Antidepressant-like effects of ginsenoside Rg3 in mice via activation of the hippocampal BDNF signaling cascade

Current antidepressants are clinically effective only after several weeks of administration. Ginsenoside Rg3 is one component of ginsenosides, with a similar chemical structure to ginsenoside Rg1. Here, we investigated the antidepressant effects of Rg3 in mouse models of depression. The antidepressant actions of Rg3 were first examined in the forced swim test (FST) and tail suspension test (TST), and then assessed in the chronic social defeat stress (CSDS) model of depression. The changes in the hippocampal brain-derived neurotrophic factor (BDNF) signaling pathway after CSDS and Rg3 treatment were investigated. A tryptophan hydroxylase inhibitor and a BDNF signaling inhibitor were also used to determine the pharmacological mechanisms of Rg3. It was found that Rg3 produced antidepressant effects in the FST and TST without affecting locomotor activity. Rg3 also prevented the CSDS-induced depressive-like symptoms. Moreover, Rg3 fully restored the CSDS-induced decrease in the hippocampal BDNF signaling pathway, and use of the BDNF signaling inhibitor blocked the antidepressant effects of Rg3. In conclusion, ginsenoside Rg3 has antidepressant effects via promotion of the hippocampal BDNF signaling pathway.