Journal of Pharmaceutical Research International

Background: Alzheimer’s disease and related cognitive disorders are characterized by progressive impairment of learning and memory, often associated with cholinergic dysfunction. Natural plant-derived compounds are being explored as potential nootropic agents with neuroprotective properties. Therefore, this study was undertaken to evaluate the nootropic potential of the ethanolic leaf extract of Couroupita guianensis (ELECG) in mice.

Methods: The nootropic activity of ELECG was assessed at selected dose levels using established behavioral models of learning and memory. Donepezil was used as the standard reference drug, while Scopolamine (1 mg/kg, i.p.) was administered to induce experimental amnesia. Cognitive performance was evaluated using the Elevated Plus Maze, Radial Arm Maze, and Y-maze paradigms in scopolamine-induced amnesic mice. Brain acetylcholinesterase (AChE) activity was estimated in whole-brain homogenates to assess cholinergic function.

Results: Treatment with ELECG significantly improved behavioral performance and increased spontaneous alternation behavior in the Y-maze test from 20.83 ± 3.81% in the disease control group to 71.14 ± 14.49% (p < 0.01) and 77.38 ± 11.42% (*p < 0.001) at 400 mg/kg, indicating enhancement of spatial working memory. In the Elevated Plus Maze model, ELECG significantly reduced transfer latency and memory errors in scopolamine-treated mice, with working memory errors decreasing from 4.9 ± 0.52 in the disease control group to 1.6 ± 0.24 (p < 0.01) at 400 mg/kg, suggesting improved learning and memory retention. The extract also enhanced locomotor activity and markedly reduced brain AChE activity from 3.03 ± 0.11 in the disease control group to 2.20 ± 0.12 (p < 0.01) at 400 mg/kg, comparable to donepezil treatment (1.95 ± 0.08; p < 0.01), indicating restoration of cholinergic neurotransmission disrupted by scopolamine.

Conclusion: These findings demonstrate that ELECG enhances learning and memory across multiple experimental paradigms. The reduction in brain AChE activity further supports its neuroprotective and cognition-enhancing effects. Therefore, the leaf extract of Couroupita guianensis may represent a promising therapeutic candidate for the management of Alzheimer’s disease and related cognitive disorders.