temperatures, pH variations, and storage. GTE:MD microparticles (19.35:80.65% wt/wt) were obtained by spray drying, producing microparticles (26 μm) with a trapping efficiency of 63%, containing epigallocatechin gallate (EGCG), gallocatechin gallate, epigallocatechin (EGC), epicatechin, and catechin. The free GTE evaporated at 43℃, loosed 50% of its weight at 100℃, and decomposed at 130℃. The microparticles started to weight loss at 75℃ and decomposed at 290℃. The EGCG and EGC content of the free GTE completely depleted after 30 days at pH 7 and pH 6, respectively. However, the microparticles increased their EGCG content to 121% after 30 days at pH 7 and reduced 3.5% the EGC content after 30 days at pH 6. MD was an effective barrier capable of stabilizing the GTE’s polyphenolic content and antioxidant capacity. Practical applications The bioactive compounds of the green tea extracts (GTEs) are catechins with antioxidant activity; however, these compounds and their activity may decrease with the epimerization caused by high temperatures, pH variations, and storage. The immobilization of GTE in maltodextrin (MD) preserved its polyphenols’ chemical structures and their antioxidant capacity at different pH and storage times; in addition, the MD immobilization offered thermal protection to the GTE. The results of our study allow us to advance the knowledge in the field, understanding the interactions between GTE components and MD molecules and the possibility of a commercial application of our study.

The catechins profile and antioxidant activity in different types of green tea bags

Tea and mainly green tea as a rich source of antioxidants has been widely known for some time. The antioxidant capacity of tea including green tea is mainly due to its catechins content. The objective of this study was to determine the relationship between the ORAC value and the catechins content. Regular and decaffeinated commercial green tea bags commonly consumed in the United Kingdom (UK) have been examined using Reversed-Phase High-pressure Liquid Chromatography (RP-HPLC). Teabags were purchased from different local supermarkets in the UK and extracted with natural mineral water at temperature 100°C for 9 minutes at the pre-adjusted pH 4. The level of four catechins (Epi-structured) for the thirteen types of green tea were separated and determined by HPLC analysis, i.e. ()-epigallocatechin (EGC), ()-epicatechin (EC), ()-epigallocatechin-3-gallate (EGCG) and ()-epicatechin gallate (ECG). The standard graphs were validated using certified reference catechins supplied by the Laboratory of the Government Chemist (LGC). The levels of total catechins and oxygen radical absorbance capacity (ORAC) values varied from 34.61to 204.55 mg/g, 830.19- 4197.81 Trolox equivalents/g tea bags for thirteen types of green teas respectively. It was clear from the results of this study that there was a significant linear and positive correlation (r = 0.951, df = 12, p &lt; 0.05) is found to exist between the total catechins contents and ORAC values. It can be concluded that the results of catechins measurements coupled to this; the well-known ORAC assay was successfully modified to measure the antioxidant capacity of the green tea extracts throughout this study. Furthermore, the higher the level of catechins the higher is the antioxidant capacity of the tea. This may stimulus consumers in selecting the type of tea and tea brewing times, exhibiting more health benefits. Nevertheless, the differences between the studied brands are owing to shelf life, production and storage conditions.&#x0D; &#x0D;

Effect of Water Hardness on Catechin and Caffeine Content in Green Tea Infusions.

The health benefits of green tea are associated with its high catechin content. In scientific studies, green tea is often prepared with deionized water. However, casual consumers will simply use their local tap water, which differs in alkalinity and mineral content depending on the region. To assess the effect of water hardness on catechin and caffeine content, green tea infusions were prepared with synthetic freshwater in five different hardness levels, a sodium bicarbonate solution, a mineral salt solution, and deionized water. HPLC analysis was performed with a superficially porous pentafluorophenyl column. As water hardness increased, total catechin yield decreased. This was mostly due to the autoxidation of epigallocatechin (EGC) and epigallocatechin gallate (EGCG). Epicatechin (EC), epicatechin gallate (ECG), and caffeine showed greater chemical stability. Autoxidation was promoted by alkaline conditions and resulted in the browning of the green tea infusions. High levels of alkaline sodium bicarbonate found in hard water can render some tap waters unsuitable for green tea preparation.

