Characterization of Flavonoids and Phytoestrogens in an Extract of Pueraria Mirifica by UHPLC-MS-MS

Authentic standards for several key flavonoids were fully characterized by UHPLC and MS. MS measurement was carried out in several modes, including full scan, selected ion monitoring, multiple reaction monitoring, and product ion scan modes. Tandem mass spectra were compared with authentic standards or published spectra to propose identifications for each compound. In particular, the tandem mass spectra of O-linked and C-linked flavonoid glycosides were examined and could be distinguished based on the fragmentation patterns of the glycoside ring. In addition, several isomers of deoxymiroestrol were detected and identified based upon their similar fragmentation patterns. Further characterization may reveal additional information about other compounds in the P. mirifica extracts. Lastly, the levels of daidzein and puerarin were accurately quantitated using MRM. The calibration curves were linear over the tested range of 43 to 22,000 ng/mL.