Comparative Neuroprotective Study on Scopolamine-Induced Alzheimer’s-Like Cognitive Deficits in Rats

Abstract

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by memory loss, cognitive impairment, oxidative stress, and cholinergic dysfunction. The present study was designed to evaluate and compare the neuroprotective effects of Bacopa monnieri and Centella asiatica against scopolamine-induced Alzheimer’s-like cognitive deficits in rats. Wistar rats were divided into seven groups, including normal control, scopolamine control, standard drug-treated (donepezil), and treatment groups receiving low and high doses of Bacopa monnieri and Centella asiatica. Cognitive function was assessed using the Morris Water Maze (MWM) and Y-Maze tests. Biochemical parameters such as acetylcholinesterase (AChE), lipid peroxidation (MDA), superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), and total protein were estimated. Histopathological examination of brain tissue was also performed. Scopolamine administration resulted in significant cognitive impairment, increased AChE activity and lipid peroxidation, and decreased antioxidant enzyme levels and total protein, confirming induction of Alzheimer-like pathology. Treatment with both plant extracts significantly improved behavioral performance, reduced AChE activity and MDA levels, and restored antioxidant enzymes and protein levels in a dose-dependent manner. Histopathological findings revealed reduced neuronal degeneration and improved brain architecture in treated groups. Comparative evaluation indicated that Bacopa monnieri exhibited superior neuroprotective activity compared to Centella asiatica, particularly at higher doses, with results comparable to the standard drug donepezil. In conclusion, the findings suggest that both Bacopa monnieri and Centella asiatica possess significant neuroprotective and cognitive-enhancing properties, with Bacopa monnieri emerging as a more potent therapeutic candidate for the management of Alzheimer’s disease.

Keywords: Alzheimer’s disease, Bacopa monnieri, Centella asiatica, Scopolamine, Neuroprotection, Antioxidant, Memory.