Studies on the Structure Elucidation of Mutagenic Metabolites of 2,4-Dinitrobiphenyl Derivatives Against Salmonella typhimurium TA98.

Abstract

In order to elucidate the mechanisms of mutagenic activation of nitrobiphenyls in Salmonella typhimurium TA98 by use of a mammalian activation system, 2, 4, 6-trinitrobiphenyl (TNBp, 0.09 rev./nmol+S9) and 2, 4, 2', 4'-tetranitrobiphenyl (TNBp*, 457.19 rev./nmol+S9) were incubated with 10% S9 mix, separately, and their mutagenic metabolites were separated by SiO2 and Al2O3 column chromatography. In 2, 4, 6-TNBp, 4-amino-2, 6-dinitroBp (0.11 rev./nmol-S9) and 2, 4-diamino-6-nitroBp (0.50 rev./nmol-S9) were isolated from the reaction mixture of TNBp with S9 mix at 37°C for 48 h, and their structures determined by their mass and 1H-NMR spectra and the GC/MS data of their deamination products. In 2, 4, 2', 4'-TNBp*, 2, 4'-diamino-2', 4-dinitroBp (25460.01 rev./nmol-S9) and 2, 2'-dinitrobenzidine (33.79 rev./nmol-S9) were isolated from the reaction mixture, and their structures also determined by their physico-chemical and the GC/MS data of their deamination products. From the high-performance liquid chromatographic analysis of these metabolites, the mutagenicity of 2, 4'-diamino-2', 4-dinitroBp (-S9) contributed 100% of the mutagenicity of 2, 4, 2', 4'-TNBp* (+S9), whereas the mutagenicity of 4-amino-2, 6-dinitroBp and 2, 4-diamino-6-nitroBp contributed only 0.8 and 0.4% of that of 2, 4, 6-TNBp (+S9), respectively. Mutagenicity of 2, 2'-dinitrobenzidine was reduced to a half by the treatment with S9 mix, whereas the mutagenicity was expected to be enhanced by a mammalian metabolic activation system.