Optimization of the preparation of Gastrodia elata polysaccharide and investigation of their immunostimulatory activity in mice.

This study employed ultrasound-assisted enzymatic extraction combined with response surface optimization to determine the optimal extraction parameters, achieving a polysaccharide yield of 21.73 %. Kinetic analysis based on Fick's second law revealed that the GP extraction procedure is a non-spontaneous, endothermic reaction and elucidated its mass transfer kinetics. GP is a furan-type polysaccharide formed by D-glucose units linked via α-glycosidic bonds. It is likely to retain a triple-helix structure, presenting as a smooth, layered, amorphous complex with good in vitro antioxidant capacity. A preliminary analysis was conducted on the regulatory effects of GP following selenization (GP-SE) on spleen factors and the gut microbiota. In addition to inhibiting pro-inflammatory factors and alleviating oxidative damage to the body, GP-SE can increase the abundance and diversity of the microbiota, modulate the growth of different microbial groups, and its functional effects are largely consistent with metabolic adaptation. This study provides a theoretical proposal for the functionalized production and process optimization of Gastrodia elata polysaccharides.