Medicinal Plants Effective on Serotonin Level: A Systematic Review

In recent years, the prevalence of depression and mood disorders has been on the rise. With regards to increased popularity of traditional medicine and medicinal plants, we conducted this review to identify and study the action mechanisms of the medicinal plants that are effective on serotonin, as one of the neurotransmitters of happiness and mood, and depression symptoms. To conduct this systematic review, the key words of interest were used to retrieve articles from the Information Sciences Institute (ISI) and the PubMed. The articles, published between 2010 and 2017, about the medicinal plants’ and their products’ potential effects on serotonin and brain serotonergic system were analyzed. Plants and their derivatives may not only exert therapeutic effects on mild depression but also exhibit suitable therapeutic response in treating severe disorders such as major depressive disorder (MDD) to improve mood conditions and eliminate depressed mood through affecting the serotonergic system. Plants and their compounds affect serotonergic system function through anti-inflammatory mechanisms, inhibiting noradrenaline and serotonin reuptake, inhibiting monoamine oxidase (MAO), and increasing expression of serotonin transporter (5-HTT) and hepatic tryptophan 2, 3-dioxygenase. They can therefore be used as options for discovering new drugs effective on happiness and depression.