Evaluation of antimutagenic effect of todralazine in cultured lymphocytes

Todralazine, an antihypertensive drug from the hydrazinophthalazine group, significantly decreased the activities of benzo[a]pyrene and mitomycin C in three short-term genotoxicity tests in human lymphocyte cultures, The thio guanine resistance test, the cytokinesis-blocked micronucleus assay and the sister chromatid exchange test were used to demonstrate the antimutagenici ty of todralazine. Todralazine lowered the level of free radicals generated by human granulocytes in vitro in the presence of benzo[a] pyrene and also in the presence of the granulocyte activator and tumor promoter phorboI my ristate acetate. These results, together with our previous data obtained in the standard bacterial Ames test, strongly suggest that todrala-zinc is a good antimutagen in: vitro and deserves further research on its inhibitory action on mutagenesis and carcinogenesis.