• KSBB Journal
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• v.14 no.5
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• pp.517-522
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• 1999

A green tea used in this experiment was cultivated at Bosung (Chonnam) and purchased from a domestic market. The extract at 5$0^{\circ}C$ water from the powder of green tea partitioned with chloroform and ethyl acetate. The resulting solution was further purified with a chromatographic column (4.6$\times$250 mm, 15${\mu}{\textrm}{m}$, Lichrospher 100RP-18). Finally separation was achieved on a $\mu$-Bondapak $C_18$(3.9$\times$300mm, 10${\mu}{\textrm}{m}$) column. The elution order of the catechin compounds contained in the green tea was EGC(Epigallocatechin, C(catechin), EC(Epicatechin), EGCG(Epigallocatechin Gallate) and ECG(Epicatechin Gallate). From the experimental results the mobile phase for isolating EGCG from the extract consisted of 0.1% acetic acid in water/acetonitrile, 87/13%(v/v). The flow rate of mobile phase was 1.0 $m\ell$/min, and UV wavelength was fixed at 280 nm. 121.3 mg of EGCG, higher than 98% of purity, was obtained from 5 g of dry green tea.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.167-170
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• 2007

(-)-Epigallocatechin-3-gallate (EGCG), a mai or tea catechin has been shown to have many interesting biological activities. In the present study, we studied the effects of green tea catechins, EGCG metabolites, and black tea theaflavins on accumulation of EGCG in HT-29 human colon cells. Intracellular levels of [$^3H$]-EGCG were not changed significantly in the presence of other tea catechins including (-)-epicatechin, (-)-epigallocatechin, and (-)-epicatechin-3-gallate. EGCG methyl metabolites and EGCG 4"-glucuronide did not affect cellular levels of [$^3H$]-EGCG. Black tea theaflavins and theasinensin A (TsA), an EGCG oxidative dimer, however, significantly decreased cellular accumulation of EGCG in HT-29 cells by 31-56%. This decrease was more pronounced when cells were incubated in the presence of theaflavin-3',3"-digallate (TFdiG) or TsA. When EGCG was added separately from TFdiG or TsA, the accumulation of EGCG in HT-29 cells was also significantly decreased regardless of when TFdiG or TsA was added during the uptake study (p<0.01). The results suggest that theaflavins and TsA may interrupt EGCG absorption through the gastrointestinal epithelium.

• Journal of Nutrition and Health
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• v.36 no.4
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• pp.382-388
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• 2003

(-)-Epigallocatechin-3-gallate (EGCG) is a polyphenolic compound found in peen tea leaves, and has been known to be one of the most potent catechin species which inhibits cell growth most possibly through an apoptotic cell death. We investigated the apoptotic activity of (-)-EGCG on the human myeloid leukemia cell line, HL-60. Our results of MTT test indicated that (-)-EGCG had a significant antiproliferation effect in HL-60 cells with $IC_{50}$/ (50% inhibition concentration) value of 65 $\mu$M. Giemsa statining of HL-60 cells treated with (-)-EGCG (100 $\mu$M) for 6hrs showed a typical apoptosis-specific morphological change including shrinkage of the cytoplasm, membrane blobbing and compaction of the nuclear chromatin. The DNA fragmentation was observed from the agarose gel electrophoresis of cells treated with (-)-EGCG for 3hrs or longer, and was progressed to a greater degree as treatment time increases. Treatment of the cells with (-)-EGCG (100 $\mu$M) resulted in a rapid release of mitochondrial cytochrome c into the cytosol, and a subsequent cleavage of caspase-3 to an active form in a treatment-time dependent manner. (-)-EGCG (100 $\mu$M) also stimulated proteolytic cleavage of poly-(ADP-ribose) polymerase (PARP) to an active form in HL-60 cells. Tlken together, (-)-EGCG appears to induce the apoptosis in human myeloid leukemia cells via a caspase-dependent pathway. These results suggest the possible application of (-)-EGCG, the major active compound in green tea, as an antiproliferative agent for cancer prevention.

• Environmental Mutagens and Carcinogens
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• v.18 no.2
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• pp.98-103
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• 1998

Epigallocatechin gallate (EGCG) was reported to exert weak cytotoxicity against normal healthy cells such as C3H10T1/2 cells, but profound inhibitory effects on the initiation or promotion stage of chemical carcinogenesis in mammary gland, blood and mouse skin. This study was carried out to develop antitumor agents with weak side effects and strong antitumor activity. Human skin melanoma cells (HBT 69) and human oral epitheloid carcinoma cells (OCL 17) were cultured in RPMI-1640 media containing 10% fetal bovine serum, antibiotic, and fungizone. After incubation for 24 hrs, the cells were treated with various amounts of (EGCG) for 48 hrs. The growth inhibitory effects of EGCG in human oral epitheloid carcinoma cells were evaluated by the 3- (4,5-djmethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), neutral red (NR), and sulforhodamine B protein (SRB) assays of colorimetric methods. The light microscopic study was also carried out to observe morphological changes of the treated cells. These results obtained were as follows; 1. Significantly inhibitory effects of EGCG against cultured human oral epithelioid carcinoma cells. 2. Significantly inhibitory effects against cultured human skin melanoma cells treated with 50 $\mu$M EGCG, but decreased inhibitory effects in 100 $\mu$M EGCG. 3. Degenerative changes against cultured human oral epitheloid carcinoma cells. 4. Degenerative changes against human skin melanoma cells treated with 50 UM EGCG, but recovered degenerative changes in 100 $\mu$M EGCG.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.855-862
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• 2012

