Gradient Ethanol Precipitation of Sanghuangporus vaninii Polysaccharides: Physicochemical Properties and Inhibition of Tumor Cell Proliferation

Three polysaccharide fractions (SH-40, SH-60, and SH-80) were sequentially separated from Sanghuangporus vaninii fruiting bodies through graded ethanol precipitation to investigate the influence of molecular weight on their structure, physicochemical properties, and inhibition of tumor cell proliferation. The results revealed that the molecular weights of these three fractions were approximately 5.90 × 105, 4.82 × 105, and 4.13 × 105 Da, respectively; they shared similar functional group profiles, monosaccharide compositions and glycosidic bonds. As the molecular weight decreased, the water holding capacity (WHC) declined, while the water solubility index (WSI) and oil holding capacity (OHC) increased. In tumor cell proliferation inhibition assays, all three fractions inhibited the proliferation of MCF-7, HepG2, A549, and SGC-7901 cells in a concentration-dependent manner and maintained a high cell survival rate (>70%) in normal HUVECs; among them, SH-40 showed the lowest half-maximal inhibitory concentration (IC50) value (1.09–3.89 mg/mL) (p < 0.05). SH-40 displayed the highest biological activity due to its higher molecular weight and characteristic monosaccharide ratio (p < 0.05), suggesting that molecular weight was one of the important factors influencing its function and activity. These findings provided a basis for the hierarchical preparation and differentiated application of polysaccharides isolated from Sanghuangporus vaninii.