Isolation, purification and structural analysis of GL-PP-3A, an active polysaccharide peptide from Ganoderma lucidum / 药学学报

ABSTRACT

GL-PP-3A, an active polysaccharide peptide, was isolated and purified from Ganoderma lucidum, and then its structure was analyzed. Crude polysaccharide peptides were extracted from Ganoderma lucidum with hot water, precipitated with ethanol and then dialyzed from Ganoderma lucidum. Subsequently GL-PP-3A was isolated and purified from the crude polysaccharide peptides by fractional precipitation and chromatography of Bio-Gel P-10 column. The repetitive unit of GL-PP-3A was analyzed by high performance gel permeation chromatography (HPGPC), monosaccharide composition and methylation analysis, 1H NMR and 13C NMR. GL-PP-3A is a heteropolysaccharide which is composed mainly of glucose (Glc), and also contains saccharide residues such as rhamnose (Rha), xylose (Xyl), mannose (Man) and galactose (Gal) and 17 kinds of amino acids. Its weight-average molecular weight (Mw) and number-average molecular weight (Mn) were 1.7 x 10(4) and 1.1 x 10(4), respectively, with the ratio of Mw/Mn ( molecular weight distribution) being of 1.49. Its backbone chain is composed of 1,6-linked beta-D-Glcp and 1,3-liked beta-D-Glcp at a ratio of 2:1. Some of 1,6-linked glucose residuals of the backbone chain are substituted at 2-0 or 3-0, and there are 1 to 3 1,6-linked beta-D-Galp or 1,3-linked alpha-D-Manp in the branched chains, the nonreducing ends of which consist mainly of beta-D-Glcp and a few Rha.