Phototransformation of 2-aminofluorene into N-oxidized mutagens

Exposure to sunlight or artificial sources of near u.v. light transforms 2-aminofluorene into a direct-acting mutagenic agent in the Ames/Salmonella histidine reversion bioassay. H.p.l.c. fractionation indicates that the majority of this mutagenic activity elutes as a single A254 absorbance peak. I.r. spectroscopy of the fractionated active fraction shows the presence of significant quantities of 2-nitrofluorene. The use of a nitroreductase deficient strain of Salmonella, coupled with t.l.c. analysis, however, also indicates the presence of a minor component whose mutagenic and t.l.c. properties are identical with 2-nitrosofluorene. These results implicate a specific mechanism by which aromatic amines can be photo-oxidized to potentially harmful genotoxic agents.