Preparative separation and purification of rosavin in Rhodiola rosea by macroporous adsorption resins

Rosavin is one of the main bioactive components in Rhodiola rosea L. with known pharmacological effects. In this study, a simple method for preparative separation and purification of rosavin from R. rosea L. was developed with macroporous adsorption resins. The adsorption isotherms and desorption performances of some resins have been determined and compared. Depending on its hydrophobic force, HPD-200 resin, a styrene-divinylbenzene (SDVB) copolymer, offers the best adsorption and desorption properties for rosavin based on the research results, its adsorption data fit best to the Langmuir adsorption model. Dynamic adsorption and desorption was performed on HPD-200 resin packed in a glass column to obtain optimal parameters for the separation of rosavin. The optimum conditions were as follow. The volume, concentration, bed height and flow rate of loading sample were 4 bed volumes (BV), 0.24 mg/mL, 30 cm and 2 BV/h, respectively, at 25 °C; desorption was performed successively with 30% ethanol of 4 bed volumes, 40% ethanol of 2.5 bed volumes and 60% ethanol of 3 bed volumes. After one run treatment with HPD-200, the rosavin content in the product was increased from 0.69% to 11.02% with a recovery of 82.46%. In this case, the process throughout is 1.34 g rosavin/L adsorbent/day, solvent usage is 7.14 L ethanol/g rosavin. The simple purification scheme avoids toxic organic solvent and thus, increases the safety of the process with a potential industrial application prospect.