Mutagenicity of 3 structurally related epoxides, with defined stereochemical configuration, in Saccharomyces cerevisiae and in V79 Chinese hamster cells.

3 structurally related epoxides, 3,4-epoxycyclohexene, trans-1,2,3,4-diepoxycyclohexane and trans-3,4-epoxycyclohexane-r-1,trans-2-diol (anti isomer) were tested for their ability to induce both point mutation, mitotic gene conversion and recombination in a diploid strain (D7) of the yeast Saccharomyces cerevisiae, with and without a mammalian microsomal activation system, and the formation of 6-thioguanine-resistant mutants in V79 hamster cells. Genetic effects were related to the alkylating properties of the epoxides, as measured by alkylation of 4-(p-nitrobenzyl)pyridine (NBP). Of the 3 epoxides, only 3,4-epoxycyclohexene, characterized by the highest reactivity towards NBP, induced all genetic effects in both test systems. A marginal activity was shown by trans-1,2,3,4-diepoxycyclohexane only in the yeast. The lack of genetic activity of the anti isomer of 3,4-epoxycyclohexane-1,2-diol, in spite of the formal similarity of its functional groups with those present in mutagenic polycyclic arene epoxydiols, was attributed to the dramatic reduction of lipophilicity of the molecule.