Identification of Ursane-type Triterpene Saponins from Zygophyllum coccineum L. in Negative Electrospray Ionization by Tandem Mass Spectrometry

Abstract

Zygophyllum coccineum L., family Zygophyllaceae, grows in Egyptian deserts. It has been used as antihelminthic, diuretic, antidiabetic, antiasthma, antigout, antirheumatic, and antihypertension agent in traditional medicine. Phytochemical investigations revealed that the major secondary metabolites in Z. coccineum L. are a class of quinovic acid compounds belonging to ursane-type triterpene saponins [1]. As a part of research program aimed to characterize different types of triterpene saponins from medicinal plants, a LC-tandem mass spectrometry method was developed for the separation and structural characterization of ursane-type triterpene saponins from Z. coccineum L. The experiment was conducted on a Waters Xevo QTOF system using a C-18 column material as stationary phase; the mobile phase was composed of alcohol/acetonitrile and water, both containing 0.5% formic acid. Mass spectra were obtained of two sub-groups, in which sugar chains connected at both C-3 and C-28 or C-3 only, were discovered, and their fragmentation pathways were proposed. Eighteen saponins together with narcissin, a flavonoid glycoside were determined or tentative identified from Z. coccineum L. on the basis of proposed pathway and comparing with reference standards. Acknowledgements: This research is supported in part by Science Based Authentication of Dietary Supplements funded by the Food and Drug Administration grant No. 1U01FD004246–01; the United States Department of Agriculture, Agricultural Research Service, Specific Cooperative Agreement No. 58–6408–2-0009, and the Global Research Network for Medicinal Plants (GRNMP), King Saud University.