Astragalus polysaccharides (APS) are the principal bioactive constituents of Huangqi (Astragali Radix), exhibiting diverse pharmacological activities. However, their clinical application is limited by challenges including high molecular weight, low solubility, and consequently poor bioavailability. Selenization modification has emerged as an effective strategy to improve the physicochemical properties and biological functions of APS, leading to the formation of selenized APS (Se-APS) and APS-selenium nanoparticles (APS-SeNPs). This review systematically summarizes the preparation methods, structural characteristics, biological activities, and structure-activity relationships of selenium-containing APS derivatives, and discusses their application prospects. Primary preparation techniques include biological transformation and chemical synthesis approaches. Following selenization, the resulting products demonstrate significantly improved solubility, stability, and bioavailability, and can form uniformly sized nanoparticles. Research indicates that selenium-containing APS derivatives exhibit superior pharmacological efficacy compared to native APS, including enhanced antioxidant, immunomodulatory, antitumor, and hepatoprotective activities. Furthermore, APS-SeNPs can serve as effective drug delivery carriers and show synergistic effects when combined with other bioactive compounds. Structure-activity relationship studies suggest that their bioactivity is closely associated with selenium content, molecular weight, and nanostructural attributes. Nevertheless, several challenges remain in this field, such as insufficient characterization of selenization sites and a lack of systematic toxicological evaluation. Future research should focus on optimizing preparation processes, strengthening safety assessments, and promoting clinical translation to advance their applications in the pharmaceutical and functional food industries.

Astragalus polysaccharides  /  selenium polysaccharides  /  selenium nanoparticles  /  bioactivity  /  structure-activity relationship  /  antitumor  /  immune modulation  /  hepatoprotection