The Role of Ethyl and Fluorine Substitution in the 4′-Position for N,N-Diethyl-4-aminoazobenzene Mutagenicity and Azo Reduction

: The mutagenicity and azo reduction rate of N,N-diethyl-4-aminoazobenzene (DEAB) were influenced by substitution in the 4′-position with a ethyl or a fluorine group. The parent dye (DEAB) was shown to be slightly mutagenic with Salmonella typhimurium TA98 using Aroclor 1254-pretreated 9000 x g supernatant fractions from rat liver. Introduction of a 4′-ethyl group in DEAB did not affect mutagenicity of the dye, but a 4-fluoro group markedly enchanced its mutagenicity. DEAB underwent azo reduction and its reduction rate was influenced by 4′-substituents. A 4′-fluoro group in DEAB increased its azo reduction rate, while a 4′-ethyl group abolished it. Inhibitors of cytochrome P-450 also inhibited 4′-fluoro-DEAB mutagenicity and azo reduction.