红茶多酚，即茶黄素，通过抑制氧化应激和抑制细胞培养中的细胞色素P450 1A1来防止细胞DNA损伤。

Black tea polyphenols, theaflavins, prevent cellular DNA damage by inhibiting oxidative stress and suppressing cytochrome P450 1A1 in cell cultures.

作者信息

Feng Qing, Torii Yasuyoshi, Uchida Koji, Nakamura Yoshimasa, Hara Yokihiko, Osawa Toshihiko

机构信息

Laboratory of Food and Biodynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464 8601, Japan.

出版信息

J Agric Food Chem. 2002 Jan 2;50(1):213-20. doi: 10.1021/jf010875c.

DOI:10.1021/jf010875c

PMID:11754570

Abstract

Tea polyphenols have been demonstrated as chemopreventive agents in a number of experimental models. However, less is known about the mechanism of chemoprevention by black tea compared with that of green tea. Some beneficial properties of theaflavins, the black tea polyphenols, were investigated in the present study. Theaflavins showed inhibitory effects on H(2)O(2)- and tert-butyl hydroperoxide (tBuOOH)-induced cytotoxicity (evaluated by tetrazolium bromide reduction), cellular oxidative stress (detected by oxidation of 2', 7'-dichlorofluorescin), and DNA damage (measured by amount of 8-OHdG and comet assay) in rat normal liver epithelium cell RL-34 cell lines. In addition, theaflavins also exhibited suppression of cytochrome P450 1A1 induced by omeprazole in the human hepatoma HepG2 cell line. Furthermore, when HepG2 cells were pretreated with omeprazole to induce CYP1A1, then exposed to benzo[a]pyrene (B[a]P), DNA damage was observed using the comet assay. However, theaflavins could inhibit this DNA damage. These results indicated that theaflavins could prevent cellular DNA damage by inhibiting oxidative stress and suppressing cytochrome P450 1A1 in cell cultures.

摘要

在许多实验模型中，茶多酚已被证明是化学预防剂。然而，与绿茶相比，红茶的化学预防机制尚鲜为人知。本研究对红茶多酚茶黄素的一些有益特性进行了研究。茶黄素对大鼠正常肝上皮细胞RL - 34细胞系中由过氧化氢（H₂O₂）和叔丁基过氧化氢（tBuOOH）诱导的细胞毒性（通过溴化四氮唑还原法评估）、细胞氧化应激（通过2',7'-二氯荧光素氧化检测）和DNA损伤（通过8-羟基脱氧鸟苷的量和彗星试验测量）均显示出抑制作用。此外，茶黄素在人肝癌HepG2细胞系中还表现出对奥美拉唑诱导的细胞色素P450 1A1的抑制作用。此外，当用奥美拉唑预处理HepG2细胞以诱导CYP1A1，然后使其暴露于苯并[a]芘（B[a]P）时，使用彗星试验观察到DNA损伤。然而，茶黄素可以抑制这种DNA损伤。这些结果表明，茶黄素在细胞培养中可通过抑制氧化应激和抑制细胞色素P450 1A1来预防细胞DNA损伤。