Abstract: In this study, purified polysaccharides from the fruits of Psoralea corylifolia L. (PPs) were investigated for their general physicochemical properties, monosaccharide composition, molecular mass, infrared spectroscopic characteristics, nuclear magnetic resonance (1H-NMR and 13C-NMR) characteristics and microstructure together with their effects on the cell viability of RAW264.7 macrophages. The crude polysaccharides, obtained by hot water extraction and ethanol precipitation, were deproteinized by Sevag’s method and then fractionated into two polysaccharides (PPs-1-1 and PPs-2-1) by DEAE-52 with 0.05 mol/L NaCl as the eluent and Sephadex G-100 column chromatography. Both PPs-1-1 and PPs-2-1 were dried into a white flocculent powder, soluble in water but insoluble in ethanol, n-butanol, acetone, chloroform, petroleum ether and other organic solvents. They were negative to Coomassie brilliant blue staining, and reaction with Fehling reagent, ferric chloride and iodine-potassium iodide, and their total sugar contents were (94.35 ± 0.23)% and (95.27 ± 0.42)%, respectively. Both polysaccharides were composed of rhamnose, arabinose, xylose, mannose, glucose and galactose with different molar ratios, and their average molecular masses were 3.98 × 106 and 4.47 × 106 g/mol, respectively. PPs-1-1, showing a three-dimensional laminar structure with a smooth and dense surface, contained α-/β-furanosides. PPs-2-1, having β-pyranosides, exhibited a multilayer lamellar structure with loose and porous surface morphology. PPs-1-1 and PPs-2-1 at concentrations lower than 0.16 and 0.01 μg/mL, respectively could significantly activate RAW264.7 macrophages.

Key words: Psoralea corylifolia L., polysaccharides, purification, structure identification, cell viability