Synergistic Effects of Ginsenoside Rb3 and Rc From Panax notoginseng Leaf on Alleviating Neuroinflammation via PACAP in Depression

Panax notoginseng Leaf (PNL), an edible-medicinal botanical resource, shows potential as functional ingredients for alleviating depression, owing to their unique saponin composition. This study investigates the regulatory effects of PNL-derived saponins on pituitary adenylate cyclase-activating polypeptide (PACAP) and their related antidepressant mechanisms. Our findings demonstrate that PNL supplementation significantly alleviates depressive-like behaviors. Mechanistically, PNL upregulates PACAP expression in the hippocampus and activates the downstream CREB and mTOR signaling pathways, leading to increased expression of synaptic plasticity markers, including BDNF and PSD95, while concurrently inhibiting microglial activation and the production of pro-inflammatory cytokines. Among the major saponins in PNL, ginsenosides Rb3 and Rc were found to synergistically enhance PACAP expression in the cultured PC12 cells. These results underscore the potential of PNL for novel functional food ingredients, highlighting the antidepressant synergism of its naturally occurring ginsenosides (Rb3/Rc), and provide a natural antidepressant strategy.