Studies on structural properties and immune-enhancing activities of glycomannans from Schizophyllum commune

Polysaccharides were extracted from Schizophyllum commune (a common mushroom) and their structural and immune-enhancing properties were investigated. Crude and fractions (F-1 and F-2) were composed of sugars (50.3-82.8%), proteins (1.46-20.1%), and sulfates (1.33-7.01%). Monosaccharide compositions of Cr and F-1 were mainly composed of glucose (75.5% and 88.2%) with small amounts of mannose, galactose and xylose whereas the F-2 was mainly composed of manose (55.2%) with minor amounts of galactose, glucose, and xylose. Their immune-enhancing activities were tested using RAW264.7 cells. Proliferation activity of RAW264.7 cells was over 100% after treatment with these polysaccharides. In addition, RAW264.7 cells produced large amounts of nitric oxide and various cytokines by up-regulating mRNA expression levels and the activation of nuclear factor-kappa (NF-kappa B) and mitogen-activated protein kinase (MAPK) after treatment with these polysaccharides. In addition, RAW264.7 cells were activated mainly through CR-3 and TLR-4 receptors. The backbone of F-2 with excellent immune-enhancing activity was mainly linked by (1 -> 3)-linked-mannopyranosyl and (1 -> 2,3)-linked-mannopyranosyl residues.