Evaluation of antipsychotic effect of methanolic extract of Ocimum sanctum leaves on laboratory animals

Ocimum sanctum (Lamiaceae) commonly known as tulsi, is well known for its excellent nutritional and medicinal values throughout the world. The present study was undertaken to test the effect of methanolic extract of Ocimum sanctum leaves (50, 100 and 200mg/kg, p.o) on psychosis employing Ketamine induced stereotypic behaviour in mice and Pole climbing avoidance in rats. Haloperidol (1mg/kg, i.p.) and Olanzapine (5mg/kg, i.p.) are established antipsychotic drugs used as standard drugs in the present study. Effect of methanolic extract of Ocimum sanctum leaves (OS), on brain dopamine levels was also estimated. Methanolic extract of Ocimum sanctum leaves (50, 100 and 200mg/kg, p.o), significantly reduced the Ketamine induced falling, weaving, head bobbing and turning behavior in mice. Furthermore, it significantly delayed the latency time taken by the rats to climb the pole. Haloperidol (1mg/kg; i.p.) and Olanzapine (5mg/kg, i.p.) significantly reduced the Ketamine induced stereotypic behavior in mice and condition avoidance behavior in rats. Interestingly, Brain dopamine level was significantly reduced by methanolic extract of Ocimum sanctum leaves. These findings, when taken together indicate that methanolic extract of Ocimum sanctum leaves possesses anti-psychotic like property.