Quantitative assessment of the genotoxicity of fecapentaenes

Fecapentaenes are a group of fecal mutagens of microbial origin isolated from human stools. Fecapentaene-12 (F-12) and fecapentaene-14 (F-14), differing only in two carbon atoms in the side chain, are glyceryl ethers with a highly reactive chromophoric aliphatic side chain incorporating a conjugated pentaene moiety. Although these compounds are known for their genotoxicity, no test systems have been developed to precisely assess their relative genotoxicity. In this study F-12 and F-14 were assayed for their genotoxicity using the SOS Chromotest in which the induction of beta-galactosidase in E. coli PQ37 was used as a quantitative measure of biological activity. The activity obtained with F-12 and F-14 was compared with that of 4-nitroquinoline oxide (4-NQO) as the reference standard of a direct acting mutagen. While F-14 was almost as active as 4-NQO, F-12 was only about 25% as active as F-14, the higher analog.