Rapid separation and characterization of active flavonolignans of Silybum marianum by ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry

Ultra-performance liquid chromatography (UPLC) interfaced with the electrospray ionization (ESI) tandem mass spectrometer (MS n ) was developed for the simultaneous determination of silychristins A ( 1) and B ( 2), silydianin ( 3), silybins A ( 4) and B ( 5), and isosilybins A ( 6) and B ( 7), major bioactive flavonolignans in silymarin, a herbal remedy derived from the milk thistle Silybum marianum. In this study, the seven major active flavonolignans including the diastereomers 1/ 2, 4/ 5, and 6/ 7 were completely separated using UPLC with an ACQUITY UPLC C 18 column and a MeOH/water/formic acid mobile phase system. The collision-induced dissociation (CID) MS n spectra of these flavonolignans were studied systematically using ESI-MS. The results with the present methodology show that UPLC–MS n can be useful for general screening of active natural products from plant extracts and for the specific quality control of silymarin.