• The Korean Journal of Food And Nutrition
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• v.27 no.2
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• pp.267-273
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• 2014

This study found antibacterial activity of $DMfree^{(R)}$ [green tea extract] on facultative bacteria by direct petri dish method and gene array of obligatory M. leprae infected mesenchymal stem cells (MSC). While DMfree showed DPPH radical scavenging effect and high contents of polyphenol, it did not inhibit growth of facultative bacteria such as E. coli and S. aureus on the petri dish. The result does not exclude a possible antibacterial effect of organic solvent extract of green tea rather than DMfree which comes from the water extract of green tea. Pre-treatment of DMfree appeared to have no effect on copy number of 14 genes compared with control MSC by real-time RT-PCR. However pre-treatment of DMfree on M. leprae infected MSC revealed a significant decrease of anti-inflammatory cytokine (IL-6), (P<0.038) and sharp down-regulation of pro-inflammatory cytokine (IL-1). Enhanced expression of VEGFR-1 mRNA was noted in DMfree pretreated M. leprae infected MSC group (P<0.003). These results show that DMfree would stabilize M. leprae infected MSC from further inflammation by down-regulating anti-inflammatory cytokine (IL-6) and pro-inflammatory cytokine (IL-$1{\beta}$). This is the first report on DMfree inhibition of IL-6 and IL-$1{\beta}$ expression in M. leprae infected MSC. Further experiments that detect protein levels of IL-$1{\beta}$ and IL-6 may support the result of this gene array.

• Food Science and Preservation
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• v.7 no.3
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• pp.249-255
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• 2000

Soybean curd has been known as one of the most favorite traditional Korean foods as well as being high in protein. Each concentration of added natural materials soybean curds was chosen as 4% of carrot, 10% of cucumber, 1.0% of spinach and 0.05% of green tea powder. The yield of soybean curd containing natural materials was similar to that of non-containing curd. According to add GDL as coagulant, the yield of soybean curd containing natural materials was the highest. The turbidity of added natural material soybean curds was the highest coagulated with $CaCl_2$, but soybean curd containing green tea had the highest turbidity in the coagulated with GDL. In the chromaticity and texture properties of the additive natural materials in yhe soybean curd, the variety of additives had no effect. In the composition of natural materials, the carotenoid and chlorophyll content of soybean curds were high with $MgCl_2$ and $CaCl_2$ but polyphenol was high use of $CaSo_4$ and GDL.

• Archives of Pharmacal Research
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• v.23 no.6
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• pp.605-612
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• 2000

Green tea polyphenols (GTP) have been demonstrated to suppress tumorigenesis in several chemical-induced animal carcinogenesis models, and predicted as promising chemopreventive agents in human. Recent studies of GTP extracts showed the involvement of mitogen-activated protein kinases (MAPKs) in the regulation of Phase II enzymes gene expression and induction of apoptosis. In the current work we compared the biological actions of five green tea catechins: (1) induction of ARE reporter gene, (2) activation of MAP kinases, (3) cytotoxicity in human hepatoma HepG2-C8 cells, and (4) caspase activation in human cervical squamous carcinoma HeLa cells. For the induction of phase IIgene assay, (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate (ECG) potently induced antioxidant response element (ARE)-mediated luciferase activity, with induction observed at 25 $\mu\textrm{m}$with EGCG. The induction of ARE reporter gene appears to be structurally related to the 3-gallate group. Comparing the activation of MAPK by the five polyphenols, only EGCG showed potent activation of all three MAPKs (ERK, JNK and p38) in a dose- and time-dependent manner, whereas EGC activated ERK and p38. In the concentration range of 25 $\mu\textrm{m}$ to 1 mM, EGCG and ECG strongly suppressed HepG2-ARE-C8 cell-growth. To elucidate the mechanisms of green tea polyphenol-induced apoptosis, we measured the activation of an important cell death protein, caspase-3 induced by EGCG, and found that caspase-3 was activated in a dose- and time-dependent manner. Interestingly, the activation of caspase-3 was a relatively late event (peaked at 16 h), whereas activation of MAPKs was much earlier (peaked at 2 h). It is possible, that at low concentrations of EGCG, activation of MAPK leads to ARE-mediated gene expression including phase II detoxifying enzymes. Whereas at higher concentrations of EGCG, sustained activation of MAPKs such as JNK leads to apoptosis. These mechanisms are currently under investigation in our laboratory. As the most abundant catechin in GTP extract, we found that EGCG potently induced ARE-mediated gene expression, activated MAP kinase pathway, stimulated caspase-3 activity, and induced apoptosis. These mechanisms together with others, may contribute to the overall chemopreventive function of EGCG itself as well as the GTP.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.2
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• pp.167-173
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• 2016

