Especially Epigallocatechin Gallate Research Articles

The influence of green tea extract on nintedanib’s bioavailability in patients with pulmonary fibrosis

Nintedanib is an oral small-molecule kinase inhibitor and first-line treatment for idiopathic pulmonary fibrosis. Nintedanib is a substrate of the drug efflux transporter ABCB1. Green tea flavonoids --especially epigallocatechin gallate (EGCG)-- are potent ABCB1 modulators. We investigated if concomitant administration of green tea extract (GTE) could result in a clinically relevant herb-drug interaction.Patients were randomized between A-B and B-A, with A being nintedanib alone and B nintedanib with GTE. Both periods lasted 7 days, in which nintedanib was administered twice daily directly after a meal. In period B, patients additionally received capsules with GTE (500 mg BID, >60% EGCG). Pharmacokinetic sampling for 12 h was performed at day 7 of each period. Primary endpoint was change in geometric mean for the area under the curve (AUC0–12 h). A linear mixed model was used to analyse AUCs and maximal concentration (Cmax).In 26 included patients, the nintedanib AUC0–12 h was 21% lower (95% CI −29% to −12%; P < 0.001) in period B (with GTE) compared to period A. Cmax did not differ significantly between periods; − 14% (95% CI −29% to +4%; P = 0.12). The detrimental effect was predominant in patients with the ABCB1 3435 C>T wild type variant. No differences in toxicities were observed.Exposure to nintedanib decreased with 21% when administered 60 min after GTC for only 7 days. This is a statistically significant interaction which could potentially impair treatment efficacy. Before patients and physicians should definitely be warned to avoid this combination, prospective clinical validation of an exposure-response relationship is necessary.

New insights into the role of the Nrf2 signaling pathway in green tea catechin applications

Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a transcriptional signaling pathway that plays a crucial role in numerous clinical complications. Pivotal roles of Nrf2 have been proved in cancer, autoimmune diseases, neurodegeneration, cardiovascular diseases, diabetes mellitus, renal injuries, respiratory conditions, gastrointestinal disturbances, and general disorders related to oxidative stress, inflammation, apoptosis, gelatinolysis, autophagy, and fibrogenesis processes. Green tea catechins as a rich source of phenolic compounds can deal with various clinical problems and manifestations. In this review, we attempted to focus on intervention between green tea catechins and Nrf2. Green tea catechins especially epigallocatechin gallate (EGCG) elucidated the protective role of Nrf2 and its downstream molecules in various disorders through Keap-1, HO-1, NQO-1, GPx, GCLc, GCLm, NF-kB cross-link, kinases, and apoptotic proteins. Subsequently, we compiled an updated expansions of the Nrf2 role as a gate to manage and protect different disorders and feasible indications of green tea catechins through this signaling pathway. The present review highlighted recent evidence-based data in silico, in vitro, and in vivo studies on an outline for future clinical trials.

Zielona herbata a otyłość – wpływ katechin na metabolizm energetyczny

Streszczenie Otyłość jest chorobą metaboliczną, która obecnie zyskała rangę epidemii, stanowiąc jeden z najważniejszych problemów zdrowotnych, społecznych i ekonomicznych na świecie. Nieleczonej otyłości towarzyszy pogorszenie jakości życia oraz występowanie chorób towarzyszących, takich jak cukrzyca czy schorzenia układu sercowo-naczyniowego. W związku z tym poszukuje się nowych metod mających zastosowanie zarówno w profilaktyce otyłości, jak i w obniżaniu nadmiernej masy ciała. Zawarte w zielonej herbacie związki katechinowe, szczególnie galusan epigallokatechiny (EGCG), są jednymi z najintensywniej badanych substancji biologicznie czynnych. Przypisuje się im właściwości przeciwutleniające, przeciwzapalne, przeciwnowotworowe, a także wspomagające regulację masy ciała oraz zawartości tkanki tłuszczowej w organizmie. Liczne badania z udziałem ludzi wykazują, że regularne picie zielonej herbaty jest związane z mniejszą masą ciała, niższym BMI oraz z mniejszym obwodem pasa. Wyniki doświadczeń in vitro oraz na zwierzętach potwierdzają korzystny wpływ katechin na metabolizm energetyczny. Związki te obniżają wchłanianie lipidów i węglowodanów w przewodzie pokarmowym. Wpływają również na metabolizm tych związków, obniżając intensywność lipogenezy i adipogenezy, jednocześnie pobudzając lipolizę i utlenianie kwasów tłuszczowych, a także zwiększając wydatek energetyczny. Udowodniono, że katechiny mają wpływ na wychwyt glukozy przez komórki docelowe pobierające ten cukier poprzez insulinozależny transporter – GLUT4. W artykule omówiono literaturę przedmiotu oraz usystematyzowano zagadnienia związane z rolą katechin obecnych w zielonej herbacie w profilaktyce i wspomaganiu leczenia otyłości.

