Combined effects of complex mixtures of potentially anti-carcinogenic compounds on antioxidant enzymes and carcinogen metabolizing enzymes in the rat.

The anti-carcinogenic activity of dietary fruit and vegetables observed in several epidemiological and experimental animal studies is likely to be an effect of the combined exposure to a large number of substances acting together. This is plausible, as these compounds are present simultaneously in a diet containing vegetables and fruit. Further, some compounds have been experimentally demonstrated to modify several mechanisms involved in carcinogenesis. The effect of combined exposure is demonstrated in the present article, summarizing the effects of a complex mixture of anti-carcinogenic substances (from broccoli) on different antioxidative defense enzymes and on cytochrome P-450 activities in rat liver, kidney and colon. The responses were related to the levels of different specific glucosinolates.