This study investigated the effects of green tea polyphenol and vitamin C on type 2 diabetes mellitus by administering polyphenon 60 (P60) and sodium ascorbate (SA) to diabetic rats induced by high fat diet/low-dose streptozotocin. The experimental group was divided into five different groups: non-diabetic control group (NC), diabetes control group (DC), diabetes+P60 group (DM+P60), diabetes+SA group (DM+SA), and diabetes+P60+SA group (DM+P60+SA). P60 and SA were dissolved in 0.1% drinking water. After P60 and SA were administered for 16 weeks, fasting blood glucose, plasma insulin, serum triglyceride, blood urea nitrogen (BUN), and creatinine levels as well as kidney alkaline phosphatase (AP) and ${\gamma}$-glutamyltranspeptidase (GGT) activities were measured. Fasting blood glucose level increased 5-fold in the DC group compared to the NC group. In the DM+P60 group, fasting blood glucose level decreased by 14%. In the DM+P60+SA group, fasting blood glucose level decreased by 28% compared to the DC group, whereas the DM+SA group did not show any significant difference. The homeostasis model assessment for insulin resistance index increased in the DC group and decreased in the DM+P60+SA group compared to the DC group. Serum creatinine level increased in the DC group, but decreased by 17% in the DM+P60 group and by 43% in the DM+P60+SA group compared to the DC group. The serum BUN level increased in the DC group, but decreased by 41% in the DM+P60+SA group compared to the DC group. Kidney GGT and AP activities decreased in the DC group compared to the NC group; however, they were reversed by DM+P60+SA group. These results show that combined administration of both green tea polyphenol and vitamin C had better effects on improving blood glucose level, insulin resistance, serum triglyceride level, and protecting kidneys than administration of either green tea polyphenol or vitamin C alone in the context of type 2 diabetes.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.04a
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• pp.25-27
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• 2008

The optimum extraction conditions of green tea used for a bath were investigated for later application to textile. The extraction was more effective in water and methanol than in ethanol. The optimum extraction temperature was determined as 80$^{\circ}C$ in water and 60$^{\circ}C$ in methanol. The extracts were more stable in acid and neutral conditions than in alkaline region. The UV satbility was better than generally expected. From the analysis of contents of active ingredients, the about 20% of effective catechin was appeared to be contained in the extract solid. The contents of polyphenol is 0.016g in the 0.1g extracts.

• Biomolecules & Therapeutics
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• v.11 no.4
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• pp.238-244
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• 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.

• Food Science and Preservation
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• v.14 no.6
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• pp.709-715
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• 2007

