Selecting And Structure Analysis Of The Anti-Radiational Polysaccharide In Maize Pollen

Maize pollen is a new resource of Medicinal and Edible food, in which the polysaccharide is a very important function-factor. In this study, we chose corn pollen as our research objective. Polysaccharides were extracted by hot-water from corn pollen and precipitated with 60% ethanol, 80% ethanol and 95% ethanol in turn, respectively noted as PPM-A, PPM-B and PPM-C. The polysaccharide with more powerful anti-radiation activity was screened out through the combination experiments of antioxidant activities in vitro and protecting mice against radiation in vivo. Further, we studied the physical and chemical properties and structure of active polysaccharide. The study will make up for the blanks about the research on the anti-radiation activity of maize pollen. The main conclusions are drawn as follows.Polysaccharides were extracted by hot-water from corn pollen and precipitated with 60% ethanol, 80% ethanol and 95% ethanol in turn. 49.4g PPM-A, 48.0g PPM-B and 168.5g PPM-C were extracted from 4500g pretreated corn pollen. The polysaccharide contents of PPM-A, PPM-B and PPM-C were 62.2%, 49.15%, 36.43% measured by sulfuric acid-phenol method.By establishing the reaction system of hydroxyl radical, superoxide radical and reducing power, we detected antioxidant activity of PPM-A, PPM-B and PPM-C with different doses in vitro. The three kinds of polysaccharide were found to have some reducing power, hydroxyl radical and superoxide radical scavenging activity. The PPM-B is considered to have stronger antioxidant ability in vitro according to comprehensive comparison and analysis of experimental results.The experiments of protecting mice against radiation in vivo show that polysaccharides of maize pollen have some inhibition and restoring functions on oxidative damage, hematopoietic system damage and immune system damage of mice induced byγ-ray. The PPM-A, PPM-B, PPM-C can improve the mice's liver and spleen index, the number of peripheral white blood cells, the organism's SOD and GSH-PX enzyme activity and reduce the organism's accumulation of MDA. The PPM-A is considered to have stronger anti-radiation activity in vivo according to comprehensive comparison and analysis of experimental results.The PPM-A is a water-soluble substance with viscosity-average molecular weight 3.17×105. Chemistry Experiments show that PPM-A contains a reducing polysaccharide, uronic acid, protein and other ingredients. IR spectra proves that the PPM-A is a polysaccharide compounds containing protein, uronic acid,α-andβ-glucose units,β-D-glucopyranosyl. X-ray diffraction analysis confirmed that t- he PPM-A was not able to be crystallized under the experimental conditions. Thermodynamic analysis showed that PPM-A has good thermal stability less than 110℃.