Abstract: 
The leaf of Carpolobia lutea G. Don (Polygalaceae) is widely used among the Ibibio and Efik in Nigeria to control psychotic patient by sedation. This antipsychotic effect among other uses of the plant is yet to be investigated pharmacologically. This is a first report of neuropharmacological screening of the leaf. Gradient extraction was executed after maceration of air-dried leaf of C. lutea in n-hexane, chloroform, ethyl acetate and ethanol solvent for 72 hours to obtain the four fractions. The effects of these four fractions of the leaf (192.5-770mg/kg) were investigated on thiopentol-induced sleeping time, locomotor activity, pentylenetetrazole (PTZ) – and strychnine (STN)-induced convulsion in mice. The most active fraction, ethyl acetate fraction, was submitted to semi- preparative HPLC to structurally isolate and characterized active compounds. The ethyl acetate fraction reveal a dose dependent significant (P < 0.01) prolongation of sleeping time duration but no effect on sleeping time latency when compared with control group. The ethyl acetate fraction reveals a dose dependent significant (p < 0.05- 0.001) decrease on locomotor activity. In the anticonvulsant assay, it demonstrates 60% and 40% protection in the PTZ- and strychnine-induced convulsion in mice respectively. The effects of other fractions were not as significant compared to the ethyl acetate fraction. Five polyphenols were isolated, the first four molecules is reported for the first time. The neuropharmacological screening results and isolated compounds could in part lend credence to antipsychotic ethnomedical uses of C. lutea in management of mad people in Akwa Ibom State of Nigeria.

Keywords: Carpolobia lutea, Psychopharmacology, Neuropharmacology, Anticonvulsant.