A green and designable natural deep eutectic solvent-based supramolecular solvents system: Efficient extraction and enrichment for phytochemicals

Abstract

A green, novel and designable natural deep eutectic solvent-based supramolecular solvents/equilibrium solution (NADES-SUPRAS/EqS) was developed, which possesses better stability and free designability with a wider range of synthesis while compared to the typical alkyl carboxylic acid-based SUPRAS. The physicochemical properties and specific synthesis patterns of NADES-SUPRAS/EqS had been investigated. In addition, a more intelligent solvent regulated synthesis system had been developed to prepare corresponding supramolecular systems according to different polarity target phytochemicals through tailoring the components of synthetic NADES-SUPRAS/EqS. During the NADES-SUPRAS extraction of Zanthoxylum bungeanum Maxim. leaves (ZBML), 18 kinds of NADES were screened and the proportion of NADES as well as the ethanol content were varied tailor. After tailoring, all of the extracted chlorogenic acid, neochlorogenic acid, rutin, as well as 91.775 % of hyperin, 94.940 % isoquercetin and 84.405 % quercetin were distributed in the EqS phase while all of the hydroxy-α-sanshool (HAS) were distributed in the NADES-SUPRAS phase. Furthermore, NADES-SUPRAS/EqS extraction rate reached 9.741 mg/g, which were 7.604-fold, 2.352-fold, 1.141-fold, and 1.384-fold to that of water, ethanol, 70 % ethanol and methanol extraction, respectively. The excellent extraction and separation effects were due to the large number of hydrogen bonds and hydrophobic forces. Dynamic multi-stage countercurrent extraction combined with water and macroporous resin recovery enabled significant cost reductions and rapid recovery of chemical components and solvents. This novel solvent could be intelligently designed and be of great significance for the extraction of different polarity phytochemicals from plants.