NADES-based surfactant-free microemulsions for solubilization and extraction of curcumin from Curcuma Longa. (1st September 2021) - Huber, Verena
Highlights: Water can be replaced by a ChCl + Lac (1:1) NADES in a surfactant-free microemulsion. Choline chloride + lactic acid/ethanol/triacetin forms food-agreed, green SFMEs. Curcumin solubility can be increased twofold by NADES addition to Ethanol/Triacetin. Through multiple cycles of extraction, the solvent can be enriched in curcuminoids. The cycle NADES-SFME extraction saves solvent, is easy, high-yielding, and green. Abstract: A choline chloride + lactic acid (1:1) natural deep eutectic solvent (NADES) is used as an adjuvant to ethanol/triacetin mixtures to solubilize and extract curcumin from Curcuma Longa . The obtained NADES/ethanol/triacetin mixtures are homogeneous, transparent and of low viscosity even in the absence of water. Dynamic light scattering revealed significant nanostructures, typical of surfactant-free microemulsions. A twofold increase of curcumin solubility and remarkable extraction power (yield of ~90%) can be achieved in the ternary system including the NADES, although curcumin is hydrophobic and the used NADES are very polar. Due to the elevated solubility of curcumin, more extraction cycles can be made than in the previously published aqueous systems with the same amount of solution. As a result, less solvent is required to achieve the same extraction yield.