Enhancing and inhibiting effects of propyl gallate on carcinogen-induced mutagenesis

The food additive propyl gallate has a significant effect on the mutagenic activities of several carcinogens as measured by the Salmonella/microsome mutagenesis assay. Propyl gallate (10(-2) to 10(-4) M) inhibits the mutagenic activites of the carcinogens N-methyl-N-'nitro-N-nitrosoguanidine (MNNG) and N-acetoxy-2-acetylaminofluorene (N-acetoxy-AAF). It also reduces the mutagenic effect of aflatoxin B1, a carcinogen which requires activation with a S-9 microsomal preparation. In contrast, propyl gallate at equimolar concentrations causes an enhancement of the mutagenic activities of the carcinogens N-hydroxy-2-acetylaminofluorene (N-hydroxy-AAF) and 4-nitroquinoline 1-oxide (4NQO). The enhancement of 4NQO-induced mutagenesis occurs with a range of 4NQO concentrations. Moreover, both frameshift (TA98) and base substitution (TA100) bacteria indicator strains demonstrate an enhanced mutagenesis to 4NQO in the presence of the propyl-gallate. Propylgallate alone has no effect on the spontaneous reversion rate of S. typhimurium to histidine propotrophy.