The Saccharide Mapping and Biological Activity Analysis of Auricularia heimuer Polysaccharides from Different Origins In Vitro

Auricularia heimuer (A. heimuer) polysaccharides (AHPs) are the main bioactive components of edible and therapeutic fungi. AHPs have considerable potential for use in healthy meals and supplements; however, because of their large molecular weight and structural complexity, quality control remains difficult. A total of 32 A. heimuer samples were collected from various geographic locations. High-performance liquid chromatography (HPLC), high-performance gel permeation chromatography (HPGPC-ELSD), Fourier transform infrared spectroscopy (FT-IR), and high-performance thin-layer chromatography (HPTLC) were used to characterize the physicochemical properties and saccharide profiles of AHPs. The findings showed that Man and Glc constituted the majority of AHPs, with molecular weights varying between 3.6 and 6820 kDa. All samples demonstrated in vitro antioxidant, lipid-lowering, and hypoglycemic properties in a concentration-dependent manner. Critical structure–activity relationships were identified through correlation analysis: uronic acid content (expressed as galacturonic acid equivalents), Glc, and Man were linked to antioxidant activity, while Man, Xyl, specific molecular weight ranges, and distinctive FT-IR absorption peaks (1731, 1376, 1245, and 1656 cm−1) were linked to hypoglycemic and lipid-lowering effects. This research provides support for quality grading, functional development, and industrial standardization of A. heimuer production areas.