Structure-function characterization of phenanthridinium compounds as mutagens in Salmonella.

The mutagenic activity of some phenanthridinium compounds was examined by using Salmonella typhimurium strain TA98. Microsomal enzyme activation of the compounds was necessary for the detection of frameshift mutagenesis. Amino and/or azido functions at both R3 and R8 were structural requisites for significant mutagenic activity, although mutagenicity was severely reduced for the diazido analog. When an azido or amino group was substituted by hydrogen at either R3 or R8, mutagenic activities were minimal, and the deaminated compound (3,8-dihydro derivative) was not mutagenic. Propidium was only slightly more mutagenic than the monoamino and monoazido analogs. Relationships between mutagenic activity and chemical structure of phenanthridinium compounds are discussed.