Amauroderma rugosum Extract Improves Brain Function in d-Galactose-Induced Aging Mouse Models via the Regulatory Effects of Its Polysaccharides on Oxidation, the mTOR-Dependent Pathway, and Gut Microbiota

The pharmacological effects of Amauroderma rugosum (AR), an edible mushroom found mainly in Southeast Asia, are not well studied, particularly its neuroprotective properties. This study investigated the neuroprotective effects of AR aqueous extract (ARW) in a d-galactose-induced accelerated aging mouse model and senescent SH-SY5Y neuronal cells. Behavioral tests (open field, Morris water maze, Y-maze, and rotarod) demonstrated that d-galactose-induced aging mice exhibited impaired cognitive function, memory loss, anxiety, and reduced locomotor ability, all of which were alleviated by ARW treatment. Histological analysis showed that ARW reduced neuropathological lesions in the hippocampus. In SH-SY5Y neuronal cells, ARW and AR polysaccharide extract (ARP) enhanced cell viability and decreased intracellular reactive oxygen species (ROS) levels in a concentration-dependent manner. ARW and ARP also reduced cellular senescence and apoptosis in d-galactose-treated cells. Western blot analysis indicated that ARW and ARP upregulated the phosphorylation of mTOR and increased the expression of antioxidant enzymes, including superoxide dismutase 1 and heme-oxygenase-1. Additionally, ARW altered the gut microbiota, increasing the relative abundance of beneficial bacteria such as Lactobacillus reuteri and decreasing harmful bacteria like Clostridium scindens. These findings suggest that AR exerts neuroprotective effects primarily through its polysaccharides by modulating oxidative stress, activating the mTOR-dependent pathway, and influencing the gut microbiota. Consequently, AR could serve as a potential dietary supplement for the prevention and treatment of neurodegenerative diseases.