Can drinking tea prevent cancer?
Can drinking tea prevent cancer?
复制标题
喝茶能防癌吗？
作者：
J. Hengstler;R. Marchan;H. Bolt
茶仍然是全世界消费最多的饮料之一，有趣的是，一些流行病学研究表明，饮用茶，特别是绿茶，可以预防癌症。这引发了关于茶的潜在抗癌作用及其可能机制的争议（Jankun 等人，1997 年；Yang，1997 年）。在一份被广泛引用的信件中，Jankun 等人。鉴定出茶多酚表没食子儿茶素-3没食子酸酯(EGCG)作为尿激酶(uPA)的抑制剂(Jankun等人，1997)。 EGCG 被证明可以阻断 uPA 催化三联体的 His 57 和 Ser 195，从而干扰 uPA 识别其底物的能力（Jankun 等，1997）。然而，茶多酚通过抑制尿激酶来预防癌症的理论几乎立即受到了挑战（Yang 1997）。 Chung S. Yang 的一个论点是，Jankun 等人提出，茶多酚的有效浓度需要抑制尿激酶 (2-10 mM)。比组织中正常预期的 EGCG 浓度至少高出三到四个数量级（Yang 1997）。在讨论尿激酶抑制作为茶多酚的抗癌作用的作用十多年后，这一研究领域增加了很多知识。如今，预防氧化应激（Beyersmann 和 Hartwig 2008；Glahn 等人 2008；Arivarasu 等人 2008；Mates 等人 2008；Hengstler 和 Bolt 2008a, b；Sivalingam 等人 2008；Do Amaral 等人 2008；Abraham 和 Sugumar 2008）、调节致癌物代谢（Strassburg 等人，2008 年；Pelkonen 等人，2008 年；Naraharisetti 等人，2008 年；Hohme 等人，2007 年；Hewitt 等人，2007 年；Hengstler 等人，2000 年）和预防 DNA 损伤（Florl 和 Schulz，2008 年；Zhang 等人，2008 年；Hengstler 和 Bolt） 2008a, b)，我们期刊中最常讨论的机制，也被认为有助于茶多酚的抗癌作用。编辑们很高兴茶多酚领域最知名的专家 Chung S. Yang（新泽西大学）、Joshua D. Lamberg（宾夕法尼亚州立大学）和 Shenmin Sang（北卡罗来纳中央大学）接受了我们的邀请，并就茶的抗癌活性发表了全面的评论（Yang 等人，2008 年）。
Tea remains one of the most consumed beverages worldwide and interestingly, several epidemiological studies suggest that the consumption of tea, in particular green tea, may prevent cancer. This has initiated a controversial debate about the potential anti-carcinogenic eVects of tea and the possible mechanisms involved (Jankun et al. 1997; Yang 1997). In a widely cited correspondence, Jankun et al. identiWed the tea polyphenol epigallocateclin-3 gallate (EGCG), as an inhibitor of urokinase (uPA) (Jankun et al. 1997). EGCG was shown to block His 57 and Ser 195 of the uPA catalytic triad, thereby interfering with the ability of uPA to recognize its substrates (Jankun et al. 1997). However, the theory that tea polyphenols prevent cancer by inhibition of urokinase was almost immediately challenged (Yang 1997). One argument by Chung S. Yang was that the eVective concentration of tea polyphenols needed to inhibit urokinase (2–10 mM), suggested by Jankun et al. was at least three or four orders of magnitude higher than concentrations of EGCG normally expected in tissues (Yang 1997). More than 10 years after the discussion of a role of urokinase inhibition as an anti-carcinogenic eVect of tea polyphenols, much knowledge has been added to this Weld of research. Today, prevention of oxidative stress (Beyersmann and Hartwig 2008; Glahn et al. 2008; Arivarasu et al. 2008; Mates et al. 2008; Hengstler and Bolt 2008a, b; Sivalingam et al. 2008; Do Amaral et al. 2008; Abraham and Sugumar 2008), modulation of carcinogen metabolism (Strassburg et al. 2008; Pelkonen et al. 2008; Naraharisetti et al. 2008; Hohme et al. 2007; Hewitt et al. 2007; Hengstler et al. 2000) and prevention of DNA damage (Florl and Schulz 2008; Zhang et al. 2008; Hengstler and Bolt 2008a, b), mechanisms most frequently addressed in our journal, have also been suggested to contribute to the anti-carcinogenic eVects of tea polyphenols. The editors are pleased that Chung S. Yang (University of New Jersey), Joshua D. Lamberg (The Pennsylvania State University) and Shengmin Sang (North Carolina Central University), some of the most recognized experts in the Weld of tea polyphenols, have accepted our invitation and contributed a comprehensive review about the anti-carcinogenic activities of tea (Yang et al. 2008).