Antipsychotic Effect of the Leaves of Stachytarpheta Cayennensis (l.C. Riche) Vahl. Verbenaceae in Mice.

The antipsychotic effect of the extracts of the leaves of Stachytarpheta cayennensis was examined following ethnomedicinal claims for its use in the management of mental illness in Nigeria, Ghana and other tropical parts of the globe. The apomorphine and amphetamine-induced stereotyped behavior models were used in this study to see if the extract or its fractions would abolish the stereotypy in mice. The method of Siqueira et al (1998) was employed in this study and the Kruskal Wallis non parametric ANOVA followed by Mann-Whitney U-test was employed for statistical analysis.The results showed that only the methanolic extract of the leaves of Stachytarpheta cayennesis but none of the fractions thereof prevented stereotyped behavior induced by amphetamine. The extract did not abolish stereotypy induced by apomorphine. The inhibition of amphetamine stereotypy also occurred at only one dose (20 mg/kg, i.p.).The inferences from this study include the fact that for the antipsychotic effect of the leaves of stachytarpheta cayennesis , fractionation would lead to loss of activity. More importantly the methanolic extract of the leaves of Stachytarpheta cayennensis possesses antipsychotic effect and this justifies its ethnomedicinal use in the management of mental illness in some regions of the world. Keywords: Antipsychotic; Stachytarpheta cayennensi s; amphetamine; apomorphine; stereotypy