Optimization and mechanistic study for efficient extraction of curcuminoids from turmeric using a natural hydrophobic deep eutectic solvent.

Curcuminoids, the principal bioactive constituents of turmeric, are in high demand across various industries. Developing efficient and green extraction techniques is therefore crucial. This study introduces a novel natural hydrophobic deep eutectic solvent (HDES) composed of anisyl alcohol and thymol for the ultrasound-assisted extraction of curcuminoids. The extraction process was optimized using single-factor experiments and response surface methodology. Under the optimized conditions, where the liquid-to-solid ratio is 18.64 mL/g, the extraction temperature is 22 °C, the ultrasonication time is 26.5 min, and the extraction time is 60 min, the single extraction obtained a high yield of 62.18 mg/g, significantly surpassing that obtained with conventional methanol. Furthermore, the HDES achieved a remarkable cumulative yield of 456.54 mg/g over multiple extraction cycles, highlighting its sustainability and superior solubility. Mechanistic investigations through molecular dynamics simulations revealed that the high extraction efficiency is primarily governed by van der Waals forces.