• Food Science and Biotechnology
• /
• 제18권5호
• /
• pp.1212-1217
• /
• 2009

This study examined the influence of manufacturing processes and extraction conditions on the chemical compositions of green tea. Green tea samples grown in various areas (Korea, China, and Japan) and processed by 4 different methods (steaming, pan-firing, steaming and pan-firing, and heavy roasting after steaming and pan-firing) were collected for study. The chemical compositions of the green tea extracts and infusions were different according to their processing methods and extraction conditions, including catechins, caffeine, and free amino acids contents. In all samples analyzed, (-)-epigallocatechin gallate (EGCG), (-)-epigallocatechin (EGC), and theanine were determined as the major catechins and free amino acid, respectively. Studies of samples grown in the same area (Jeju; Korea) showed that there were significant differences in the concentrations of catechins and caffeine in extract and infusion according to the processing methods. These results indicate that processing methods influenced the chemical compositions of the green tea extracts and infusions.

• Archives of Pharmacal Research
• /
• 제28권5호
• /
• pp.573-581
• /
• 2005

Flavonoids, a group of low molecular weight phenylbenzopyrones, have various pharmacological properties including antioxidant activity, anticancer, and immunomodulatory effects. In the present study, lipopolysaccharide (LPS) and phorbol 12-myristate 13-acetate/phytohemagglutinin (PMA/PHA) were used as stimulants for RAW 264.7 macrophages and human peripheral blood mononuclear cell (hPBMC), and tumor necrosis factor (TNF)-${\alpha}$ and interleukin (IL)-2 productions were measured. In addition, flavonoids were examined for their effects on LPS-induced NO production in RAW 264.7 macrophages. The results showed that all compounds were not strongly cytotoxic at the tested concentrations on hPBMC and RAW 264.7 macrophages. On immunomodulatory properties, catechin, epigallocatechin (EGC), naringenin, and fisetin repressed NO production and TNF-${\alpha}$ secretion. Furthermore, catechin, epigallocatechin gallate (EGCG), epicatechin (EC), luteolin, chrysin, quercetin, and galangin increased IL-2 secretion while EGC, apigenin, and fisetin inhibited the secretion. These results indicated that flavonoids have the capacity to modulate the immune response and have a potential anti-inflammatory activity. There was no obvious structure-activity relationship regard to the chemical composition of the flavonoids and their cell biological effects.

• Food Science and Biotechnology
• /
• 제17권3호
• /
• pp.464-469
• /
• 2008

In human beings, it is known that there is a correlation between the occurrence of acne and the ability to suppress sebum. Sebosuppression may be related to the inhibition of sebocyte proliferation, differentiation, and lipogenesis in sebaceous glands. To investigate the skin sebosuppressive activity of green tea extract, the in vivo effects of its flavonoid compounds on the androgen-dependent stimulation of pigmented macules in hamsters and performed in vitro experiments with human primary sebocytes were examined. Our results imply a dual activity of skin sebosuppression by green tea flavonoids; some catechins including epigallocatechin-3-gallate (EGCG) and gallocatechin-3-gallate (GCG) may reduce the differentiation of sebocytes by inhibiting PPAR-${\gamma}1$ mRNA expression, whereas some flavonol glycosides including kaempferol may inhibit lipogenesis in sebaceous glands by decreasing levels of the mature form of sterol-sensitive response elements binding protein-1c (SREBP-1c). Therefore, green tea is a potentially effective material for use in the development of health foods or cosmetics for skin sebosuppression.

• Bulletin of the Korean Chemical Society
• /
• 제29권8호
• /
• pp.1549-1553
• /
• 2008

A molecular imprinted polymer (MIP) using (+)catechin ((+)C) as a template and acrylamide (AM) as a functional monomer was prepared. Acetonitrile was used as the porogen with ethylene glycol dimethacrylate (EGDMA) as the crosslinker and 2,2'-azobis(isobutyronitrile) (AIBN) as the initiator. The adsorption isotherms in the MIP were measured and the parameters of the equilibrium isotherms were estimated by linear and nonlinear regression analyses. The linear equation for original concentration and adsorpted concentrations was then expressed, and the adsorption equilibrium data were correlated into Langmuir, Freundlich, quadratic, and Langmuir Extension isotherm models. The mixture compounds of (+)C and epicatechin (EC) show competitive adsorption on specific binding sites of the (+)catechin-MIP. The adsorption concentrations of (+)C, epicatechin (EC), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG), on the (+)catechin-molecular imprinted polymer were compared. Through the analysis, the (+)catechin-molecular imprinted polymer showed higher adsorption ability than blank polymer which was synthesized molecular imprinted polymer without (+)catechin. Furthermore, the competitive Langmuir isotherms were applied to the mixture compounds of (+)C and EC.

