• Natural Product Sciences
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• 제19권2호
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• pp.166-172
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• 2013

Caffeine and epigallocatechin gallate (EGCG) are major constituents of green tea, the leaves of Camellia sinensis (Theaceae). Although EGCG is well known for diverse beneficial effect, caffeine is sometimes harmful with adverse effects. Therefore, the extraction efficiency was investigated using different extraction method such as extraction solvent, extraction time, extraction method, and repeated extraction. The content of EGCG and caffeine in green tea extract was quantitated by HPLC analysis. The extraction condition exerted difference on the extraction yield. The content of EGCG was also affected by different extraction condition. Especially, the extraction solvent greatly affected the content of EGCG in the extract. However, the content of caffeine was less affected compared to that of EGCG. The inhibitory effect of green tea extract on pancreatic lipase was almost similar regardless of extraction condition. Taken together, optimization of extraction condition will provide best efficacy for further development of green tea as anti-obesity therapeutics.

• Journal of Applied Biological Chemistry
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• 제53권1호
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• pp.56-59
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• 2010

An optimal manufacturing process was established for the mass-production of mulberry leaves tea. The produced tea contained abundant dietary fibers, $\beta$-carotenes, and calcium. Also the polyphenol content and antioxidant activity of mulberry leaves tea were higher than those of simply dried mulberry leaves. These results imply that this tea manufacturing process is effective to utilize the useful components of mulberry leaves.

• Preventive Nutrition and Food Science
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• 제14권1호
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• pp.49-53
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• 2009

Antioxidative activities of major pentacyclic terpenoids from the semi-fermented tea of Camellia sinensis L. were investigated. The free radical scavenging activities of triterpenoids $1{\sim}3$ were examined with of DPPH and superoxide anion radical scavenging activity. The $IC_{50}$ of compounds 1 and 2 for DPPH radical scavenging activities were 23.1 and $37.2{\mu}g/mL$ respectively, and for superoxide anion radical scavenging activities were 37.2 and $35.2{\mu}g/mL$, respectively. According to this result, compounds 1 or 2 in semi-fermented tea could be the candidates for bioactive material having antioxidant activity.

• 한국환경성돌연변이발암원학회지
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• 제25권2호
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• pp.71-75
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• 2005

Green tea and their major constituents such as catechins are famous materials for their anti-oxidative and anti-carcinogenic activity, but many compounds with reducing power can promote the oxidation in their oxidized form or in the presence of metal ion. We investigated the pro-oxidative effect of the ethanol extract equivalent up to 30mg of dried weight of green tea leaves in four in vitro systems which could be used for detecting DNA damage. Although ethanol extract of green tea did not show significant mutagenicity in Salmonella typhimurium TA102, which is sensitive strain to oxidative stress, it degraded deoxyribose extensively in the presence of $FeCl_3-EDTA$ complex, promoted 8-oxoguanine formation in the live bacteria cell, Salmonella typhimurium TAI04, and cleaved super coiled DNA strand with the help of copper ion. It suggested that green tea, famous anti-oxidative material, can be pro-oxidant according to the condition of extraction or metal existence.

• 대한의생명과학회지
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• 제16권4호
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• pp.265-269
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• 2010

Puer tea is a traditional beverage originating from Yunnan area of China. We have analyzed 11 different commercial tea brands provided by Daboo Culture and Art Center. This study was carried out to evaluate the contents of polyphenols, antibacterial activity, antioxidantive ability and physiological activities of extracts from Puer tea. The electron donating ability was ranged from 57.26~99.16% and SOD-like activity was ranged from 1.4~10.4%. The inhibitory effect on the growth of cancer cell lines was examined by MIT assay. The Puer tea extract exhibited the greatest inhibitory effect at the concentration of 2% for all cancer cells tested.

• Journal of Preventive Medicine and Public Health
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• 제43권4호
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• pp.366-367
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• 2010

Green tea is a popular beverage and its health benefits are well known. However, inconsistent results have been reported in observational studies concerning the association between green tea consumption and the lung cancer risk. In this commentary, several methodological issues underlying the measurement of tea exposure are highlighted. The recommendations should be useful for designing and planning prospective cohort studies to ascertain the protective effect of green tea against lung cancer.

• 분석과학
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• 제8권4호
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• pp.877-880
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• 1995

The determination of fluoride and the nutritious calcium in infusion of teas are explained. Tea leaves were pulverized and were immersed in boiling water. The solution was filtered and fluoride, calcium and oxalic acid were determined by the ion chromatography. The quantities of fluoride, calcium and oxalate ions extracted from 100 g of tea leaves were calculated. Tea leaves were also immersed in 0.5 M hydrochloric acid and extracted oxalate and calcium ions were analyzed. The free oxalic acid and calcium were extracted in boiling water and the total ones were extracted in hydrochloric acid. The quantity of calcium oxalate was calculated from the total and the free oxalic acids. The free calcium was estimated to be nutritious.

