Separation and Purification of Five Anthraquinones from Crude Extracts of Rhubarb

The effect of separation of five anthraquinones in rhubarb by macroporous resin was investigated through static adsorption experiment in this paper. The sorption and desorption properties of five anthraquinones(aloe-emodin,rhein,emodin,chrysophanol,physcion)on macroporous resins including HPD-100,XDA-6,AB-8,LX-38,ADS-7 and ADS-17 had been compared. Then,Dynamic adsorption and desorption were performed on the chosen macroporous resin packed in glass columns to optimize the separation process.Results showed that,HPD-100 resin offered much higher adsorption and desorption ratios for five anthraquinones than other resins;under the optimised conditions:the ratio of column height to diameter bed 1∶8,loading concentration 3.64 mg/mL,loading volume 2.0 BV,flow rate 1.0 BV/h,85% ethanol as eluent,and elution volume 3 BV,the dynamic adsorption and desoption rate of five anthraquinones on HPD-100 were 86.3% and 85.9%,respectively. The content of five anthraquinones in the final product increased 2.88-times from 7.13% to 20.5%,with a recovery of 98.7%,ionic liquidsbmimBr could be removed from crude extract,which showed that the optimized conditions were feasible.