Enhancing the water extraction of shikimic acid using natural deep eutectic solvents

Natural deep eutectic solvents (NADESs) were applied as green promoters of the water extraction of shikimic acid from Illicium verum fruits. Our studies showed that 10 wt% aq. [Ch]Cl:PropGly (1:3) allows efficient extraction of shikimic acid at a lower temperature and shorter extraction time as compared to water alone. In-depth NMR studies revealed that the components of the investigated NADES retain their supramolecular assembly and interact with shikimic acid even at high dilutions, thus remaining effective as co-solvent. The solvent composition, consisting primarily of water, underscores the role of NADES as a co-solvent in the development of tailor-made extraction processes that enhances extraction performance while maintaining environmental sustainability. Subsequent purification steps, involving selective precipitation with formaldehyde and ion-exchange chromatography, and recrystallization afforded shikimic acid in good isolated yield and purity (4% w/w yield, 99.5% purity).