南瓜硒多糖的制备表征及活性分析

Preparation,Characterization and Activity Analysis of Selenium-Containing Pumpkin Polysaccharide

对南瓜多糖进行硒化修饰,并对南瓜硒多糖的体外抗氧化和抑制人乳腺癌细胞MDA-MB-231生长等活性进行研究。以提取、分离、纯化的南瓜多糖为前体物,用Na_2SeO_3硒化修饰制备南瓜硒多糖,并用紫外光谱、红外光谱、原子荧光光谱、热重分析对产物结构进行表征,采用邻苯三酚自氧化法、水杨酸法、四甲基偶氮唑蓝比色法测定其清除超氧阴离子自由基(O-2^-·)、羟自由基(·OH)的能力以及对人乳腺癌细胞MDA-MB-231生长的抑制作用。结果表明:制备产物结构中含有Se=O键和Se—C键,即实现了南瓜多糖的硒化。南瓜硒多糖对O_2^-·、·OH的清除作用显著强于南瓜多糖,与样品量呈正相关;南瓜硒多糖对人乳腺癌细胞MDA-MB-231生长有抑制作用,比南瓜多糖具有更好的抑制效果。

Objective： To investigate selenium modification of pumpkin polysaccharide and to evaluate the in vitroantioxidant activity and antitumor effect against human breast cancer MDA-MB-231 cells of the modified polysaccharide.Methods： Pumpkin polysaccharide was prepared and purified and it was modified by reaction with Na2SeO3 to obtainselenium-containing polysaccharide. Furthermore, the structure of the modified polysaccharide was characterized throughUV, IR, atomic fluorescence spectroscopies and thermogravimetric analysis. Finally, its scavenging effect on O2-· and·OH as well as growth inhibitory effect on breast cancer cells were tested by using pyrogallol autoxidation, salicylicacid method and methyl thiazolyl tetrazolium colorimetric assay. Results： Se=O and Se–C bonds were observed in thestructure of the target product, thus successfully achieving the selenium modification of pumpkin polysaccharide. Theselenium-containing pumpkin polysaccharide had significantly stronger scavenging effects on O2-· and ·OH than ordinarypumpkin polysaccharide, which were concentration-dependent. Meanwhile, the modified polysaccharide also inhibited thegrowth of human breast cancer cells in a dose-dependent manner more significantly than did the unmodified one.