title: Isolation and characterization of methoxylated flavones in the flowers of Primula veris by liquid chromatography and mass spectrometry.
abstract: Characterization of six flavones, which were named substances G1, G2, G3, G4, G5 and G6 according to their R(F) values in normal-phase thin-layer chromatography, is reported. The pure flavones were purified after maceration with methanol by normal-phase solid-phase extraction, normal-phase medium-pressure liquid chromatography, normal-phase preparative thin-layer chromatography and preparative reversed-phase high-performance liquid chromatography (RP-HPLC). The collected fractions of several isolation steps were analyzed by normal-phase (NP) and RP-HPLC. Detection and identification of the substances G was accomplished by UV detection at 213-216 nm, diode array UV detection, or fluorescence detection (lambda(ex)=330 nm; lambda(cm)=440 nm). The molecular mass, the elementary composition, and the structure of the six components was determined by electron-impact high-resolution mass spectrometry (EI-HRMS). Substance G4 was identified as 3',4',5'-trimethoxyflavone. The substances G1-G6 were shown to be mono-, di- tri- and pentamethoxyflavones. HPLC-electrospray ionization tandem mass spectrometry (ESI-MS-MS) of the flavones was carried out employing a 150x2 mm I.D. column packed with a 3 microm/100 A octadecylsilica stationary phase and a mobile phase comprising 1.0% acetic acid in water-acetonitrile (50:50). Comparative RP-HPLC-ESI-MS of the raw methanol extract and the isolated substances G1-G6 proved that the isolated compounds were pure and were not artifacts. Finally, RP-HPLC-ESI-MS-MS was used to identify substances G1-G6 in phytopharmaceutical drugs.
authors.affiliation: Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens-University, Innsbruck, Austria.
authors.forename: C W
authors.initials: CW
authors.lastname: Huck
authors.forename: C G
authors.initials: CG
authors.lastname: Huber
authors.forename: K H
authors.initials: KH
authors.lastname: Ongania
authors.forename: G K
authors.initials: GK
authors.lastname: Bonn
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification*; D013058:Mass Spectrometry; D010945:Plants, Edible / Q000737:chemistry*
chemical_list: D005419:Flavonoids