• The Korean Journal of Food And Nutrition
• /
• v.30 no.5
• /
• pp.1035-1041
• /
• 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.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.7
• /
• pp.2222-2226
• /
• 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.

• Korean Journal of Food Science and Technology
• /
• v.48 no.4
• /
• pp.329-334
• /
• 2016

The inhibitory effect of epigallocatechin gallate (EGCG), one of the antioxidants in green tea (Camellia sinensis), against Salmonella Enteritidis was evaluated in commercial braised quail eggs at two temperatures (4 and $25^{\circ}C$). Although S. Enteritidis was dose-dependently suppressed by EGCG in pure culture at $25^{\circ}C$, it was not inhibited in the sauce or eggs at this temperature. At low temperature ($4^{\circ}C$), S. Enteritidis was inhibited in both the sauce and eggs by $400{\mu}g/mL$ EGCG. Thus, EGCG at an appropriate concentration could be a useful food additive for inhibiting S. Enteritidis in braised quail eggs at low temperatures.

• Analytical Science and Technology
• /
• v.5 no.3
• /
• pp.333-338
• /
• 1992

The tea tannins, epigallocatechin, epigallocatechin gallate, were successfully separated by a Sephadex LH-20 column by the acetone based gradient elution. Each fractions was collected by monitoring at 280nm. Purified fractions were directly characterized by fast atom bombardment mass spectrometry. Epigallocatechin and epigallocatechin gallate were identified and shown as low as 70% purity in the reversed phase column. This revised method is more advantageous than known methods in purity and rapidity.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
• /
• 2002.04a
• /
• pp.29-40
• /
• 2002

감잎으로부터 통풍치료, 미백효과, 고혈압 억제효과의 개발목적으로 9종의 flavan-3-ol 화합물을 분리하였고 기기분석에 의해 화학구조를 자혔다. 각 화합물은 (+)-catechin (+)-gallocatechin procyanidinB-l, pyrocyanidin C-1, prodelphinidin B-3, gallocatechin-(4$\alpha$$\longrightarrow$8)-catechin과 감나무 잎에서 새로운물질인pocyanidin B-7-3-0-gallate, procyanidin C-1-3'-3" -3.'S _0-trigallate, (-)-epigallocatechin-(4 $\beta$ -18)-epigallocatechin-(4$\beta$-'8)-catechin 3종류를 발견하였다. 감잎으로부터 순수 분리한 polyphenol류의ACE 저해활성측정을 실험한 결과 pocyanidin B-7-3-0-gallate는 100rM농도에서 94%의 저해효과를 나타내었으며 epigallocatechin-(4$\beta$$\longrightarrow$8)-epigallo-catechin-(4$\beta$$\longrightarrow$8)-catechia procyanidin C-1-3'-3" -3f'.-0-trigallate는 각각 90.69, 80.90% 저해를 하였다. Xanthine oxidase 저해활성측정을 조사한 결과pocyanidin B-7-3-0-galtate와 pocyanidin C-1-3'-3" -3/'S _0-trigallate 즉, gallate가 붙은 호합물에서100rM의 농도에서 66%와 63%의 강한 저해효과를 나타났다. Tyrosinase 저해활성을 측정한 결과는pocyanidin C-1-3'-3" -3.'S _0-trigallate는 100rM에서 70%의 강한 저해효과를 나타냈으며,epigallocatechin-(4$\beta$$\longrightarrow$8)-epigallo-catechin-(4$\beta$$\longrightarrow$8)-catechin는 51%의 저해효과를 나타내었다. 산업적응용을 위해 분획한 폴리페놀군은 미백효과 검증실험인 tyrosinase 저해율 측정평가에서 폴리페놀 함량이 가장 높은 Fraction 111의 경우 Sooppm에서 74.2%의 높은 저해율을 나타내었다. 항산화력 실험에서는500pw1이상에서 강한 활성능을 보인 SOD 유사활성능을 제외한 나머지 DPPH와 xanthine oxidase 저해효과에서는 Fraction II와III 모두가50ppm이상에서 80% 이상의 높은 유리라디칼 소거능력을 나타내었다. 그리고 각 Fraction별 항균력 측정 결과 Fraction 르와 111이 우수하게 나타났고 항균활성은 그람음성균보다 그람양성균에서 효과적이었으며, 농도별 항균력시험 결과 농도가 증가할수록 비례하여 저해율도 증가함을 알 수 있었다. 첨가농도를 달리하여 미생물의 생육도를 측정한 결과, fraction II磎꼭\ulcorner경우 그람양성균에 대해 500 ppm 이상에서 뚜렷한 증식억제효과를 나타내었다.서 뚜렷한 증식억제효과를 나타내었다.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.8
• /
• pp.983-988
• /
• 2007

