Modulatory effects of black tea polyphenols on rat forestomach carcinogenesis.

Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar, 608 002, Tamil Nadu, India.
Toxicology mechanisms and methods (Impact Factor: 1.37). 01/2007; 17(8):467-74. DOI: 10.1080/15376510701190797
Source: PubMed

ABSTRACT ABSTRACT The present study was designed to evaluate the chemopreventive effects of black tea polyphenols (Polyphenon-B) on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced gastric carcinogenesis in Wistar rats. Intragastric administration of MNNG induced well-differentiated squamous cell carcinomas that showed diminished mitochondrial lipid and protein oxidation and an increase in antioxidants. In contrast to tumor tissue, the liver mitochondria of tumor-bearing animals showed elevated lipid and protein oxidation with compromised antioxidant defenses. Dietary administration of Polyphenon-B effectively suppressed MNNG-induced stomach tumors, modulated mitochondrial lipid and protein oxidation, and enhanced antioxidant enzyme activities in the stomach and liver. Our results suggest that Polyphenon-B may exert its chemopreventive effects by modulating mitochondrial cellular redox status in the tumor as well as in the host liver.

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