Structure elucidation and anti-tumor activity in vivo of a polysaccharide from spores of Ganoderma lucidum (Fr.) Karst

To explore new anti-tumor constituents in the fungi, a water-soluble polysaccharide, WGLP was obtained from spores of Ganoderma lucidum (Fr.) Karst. The average molecular weight of this polysaccharide was estimated to be 1.5 x 10(4) Da. Monosaccharide composition analysis indicated that it was composed solely of glucose. From methylation analysis, H-1 and C-13 NMR spectroscopy, and periodate oxidation and Smith degradation, it could be concluded that WGLP contained beta-D-glucose residue exclusively, with an average repeating unit of hexasaccharide, having a backbone consisting of (1 -> 3)-beta-D-glucopyranosyl residues, to which the side chain consisting of terminal and (1 -> 6)-beta-D-glucopyranosyl residue is attached at position O-6 of the branching residues. Anti-tumor activity assays in vivo showed that WGLP could significantly inhibit the S180 tumor growth in the mice. Furthermore, no drug-related toxic reactions were observed. It was suggested that WGLP might be a potential anti-tumor agent used in the clinic. (C) 2019 Elsevier B.V. All rights reserved.