Genotoxicity evaluation of 4-carboxyl- 2,6-dinitrophenylazohydroxynaphthalenes in mice

A short-term in vivo genotoxicity evaluation of 4-carboxyl-2,6-dinitrophenylazohydronaphthalenes (AZ-01 to AZ-04) has been carried out in mice. Aqueous colloidal solutions of the dyes were administered to mice on each day for 5 successive days using gastric gavages. Two end point assessments of the genotoxicity potentials of the dyes were assessed using comet assay and chromosomal aberration studies using the mice bone marrow cells. The dyes were well tolerated at the doses investigated, as there were no deaths or any adverse pharmacotoxic events. Dose-dependent DNA damage (in terms of percentage of tail DNA and Olive tail moment) occurred with AZ-01 and AZ-02, although the effects were significant only with the highest doses. AZ-03 gave similar patterns with those of AZ-01 and AZ-02, while replacement with butanone in AZ-04 altered the observed pattern. Minimal chromosomal damages were obtained for the four dyes, with AZ-01 and AZ-02 giving nonsignificant damages, while the highest dose of AZ-03 produced significant aberrations in terms of breaks. Some minor isochromatid breaks and gaps were also noticed in the dye-treated mice. Mitotic indices in all cases were not significantly different from concomitantly administered vehicle control showing lack of cytotoxicity of the monoazo dyes at these doses. The monoazo dyes show the potential of being utilized as colorants, pending further required tests.