Studies on antimutagenic effects of guava (Psidium guajava) in Salmonella typhimurium.

The water and chloroform extracts of guava were tested for their antimutagenicity. The water extract was effective in inactivating the mutagenicity of direct-acting mutagens, e.g., 4-nitro-o-phenylenediamine, sodium azide, and the S9-dependent mutagen, 2-aminofluorene, in the tester strains of Salmonella typhimurium. The chloroform extract was inactive. Autoclaving of the water extract for 15 min did not reduced its activity appreciably. The enhanced inhibitory activity of the extracts on pre-incubation suggests the possibility of desmutagens in the extracts. Besides ascorbic acid and citric acid, the major constituents of the extracts, the role of other antimutagenic factors in the extracts cannot be ruled out.