EMERGING MECHANISMS AND POTENTIAL ANTIDEPRESSANT ACTION OF MEDICINAL PLANTS

Depression is a common heterogeneous, debilitating and life-threatening mood disorder affecting different segments of the community. Several chemical and synthetic medicines as standard are being employed to treat depression and may lead to complete recovery in only 50% of clinically depressed patients but causes many adverse effects. Thus, scientists are increasing their interest in research towards the utility of medicinal plants for antidepressant activity. Several medicinal plants and its derived medicinal products have been reported to exert antidepressant action in different animal models by the combined effect of their phytoconstituents. In the brain, the alteration in level of various endogenous molecules likes noradrenaline (NA), acetylcholine (Ach), serotonin (5-HT), dopamine, glucocorticoid, gamma-aminobutyric acid (GABA), corticotrophin-releasing hormone (CRH) and hippocampal volume are responsible for depression. Therefore, most medicinal plants through synaptic regulation of serotonin, noradrenaline, and dopamine, overcome the altered level of monoamines in the brain and also reinforcing antioxidant defense mechanism, regulate hypothalamic-pituitary-adrenal axis activity and reducing inflammatory mediators. So, herbal medicines are widely used in contrast to allopathic or synthetic medicines globally because of their least side effects and wide therapeutic applications. The present review aims to highlight the medicinal plants and their antidepressant mechanism involved in the treatment of depression by animal model studies.