Acute in vivo evaluation of the antidepressant-like activity of the aerial methanol extract of Alysicarpus glumaceus (Vahl) DC. and its fractions

Abstract

Depression is one of the most prevalent psychiatric disorders with complex and heterogeneous pathology and symptoms. Current classes of agents used in the management of depression are associated with a number of shortcomings. In Africa, some patients with depression use medicinal plants; however, evidence on the beneficial effects of these remedies remains limited. Alysicarpus glumaceus (AG) (family Leguminosae) is used in the management of depression in Nigeria. This study was undertaken to evaluate the antidepressant activity of the methanol extract (ME) of AG and its fractions in mice. The antidepressant-like activity of the extract and its fractions at 500, 1000 and 1500 mg/kg was evaluated using tail suspension test (TST) and forced swim test (FST). Stimulant activity was evaluated using a digital actophotometer while the novel object recognition test (NORT) was used to assess memory. Methanol Extract of Alysicarpus glumaceus reduced the duration of immobility following TST and FST in a dose-dependent manner. Only the extract at 1500 mg/kg significantly (p˂0.01) and all the test doses of the extract significantly (p˂0.05) reduced the duration of immobility in TST and FST respectively. However, the reduction produced by the fractions were not dose dependent. There was a non-significant decrease in spontaneous locomotor activity of ME and some fraction-treated groups, thus arguing against a general stimulant effect. Similarly, in the NORT, both the ME and its fractions (except hexane and residual aqueous fractions at 1500 mg/kg; and ethyl acetate fraction at 500 and 1000 mg/kg) had no effect on recognition memory after acute administration. In conclusion, the aerial ME of Alysicarpus glumaceus possesses antidepressant-like activity.