• 한국식품영양과학회지
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• 제24권1호
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• pp.154-159
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• 1995

Inhibition of xanthine oxidase by tea extracts obtained from non-fermented tea(steamed green tea and roasted green tea), semi-fermented tea(oolong tea) and fermented tea(black tea) were investigated. The crude catechin fraciton had a hgher inhibitory effect against xanthine oxidase, and the effect was increased with the addition of tea extracts. Their inhibitory effect were hardly influenced until extracted three times with hot water. According to the investigation of catechins in the crude catechin fraction obtained from tea extracts, (-)-epicatechin-(EC), (-)-epicatechin gallate(ECg). (-)-epigallocatechin(EGC) and (-)-epigallocatechin gallate(EGCg) were 80.1$\mu\textrm{g}$/mg 113.5$\mu\textrm{g}$ /mg, 186.3$\mu\textrm{g}$/mg and 367.7$\mu\textrm{g}$/mg in steamed green tea, and 75.6$\mu\textrm{g}$/mg, 114.7$\mu\textrm{g}$/mg, 193.7 $\mu\textrm{g}$/mg and 381.9$\mu\textrm{g}$/mg in roasted green tea, and 69.4$\mu\textrm{g}$/mg, 110.0$\mu\textrm{g}$/mg, 127.1$\mu\textrm{g}$.mg and 464.9$\mu\textrm{g}$/mg in oolong tea, and 78.1$\mu\textrm{g}$/mg, 171.8$\mu\textrm{g}$/mg, 80.7$\mu\textrm{g}$/mg and 51.4$\mu\textrm{g}$/mg in black tea, respectively. Order of the content of these catechins was (-)-EGCg>(-)-EGC>(-)-ECg>(-)-EC in steamed green tea, roasted green tea and oolong tea, and was (-)-ECg>(-)-EGC>(-)-EC>(-)-EGCg in black tea. Also the concentration of catechins was hardly influeced until extracted three times. The inhibition ratio of xanthine oxidase by autherntic catechins was hardly influenced until extracted three times. The inhibition ratio of xanthine oxidase by authentic catechins was 94.9% and 87.6% by addition of 5.0$\mu\textrm{g}$/ml of (-)-EGCg and (-)-ECg, respectively. the inhibitors of xanthine oxidase were supposed to be due to (-)-ECg and (-)-EGCg in tea polyphenol compounds.

• 대한치주과학회:학술대회논문집
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• 대한치주과학회 2004년도 제44회 종합학술대회 연제초록
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• pp.153-154
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• 2004

• 생명과학회지
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• 제23권11호
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• pp.1404-1408
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• 2013

본 연구에서는 마우스 췌장의 선포세포(primary acinar cell)에서 에탄올에 의해 유도된 염증성 손상에 미치는 녹차의 생리활성 물질인 EGCG의 효과를 췌장분비 효소의 활성과 선포세포에서의 기능 회복 관련 마크로 알려진 유전자들(AMPK, RKIP 및 Reg1)의 발현 조절 측면에서 조사하였다. 대조군에 비해 에탄올이 처리된 세포에서는 ${\alpha}$-amylase와 chymotrypsin의 활성이 증가되었지만, EGCG 처리에 의하여 그들 활성이 유의적으로 감소하였다. 세포 생존 및 보호와 관련 있는 AMPK 인산화 수준은 에탄올 단독 처리시 그 발현이 감소하였지만, EGCG 처리에 의하여 유의적으로 회복되었다. 세포 사멸과 세포독성 조절과 연관이 있는 RKIP 또한 그 발현 경향이 AMPK인산화 변화의 정도와 유사하였다. 또한 베타세포 재생에 관여하는 Reg1 발현은 에탄올이 처리된 선포세포에 EGCG를 처리하였을 경우 그 발현량이 유의적으로 증가하였다. 이상의 결과들을 종합하여, 항산화성 폴리페놀인 EGCG는 알코올성 췌장염으로 인한 세포의 손상이나 당뇨병 예방과 회복에 치료적 효과를 가질 수 있다고 제안한다.

