Valeriana fauriei Exerts Antidepressant-Like Effects Through Anti-inflammatory and Antioxidant Activities by Inhibiting Brain-Derived Neurotrophic Factor Associated with Chronic Restraint Stress

Although depression is the most common psychiatric disorder, its pharmacological properties are not well known yet. It has been reported that Valeriana fauriei (VF) extract is beneficial for several neurological diseases. However, little information is available regarding its antidepressant activity. Therefore, the objective of this study was to determine antidepressant activity of VF and the underlying mechanism involved in its effect on chronic restraint stress (CRS)-induced depression using a mouse model. Oral treatment of VF extract for 14 days significantly ameliorated depression-like behavior (immobility time) in forced swimming and tail suspension tests following CRS induction, in accordance with decreased levels of serum corticosterone. VF extract ameliorated c-Fos expression, microglial activation, phosphorylated p38 expression, and inflammatory response (protein expression levels of cyclooxygenase-2 and inducible nitric oxide) in the prefrontal cortex, hippocampus, and amygdala of mice after CRS induction. However, VF extract enhanced the stimulation of nuclear factor erythroid 2-related factor 2 pathways, in accordance with upregulation in protein expression of brain-derived neurotrophic factor (BDNF). Collectively, our findings demonstrate that VF extract has antidepressant-like activity against CRS-induced depression through its anti-inflammatory and antioxidant effects by inhibiting BDNF expression. Further studies are warranted to investigate VF extract's fraction and components to develop possible antidepressants.