Abstract

The Ionic liquid (IL) has been used as microwave assisted extraction (MAE) solvent for extraction of various compounds from crude samples because it has good physical and chemical properties, including unvaporized, good stability, viscosity, solubility, and extraction ability to different organic compounds, and can absorb the microwave energy efficiently.
The objective of this study was to investigate the efficacy of using ionic liquid-based microwave-assisted (IL-MAE) approach for extraction of oxyresveratrol from Morus alba roots and to compare the result with conventional extraction.
The roots were extracted with nine IL, 1-butyl-3-methylimidazolium chloride (BmimCl), 1-butyl-3-methylimidazolium bromide (BmimBr), or 1-butyl-3-methylimidazolium tetrafluoroborate (BmimBF4) at concentration 1.5, 1.67, and 2 M for each IL, in a microwave at Power 30% for 10 minutes respectively. The extracts were filtrated and diluted with 30 ml of deionized water. Then, fractionated with ethyl acetate and salting out by addition of Na2CO3 or KH2PO4. The fractions were analyzed for oxyresveratrol contents with TLC-densitometer and HPLC. Then the result was compared with conventional methods.
IL-MAE approach showed improved extraction efficiency compared to the conventional ethanol and methanol macerations. The optimized solvent condition for extraction of oxyresveratrol from Morus alba root was 1.5 M BmimCl with 0.01 M KH2PO4 salt. Oxyresveratrol was separated by ethyl acetate fractionation, and the yield calculated was 3.53% from raw material.

Key words: ionic liquid, oxyresveratrol, Morus alba, ionic liquid-based microwave-assisted extraction.