• 공업화학
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• 제18권2호
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• pp.130-135
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• 2007

EGCG의 안정성을 향상시키기 위해 ethosome에 포집을 시도하였다. 물에 에탄올을 첨가해서 EGCG의 용해도를 높임으로써 ethosome에 적정량의 EGCG이 포집될 수 있도록 하였다. EGCG 수용액의 농도와 ethosome 막을 구성하는 지질의 조성은 ethosome 입자크기와 포집효율에 상당한 영향을 미치는 것을 확인하고 ethosome의 액정상 형성은 편광 현미경을 사용하여 관측하였다. EGCG가 수용액 상태로 있을 때와 ethosome에 포집되어 있을 때, UV 또는 고온의 상태에서의 안정성을 비교한 결과 ethosome에 포집된 EGCG의 안정화 효과를 확인하였다. Ethosome에 토코페롤의 첨가는 UV에 의한 EGCG의 분해를 지연시켰다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.502-506
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• 2005

Three EGCG analogues were synthesized by the acceptor reaction of a glucansucrase from Leuconostoc mesenteroides B-1299CB with EGCG and sucrose. The transfer products was purified using Sephadex LG-20 column chromatography and high performance liquid chromatography (HPLC). EGCG-G1 and EGCG-G2 were novel compounds for the first time reported in this paper. EGCG glycosides showed similar or slower antioxidative effects according to their structures $(EGCG{\geq}EGCG-G1>EGCG-G1'>EGCG-G2)$. However, the water solubilities of the EGCG-G1, EGCG-G1' and EGCG-G2 were 52, 76 and 140 times higher than that of EGCG. Furthermore, they showed more browning resistance against UV irradiation than EGCG.

• Bulletin of the Korean Chemical Society
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• 제29권9호
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• pp.1717-1722
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• 2008

The 70 kDa heat-shock protein (Hsp70) involved in various cellular functions, such as protein folding, translocation and degradation, regulates apoptosis in cancer cells. Recently, it has been reported that the green tea flavonoid (−)-epigallocatechin 3-gallate (EGCG) induces apoptosis in numerous cancer cell lines and could inhibit the anti-apoptotic effect of human Hsp70 ATPase domain (hATPase). In the present study, docking model between EGCG and hATPase was determined using automated docking study. Epi-gallo moiety in EGCG participated in hydrogen bonds with side chain of K71 and T204, and has metal chelating interaction with hATPase. Hydroxyl group of catechin moiety also participated in metal chelating hydrogen bond. Gallate moiety had two hydrogen bondings with side chains of E268 and K271, and hydrophobic interaction with Y15. Based on this docking model, we determined two pharmacophore maps consisted of six or seven features, including three or four hydrogen bonding acceptors, two hydrogen bonding donors, and one lipophilic. We searched a flavonoid database including 23 naturally occurring flavonoids and 10 polyphenolic flavonoids with two maps, and myricetin and GC were hit by map I. Three hydroxyl groups of B-ring in myricetin and gallo moiety of GC formed important hydrogen bonds with hATPase. 7-OH of A-ring in myricetin and OH group of catechin moiety in GC are hydrogen bond donors similar to gallate moiety in EGCG. From these results, it can be proposed that myricetin and GC can be potent inhibitors of hATPase. This study will be helpful to understand the mechanism of inhibition of hATPase by EGCG and give insights to develop potent inhibitors of hATPase.

• Restorative Dentistry and Endodontics
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• 제48권2호
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• pp.13.1-13.11
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• 2023

Objectives: Natural extracts have been investigated as a biomimetic strategy to mechanically strengthen the collagen network and control the biodegradation of extracellular matrix. This study evaluated the effect of epigallocatechin-3-gallate (EGCG) on abfraction lesions prior to the composite resin. Materials and Methods: The sample consisted of 30 patients (aged between 28 and 60 years) with abfraction lesions located in 2 homologous premolars. The teeth were randomly assigned according to dentin treatment: 0.02% EGCG solution or distilled water (control). After enamel acid etching, the solutions were applied immediately for 1 minute. The teeth were restored with Universal Adhesive (3M) and Filtek Z350 XT (3M). Analyzes were done by 2 independent examiners using modified USPHS (retention, secondary caries, marginal adaptation, and postoperative sensitivity) and photographic (color, marginal pigmentation, and anatomical form) criteria at baseline (7 days) and final (18 months). The data analysis used Friedman and Wilcoxon signed-rank tests (α = 0.05). Results: At baseline, all restorations were evaluated as alpha for all criteria. After 18 months, restorations were evaluated as alpha for secondary caries, color, and marginal pigmentation. There was significant difference between baseline and 18 months (p = 0.009) for marginal adaptation and postoperative sensitivity (p = 0.029), but no significant difference were verified between treatments (p = 0.433). The EGCG group had a restoration retention rate of 93.3%, while the control group had 96.7%. Conclusions: The application of EGCG solution on abfraction lesions did not significantly influence the survival of the restorations based on clinical and photographic criteria.