Proanthocyanidin-Aluminum Complexes Improve Aluminum Resistance and Detoxification of Camellia sinensis.

Aluminum (Al) influences crop yield in acidic soil. The tea plant (Camellia sinensis) has high Al tolerance with abundant monomeric catechins in its leaves, especially epigallocatechin gallate (EGCG), and polymeric proanthocyanidins in its roots (rPA). The role of these polyphenols in the Al resistance of tea plants is unclear. In this study, we observed that these polyphenols could form complexes with Al in vitro, and complexation capacity was positively influenced by high solution pH (pH 5.8), polyphenol type (rPA and EGCG), and high Al concentration. In the 27Al nuclear magnetic resonance (NMR) experiment, rPA-Al and EGCG-Al complex signals could be detected both in vitro and in vivo. The rPA-Al and EGCG-Al complexes were detected in roots and old leaves, respectively, of both greenhouse seedlings and tea garden plants. Furthermore, in seedlings, Al accumulated in roots and old leaves and mostly existed in the apoplast in binding form. These results indicate that the formation of complexes with tea polyphenols in vivo plays a vital role in Al resistance in the tea plant.

Preparation of Strong Antioxidative, Therapeutic Nanoparticles Based on Amino Acid-Induced Ultrafast Assembly of Tea Polyphenols.

Nanoformulations offer the opportunity to overcome the shortcomings of drug molecules, such as low solubility, side effects, insufficient stability, etc., but in most of the current nanomedicines, nanocarriers as excipients do not directly participate in the therapy procedure. Accordingly, it is promising to develop the nanotherapeutics composed entirely of pharmaceutically active molecules. Tea polyphenols, especially epigallocatechin gallate (EGCG), are a kind of natural antioxidants with various biological and health beneficial effects and are extensively investigated as nutrients and anticancer drugs. Here, the size-tunable and highly active polyphenol nanoparticles were conveniently synthesized in water and could be massively produced with a simple facility. Compared to the previous strategies, either molecular assembly via oxidative coupling or combination with other biomacromolecules, the present preparation was conducted by the amino acid-triggered Mannish condensation reactions, thus permitting the flexible molecular design of various polyphenol nanoparticles by selecting different amino acids. This straightforward and ultrafast method actually opens up a novel means to make use of naturally reproducible polyphenols. Moreover, inheriting the salient properties of EGCG, these nanoparticles show strong antioxidation capacity, 10-fold higher than the extensively investigated polydopamine nanoparticles, and they are biosafe but have therapeutic effects, according to the in vitro and in vivo assessments of anticancer activity, which is promising for various biomedical purposes.

