Extracting phytochemicals from Eleutherococcus senticosus using natural low-melting mixtures: Experimental and molecular simulation

In this study, a series of natural low-melting mixture solvents (NLoMMSs) were prepared using choline chloride as the hydrogen bond acceptor and various compounds as the hydrogen bond donor for the extraction of principal phytochemicals, namely eleutheroside B, eleutheroside E, rutin, hyperoside, and quercitrin from E. senticosus. The optimal NLoMMS was determined to comprise lactic acid to choline chloride with a molar ratio of 3:1, accompanied by a water content of 30 %. In comparison to other extraction solvents, the prepared NLoMMS serve as a green and sustainable extraction medium, which shows high extraction yield for phytochemicals in E. senticosus. The optimal extraction conditions were determined to be: an extraction time of 20 min, an extraction pressure of −0.07 MPa, and a liquid-solid ratio of 20 mL/g. The surface morphology and functional groups of phytochemicals before and after extracting by NLoMMS were systematically characterized. It was observed that NLoMMS could more effectively destroy the cell wall, which was conducive to the efficient extraction of phytochemicals. Furthermore, the extraction mechanism of phytochemicals by NLoMMS was explored by molecular dynamics simulation. The results indicate that van der Waals forces, hydrogen bonding, and electrostatic interactions are the primary interaction forces between NLoMMS and phytochemicals.