Resveratrol (RVT) and epigallocatechin gallate (EGCG) individually inhibit adipogenesis in 3T3-L1 adipocytes. The objective was to examine the possibility of interaction between RVT and EGCG, resulting in enhanced inhibition of adipogenesis in 3T3-L1 adipocytes. Preadipocytes were treated with RVT and EGCG individually at 6.25 or $25{\mu}M$ (RVT6.25 or RVT25) and 12.5 or $50{\mu}M$ (EGCG12.5 or EGCG50) and in combination (RVT6.25 + EGCG12.5 and RVT25 + EGCG50). RVT25 as an individual compound decreased lipid accumulation in 3T3-L1 adipocytes by 24%, and RVT25 + EGCG50 further decreased lipid accumulation by 77%. In addition, exposure of 3T3-L1 adipocytes to RVT6.25 + EGCG12.5 and RVT25 + EGCG50 combinations resulted in an enhanced increase of adiponectin release and inhibition of leptin release. Quantitative analysis revealed that the combination of tested materials (RVT6.25 + EGCG12.5 and RVT25 + EGCG50) decreased the expression levels of C/EBP${\alpha}$, PPAR${\gamma}2$, and aP2. These results indicate that the combined treatments with RVT and EGCG produce synergistic effects on inhibiting adipogenesis in 3T3-L1 adipocytes. The overall results suggested that the combining RVT and EGCG might be more capable of exerting antiobesity effects than each individual compound by itself.

• Journal of Pharmaceutical Investigation
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• v.29 no.3
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• pp.179-184
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• 1999

Phannacokinetics of epigallocatechin gallate(EGCG) was studied following i.v. bolus and oral administration in rats. The values of systemic clearance(CL) were $67.9{\pm}5.2$ and $26.5{\pm}1.4\;ml/min/kg$ following i.v. bolus administration of 1 mg and 5 mg EGCG, respectively. The values of volume of distribution at steady state (Vss) were $380{\pm}56$ and $835{\pm}84\;ml/kg$ after i.v. bolus administration of 1 mg and 5 mg EGCG, respectively. The decrease in the value of CL and the increase in the value of $V_{ss}$ as a function of EGCG dose (1 mg to 5 mg) suggest saturable mechanism(s) responsible for the distribution and elimination of EGCG. The fraction absorbed of EGCG after oral and intraduodenal administration of GTC were 13% and 22% of the dose, respectively. This result suggests a considerable degradation or elimination of EGCG in the gastrointestinal absorption after oral administration in rats.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.9
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• pp.1114-1119
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• 2008

Among the numerous polyphenols isolated from green tea, epigallocatechin gallate (EGCG) is a predominate and is considered to be a major therapeutic agent. To elucidate the mechanical insights of anti-tumor effect, EGCG was applied to human breast cancer MDA-MB-231 cells. We investigated the effect of EGCG on protein and mRNA expression of proteins related to cell apoptosis in MDA-MB-231 human breast cancer cell lines. We also identified caspase-3 activity. We cultured MDA-MB-231 cells in the presence of 0, 5, 10, and $20\;{\mu}M$ of EGCG. Protein and mRNA expression of bcl-2 were decreased dose-dependently in cells treated with EGCG. However, protein and mRNA expression of bax were increased (p<0.05). Caspase-3 activities were increased dose-dependently in cells treated with EGCG. These results suggest that EGCG induces cell apoptosis by increase of caspase activity through decreasing of protein and mRNA expression of bcl-2 and increasing of protein and mRNA expression of bax.

• The Korean Journal of Food And Nutrition
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• v.30 no.5
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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.

• Korean Journal of Pharmacognosy
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• v.32 no.4 s.127
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• pp.280-286
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• 2001

Epigallocathechin-3-gallate (EGCG), the main polyphenol component in green tea, inhibits angiogenesis, urokinase, and matalloproteinases, and EGCG also has the antioxidative property. Recent reports proposed that EGCG may modulate the immune response on allergy or asthma. Human nasal mucosal fibroblasts are a rich source of cytokines, inflammatory mediators, and chemokines. Chemokines are important for the recruitment of leukocytes to sites of infection, which is essential in host defense. The objective of this study was to investigate the effect of EGCG on the expression of the chemokines such as RANTES (regulated upon activation, normal T cell expressed and presumably secreted), eotaxin, and interleukin-8 (IL-8) in human nasal mucosal fibroblasts after stimulation with cytokines like IL-4, tumor necrosis $factor-{\alpha}\;(TNF-{\alpha})$, and $interferon-{\gamma}\;(IFN-{\gamma})$. To detect the expression of chemokine genes, RT-PCR was performed. Expressions of RANTES, eotaxin, and IL-8 mRNA stimulated with IL-4 and $TNF-{\alpha}$ were increased, respectively, while the expression of those genes incubated with $IFN-{\gamma}$ was similar pattern compared to control group. Analyses of chemokine genes of cells pretreated with EGCG showed that the expressions of eotaxin, and IL-8 genes stimulated $IFN-{\gamma}$ were higher compared with those not pretreated with EGCG.

• Journal of Food Hygiene and Safety
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• v.17 no.3
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• pp.117-123
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• 2002

The five main green tea catechin components such as (+)-catechin, (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate, and (-)-epigallocatechin gallate were analyzed quantitatively from commercial green tea by HPLC. Amounts of catechins decreased in the following order : (+)-catechin > (-)-epigallocatechin gallate >(-)-epigallocatechin >(-)-epicatechin >(-)-epicatechin gallate. In this study, the stability of the following green tea catechins to pH in the range from 3 to 11 was studied using of ultraviolet spectroscopy : (+)-catechin, (-)-epicatechin, (-)-epicatechin gallate, and (-)-epigallocatechin gallate. This study demonstrated that green tea catechins were not stable at high pH and that the pH-, and time-dependent spectral alternatives were not reversible In conclusion, low pH is important to maintain the efficient utilization of green tea catechins.