Isolation and structure elucidation of polysaccharides from fruiting bodies of mushroom Coriolus versicolor and evaluation of their immunomodulatory effects

Coriolus versicolor is an edible medicinal mushroom in China. Two polysaccharides, named as CVPn and CVPa were separated from the dried fruiting bodies of Coriolus versicolor by water extraction and ethanol precipitation. Their chemical structures were well elucidated with overall consideration of monosaccharide composition, methylation analysis and 1D/2D-NMR spectra data. The bioactivities on RAW 264.7 macrophages cells were evaluated, and further structure-bioactivity relationships were concluded. With molecular weight of 29.7 kDa for CVPn and 50.8 kDa for CVPa, the two isolated polysaccharides were both composed of (l → 4)-β-/(1 → 3)-β-d-glucopyranosyl group as backbone with branches attached at O-6 site. Comparing to CVPn, CVPa with relative high molecular weight and less branches showed significant induction of NO production, obvious augmentation of iNOS and TNF-α mRNA expression level, and phagocytosis on RAW 264.7 cells. These results clarified that CVP polysaccharides with less branches and high molecular weight possessed enhanced immunomodulatory ability, and this finding could be a reference for the utilization of Coriolus versicolor.