Antipsychotic Activity of Methanol Crude Extracts of Massularia acuminata (G. Don ) Bullock Ex. Hoyle (Rubiaceae) Leaves and Stem Bark in Mice

Abstract

Massularia acuminata (Rubiaceae) is a plant native to Western Africa's tropical regions that has been documented in ethnobotanical surveys as a herbal treatment for psychosis. However, no reports on its antipsychotic activity have been found. Thus, this study was conducted to evaluate the antipsychotic activity of M. acuminata leaves and stem bark. Graded doses of methanol extract of M. acuminata leaves and stem bark (125, 250, 500 mg/kg), and 0.2 mg/kg Haloperidol were administered to different groups of male Swiss albino mice orally an hour prior to intraperitoneal administration of Ketamine (30 mg/kg), for 10 days. A negative control group received only Ketamine (30 mg/kg) daily. The animals observed for hyperlocomotion activity in an open field chamber, stereotype behaviour in a transparent chamber, and subjected to a Forced Swim Test to detect the effects of the extracts on positive and negative psychotic symptoms. The statistical analysis was carried out using one-way ANOVA, followed by the Dunnett's Post hoc test at p < 0.05. Massularia acuminata leaves and stem bark extracts gave a dose-dependent decrease in the number of lines crossed compared to Haloperidol. The stem bark and leaf extracts gave a calming effect at different doses, by reducing repetitive behaviours in the mice. Also, both extracts reduced the immobility time in the Forced Swim test. The leaves and stem bark extracts of M. acuminata were found to be effective against the positive and negative symptoms of psychosis, hence justifying the traditional usage of the plant in treating mental illness.