Comparative study on physicochemical characterization and immunomodulatory activities of neutral and acidic Lycium barbarum polysaccharides

Lycium barbarum polysaccharides (LBPs) are recognized as key bioactive constituents of Lycium barbarum with diverse biological activities. However, current research on LBPs is largely confined to crude extracts, offering limited insight into the structural properties underlying their biological effects. In this study, we separated crude LBP into acidic LBP (ALBP) and neutral LBP (NLBP), which exhibited distinct physicochemical properties. ALBP, consisting of 76.18 % galacturonic acid (GalA), demonstrated crystallinity, thermal stability and gelatinous characteristics. In contrast, NLBP, with only 3.16 % GalA, displayed a more porous structure and superior fluidity. Furthermore, functional analysis revealed that NLBP exhibited enhanced immunoregulatory effects by activating dendritic cells and repolarizing macrophages. In a B16F10 melanoma-bearing C57BL/6 J mice model, NLBP significantly inhibited tumor growth with an inhibition rate of 66.7 % through macrophage repolarization. The findings highlight the distinct biological effects of NLBP and ALBP, providing a theoretical foundation for the refined utilization of LBP.