Japanese green tea as a cancer preventive in humans
Japanese green tea as a cancer preventive in humans
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DOI：
10.1111/j.1753-4887.1996.tb03821.x
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发表时间：
1996-11-01
影响因子：
6.1
通讯作者：
Sakai, Y
中科院分区：
文献类型：
--
作者：
Fujiki, H;Suganuma, M;Sakai, Y
如今喝绿茶已成为日本文化的一部分。茶树Camellia sinensis是12世纪一位日本禅师从中国进口到日本作为药物的。然而，作为一种药物，茶的研究并不多。目前，我们在饭前和饭后喝茶，即全天喝茶。一杯绿茶汤含有约100-200毫克单宁，其主要成分是(-)-表没食子儿茶素没食子酸酯(EGCG)。因此，EGCG是茶多酚或茶单宁中的一种。 1983年，我们与当时冈山大学药理学教授奥田拓夫合作，首次对EGCG作为防癌物质进行了科学检验。我们首先研究了源自药用植物和药物的多酚的抗癌作用。 1, 2 我们首先检查了多酚是否与肿瘤促进剂 1 2-O-十四烷酰佛波醇-13-乙酸酯 (TPA) 共享佛波酯受体。 3 实验上，EGCG 以剂量依赖性方式抑制小鼠皮肤膜部分中佛波酯受体的特异性结合。 EGCG抑制作用的中位有效剂量(ED^低于50^)比TPA小约300倍。此外，从瘿中分离出的五-O-没食子酰基-βD-葡萄糖、五味子、花梗素、车布林酸和花蕾素 A 与 EGCG 结合到相同的受体，具有相似的 ED^ sub 50^ 值，尽管它们的结构既不与 TPA 相关，也不相互关联。 1 这些结果提出了一个问题：EGCG 是否充当拮抗剂，抑制 TPA 的作用，或者作为激动剂，像 TPA 一样激活蛋白激酶 C？
Drinking green tea today is part of Japanese culture. The tea plant Camellia sinensis was imported by a Japanese Zen priest in the 12th century from China to Japan as a medicine. However, as a medicine, tea was not much studied. At present we drink tea during and after meals, that is, throughout the day. One cup of green tea infusion contains about 100-200 mg of tannins, the main constituent of which is (-)-epigallocatechin gallate (EGCG). Thus, EGCG is one of the tea polyphenols or tea tannins.In 1983 we did the first scientific examination of EGCG as a cancer-preventive material in collaboration with Takuo Okuda, who was a professor of pharmacology at Okayama University at that time. We began with a study of the anticarcinogenic effects of polyphenols derived from medicinal plants and drugs. 1, 2 We first examined whether a polyphenol shared the phorbol ester receptor with a tumor promoter, 1 2-O-tetradecanoylphorbol-13-acetate (TPA). 3 Experimentally, EGCG inhibited in a dose-dependent manner the specific^ sup 3^ H-TPA binding to the phorbol ester receptor in a membrane fraction of mouse skin. The median effective dose (ED^ sub 50^) of EGCG for inhibition was about 300 times less than that of TPA. Moreover, penta-O-galloyl-betaD-glucose isolated from a gall, Shisandrea fructus, pedunculagin, chebulinic acid, and buddledin A bound to the same receptors with similar ED^ sub 50^ values as EGCG did, although their structures are related neither to that of TPA nor to each other. 1 These results raised a question: Does EGCG act as an antagonist, inhibiting the action of TPA, or as an agonist, activating protein kinase C as TPA does?