Biochemical characterization of a proteoglycan complex from an edible mushroom Ganoderma lucidum fruiting bodies and its immunoregulatory activity

A fraction, LZ-D-7, was isolated from the fruiting body of the edible mushroom Ganoderma lucidum using a series of chromatographic steps. Biochemical experiments showed that the complex is a proteoglycan and has a carbohydrate percentage of 95.3%, along with a protein percentage of 3.3%. Methylation analysis showed the polysaccharide moiety of LZ-D-7 had a backbone of 1,4-disubsituted-glucopyranosyl and 1,2,6-trisubstituted-glucopyranosyl residues. The branches were mainly composed of 1-substituted-glucopyranosyl residue, which was attached to 1,2,6-trisubstituted-glucopyranosyl residue via 2 or 6 position. Investigation of modulation of LZ-D-7 on BALB/c mouse spleen lymphocytes cells resulted in a three to four-fold increase of MSLs percentage. Analysis of activation and proliferation of MSLs indicated that LZ-D-7 activating most of the activated cells were B cells. The B cells were enlarged, expressed CD71+ and CD25+ on the cell surface.