INHIBITION OF POTASSIUM DICHROMATE MUTAGENICITY BY TODRALAZINE

Todralazine, an antihypertensive drug of the hydrazinophthalazine grou p, markedly decreased the mutagenic activity of potassium dichromate i n standard bacterial tests. at the highest todralazine dose tested inh ibition of potassium dichromate mutagenic activity by similar to 90% i n the Ames test and up to 100% (complete) inhibition in the Bacillus s ubtilis rec(-) assay was observed. Spectrophotometric analyses proved that todralazine induced reduction of Cr(VI) to Cr(III) and complexati on of Cr(III) ions. These spectrophotometric results may be a presumpt ive explanation of the observed mutagenic activity decrease, as it is known that Cr(III) is poorly transported across cell membranes and the refore is not mutagenic to bacterial cells. We perceive our experiment s as an example of attempts which should lead to an effective reductio n in chromium genotoxic and carcinogenic activity in exposed individua ls.