TOXICITY ASSESSMENT OF CHLORPYRIFOS AND POSSIBLE PROTECTIVE ROLE OF MORINGA OLEIFERA LEAF EXTRACT
O.I. OYEWOLE and ARISE R.O.
Department of Biochemistry, Osun State University, Osogbo Nigeria Department of Biochemistry, University of Ilorin, Nigeria
Abstract:
Epidemiological studies have shown that exposure of humans to pesticides may increase prevalence of neurological dysfunctions and cancer. Chlorpyrifos is a broad spectrum organophosphate insecticide widely used in agriculture. The pesticide exhibit toxicity by inhibiting acetyl cholinesterase enzyme thereby interfering with normal nerve transmission. It also induce oxidative stress by depleting antioxidant capacity in the brain. The present study investigated the effects of sub lethal concentration (20mg/kg bw) of Chlorpyrifos on selected blood immunological parameters, brain histology, oxidative stress and antioxidant status in rats. The study also evaluated the possible protective effects of Moringa oleifera leaf extract on Chlorpyrifos-induced toxicity in rat. Twenty four male Wistar albino rats were used and divided into 3 groups. Group 1 served as the control; Group 2 were administered 20mg/kg/bw Chlorpyrifos while group 3 received a combination of 20mg/kg/bw Chlorpyrifos and 200mg/kg/bw leaf extract of Moringa oleifera orally for 21 days. Chlorpyrifos caused significant reduction in plasma total protein and total immunoglobin. There was also a significant reduction in reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) as well as elevated malondialdehyde (MDA) level in the brain of the rats administered the pesticide. In addition, Chlorpyrifos significantly distorted brain histology as characterized by mild development of amyloid plaques and spongy architecture due to vacuole formation in the neurons. Coadminsistration of Moringa oleifera leaf extract with Chlorpyrifos caused a significant boost in blood plasma protein and immunoglobulin as well as elevation of brain antioxidant enzymes (CAT, SOD and GSH). Brain architecture was also well preserved in rats who received the drug combination. We conclude that Moringa oleifera leaf significantly reduced chlorpyrifos-induced oxidative stress in rat brain in addition to boosting of immune status already depleted by Chlorpyrifos in rats.