In vitro antimutagenicity of capsaicin toward heterocyclic amines in Salmonella typhimurium strain TA98.

Capsicum fruits are widely consumed as a component of the human diet. Capsaicin is the principle substance responsible for their hot, pungent taste. Heterocyclic amines (HCAs) are formed during cooking of meats and are mutagenic/carcinogenic compounds. In this study, we looked at whether capsaicin showed anti-mutagenic effects toward HCA-induced mutagenesis in Salmonella typhimurium TA98 when incubated with 0.5 mg liver S9 protein from rat, hamster and human. The HCAs used were Trp-P-2, Glu-P-1 and PhIP. Capsaicin, at non-toxic amounts of 0.25 and 0.5 micromole/plate, expressed a dose-dependent inhibition of the mutagenicity of Glu-P-1 and PhIP when they are metabolically activated by rat, hamster and human liver S9 and of Trp-P-2 when activated by rat and hamster liver S9. In contrast, capsaicin enhanced the mutagenicity of Trp-P-2 in TA98 when incubated with human liver S9. The lack of consistency in the anti-mutagenic action of capsaicin toward HCAs is puzzling and currently unresolved.