苦丁茶冬青粗多糖的分离表征及其抗氧化活性研究

Characterization and Antioxidant Activities of Crude Polysaccharides Isolated from Ilex kudingcha C.J. Tseng

水提醇沉法分离制备苦丁茶冬青粗多糖样品,对其进行初步分离表征(包括总糖、糖醛酸、蛋白质、氨基酸含量和红外光谱分析)和体外抗氧化活性(清除DPPH·自由基、·OH自由基清除能力和还原能力)研究。结果表明,苦丁茶冬青粗多糖中总糖含量为30.67%、糖醛酸含量为12.72%、蛋白质含量为9.35%;含有16种氨基酸成分,总含量为7.72%,其中含有7种人体必需氨基酸,占氨基酸总量的40.41%;红外光谱显示该粗多糖样品中含有α-吡喃糖环结构;此外,苦丁茶冬青粗多糖具有较强的体外抗氧化活性,且其抗氧化活性与多糖浓度之间存在良好的量效关系。

Po lysaccharides of Ilex kudingcha C.J. Tseng were obtained by hot water extraction and alcohol sedimentation. The physico-chemical（ total sugar, uronic acid and protein） and antioxidant capacity（ DPPH radical scavenging activity, hydroxyl radical scavenging activity and reducing power） of polysaccharides isolated from Ilex kudingcha C.J. Tseng. Polysaccharides were isolated sequentially using the Sevag method, ethanol grade precipitation and dried in a lab scale vacuum freeze dryer. The results indicated that the total sugar, uronic acid and protein contents of polysaccharides isolated from Ilex kudingcha C.J. Tseng were of 30.67%, 12.72% and9.35%, respectively. The polysaccharides also contained 16 general amino acids（7.72%） with 7 essential amino acids. In IR spectra, characteristic absorptions range from 855 to 810 cm-1were observed, indicating the α-configuration of the sugar units. The polysaccharides also exhibited strong scavenging activities on DPPH free radicals, hydroxyl radicals（·OH） and reducing-antioxidant power, and the antioxidant activity was significantly correlated with its concentration.