• 운동영양학회지
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• 제13권2호
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• pp.141-145
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• 2009

The purpose of this study was to investigate the effect of endurance training and Rooibos-tea treatment during 12 week on lipid peroxidation(MDA), oxidative DNA damage(8-hydroxyguanine), and antioxidant enzymes(SOD, GPX) in human. The subjects were divided into three groups; Train+Rooi, Train, and Rooi groups. The Train+Rooi and Rooi group took 3 g of Rooibos-tea for 12 weeks. Blood samples were taken from antecubital vein at before training, after 6week, and after 12 week training. Data were analyzed by two-way ANOVA with repeated measures using the SPSS/PC⁺. The results are summarized as follows: MDA and 8-hydroxyguanine concentration were no significantly differences between group(p>.05). SOD and GPX concentration were significantly increased in Train+Rooi, Rooi group than Train group(p<.05). This results suggested that effects of Rooibos-tea treatment has associated with improve scavenger of antioxidant.

• Bulletin of the Korean Chemical Society
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• 제23권9호
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• pp.1229-1258
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• 2002

This paper reports the photochemical reduction of benzil 1 to benzoin 2 and the reduction of 2 to hydrobenzoin 4 in deoxygenated solvents in the presence of triethylamine (TEA) and/or TiO2. Without TEA or TiO2, the photolysis of 1 resulted in very low yield of 2. The presence of TEA or TiO2 increased the rate of disappearance of 1 and the yield of 2, which were further increased considerably by the presence of water. The photoreduction of 1 to 2 proceeds through an electron transfer to 1 from TEA or hole-scavenged excited TiO2 followed by protonation. In the reaction medium of 88 : 7 : 2 : 3 CH3CN/CH3OH/H2O/TEA with 2.5 $㎎/m{\ell}$ of TiO2, the yield of 2 was as high as 85 % at 50 % conversion of 1. The photolysis of 2 in homogeneous media resulted in photo-cleavage to benzoyl and hydroxybenzyl radicals, which are mostly converted to benzaldehyde. The reduction product 4 is formed in low yield through the dimerization of hydroxybenzyl radicals. The addition of TEA increased the conversion rate of 2 and the yield of 4 significantly. This was attributed to the scavenging effect of TEA for benzoyl radical to produce N,N-diethylbenzamide and the photoreduction of benzaldehyde in the presence of TEA. The ratio of $(\pm)$ and meso isomers of 4 obtained from the photochemical reaction is about 1.1. This ratio is the same as that from the photochemical reduction of benzaldehyde in the presence of TEA. In the TiO2-sensitized photochemical reduction of 2, meso-4 was obtained in moderate yield. The reduction of 2 to 4 proceeds through two consecutive electron/proton transfer processes on the surface of the photocatalyst without involvement of ${\alpha}-cleavage$. The radical 11 initially formed from 2 by one electron/proton process can also combine with hydroxy methyl radical, which is generated after hole trapping of excited TiO2 by methanol, to produce 1,2-diphenylpropenone after dehydration reaction.

• 한국식품영양과학회지
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• 제39권12호
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• pp.1807-1813
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• 2010

안전성이 확보된 후발효차를 제조하기 위해 Bacillus subtilis, Saccharomyces cerevisiae 및 Lactobacillus bulgaricus를 이용하여 후발효차를 제조한 후 발효 시간에 따른 화학성분의 변화와 관능적 기호도의 변화를 측정하였다. 발효 진행 정도에 따른 색상변화에서는 lightness는 감소하고 redness와 yellowness는 모두 증가하였으며 특히 B. subtilis에 의한 후발효차 제조 시 가장 많은 수색의 변화를 보였다. Chlorophyll의 함량변화에서는 발효가 진행됨에 따라 균종에 관계없이 모두 비슷한 수준으로 감소하였다. 총 카테킨의 함량변화에서는 B. subtilis균의 발효에 의하여 카테킨의 함량이 가장 많이 감소하는 것으로 나타났으며 발효기간이 증가할수록 유의적으로 낮은 함량을 나타내었다. 그러나 L. bulgaricus균에 의한 발효에서는 카테킨의 함량은 감소하지 않았다. Caffeine 함량변화에서는 모든 발효차에서 발효전의 함량보다는 다소 감소하였지만 많은 함량의 변화는 없는 것으로 나타났다. 발효기간별 관능검사 결과에서는 색, 향, 맛 및 종합적 기호도 모두 B. subtilis를 이용한 후발효차가 가장 우수한 것으로 나타났다.