Neuropharmacological evaluation of methanolic extract of Costus speciosus Linn. rhizome in Swiss albino mice

Abstract

To evaluate the neuropharmacological properties of Costus speciosus (C. speciosus) rhizome using different experimental mouse models. Methods: The anxiolytic effect was investigated by hole-board test, elevated plus maze and light/dark test, while central nervous system (CNS) depressant effect was evaluated by thiopental sodium-induced sleep test. Finally, antidepressant effect was evaluated by forced swimming test and tail suspension test. Results: In both elevated plus maze and hole board test, 400 mg/kg C. speciosus showed more significant CNS depressant effect than 1 mg/kg diazepam. Both 200 mg/kg and 400 mg/kg C. speciosus extract produced a significant dose-dependent decrease in onset of sleep. In forced swimming test, C. speciosus rhizome showed a decrease in duration of immobility in a dose-dependent manner. Imipramine (10 mg/kg) and C. speciosus extract at 400 mg/kg dose exhibited a significant reduction in duration of immobility in tail suspension test which provided additional evidence of antidepressant effect of C. speciosus rhizome. Conclusions: Our study indicates that C. speciosus rhizome possesses CNS depressant, anxiolytic and antidepressant-like activities. Further studies are warranted determine the exact phytoconstituents and mechanism of action responsible for the neuropharmacological effect.