Evaluation of Nootropic Activity of Selected Plant Extract in Mouse Model

Abstract

The present study evaluated the nootropic activity of methanolic extract of Vigna angularis (adzuki bean) in scopolamine-induced amnesia in Swiss albino mice. Phytochemical screening revealed the presence of alkaloids, flavonoids, phenols, tannins, saponins, terpenoids, steroids, and glycosides, compounds known for their neuroprotective and antioxidant roles. Acute oral toxicity studies conducted as per OECD 423 guidelines confirmed that the extract was safe up to 2000 mg/kg (LD₅₀ cut-off > 2000 mg/kg), enabling the selection of test doses (50, 100, 200 mg/kg) for pharmacological evaluation. In behavioral studies, scopolamine caused memory impairment as evidenced by prolonged transfer latency in the Elevated Plus Maze, reduced spontaneous alternation in the Y-Maze, and impaired learning and retention in the Morris Water Maze. Administration of Vigna angularis extract significantly improved these deficits in a dose-dependent manner, with medium and high doses showing effects comparable to Piracetam (100 mg/kg). Biochemical analysis supported the behavioral findings. Scopolamine increased acetylcholinesterase (AChE) activity, malondialdehyde (MDA), and nitric oxide (NO) levels, while decreasing antioxidant enzymes (SOD, CAT, GPx). Treatment with Vigna angularis extract reduced AChE activity and oxidative stress markers while enhancing antioxidant enzyme activities, restoring redox balance and cholinergic function. Histopathological examination of the hippocampus revealed that scopolamine induced neuronal degeneration, cell loss, and vacuolization. Extract-treated groups demonstrated marked neuroprotection, with high-dose Vigna angularis showing neuronal integrity comparable to Piracetam and normal controls.