• 생약학회지
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• 제50권3호
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• pp.198-204
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• 2019

A facile and convenient method was developed for the mass production of epigallocatechin gallate (EGCG) rich green tea extract (Er-GTE). The Er-GTE was successfully obtained from the crude water extract of green tea by the combination of two step purification, i.e., a simple adsorption process on the cation exchange resins (Trilite SCR-B) followed by the chromatography with Diaion HP-20 resins. The green tea extract produced by water extraction under $45^{\circ}C$ was subjected to adsorb on the strongly acidic cation exchange resin, Trilite SCR-B. The eluate passed through the resin was reabsorbed on Diaion HP-20 resin, which was subjected to elute with a mixture of water and alcohol by conventional chromatographical manner. The EGCG content in Er-GTE was estimated above 97% by HP-LC analysis and the newly developed method was regarded as the most suitable and appropriate process for the mass production of epigallocatechin gallate rich green tea extract (Er-GTE).

• 한국식품과학회지
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• 제30권4호
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• pp.970-975
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• 1998

약용 식물로부터 여러 효소의 저해제를 탐색 하였다. 한국산 우롱차엽으로부터 80%의 아세톤 추출물을 Sephadex LH-20, MCI-gel, Fuji gel 등을 사용하여 분리하였고 이 화합물은 Anisaldehyde 및 $FeCl_3$에 붉은색과 청색을 나타내었다. 이 화합물의 유도체화에 의한 기기분석 결과에서 상부는 -(-)epicatechin로 하부는 -(-)epigallocatechin 3-O-gallate 결합된 dimeric proanthocyanidin 종류인, $epicatechin-(4{\beta}{\rightarrow}8)-epigallocatechin{\;}3-O-gallate$로 화학 구조가 결정되었다. Xanthin oxidase 저해 효과에서는 $50{\;}{\mu}mole$에서 62%의 저해를 보여주어 앞으로 통풍 예방 기능성 식품 신소재로서의 이용이 가능하다는 것을 확인하였다.

• Advances in Traditional Medicine
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• 제8권2호
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• pp.171-177
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• 2008

Epigallocatechin 3-gallate (EGCG), one of the major catechins of tea, was isolated from the decaffeinated, crude methanolic extract of Indian green tea (Camellia sinensis L. O. Kuntze) using chromatographic techniques. EGCG was then screened for antidiarrhoeal activity against 30 strains (clinical isolates) of V. cholerae, which is a well known Gram negative bacillus functioning as the pathogen of cholera. V. cholerae strains like V. cholerae 69, 71, 83, 214, 978, 1021, 1315, 1347, 1348, 569B and ATCC 14033 were inhibited by EGCG at a concentration of $25\;{\mu}g/ml$ whereas V. cholerae 10, 522, 976 were even more sensitive, being inhibited at $10\;{\mu}g/ml$ level. However, V. cholerae DN 16, DN 26, 30, 42, 56, 58, 113, 117, 564, 593, 972 and ATCC 14035 were inhibited at $50\;{\mu}g/ml$ level of EGCG. Only four strains were inhibited at $100\;{\mu}g/ml$. In this study the isolated compound was found to be bacteriostatic in its mechanism of action. In the in vivo experiment using the rabbit ileal loop model two different dosages of EGCG ($500\;{\mu}g/ml$ and $1,000\;{\mu}g/ml$) were able to protect the animals when they were challenged with V. cholerae 569B in the ileum.

• Nutritional Sciences
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• 제9권1호
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• pp.3-8
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• 2006

Functional damage to microvascular endothelial cells by hyperglycemia is thought to be one of the critical risk factor.; in the impaired wound healing seen with diabetes mellitus. It is also thought that oxidative stress plays a significant role in this endothelial cell dysfunction. The present study examined the differential effects of flavonoids on endothelial cell dysfunction under high glucose conditions. Human endothelial cells exposed to 30 mmol/L glucose for 7 d were pre-treated with various flavonoids and pulse-treated with 0.2 mmol/L $H_2O_2$ for 30 min. High glucose markedly decreased cell viability with elevated oxidant generation and nuclear condensation. $H_2O_2$ insult exacerbated endothelial cytotoxicity due to chronic exposure to high glucose. (-)Epigallocatechin gallate and quercetin improved glucose-induced cell damage with the disappearnnce of apoptotic bodies, whereas apigenin intensified the glucose cytotoxicity. In addition, cell viability data revealed that these flavonoids of (-)epigallocatechin gallate and quercetin substantially attenuated both high glucose- and $H_2O_2$- induced dual endothelial damage. These results suggest that (-)epigallocatechin gallate and quercetin may be beneficial agents for improving endothelial cell dysfunction induced by high glucose and may prevent or reduce the development of diabetic vascular complications.

