Role of BDNF-TrkB signaling in the antidepressant-like actions of loganin, the main active compound of Corni Fructus.

Abstract

Corni Fructus (CF) and some CF-contained prescriptions are commonly used in clinical treatment of depression. This investigation aims to evaluate the main active compound of CF in antidepressant properties and its key target. Firstly, this study established a behavioral despair model and used high-performance liquid chromatography method to evaluate the antidepressant-like effects of water extract, 20%, 50%, and 80% ethanol extracts of CF, and its main active compound. Then, this study created chronic unpredictable mild stress (CUMS) model to assess loganin's antidepressant-like properties, and its target was evaluated by quantitative real-time polymerase chain reaction, Western blot, Immunofluorescence, enzyme-linked immunosorbent assay, and tyrosine receptor kinase B (TrkB) inhibitor. Results showed that the different extracts of CF significantly shortened the immobility time in forced swimming and tail suspension tests. Moreover, loganin alleviated CUMS-induced depression-like behavior, promoted neurotrophy and neurogenesis, and inhibited neuroinflammation. Furthermore, K252a blocked the improvement of loganin on depression-like behavior, and eliminated the enhancement of neurotrophy and neurogenesis and the inhibition of neuroinflammation. Overall, these results indicated that loganin could be used as a major active compound of CF for the antidepressant-like properties and exerted antidepressant-like actions by regulating brain derived neurotrophic factor (BDNF)-TrkB signaling, and TrkB could be used as key target for itsantidepressant-like actions.