Objective: 

Chlorpyrifos (CPF) is an organophosphate that is widely used as an insecticide. It has been reported that CPF enhance the production of reactive oxygen species (ROS), and it alters the enzyme activities associated with antioxidant defense mechanisms in different tissues of rats. Quercetin and catechin are the most common flavonoids in the human diet and, like other flavonoids, have been shown to potent free radical scavengers and antioxidant.

Methods: 

The mature male Wistar rats (n=36) were divided into six groups having six animals, i.e., Group I (control), Group II (catechin, 20 mg/kg bw), Group III (quercetin, 20 mg/kg bw), Group IV (chlorpyrifos 5.4 mg/kg), Group V (catechin+chlorpyrifos) and Group VI (quercetin+chlorpyrifos). Rats were given chlorpyrifos, catechin and quercetin daily via gavage for 4 weeks.

Results: 

In the chlorpyrifos, catechin plus and quercetin plus chlorpyrifos treated groups, there were increased the levels of malondialdehyde (MDA) content, and decreased superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activities in brain tissues compared to the control group. Whereas, when catechin plus and quercetin plus chlorpyrifos- treated groups compared to chlorpyrifos treated group, there were significantly decreased in MDA content and increased SOD, CAT, GPx and GST activities.

Conclusions: 

In the present study, even though chlorpyrifos was given at 1/25 of the oral LD50, we observed changes in the antioxidant enzyme activities and MDA content in rat brain tissues. The antioxidant properties of flavonoids may scavenge some radical species. Thus, it appears that catechin and quercetin ameliorate chlorpyrifos-induced neurotoxicity but are not completely protective.