• Journal of Life Science
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• v.13 no.6
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• pp.924-932
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• 2003

Epigallocatechin-3 Gallate (EGCG), a major constituent of green tea, has attracted increasing interest because of its many reported health benefits. Here we demonstrate for the first time that EGCG stimulates phospholipase D (PLD) activity in U87 human astroglioma cells. EGCG-induced PLD activation was abolished by the phospholipase C (PLC) inhibitor and a lipase inactive PLC-\gama1$ mutant, and was dependent on intracellular $Ca^{ 2+}$, and possibly involved $Ca^{ 2+}$ calmodulin-dependent protein kinase II (CaM kinase II). Interestingly, EGCG induced translocation of PLC-\gama1$ from the cytosol to the membrane and PLC-\gama1$interaction with PLD1. Taken together, these results demonstrate for the first time that in human astroglioma cells, EGCG regulates PLD activity via a signaling pathway involving a PLC-\gama1$ (inositol 1,4,5-trisphosphate-$Ca^{ 2+}$)-CaM kinase II-PLD pathway.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.5
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• pp.259-266
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• 2011

The aim of this study was to evaluate the preventive role of epigallocatechin-3 gallate (EGCG, a derivative of green tea) in ischemia/reperfusion (I/R) injury of isolated rat hearts. It has been suggested that EGCG has beneficial health effects, including prevention of cancer and heart disease, and it is also a potent antioxidant. Rat hearts were subjected to 20 min of normoxia, 20 min of zero-flow ischemia and then 50 min of reperfusion. EGCG was perfused 10 min before ischemia and during the whole reperfusion period. EGCG significantly increased left ventricular developed pressure (LVDP) and increased maximum positive and negative dP/dt (+/-dP/dtmax). EGCG also significantly increased the coronary flow (CF) at baseline before ischemia and at the onset of the reperfusion period. Moreover, EGCG decreased left ventricular end diastolic pressure (LVEDP). This study showed that lipid peroxydation was inhibited and Mn-SOD and catalase expressions were increased in the presence of EGCG. In addition, EGCG increased levels of Bcl-2, Mn-superoxide dismutase (SOD), and catalase expression and decreased levels of Bax and increased the ratio of Bcl-2/Bax in isolated rat hearts. Cleaved caspase-3 was decreased after EGCG treatment. EGCG markedly decreased the infarct size while attenuating the increase in lactate dehydrogenase (LDH) levels in the effluent. In summary, we suggest that EGCG has a protective effect on I/R-associated hemodynamic alteration and injury by acting as an antioxidant and anti-apoptotic agent in one.

• Korean Journal of Pharmacognosy
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• v.49 no.4
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• pp.328-335
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• 2018

'EGCG(epigallocatechin gallate) rich Green Tea extract(EGTE)' was prepared by a convenient chromatographical manner using water and alcohol which was regarded as the most suitable and appropriate process for food manufacturing. The EGCG content in EGTE was estimated above 97%. Analysis of polyphenol components in green tea, i.e., catechin(C), epigallocatechin(EGC), epicatechin(EC), epigallocatechin gallate(EGCG), epicatechin gallate(ECG) and caffeine was performed by HPLC. The optimized HPLC method exhibited a good linearity of calibration curve, accuracy and precision. The long-term stability evaluation of EGTE was carried out with a powdered formulation and solution formulation by estimating the color change and measuring the EGCG content by HPLC analysis for one year. The EGCG content of the powdered EGTE stored in a transparent bottle at room temperature was retained over 97% at the end of the experimental period. The EGCG content of 0.1% water solution of EGTE stored in a transparent bottle at RT were observed to decrease below 30%, whereas that stored at $2^{\circ}C$ retained over 70%, respectively. These results suggested that a powdered formulation could be recommended for the commercialized nutraceutical product of EGTE rather than a solution formulation.

