Fractionation, structural characterization, and immunomodulatory activity of polysaccharide isolated from Ganoderma lucidum / 中草药

ABSTRACT

Objective To extract, separate, and purify polysaccharide from Ganoderma lucidum with alkali from the residue after water extraction, characterize the basic physicochemical properties and structural features in detail, and study the immunomodulatory activity in vitro. Methods The polysaccharide LZJ-015 was isolated and purified from the dry fruiting bodies of G. lucidum by alkaline extraction and ethanol precipitation following Q-Sepharose Fast Flow ion exchange chromatography column. Monosaccharide composition and molecular weight of LZJ-0.15 was analyzed by high performance liquid chromatography (HPLC) with PMP precolumn derivatization and high performance gel permeation chromatography-multiple angle laser (HPGPC-MALLS), respectively. The detailed structure of polysaccharide LZJ-0.15 was characterized by 1H-NMR, 13C-NMR, 1H-1H COSY, and 1H-13C HSQC spectrum. The immunomodulatory activity of G. lucidum polysaccharide was test by RAW264.7 cells phagocytose neutral red experiment. Results The molecular weight, molecular radius, and Mw/Mn of LZJ-0.15 were determined to be 24 700, 46.6 nm, and 1.019, respectively. The monosaccharide composition was confirmed to be mainly composed of glucose (92.3%). LZJ-0.15 was →3) Glc (β1→and→6) Glc (β1→linked glucan indicated by NMR spectrum. Moreover, G. lucidum polysaccharide exhibited good immunomodulatory activity in our study. Conclusion G. lucidum polysaccharide LZJ-0.15 from alkaline extraction showed better immune activity than the polysaccharide extracted from water, which would be potentially developed as an effective immunomodulatory agent.