LAUSR

A water-soluble β-D-glucan was obtained from wild Cordyceps sinensis (C. sinensis) by alkali solution and ethanol precipitation. The structure characteristics were determined using high performance anion exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD), methylation combined with gas chromatography-mass spectrometry (GC-MS), and 1D/2D NMR spectroscopy. Results showed that the β-D-glucan had a structure of every seven (1→3)-β-D-Glcp backbone residues with two (1→6)-β-D-Glcp branches. Additionally, conformation properties in different solvents were investigated by static light scattering (SLS), dynamic light scattering (DLS), and HPSEC with multiple detectors. It was found that the β-D-glucan in 0.5 M NaOH had a narrow unimodal distribution of hydrodynamic radius displaying a spherical coil conformation, whereas it formed severe aggregation in dimethyl sulfoxide (DMSO). In 0.1 M NaNO3, the β-D-glucan mainly existed as a rod-like conformation corresponding to a helical structure together with a small aggregates (10%). This work added more information to the understanding of C. sinensis polysaccharides.