Resin adsorption as a means for the enrichment and separation of three terpenoid indole alkaloids: Vindoline, catharanthine and vinblastine from Catharanthus roseus extracts in ionic liquid solution

Simultaneous enrichment and separation of vindoline, catharanthine and vinblastine from Catharanthus roseus (Madagascar periwinkle) ionic liquid extracts was developed. To screen an appropriate resin, 12 commonly used macroporous resins were considered in terms of their performance and characteristics for adsorption and desorption of the target alkaloids. The adsorption capacity and desorption ratio of HPD750 resin for vindoline, catharanthine and vinblastine are found to be higher than that for the other resins, and, thus, this resin was chosen as the most suitable macroporous resin for the enrichment and separation of vindoline, catharanthine and vinblastine. The dynamic adsorption and desorption technical parameters of the target alkaloids were studied and optimized in an HPD750 resin-filled column. The optimum conditions for the adsorption process were determined to be as follows: vindoline, catharanthine and vinblastine loading concentrations in the sample solution of 10.22, 5.41 and 0.98 mg/L, respectively, sample volume of 45 mL, flow rate of 2 BV/h, and a temperature of 25 °C. For the desorption process, 5 BV of pure water was used to wash the impurities and ionic liquid, and then 10–80 % volume fraction of ethanol was used as the eluant (10–30 % volume fraction ethanol was used to remove impurities, and 40–80 % volume fraction ethanol was used to desorb and collect the target alkaloids as the final product). After enrichment and separation under these conditions, the vindoline, catharanthine and vinblastine contents in the products are determined to be 13.59 %, 7.42 % and 1.34 %, with recoveries of 71.37 %, 73.58 % and 75.00 %, respectively. In addition, the recycling of ionic liquid was attempted, which led to the achievement of better results.