Preparation, Characterization, and Bioactivities of Polysaccharide-Nano-Selenium and Selenized Polysaccharides from .

polysaccharide-nano-selenium (ASPS-SENPS) and selenized polysaccharides (Se-ASPS) were synthesized, and their characterization and biological properties were compared. The acid extraction method was used to extract the polysaccharides of , followed by decolorization using the hydrogen peroxide method and deproteinization based on the Sevage method, and the purification of polysaccharides (ASPS) was carried out using the cellulose DEAE-52 ion column layer analysis method. An polysaccharide-nano-selenium complex was synthesized by a chemical reduction method using ASPS as dispersants. The selenization of polysaccharides from was carried out using the HNO-NaSeO method. The chemical compositions, scanning electron microscopy images, infrared spectra, and antioxidant properties of ASPS-SENPS and Se-ASPS were studied, and they were also subjected to thermogravimetric analysis. The results indicated that the optimal conditions for the synthesis of ASPS-SENPS include the following: when ASPS accounts for 10%, the ratio of ascorbic acid and sodium selenium should be 4:1, the response time should be 4 h, and the reaction temperature should be 50 °C. The most favorable conditions for the synthesis of Se-ASPS were as follows: m (NaSeO):m (ASPS) = 4:5, response temperature = 50 °C, and response time = 11.0 h. In the in vitro antioxidant assay, when the mass concentration of Se-ASPS and ASPS-SENPS was 5 mg/mL, the removal rates for DPPH free radicals were 88.44 ± 2.83% and 98.89 ± 3.57%, respectively, and the removal rates for ABTS free radicals were 90.11 ± 3.43% and 98.99 ± 1.73%, respectively, stronger than those for ASPS. The current study compares the physiological and bioactivity effects of ASPS-SENPS and Se-ASPS, providing a basis for future studies on polysaccharides.