• Journal of Dairy Science and Biotechnology
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• v.34 no.2
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• pp.69-74
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• 2016

The main constituent of tea catechins, EGCG [(-)-Epigallocatechin-3-gallate], could inhibit the growth of various microorganisms and differently affect gram-positive and gram-negative bacteria. Antimicrobial activity of EGCG, a compound from green tea (Camellia sinensis) extract, against Cronobacter spp. and Salmonella spp. was studied to evaluate the possibility of using EGCG as a natural food additive in various dairy products. In pure TSB culture, the growth of Cronobacter spp. was suppressed below the detection limit (1 log CFU/mL) depending on EGCG concentration ($600{\sim}800{\mu}g/mL$), after 5~16 days at $4^{\circ}C$. Similarly, the growth of Salmonella spp. was suppressed below the detection limit (1 log CFU/mL) depending on EGCG concentration ($400{\sim}800{\mu}g/mL$), after 5~16 days at $4^{\circ}C$. Therefore, these results suggest that EGCG could be used as an effective additive to inhibit the growth of Cronobacter spp. and Salmonella spp. in various dairy products, such as yoghurt, cheese, dried infant powder, and so on.

• Journal of Chest Surgery
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• v.40 no.4 s.273
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• pp.256-263
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• 2007

Background: Intimal hyperpiasia is characterized by a proliferation of vascular smooth muscle cells in the intimal layer Epigallocatechin-3-gallate (EGCG) is known to suppress smooth muscle cell proliferation. We propose that EGCG may have a protective effect against the development of intimal hyperplasia through the suppression of smooth muscle cell proliferation. Material and Method: Human umbilical vein endothelial cells (HUVEC) and rat aortic smooth muscle cells (RASMC) were cultured with different concentrations of EGCG, and proliferation and migration speed were measured. In 20 dogs, the autologous jugular veins were interposed into the carotid arteries. For the study group (n=10), the graft was stored for 30 minutes in EGCG solution and 300mM EGCG was applied to the perivascular space after grafting. After 6 weeks, the intimal and medial thickness was measured. Result: The proliferation of RASMC and HUVEC was suppressed with EGCG. The migration of RASMC was suppressed with EGCG, but that of HUVEC was not affected. In the in vivo study, the intimal thickness was thinner in EGCG group than in the control group (p<0.05), but the medial thickness did not show any difference. The intimal/medial thickness ratio was lower in the EGCG group (p<0.05). Conclusion: EGCG suppresses intimal hyperplasia after vascular grafting, and this may be mediated by prevention of migration and proliferation of vascular smooth muscle cells. The use of EGCG may offer new therapeutic modality to prevent intimal hyperplasia.

• Korean Journal of Food Science and Technology
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• v.43 no.4
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• pp.483-489
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• 2011

Epigallocatechin-3-gallate (EGCG) is a polyphenolic compound frequently found in green tea, and its physiological actions have been extensively investigated. In the present study, changes in chemical stability and cytotoxic properties of EGCG in the presence of different types of antioxidants were investigated. The antioxidants used modulated the chemical stability of EGCG. Superoxide dismutase (SOD) significantly increased EGCG stability; EGCG was less stable in the presence of catalase. Ascorbic acid, N-acetylcysteine (NAC), and glutathione (GSH) stabilized EGCG concentration dependently. The $H_2O_2$ level generated from EGCG was decreased by catalase, SOD, and NAC but not by GSH. The cytotoxic effects of EGCG also decreased in the presence of NAC, catalase, and SOD. GSH, however, showed a complicated modulatory pattern according to the EGCG and GSH concentrations, and ascorbic acid rather enhanced EGCG toxicity. The results suggest that certain antioxidants could modulate the cytotoxic properties of EGCG in a cell culture system not only by removing reactive oxygen species but by modulating chemical stability and other factors, which should be considered carefully when studying reactive oxygen species-dependent mechanisms of EGCG.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1293-1299
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• 2017

