Ethyl-acetate and aqueous fractions of Moringa oleifera Lam (Moringaceae) leaf extract possess antidepressant activity in mice

Background : Depression is one of most costly psychiatric illnesses all over the world that afflicts roughly 21% of the world population. Moringa oleifera has been used in traditional folk medicine for treating neurologic disorders and plays a key role in memory, mood elevation, response to stimulus such as stress and pleasure which are common in depression. Crude ethanol leaf extract of Moringa oleifera has been scientifically evaluated to have antidepressant activity. Objective : This work evaluated the antidepressant activities of ethyl-acetate and aqueous fractions of Moringa oleifera ethanol leaf extract in mice. Methodology : Ethanol leaf extract of Moringa oleifera was partitioned with ethyl-acetate and water to obtain two fractions. Preliminary phytochemical screening and acute toxicity studies were carried out on both fractions. Antidepressant activity of both fractions at doses of 100, 200 and 400 mg/kg was evaluated using tail suspension (TST), forced swim (FST), and locomotor activity tests in mice. Results : Glycosides, flavonoids, tannins, saponins and terpenoids were detected in both fractions, while the interperitoneal median lethal dose was estimated to be 1,131.4 mg/kg in mice for the two fractions. The ethyl-acetate and aqueous fractions of Moringa oleifera leaf extract significantly ( p <0.05) reduced the immobility time of mice compared to the normal saline treated group in the tail suspension test. In the forced swim test, ethyl-acetate fraction (EF) at the tested doses significantly ( p <0.05) reduced the immobility time compared to the normal saline treated group, while the aqueous fraction (AF) at 200 and 400 mg/kg doses produced a significant ( p <0.05) decrease in the immobility time. In the open field test (locomotor activity test), both fractions did not produce statistically significant difference in the mean number of squares crossed by mice compared to control. Conclusion : This study shows that ethyl-acetate and aqueous fractions of Moringa oleifera ethanol leaf extract possess antidepressant activity without altering motor activity in mice tail suspension and forced swim tests, buttressing the potential of Moringa oleifera in the management of depression in the nearest future. Keywords: Antidepressant, tail suspension, forced swim, Open field, Moringa oleifera .