Evaluation of the antidepressant activity of Moringa oleifera alone and in combination with fluoxetine

BACKGROUND The prevalence of mental depression has increased in recent years, and has become a serious health problem in most countries of the world, including India. Due to the high cost of antidepressant synthetic drugs and their accompanying side effects, the discovery of safer antidepressant herbal remedies is on the rise. Moringa oleifera (MO) (drumstick) has been used in traditional folk medicine, and in Ayurveda, it is considered as a valuable remedy for treating nervous system disorders as well as memory enhancing agent. OBJECTIVE The present study was designed to evaluate the acute and chronic behavioral and antidepressant effects of alcoholic extracts of MO leaves in standardized mouse models of depression. MATERIALS AND METHODS Alcoholic extracts of MO (MOE) leaves were prepared, and phytoconstituents were determined using appropriate chemical analytical methods. Following preliminary dose-finding toxicity studies, the biological activity of MOE was tested in Swiss albino mice. Animals were divided into six groups: Groups 1 and 2 served as vehicle control and fluoxetine (20 mg/kg) standard control, respectively. Groups 3 and 4 served as treatment groups and were orally administered ethanolic MOE at doses of 100 mg/kg and 200 mg/kg, respectively. Groups 5 and 6, respectively, received combination doses of MOE 100 mg/kg + 10 mg fluoxetine, and MOE 200 mg/kg + 10 mg/kg fluoxetine. Following acute and 14 days chronic treatments, all animals were tested using behavioral models of depression, such as forced swim test (FST), tail suspension test (TST), and locomotor activity test (LAT). RESULTS Significant changes in all tested activities (FST, TST, LAT) of chronically dosed mice were observed, especially in animals given simultaneously combined doses of 200 mg/kg/day MOE + 10 mg/kg/day fluoxetine for 14 days. The antidepressant effect of MOE may have been invoked through the noradrenergic-serotonergic neurotransmission pathway, which is the hallmark of selective serotonin reuptake inhibitors (SSRI) class of drugs. CONCLUSION The results obtained in this study suggest that combined administration of MOE with low doses of fluoxetine or other SSRI drugs seems to have promising potential.