中文摘要：

研究桑白皮多糖提取工艺并评价其抗氧化活性,以期为其开发应用提供参考依据和理论支撑。采用超声辅助提取桑白皮多糖,设计正交试验对提取条件进行优化,用硫酸苯酚法测定总糖含量,3,5-二硝基水杨酸（DNS）比色法测定还原糖含量,两者之差表示多糖含量。采用1,1-二苯基-2-三硝基苯肼（DPPH）比色法、羟基自由基（·OH）清除法、超氧阴离子（·O-2）清除法研究其抗氧化活性。桑白皮多糖的最佳提取条件为料液比1∶20,超声时间30min,提取温度50℃,提取2次。桑白皮多糖对DPPH和·OH清除作用与质量浓度剂量相关,以维生素C（Vc）作为阳性对照,结果显示桑白皮多糖对DPPH自由基和·OH具有一定的抗氧化活性。发现桑白皮多糖对邻苯三酚自氧化产生的超氧阴离子促luminol发光体系具有增敏作用。进一步研究发现该增敏作用与多糖质量浓度成线性相关。桑白皮多糖具有一定抗氧化性但不及Vc,桑白皮多糖对邻苯三酚自氧化体系的增敏作用具有特异性,该发现具有潜在应用价值。

英文摘要：

To study the extraction process of polysaccharides from Mori Cortex and evaluate their antioxidant activity, so as to provide reference basis and theoretical support for their application. Ultrasonic is chosen as an auxiliary means to extract polysaccharide from Mori Cortex, and the extraction process is optimized by orthogonal experimental design method. The content of total sugar is determined by means of phenol-sulfuric acid method, 3,5-dinitro salicylic acid method is used to reduce sugar, and the difference between these two is the polysaccharide content. Antioxidant activity is determined by DPPH method, hydroxyl free radicals method and the ultra oxygen anion method. It is showed that the best condition for polysaccharide extraction is of 20 times of water adding, 30 rain of ultrasonicing, temperature at 50 ℃, and 2 times of extraction. The scavenging activity on DPPH and ~ OH of Mori Cortex polysaccharides is dependent on concentration. With Vc as a positive control, the polysaccharides show some antioxidant activity on DPPH and OH free radicals. Especially, sensitizing effect of the polysaccharides is found in luminol chemiluminescence system which is caused by superoxide anion produced by the autoxidation of pyrogallol. Further research on the phenomenon found that the sensitizing effect of polysaccharide has linear correlation with the concentration. Polysaccharides of Mori Cortex have some oxidation resistance but not as good as Vc. The sensitizing effect of the polysaccharides on luminol chemiluminescence system shows specificity, which has potential application value.