玉米秸秆木聚糖的硫酸化修饰及抗氧化活性研究

Study on the synthesis and antioxidant activities of a sulfated cornstalk xylan

以玉米秸秆为原料采用碱提醇沉法提取木聚糖,通过筛选合适的酯化体系(ClSO_(3)H/C_(5)H_(5)N法、C_(5)H_(5)N·SO_(3)/C_(5)H_(5)N法、氨基三磺酸钠法)制备了玉米秸秆木聚糖硫酸酯,产物结构特征经IR、^(13)C NMR确证,进一步考察了其抗氧化活性。通过碱提醇沉法获得木聚糖,经氨基三磺酸钠法酯化体系(反应时间2.5 h,反应温度45℃),所获得的产物硫酸取代度(DS)为1.566。体外抗氧化实验表明,玉米秸秆木聚糖硫酸酯对·OH有较好的清除能力,具有剂量依赖性,并且硫酸酯化可以提高玉米秸秆木聚糖的抗氧化活性。

Cornstalk was used as raw material,from which cornstalk xylan was obtained by alkaline extraction and alcohol precipitation.Then a sulfated cornstalk xylan was synthesized by three sulfating methods(chlorosulfuric acidpyridine method,sulfur trioxide-pyridine method and sodium sulfamate method).The structure of sulfated cornstalk xylan were characterized by IR and ^(13)C NMR,and its antioxidant activity in vitro was further investigated.Structural characterization revealed that sulfate groups were successfully grafted onto cornstalk xylan.The results indicated that,the optimal conditions for sulfating were sodium sulfamate method at a reaction temperature of 45℃for a sulfating time of 2.5 h.The degree of substitution(DS)of the sulfated cornstalk xylan thus obtained was 1.566.The results of in vitro antioxidant activities showed that,sulfated cornstalk xylan had scavenging ability on hydroxyl radicals in a dosedependent manner,and sulfation could improve the antioxidant activity of cornstalk xylan.