Quantification of ascorbyl adducts of epigallocatechin gallate and gallocatechin gallate in bottled tea beverages

Catechins are the major bioactive compounds existing in tea leaves (Camellia sinensis). Dehydroascorbic acid is (DHAA) a reactive dicarbonyl species and previous studies have demonstrated that catechins could effectively trap DHAA to form ascorbyl adducts of catechins, especially epigallocatechin gallate (EGCG). Since catechins in the aqueous solution are unstable due to their structural features, ascorbic acid (AA) is usually added to bottled tea beverages to protect catechins. However, whether ascorbyl adducts of catechins are formed in bottled tea beverages remains unclear. In this study, formation of ascorbyl adducts of EGCG increased along with increased incubation time when EGCG and AA were dissolved in the aqueous solution. Next, 6C-DHAA-EGCG and 8C-DHAA-EGCG were detected in both green tea and oolong tea beverages, and their concentrations ranged from 0.23 to 1.95 µM and 0.28 to 1.97 µM, respectively. Furthermore, an 8C-ascorbyl adduct derived from gallocatechin gallate was also found in some tea beverages.

Effect of Diabetea tea ™ consumption on inflammatory cytokines and metabolic biomarkers in type 2 diabetes patients

Ethnopharmacological relevanceDiabetea tea™ (DT) is an anti-diabetic alternative medicine in some Asian countries. The main constituent of DT is black tea originating from Camellia sinensis that is supplemented by 12 other medicinal plants. Black tea contains a large amount of the flavonoids catechins especially epigallocatechin gallate (EGCG) which has anti-inflammatory and antioxidative capacity. This study was undertaken to evaluate the possible effects of DT intake on inflammatory cytokines, regulatory T cells (Tregs) and metabolic biomarkers in T2DM. Materials and methodsThe study included 50 patients with T2DM. The patients had received 3 cups (600ml) of DT extract or placebo (PL) extract per day during a period of 12 weeks. Intracellular cytokine expression in peripheral blood mononuclear cell (PBMC) as well as the glycemic and lipid profiles were measured at baseline and after the treatment period. The active constituents of the medicinal plants included in DT were investigated by gas chromatography-mass spectrometry (GC/MS). ResultsIngestion of DT suppressed CD4+ T cell expression of IL-1β and Il-8 (p<0.05) and up-regulated the expression of IL-10 and the Treg/IL-17 ratio (p<0.05) which was not shown in PL. A significant decrease in HbA1c and LDL was observed at the end of the study period (p<0.05) in DT. The GC/MS analyses of DT indicated the presence of lupeol, β-Amyrin and β-sitosterol. Also analyses of individual herbs showed the presence of higher levels of lupeol and β-Amyrin in Nuga Ficus bengalensis and β-sitosterol in the Attikka Ficus racemosa, indicating that the active ingredients of DT are concentrated in these two herbs. ConclusionThe present study provides evidence that DT has hypoglycemic and antihyperlipidemic properties. Interestingly, DT has anti-inflammatory effects. These properties are attributed to the flavonoids, triterpenes and phytosterol contents of the tea. We suggest that DT protects against diabetes complications in the long term.

Epigallocatechin Gallate Inhibits Biofilm Production and Attenuates Virulent Factors of Pseudomonas aeruginosa and Psuedomonas fluorescence

Catechins especially Epigallocatechin Gallate (EGCG) and its isomers have been shown to constitute the most important and effective antimicrobial part of tea polyphenols. Antimicrobial effects of EGCG on a variety of pathogens have been published previously. The anti-microbial mechanism of green tea polyphenols has also been studied. Effects of green tea extracts on bacterial surviving tactics such as Quorum Sensing (QS) have showed significant inhibitory effects. However, there are no literatures that demonstrate a quantitative assay that would establish the Minimum Inhibitory Concentration (MIC) that can interfere with QS regulated factors. Also, there is no published data that clearly demonstrates which components of green tea or black tea is responsible for the inhibition of QS-regulated virulence factors. In this study we prove that EGCG which constitutes 5% of dry weight of green tea and 10% in green tea is effective in inhibiting the biofilm production of Psuedomonas aeruginosa and Psuedomonas fluorescens by down-regulating its virulence factors. Our study established a Minimum Inhibitory Concentration (MIC) of 8mM (∼4 mg/ml) concentration of EGCG for inhibition of biofilm production in both organisms. QS regulated virulent factors such as pyocyanin, protease and elastase production also decreased with increase in the EGCG concentration.

