Structural characterization, controlled enzymatic hydrolysis and immunomodulatory activities of three ginseng...

This study systematically investigated the structure-immunomodulatory activity relationship of three ginseng polysaccharides (GPs). GP40015-1 was identified as a high-molecular-weight neutral glucan, whereas GP40025-1 and GP40030-1 were acidic heteropolysaccharides with distinct uronic acid contents and branching patterns. Controlled enzymatic hydrolysis combined with LC-ESI-MS/MS was employed to decipher their specific oligosaccharide sequences. Immunomodulatory assessment on RAW264.7 macrophages demonstrated that all three GPs promoted cell proliferation and phagocytic activity in a dose-dependent manner. GP40025-1 exhibited the strongest bioactivity, enhancing proliferation by 158.4% and phagocytosis to 246.6% at 100 μg/mL. Its superior immunomodulatory potential was attributed to a lower molecular weight, a unique β-linked backbone with →1)-α-Glc-(3→ and →1)-β-GlcA-(4→ branching motifs, and an optimal uronic acid content. These findings provide crucial insights into the structure-activity relationship of GPs and underscore the potential of GP40025-1 as a functional food ingredient with natural immunomodulatory properties.