Nitroreduction of benznidazole and nifurtimox by rat and human feces

Rat and human feces are able to reduce nitro group from Benznidazole (N-benzyl-2-nitro-1-imidazole acetamide) and Nifurtimox (4[5-nitrofurfurylidene)-amino)-3-methylthiomorpholine-1,1-dioxide), two chemotherapeutic agents against Chagas' disease. Feces from rats treated with neomycin sulfate lack nitroreductase activity evidencing the bacterial origin of the enzyme.