Structural characterization and immunomodulatory activity of a novel polysaccharide from Pueraria lobata (Willd.) Ohwi root

A novel polysaccharide with a molecular weight of 12.3 kDa, was isolated from the root of Pueraria lobata (Willd.) Ohwi using cold water extraction method. Methylation analysis, Periodate oxidation, Smith degradation, and nuclear magnetic resonance analysis showed that 1,4-α-D-Glcp and 1,3,6-α-D-Glcp were the main linkage types of this polysaccharide. It exhibited immunomodulatory activity by enhancing the pinocytic and phagocytic capacities and promoting the secretion of nitric oxide, interleukin (IL)-6, and tumor necrosis factor alpha by RAW 264.7 cells. The beta glucan receptor, scavenger receptor I, and toll-like receptor 4 were identified as the main receptors of the polysaccharide on the membrane of RAW 264.7 cells. These results suggested that this polysaccharide is a candidate functional food supplement for hypoimmune populations.