• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.94-94
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• 2003

Tea is the most popular beverage in the world, especially green tea (Camellia sinensis) is daily taken by Asian people including Japanese. In last two decades, a variety of biological effects of tea components such as antioxidative, antimutagenic, anticarcinogenic, antibacterial and radical scavenging activities on bacteria, cultured cells and mammals have been elucidated.(omitted)

• Archives of Pharmacal Research
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• v.21 no.3
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• pp.348-352
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• 1998

Different bacteria wwere seperated from saliva and teeth of cariogenic patients and identified by a variety of morphological and biochemical tests. Extracts of green tea strongly inhibited Escherichia coli, Streptococcus salivarius and Streptococcus mutans. The antibacterial effect of green and black tea extracts were compared with those of amoxicillin, cephradine and eugenol.

• Journal of Life Science
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• v.10 no.2
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• pp.202-209
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• 2000

The factors affecting chemical composition of green tea (Camellia sinensis L.) during extraction process were temperatures and times. The optimum extraction conditions were measured in relation to the changes of chemical compositions from water extracts of green tea (Camellia sinensis L.) under different extraction temperatures (50, 70, 9$0^{\circ}C$) and extraction times (1, 3, 5 minute). The change of color intensity during browning reaction, flavonoid components, contents of total phenols and hydrogen donating activity (reducing activity for $\alpha$, $\alpha$'-diphenyl-$\beta$ -picryhydrazyl) of water extracts form green tea increased as extraction temperatures increased from 50 to 9$0^{\circ}C$ and extraction times prolonged from 1 to 5 min. The contents of important free sugars such as sucrose and glucose slightly increased as the extraction time was prolonged, while little difference in the content of fructose with the prolonged extraction time. Catechins contents extracted from the commercial steamed green tea were increased at higher temperature and longer extraction time. Epigallocatechin (EGC) extracted from 9$0^{\circ}C$ (extraction time 5 min). presented 99.9 mg/g in highest composition of catechin followed by epigallocatechin gallate (EGCg), epicatechin (EC), epicatechin gallate (ECg). The content of vitamin C extracted from green tea was increased about 2 times as the extraction temperature increased from 50 to 9$0^{\circ}C$ and as the extraction time increased from 1 to 5 min. with exception at 9$0^{\circ}C$(extraction time:5 min) which showed less vitamin C content than 7$0^{\circ}C$(extraction time : 3 min) probably due to possible destruction of vitamin C by high temperature.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2003.10a
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• pp.94-94
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• 2003

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.9
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• pp.1134-1139
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• 2007

This study was conducted to investigate the effects of four kinds of tea (Camellia sinensis) extracts on the antioxidant defense systems as well as the activities of alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) in ethanol administered ICR mice. According to the results, treatment with puerh tea significantly increased the superoxide dismutase activity and glutathion reductase activity in liver. In addition, the group treated with oolong tea exhibited higher superoxide dismutase activity and glutathion reductase activity in serum than those of puerh tea, green tea and black tea treated groups. The oolong tea and puerh tea also reduced malondealdehyde contents in both liver and serum. These results suggested that puerh tea and oolong tea were the most effective against alcohol-induced oxidative damage among the Camellia sinensis teas. On the other hand, in the measurement of alcohol break-down enzyme activities, the group treated with green tea exhibited the highest hepatic ADH and ALDH activities, suggesting that the group treated with green tea might be useful for alcohol down-regulation.

• The Korean Journal of Food And Nutrition
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• v.22 no.2
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• pp.279-285
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• 2009

Antioxidant and antimicrobial efficiency were investigated for: i) water extract of green tea(Camellia sinensis), ii) water extract of middle drying megmoondong(Liriope platyphylla Wang et Tang) and iii) water extract of drying megmoondong. The electron donating ability of the green tea(Camellia sinensis) and drying megmoondong(Liriope platyphylla Wang et Tang) extract were 88 and 79, respectively, while that of the middle drying megmoondong extract showed low levels. The relative inhibitory abilities against lipid peroxidase were: green tea(Camellia sinensis) extract > drying megmoondong(Liriope platyphylla Wang et Tang) extract > middle drying megmoondong extract. The green tea(Camellia sinensis) extract showed the strongest antimicrobial effect against Staphylococcus aureus. The middle drying(Liriope platyphylla Wang et Tang) and drying megmoondong extracts showed no antimicrobial effect against Staphylococcus aureus. The green tea(Camellia sinensis) extract had the strongest antimicrobial effect against Escherichia coli. The middle drying megmoondong(Liriope platyphylla Wang et Tang) and drying megmoondong extracts showed no antimicrobial effect against Escherichia coli.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2007.11a
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• pp.366.1-366.1
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• 2007

• Bulletin of Food Technology
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• v.19 no.2
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• pp.140-148
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• 2006

• Food Science and Preservation
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• v.16 no.6
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• pp.924-928
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• 2009

Green tea has been shown to have multifunctional health-promoting properties including cholesterol level control an antidiabetic effect and anticancer, antioxidant, and antimicrobial properties, inboth in vivo and in vitro experiments.We earlier reported antifungal and antibacterial effects of green tea extract by investigating cell membrane functions. The purpose of the present study was to purify and identify antimicrobial substances from green tea extract. Such materials were extracted from green tea (Camellia sinensis. var. sinensis) and purified by high-performance liquid chromatography. The antimicrobial substances in the extract were identified as epicatechin gallate and epigallocatechin gallate by nuclear magnetic resonance spectrophotometry.

• Toxicological Research
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• v.30 no.4
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• pp.283-289
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• 2014

Tea flavonoids and polyphenols are well known for their extraordinary antioxidant activity which is considered important for anti-aging processes in animals. This study evaluated the anti-wrinkle effects of three different kinds of tea (Camellia sinensis) water extracts (CSWEs) including green, white, and black teas using a photoaged hairless mouse model. Data showed that the CSWE-treatment greatly improved skin conditions of mice suffering from UVB-induced photoaging, based on the parameters including the skin erythema index, moisture capacity, and transepidermal water loss. In addition, the wrinkle measurement and image analysis of skin replicas indicated that CSWEs remarkably inhibited wrinkle formation. In histological examination, the CSWE-treated mice exhibited diminished epidermal thickness and increased collagen and elastic fiber content, key signatures for skin restoration. Furthermore, the reduced expression of MMP-3, a collagen-degradative enzyme, was observed in the skin of CSWE-treated animals. Interestingly, comparative data between green, white, and black tea indicated that the anti-wrinkle activity of white tea and black tea is equally greater than that of green tea. Taken together, these data clearly demonstrated that CSWEs could be used as an effective anti-wrinkle agent in photoaged animal skin, implying their extended uses in therapeutics.