Na Hye-Kyung, Surh Young-Joon
National Research Laboratory of Molecular Carcinogenesis and Chemoprevention, College of Pharmacy, Seoul National University, Shinlim-dong, Kwanak-ku, Seoul 151-742, South Korea.
Food Chem Toxicol. 2008 Apr;46(4):1271-8. doi: 10.1016/j.fct.2007.10.006. Epub 2007 Oct 17.
Frequent consumption of green tea, one of the most popular and widely consumed beverages, has been known to protect against development of various cancers according to numerous experimental and several population-based studies. Molecular mechanisms underlying chemopreventive effects exerted by green tea and its components have been extensively investigated. (-)-Epigallocatechin-3-gallate (EGCG), a major green tea polyphenol, has been shown to induce expression of glutathione S-transferase, glutathione peroxidase, glutamate cysteine ligase, hemeoxygenase-1, etc. that are involved in the elimination or inactivation of reactive oxygen species and electrophiles implicated in multi-stage carcinogenesis. The redox-sensitive transcription factor, nuclear factor erythroid 2 p45 (NF-E2)-related factor (Nrf2) plays a key role in regulating induction of phase II detoxifying or antioxidant enzymes. Thus, activation of Nrf2 is considered to be an important molecular target of many chemopreventive and chemoprotective agents. This review summarizes the molecular basis of chemoprevention and cytoprotection afforded by EGCG with emphasis on its ability to modulate Nrf2-mediated cellular events.
经常饮用绿茶,这种最受欢迎且饮用广泛的饮品之一,根据众多实验研究和一些基于人群的研究,已知其能够预防多种癌症的发生。绿茶及其成分发挥化学预防作用的分子机制已得到广泛研究。(-)-表没食子儿茶素-3-没食子酸酯(EGCG),一种主要的绿茶多酚,已被证明可诱导谷胱甘肽S-转移酶、谷胱甘肽过氧化物酶、谷氨酸半胱氨酸连接酶、血红素加氧酶-1等的表达,这些酶参与消除或失活与多阶段致癌作用相关的活性氧和亲电试剂。氧化还原敏感转录因子,核因子红系2 p45(NF-E2)相关因子(Nrf2)在调节II期解毒或抗氧化酶的诱导中起关键作用。因此,Nrf2的激活被认为是许多化学预防和化学保护剂的重要分子靶点。本综述总结了EGCG提供化学预防和细胞保护的分子基础,重点在于其调节Nrf2介导的细胞事件的能力。