Epigallocatechin gallate (EGCG), a principal antioxidant derived from green tea, is one of the most extensively investigated chemopreventive phytochemicals. However, the effect of EGCG on proliferation in MDA-MB-231 breast cancer cell is not well known. We investigated the effect of EGCG on protein and mRNA expression related to cell proliferation in MDA-MB-231 human breast cancer cell lines. We cultured MDA-MB-231 cells in the presence of 0, 5, 10 and 20 ${\mu}m$ of EGCG. EGCG significantly inhibited the cancer cell proliferation (p<0.05). In MDA-MB-231 huamn breast cancer cell, EGCG lowered $ErbB_2$ and $ErbB_3$ protein as well as mRNA expression. In addition, protein and mRNA expression of phosphorylated Akt and total Akt were significantly decreased (p<0.05). We suggest that EGCG inhibits cell proliferation through $ErbB_2$, $ErbB_3$ and Akt cell signaling.

• Proceedings of the Korean Nutrition Society Conference
• /
• 2002.05a
• /
• pp.92-92
• /
• 2002

• Journal of Life Science
• /
• v.18 no.2
• /
• pp.273-278
• /
• 2008

Various biological resources from plants, animals, mushrooms, microorganisms, and foods were tested for the inhibitory activity against squalene synthase (SQS). Among 32 samples, more than one fourths (9 samples) exhibited significant SQS inhibitory activity. Interestingly, SQS inhibitory activity was detected in the samples such as green tea, fermented soybean paste, and plum juice. The SQS inhibitory activity of green tea was not only high but also stable. Its SQS inhibitors were supposed to be catechin derivatives, which have been known to be main bioactive components in green tea. The galloyl catechins showed higher SQS inhibitory activity compared to the nongalloyl catechins. Especially, (-)-epigallocatechin gallate appeared to be strongest inhibitor against squalene synthase ($IC_{50}=90{\mu}M$).

• Food Science and Preservation
• /
• v.13 no.4
• /
• pp.421-426
• /
• 2006

Preservation stability of the extract from dried green tea produced in Jeju, extracted at $55^{\circ}C$ for 15 min and bottled in PET container after filtration and then settled at $4^{\circ}C$, indoor at room temperature and outdoor, respectively, was estimated. Color L-value was almost constant but color of the extract became darkened during storage, especially in indoor storage. Main catechins of green tea extract were (-)-epigallocatechin, (-)-epigallocatechin gallate, epicatechin, (+)-catechin, epicatechin gallate in order, and the content of epigallocatechin was 53.8%. Nevertheless total catechin content was not changed in cold storage, and $4.7\sim10%$ of total catechins were reduced in outdoor or indoor storage after 14 weeks. Caffeine content were increased but total polyphenols were not changed largely during storage. Election donating abilities (EDA) showed more than 60% without influence of storage conditions and periods. Nitrite scavenging abilities (NSA) showed more than 90% at pH 1.2, but those were decreased gradually as pH increased, and then disappeared at pH 6.0. Color, polyphenols, antioxidant activities of extract were not so changed for more than 3 months. Microbial growth was not shown during same periods, due to heat treatment of the extracts at $95^{\circ}C$ for 10 min.

• Proceedings of the PSK Conference
• /
• 2003.04a
• /
• pp.161.2-162
• /
• 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)