Edible mushroom polysaccharides: Structural characteristics, chemical modification strategies, and structure-activity relationship: A review

Abstract

Edible fungal polysaccharides (EFPs) are emerging bioactive macromolecules, with 4545 articles published from 2014 to 2024 and over 118,000 citations. However, their structure–activity relationship (SAR) remains inadequately defined, and the effects of extraction and chemical modification require systematic evaluation. This review summarizes the structural features of EFPs—including α−/β-glucans, heteroglucans, galactans, and mannans—and explores how molecular weight (1.27–5420 kDa), monosaccharide composition, glycosidic linkage patterns, branching, and spatial conformation influence bioactivity. β-(1 → 3)-glucans with β-(1 → 6) branches and triple-helix conformations show strong immunomodulatory effects, while low-molecular-weight fractions (<50 kDa) enriched in uronic acids exhibit enhanced antioxidant activity. Medium-weight polysaccharides (100–500 kDa) act via dectin-1 and Toll-like receptors. Chemical modifications—such as sulfation (DS 1.5–2.0), acetylation, carboxymethylation, selenylation, and phosphorylation—further enhance bioactivities. For example, selenylated EFPs improved zeta potential by 69.12 % and exhibited dose-dependent antitumor effects, while phosphorylated derivatives showed enhanced anti-inflammatory activity. The review highlights critical challenges in extraction standardization and quality control. Integration of advanced analytical techniques (e.g., HPSEC-MALLS, 2D-NMR, AFM) enables atomic-level characterization. Future directions include site-specific modification, machine learning-driven SAR prediction, and sustainable design strategies. This work provides a mechanistic foundation for the rational development of EFP-based therapeutics targeting immunity, metabolism, and gut microbiota.