Structural Characterization And Immunomodulatory Activity Of A New Polysaccharide Isolated From The Radix Of Platycodon Grandiflorum

In this study, a novel polysaccharide fraction (PGPIV-1-a) was isolated from Platycodon grandiflorum through the combination of DEAE-52 and Sephadex G-100 chromatography. PGPIV-1-a was a neutral heteropolysaccharide with an average molecular weight of about 6462 Da. PGPIV-1-a was composed of glucose, arabinose and mannose in the relative molar ratio of 64.79%, 31.16% and 4.05%. The main linkage types in PGPIV-1-a consisted of -> 6)-beta-Glcp-(1 -> and -> 5)-alpha-L-Ara-(1 ->. Bioactivity assay results showed that PGPIV-1-a significantly stimulated the proliferation of RAW264.7 cells and enhanced their phagocytic capacity in a dose-dependent manner. In addition, treatment with higher dosage of PGPIV-1-a (800 mu g mL(-1)) remarkably induced the secretion of NO, TNF-alpha and IL-6. This study provides a theoretical basis for further systematic investigation and utilisation of Platycodon grandiflorum polysaccharides.