Optimization of ionic liquid-based homogenate extraction of orientin and vitexin from the flowers of Trollius chinensis and its application on a pilot scale

In this present work, orientin and vitexin were effectively extracted from Trollius chinensis flowers using ionic liquid-based homogenate extraction (ILHE) method. 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim]BF4) was selected as the extraction solvent. The optimum conditions of 1.10 M ionic liquid concentration, 4 min homogenate time, 23 mL/g liquid-solid ratio and one extraction cycle for the ILHE process were obtained after investigating by single factor experiments, extraction kinetics and Box-Benhnken design. Under the optimum conditions, satisfactory extraction yields of orientin (5.66 ± 0.18 mg/g) and vitexin (0.85 ± 0.03 mg/g) were obtained by the pilot-scale homogenate equipment. The kinetic curves of orientin and vitexin were studied, and the phenomenon was explained in detail on the base of visual photograph and percentages of different particle sizes of T. chinensis flowers after ILHE for different times. Relative to other methods, not only the time consumption was shortened to only 4 min for the proposed approach, but also the extraction yields were improved greatly. Meanwhile, effective separation of the target analytes from [C4mim]BF4 ionic liquid extraction solution was realized after the adsorption and desorption on HPD100B macroporous resin in a pilot scale, with the recovery yield of 82.86% for orientin and 84.71% for vitexin, respectively. The total recovery yield of [C4mim]BF4 ionic liquid was 97.48% in the whole process. Therefore, the environmentally friendly ILHE method proposed in this work is a convenient, effective and rapid technique, and has superiority in extraction of active ingredients from plant materials.