Evaluation of the effect of single and repeated dose administration of alkaloid, non-alkaloid and crude extracts of khat (Catha edulis Vahl. Endl.) on spatial learning and memory in mice

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Addis Ababa University


Khat (Catha edulis Vahl. Endl.), an ever green shrub that belongs to the family Celastraceae, is chewed by millions of people in Ethiopia, Yemen, Somalia, Djibouti and Kenya for its psychoactive effects. Besides its use as a social and recreational stimulant, supporters of khat chewing claim that it improves performance and memory, make them alert and think clearly. Although such beliefs are widely held, little is known about the effect of khat on spatial learning and memory. Recent studies done to evaluate the effect of crude extract of khat leaves in mice have shown variable effects on learning and memory. Thus, this study was initiated to investigate the effect of alkaloid and non-alkaloid fractions as well as crude khat extract on spatial learning and memory. To this effect, mice 6-8 weeks old (5-6 per group), were administered orally with either a single dose or repeated daily doses (5-7days) of alkaloid (50 mg/kg, 100 mg/kg) and non-alkaloid (50 mg/kg, 100 mg/kg) fractions as well as crude khat extract (100 mg/kg, 200 mg/kg, and 400 mg/kg) according to their respective groups. Controls were administered with 0.5 ml 2% Tween 80 in water. The animals were then subjected to Multiple T-maze (MTM) and Morris water maze (MWM) task performance, and parameters (latency and number of wrong decisions) related to learning and memory were assessed. The result showed that single and repeated dose administration of alkaloid and non-alkaloid fractions as well as crude khat extract at doses used did not have a significant effect on learning, short and long term memory using the two models. In general, during the four training days, there was a decrease in both latency and number of wrong decisions indicating both the test groups and controls learned the task in both models of the study. The results collectively indicate that neither the fractions nor the crude extract had significant effect on learning and memory.



Catha edulis Vahl. Endl, Latency, Learning, Memory, Morris water maze, Multiple T-maze, White albino mice, Wrong decision.