Introduction: Kynurenine (KYN) accumulation in periphery induces brain injury, responsible for depression. α‐Asarone is a simple phenylpropanoids that exerts beneficial effects on central nervous system. However, the effect of α‐asarone on periphery is unexplored.Aims: Here, we investigated its protective role against depression from the aspect of KYN metabolism in skeletal muscle.Methods: The antidepressant effects of α‐asarone were evaluated in chronic mild stress (CMS) and muscle‐specific PGC‐1α‐deficient mice. The effects of KYN metabolism were determined in mice and C2C12 myoblasts.Results: α‐Asarone exerted antidepressant effects in CMS and KYN‐challenged mice via modulating KYN metabolism. In myoblasts, α‐asarone regulated PGC‐1α induction via cAMP/CREB signaling and upregulated KYN aminotransferases (KATs) to increase KYN clearance in a manner dependent on PGC‐1α. KAT function is coupled with malate–aspartate shuttle (MAS), while α‐asarone combated oxidative stress to protect MAS and mitochondrial integrity by raising the NAD⁺/NADH ratio, ensuring effective KYN disposal. In support, the antidepressant effect of α‐asarone was diminished by muscle‐specific PGC‐1α deficient mice subjected to KYN challenge.Conclusion: KATs coupled with MAS to clear KYN in muscle. α‐Asarone increased PGC‐1α induction and promoted KYN disposal in muscle, suggesting that protection of mitochondria is a way for pharmacological intervention to depression.

Acori Tatarinowii Rhizome (ATR, the dried rhizome of Acorus tatarinowii Schott), a well‐recognized traditional Chinese herbal medicine, is prescribed to treat neurological disorders. The essential oil is considered as the active fraction of ATR, and the neuroprotection of ATR essential oil (ATEO) is proven, including the protection against oxidative stress. However, the cellular mechanism of ATEO against oxidative stress has not been fully illustrated. In this study, to investigate the cellular mechanism of ATEO, the cytoprotective effect of ATEO against H₂O₂‐induced injury was revealed in PC12 cells. ATEO treatment increased the viability of cells affected by H₂O₂‐mediated injury, inhibited reactive oxygen species (ROS) accumulation, and induced the expression of several antioxidant proteins (SODs, GPx, and UCPs). The cytoprotective effect of ATEO was related to upregulation of peroxisome proliferator‐activated receptor gamma coactivator 1‐alpha (PGC‐1α) expression, which was counteracted by PGC‐1α specific knockdown. Using inhibitor of protein kinase A (PKA), we found that cAMP‐response element binding protein (CREB) activation was involved in ATEO‐induced PGC‐1α expression. Taken together, we suggest that ATEO effectively prevents H₂O₂‐induced cell injury possibly through the activation of CREB/PGC‐1α signaling in PC12 cells. The results provide a molecular insight into the effect of ATEO on cytoprotection against oxidative stress.

HerboChip is an array of different fractions deriving from herbal extracts. This study aimed to identify effective components from Chinese medicine (CM) that interact with nerve growth factor (NGF) as a target using HerboChip. Fifty types of CM that are traditionally used as remedies for emotion imbalance were selected and extracted with 50 % ethanol. Biotinylated-NGF was hybridized with over 300 chips coated with different HPLC-separated fractions from CM extracts and straptavidin-Cy5 was used to identify the NGF-bound fractions. Over 300 chips were screened within a week, and 17 positive hits were identified. The interaction of the identified herbal extracts with NGF was confirmed in cultured PC12 cells. Co-application of NGF and herbal extract interfered with NGF-induced expression of neurofilaments, including NF68 and NF200 in cell cultures. Western blot analysis comparing the intensity of phosphorylated cAMP response element-binding protein (CREB) over total CREB showed NGF-induced CREB phosphorylation was modulated by the identified herbal extracts. Five CM herbs showed activating activities on the NGF response and nine CM herbs showed inhibiting activities. The current result supported the applicability of HerboChip for screening NGF binding components from herbal extracts.