Epigallocatechin Is Eliminated Faster From Plasma Than Epigallocatechin Gallate: Mathematical Modeling of Green Tea Catechin Metabolism in Healthy Adults

Abstract Objectives The predominant catechins [epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin (EC), epicatechin gallate (ECG)] in green tea extract (GTE) vary in bioactivity. Our objective was to develop a physiologically relevant mathematical model of catechin metabolism and assess their fractional catabolic rates relative to their structural attributes, which may influence their bioactivities. Methods Pharmacokinetic data were collected from healthy adults (n = 18; 27 ± 7 y; 22 ± 2 kg/m2) after oral intake of 0.5 g GTE (EGCG: 290 mg, EGC: 87 mg, EC: 39 mg, ECG: 28 mg) delivered in 3 gelatin-based confections. Participants maintained a low-polyphenol diet for 3 d prior to the trial. Concentrations of deconjugated catechins were measured by LC-MS in plasma and urine collected at timed intervals over 12 and 24 h, respectively. A multi-compartment model of catechin metabolism was developed using the mean fraction of dose for all catechins. Data were fitted by iterative least squares regression analysis in WinSAAM software. Kinetic parameters for EGCG and EGC were compared using a Student t-test and one-way ANOVA. Results Observed data for each catechin were successfully fit into a 7-compartment model comprised of the gastrointestinal tract (stomach, small and large intestine), liver, plasma, extravascular tissues, and kidneys. Goodness of fit was ascertained by the estimated variability of parameters (FSD &amp;lt; 0.5). Based on plasma response profiles, EGC and EC disappeared from plasma faster compared with EGCG and ECG. The highest fractional uptake was by the extravascular tissues (P &amp;lt; 0.05) with no other between-organ differences. Compared with EGCG, EGC showed a higher fractional transfer from the liver to plasma (2.5 vs. 0.4 pools/h, P &amp;lt; 0.001) and the uptake by kidneys (1.2 vs. 0.01 pools/h, P &amp;lt; 0.001) with no difference in absorption. The fractional catabolic rate was also higher for EGC compared with EGCG (59.4 vs. 42.7 plasma pools/h, P &amp;lt; 0.05), while its plasma transit time was shorter (0.9 vs. 1.3 min, P &amp;lt; 0.05). Conclusions A 7-compartment model, to be validated in a future study, was successfully developed to demonstrate that EGC is eliminated faster compared with EGCG in healthy adults, suggesting that the gallate group may influence relative bioactivity of catechins. Funding Sources The Ohio State University and the National Institute of Food and Agriculture.

SA incubation induced accumulation of flavan-3-ols through activated VvANR expression in grape leaves

Salicylic acid (SA) induces flavanol biosynthesis in grapes; however, the underlying molecular mechanisms remain largely unclear. Here, we showed that exogenous SA increases the content of flavan-3-ol, one of the main phenolics in grape leaves, by improving the activities of anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR) through induction of the expression of the VvANR, VvLAR1, VvLAR2 and VvMYBPA2 genes in grape leaves. Suppression of VvANR expression in TRV-VvANR-infected grape leaves using virus-induced gene silencing (VIGS) resulted in reduced expression of the VvANR, VvLAR1, VvMYBPA1 and VvMYBPA2 genes and a subsequent reduction in the enzyme activities of ANR and LAR and the contents of (-)-epicatechin (EC) and (-)-epigallocatechin (EGC). Supplementation with exogenous SA increased the contents of flavan-3-ol monomers, i.e., (+)-catechin, (-)-epicatechin and (-)-epigallocatechin, and improved ANR activity by upregulating the expression of VvLAR1, VvLAR2, VvMYBPA1 and VvMYBPA2 in TRV-VvANR-infected grape leaves. These results collectively suggested that the application of SA may represent a useful strategy for improving flavan-3-ol biosynthesis in grapes and that ANR plays a vital role in this process.

