BEHAVIORAL AND BIOCHEMICAL EVIDENCES FOR ANTIDEPRESSANT ACTIVITY OF ETHANOL EXTRACT OF Jatropha curcas IN MICE SUBJECTED TO CHRONIC UNPREDICTABLE MILD STRESS

Jatropha curcas is a multipurpose herbal plant commonly found in tropical areas, such as Africa. Traditionally the leaves are used in treatment of psychotic illness and depression. There is dearth of information on the antidepressant effect of J. curcas leaves. Hence, this study was design to evaluate the anti-depressant property using acute and chronic models of depression. The acute models include forced swim test (FST), tail suspension test (TST), locomotor activity, yohimbine-induced lethality test and reserpine induced depression (hypothermia, ptosis and diarrhea). Behavioural and biochemical changes were also studied in chronic unpredictable mild stress (CUMS). The results show that EEJC (at 2.5 and 5 mg/kg) produce significant antidepressant activity in FST when compared with control, but less potent than imipramine (10 mg/kg). Locomotor activity in open field box showed that EEJC (at 2.5 and 5 mg/kg) did not produce motor stimulation except at 1.25 mg/kg. The antidepressant effect was not significant in TST. EEJC (1.25, 2.5 and 5 mg/kg) significantly antagonized hypothermia and diarrhea induced by reserpine and also, it potentiated yohimbine lethality. The chronic administration of EEJC (1.25 mg/kg) significantly decreased duration of immobility in the TST, EEJC (1.25, 2.5 and 5 mg/kg) significantly increased glutathione levels and EEJC (5 mg/kg) significantly reduced malondialdehyde level i.e. level of lipid peroxidation. In conclusion, this study show that the ethanol extract of Jatropha curcas leaves might possess antidepressant and neuroprotective activity mediated through an interaction with adrenergic, dopaminergic and serotonergic systems, while the neuroprotective effect might be due to its antioxidant property.