Rapid tea catechins and caffeine determination by HPLC using microwave-assisted extraction and silica monolithic column

A rapid reversed-phase high performance liquid chromatographic method using a monolithic column for the determination of eight catechin monomers and caffeine was developed. Using a mobile phase of water:acetonitrile:methanol (83:6:11) at a flow rate of 1.4mLmin−1, the catechins and caffeine were isocratically separated in about 7min. The limits of detection and quantification were in the range of 0.11–0.29 and 0.33–0.87mgL−1, respectively. Satisfactory recoveries were obtained (94.2–105.2±1.8%) for all samples when spiked at three concentrations (5, 40 and 70mgL−1). In combination with microwave-assisted extraction (MAE), the method was applied to the determination of the catechins and caffeine in eleven tea samples (6 green, 3 black and 2 oolong teas). Relatively high levels of caffeine were found in black tea, but higher levels of the catechins, especially epigallocatechin gallate (EGCG) were found in green teas.

Beneficial effects of green tea catechin on massive hepatectomy model in rats

Green tea catechin, especially epigallocatechin gallate (EGCG), is a well-known scavenger of reactive oxygen species and it may also function as an antioxidant through modulation of transcriptional factors and enzyme activities. Green tea extract (GTE®) which contained numerous EGCG was used. Wistar rats were performed 90 % hepatectomy and classified into 2 groups with (GTEHx, n = 25) or without GTE treatment (Hx, n = 25) and sacrificed at 1, 3, 7 and 14 days after operations. All rats had free access to drinking water supplemented with or without GTE from the 7th pre-operative day. Liver regeneration, hepatic inducible nitric oxide synthase (iNOS), anti-oxidative enzymes [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px)] and inflammatory markers [cyclooxygenase-2 (COX-2), nuclear factor kappa B (NFκB), tumor necrosis factor-α (TNF-α)] were investigated. The liver weight to body weight ratio (p < 0.01), proliferating cell nuclear antigen labeling index (p < 0.05) and phosphorylated extracellular signal-regulated kinase 1/2 (p < 0.05) at day 1 in the GTEHx group significantly increased compared to the Hx group. Hepatic iNOS levels at day 1 significantly decreased (p < 0.01) in the GTEHx group. Hepatic SOD, CAT and GSH-Px levels at day 1 significantly increased (SOD: p < 0.01, CAT and GSH-Px: p < 0.05) in the GTEHx group. In contrast, COX-2, NFκB and TNF-α levels at day 1 significantly decreased (COX-2: p < 0.01, NFκB and TNF-α: p < 0.05) in the GTEHx group. GTE pretreatment stimulated liver regeneration and improved liver damage after massive hepatectomy through anti-oxidative and anti-inflammatory effects. Green tea catechin might have the potential to attenuate liver dysfunction in early stage after massive hepatectomy.

Tea catechin epigallocatechin gallate inhibits Streptococcus mutans biofilm formation by suppressing gtf genes

ObjectiveThe anti-cariogenic properties of tea have been suggested for decades. Tea polyphenols, especially epigallocatechin gallate (EGCG), have been shown to inhibit dental plaque accumulation, but the exact mechanisms are not clear at present. We hypothesise that EGCG suppresses gtf genes in Streptococcus mutans at the transcriptional level disrupting the initial attachment of S. mutans and thus the formation of mature biofilms. DesignIn this study, the effect of EGCG on the sucrose-dependent initial attachment of S. mutans UA159 in a chemically defined medium was monitored over 4h using a chamber slide model. The effects of EGCG on the aggregation and gtf B, C, D gene expression of S. mutans UA159 were also examined. ResultsIt was found that EGCG (7.8–31.25μg/ml) exhibited dose-dependent inhibition of the initial attachment of S. mutans UA159. EGCG did not induce cellular aggregation of S. mutans UA159 at concentrations less than 78.125μg/ml. Analysis of data obtained from real-time PCR showed that EGCG at sub-MIC level (15.6μg/ml) significantly suppressed the gtf B, C, D genes of S. mutans UA159 compared with the non-treated control (p<0.05). ConclusionsThese findings suggest that EGCG may represent a novel, natural anti-plaque agent that inhibits the specific genes associated with bacterial biofilm formation without necessarily affecting the growth of oral bacteria.

