Effects of vitamins A, C, and E on aflatoxin B1-induced mutagenesis in Salmonella typhimurium TA-98 and TA-100

The effects of retinoids (vitamin A analogs) and vitamins C and E on the aflatoxin B1 (AFB1)-induced mutagenesis in Salmonella typhimurium TA-98 and TA-100 were investigated. The bioassay was performed under conditions that permitted the effects of vitamins on carcinogen metabolism to be assessed separately from effects on the expression of the mutated bacterial cell. Both retinoic acid and retinol inhibited (up to 50%) AFB1-induced mutagenesis in S. typhimurium TA-98, but only retinol inhibited (up to 75%) mutagenesis in TA-100. Retinoic acid inhibition of mutagenesis in S. typhimurium TA-98 was pronounced over a wide concentration range (i.e., 2 X 10(-10) to 2 X 10(-8) M) however, at the higher concentrations (i.e., 2 X 10(-8) to 2 X 10(-6) M range) the predominant effect was the inhibition of the metabolism of AFB1 to its mutagenic metabolites. Vitamin E was more potent in inhibiting the expression of AFB1-induced mutagenesis than vitamin C. However, the major inhibitory effects of vitamin E were related to the metabolism of AFB1, whereas vitamin C was inhibitory at both metabolic and the post-metabolic levels of the AFB1 mutagenesis assay. The results of these investigations suggest that vitamins A, C, or E inhibit both AFB1 metabolism to its mutagenic metabolites as well as the expression of AFB1-induced mutated bacterial cells.