Separation, structure characterization, conformation and immunomodulating effect of a hyperbranched heteroglycan from Radix Astragali

► The major polysaccharide of Radix Astragali was purified and elucidated, by chemical and spectral analysis, to be a hyperbranched heteroglycan. ► Morphology analysis showed that it took random coil feature. ► It exhibited promising immunomodulating effects by stimulating the proliferation of human peripheral blood mononuclear cells and enhancing its interleukin production.