Structural characterization and immunomodulatory activity of a glucan from Radix Codonopsis

A glucan named as CPC was obtained from the roots of Codonopsis pilosula and its structure was determined by HPGPC, IR, GC-MS, and NMR. HPGPC showed that CPC was a homogeneous polysaccharide and exhibited a molecular weight (Mp) of 1698 Da according to the equation of standard molecular weight (lg Mp = -0.1869 tR + 9.7386). The results from NMR and GC-MS demonstrated that the main linkages in CPC were 1-linked beta-Dglucose, 1,4-linked alpha-D-glucose, and 1,4,6-linked alpha-D-glucose in the molar ratio of 1.0:3.8:1.0, which indicated that the structure of CPC exhibited the backbone of 1,4-linked alpha-D-glucose and the branched chains of 1,6-linked beta-D-glucose. The immunomodulatory activity indicated that CPC showed the significant induction on the productions of NO, ROS, iNOS, TNF-alpha, IL-6, IL-1 beta and IL-10 and the mRNA expressions of iNOS, TNF-alpha, IL-6, IL-1 beta and IL-10 in RAW 246.7 cells. These data suggested that CPC was potential to human health by regulating immunity.