Optimization of Imidazolium-Based Ionic Liquid-Microwave Assisted Extraction for Oxyresveratrol Extraction from Morus alba Roots

Objective: The application of ionic liquids as solvent in the microwave assisted extraction (MAE) method has been developed for extraction of secondary metabolites from plants. However, oxyresveratrol extraction from Morus alba roots using IL-MAE method has never been reported. Purpose of this research was to get the optimum condition of imidazoliumbased ionic liquid-microwave assisted extraction (IL-MAE) for oxyresveratrol extraction from M. alba roots. Methods: M. alba roots were extracted with 3 kinds of ionic liquids (1-butyl-3-methylimidazolium bromide ([Bmim]Br), 1-hexyl-3-methylimidazolium bromide ([Hmim]Br)and 1-butyl-3-methylimidazolium sulfate ([Bmim]2[SO4]), respectively by microwave with 3 different microwave power (P10%, P30% and P50%) for 10 min. Then, fractionated with ethyl acetate and salted out by additionof 4 different salts (Na2CO3, NaHCO3, K2HPO4, and NaCl). Oxyresveratrol concentration of the extracts was analyzed with TLC-densitometry and HPLC. Results: Based on the results of this study, the most optimum condition of IL-MAE for oxyresveratrol from M. alba roots was using [Bmim]Br concentration 1.5mol/L with microwave power 10% for 10 min. The salt 0.01 mol/L NaHCO3 was optimum for the back extraction of oxyresveratrol from [Bmim]Br solution. Under optimized conditions, oxyresveratrol concentration in M. alba roots extract using IL-MAE method was 735.25 ppm. Conclusion: This IL-MAE method was suitable to be applied as an alternative technique to extract oxyresveratrol from the plants.

Key message: Ionic Liquid-Microwave Assisted Extraction seem to be promising method to get optimum oxyresveratrol from Morus alba roots or other plants.