In-Depth Investigation on Potential Mechanism of Forest-Grown Ginseng Alleviating Alzheimer's Disease via UHPLC-MS-Based Metabolomics

Background: Alzheimer's disease is a central nervous system degenerative disease closely related to age with a complex pathogenesis. As a natural medicinal plant, forest-grown ginseng (GSF) contains abundant ginsenosides and offers significant neuroprotective effects. Methods: In this study, we comprehensively investigated the effect of GSF on the cell viability of PC12 cells in an AD model alongside metabolic changes in the serum and brains of mice, combined with an efficacy evaluation of PC12 cells in vitro and UHPLC-MS-based metabolomics in vivo. The goal of this study is to clarify the potential mechanism of GSF in treating AD. Results: The PC12 cell results showed that GSF can promote the proliferation of PC12 cells, reduce the content of IL-8, increase the activity of SOD, and alleviate the inflammation and oxidative stress induced by A beta 25 similar to 35. The immunohistochemical results for the mouse brain tissue also showed that GSF could reduce the inflammatory response of mouse brain tissue by reducing the overexpression of IBa1. AD was alleviated by reducing A beta protein deposition in the mouse brain tissue. An untargeted metabolomics analysis was performed using UHPLC-Q-Exactive MS and principal component analysis (PCA) to identify the differentially expressed metabolites in the serum and brain tissue of AD mice after treatment. Twenty and seventeen different metabolites were identified in the serum and brain tissue, respectively. The pathway enrichment analysis of differential metabolites showed that GSF could treat AD by up-regulating succinic acid semialdehyde, carbamoyl phosphate, Sphingosine 1-phosphate, L-cystathionine, 2-ketobutyric acid, Vanillylmandelic acid, and D-Ribose to regulate sphingomyelin metabolism, the synthesis and metabolism of neurotransmitters and precursors, and energy metabolism. Conclusions: GSF can reduce neuroinflammation and alleviate Alzheimer's disease by regulating the metabolic disorders of amino acids, sphingolipids, unsaturated fatty acids, and arachidonic acid in mice serum and brain tissue metabolites. These results suggest a link between metabolite imbalance and AD, and reveal the basis for the mechanism of ginsenosides in AD treatment.