Effect of caffeine on base-pair substitution and frameshift mutagenesis induced in salmonella typhimurium

ABSTRACT

The mutagenicity of caffeine was studied by using 2 different Ames Salmonellamutagenicity tester strains. Three short-term assays [plate incorporation,preincubation and the Ames-fluctuation test] were carried out to evaluate thegenotoxicity of caffeine. The effect of some extracts of the culturalfiltrate of Alternaria eichhorniae on the original strains and theirrevertants was also examined. Mutagenicity data for caffeine demonstrated adose-response at levels that are not excessively toxic to bacteria. In allcases, the addition of preincubation resulted in greater sensitivity thanplate incorporation. Testing conducted with strains that carry the base- pairsubstitutions and frame-shift mutations in different repair backgroundsindicated that the presence of pKM101 and the deletion of the uvr B genefacilitate the detection of caffeine as mutagen. The mutagenic activity ofcaffeine determined by employing Salmonella typhimurium mutagenesis assay[TA1535 and TA97] revealed the mutagenic potency of base-pair substitutions andframe-shift mutations in all assays, without any need for metabolicactivation, indicating the presence of direct-action mutagen