• Genomics & Informatics
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• 제7권2호
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• pp.97-106
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• 2009

Epigallocatechin gallate (EGCG), a well-known antioxidant molecule, has been reported to cause hepatotoxicity when used in excess. However, the mechanism underlying EGCG-induced hepatotoxicity is still unclear. To better understand the mode of action of EGCG-induced hepatotoxicity, we examined the effect of EGCG on human hepatic gene expression in HepG2 cells using microarrays. Analyses of microarray data revealed more than 1300 differentially expressed genes with a variety of biological processes. Upregulated genes showed a primary involvement with protein-related biological processes, such as protein synthesis, protein modification, and protein trafficking, while downregulated genes demonstrated a strong association with lipid transport. Genes involved in cellular stress responses were highly upregulated by EGCG treatment, in particular genes involved in endoplasmic reticulum (ER) stress, such as GADD153, GADD34, and ATF3. In addition, changes in genes responsible for cholesterol synthesis and lipid transport were also observed, which explains the high accumulation of EGCG-induced lipids. We also identified other regulatory genes that might aid in clarifying the molecular mechanism underlying EGCG-induced hepatotoxicity.

• 약학회지
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• 제55권4호
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• pp.332-337
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• 2011

The purpose of this study was to investigate the effect of epigallocatechin gallate (EGCG) on the pharmacokinetics of nimodipine in rats. Pharmacokinetic parameters of nimodipine were determined in rats after oral and iv administration of nimodipine with or without EGCG and also the effect of EGCG on the cytochrome P450 (CYP) 3A4 and P-glycoprotein (P-gp) activity were evaluated. EGCG inhibited CYP3A4 and P-gp activity. EGCG significantly increased the area under the plasma concentration-time curve (AUC) and peak plasma concentration ($C_{max}$) of nimodipine. The absolute bioavailability (AB%) and relative bioavailability (RB%) of nimodipine by EGCG were increased by 16% and by 48%, respectively, compared to the control. In contrast, EGCG did not affect the intravenous pharmacokinetics of nimodipine. Based on these results, the increased bioavailability of nimodipine might be due to inhibition of CYP3A4 in the small intestine and/or in the liver and inhibition of P-gp in the small intestine by EGCG.

• Archives of Pharmacal Research
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• 제28권8호
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• pp.914-922
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• 2005

The present study was designed to examine the effects of green tea extract (CUMC6335) and epigallocatechin gallate (EGCG) on secretion of catecholamines (CA) in the isolated perfused rabbit adrenal gland. In the presence of CUMC6335 $(200 {\mu}g/mL)$ into an adrenal vein for 60min, CA secretory responses evoked by ACh (5.32 mM), high $K^+$ (56 mM), DMPP $(100{\mu}M \;for\;2min)$, and Bay-K-8644 $(10{\mu}M\;for\;4min)$ from the isolated perfused rabbit adrenal glands were greatly inhibited in a time-dependent fashion. However, EGCG $(10{\mu}g/mL)$ did not affect CA release evoked by ACh, high $K^+$, and Bay-K-8644. CUMC6335 itself failed to affect basal catecholamine output. Taken together, these results demonstrate that CUMC6335 inhibits CA secretion evoked by stimulation of cholinergic nicotinic receptors, as well as the direct membrane depolarization from the isolated perfused rabbit adrenal gland. It is thought that this inhibitory effect of CUMC6335 may be due at least in part to the blocking action of the L-type dihydropyridine calcium channels in the rabbit adrenomedullary chromaffin cells, which is relevant to the cholinergic nicotinic blockade. It seems that there is a big difference in mode of action between CUMC6335 and EGCG.

• 한국식품영양학회지
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• 제30권5호
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• pp.1035-1041
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• 2017

(-)-Epigallocatechin-3-gallate (EGCG) is a major catechin found in green tea. It is reported that EGCG possesses various health benefits including anti-cancer, antioxidant, anti-diabetes, and anti-obesity. The objective of this study was to investigate the effects of EGCG on adipogenesis via activation of AMP-activated protein kinase (AMPK) pathway in 3T3-L1 preadipocytes. In order to determine the effects of EGCG on adipogenesis, preadipocyte differentiation was induced in the presence or absence of EGCG ($0{\sim}100{\mu}M$) for a period of 6 days. EGCG significantly inhibited fat accumulation and suppressed the expression of adipogenic specific proteins including peroxisome proliferator-activated receptor (PPAR)-${\gamma}$. Also, EGCG markedly increased the activation of AMPK and acetyl-CoA carboxylase (ACC) and the production of intracellular reactive oxygen species (ROS). However, any pretreatment with a specific AMPK inhibitor, compound C, abolished the inhibitory effects of the EGCG on $PPAR{\gamma}$ expression. This study suggests that EGCG has anti-adipogenic effects through modulation of the AMPK signaling pathway and therefore, may be a promising antiobesity agent.

