American Journal of Biochemistry 2014, 4(5): 93-97 DOI: 10.5923/j.ajb.20140405.01 Ameliorating Effect of Moringa oleifera Leaf Extract on Chlorpyrifos-Induced Toxicity in the Brain of Wistar Rats Oluwole Israel Oyewole * , Bolanle Fatimat Olabiyi Department of Biochemistry, Faculty of Basic and Applied Sciences, Osun State University, Osogbo, Nigeria Abstract The present study investigated the effects of sub lethal concentration (20 mg/kg bw) of Chlorpyrifos on selected brain parameters (enzymes, protein, histology and antioxidant status) in rats. We also evaluated the possible ameliorating potential of Moringa oleifera leaf extract on Chlorpyrifos-induced oxidative toxicity in rat brain. Eighteen male Wistar albino rats were divided into 3 groups; Group A-control, Group B were administered 20 mg/kg/bw Chlorpyrifos while group C received a combination of 20 mg/kg/bw Chlorpyrifos and 200 mg/kg/bw leaf extract of Moringa oleifera orally for 21 days. Chlorpyrifos caused significant reduction in brain total protein, albumin and globulin while it elevated alkaline phosphatase (ALP) and acid phosphatase (ACP). There was also a significant reduction in reduced glutathione (GSH), glutathione-S-transferase (GST), ascorbic acid, 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. Coadministration of Moringa oleifera leaf extract with Chlorpyrifos caused a significant restoration in brain enzymes and protein as well as restoration of antioxidant capacity. 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 restoration of protein and enzymes status already distorted by chlorpyrifos. Keywords Chlorpyrifos, Moringa oleifera, Antioxidants, Brain histology, Proteins 1. Introduction Epidemiological studies in recent years have shown that exposure of humans to pesticides may increase prevalence of neurological dysfunctions and cancer [1]. It has been estimated that about 3 million cases of pesticide poisoning occur every year resulting in more than 250,000 deaths which may be higher in developing countries where the use of pesticide is particularly widespread due to hot climate condition [2]. Several studies has found significant positive associations between pesticide exposure and brain cancer [3]. Pesticide-induced oxidative stress has been a focus of toxicological research for the last decade as a possible mechanism of toxicity [4]. Several studies have been conducted to determine whether oxidative stress in humans or animals results from various agents in the group and is associated with their toxic effects [5]. Chlorpyrifos (O,O-diethyl O-3,5,6-trichloropyridin-2-yl phosphorothioate) is a crystalline broad-spectrum, * Corresponding author: ioluoye@yahoo.com (Oluwole Israel Oyewole) Published online at http://journal.sapub.org/ajb Copyright © 2014 Scientific & Academic Publishing. All Rights Reserved chlorinated organophosphate insecticide. It was introduced in 1965 by Dow Chemical Company and widely used indoors and outdoors to control fleas, insects, termites, pests and mosquitoes. Unfortunately, this pesticide can get into the body of man unintentionally when touched or inhaled. Many putative mechanisms have been implicated in molecular mechanisms of chlorpyrifos toxicity out of which the induction of oxidative stress has received tremendous attention [6]. The pesticide acts on the nervous system by inhibiting cholinesterase, the enzyme which catalyze the breakdown of acetylcholine, a neurotransmitter [7]. The resulting accumulation of acetylcholine in the synaptic cleft causes overstimulation of the neuronal cells and interference with normal nerve transmission in the brain [8]. A number of medicinal plants have been reported to possess reactive oxygen species (ROS) scavenging and cytoprotective properties. Moringa oleifera leaves has been shown to posses many pharmacological and physiological activities such as antioxidants, anti-inflammatory, analgesic, anti-carcinogenic and cardiotonic effects which account for its usefulness in traditional medicine for a number of disorders [9]. In the present study, we evaluated the effect of Moringa oleifera in Chlorpyrifos induced oxidative stress and toxicity in the brain of wistar rats.