• 생약학회지
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• 제30권4호
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• pp.397-403
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• 1999

Tyrosinase plays an important role in the process of melanin polymer biosynthesis. Therefore, the enzyme inhibitors have been of great concern as cosmetics to have skin-whitening effects on the local hyperpigmentation. During the search for new inhibitory compounds on melanin polymer biosynthesis from natural sources, MeOH extracts of 589 higher plants were tested for the inhibitory effect on tyrosinase activity by the muschroom tyrosinase assay in vitro. Among plants tested, the leaves of Cercis chinensis exhibited potent inhibitory effect on mushroom tyrosinase activity. Subsequently seven active compounds were isolated from the ethyl acetate soluble part of acetone extract of the leaves of C. chinensis by the activity guided fractionation monitoring the inhibitory effect on tyrosinase activity. Their chemical structures were identified as $kaempferol-3-0-{\alpha}-L-rhamnoside$, quercitrin, $myricetin-3-0-{\alpha}-L-rhamnoside$, myricetin-3-0-(2'-O-galloyl)- ${\alpha}$ -L-rhamopyranoside (desmanthin), (-)-epicatechin-3-0-gallate, (-)-epigallocatechin-3-0-gallate, and methyl gallate on the basis of the speculation of spectral data and chemical reaction. Among the flavonol rhamnosides, myricetin-3-0-(2'-O-galloyl)- -L-rhamnoside(desmanthin) showed most potent inhibitory effect on tyrosinase activity and the structure of B-ring in flavonol moiety was related to the activity. (-)-Epigallocatechin-3-O-gallate having pyrogallol group in flavan-3-ol moiety exhibited more potent inhibitory effect than (-)-epicatechin-3-0-gallate having catechol group in flavan-3-ol moiety on mushroom tyrosinase activity.

• 한국식품과학회지
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• 제43권4호
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• pp.483-489
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• 2011

본 연구에서는 다양한 생리활성이 보고된 폴리페놀 화합물인 EGCG의 화학안정성, H2O2 생성능 및 세포독성에 대하여 다양한 항산화제와의 조합에 의한 변화를 분석하였다. EGCG는 생리적 조건에서 갈색화합물로 산화되면서 불안정화되는데, catalase를 제외한 각종 항산화제제 SOD, ascorbic acid, NAC 및 GSH는 EGCG 갈색산화물의 생성을 유의적으로 저해하였다. EGCG에 의해 생성되는 $H_2O_2$는 catalase에 의해 거의 완벽하게 제거되었으며, SOD와 NAC에 의해서도 유의적으로 감소하였다. 하지만 GSH 및 고농도의 ascorbic acid의 존재 시 오히려 $H_2O_2$ 수준이 증가하는 현상을 나타내었다. EGCG의 HeLa 및 HT-29 세포에 대한 독성은 catalase, SOD 및 NAC 등과 같은 항산화제 존재 하에 유의적으로 감소하였고 NAC에 의한 EGCG 세포독성의 감소는 첨가된 NAC의 농도 증가에 따라 더욱 두드러졌다. 그러나 GSH 존재하에 EGCG의 독성은 GSH와 EGCG농도에 따라 다른 조절 양상을 나타내었으며, ascorbic acid에 의해서 EGCG의 세포독성이 약간 증가하는 현상을 나타내었다. 본 결과는 EGCG와 함께 처리된 다양한 항산화제들이 ROS의 소거 뿐만 아니라 EGCG 화학안정성 등 다른 요인에 영향을 미칠 수 있으며, 항산화제의 존재 하에 변형된 EGCG활성에 대해 ROS관련 기작 외에 다양한 요인들에 대한 고려가 함께 이루어져야 함을 시사한다.