Effect of Acidified Ethanol on Antioxidant Properties of Morinda citrifolia Leaf Extract and Its Catechin Derivatives

This study was conducted to investigate the effect of ethanol acidification on the antioxidant properties of Morinda citrifolia leaf (MCL) extract and its catechin derivatives. Four different ethanol (100%, 99.5%, 70%, 50%) with or without 0.5% acetic acid were used for extraction. The antioxidant profile was studied with DPPH radical scavenging activity, FRAP and TPC. The quantification of catechins in MCL was performed using HPLC, and the identification of catechins derivatives was performed with Ultra UPLC-TWIMS-QTOF. The results showed that an extraction solvent composed of 70% ethanol: 29.5% water: 0.5 % acetic acid exhibited the highest DPPH percentage of inhibition (86.12±2.96%) and highest TPC value with 97.80±0.25 mg GAE/g extract, while 100% ethanol acidified with 0.5% acetic acid showed highest FRAP antioxidant power with 1.31±0.05mg FSE/g extract. All eight types of catechins were identified in MCL and the most total catechins were quantified in 70% ethanol: 29.5% water: 0.5 % acetic acid at 153.57mg/g. The catechin derivatives identified included epigallocatechin-3-O-gallate (EGCG), epigallocatechin (4β, 8)-gallocatechin, gallocatechin (4α→8)-epicatechin, catechin-3-O-gallate (CG) and epigallocatechin (EGC). The results suggest that acidification improves the extraction of polyphenols as well as catechin content.

Inhibitory mechanism of catechins against advanced glycation end products of glycated myofibrillar protein through anti-aggregation and anti-oxidation

Protein aggregation and oxidation could induce the generation of advanced glycation end products (AGEs). Nϵ-carboxymethyl lysine (CML), Nϵ-carboxyethyllysine (CEL) are two typical AGEs markers in muscle foods. Catechins are considered to be excellent natural antioxidants for scavenging AGEs in muscle protein. We compared, for the first time, the inhibitory effects and explored mechanisms of (−)-epigallocatechin (EGC), (−)-epigallocatechin-3-gallate (EGCG), (−)-epicatechin (EC), and (−)-epicatechin-3-gallate (ECG), in glycated myofibrillar protein (MPG) by measuring AGEs level, Maillard reaction degree, particle size and anti-oxidation ability using microstructure, multispectral and molecular docking techniques. The results showed that catechins dose-dependently inhibited AGEs in MPG through influencing lysine and free amino group, alleviating the Maillard reaction, detaching the particle size, affecting the protein-catechins interaction, relieving aggregates, and scavenging free radicals. The underlying mechanism behind the result indicated that catechins altered the structure information, SDS-PAGE bands, and the interaction sites of MPG via anti-aggregation and anti-oxidation. Particularly, EC and ECG showed weaker antioxidant ability than EGC and EGCG, EGCG exhibited a significant Pearson's correlation with the anti-oxidation and anti-aggregation of CML but no significant association with CEL. Overall, this study provides a theoretical insight into the applications of catechins to muscle foods as AGEs inhibitors.

Effect of non-covalent binding of phenolic derivatives with scallop (Patinopecten yessoensis) gonad protein isolates on protein structure and in vitro digestion characteristics

The present study was aimed to investigate the effects of non-covalent interactions between scallop gonad protein isolates (SGPIs) and different concentrations (20, 120 and 240 μmol/g, protein basis) of four phenolic compounds, such as (-)-epigallocatechin gallate (EGCG), epicatechin 3-gallate (ECG), epigallocatechin (EGC), and catechin (C), regarding the structural and functional properties of the complex. Total sulfhydryl and surface hydrophobicity in SGPIs decreased by nearly 72% and 65% with 240 μmol/g EGCG, similar but less appreciable changes were produced by EGC, ECG and C. Fluorescence quenching and thermodynamic parameters suggested that hydrogen bond and van der Waals dominated the interaction process between SGPIs and EGCG, and the interaction was further studied by molecular docking. Moreover, EGCG-treated SGPIs digests exerted higher ABTS+• scavenging activity than that of ECG and EGC-treated SGPIs. These findings are helpful to reveal the binding mechanism of phenolics and SGPIs, and provide a theoretical basis for the application of SGPIs-phenolic complexes as functional food additives.

