Phytochemical investigation, in vitro antioxidant, and in vivo antidepressant activity of ethanolic leaf extract Antigonon leptopus

Abstract

Aim: The present investigation deals with the preliminary phytochemical screening, in vitro antioxidant, and in vivo antidepressant activity of ethanolic leaf extract of Antigonon leptopus. Materials and Methods: In vitro antioxidant activity was evaluated using the parameters such as free radical scavenging using phosphomolybdenum antioxidant assay, nitric oxide scavenging activity, and hydrogen peroxide scavenging. Ascorbic acid (AA) with the same concentration was used as an standard antioxidant. Extract was investigated further for its antidepressant activity using the forced swim test, tail suspension test, and locomotor activity using digital photoactometer. AA, fluoxetine (10 mg/kg), and imipramine (4 mg/kg, p.o) were used as reference drugs for comparison in the antioxidant and antidepressant experiments, respectively. Results and Discussions: Preliminary phytochemical screening of the extracts revealed the presence of alkaloids, carbohydrates, glycosides, phenolic compounds, tannins, saponins, and flavonoids. The presence of these bioactive constituents is associated with the antioxidant and antidepressant activity of the plant. The IC50 values of nitric oxide and hydrogen peroxide radicals were found to be 216 and 20.8 ug/ml for extract and 24.54 and 33.1 ug/ml for AA. It has been observed from our study that the extract showed significant (P < 0.01) reduction in immobility in tail suspension and forced swim model of depression comparable to imipramine. In locomotor activity testing, it showed psychostimulant effect comparable to that of standard fluoxetine. Conclusion: The results indicated that dose-dependent in vitro antioxidant activity against phosphomolybdenum antioxidant assay, nitric oxide scavenging activity, and hydrogen peroxide scavenging by ethanolic leaf extract of A. leptopus comparable with that of standard AA. The antioxidant and antidepressant effect of A. leptopus seems to be mediated due to the presence of various phytochemical constituents.