• 한국식품과학회지
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• 제48권4호
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• pp.329-334
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• 2016

천연 녹차추출물인 epigallocatechin gallate (EGCG)의 메추리알 장조림에서 천연식품첨가제로서의 적용 가능성을 탐색하고자 S. Enteritidis에 대한 항미생물 활성을 냉장온도($4^{\circ}C$)와 일반실내온도($25^{\circ}C$)에서 평가하였다. 순수배양액에서의 실험결과 첨가된 EGCG의 농도($200-800{\mu}g/mL$)에 따라 $4^{\circ}C$에서 5일에서 16일 사이에서 그리고 $25^{\circ}C$에서 1일부터 6일 사이에서 S. Enteritidis균이 검출한계 이하로 억제되는 것이 관찰되었다. 이와 대조적으로 간장소스에서의 실험에서는 $25^{\circ}C$에서 첨가된 EGCG의 농도와 관계없이 S. Enteritidis균이 억제되지 않았으며, $4^{\circ}C$에서는 $400{\mu}g/mL$ 이상의 농도일 때 16일에 S. Enteritidis균이 검출한계 이하로 억제되는 것이 관찰되었다. 메추리알 장조림의 경우, $25^{\circ}C$에서 간장소스의 결과와 동일하게 어떠한 EGCG의 항미생물 활성이 나타나지 않았지만, $4^{\circ}C$에서 $400{\mu}g/mL$의 EGCG 농도 첨가 시 16일에 S. Enteritidis 균이 검출한계 이하로 억제되는 것이 확인되었다. 따라서, 메추리알 장조림 완제품에서 EGCG는 $4^{\circ}C$ 이하의 저온유통체계(cold chain system)하에서 S. Enteritidis과 같은 식중독세균을 제어할 수 있는 적합한 천연 식품첨가제로서 활용될 수 있을 것으로 기대된다.

• 한국식품저장유통학회지
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• 제13권4호
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• pp.421-426
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• 2006

제주산 건조녹차를 $55^{\circ}C$에서 15분간 추출하여 여과한 다음 PET병에 밀봉하여 $4^{\circ}C$ 저온과 실내 및 실외에 각각 보관하면서 보존안정성을 측정하였다 저장기간에 따라 L값은 거의 변화가 없었지만 a값이 감소하고 b값이 증가하면서 전체적인 색깔이 짙어졌으며, 실내에서 저장한 경우가 실외저장이나 저온저장보다 저장기간이 길어질수록 더 짙어졌다. 녹차추출물 중의 주요 카테킨류로는(-)-epigallocatechin, (-)-epigallocatechin gallate, epicatechin, (+)-catechin, epicatechin gallate순이었으며, EGC의 함량비율이 전체의 53.8%이었다. 총 카테킨 함량은 저온저장에서는 큰 차이가 없었지만, 실내 및 실외 저장한 경우에는 $148.87{\mu}g/mL$에서 14주일 후에는 각각 133.98, $141.87{\mu}g/mL$로 10%, 4.7%가 감소하였다. 카페인 함량은 저장조건에 관계없이 전체적으로 증가하였으며, 총 폴리페놀 함량은 저장조건 및 저장기간에 따른 차이가 크지 않았다. 전자공여능은 저장방법과 저장기간에 관계없이 60% 이상의 효과가 있었다. 아질산염 소거능은 pH 1.2에서 90% 이상으로 가장 높았으며, pH가 증가할수록 감소하다가 pH 6.0에서는 아질산염 소거효과가 없어졌다. 3개월 이상 경과하더라도 색깔, 폴리페놀성분, 항산화작용등의 변화가 크지 않았다. $95^{\circ}C$에서 10분간 살균으로 보관기간 중에 미생물의 증식이 인정되지 않아 저장안전성을 유지하는 것으로 판단되었다.

• 한국영양학회:학술대회논문집
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• 한국영양학회 2002년도 춘계학술대회
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• pp.92-92
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• 2002

• Food Science and Biotechnology
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• 제17권5호
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• pp.1016-1020
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• 2008

Parameters of soluble solids, amino acids, catechins, and color difference of 24 green tea samples from China and Korea were determined. The levels of soluble solids, amino acids, total catechins, and infusion lightness in tea samples from Korea were higher than those from China. Concentrations of epigallocatechin galate and epigallocatechin in teas from China were higher than tea samples from Korea. Geographical origin of teas from the 2 countries was discriminated using parameters of infusion lightness, gallocatechin, and total catechins and applying principal component analysis.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.161.2-162
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• 2003

We have previously reported that green tea catechins(GTC) displayed anti-thrombotic activity, and that this might be due to anti-platelet rather than anti-coagulation effects. In the present study, we have compared the anti-platelet activity and mechanism of epigallocatechin gallate(EGCG) and epigaliocatechin(EGC), which are two major components of GTC. (omitted)

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2222-2226
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• 2011

Amylase is a digestive enzyme that catalyses the starch into sugar. It has been reported that the green tea flavonoid (or polyphenols) (-)-epigallocatechin 3-gallate (EGCG) inhibits human salivary ${\alpha}$-amylase (HSA) and induced anti-nutritional effects. In this study, we performed docking study for seven EGCG-like flavonoids and HSA to understand the interaction mechanism of HSA and EGCG and suggest new possible flavonoid inhibitors of HSA. As a result, EGCG and (-)-epicatechin gallate (ECG) bind to HSA with complex hydrogen bonding interactions. These hydrogen bonding interactions are important for inhibitory activity of EGCG against HSA. We suggested that ECG can be a potent inhibitor of HSA. This study will be helpful to understand the mechanism of inhibition of HSA by EGCG and give insights to develop therapeutic strategies against diabetes.