Mutagenicity of Carcinogenic Mycotoxins in Salmonella typhimuriumi

Fifteen mycotoxins and two chemically modified toxins were tested for mutagenic ability in the His revenant assay with the use of Salmonella typhimurium TA 98 and TA 100. Bisfuranoid mycotoxins such as aflatoxin B,, aflatoxin G,, sterigmatocystin, and O-acetylsterigmatocystin were positive in the routine test method, and epoxide mycotoxins such as PR-toxin and crotocin were positive only when the test strains were preincubated with the mycotoxins in the presence of the fortified S-9 (supernatant fraction, 9000 x g for 20 min). Anthraquinoid hepatocarcinogens such as (-)-luteoskyrin and (+)-rugulosin; lactones such as citrinin, penicillic acid, and patulin; and chlorinated carcinogens such as chloropeptide and griseofulvin were negative in the routine and preincubation assay methods. Fusarium mycotoxins such as trichothecenes and zearalenone also failed to demon strate mutagenicity. However, among the trichothecene mycotoxins, crotocin, a bis-epoxide trichothecene, en hanced the mutagenicity of aflatoxin B,. In vitro supple ment of glutathione to the S-9 mixture enhanced the mutagenicity of aflatoxin B,, and prior administration of various hepatotoxic agents to rats reduced the S-9-dependent mutagenicity of aflatoxin B,. Organ and species variations of aflatoxin B, mutagenicity were examined and their microsomal oxygenase activities were dis cussed.