Purification, characterization, and bioactivities of a polysaccharide from mycelial fermentation of Bjerkandera fumosa

In this work, a novel polysaccharide (named DBFM3) was isolated from mycelia of Bjerkandera fumosa by DEAE-32 and Sepharose CL-6 B column chromatography. High-performance gel permeation chromatography showed that DBFM3 was homogeneous, with an average molecular weight of 1.8 × 105 Da. Structural characteristics of the purified fraction were investigated by high-performance liquid chromatography (HPLC), FT-IR, and NMR. HPLC analysis indicated that DBFM3 was composed of mannose, galacturonic acid, and galactose at molar ratios of 1:18.16:0.702. Spectral analysis suggested that DBFM3 had (1 → 6), (1 → 3,6), (1 → 3) linkages and pyranose conformation. Antioxidant assay in vitro showed that DBFM3 exhibited 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical scavenging activity, and has protective effect against DNA damage and damage to SH-SY5Y cells induced by H2O2. Immunological tests indicated that DBFM3 significantly increased lymphocyte proliferation in vitro. Furthermore, DBFM3 increased the proliferation of lymphocytes in the presence of concanavalin A or lipopolysaccharide as mitogen.