Mutagenicity of bisbenzimidazole derivatives.

The mutagenicities of 2,2'-(di-3-hydroxyphenyl)-1H,1H'-[5,5']-bisbenzimidazole, 2,2'-(di-4-hydroxyphenyl)-1H,1H'-[5,5']-bisbenzimidazole, 2,2'-(di-3-methoxyphenyl)-1H,1H'-[5,5']-bisbenzimidazole, 2,2'-bis-(4-nitrophenyl)-1H,1H'-[5,5']-bisbenzimidazole, 2,2'-bis-(3-nitrophenyl)-1H,1H'-[5,5']-bisbenzimidazole, 2,2'-bis-(4-methylphenyl)-1H,1H'-[5,5']-bisbenzimidazole, 2,2'-(di-4-methoxyphenyl)-1H,1H'-[5,5']-bisbenzimidazole, and 2,2'-bis-(3-methylphenyl)-1H,1H'-[5,5']-bisbenzimidazole were studied in vitro using two strains of Salmonella typhimurium with frameshift mutation (TA98) and base-pair substitution mutation (TA100) as the plate incorporation assay in the absence of metabolic activation. These compounds are currently used to treat cancer. 4-Nitrophenyl and 3-nitrophenyl compounds were found to be mutagenic on both strains of Salmonella. A clear mutagenic response was seen in nitro-bound derivatives. The mutagenic response in Salmonella test strains (TA98, TA100) and structures of molecules suggest that nitro-bound molecules could be mutagenic.