Improved Curcumin Recovery and In Vitro Biological Activity of Turmeric Extracts Using Nipa Palm Syrup– and Nipa Palm Vinegar–Based Natural Deep Eutectic Solvent (NADES) Hybridized with Microwave-Assisted Extraction

This was the first study to use local Southern Thai ingredients, namely, nipa palm syrup (NS) and nipa palm vinegar (NV), in the formulation of natural deep eutectic solvent (NADES) for the recovery of bioactive curcumin from turmeric. Five NADES formulations (A to E) were obtained by varying concentration of liquid media (NS, NV, and water) and characterized using FTIR. When compared to other formulations and 80% methanol, the NADES D with a NS to NV to water ratio of 1:5:5 ( w / w / w ) recovered the most curcumin content ( p