• 한국식생활문화학회지
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• 제18권5호
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• pp.443-456
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• 2003

The lyophilization of the solution extracted from 60 percent of acetone applied to persimmon leaves, the compounding process in accordance with the solution's concentration, and the gel filteration through Sephadex G-50 of biologically activated substances obstructing enzyme activity, such as tyrosinase, xanthine oxidase, and angiotesin converting enzyme (ACE) led to the assumption that polyphenol was the compound serving as biologically activated substances obstructing enzyme activity. Xanthine oxidase involved in pruine metabolism oxidizes hypoxanthine to xanthine and xanthine to uric acid. In the continuous study for natural compound, nine flavan-3-ols have been isolated from the persimmon leaves. The structures of (+)-catechin, (+)-gallocatechin, procyanidin B-1, pyrocyanidin C-1, prodelphinidin B-3, gallocatechin-$(4{\alpha}{\rightarrow}8)$-catechin, procyanidin B-7-3-O-gallate, procyanidin C-1-3'-3'-3'-O-trigallate and (-)-epigallocatechin-$(4{\alpha}{\rightarrow}8)$-epigallocatechin-$(4{\alpha}{\rightarrow}8)$-catechin were established by NMR and their inhibitory effect on xanthine oxidase activity was investigated. Procyanidin B-7-3-O-gallate, (-)-epigallocatechin-$(4{\alpha}{\rightarrow}8)$-epigallocatechin-$(4{\alpha}{\rightarrow}8)$-catechin and procyanidin C-1-3'-3'-3'-O-trigallate showed 94%, 90.69%, 80.90% inhibition at $100\;({\mu})M$ and inhibited on the angiotensin converting enzyme respectively. Procyanidin B-7-3-O-gallate and procyanidin C-1-3'-3'-3'-O-trigallate showed 66%, 63% inhibition at $100\;({\mu})M$ and inhibited on the xanthine oxidase competitively. Procyanidin C-1-3'-3'-3'-O-trigallate showed 70% inhibition at $100\;({\mu})M$ and inhibited on the tyrosinase competitively.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2002년도 창립10주년기념 및 국립독성연구원 의약품동등성평가부서 신설기념 국재학술대회:생물학적 동등성과 의약품 개발 전략을 위한 국제심포지움
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• pp.198-198
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• 2002

• 대한의용생체공학회:의공학회지
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• 제34권3호
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• pp.111-116
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• 2013

Finite element analysis(FEA) has been extensively applied in the analyses of biomechanical properties of stents. Geometrically, a closed-cell stent is an assembly of a number of repeated unit cells and exhibits periodicity in both longitudinal and circumferential directions. This study concentrates on various parameters of the FEA models for the analysis of drug-eluting biodegradable polymeric stents for application to the treatment of coronary artery disease. In order to determine the mechanical characteristics of biodegradable polymeric stents, FEA was used to model two different types of stents: tubular stents(TS) and helicoidal stents(HS). For this modeling, epigallocatechin-3-O-gallate (EGCG)-eluting poly[(L-lactide-co-${\varepsilon}$-caprolactone), PLCL] (E-PLCL) was chosen as drug-eluting stent materials. E-PLCL was prepared by blending PLCL with 5% EGCG as previously described. In addition, the effects of EGCG blending on the mechanical properties of PLCL were investigated for both types of stent models. EGCG did not affect tensile strength at break, but significantly increased elastic modulus of PLCL. It is suggested that FEA is a cost-effective method to improve the design of drug-eluting biodegradable polymeric stents.

• 한국식품과학회지
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• 제35권5호
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• pp.959-967
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• 2003

한국산 배를 60% acetone으로 추출하여 Sephadex LH-20 gel column chromatography, MCI-CHP 20 gel column chromatography, Bondapack $C_{18}$ gel column chromatography을 이용하여 TLC와 HPLC로 순도를 검증한 후 4종의 polyphenol 화합물을 분리, 정제하였다. Compound A와 B는 Sepadex LH-20 gel column chromatography에서 증류수상에서 용출되었고 compound C는 40% methanol상에서 용출됨을 보아 compound B와 compound C는 흡착성이 강한 polyphenol 화합물이라 추정되었다. 분리, 정제한 4종의 compound를 NMR, FAM-mass 및 FT-IR를 이용하여 화학구조를 결정한 결과 compound A는 (+)-catechin, compound B는 (+)-gallocatechin, compound C는 (-)-epigallocatechin이고 compound D는 procyanidin B-3-3-o-gallate로 밝혀졌다.