Preparative separation of polyphenols from the flowers of Paeonia lactiflora Pall. by high-speed counter-current chromatography

High-speed counter-current chromatography was used to separate and purify polyphenols for the first time from the flowers of Paeonia lactiflora Pall. with two solvent systems as follows: petroleum ether–ethyl acetate–H2O (1:9:10, v/v/v/v) and petroleum ether–ethyl acetate–butanol–H2O (1:9:0.5:10, v/v/v/v). Eight compounds were separated successfully in single run which were identified as quercetin-3-O-(6″-O-galloyl)-glucoside (I, 41.5 mg), 1,2,3,4,6-trigalloyl-β-d-glucose (II, 106.2 mg), quercetin-3-O-β-d-glucoside (III, 42.3 mg), kaempferol-3-O-(6″-O-galloyl)-glucoside (IV, 23.5 mg), isohamnetin-3-O-β-d-glucoside (V, 34.1 mg), kaempferol (VI, 14.8 mg), kaempferol-3-O-β-d-glucoside (VII, 32.6 mg), kaempferol-7-O-β-d-glucoside (VIII, 23.8 mg) by electrospray ionization–mass spectrometry (ESI–MS) and nuclear magnetic resonance (NMR). The purities of compounds I–VIII were all over 97.0% as determined by HPLC.