IN VITRO EFFECTS OF SOME PESTICIDES ON GLUTATHIONE-S TRANSFERASE ACTIVITY

Human populations have been constantly exposed to pesticides due to their extensive use and presence in food and drinking water. Therefore, the aim of this study is to compare the inhibitory effect of three commonly used pesticides such as glyphosate (herbicide) and lambda-cyhalothrin and deltamethrin (insecticides) on glutathione S-transferase (GST) activity in vitro in human blood. GST enzyme activity was spectrophotometrically determined with observation of the formation of 1-chloro-2,4-dinitrobenzene-glutathione (CDNB-GSH) conjugate. GST activities were suppressed by all the pesticides tested; the deltamethrin was the most potent inhibitor, reducing GST activity in vitro in a dosage-dependent manner. The inhibition mechanism of pesticides on GST was different from each other. The inhibition types of glyphosate, lambda-cyhalothrin and deltamethrin pesticides were uncompetitive, mixed and competitive, respectively.