Anxiolytic and Antidepressant Effects of Maerua angolensis DC. Stem Bark Extract in Mice.

Introduction: The stem bark extract of Maerua angolensis DC. (Capparaceae) is used as a traditional remedy for management of anxiety, psychosis, and epilepsy.

Aim of the study: We therefore aimed at evaluating the anxiolytic and antidepressant potential of the plant in mice models.

Methods: The dried stem bark was extracted with petroleum ether/ethyl acetate (50:50) mixture to obtain the extract, MAE. We employed Irwin's test to identify the preliminary behavioral and autonomic effects. Subsequently, MAE was administered per os to male mice and subsequently assessed, 1 h later, for anxiety parameters in the elevated plus maze (EPM) and the regular Suok tests. The forced swim (FST) and tail suspension (TST) tests were employed to assess the antidepressant potential of the extract (100-1000 mg kg^-1).

Results: In our preliminary assay, MAE (100-5000 mg/kg) exhibited analgesic effects and a reduction in fear response in the Irwin's test. The spontaneous locomotor activity was reduced at 1000 mg/kg. Additionally, MAE (1000 mg/kg) increased the latency to PTZ-induced convulsions, and duration to sleep in the pentobarbitone induced sleeping time assay. MAE (1000 mg/kg), similar to diazepam, in the anxiolytic assay, increased the percentage time spent in the open arms while decreasing protected head dips and unprotected stretch attend postures in the EPM. Correspondingly, there was a reduction in anxiety-induced immobility and freezing in the Suok test (300 mg/kg) without loss of sensorimotor coordination. Additionally, there was a significant reduction in immobility duration in the FST (300 mg/kg) and TST (1000 mg/kg).

Conclusion: The petroleum ether/ethyl acetate fractions of Maerua angolensis stem bark possess anxiolytic and acute antidepressant effects in mice.