ABSTRACT
The leaves ofZiziphus mauritiana have been reported to be used in the management of depressive illnesses in traditional medicine. The antidepressant activity of the methanol leaf extract of the plant was evaluated using tail suspension test (TST) and forced swim test (FST) at the doses of 25, 50, 100, and 200 mg/kg.Imipramine (20mg/kg) was used as standard antidepressant drug.The effect of the extract on recognition memory, motor coordination, and exploration was evaluated using novel object recognition test (NORT), beam walking assay test (BWAT) and open field test (OFT) respectively. In order to establish the involvement of inflammatory system in the antidepressant activity of the extract using Bacillus Calmette-Guérin(BCG) induced depressive like behaviour modelthrough chronic activation of the immune system in the chronic study, mice were inoculated with BCG (0.2 mg/kg, i.p) and later treated with the graded doses of the extract for 21 days. Body weight was measured 4 days before the inoculation and on daily based after, while the body temperature was recorded hourly. Exploration, immobility time and sucrose consumption were all assessed using open field test, tail suspension test and sucrose preference test respectively.Data wererepresented asÂ� SEM and analyzed using one-way (treatment) or two-way (treatment �“ time) analysis of variance (ANOVA), followed by the Bonferroni post hoc test whereP< 0.05 was considered significant .The results showed a statistical significant ( p < 0.001) decrease in duration of immobility, significant (p < 0.001) increase in sucrose consumption,significant (p < 0.001) decrease in body temperature,significant (p < 0.001) increase in body weight in the extract treated groups when compared with the BCG + distilled water. The LD50 of the extract was >5000 mg/kg and phytochemical screening revealed the presence of flavonoids, alkaloids, tannins, cardiac glycoside, and saponins. It was concluded that the methanol leaf extract of Ziziphus mauritiana possesses antidepressant activity, it also attenuated anhedonia, reversed body weight loss and produced antipyretic effect induced by BCG induced depressive like behaviour.