Antidepressant-like activity of methanol leaf extract of Ziziphus mauritiana lam in mice: Involvement of anti-inflammatory mechanism

Abstract

The leaves of Ziziphus mauritiana have been reported to be used in the management of depressive illnesses in traditional medicine in Northern Nigeria. Previous studies have reported the antidepressant potential of the leaves of Z. Mauritania. The present study, therefore was designed to establish the involvement of inflammatory system in the antidepressant activity of the extract using Bacillus Calmette-Guérin (BCG) induced depressive-like behaviour model. Mice were administered with BCG (0.2 mg/kg, i.p) followed by graded doses of the extract (25, 50, 100 and th 200 mg/kg) for 21 days. Body weight and temperature were assessed on daily basis. Exploratory behaviour (at 4^th ,  8^th , 24^th and 48 hours), immobility time (at 7^th , 14^th and 21^st day) and sucrose preference (at 7^th and 21^st day) were all assessed using open field test, tail suspension test and sucrose preference test, respectively. Significant increase in body weight (p < 0.01), decrease in body temperature(p < 0.001), increase in number of line crossing (p < 0.001), decrease in immobility time (p < 0.001) and increase in sucrose consumption(p < 0.001), were observed in a dose non-dependent manner, in the extract treated groups. It may be concluded therefore that the antidepressant activity of methanol leaf extract of Ziziphus mauritiana may possibly involve an anti-inflammatory mechanism.