The Tea Catechin Epigallocatechin Gallate Suppresses Cariogenic Virulence Factors of Streptococcus mutans

Streptococcus mutans, the primary etiologic agent of dental caries, possesses a series of virulence factors associated with its cariogenicity. Alternatives to traditional antimicrobial treatment, agents selectively inhibiting the virulence factors without necessarily suppressing the resident oral species, are promising. The anticariogenic properties of tea have been suggested in experimental animals and humans. Tea polyphenols, especially epigallocatechin gallate (EGCg), have been shown to inhibit the growth and glucosyltransferases activity of S. mutans. However, their effects on biofilm and cariogenic virulence factors of oral streptococci other than glucosyltransferases have not been well documented. In this study, we investigated the biological effect of EGCg on the virulence factors of S. mutans associated with its acidogenicity and acidurity. The antimicrobial effects of EGCg on S. mutans biofilm grown in chemically defined medium were also examined. EGCg inhibited growth of S. mutans planktonic cells at an MIC of 31.25 μg/ml and a minimal bactericidal concentration (MBC) of 62.5 μg/ml. EGCg also inhibited S. mutans biofilm formation at 15.6 μg/ml (minimum concentration that showed at least 90% inhibition of biofilm formation) and reduced viability of the preformed biofilm at 625 μg/ml (sessile MIC₈₀). EGCg at sub-MIC levels inhibited acidogenicity and acidurity of S. mutans cells. Analysis of the data obtained from real-time PCR showed that EGCg significantly suppressed the ldh, eno, atpD, and aguD genes of S. mutans UA159. Inhibition of the enzymatic activity of F₁F₀-ATPase and lactate dehydrogenase was also noted (50% inhibitory concentration between 15.6 and 31.25 μg/ml). These findings suggest that EGCg is a natural anticariogenic agent in that it exhibits antimicrobial activity against S. mutans and suppresses the specific virulence factors associated with its cariogenicity.

(−) Epigallocatechin gallate suppresses the differentiation of 3T3-L1 preadipocytes through transcription factors FoxO1 and SREBP1c

Tea catechin is one of the compounds that are closely related to obesity and insulin sensitivity. In order to determine the effect of catechin on adipocyte differentiation, we treated 3T3-L1 preadipocytes with different kinds of catechins. Our results showed that catechins, especially epigallocatechin gallate (EGCG), significantly reduced intracellular lipid accumulation and repressed the activity of glycerol-3-phosphate dehydrogenase, an enzyme involved in lipid synthesis. Furthermore, glucose and fatty acid transport were also suppressed by catechin. We then analyzed the activity of transcription factors-forkhead transcription factor class O1 (FoxO1) and sterol regulatory element-binding protein-1c (SREBP1c)-which are involved in adipocyte differentiation and lipid synthesis, respectively. The transcriptional activities of both these factors significantly decreased by EGCG. Western blot analysis revealed that EGCG induced the insulin signal-mediated phosphorylation of FoxO1 (Thr24, Ser256). These results suggest that EGCG suppresses the differentiation of adipocytes through the inactivation of FoxO1 and SREBP1c.

