Komori A, Yatsunami J, Okabe S, Abe S, Hara K, Suganuma M, Kim S J, Fujiki H
Cancer Prevention Division, National Cancer Center Research Institute, Tokyo.
Jpn J Clin Oncol. 1993 Jun;23(3):186-90.
The main physiologically active polyphenol in green tea extract is (-)-epigallocatechin gallate (EGCG). Green tea extract has an advantage over EGCG as a cancer chemopreventive agent for humans, as is apparent from the Japanese custom of injesting green tea on a daily basis. Green tea extract similarly inhibited protein kinase C activation by teleocidin, a tumor promoter, as did EGCG. In addition, EGCG and green tea extract showed inhibitory effects on the growth of lung and mammary cancer cell lines with similar potencies. An experiment using the estrogen-dependent MCF-7 cell line showed the mechanisms of action of these compounds to be inhibiting the interaction of estrogen with its receptors. Considering our previous results of a single application of EGCG to mouse skin inhibiting the specific binding of 3H-12-0-tetradecanoylphorbol-13-acetate (3H-TPA) and 3H-okadaic acid, we postulated that EGCG and compounds in green tea extracts would block the interaction of tumor promoters, hormones and growth factors with their receptors: a kind of sealing effect. The sealing effect would account for reversible growth arrest, and may be induced by various kinds of compound.
绿茶提取物中主要的生理活性多酚是（-）-表没食子儿茶素没食子酸酯（EGCG）。从日本人日常饮用绿茶的习俗可以明显看出，绿茶提取物作为一种癌症化学预防剂，相较于EGCG对人类具有优势。绿茶提取物与EGCG一样，同样能抑制肿瘤促进剂teleocidin对蛋白激酶C的激活作用。此外，EGCG和绿茶提取物对肺癌和乳腺癌细胞系的生长具有相似效力的抑制作用。一项使用雌激素依赖性MCF-7细胞系的实验表明，这些化合物的作用机制是抑制雌激素与其受体的相互作用。考虑到我们之前将EGCG单次应用于小鼠皮肤可抑制3H-12-氧十四烷酰佛波醇-13-乙酸酯（3H-TPA）和3H-冈田酸特异性结合的结果，我们推测EGCG和绿茶提取物中的化合物会阻断肿瘤促进剂、激素和生长因子与其受体的相互作用：一种封闭效应。这种封闭效应可解释可逆性生长停滞，并且可能由多种化合物诱导产生。