Obesity contributes to the development of diseases, such as type II diabetes, hypertension, coronary heart disease, and cancer. In addition, oxidative stress caused by reactive oxygen species (ROS) is recognized widely as a contributing factor in the development of chronic diseases. This study was examined the antioxidant and anti-adipogenic activities of epigallocatechin-3-gallate (EGCG) in 3T3-L1 preadipocytes. 3T3-L1 cells were differentiated with or without EGCG for 6 days. The production of glutathione (GSH) and the activities of the antioxidant enzymes, such as glutathione reductase (GR), glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD) were measured. EGCG inhibited significantly the lipid accumulation and the expression of adipogenic specific proteins including CCAAT/enhancer binding protein ${\alpha}$ and adipocyte fatty acid binding protein. The production of intracellular ROS was decreased significantly by EGCG in 3T3-L1 cells. EGCG increased the GSH production and the activities of GPx, GR, CAT, and SOD. Moreover, EGCG increased the protein expression of glutamate-cysteine ligase and heme oxygenase-1 in 3T3-L1 cells. These results suggest that EGCG increased the activity and expression of antioxidant enzymes and suppressed the lipid accumulation in 3T3-L1 cells. Therefore, the use of phytochemicals that can maintain the GSH redox balance in adipose tissue could be promising for reducing obesity.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.531-541
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• 2018

Purpose : To evaluate the acute cytotoxic effect of polyhexamethylene biguanide (PHMB), epigallocatechin gallate (EGCG) and PHMB/EGCG mixture on the cultured human corneal epithelial cell (HCEpiC). Methods : HCEpiCs were cultured in the media of HCEpiC containing 0.00001~0.005% PHMB, 0.001~5% EGCG and 0.00005% PHMB/0.05% EGCG mixture respectively for 30, 60, 120 and 240 min. Cultured HCEpiCs were fixed and stained with Draq5 and cell viability and apoptosis were evaluated using confocal microscope and ImageXpress $Ultra^{TM}$. Results : Cultured HCEpiC did not show cytotoxic effect at below 0.00005% PHMB and below 0.05% EGCG concentration. In the media containing 0.00005% PHMB/0.05% EGCG, acute cytototoxic effect was not found, whereas damaged HCEpiCS were increased and survival cells were decreased in the media incubated for 240 min. Conclusion : The mixture of 0.00005% PHMB/0.05% EGCG showed non acute cytotoxic effect on the cultured HCEpiCs, however it is needed to investigate its chronic cytotoxic effect.

• Food Science and Preservation
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• v.16 no.6
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• pp.924-928
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• 2009

Green tea has been shown to have multifunctional health-promoting properties including cholesterol level control an antidiabetic effect and anticancer, antioxidant, and antimicrobial properties, inboth in vivo and in vitro experiments.We earlier reported antifungal and antibacterial effects of green tea extract by investigating cell membrane functions. The purpose of the present study was to purify and identify antimicrobial substances from green tea extract. Such materials were extracted from green tea (Camellia sinensis. var. sinensis) and purified by high-performance liquid chromatography. The antimicrobial substances in the extract were identified as epicatechin gallate and epigallocatechin gallate by nuclear magnetic resonance spectrophotometry.

• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.720-724
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• 2011

Differences in sensory evaluation, physicochemical properties and antioxidant activities between green tea concentrations and tannase-treated green tea concentrations were measured in this study. The results showed that pH did not differ dependent on tannase treatment but antioxidant ability were slightly increased through tannase treatment without significant($p$ <0.05). However, the turbidity of the tannase-treated green tea concentration had significant difference to the non-treated concentration. The astringency, tested via sensory evaluation, decreased significantly after tannase treatment($p$ <0.05). Traces of epicatechin gallate(ECG) and epigallocatechin gallate(EGCG) also disappeared after the tannase treatment, due to the fact that the ester linkages in the catechin structure were broken by the tannase. It was concluded that tannase treatment of tea products is a very effective process for decreasing astringency and turbidity.