Differences in mutagenicity of the optical enantiomers of the diastereomeric benzo[a]pyrene 7,8-diol-9,10-epoxides

Abstract

Summary Substantial differences in the mutagenic activities of the optically pure (+)- and (−)-enantiomers of the diastereomeric 7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrenes were observed in strains TA98 and TA100 of Salmonella typhimurium and Chinese hamster V79 cells. In strains TA98 and TA100 (−)-7β,8α-dihydroxy-9β, 10β-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene was the most mutagenic compound, inducing from 1.3 to 9.5 times as many mutations as the three other optically active stereoisomers. In Chinese hamster cells (+)-7β,8α-dihydroxy-9α,10α-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene was the most mutagenic compound inducing from 6 to 18 times as many variant colonies as the three other isomers. These results with known metabolites of the environmental carcinogen benzo[a]pyrene represent the first report of differences in mutagenic activity among optical enantiomers.