Effect of Ultrafiltration on Total Sugar Content and Protein Content of Angelica Sinensis Polysaccharide Fractions

Objective To explore the feasibility of isolating Angelica sinensis polysaccharide fractions by ultrafiltration and the effect of ultrafiltration on total sugar content and protein content of these fractions.Methods The fresh plant DangGui from Min-xian county was circumfluenced in 80% ethanol to remove the lipophilic fraction.Rude polysaccharide was obtained by adding ethanol to its concentrated solution extracted in distilled water.The rude polysaccharide was dissolved in distilled water and was deproteinized by repeated freeze thawing,then the different polysaccharide fractions were isolated by ultrafiltration.The contents of the total sugar and the protein of these fractions were determined.Results Three fractions with different molecular weight of 10 ~30 kD,30 ~300 kD and 300 kD were obtained.The colors of these fractions were dark brown,light yellow and off-white color,respectively.The total sugar content was 40.15%,62.12% and 80.33%,respectively.The protein content was 2.88%,0.98% and 0.74%,respectively.The main component of Angelica sinensis polysaccharide was the fraction with large molecular weight(300KD),which accounted for 5.48% of dry DangGui.Conclusion The main fraction of Angelica sinensis polysaccharide obtained by ultrafiltration has higher total sugar content and lower protein content and the isolation by ultrafiltration is easy to operate,hence,it is suitable to isolate Angelica sinensis polysaccharide fractions in large scale.