Ginsenoside RK3 promotes neurogenesis in Alzheimer's disease through activation of the CREB/BDNF pathway

In the ancient book “Shen Nong's Herbal Classic,” Panax ginseng CA Mey was believed to have multiple benefits, including calming nerves, improving cognitive function, and promoting longevity. Ginsenosides are the main active ingredients of ginseng. Ginsenoside RK3 (RK3), a rare ginsenoside extracted from ginseng, displays strong pharmacological potential. Furthermore, its impact on neurogenesis remains insufficiently investigated. This study aims to investigate whether RK3 improves learning and memory by promoting neurogenesis, and to explore the mechanism of RK3 action. The therapeutic effect of RK3 on learning and memory was determined by the Morris water maze (MWM) and novel object recognition test (NORT). The pathogenesis and protective effect of RK3 on primary neurons and animal models were detected by immunofluorescence and western blotting. Protein expression of cAMP response element-binding protein (CREB)-brain-derived neurotrophic factor (BDNF) signaling pathway was detected by western blotting. Our results showed that RK3 treatment significantly improved cognitive function in APPswe/PSEN1dE9 (APP/PS1) mice and C57BL/6 (C57) mice. RK3 promotes neurogenesis and synaptogenesis in the mouse hippocampus. In vitro, RK3 prevents Aβ-induced injury in primary neurons and promotes the proliferation of PC12 as well as the expression of synapse-associated proteins. Mechanically, RK3 plays a positive role in vivo and in vitro through the CREB-BDNF pathway. In conclusion, this study demonstrated that RK3 promotes learning and cognition in APP/PS1 and C57 mice by promoting neurogenesis and synaptogenesis through the CREB-BDNF signaling pathway. Therefore, RK3 is expected to be further developed into a potential drug candidate for the treatment of Alzheimer's disease (AD).