Preparation of three flavonoids from the bark of Salix alba by high-speed countercurrent chromatographic separation

The main flavonoids from the bark extract of Salix alba (Salicaceae) were separated on preparative scale using high-speed countercurrent chromatography (HSCCC). In each separation, 1.0 g crude extract was applied to yield pure eriodictyol (120 mg), 5,7-dihydroxychromen-4-one (29.5 mg), and naringenin (50 mg), respectively, while water-methanol-ethyl acetate-n-hexane (3:2:2:2, v/v) was used for a two-phase solvent system. The chemical structures of three flavonoids were elucidated by means of electrospray ionization ion trap multiple mass spectrometry (ESI-MS-MS), as well as H-1-, C-13-, and DEPT-NMR spectroscopy.