• Natural Product Sciences
• /
• 제23권4호
• /
• pp.274-280
• /
• 2017

In a search for novel treatments for diabetic complications from natural resources, we found that the ethyl acetate-soluble fraction from the 80% ethanol extract of the leaves of Homonoia riparia has a considerable inhibitory effect on advanced glycation end product (AGE) formation. Bioassay-guided isolation of this fraction resulted in identification of 15 phenolic compounds (1 - 15). These compounds were evaluated in vitro for inhibitory activity against the formation of AGE. The majority of tested compounds, excluding ethyl gallate (15), markedly inhibited AGE formation, with $IC_{50}$ values of $2.2-89.9{\mu}M$, compared with that of the positive control, aminoguanidine ($IC_{50}=962.3{\mu}M$). In addition, the effects of active isolates on the dilation of hyaloid-retinal vessels induced by high glucose (HG) in larval zebrafish was investigated; (-)-epigallocatechin-3-O-gallate (6), corilagin (7), and desmanthine-2 (11) significantly decreased HG-induced dilation of hyaloid-retinal vessels compared with the HG-treated control group.

• Biomolecules & Therapeutics
• /
• 제11권4호
• /
• pp.238-244
• /
• 2003

Nicotine is one of the major hazardous components in cigarettc smoke. Nicotine deals a harmful effect to smokers and passive smokers due to its rapid conversion to various carcinogenic metabolites. Nitrosamine-4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is believed to cause lung cancers among the nicotine-derived carcinogens. Recent studies report that NNK synthesis can be inhibited by the metabolism pathway to produce a stable metabolite cotinine from nicotine. Tea polyphenols have been known to contain factors to prevent cancers and to retard progression of cancers. This study aims to correlate tea polyphenol's potential for cancer prevention with an accelerated formation of cotinine. The conversion from nicotine to cotinine in the presence of tea extracts or three polyphenols (Catechin, epicatechin gallate, epigallocatechin gallate) was measured in established cell lines and in Xenopus oocytes. Among three lines of cell used, PLC/PRF5 and HEK293 cells showed a fast turnover from nicotine to cotinine while HepG2 cell line showed a marginal difference between groups treated and non-treated with tea polyphenols. When Xenopus oocytes were microinjected with nicotine, tea polyphenols appear to accelerate the conversion of nicotine to cotinine. Among the polyphenols tested in this study, (＋)－catechin showed the best efficiency overall in accelerating conversion from nicotine to cotinine both in the cell lines and in the oocytes. In summary, the present study indicated that tea polyphenols have a positive effect on conversion of nicotine to cotinine.

• Integrative Medicine Research
• /
• 제3권1호
• /
• pp.25-33
• /
• 2014

Background: Green tea contains numerous polyphenols, which have health-promoting effects. The purpose of this study was to evaluate the effect of tannase-converted green tea extract (TGE) formulation on the physical stability and activities of skin-related enzymes. Methods: Physical stability was evaluated by measuring the pH, precipitation, and colors at $25{\pm}2^{\circ}C$ /ambient humidity and at $40{\pm}2^{\circ}C$ \70%${\pm}$5% relative humidity for 4 months. Activities of collagenase, elastase, and tyrosinase as skin-related enzymes were assessed on TGE formulation. Results: The concentrations of epigallocatechin-3-gallate and epicatechin-3-gallate in green tea extract were greatly decreased to the extent of negligible level when treated with tannase. The formulation containing 5% tannase-converted green tea extract showed relatively stable pH, precipitation, and color features for 16 weeks. When TGE was added to the formulation, there was a significant increase in the inhibition of elastase and tyrosinase activities (p<0.05) compared with the formulation containing 5% normal green tea extract. Conclusion: The TGE could be used in cosmetics as skin antiwrinkling or depigmenting agent.