Abstract A95: Epigenetic changes in colon cancer cell lines treated with the green tea polyphenolic, EGCG

Abstract Retinoids are known for their role in regulating cell growth and proliferation and for activating tumor suppressor genes. We have previously shown that Retinoid X Receptor alpha (RXRα) is silenced in tumors of the colon cancer AOM-APCMin/+ mouse model. Upon treatment with green tea, RXR expression was restored and intestinal tumorigenesis was inhibited. We hypothesize that tea polyphenols, especially epigallocatechin gallate (EGCG), induce modification of gene expression through effects of DNA methyltransferases (DNMTs) as well as Histone Deacetylases (HDACs). We treated HT-29 and HCT116 colon cancer cells with EGCG concentrations of 0, 50, 100 or 150µM or 5µM of the DNMT inhibitor 5-aza-2dC for 48, 72 and 96 hours as well as for two, three and four doubling times. The cell lines were chosen based on their methylation status. HCT116 cells are more sensitive to promoter region methylation compared to HT-29 cells. Using nuclear fractions of the cell lysates, we probed for presence of the most common DNMTs and HDACs using western blotting. We found that expression of DNMTs as well as HDACs was inhibited in a dose dependent manner following treatment with EGCG. We also found that treatments according to doubling times showed a more profound difference in expression levels when compared to traditional time points. We can conclude that the silencing of RXRα may be due in part to by repressing effects of EGCG on DNMT as well as HDAC activity. This could be one potential mechanism of cancer chemoprevention in green tea that outlines a new epigenetic pathway. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A95.

Abstract A54: Epigenetic changes in colon cancer cell lines treated with the tea polyphenolic, EGCG

Abstract A54 Retinoids are known for their role in regulating cell growth and proliferation and for activating tumor suppressor genes. We have previously shown that Retinoid X Receptor alpha (RXR alpha) is silenced in tumors of the colon cancer AOM-APCmin+ mouse model. Upon treatment with green tea, RXR alpha expression was restored and intestinal tumorigenesis was inhibited. We hypothesize that tea polyphenols, especially epigallocatechin gallate (EGCG), induce modification of gene expression through effects of DNA methyltransferases (DNMTs). We first determined the optimal range of EGCG concentration with which to treat the cells by performing cytotoxcity assays. We treated HT-29 and HCT116 colon cancer cells with EGCG concentrations of 0, 50, 100 or 150µM for 24 and 48 hours. The cell lines were chosen based on their methylation status. HCT116 cells are sensitive to methylation while HT-29 cells are not. Using nuclear fractions of the cell lysates, we probed for presence of the most common DNMTs using western blotting. We found that expression of DNMT1, DNMT3a and DNMT3b was inhibited in a dose dependent manner following treatment with EGCG at both 24 and 48 hour time points. We also used the DNMT inhibitor 5-aza-2dC as a positive control to recover DNMT expression in the cells treated with EGCG. We can conclude that the silencing of RXR alpha may be due in part to by repressing effects of EGCG on DNMT activity. Citation Information: Cancer Prev Res 2008;1(7 Suppl):A54.

Mechanisms and Effects of Green Tea on Cardiovascular Health

Green tea, rich in antioxidant and anti-inflammatory catechins, especially epigallocatechin gallate (EGCG), has been shown to reduce surrogate markers of atherosclerosis and lipid peroxidation, particularly LDL oxidation and malondialdehyde concentrations, in several in vitro, animal, and limited clinical studies. Epidemiological observations in Southeast Asian countries indicate an inverse correlation exists between habitual consumption of green tea beverages and the incidence of cardiovascular events. A few short-term clinical studies have reported its effects in attenuating biomarkers of oxidative stress and inflammation among smokers, and an ability to decrease postprandial lipemia in hypercholesterolemic subjects has also been suggested. However, further investigations are needed to confirm the potential role of green tea beverages and the safety of green tea supplements in reducing body fat, as well as other biomarkers of cardiovascular disease risks.

