Effect of Different Extraction Methods on the Structures and Bioactivities of Polysaccharides from <i>Auricularia auricula</i><i>-</i>judae

This study compared four extraction methods (UHWE, HRE, CWE, and MHWE) for obtaining polysaccharides (AAPs), analyzing their chemical profiles and bioactivities. Chemical characterization included molecular weight distribution, monosaccharide composition, O-acetyl content, and FT-IR, while bioactivities were assessed through radical scavenging assays and macrophage immunomodulation tests. The AAPs produced by HRE have the highest yields with a moderate level of molecular weights across the methods. Although monosaccharide types remained consistent, quantitative variations influenced the structural classification. All AAPs demonstrated strong HO• and DPPH radical scavenging capacities but limited reducing power. Correlation analysis revealed that UHWE-derived AAPs exhibited superior immunostimulatory activity, potentially linked to higher galactose and fucose content. These findings establish method-dependent relationships between extraction techniques and AAP properties, highlighting how physicochemical characteristics influence biological activities. The study underscores the critical role of extraction methodology in determining polysaccharide functionality, while acknowledging limitations in mechanistic interpretation.