A Review on the Biological Activity of Camellia Species.

Medicinal plants have been used since antiquity to cure illnesses and injuries. In the last few decades, natural compounds extracted from plants have garnered the attention of scientists and the Camellia species are no exception. Several species and cultivars are widespread in Asia, namely in China, Japan, Vietnam and India, being also identified in western countries like Portugal. Tea and oil are the most valuable and appreciated Camellia subproducts extracted from Camellia sinensis and Camellia oleifera, respectively. The economic impact of these species has boosted the search for additional information about the Camellia genus. Many studies can be found in the literature reporting the health benefits of several Camellia species, namely C. sinensis, C. oleifera and Camellia japonica. These species have been highlighted as possessing antimicrobial (antibacterial, antifungal, antiviral) and antitumoral activity and as being a huge source of polyphenols such as the catechins. Particularly, epicatechin (EC), epigallocatechin (EGC), epicatechin-3-gallate (ECG), and specially epigallocatechin-3-gallate (EGCG), the major polyphenols of green tea. This paper presents a detailed review of Camellia species’ antioxidant properties and biological activity.

Comprehensive evaluation of 47 tea [Camellia sinensis (L.) O. Kuntze] germplasm based on entropy weight method and grey relational degree

China has the most abundant tea resources in the world. In oder to scrutinize superior accessions suitable for popularization and planting, the quality characteristics of distinctive tea resources were analyzed by examining their key evaluation indexes and comprehensive evaluation methods. In this study, 29 indexes of 47 tea germplasms were detected, including agronomic characters, chemical compositions, quality of green tea and stress resistance. The key evaluation indexes were selected by factor analysis and cluster analysis, whereas the weight value of the indexes was determined by analytic hierarchy process (AHP) and entropy weight method. Furthermore, the comprehensive evaluation of tea varieties was carried out by grey correlation degree and entropy weight method. Our results showed that drastic differences of character indexes existed among tea varieties, and the 29 character indexes demonstrated complex information overlapping with each other. After simplification, 12 key evaluation indexes, namely score of green tea quality, total free amino acids, growth potential, water extract, yield, epigallocatechin gallate (EGCG), epigallocatechin (EGC), one bud one leaf stage, insect resistance, germination density, bud leaf color, and gallic acid (GA) were chosen. The weight value of each index was also determined. Since the rank of some varieties in these two evaluation methods was different, based on the comprehensive evaluation results of grey correlation degree method and entropy weight method, it was more rational to combine these two evaluation methods in selecting superior varieties. Consequently, nine excellent tea varieties were selected. This study not only provides an innovative method for comprehensive evaluation of tea resources, but also an approach to promote genetic improvement of the selected excellent tea varieties.

Calculation study on complex formation of catechins with β-cyclodextrin using density function theory

The inclusion of catechins with cyclodextrin (CD) is performed for the purpose of improving the water solubility and reducing the bitterness of catechins. In this study, the effect of catechins’ conformation on the formation of an inclusion complex between catechins and β-CD was examined by density functional theory (DFT) calculation at the B3PW91/cc-pVDZ level. It is known that the main components of catechins in tea leaves are (−)-epigallocatechin (EGC), which is a non-gallate-type catechin, and (−)-epigallocatechin gallate (EGCg), which is a gallate-type catechin. Catechins have a plurality of sites that can be included by β-CD (EGC: AC ring and B ring, EGCg: AC ring, B ring, and B′ ring). First, initial models for the calculation in which each ring of catechins gradually approaches into the cavity of β-CD were built. These initial models were optimized in water and then the optimized structure of the inclusion complex in water was determined. From the results of calculation, the degree of penetration of each ring into the β-CD cavity, the complex formation energy, and the number of intermolecular hydrogen bonds were examined. The results of calculation showed that the AC ring of catechins is most deeply included in the β-CD cavity and the B′ ring of catechins forms an energetically stable complex with β-CD. It was found that the inclusion complex of catechins and β-CD is stabilized energetically by intermolecular hydrogen bonds.

