RESUMO
Objective: To extract and separate a polysaccharide from Polygonum multiflorum, characterize its structural features and study its immunomodulatory activity. Methods The polysaccharide from P. multiflorum (PMT) was isolated and purified by water extraction and ethanol precipitation following Q-Sepharose Fast Flow ion exchange chromatography column. Molecular weight of PMT was determined by high performance gel permeation chromatography-multiple angle laser light scattering (HPGPC-MALLS), and monosaccharide composition was analyzed by HPLC with PMP (1-phenyl-3-methyl-5-pyrazolone) pre-column derivatization, respectively. The structure of PMT was characterized by proton nuclear magnetic resonance spectrum (2D-NMR). The immunomodulatory activities were tested by MTT, neutral red colorimetric assay and Griess method. Results: PMT was a kind of α-1,4-glucan, and its molecular mass was 3.96 × 105. PMT promoted the proliferation and phagocytosis of RAW 264.7 cells, and significantly induced the increase of NO production in a dose-dependent manner. Conclusion: The polysaccharide from P. multiflorum is a linear α-1,4-glucan with potent immunomodulatory activity, which would be potentially developed as an effective drug.