ABSTRACT
Background: Crinum zeylanicum is widely used in the ethno-therapeutic management of folk management of epilepsy, pain, neuropsychiatric, and dementing disorders in Nigeria. The current study was carried out to evaluate the possible mechanism of the memory enhancing the effect of C. zeylanicum extract and alkaloidal rich fraction in Wistar rats. Methods: The effect of Crinum zeylanicum bulb extract (250, 500, and 1000 mg/kg body weight orally), alkaloidal rich fraction (10, 20, and 40 mg/kg body weight p.o.), normal saline (10 ml/kg orally), or Eserine (0.3 mg/kg body weight i.p.) on spatial memory in rats was evaluated using the Y-maze. The blood samples obtained from rats in all treatment groups were evaluated for cholinesterase activities using modified Michelle electrometric method. Results: The extract and the alkaloid significantly (p<0.05) and dose-dependently increased spontaneous alternation behavior of rats in Y-maze. The extract produced 20.00%, 35.55%, and 52.00% inhibition of cholinesterase activity in the blood at 250, 500, and 1000 mg/kg body weight, respectively. The alkaloid produced 56.67%, 62.67%, and 68.67% inhibition of cholinesterase activity in blood at 10, 20, and 40 mg/kg body weight (p.o.). Eserine a standard cholinesterase inhibitor at 0.3 mg/kg body weight produced a significant increase in spontaneous alternation behavior and produced 73.33% inhibition of blood cholinesterase activity. Data obtained from the study showed that the enhanced spontaneous alternation behavior observed in rats treated with the extract, and the alkaloid may be due to facilitation of cholinergic transmission resulting from inhibition of cholinesterase activity. Conclusion: The extract, as well as its partially purified alkaloid, possesses potential that may be employed for therapeutic management of Alzheimer’s disease.