• 한국안광학회지
• /
• 제18권4호
• /
• pp.525-531
• /
• 2013

목적: 점안마취제 성분인 proparacaine hydrochloride (PPC)에 의한 결막세포주의 세포자연사와 이에 대한 epigallocatechingallate(EGCG)의 보호효과를 알아보고자 하였다. 방법: 동일한 조건으로 배양된 결막세포주에 Alcaine$^{(R)}$ 0.5%, PPC 0.5%, 그리고 0.01% benzalkonium chloride (BAC)을 각각 15분간 처리한 후, 추가적으로 12시간과 24시간 배양한 후 세 군으로 나누어 MTT assay와 LDH assay를 실시하였다. 배양된 결막세포주에 EGCG를 $10{\mu}M$의 농도로 3시간 동안 전 처리한 후 0.5% PPC를 15분간 추가 배양한 다음 유세포분석기를 이용한 세포자연사 정도를 측정하였다. 결과: Alcaine$^{(R)}$ 0.5%, PPC 0.5%, BAC 0.01%를 15분 동안 처리한 직후와 다시 12시간과 24시간 추가 배양한 결과 모든 군에서 세포생존율이 증가하지 않았다(p<0.05). 0.5% PPC 단독처리군($32.2{\pm}2.0%$)에 비해 $10{\mu}M$의 EGCG 3시간 전 처리하고 PPC 0.5% 후 처리한 군(68.2%)에서 세포 생존율은 더 높아졌다. 또한 PPC 0.5% 처리한 군에서 유도된 세포자연사는 EGCG 첨가로 감소되었다. 결론: 점안마취제인 PPC에 EGCG를 전처리함으로써 세포생존율을 증가시키고, 세포자연사를 억제함으로서 EGCG는 세포보호 효과가 있는 것으로 나타났다.

• 한국식품저장유통학회지
• /
• 제16권6호
• /
• pp.946-952
• /
• 2009

추출조건을 달리하여 제조한 녹차음료의 이화학적 특성 및 항산화활성에 대하여 조사하였다. 녹차음료 1, 2 및 시판 녹차음료의 pH는 각각 6.22, 6.39 및 6.20이었고, 색도 L, a 및 b값은 각각 96.91, -1.06, 7.77, 96.20, -1.73, 13.68 및 95.40, -4.75, 25.51이었다. 녹차음료 1, 2 및 시판 녹차음료의 총유리아미노산 함량은 253.21, 262.65 및 58.36 mg/100 mL이었고, 주요 유리아미노산으로는 aminoadipic acid(102.56, 136.29 및 27.02 mg/100 mL), arginine (23.32, 30.75 및 7.31 mg/100 mL) 및 serine (18.22, 17.96 및 5.94 mg/100 mL)이었다. 녹차음료 1, 2 및 시판 녹차음료의 총 페놀성화합물 및 카페인 함량은 각각 500.65와 317.34, 852.58과 225.51 및 387.14와 $164.53\;{\mu}g/mL$로 녹차음료 2가 높았다. 녹차음료 1, 2 및 시판 녹차음료의 총카테킨함량은 각각 294.80, 415.70 및 $130.99\;{\mu}g/mL$이었고, 주요 카테킨으로는 epigallocatechin, catechin 및 epigallocatechin gallate 순이었으며, epigallocatechin의 함량이 각각 186.5, 268.1 및 $82.26\;{\mu}g/mL$로 가장 많은 함량을 보였다. 녹차음료 1, 2 및 시판 녹차음료 동결건조물의 항산화 활성은 농도 의존적이었으며, 농도 $125\;{\mu}g/mL$에서 DPPH 라디칼 소거활성은 각각 85.48%, 87.09% 및 87.03%였고, ferric reducing/antioxidant activity는 농도 $1,000\;{\mu}g/mL$에서 2.66, 2.70 및 2.67이었다. 또한 쓴맛을 제외한 색, 향, 단맛 및 전체적인 기호도와 같은 관능검사결과 녹차음료 1, 2 및 시판녹차음료에서 큰 유의적인 차이를 보이지 않았다.

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