Effect of paraoxon-methyl and parathion-methyl on DNA in human lymphocytes and protective action of vitamin C

✍ Scribed by Blasiak, Janusz; Kowalik, Joanna

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 119 KB
• Volume: 55
• Category: Article
• ISSN: 1526-498X
• DOI: 10.1002/(sici)1096-9063(199912)55:12<1182::aid-ps75>3.0.co;2-#

✦ Synopsis

The molecular basis of the genotoxicity of the commonly used organophosphorus insecticide, parathion-methyl is poorly understood and there is a lack of information on the possible effects of its metabolic conversion products. In the present work the action of parathion-methyl and its immediate metabolite paraoxon-methyl on DNA in human lymphocytes was compared using the comet assay. Parathion-methyl at 25 and 75 mM did not cause any signi®cant changes but at 200 mM a signi®cant increase in the tail moment was observed as compared with the control. Paraoxon-methyl at 25, 75 and 200 mM evoked dose-dependent DNA damage measured as a signi®cant increase in comet tail moment of lymphocytes. The change evoked by paraoxon-methyl at 200 mM was much more pronounced than that by parathion-methyl at the same concentration. To search for the mechanism underlying the observed effect, the action of a well-known antioxidant, vitamin C, along with parathion-methyl and paraoxon-methyl was studied. The vitamin at 10 and 50 mM reduced the DNA-damaging activity of paraoxon-methyl at all its concentrations. The results indicate that the reported genotoxic effects of parathion-methyl could be mainly attributed to its metabolite paraoxon-methyl. The protective action of vitamin C suggests that paraoxon-methyl may cause oxidative DNA damage.