Pharmacological Evaluation of Neuroprotective Potential of Nelumbo Nucifera (Red Flower) Extract in Experimental Alzheimer’s Disease in Rats

Abstract

Alzheimer’s disease is a progressive neurodegenerative disorder characterized by cognitive decline, memory impairment, cholinergic dysfunction, and oxidative stress. The present study was undertaken to evaluate the neuroprotective potential of the red flower extract of Nelumbo nucifera in an aluminium chloride (AlCl₃)-induced experimental model of Alzheimer’s disease in Wistar albino rats. The red flower extract was prepared and subjected to preliminary phytochemical screening, which revealed the presence of flavonoids, alkaloids, phenolic compounds, tannins, glycosides, saponins, and terpenoids. An acute oral toxicity study conducted according to OECD guidelines demonstrated that the extract was safe up to 2000 mg/kg body weight. Based on this, doses of 100, 200, and 400 mg/kg were selected for the study. The animals were divided into six groups, including normal control, disease control, standard drug-treated group, and extract-treated groups. Cognitive function was assessed using the Morris Water Maze and Y-maze tests. The disease control group showed significant impairment in learning and memory, whereas treatment with Nelumbo nucifera extract significantly improved cognitive performance in a dose-dependent manner. Biochemical estimations revealed that aluminium chloride administration significantly increased acetylcholinesterase activity and lipid peroxidation (MDA levels), while decreasing antioxidant enzymes such as superoxide dismutase, catalase, and reduced glutathione. Treatment with Nelumbo nucifera extract significantly reversed these alterations, indicating restoration of cholinergic function and antioxidant defense. The extract also improved total protein levels, suggesting protection of neuronal integrity. Among the tested doses, the 400 mg/kg dose exhibited maximum neuroprotective effect and showed results comparable to the standard drug Donepezil. The observed effects may be attributed to the presence of bioactive phytoconstituents with antioxidant and cholinesterase inhibitory properties. In conclusion, the present study demonstrates that Nelumbo nucifera red flower extract possesses significant neuroprotective and anti-Alzheimer activity. It may serve as a promising natural therapeutic agent for the management of Alzheimer’s disease. Further studies are required to elucidate its mechanism of action and clinical applicability.

Keywords: Nelumbo nucifera; Neuroprotection; Alzheimer’s disease; Acetylcholinesterase inhibition