Mechanism of caffeine repression of mitomycin C induced reversion in Salmonella typhimurium strain TA94.

Caffeine significantly repressed his- reversion of Salmonella typhimurium TA94 induced by mitomycin C (MMC). The decrease in the number of revertants with increasing concentrations of caffeine was accompanied by a decrease in cell viability. Reversion rates (revertants/viable cells) in the presence of caffeine were higher than in the absence of caffeine. The results of this study indicate that the apparent antimutagenic activity of caffeine on MMC induced reversion is due to the potentiation by caffeine of MMC-induced lethality.