Structure-activity relationships of nitro and methyl-nitro derivatives of indoline, indole, indazole and benzimidazole in Salmonella typhimurium

Abstract

The mutagenic activities of eleven nitro derivatives and eleven N-methyl-nitro derivatives of indoline, indole, indazole and benzimidazole were investigated in Salmonella TA98 and TA100. The presence of a nitro group at C 4 or C 7 resulted in only weakly or nonmutagenic compounds, while a nitro group at C 2, C 5 or C 6 usually resulted in measurable mutagenic activity in the non- N-methylated compounds. Methylation of a ring nitrogen usually reduced the mutagenic activity of these nitroheterocyclics except 2-nitro-benzimidazole, which resulted in a better than 300-fold increase in mutagenic activity. A proposed mechanism for the increased mutagenic activity obtained by methylation of imidazole nitrogens may provide insights into the reasons for the potent mutagenicities observed for several similarly methylated cooked-food mutagens.