Structure and bioactivities of a galactose rich extracellular polysaccharide from submergedly cultured Ganoderma lucidum

A galactose rich extracellular polysaccharide (GLP-2), which is composed of galactose, mannose, glucose, arabinose and rhamnose in the molar ratios 103:17:12:10:3, was isolated from the submerged culture broth of a basidiomycete Ganoderma lucidum. Its structure was evaluated with chemical techniques, NMR and IR spectroscopy and ESI-MS experiments and the following structure was suggested: oactivity tests showed that GLP-2 enhanced the T and B lymphocyte proliferation at polysaccharide concentrations of 10 and 50 μg/mL and exhibited lymphocyte activity at concentrations of 100 and 200 μg/mL in vitro. The test in mice also showed that GLP-2 significantly enhanced the T and B lymphocyte proliferation and antibody production and increased the mass of spleen tissue at a dose of 25 or 75 mg/kg, but did not show the same effect at a high dose of 150 or 300 mg/kg. However, GLP-2 did not significantly influence the serum IgG and C-3 levels in mice. GLP-2 also showed a hepatoprotective activity in liver injury mice induced by Bacille Calmette-Guérin and lipopolysaccharide.