Enrichment and Purification of Aucubin from Eucommia ulmoides Ionic Liquid Extract Using Macroporous Resins

Aiming to address the shortcomings of high-concentration ethanol or methanol extraction solutions that need to be diluted and concentrated prior to use in conventional macroporous resin adsorption approaches, an efficient approach for enrichment and purification of aucubin from the ionic liquid extraction solution of samaras of Eucommia ulmoides was proposed. Among the nine kinds of macroporous resins investigated, the HPD850 resin was found to be the most suitable. Equilibrium adsorption tests were investigated and found to be better fitted by the Langmuir isotherm model. After the dynamic tests on a column packed with HPD850, the optimum operational conditions were as follows: for the absorption process, an initial aucubin concentration of 9.87 mg/L, a sample volume of 13 bed volumes (BV), and a flow rate of 2 BV/h; for the water washing process, 5 BV of deionized water and a flow rate of 3 BV/h; for the ethanol desorption process, a 10–80% ethanol volume fraction as the eluent, 2 BV for each ethanol volume fraction, and a flow rate of 3 BV/h. The 40–80% ethanol volume fraction eluent was collected and concentrated to produce the final products, resulting in an aucubin purity and recovery of 79.41% and 72.92%, respectively.