Structural basis of the mutagenicity of phenylazoaniline dyes

The CASE (Computer-Automated Structure Evaluation) methodology was used to gain an understanding of the basis of mutagenicity of phenylazoanilines. It was found that the activity of these molecules is dependent upon an intact moiety that spans the azo linkage, i.e., the azo bond must remain intact for mutagenicity. The study also addressed the effect of sulfonation on the activity of these azo dyes. It was revealed that sulfonation at only certain sites resulted in loss of mutagenicity. Sulfonation of the structural moiety responsible for the activity of phenylazoaniline dyes did not necessarily result in complete elimination of activity as this substitution could generate new structural moieties which contribute to the activity of the molecules.