Carcinogen-metabolizing Enzyme Activity in the Liver: Beneficial Effect of the Phytotherapeutic Compound Yhk

In this study we investigated the effect of YHK supplementation on the activities of antioxidant, phase I and phase II metabolizing enzymes involved in detoxification as well on liver antioxidant defense system in rats. YHK was administered for four weeks to Wister rats. At the end of the treatment period, different cytochrome P450 (CYP) isoform and phase II enzyme activities were determined by incubation of the liver microsomes or cytosols with appropriate substrates Dietary supplementation of YHK (2%, w/v) to male rats for four weeks significantly increased the activities of glutathione peroxidase and catalase to 118% and 87% in liver as compared with corresponding normal diet fed control (P<0.05-0.001). CYP 1A2 activity was markedly increased in all the YHK treatment groups (P!0.05). CYP 1A1 activity was increased significantly in all the groups.Parallel to these changes, YHK feeding to mice also resulted in a considerable enhancement in the activity of phase I and II metabolizing enzymes such as glutathione S-transferase to 1.6 fold and 1.8 fold in liver as compared with corresponding normal diet fed control (P<0.05-0.01). The induction of such detoxifying enzymes by YHK suggest the potential value of this compound as protective agent against chemical carcinogensis and other forms of electrophilic toxicity. The significance of these results can be implicated in relation to cancer chemopreventive effects of YHK against the induction of tumors in various target organs.