Extraction,Purification and Content Determination of Polysaccharides in Aloe vera L. var chinensis

[Objective] To optimize the extraction technology of polysaccharides from Aloe vera L.var chinensis,compare several purification methods and establish a method for determining the content of polysaccharides.[Method] With the yield and content of polysaccharides as the evaluation criteria,the extraction process of polysaccharides was optimized by orthogonal experiment.Three polysaccharides purification methods,including dialysis,macroporous resin AB-8 absorption and activated carbon absorption,were compared.The polysaccharides content was detected colorimetrically by the phenol-sulfuric acid method after the conversion coefficient of Aloe vera L.var chinensis polysaccharides to glucose was obtained.[Result] The optimal process conditions for extraction were obtained by orthogonal experiment and the optimal parameters were as follows: the solid-liquid ratio of 1∶ 10 g/ml,twice of extraction,and 3 h of extraction time.The contents of polysaccharide purified by the three methods were shown as dialysis macroporous resin AB-8 activated carbon;while the yield of polysaccharides was shown as activated carbon dialysis macroporous resin AB-8;the conversion coefficient of polysaccharide to glucose was determined to be 1.32,the average recovery was 98.4% with a relative standard deviation of 2.36%.[Conclusion] The optimized extraction process is economical,simple,stable and practical,the dialysis method is simple,rapid and cheap to be used for purifying the polysaccharides.The phenol-sulfuric acid method is simple and accurate with good reproducibility.