Inhibitory effect of tea polyphenols on hepatic preneoplastic foci in Wistar rats

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• 作者：Smita Srivastava ; Madhulika Singh ; Preeti Roy ; Sahdeo Prasad ; Jasmine George and Yogeshwer Shukla
• 关键词：Altered hepatic foci ; Green tea polyphenols ; Black tea polyphenols ; Medium term bioassay
• 刊名：Investigational New Drugs
• 出版年：2009
• 出版时间：December, 2009
• 年：2009
• 卷：27
• 期：6
• 页码：526-533
• 全文大小：310.8 KB

文摘

Tea (Camellia sinensis) is one of the most widely used beverages worldwide and tea consumption has been shown to have an inverse correlation to the incidence of human cancers in epidemiological and experimental studies. In the present study, the protective effects of green tea polyphenols (GTP) and black tea polyphenols (BTP) in Wistar rats were assessed by medium-term bioassay, using altered hepatic foci (AHF) as end point. Animals were exposed to a single dose of diethylnitrosamine (DEN; 200 mg/kg body weight intraperitoneally), and GTP (1 % ) and BTP (1 % ) were then administered orally together with 0.05 % 2-acetyl aminofluorene (2-AAF) crushed and mixed in the diet for 8 weeks. Numbers of AHF were scored and analyzed by quantitative stereology using the Image analysis system from frozen liver tissue sections. Tea polyphenol supplementation resulted in a significant protection against AHF induction in Wistar rats. In addition, levels of the positive biomarkers: γ-glutamyl transpeptidase and glutathione-S-transferase (placental form) were reduced with GTP and BTP supplementation. Levels of the negative biomarkers adenosine triphosphatase and glucose-6-phosphatase were also restored by GTP and BTP administration. Thus, these results show the hepatoprotective effects of GTP and BTP against DEN- and 2-AAF-induced AHF development.