Effective ultrasonic-assisted extraction and solubilization of curcuminoids from turmeric by using natural deep eutectic solvents and imidazolium-based ionic liquids

• Green method was developed for curcuminoids extraction from turmeric. • Natural choline- based deep eutectic solvents and imidazolium-based ionic liquids were used. • A high-yielding extraction of curcuminoids is possible with these green solvents. • The curcuminoids solubility was measured in the presence of the investigated solvents. • Hansen solubility parameter is an effectively accurate tool to predict the behavior of extraction systems. Curcuminoids (CURs), bioactive and antioxidant polyphenols, are major components of turmeric. Commercially available component in CURs are curcumin (C) as the main constituent and the other two demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC) as minor components. Extraction and analysis of these components from turmeric may pose specific challenges and yield different results. The organic solvents applied in traditional solvent extraction systems are not eco-friendly owing to their properties such as flammability, toxicity and volatility. For this reason, in this research work, ten deep eutectic solvents (DESs) and three ionic liquids (ILs) were selected to investigate the extraction of CURs from turmeric. Further, DES and ILs-based extraction was performed under ultrasound. Under extraction conditions, the CURs in the turmeric powder was measured by the use of high performance liquid chromatography (HPLC). The maximum CURs amount of 164.51 mg/g was attained using effective ultrasound-assisted extraction in 50% water content DES or IL at 5% solid loading with 50.8 W/cm 2 power intensity at 363 K in 60 min. This improved extraction method can be economical, green and effective alternative to conventional solvent extraction for CURs. On the other hand, the solubility of standard CUR was obtained at 298.15 K using saturation shake flask method. Finally, Hansen solubility parameters (HSP) were applied to identify solvents which were compatible with CURs. All the results were consistent with each other, supporting the validity of our extraction method.