title: One-step separation of three flavonoids from Poacynum hendersonii by high-speed counter-current chromatography.
abstract: BACKGROUND
  Owing to them having the same traditional name, the leaves of Apoacynum venetum and Poacynum hendersonii are used indiscriminately in some areas of China. Although a series of studies have been conducted on Apoacynum venetum, there are only a few studies on Poacynum hendersonii.
  
  
  OBJECTIVE
  To develop an efficient method for the preparative isolation and purification of flavonoids from the leaves of Poacynum hendersonii by high-speed counter-current chromatography (HSCCC).
  
  
  METHODS
  Powdered Poacynum hendersonii lead was extracted three times with 75% ethanol at 60 °C for 3 h. The distribution constant (K(D) ) was measured to select an optimal two-phase solvent system for HSCCC separation. The purities of the target compounds were tested using HPLC and their structures were identified by ¹H-NMR and ¹³C-NMR.
  
  
  RESULTS
  Using a two-phase solvent system composed of n-butanol-petroleum ether-0.5% acetic acid (5:3:5, v/v), three main flavonoids, i.e. isoquercitrin, quercetin-3-O-sophoroside and quercetin-3-O-(6''-O-malonyl)-β-D-glucoside, were separated from 240 mg crude sample in a one-step separation by using HSCCC method. After further purification with a Sepdex-LH20 column, 5.7 mg isoquercitrin (LC purity 98.72%), 4.9 mg quercetin-3-O-sophoroside (LC purity 99.06%) and 7.4 mg quercetin-3-O-(6''-O-malonyl)-β-D-glucoside (LC purity 99.31%) were obtained, respectively.
  
  
  CONCLUSIONS
  The optimised high-speed counter-current chromatography method is fast, simple and efficient for the preparative separation of flavonoids from the leave of Poacynum hendersonii.
authors.affiliation: Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, 810001, China; Graduate School of the Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Junyou
authors.initials: J
authors.lastname: Shi
authors.forename: Guoliang
authors.initials: G
authors.lastname: Li
authors.forename: Honglun
authors.initials: H
authors.lastname: Wang
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.forename: Yourui
authors.initials: Y
authors.lastname: Suo
authors.forename: Jinmao
authors.initials: J
authors.lastname: You
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Liu
mesh_terms: D030010:Apocynum / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003377:Countercurrent Distribution / Q000379:methods; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry
chemical_list: D005419:Flavonoids; D010936:Plant Extracts