Quantitative determination of isoflavonoids in Ononis species by UPLC-UV-DAD

Abstract

Introduction: The root of the Ononis species has been used internally and externally in ethnomedicine for centuries and contains biologically valuable isoflavonoid compounds. Therefore, it is important to obtain quantitative information about the isoflavonoid profile of these plants. Objectives: In this article we aimed to develop an optimised sample preparation protocol alongside a validated method for the quantitative measurement of isoflavones, isoflavanones and pterocarpans in the form of glucosides and aglycones, in order to compare the specialised metabolites of Ononis spinosa L. and O. arvensis L. Material and methods: Quantitative determination was carried out by the means of ultra-performance liquid chromatography coupled with ultraviolet diode-array detection (UPLC-UV-DAD). Results: An optimised sample preparation method was developed to transform malonyl glucosides to their glucosidic forms. Chromatographic methods were created for the baseline separation of isoflavones, isoflavanones and pterocarpans alongside with their glucosides. Altogether 12 compounds were evaluated quantitatively in samples of O. spinosa and O. arvensis. Conclusion: As a result, no characteristic change could be observed between the two species regarding their isoflavonoid pattern.