Enrichment of rosmarinic acid from Salvia przewalskii Maxim. leaves using macroporous resin: Adsorption/desorption behavior, process optimization followed by scale-up

To valorize Salvia przewalskii Maxim. leaves as a renewable source of rosmarinic acid, an efficient macroporous resin enrichment technology was established in this work. X-5 resin was considered as the most appropriate adsorbent in view of its highest adsorption/desorption capacity for rosmarinic acid, and the adsorption data were best expounded by Langmuir isotherm model and pseudo-second-order kinetics model. The influences of sample volume, loading and elution flow rates, eluent type and volume were evaluated to obtain the optimum enrichment procedure, which was as follows: for adsorption, the rosmarinic acid concentration, loading flow rate and sample volume were respectively 0.24 mg/mL, 3 BV/h, and 12 BV; for desorption, the eluent type, elution flow rate and volume were respectively 50% ethanol, 3 BV/h and 9 BV. Furthermore, an enrichment process scale-up of rosmarinic acid was performed under optimal procedure. After one-step large-scale enrichment, the content of rosmarinic acid improved 3.65-fold from 12.41% to 45.30% with a satisfactory recovery of 80.17%. Results suggested that X-5 resin chromatographic enrichment technique developed in the present study offered a feasible scheme for the industrial enrichment of rosmarinic acid from S. przewalskii leaves.