ABSTRACT
Objective:To isolate and purify a polysaccharide CALB-2 fraction from Aurantii Fructus，and analyze its basic chemical structure, morphological characteristics and bioactivity. Method:A refined CALB-2 was obtained from Aurantii Fructus by hot water extraction，then separated and purified by ion exchange resin，ion exchange agarose gel and propylene dextran gel to obtain homogeneous polysaccharide CALB-2. The molecular mass of CALB-2 was determined by high performance liquid chromatography （HPLC）. Monosaccharide composition analysis of CALB-2 was conducted by methylation analysis and Smith degradation. Structural analysis and morphological characterization were conducted by infrared scanning （IR） and scanning electron microscopy （SEM） analysis. Antioxidant activity of CALB-2 was studied by using H2O2-induced cardiomyocyte oxidative damage model. Result:CALB-2 was a homogeneous polysaccharide and the molecular weight of CALB-2 was estimated to be 3.57×107 Da，which was proved to be a kind of highly branched acidic polysaccharides in IR analysis, methylation analysis and Smith degradation, mainly present in form of 1→3，4 bonds. Through SEM observations，we indicated that the molecular morphology of CALB-2 was amorphous solid. The in vitro activity test showed that CALB-2 had obvious protective effects on injury of H9c2 myocardial cells induced by H2O2. Conclusion:CALB-2 is a kind of homogeneous polysaccharide extracted from Aurantii Fructus， with an anti-cardiomyocyte oxidative damage effect, laying a theoretical foundation for further study of Aurantii Fructus polysaccharides．