• 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)

• The Korean Journal of Physiology and Pharmacology
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• 제9권4호
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• pp.239-246
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• 2005

In the central nervous system, nitric oxide (NO) is associated with many pathological diseases such as brain ischemia, neurodegeneration and inflammation. The epigallocatechin gallate (EGCG), a major compound of green tea, is recognized as protective substance against neuronal diseases. This study is aimed to investigate the effect of EGCG on NO-induced cell death in PC12 cells. Administration of sodium nitroprusside (SNP), a NO donor, decreased cell viability in a dose- and time-dependent manner and induced genomic DNA fragmentation with cell shrinkage and chromatin condensation. EGCG diminished the decrement of cell viability and the formation of apoptotic morphologenic changes as well as DNA fragmentation by SNP. EGCG played as an antioxidant that attenuated the production of reactive oxygen species (ROS) by SNP. The cells treated with SNP showed downregulation of Bcl-2, but upregulation of Bax. EGCG ameliorated the altered expression of Bcl-2 and Bax by SNP. The release of cytochrome c from mitochondria into cytosol and expression of voltage -dependent anion channel (VDAC)1, a cytochrome c releasing channel in mitochondria, were increased in SNP-treated cells, whereas were attenuated by EGCG. The enhancement of caspase-9, preceding mitochondria-dependent pathway, caspase-8 and death receptor-dependent pathway, as well as caspase-3 activities were suppressed by EGCG. SNP upragulated Fas and Fas-L, which are death receptor assembly, whereas EGCG ameliorated the expression of Fas enhanced by SNP. These results demonstrated that EGCG has a protective effect against SNP-induced apoptosis in PC12 cells, through scavenging ROS and regulating the mitocondria- and death receptor-mediated signal pathway. The present study suggest that EGCG might be a natural neuroprotective substance.

• Journal of Periodontal and Implant Science
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• 제42권6호
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• pp.185-195
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• 2012

Purpose: (-)-epigallocatechin-3-gallate (EGCG) has been reported to exert anti-inflammatory and antibacterial effects in periodontitis. However, its exact mechanism of action has yet to be determined. The present in vitro study evaluated the anti-in-flammatory effects of EGCG on human periodontal ligament fibroblasts (hPDLFs) and human periodontal ligament stem cells (hPDLSCs) affected by bacterial lipopolysaccharide (LPS) extracted from Porphyromonas gingivalis. Methods: hPDLFs and hPDLSCs were extracted from healthy young adults and were treated with EGCG and/or P. gingivalis LPS. After 1, 3, 5, and 7 days from treatment, cytotoxic and proliferative effects were evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and bromodeoxyuridine assay, respectively. And then, the gene expressions of hPDLFs and hPDLSCs were observed for interleukin (IL)-$1{\beta}$, IL-6, tumor necrosis factor (TNF)-${\alpha}$, osteoprotegerin (OPG), receptor activator of nuclear factor kappa-B ligand (RANKL), and RANKL/OPG using real-time polymerase chain reaction (PCR) at 0, 6, 24, and 48 hours after treatment. The experiments were performed with the following groups for hPDLFs and hPDLSCs; 1) No treat, 2) EGCG alone, 3) P. gingivalis LPS alone, 4) EGCG+P. gingivalis LPS. Results: The 20 ${\mu}M$ of EGCG and 20 ${\mu}g/mL$ of P. gingivalis LPS had the lowest cytotoxic effects, so those concentrations were used for further experiments. The proliferations of hPDLFs and hPDLSCs increased in all groups, though the 'EGCG alone' showed less increase. In real-time PCR, the hPDLFs and hPDLSCs of 'EGCG alone' showed similar gene expressions to those cells of 'no treat'. The gene expressions of 'P. gingivalis LPS alone' in both hPDLFs and hPDLSCs were highly increased at 6 hours for IL-$1{\beta}$, IL-6, TNF-${\alpha}$, RANKL, and RANKL/OPG, except the RANKL/OPG in hPDLSCs. However, those increased gene expressions were down-regulated in 'EGCG+P. gingivalis LPS' by the additional treatment of EGCG. Conclusions: Our results demonstrate that EGCG could exert an anti-inflammatory effect in hPDLFs and hPDLSCs against a major pathogen of periodontitis, P. gingivalis LPS.