Investigation of in vivo neuropharmacological effect of Alpinia nigra leaf extract.

ABSTRACT

OBJECTIVE: To analyze in vivo neuro-pharmacological effects of Alpinia nigra as anxiety is a particular form of behavioral inhibition that occurs in response to novel environmental events. METHODS: In present study, the extract of Alpinia nigra was evaluated for its central nervous system depressant effect using mice behavioral models, such as hole cross, open field and thiopental sodium induced sleeping time tests for its sedative properties and an elevated plus-maze test for its anxiolytic potential, respectively. RESULTS: In anxiolytic study, the extract displayed increased percentage of entry into open arm at the dose of 400 and 200 mg/kg. The extract produced a significant (P<0.01) increase in sleeping duration and reduction of onset of sleep compared to sodium thiopental at both doses (200 and 400 mg/kg). The extract (200 and 400 mg/kg) also showed a dose-dependent suppression of motor activity and exploratory activity of the mice in both open field and hole cross test. CONCLUSION: This study demonstrates that the treated extract has significant central nervous system depressant effect. Further studies on active constituent of the extract can provide approaches for therapeutic intervention.