Identification of flavone aglycones and glycosides in soybean pods by liquid chromatography-tandem mass spectrometry

High-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry was used to identify flavone aglycones and glycosides in soybean pods. Tandem mass spectrometry (MS-MS and MS-MS-MS) and photodiode array detection were also utilized in flavone characterization. A total of seven flavone aglycones and glycosides were identified. Among them three flavone aglycones-apigenin, 7,4'-dihydroxyflavone, and luteolin-and two flavone glycosides-apigenin-7-O-beta-D-glucoside, and luteolin-7-O-beta-D-glucoside-were unambiguously identified based on their abundant (M+H)(+) ions, UV spectra, retention time, and tandem mass spectrometric analysis compared with authentic standards. The tentative identification of two flavone glycosides as 7,4'-dihydroxyflavone-7-O-beta-D-glucoside and apigenin-7-O-beta-D-glucoside-6"-O-malonate was based on UV spectra, (M+H)(+) ions, and tandem mass spectrometry. This is the first report identifying flavone aglycones and glycosides in soybean pods. Published by Elsevier Science B.V.