Structure feature and antitumor activity of a novel polysaccharide isolated from Lactarius deliciosus Gray

A novel heteropolysaccharide was isolated from the fruiting bodies of Lactarius deliciosus Gray through DEAE-cellulose column and Sephadex G-100 column. The L. deliciosus Gray polysaccharide (LDG-A) had a molecular weight of 1.1×10(4) Da and was mainly composed of L-mannose and D-xylose (L-Man and D-Xyl) which ratio was 3:1. As a precondition to understand the bioactivity, structural feature of L. deliciosus Gray polysaccharide (LDG-A) were investigated by a combination of total hydrolysis, methylation analysis, gas chromatography-mass spectrometry (GC-MS), scanning electron microscope (SEM), infrared (IR) spectra, nuclear magnetic resonance (NMR) spectroscopy and dynamical analysis of the atomic force microscope (AFM) studies. The results indicated that L. deliciosus Gray polysaccharide (LDG-A) had a backbone of 1,6-disubstituted-α-L-mannopyranose which branched at O-2 and the branches were mainly composed of a →3)-α-D-xylopyranose residue. LDG-A exhibited significant anti-tumor activates in vivo. L. deliciosus Gray may be one ideal sources of antitumor development.