Effects of caffeine on ultraviolet-induced base-pair substitution and frameshift mutagenesis in Salmonella.

Using an excision-deficient, di-auxotrophic, strain of Salmonella typhimurium we have shown that caffeine significantly inhibits the formation of ultraviolet-induced base-pair substitution mutations, but has only a marginal effect on the formation of frameshift mutations in the same population of cells.