Role of aqueous extract of Azadirachta indica leaves in an experimental model of Alzheimer's disease in rats

BACKGROUND: Alzheimer's disease (AD), a progressive neurodegenerative disorder characterized by multiple cognitive deficits, is often accompanied by behavioral disorders and mood changes. Because of the non-availability of proper curative/preventive therapy for AD, the present study was designed to evaluate the possible role of Azadirachta indica in experimental AD in rats. MATERIALS AND METHODS: Experimental AD in rats was produced by nucleus basalis magnacellularis lesion with ibotenic acid (IB) and intacerebroventricular administration of colchicine (Col). Different behavioral tests and biochemical analysis were performed to explore the role to A. indica in AD. RESULTS: A. indica exhibited anxiolytic activity in the open field test in Col lesion animals, which was comparable to that of diazepam. In the Elevated plus maze test, A. indica significantly alleviated IB and Col-induced anxiety. IB and Col-induced depression was mitigated by A. indica, and the results were comparable to that of imipramine. In Morris’ water maze test, A. indica pre-treatment improved reference memory, working memory and spatial learning, which are at par with the effects of donepezil. Both IB and Col-induced deficits in active avoidance learning and retention of learned behavior were significantly reversed by A. indica. IB and Col-induced increased lipid peroxidase activity was significantly reversed by A. indica (reductions in malondialdehyde level). A. indica stabilized rise in superoxide dismutase and a decreasing trend in acetylcholine-esterase (AChE) activity was seen with IB and Col lesions. A. indica had no effect over the AChE activity. CONCLUSION: A. indica might be effective in clinical AD by virtue of its cognition enhancement, antidepressant and antianxiety properties.