Quindoxin is a potent antibacterial agent that has been rigorously evaluated for genetic toxicity using the Salmonella microsomal assay system, where experimental testing demonstrated that this compound induces both base pair substitution mutations and frameshift mutations in Salmonella strains independently of the presence of a rat liver microsomal fraction, with mutagenic activity shown to be mechanistically dependent on the presence of its N-oxide functional group, as fully reduced quinoxaline lacked mutagenicity while partially reduced quinoxaline-N-oxide displayed diminished activity, and recA- and uvrB-deficient Salmonella strains exhibited increased susceptibility compared with wild-type strains.