Abstract: Ophiopogon japonicus polysaccharide was ultrasonically extracted.It was separated and purified by DEAE-52 cellulose column to afford the polysaccharide POJ-U1b.The purity of POJ-U1b was determined by Sephadex G-150 gel column.The result showed that POJ-U1b was homogeneous.The structure of POJ-U1b was determined by gas chromatography,infrared spectrometry andnuclear magnetic resonance,and the surface morphology of POJ-U1b at different concentrations was observed by atomic force microscopy (AFM).The results showed that POJ-U1b was glucan composed by glucose.The infrared spectrum suggested that there were characteristic absorption bands of polysaccharide in POJU1b,and its monosaccharide residues existed in the forms of pyran and furan rings.POJ-U1b was mainly composed of →6)-α-D-Glcp(1→ linkage.AFM revealed that POJ-U1b had a multi-branched chemical structure in linkages of adjacent monosaccharides,ringed and branched structure was derived from link of polysaccharide chains.With the increasing of concentration,POJ-U1b presented chain and flakiness conglutinate structure,which was related to van der Waals interaction and hydrogen bond of polysaccharide chains.

Key words: Ophiopogon japonicus polysaccharide, structure, atomic force microscopy