Analysis and identification of chemical constituents of fenugreek by UPLC-IT-MSn and UPLC-Q-TOF-MS

Fenugreek, a traditional Chinese medical plant, has been widely used as food ingredients because of its outstanding medicinal qualities. The hypoglycemic activity of fenugreek is one of its important pharmacological properties. Both of saponin and flavonoid components have the hypoglycemic activity and their contents in fenugreek are 4%—8% and 1%—2%, respectively. This paper focused on these two types of components to carry out purification research and chemical analysis. The heating reflux extraction method and macroporous resin purification method were designed to prepare the saponins and the flavonoids components from defatted fenugreek seeds. Petroleum ether ultrasonic skim and 70% ethanol refluxing were used for the extraction of saponins and flavonoid from fenugreek. The column of DM130 macroporous resin and D101 macroporous resin were respectively used to prepare fenugreek saponin and flavonoid components, and the total contents of them were 78.56% and 62.28%, respectively. The saponin and flavonoids were subsequently analyzed by an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) along with an ultra-performance liquid chromatography and ion-trap tandem mass spectrometry(UPLC-IT-MSn). As a result, 57 saponins and 19 flavonoid compounds were characterized. The obtained results will provide a theory basis for further research on fenugreek, as well as research and development of hypoglycemic new drugs.