Neuropharmacological activity of the aqueous leaf extract of Croton zambesicus (euphorbiaceae) in some laboratory animals

 To determine the neuropharmacological activity of the leaf extract of Croton zambesicus in mice and chicks. The effect of aqueous leaf extract of Croton zambesicus on thiopental sodium – induced sleeping time in mice, on gross locomotor activity (GLA) in 2-day old chicks and effect of extract on apomorphine - induced stereotyped behavior in chicks were evaluated. The aqueous extract (1000 and 1500 mg/kg), administered per os (p.o), prolonged the thiopental sodium - induced sleeping time in mice.   Extract (20-40 mg/kg i.p) produced a significant ( P < 0.05) decrease in GLA in 2-day old chicks in a dose dependent manner. 40-60 mg/kg administered intraperitoneally (i.p) produced sedation and sleep with a significant ( P < 0.05) decrease in onset and an increase in duration of sleep. The extract had an insignificant (P > 0.05) effect on apomorphine - induced stereotyped behavior in chicks.    These results suggest that leaf extract of Croton zambesicus possesses CNS depressant, sedative, and hypnotic activity.