Modulatory effects of black tea polyphenols on rat forestomach carcinogenesis.
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.
Murugan
R Senthil
RS
Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar, 608 002, Tamil Nadu, India.
Mohan
K V P Chandra
KV
Nagini
S
S