Cyclopiazonic acid inhibits mutagenic action of aflatoxin B(1)

Cyclopiazonic acid and aflatoxin B₁ are mycotoxins which can both be produced by the same moulds. Men can be exposed to these mycotoxins directly via ingestion of plant-derived food, as well as, indirectly via consumption of animal products. Although it is well known that aflatoxin B₁ is mutagenic, contradictory results exist on the mutagenicity of cyclopiazonic acid. Using the Ames test cyclopiazonic acid was not found to be mutagenic either with or without metabolic activation by S9-mix of Arochlor treated rats. However, the mutagenicity of aflatoxin B₁ was inhibited in the presence of cyclopiazonic acid. Since cyclopiazonic acid inhibited the formation of certain metabolites of caffeine and testosterone, it was concluded that the reduction of the mutagenicity of aflatoxin B₁ in the presence of cyclopiazonic acid results from the inhibition of the bioactivation of aflatoxin B₁ by certain cytochrome P450 enzymes.