The roles of sucrose on the retronasal thresholds of tea catechins and polyphenols in water‐based system

AbstractThe objective of this study was to determine the role of sucrose in the retronasal detection thresholds of caffeine, theobromine, and tea catechins, including epicatechin gallate (ECG), epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallic acid (GA), and gallocatechin gallate (GCG), in a water‐based system. The detection threshold tests were conducted using standard practice for determination of taste thresholds by a forced choice ascending concentration series method of limits in ASTM E679‐05 on different water‐based matrices with varying degrees of sucrose levels. The Best Estimate Thresholds (BET) of caffeine, theobromine, ECG, EGC, EGCG, and GCG in water were 73.88, 70.83, 47.58, 40.03, 61.91, and 29.06 mg/kg, respectively. An increase in BETs was observed with an increased level of sucrose in the water‐based model for caffeine, and each of the catechins except theobromine and gallic acid. This result suggests a possible gallic acid‐sucrose interaction. This study reported the increase of detection threshold of bitter and astringency‐causing compounds with addition of sucrose in water‐base model system. This can provide another perspective of using sucrose to mask bitterness and astringency in coffee and tea products.Practical applicationsConsumption of coffee and tea has been increasing worldwide. Catechins and caffeine are the chemical compounds that give bitterness and astringency in green tea and coffee products, making consumers avoid these products. Reduction of bitterness and astringency in coffee and green tea products is crucial to expand the market. The outcome of this study indicated an increase in BETs with an increased level of sucrose in the water‐based model for caffeine, and each of the catechins except theobromine and gallic acid. This means that addition of sugar can help reducing bitterness and astringency perception by increasing individual threshold of such compound. Findings from this study can contribute beverage industry to reformulating their beverage products more appealing to their target consumers.

Apomorphine Targets the Pleiotropic Bacterial Regulator Hfq.

Hfq is a bacterial regulator with key roles in gene expression. The protein notably regulates translation efficiency and RNA decay in Gram-negative bacteria, thanks to its binding to small regulatory noncoding RNAs. This property is of primary importance for bacterial adaptation and survival in hosts. Small RNAs and Hfq are, for instance, involved in the response to antibiotics. Previous work has shown that the E. coli Hfq C-terminal region (Hfq-CTR) self-assembles into an amyloid structure. It was also demonstrated that the green tea compound EpiGallo Catechin Gallate (EGCG) binds to Hfq-CTR amyloid fibrils and remodels them into nonamyloid structures. Thus, compounds that target the amyloid region of Hfq may be used as antibacterial agents. Here, we show that another compound that inhibits amyloid formation, apomorphine, may also serve as a new antibacterial. Our results provide an alternative in order to repurpose apomorphine, commonly used in the treatment of Parkinson’s disease, as an antibiotic to block bacterial adaptation to treat infections.

Extraction and Estimation of Different Active Constituents present in the different brands of Green Tea by using Analytical Methods

Green tea (camellia sinensis. L) is one of the most popular highly used in nutritional supplement in the world. Ethanol and water were used as a solvent to extract active constituents from different brand of green tea like Lipton, Tetley, and Ecovalley natural green tea. The active constituents of green tea can be determined by analytical instruments like IR spectrophotometer used to know functional groups and TLC technique is used to know purity and no of different constituents of different brands of green tea. The absorbances can be determined by Colorimetry and UV spectroscopy, The DSC can be used to know the melting point of different constituents of different brands of green tea. The antioxidants present in the different brands of green tea estimated by using DPPH method. Predict the Immune booster activity of-(-) epigallo catechin gallate (EGCG) with target protein 3NG5 by docking study using the software swiss docking. By the above analytical methods, Ethanolic extract shows high percentage of yield than hot water extraction. Lipton green tea brand shows more active constituents compared to other brands of green tea.

