Screening of Antianxiety Activity of Extracts and Fractions of Verbena officinalis Aerial Parts

Abstract

Verbena officinalis L. (Vervain; family-Verbenaceae) has been traditionally used in the treatment of various ailments especially in mental disorders, but no systematic work has been carried out to validate traditional claims of plant. Therefore, it was planned to screen antianxiety activity of extracts and fractions of V. officinalis aerial parts. Crude extracts of V. officinalis aerial parts were prepared by extracting the plant material successively with n-hexane, chloroform, methanol and water. The antianxiety activity of crude extracts was performed at the doses of 200 or 400 mg/kg, p.o., upon acute administration in mice using elevated plus maze model. The bioactive extract was partitioned using ethyl acetate, and ethyl acetate fraction (50 or 100 mg/kg, p.o.) and remaining bioactive extract (150 or 300 mg/kg, p.o.) were also screened for antianxiety activity. The statistical significance was checked by comparing with standard drug and control using one way analysis of variance (ANOVA), which was followed by post hoc analysis – StudentNewman-Keul’s test. The methanol extract and ethyl acetate fraction exhibited significant antianxiety activity at the dose of 400 mg/kg and 100 mg/kg, respectively, with respect to control and statistically equivalent to the standard drug (Diazepam, 2 mg/kg, p.o.). The bioactive ethyl acetate fraction is rich in phenolic compounds and flavonoids. Finally, it is concluded that these are major anxiolytic constituents of V. officinalis.