Isoflavones are biologically active
plant derived compounds that have several health promoting effects. In the present study hitherto unknown effects of one of the well known isoflavonoids,
daidzein, has been evaluated on its chemo-preventive action against breast
cancers in pre-pubertal rats. Either
daidzein (500 mug/g bwt) or vehicle,
dimethyl sulphoxide (
DMSO), was administered at 16th, 18th, and 20th day post-partum and the chemopreventive efficacy was evaluated in dimethylbenz[a]nthracene (DMBA) induced Sprague-Dawley rats, at 50th day. To elucidate the mechanism of action, the antioxidative status was also examined in the liver and mammary gland of prebubertal rats using two different doses of
daidzein (0.5 mg/kg bwt and 50 mg/kg bwt, p.o.) for 10 days. The specific activity of
antioxidant enzymes as well as
reduced glutathione (GSH) level and peroxidative damage were evaluated spectrophotometrically, both in liver as well as in mammary gland. Animals treated with
daidzein pre-pubertally, showed a significant reduction in the
tumorigenesis of mammary gland up to 37.4% as compared to animals induced for
tumors with DMBA. In animals treated with 50 mg/kg of
daidzein, a significant increase in the specific activities of the
antioxidant enzymes such as
superoxide dismutase (SOD),
catalase (CAT),
glutathione peroxidase (GPx),
glutathione transferase (GST),
DT-diaphorase (DTD), and in GSH content were observed in both liver and mammary gland. Expectedly, the specific activity of
lactate dehydrogenase (LDH) and level of peroxidative damage was decreased, as compared to that of control group of animals. Our results suggest that,
daidzein can be considered as a potent chemopreventive agent against mammary
carcinogenesis in pre-pubertal animals, with modulation of
antioxidant enzymes being one of its mechanisms of actions.