Anti-psychotic effects of leaf extracts of Palisota hirsute (Thunb.) K. Schum. (Commelinaceae) and Costus afer Ker-Gawl (Zingiberaceae) on ketamine-induced psychotic mice

Abstract

This study assessed the anti-psychotic activity of the methanol leaf extracts of Palisota hirsute (Thunb.) K. Schum. (Commelinaceae) and Costus afer Ker-Gawl (Zingiberaceae) in Ketamineinduced psychotic mice. Antipsychotic activity of the two plant extracts (Palisota hirsuta and Costus afer) at different doses were assessed using the Ketamine animal model of psychosis. Locomotor and stereotype behaviours were studied in an open-field and transparent chambers, while the force swim test was investigated in a cylindrical glass containing water. From the locomotion test, both doses of the plant extracts tested for activity showed a significant reduction in hyperactivity. Palisota hirsuta and Costus afer (500 mg/kg) antagonised the stereotypy effect induced by Ketamine in the mice. Furthermore, the two doses of Palisota hirsuta (250 and 500 mg/kg) and Costus afer at 500 mg/kg had high anti-depressant activity in that the immobility time recorded during the force swim test was reduced significantly. Palisota hirsuta extract had a good anti-psychotic effect at both the higher (500 mg/kg) and lower doses (250 mg/kg), whereas Costus afer extract had a greater anti-psychotic effect at a higher dose of 500 mg/kg than at a lower dose and these results are similar to those of the positive control drug (Haloperidol).