Structural characterization and immune-enhancing activity of a novel high-molecular-weight polysaccharide from Cordyceps militaris.

A novel homogeneous polysaccharide (CMP-III) was extracted and purified from C. militaris. Structural characterization revealed that CMP-III had an average molecular weight of 4.796 × 104 kDa and consisted of glucose, mannose and galactose with the molar ratio of 8.09:1.00:0.25. The main linkage types of CMP-III consisted of 1 → 4)-α-D-Glc (70.08%), 1 → 4,6)-α-D-Man (9.59%), 1→)-α-D-Man (10.79%) and 1 → 2,6)-α-D-Gal (3.93%) based on methylation and NMR analysis. The immunomodulatory assay indicated that CMP-III significantly promoted macrophage phagocytosis and secretion of NO, TNF-α and IL-6. Further study suggested that macrophage activated by CMP-III involved mitogen-activated protein kinases (MAPKs) and nuclear factor kappa-B (NF-κB) signaling pathways. Overall, these results suggested that CMP-III could be developed as a potent immunomodulatory agent for use in functional foods and dietary supplements.