Study on macrophage activation and structural characteristics of purified polysaccharides from the liquid culture broth of Hericium erinaceus

Recently, a number of bioactive molecules, including antitumor agents, have been identified in various higher basidiomycetes mushrooms. Polysaccharides are the best known and most potent mushroom derived substances that display immuno-pharmacological properties. In this study, the water soluble crude polysaccharide HEB-P, which was obtained from the liquid culture broth of Hericium erinaceus by ethanol precipitation, was fractionated by DEAE cellulose and Sepharose CL-6B column chromatography. This fractionation process resulted in two polysaccharide fractions that were termed HEB-NP Fr I and HEB-AP Fr I. Of the fractions, HEB-AP Fr I was able to upregulate the functional events mediated by activated macrophages, such as production of nitric oxide (NO) and expression of cytokines (IL-1β and TNF-α). Its structural characteristics were investigated by a combination of chemical and instrumental analyses, including methylation, reductive cleavage, acetylation, Fourier transform infrared spectroscopy (FT-IR), and gas chromatography–mass spectrometry (GC–MS). Results indicate that HEB-AP Fr I was a low molecular mass polysaccharide with a laminarin-like triple helix conformation of the β-1,3-branched-β-1,2-mannan.