Chain conformation and immunomodulatory activity of a hyperbranched polysaccharide from Cordyceps sinensis

A polysaccharide, named as cordysinan, extracted from natural Cordyceps sinensis, was identified as a hyperbranched heteropolysaccharide from the results of FT-IR, GC-MS, and carbohydrate analysis by carbohydrate gel electrophoresis analysis, as well as the degree of branching of cordysinan was 43.3%. The solution properties of cordysinan were investigated by using size exclusion chromatography coupled with multi-angle laser light scattering and triple detector array, respectively. The molecular weights, the radius of gyration and the intrinsic viscosity of cordysinan were determined as 22.45 +/- 0.26 kDa and 22.37 kDa, 15.4 +/- 2.4 nm and 1.41 mL/g, respectively. By applying the polymer solution theory, the exponent (nu and alpha) values of < S-2 >(1/2)(z) = kM(w)(nu) and [eta] = kM(w)(alpha); were calculated as 0.28 and 0.42, respectively, which firstly revealed that cordysinan existed as a globular shape in 0.9% NaCl aqueous solution. Moreover, the results showed that cordysinan could obviously stimulate macrophages functions. (C) 2014 Elsevier Ltd. All rights reserved.