Korean green tea has been claimed to have health-promoting effects, which may be related to the antioxidant activity in vitro. Korean green teas (Woojeon, WJ ; Sejak, SJ ; Jungjak, JJ ; Daejak, DJ) were subjected to different harvested times and yet little research has examined their bioactive compounds. To assess the effect of this different harvested times on nutritional and health-related properties such as Korean green tea polyphenols, flavonoids, theanine and free amino acids, antioxidant activities and radical scavenging activities were determined. Total polyphenols in JJ (37.16 mg/g) was higher than in other products (WJ, 19.55 ; SJ 24.65 ; DJ, 23.28 mg/g). Contents of flavonol and flavone glycosides were the highest at DJ (350.83 mg%) as compared to WJ (220.81), SJ (256.88) and JJ (270.36 mg%). Contents of theanine and total free amino acids were the highest at WJ (14.11, 23.62 mg/g, respectively), but decreased thereafter. Antioxidant activities were higher in JJ and DJ, using the linoleic acid peroxidation, DPPH and ABTS free radical-scavenging activities. However, WJ and SJ had less active antioxidant activity and free radical-scavenging activity. Reducing powers were increased depend on the concentration of extracts. Antioxidant activity and free radical-scavenging activity of JJ and DJ seemed to relate with total polyphenol and flavonoid contents.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.6
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• pp.765-770
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• 2017

Green tea (Camellia sinensis L.) is consumed as a popular beverage worldwide, particularly in Asia. In this study, the effects of green tea powder addition on the antioxidant activities and texture properties of cooked rice were investigated. Texture analysis was carried out by texture profile analysis. Total polyphenols and total flavonoids were determined using spectrophotometric methods, and antioxidative activities were determined based on DPPH and ABTS radical scavenging activities, reducing power, and lipid peroxidation inhibitory activity. Antioxidant contents and antioxidative activities increased with a higher amount of green tea powder. However, there was no difference in texture properties between cooked rice with green tea powder and the control group. In conclusion, addition of green tea powder to cooked rice would be useful to increase antioxidant contents and antioxidative activities without alteration of texture properties.

• Environmental Mutagens and Carcinogens
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• v.26 no.3
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• pp.63-68
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• 2006

There are $10{\sim}30%$ polyphenol and $2{\sim}4%$ caffeine in green tea. Caffeine is a kind of alkaloid containing nitrogen which cause stimulation, impatience, headache, insomnia, low birth weight infant. Because of these negative effect, decaffeined beverage came out and decaffeined coffee already have a big market since 1970s. Having proving the physiologic functions of green tea, high consumption of coffee is shifting to green tea. Because of the carcinogenic effect of the organic solvents, decaffeine processing with supercritical carbon dioxide has industrialized and have an advantage in environment-friendly and minimized flavor loss. Decaffeined green tea using supercritical carbon dioxide is considered to be safe but there are not enough study, We investigated the chromosome aberration test with mammalian cell line, CHL. When the cells were treated with 5000, 2000, 1000 ${\mu}g/ml$ and compared with the negative controls, there were no significant (P>0.05) increased chromosome aberration. Same results was observed when adding S9 mixture or not. As a result, water extract of decaffeined green tea using supercritical carbon dioxide does not induce chromosome aberration.

• Environmental Mutagens and Carcinogens
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• v.26 no.4
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• pp.119-124
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• 2006

There are $10{\sim}30%$ polyphenol and $2{\sim}4%$ caffeine in green tea. Caffeine is a kind of alkaloid containing nitrogen which cause stimulation, impatience, headache, insomnia, low birth weight infant. Because of these negative effect, decaffeined beverage came out and decaffeined coffee already have a big market since 1970s. Having proving the physiologic functions of green tea, high consumption of coffee is shifting to green tea. Because of the carcinogenic effect of the organic solvents, decaffeine processing with supercritical carbon dioxide has industrialized and have an advantage in environment-friendly and minimized flavor loss. Decaffeined green tea using supercritical carbon dioxide is considered to be safe but there are not enough study. We investigated the chromosome aberration test with mammalian cell line, CHL. When the cells were treated with 5000, 2000, 1000 ${\mu}g/ml$ and compared with the negative controls, there were no significant(P>0.05) increased chromosome aberration. Same results was observed when adding S9 mixture or not. As a result, water extract of decaffeined green tea using supercritical carbon dioxide does not induce chromosome aberration.