Inhibitory effects of dietary caraway essential oils on 1,2-dimethylhydrazine-induced colon carcinogenesis is mediated by liver xenobiotic metabolizing enzymes

The effects of dietary essential oils prepared from caraway seeds on colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) in rats has been studied. The number of aberrant crypt foci (ACF) and aberrant crypt (AC) induced by DMH were found to be significantly inhibited in colon of rats treated with essential oils in diet (0.01 and 0.1%). To find out the mechanism(s) by which the essential oils reduced colon premalignancies, plasma, liver, and colon tissues were collected and analyzed for parameters related to oxidative stress and xenobiotic metabolizing enzymes. Lack of influence of caraway extracts on hepatic lipid peroxidation products, superoxide dismutase (SOD), catalase (CAT) and ferric reducing ability of plasma (FRAP) may suggest that the oils do not interfere with these factors. However, it was clearly shown that DMH-related changes in hepatic and colonic cytochrome P4501A1 (CYP1A1) and glutathione S-transferae (GST) activities were recovered in liver but not in colon tissue in animals treated with caraway oil preparations. In conclusion, histopathological and biochemical data clearly showed that inhibition of colon premalignant lesions induced by DMH is mediated by interference of caraway oil components in the activities of the main hepatic xenobiotic metabolizing enzymes.