Extraction and recovery processes for cynaropicrin from Cynara cardunculus L. using aqueous solutions of surface-active ionic liquids.

Abstract

Due to the wide range of relevant biological activities and high commercial value of cynaropicrin, and aiming at developing cost-effective processes, aqueous solutions of ionic liquids (ILs) were investigated for the extraction and recovery of cynaropicrin from the leaves of Cynara cardunculus L. Both cationic (1-alkyl-3-methylimidazolium chloride) and anionic (cholinium carboxylate) surface-active ILs were investigated, as well as a wide range of conventional surfactants and molecular organic solvents, allowing us to conclude that aqueous solutions of cationic surface-active ILs display a better performance for the extraction of cynaropicrin. Operational conditions were optimized, leading to a cynaropicrin extraction yield of 3.73wt%. The recycling of both the biomass and the solvent were further investigated to appraise the extraction media saturation and to achieve a higher cynaropicrin extraction yield (6.47wt%). Finally, it was demonstrated that 65wt% of the extracted cynaropicrin can be efficiently recovered by precipitation from the IL aqueous extract through the addition of water as anti-solvent, allowing us to put forward both the extraction and recovery processes of the target value-added compound from biomass followed by solvent recycling. This approach opens the door to the development of more sustainable processes using aqueous solutions of ILs instead of the volatile organic solvents commonly used in biomass processing.