title: Ionic Liquid-Based Ultrasonic-Assisted Extraction of Forsythosides from the Leaf of Forsythia suspensa (Thunb.) Vahl and Subsequent Separation and Purification by High-Speed Counter-Current Chromatography.
abstract: An ionic liquid-based ultrasonic-assisted extraction (ILUAE) method was developed for the extraction of the two forsythosides, namely forsythosides I and A from the leaf of Forsythia suspensa (Thunb.) Vahl. Three kinds of l-alkyl-3-methylimidazolium ionic liquids with different alkyl chain and anion were investigated. The results indicated that ionic liquids showed remarkable effects on the extraction yields of forsythosides. In addition, several ILUAE ultrasonic parameters, such as the solvent concentration, solvent to solid ratio and extraction time have been optimized. Under these optimal conditions (e.g., with 0.6 M [C6MIM]Br, solvent to solid ratio of 15 mL/g and extraction time of 10 min), this approach gained the highest extraction yields of forsythoside I (0.89%) and forsythoside A (10.74%). Meanwhile, forsythosides in the ILUAE extract were separated and purified successfully through the high-speed counter-current chromatography with a two-phase solvent system consisting of ethyl acetate-ethanol-acetic acid-water (4 : 1 : 0.25 : 6, v/v). 5.4 mg of forsythoside I and 59.7 mg of forsythoside A were obtained from 120 mg of the prepurified sample in one-step separation, with the purity of 96.1 and 97.9%, respectively, as determined by high-performance liquid chromatography. Their structures were identified by (1)H nuclear magnetic resonance (NMR) and (13)C NMR.
authors.affiliation: Institute of Special Animal and Plant Sciences, Chinese Academy of Agricultural Sciences, 130112 Changchun, China sunyinshi2015@163.com.
authors.forename: Yinshi
authors.initials: Y
authors.lastname: Sun
authors.affiliation: College of Resource and Environmental Science, Jilin Agricultural University, 130118 Changchun, China.
authors.forename: Zhiguang
authors.initials: Z
authors.lastname: Hou
authors.affiliation: Institute of Special Animal and Plant Sciences, Chinese Academy of Agricultural Sciences, 130112 Changchun, China.
authors.forename: Zhengbo
authors.initials: Z
authors.lastname: Liu
authors.affiliation: College of Agronomy, Shandong Agricultural University, 271018 Taian, China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Wang
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods*; D003377:Countercurrent Distribution; D031657:Forsythia / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification*; D052578:Ionic Liquids / Q000737:chemistry*; D010936:Plant Extracts / Q000302:isolation & purification*; D018515:Plant Leaves / Q000737:chemistry; D014465:Ultrasonics
chemical_list: D006027:Glycosides; D052578:Ionic Liquids; D010936:Plant Extracts