Screening of antioxidants and other compounds for antimutagenic properties towards benzo[a]pyrene-induced mutagenicity in strain TA98 of Salmonella typhimurium.

Antioxidants and several other compounds, some of which are known to inhibit carcinogenicity, have been screened for their effectiveness as inhibitors of benzo[a]pyrene (BP) mutagenicity towards Salmonella typhimurium strain TA98 in the Ames test. A total of 32 compounds were tested. In the assay, metabolic activation of BP (8.2 nmoles/plate) was mediated by the S9 fraction from beta-naphthoflavone-induced rat livers. Among compounds which are known to inhibit carcinogenicity, retinol, phenothiazine, disulfiram, phenethylisothiocyanate and phenylisothiocyanate were the most effective inhibitors of BP mutagenicity, being effective at equimolar concentrations. Several other compounds showed inhibition at higher concentrations of antioxidant and the remainder showed little or no inhibition. Dose-response curves have been obtained for the 17 most active compounds. No general pattern of inhibition is obvious from our studies, inhibitors are not drawn ;from any single class of compounds, nor does a particular compound necessarily appear to inhibit more than one mutagen.