Central nervous system depressant activity of ethanol extract of Motandra guineensis (Thonn) AD. aerial parts in mice

Abstract

BackgroundMotandra guineensis Thonn AD. (Apocynaceae) is used for the management of pain and as a sedative in the treatment of insanity in Nigerian traditional medicine. The study investigated the neuropharmacological activities of the aerial parts of M. guineensis in mice. MethodsClassical models of tail suspension, forced swim, open field, hole board, elevated plus maze, and sodium pentobarbital-induced sleeping time tests were employed and the extract was administered at doses of 50,100 and 200 mg/kg, p.o. Oral acute toxicity test was done at the dose of 2000 mg/kg. The extract was also subjected to phytochemical tests and GC–MS analysis. ResultsIn tail suspension test, the extract at the dose of 200 mg/kg significantly reduced immobility time of mice compared to control while in the forced swim test, immobility time of the mice decreased in a dose-dependant manner. In the open field test, there was a significant and dose-dependant reduction in the number of lines and squares crossed compared with control. The number of head dips in the hole-board test was decreased in the extract treated groups compared to control. The extract significantly increased the time spent in the open arms of elevated plus-maze apparatus at higher doses (100 and 200 mg/kg) compared to control. The phenobarbitone-induced sleeping time was prolonged by the extract at all doses compared to control. There was no death recorded for the extract at the dose of 2000 mg/kg. ConclusionThe results indicate possible CNS depressant effect of the ethanol extract of M. guineensis, thus support the use of the plant as a sedative in the treatment of insanity in Nigerian traditional medicine.