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 dysfunction, oxidative stress, cholinergic deficit, and neuronal degeneration. This review focuses on the comparative neuroprotective effects of Bacopa monnieri (Brahmi) and Centella asiatica (Gotu Kola) in experimental models of scopolamine-induced Alzheimer’s-like cognitive impairment in rats. Both herbs are traditionally used to enhance memory and intellect, and possess rich phytochemical profiles, including bacosides in Bacopa monnieri and asiaticoside/asiatic acid in Centella asiatica. Experimental findings indicate that both extracts significantly improve learning and memory in behavioral paradigms such as the Morris Water Maze, Y-Maze, and Novel Object Recognition tests. Mechanistically, they attenuate scopolamine-induced oxidative stress by elevating endogenous antioxidant markers (SOD, CAT, GSH) and reducing lipid peroxidation (MDA). Moreover, both extracts exhibit cholinesterase inhibitory activity, thereby restoring acetylcholine levels in the hippocampus. Histopathological studies demonstrate reduced neuronal damage and improved hippocampal integrity following treatment. Comparative studies suggest that while Bacopa monnieri shows stronger cholinesterase inhibition due to its bacoside content, Centella asiatica provides higher antioxidant and neuro-regenerative benefits through asiaticosides. Collectively, the findings support the potent neuroprotective and cognition-enhancing properties of these medicinal plants, highlighting their potential as complementary therapies for Alzheimer’s disease prevention and management.

Keywords: Bacopa monnieri; Centella asiatica; Alzheimer’s disease; Scopolamine; Cognitive impairment; Neuroprotection.