Neurophysiological Investigation of the Cognitive-Enhancing Effects of Ethanolic Plant Extracts in Male Swiss Albino Mice and Rats

Abstract

The present study investigates the neurophysiological basis of the cognitive-enhancing effects of ethanolic extracts of Crinum asiaticum (EECA) and Crinum defixum (EECD) in male Swiss albino mice (18–22 g) and rats (150–200 g). The extracts, prepared by Soxhlet extraction with 50% ethanol, were administered orally at doses of 200 and 400 mg/kg. Piracetam (200 mg/kg, p.o.) served as the reference standard. Learning and memory functions were assessed using behavioral paradigms such as the Elevated Plus Maze (EPM), scopolamine-induced amnesia (SIA), and diazepam-induced amnesia (DIA), while neurotransmitter-related physiological responses were evaluated through clonidine-induced (noradrenergic) hypothermia (CIH), lithium-induced (serotonergic) head twitches (LIH), and haloperidol-induced (dopaminergic) catalepsy (HIC). EECA and EECD significantly increased the inflexion ratio in EPM, SIA, and DIA, indicating improved acquisition and retention of memory. Both extracts also normalized body temperature in the CIH model and reduced lithium-induced head twitches, suggesting modulation of central adrenergic and serotonergic activity. However, no significant change was observed in haloperidol-induced catalepsy, indicating limited dopaminergic involvement. The findings indicate that the cognitive-enhancing activity of EECA and EECD may involve cholinergic, GABAergic, adrenergic, and serotonergic pathways. The presence of bioactive flavonoids and alkaloids in these extracts may underlie their neuroprotective and memory-facilitating properties. Overall, the study supports the physiological role of Crinum species in improving cognitive function.