Inhibition of the mutagenicity of benzo[a]pyrene in the V79/HGPRT system by bioantioxidants.

In the presence of metabolic activation (S9 microsomal fraction of mouse-liver homogenate) the mutagenicity of benzo[a]pyrene (BP) in Chinese hamster V79 cells was inhibited by the phenolic bioantioxidants (BA) Dibunol (2,6-di-tert-butyl-4-methylphenol-D) and 5-methylresorcine(5-MR). The mixture BP + D and BP + 5-MR at molar ratios of 1:1 and 1:85 respectively showed no mutagenic activity compared to the control. One can assume that D and 5-MR inhibited BP-induced mutagenesis by binding the free radicals of BP metabolites with the formation of less active phenolic derivatives and also by linkage with cytochrome P-450, which prevents further metabolic activation of BP.