Yang C S, Lee M J, Chen L, Yang G Y
Laboratory for Cancer Research, Rutgers University, Piscataway, New Jersey 08855-0789, USA.
Environ Health Perspect. 1997 Jun;105 Suppl 4(Suppl 4):971-6. doi: 10.1289/ehp.97105s4971.
Many polyphenolic compounds have demonstrated anticarcinogenic activities in animal models. These compounds include flavanone, flavonols, isoflavone, and catechins. In this article, tea catechins will be used as an example to illustrate current research in this area. Many laboratory studies have demonstrated the inhibition of tumorigenesis in animal models by different tea preparations. The animal models include tumorigenesis in the mouse lung, rat and mouse esophagi, mouse forestomach, mouse skin, mouse duodenum, rat small intestine, rat and mouse livers, and rat colon. In most of the studies, the inhibitory activity of tea could be demonstrated when tea preparations were given either during or after the carcinogen treatment period. Black tea was also effective, although the activity was weaker than green tea in some experiments. Decaffeinated tea preparations were also active in many model systems. The molecular mechanisms for these broad inhibitory actions are not fully understood. They are most likely related to the biochemical actions of the tea polyphenols, which include antioxidative activities and inhibition of cell proliferation and of tumor promotion-related activities. The effect of tea consumption on human cancers is not clear in spite of numerous investigations. The bioavailability and pharmacokinetics of tea polyphenols are being studied in animals and humans to provide a basis for more quantitative analyses on the effect of tea on carcinogenesis. More mechanistic and dose-response studies will help us to understand the effects of tea consumption on human carcinogenesis.
许多多酚类化合物在动物模型中已显示出抗癌活性。这些化合物包括黄烷酮、黄酮醇、异黄酮和儿茶素。在本文中，将以茶儿茶素为例来说明该领域的当前研究。许多实验室研究已证明不同的茶制剂可抑制动物模型中的肿瘤发生。动物模型包括小鼠肺癌、大鼠和小鼠食管癌、小鼠前胃、小鼠皮肤、小鼠十二指肠、大鼠小肠、大鼠和小鼠肝脏以及大鼠结肠。在大多数研究中，无论是在致癌物处理期间还是之后给予茶制剂，都能证明茶的抑制活性。红茶也有效，尽管在某些实验中其活性比绿茶弱。脱咖啡因茶制剂在许多模型系统中也具有活性。这些广泛抑制作用的分子机制尚未完全了解。它们很可能与茶多酚的生化作用有关，包括抗氧化活性以及对细胞增殖和肿瘤促进相关活性的抑制。尽管进行了大量研究，但饮茶对人类癌症的影响尚不清楚。目前正在动物和人类中研究茶多酚的生物利用度和药代动力学，以便为更定量地分析茶对致癌作用的影响提供依据。更多的机制研究和剂量反应研究将有助于我们了解饮茶对人类致癌作用的影响。
