Mutagenicity testing of 5-(4-nitrophenyl)-2,4-pentadien-1-al (spy dust) and its metabolites in vitro and in vivo.

5-(4-Nitrophenyl)-2,4-pentadien-1-al (NPPD; spy dust) was tested for mutagenicity in Salmonella and for its ability to induce chromosome aberrations and sister chromatid exchanges (SCE) in cultured Chinese hamster ovary (CHO) cells and mouse bone marrow. Two metabolites of NPPD produced by the rat, 4-nitrobenzoic acid (NBA) and 4-nitrohippuric acid (NHA), were also tested in Salmonella and CHO cells. NPPD was mutagenic in Salmonella, and induced low-level increases in chromosome aberrations and SCE in bone marrow. It did not induce aberrations in CHO cells. NBA was positive in Salmonella and CHO cells, while NHA was negative. The mutagenicity of NPPD in Salmonella was partially, but not completely, eliminated in a strain lacking one of the bacterial nitroreductases.