Invitro genotoxicity evaluation of 4-carboxyl-2,6-dinitrophenylazohydroxynaphthalenes using human lymphocytes.
The genotoxicity of a new monoazo dye series, 4-carboxyl-2,6-dinitrophenylazohydroxynaphthalenes was evaluated using human lymphocytes by alkaline comet assay. In this study freshly isolated human lymphocytes were exposed to the dyes (AZ-01, -02, -03 and -04) at concentrations ranging from 0 to 500 ?M for 3hours at 37 °C. Appropriate negative (culture medium) and positive (100 ?M methyl methane sulfonate) controls were set up alongside with the dye-treated cells. Extent of DNA damage was assessed by Comet assay. The results showed that 4 dyes were showed varying results with respect to the parameters of DNA damage studied. AZ-01 showed concentration dependent DNA damage (% Tail DNA) whereas lower concentrations (31.25-62.5 ?M) were not producing any significant difference in the tail extent moment. On the other hand AZ-02, the positional isomer of AZ-01, showed non-genotoxic effects at lower concentrations for the 2 DNA parameters. Also AZ-03 and AZ-04 (possessing additional C-7 substituents) were not produced any significant genotoxic effect at all concentrations relative to the negative control. Two of these monoazo dyes showed the potential of being used as edible colorants. The results concluded that genotoxicity of congeneric dyes bear a direct relationship to their chemical structure.