Rapid Profiling and Identification of Triterpene Saponins in Three Different Cephalaria Species by UPLC-ESI-MS/MS

Abstract

Triterpene saponins are bioactive glycosides which are responsible for the defense mechanism of the plants and have extensive structural diversity in many plant species. In this study, profile of triterpene saponins was determined in the crude n-BuOH extracts of Cephalaria hirsuta, Cephalaria elazigensis var. elazigensis, and Cephalaria procera taxa (Caprifoliaceae) by ultra pressure liquid chromatography coupled with electrospray ionization tandem mass spectrometry. The UPLC-ESI-MS/MS method has been validated to provide linearity, recovery, precision (repeatability), limit of detection and limit of quantification parameters for quantitative analysis. Identification and quantification of the compounds were based on a group of fragment ions and ESI-MS spectra; precursor ions were observed as [M+Na] + and [M+H] + in positive mode for molecular mass information. Thirty nine saponins were identified and quantified by reversed-phase liquid chromatography (RP-LC) and they were separated on C18 reverse phase column (50 mm x 2.1 mm, 1.7 µm) by methanol-water gradient containing 0.1 mM ammonium formate solution as a mobile phase. Among the detected compounds, 28 compounds in C. hirsuta, 4 compounds in C. elazigensis var. elazigensis and 22 compounds in C. procera were identified and quantified based on their retention times and mass spectra in comparison with the data of references which were isolated in our previous studies. In this study, rapid application of an UPLC-ESI-MS/MS approach for resolving the chemical content of complex crude n-BuOH extracts of three Cephalaria species were presented, for the first time.