大黄中多糖的提取工艺及其抗氧化活性的研究

摘要

The extraction technology of polysaccharides from Rhubarb was optimized,and its antioxidant activity was also preliminarily investigated. Rhubarb polysaccharide was extracted from rhubarb using the method of the solvent reflux, to determine the optimum extraction and optimize the condition of extract. Then using ultrasonic-assisted extraction as comparison, the affect to polysaccharide's extraction rate between the two methods were compared. When using the method of solvent reflux, the optimum conditions were as follows:using distilled water as extractive agent, ratio of material and liquid was 1∶30, extract temperature was 90℃, and extract time was 2 h.The extraction rate was up to 15.7%. When using the method of ultrasonic-assisted extraction, the extraction rate was lower compared to the method of solvent reflux, as the ultrasonic temperature was 70℃, ultrasonic time was 30 min, the ratio of material and liquid was 1∶35, and extraction rate could be up to 7.9%. The result of the study on antioxidant showed that:the clearance effect of rhubarb polysaccharide on DPPH was very evident, as the increasing of the concentration, the clearance rate was increasing significantly. The clearance rate between rhubarb polysaccharide and Vc were getting close, when the concentration increased to 0.8mg/mL, as the rhubarb polysaccharide was always less than Vc before. It could provide experimental basis for comprehensive utilization and development for Rhubarb.%优化大黄多糖的提取工艺，并对大黄多糖的抗氧化性进行研究。以大黄为原料，采用溶剂回流法提取大黄中的多糖，确定大黄多糖的最佳提取工艺，对提取条件进行优化。再以超声波辅助提取作为对照，对比两种方法对多糖得率的影响。采用溶剂回流提取时，以蒸馏水作为提取剂，在料液比为1∶30，提取温度为90℃，提取时间为2 h的条件下，大黄多糖的得率最大可达15.7%。而采用超声波辅助提取，多糖得率较溶剂回流的提取方法低，在超声温度为70℃，超声时间为30 min，料液比为1∶35的条件下，多糖得率最大为7.9%。抗氧化性结果研究表明：大黄多糖对DPPH自由基的清除作用较为明显，随着大黄多糖浓度的上升，清除率显著增加。在浓度增加到0.8 mg/mL时大黄多糖与Vc对DPPH的清除率开始接近，之前均小于Vc。为大黄多糖的综合利用开发提供了理论依据。