Structural analysis and antioxidation activity of bupleurum polysaccharide

Polysaccharide SAP3 was extracted and isolated from bupleurum by ultrasonic-assisted extraction.The relative molecular weight was determined by high performance liquid chromatography.Its chemical structure was analyzed by infrared spectrometry(FTIR) and atomic force microscopy(AFM).Experimental results showed that the molecular weight of SAP3 was 3.3×105.FTIR showed there are characteristic absorption peaks on polysaccharide SAP3 and its monosaccharide residues existed in the forms of pyran rings.AFM revealed that bupleurum polysaccharide had a multi-branched structure and ring structure in linkages of adjacent monosaccharides.Their scavenging actively increased with the increasing of the concentration from 0.2 to 1.2 mg/mL,the highest inhibition rate was 45.2%.