RESUMO
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．
RESUMO
Comprehensive utilization of rapeseed and rapeseed meal has been increasingly emphasized, and contaminative problems of heavy metal have been attracting great attention, so it is of quite important significance to determine the contents of Pb and Cd. An effective method was developed for the rapid determination of Pb and Cd in rapeseed and rapeseed meal. Digestive dissolvent, time and pressure were discussed for sample preparation by microwave digestion technique, and the optimum condition of determination by GFAAS was studied. The determination limits were 2.172 and 0.243 microg x L(-1), and the linear arranges were 0-100 microg x L(-1) and 0-8 microg x L(-1) for Pb and Cd, respectively. The recoveries were from 80.8% to 110.7%. The RSD of determination was lower than 5.3%. The method offers traits of low detection limit, high sensitivity, speediness and exactness, and was applied to the determination of Pb and Cd in samples with satisfactory results.
