南瓜多糖衍生物的制备及其抗氧化研究

对超声辅助法提取的南瓜粗多糖，进行化学改性得到了硫酸化南瓜多糖和羧甲基南瓜多糖。用邻苯三酚自氧化法检测对超氧阴离子自由基的清除作用，用邻二氮菲-金属铁离子-H2O2体系检测对羟自由基的清除作用。结果表明，南瓜多糖对超氧阴离子自由基无抑制作用，经化学改性后的羧甲基南瓜多糖和硫酸化南瓜多糖对超氧阴离子自由基有明显抑制作用，最大清除率达44％和41．67％。以上3种多糖均能有效清除·OH，随着浓度的增加清除作用加强，最大清除率可达46．49％，22．61％和42．35％0。结果显示，经化学改性后的南瓜多糖有较强的抗氧化作用。

Antioxidant activity of carboxymethylated and sulfated polysaccharides from pumpkin

The antioxidation activity of carboxymethylated and sulfated polysaccharides from pumpkin was investigated. The method for antioxidation reaction system of the pyrogallol was performed to study the scavenging action of pumpkin polysaccharide on superoxide radicals. The phenanthroline Fe^2＋ reaction system was used to measure the scavenging activity of pumpkin polysaccharide on hydroxyl radical. The result showed that the pumpkin polysaccharide was not active against superoxide radicals, and the carboxymethylated and sulfated pumpkin polysaccharides were active against the radicals, the highest inhibition rates were 44% and 41.67% , respectively. The pumpkin polysaccharide and its derivatives had the ability to scavenge hydroxyl radical. Their scavenging actively increased with the increasing of the concentration, the highest inhibition rates were 46. 49% ,22.61% and 42. 35% , respectively. It was demonstrated that the modified pumpkin polysaccharide had excellent antioxidation property performance.