Emulsification of Scutellaria baicalensis Georgi polysaccharide conjugate and its inhibition on epigallocatechin (EGC) oxidation

The oil-in-water (O/W) emulsions were prepared from Scutellaria baicalensis polysaccharide conjugates (SBPC) as an emulsifier and medium-chain triglyceride (MCT). Effects of pH, metal ions and heat treatment on the emulsion stability were investigated. Compared to that of 0.20 ̶ 1.00 wt% SBPC and 2.00 wt% GA, 2.00 wt% and 3.00 wt% SBPC stabilized emulsion droplets had a smaller particle size and were more stable during 10-day storage at 25 °C. The average particle sizes (d32) of emulsions containing metal ions varied from 4.54 to 6.62 μm (0.100–0.500 mol/L Na+), from 2.63 to 3.86 μm (0.010–0.050 mol/L Ca2+), and from 2.66 to 7.89 μm (0.001–0.030 mol/L Al3+), as well as the zeta potential varying from −17.63 to −19.67 mV (Na+), from −16.50 to −18.13 mV (Ca2+) and from −15.02 to −18.56 mV (Al3+). SBPC emulsion possessed stability under pH 3.0–7.0 and thermal treatment at 70–100 °C during the 10-day storage period. Furthermore, SBPC emulsion inhibited oxidative polymerization of EGC. The average retention rate of EGC was 88.28% on the 10th day. This research provides a new way for development and application of SBPC as an emulsifier.

Modulatory role of tea in arsenic induced epigenetic alterations in carcinogenesis

Epigenetic alterations, broadly divided into DNA methylation, Histone modifications and interference by non-coding RNAs can often lead to carcinogenesis. Alterations in epigenetic machinery may be due to numerous factors, including exposure to toxic chemicals. These toxicants include heavy metals as well. The metalloid arsenic is an environmental pollutant and its chronic exposure causes cancer. Etiology of arsenic induced cancer includes epigenetic alterations, among others. Inorganic-arsenic is the lead cause of hypermethylation of tumor-suppressor genes and hypomethylation of genes involved in cell proliferation, growth and invasion. It can induce histone methylations and acetylations along with modulation of miRNAs, promoting cancer. Therefore, control of epigenetic alterations is vital. Chemoprevention using phytochemicals is an effective strategy to mitigate the deleterious effect of chronic arsenic exposure. Flavonoids, a group of phytochemicals have shown numerous evidences of epigenetic modulations halting carcinogenesis. Catechins represent one of the most active groups of flavonoids. Tea, a popular beverage, is one of the richest sources of catechins. Green tea contains highly active catechins like epigallocatechin-3-gallate (EGCG), epigallocatechin (EGC), epicatechingallate (ECG) etc. while black tea contains oxidized polymeric catechins like theaflavin and thearubigin. Green tea catechins have elicited their potential as an epigenetic modulator, establishing their chemopreventive attributes. Therefore, administration of tea may be an effective strategy to mitigate the epigenetic alterations, induced by chronic exposure to arsenic, in individuals of endemic areas.

Chocolate as a food matrix reduces the bioavailability of galloylated catechins from green tea in healthy women.

In this study, we evaluated the food matrix effects of chocolate on the absorption of green tea catechins (GTCs), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg), and (-)-epigallocatechin gallate (EGCg), in five healthy 22-year-old women. In the single-intake experiment, the plasma concentrations of ECg (P < 0.05, at 1.5 h) and EGCg (P < 0.05, at 6 h) but not those of EC and EGC were reduced by the chocolate matrix. Regardless of the chocolate matrix, ECg and EGCg were mainly present as their aglycones in the plasma, whereas EGC and EC were found mostly as conjugated metabolites. After daily intake of GTCs mixed with chocolate for 14 days followed by overnight fasting, ECg but not EGCg was detected in the plasma. To compare the plasma profiles of ECg and EGCg, a mixture containing approximately equal amounts of ECg and EGCg was administered to nine rats for 14 days. Following treatment and overnight food deprivation, the plasma content of ECg was higher than that of EGCg. After a single injection of the same mixture in seven rats, ECg levels were higher than those of EGCg, and a greater amount of conjugated metabolites of ECg than those of EGCg was detected in the plasma 10 h after administration. In conclusion, the chocolate matrix affects the plasma profiles of GTCs, particularly ECg. ECg appears to persist in the plasma for a longer period, regardless of the chocolate matrix.