Bu-Abbas A, Clifford M N, Ioannides C, Walker R
School of Biological Sciences, University of Surrey, Guildford, UK.
Food Chem Toxicol. 1995 Jan;33(1):27-30. doi: 10.1016/0278-6915(95)80244-4.
Studies were conducted to investigate whether aqueous extracts of green tea, administered to rats at concentrations consumed by humans, could influence the phase II conjugation reactions in the liver, and so contribute to its established anticarcinogenic activity. Exposure of rats to green tea (2.5%, w/v), as the sole drinking fluid, for 4 wk did not influence sulfotransferase, epoxide hydrolase nor glutathione S-transferase activities. UDP glucuronosyl transferase activity, when determined using 2-aminophenol as the substrate, was increased by 100% following treatment with tea. Finally, green tea had no effect on the enzymes affording protection against reactive oxygen species, namely catalase, glutathione peroxidase and superoxide dismutase. It is postulated that the enhanced glucuronidation may contribute to the anticarcinogenic effect of green tea by facilitating the metabolism of chemical carcinogens into inactive, readily excretable products.
开展了多项研究，以调查按照人类饮用浓度给予大鼠绿茶水提取物是否会影响肝脏中的II相共轭反应，从而有助于其已确定的抗癌活性。将大鼠作为唯一的饮用水源暴露于绿茶（2.5%，w/v）中4周，并未影响磺基转移酶、环氧化物水解酶和谷胱甘肽S-转移酶的活性。当使用2-氨基酚作为底物测定时，经茶处理后UDP葡萄糖醛酸基转移酶活性增加了100%。最后，绿茶对提供针对活性氧的保护作用的酶，即过氧化氢酶、谷胱甘肽过氧化物酶和超氧化物歧化酶没有影响。据推测，增强的葡萄糖醛酸化作用可能通过促进化学致癌物代谢为无活性、易于排泄的产物，从而有助于绿茶的抗癌作用。
