Dietary
antioxidants protect laboratory animals against the induction of tumours by a variety of chemical
carcinogens. Among possible mechanism of protection against chemical
carcinogenesis could be mediated via-
antioxidant-dependent induction of detoxifying
enzymes.
Curcumin, a yellow pigment from Curcuma longa, is a major component of turmeric and is commonly used as a spice and food colouring material and exhibits antiinflammatory antitumour, and
antioxidant properties. In this study we therefore investigated the effect of dietary supplementation of
curcumin on the activities of
antioxidant and phase II-metabolizing
enzymes involved in detoxification, and production of
reactive oxygen species were quantified in ddY male mice. Dietary supplementation of
curcumin (2%, w/v) to male ddY mice for 30 days significantly increased the activities of
glutathione peroxidase,
glutathione reductase,
glucose-6-phosphate dehydrogenase and
catalase to 189%, 179%, 189%, and 181% in liver and 143%, 134%, 167% and 115% in kidney respectively as compared with corresponding normal diet fed control (P<0.05-0.001). Parallel to these changes,
curcumin feeding to mice also resulted in a considerable enhancement in the activity of phase II-metabolizing
enzymes viz.
glutathione S-transferase and
quinone reductase to 1.7 and 1.8 times in liver and 1.1 and 1.3 times in kidney respectively as compared with corresponding normal diet fed control (P<0.05-0.01). In general, the increase in activities of
antioxidant and phase II-metabolizing
enzymes was more pronounced in liver as compared to kidney. The induction of such detoxifying
enzymes by
curcumin suggest the potential value of this compound as
protective agent against chemical
carcinogenesis and other forms of electrophilic toxicity. The significance of these results can be implicated in relation to
cancer chemopreventive effects of
curcumin against the induction of tumours in various target organs.