In vitro antioxidant and anticancer activities of ethanolic extract of selenium-enriched green tea

Selenium-enriched green tea is now being increasingly produced in China and is well known as a bioactive beverage, due to its high content of active components. In this study, the antioxidant and anticancer activities of an ethanolic extract and an aqueous extract of Se-enriched green tea were investigated. The results indicated that the ethanolic extract possessed significantly higher antioxidant activity than the aqueous extract and the positive control α-tocopherol, by both α,α-diphenyl-β-picrylhydrazyl (DPPH) radical-scavenging and ferric thiocyanate (FTC) assays. The ethanolic extract inhibited the proliferation of human cervical adenocarcinoma HeLa cell and possessed a significantly higher antitumour activity than the aqueous extract and the positive control 5-fluorouracil (5-FU), in the dose range of 62.5–250 μg/ml. Moreover, the ethanolic extract could significantly inhibit the growth of lung carcinoma A549 and hepatoma HepG2 in a concentration-dependent manner, with IC 50 values of 278.6 μg/ml and 431.6 μg/ml, respectively. Selenium, tea polyphenols and polyphenols constituents, especially epigallocatechin gallate (EGCG), were significantly higher in the ethanolic extract than in the aqueous extract, which were possibly responsible for the higher antioxidant and antitumour activities of the ethanolic extract.

Influence of epigallocatechin gallate and phenolic compounds from green tea on the growth of Oenococcus oeni

To investigate the effect of phenolic compounds on the growth of Oenococcus oeni. Oenococci are usually grown in media often supplemented with complex additives such as tomato juice. In order to improve our knowledge about the growth requirements of oenococci, we added several juices and leaf extracts such as green tea to the culture media and screened them for growth-stimulating substances to substitute complex supplements such as juices by more defined components. We found that also green tea could cause a growth stimulation of Oenococcus oeni strain B2. Further experiments showed that the stimulating effect was as a result of the phenolic compounds of green tea, especially epigallocatechin gallate (EGCG). On the other hand, EGCG could also inhibit the growth of O. oeni strain B2 just depending on its concentration. Individual catechins should have a minor influence on the growth of oenococci during wine making as their concentration in grapes is <30 mg kg(-1) grape. Whether there is a synergistic effect of the different catechins in wine has to be investigated.

Mechanisms and Effects of Green Tea on Cardiovascular Health

Green tea, rich in antioxidant and anti-inflammatory catechins, especially epigallocatechin gallate (EGCG), has been shown to reduce surrogate markers of atherosclerosis and lipid peroxidation, particularly LDL oxidation and malondialdehyde concentrations, in several in vitro, animal, and limited clinical studies. Epidemiological observations in Southeast Asian countries indicate an inverse correlation exists between habitual consumption of green tea beverages and the incidence of cardiovascular events. A few short-term clinical studies have reported its effects in attenuating biomarkers of oxidative stress and inflammation among smokers, and an ability to decrease postprandial lipemia in hypercholesterolemic subjects has also been suggested. However, further investigations are needed to confirm the potential role of green tea beverages and the safety of green tea supplements in reducing body fat, as well as other biomarkers of cardiovascular disease risks.

Epigallocatechin gallate induces apoptosis of monocytes

Monocytes are the main effector cells of the immune system, and the regulation of their survival and apoptosis is essential for monocyte-involved immune responses. Green tea polyphenol catechin has been reported to have antiallergic and anti-inflammatory activities, but its effect on monocytes has not yet been explored. To elucidate the mechanisms of the anti-inflammatory effect of catechin, we studied the effect of catechin, especially epigallocatechin gallate (EGCG), on the apoptosis of monocytes. Isolated peripheral blood monocytes were incubated without or with catechin, and apoptosis was evaluated by annexin V and propidium iodide double-staining or terminal deoxynucleotidyl assay. The activation of caspases 3, 8, and 9 was also evaluated by flow cytometry. The influence of GM-CSF or LPS, the known monocyte survival factors, on the EGCG-induced apoptosis of monocytes was investigated. Among the 4 catechin derivatives tested, EGCG and epicatechin gallate induced apoptosis of monocytes. Caspases 3, 8, and 9, which play a central role in the apoptotic cascade, were dose-dependently activated by EGCG treatment. The EGCG-induced apoptosis of monocytes was not affected by GM-CSF or LPS. Catechin, especially EGCG, by promoting monocytic apoptosis, may be a new promising anti-inflammatory agent, and should be tested in clinical trials.