Identification of Isoflavonoids from Leaves of Pueraria montana (Lour.) Merr. var. lobata (Willd.) and its Comparative Studies with Roots of Pueraria lobata by Using HPLC-ESI-MSD-TOF and MS-MS Methods

Abstract

Radix of Pueraria spp. is a popular traditional Chinese medicine. Kudzu has been traditionally used in China to treat diabetes, alcoholism, gastroenteritis (inflamed stomach or intestine), and has shown to have cardiovascular, neurological, anti-oxidant properties [1,2]. Kudzu (Pueraria lobata, Family Fabaceae) is a rich source of isoflavones and isoflavone glycosides, which include puerarin, daidzin, genistin, genistein, daidzein, and daidzein-4', 7-diglucoside. Puerarin and daidzin were the major isoflavone glucosides in kudzu root in comparison with kudzu leaf. LC-MSD-TOF and MS-MS tools have been employed for profiling and characterization of isoflavones and isoflavone glycosides including distinction between flavonoid O- and C-glycosides. The mass spectrum of O-glycoside is generally characterized by the presence of an abundant fragment ion resulting from (terminal) glycosyl cleavage and the aglycone moiety of C-glycoside was not produced. Thus puerarin (m/z = 416.10) and daidzin (m/z = 416.10) are readily distinguished. These two glucosides with [M-H]− at m/z 415.10 and [M+H]+ at m/z 417.12 were well resolved chromatographically (tr = 17.83 and 20.18 min). These were characterized by losses of 120 and 162 amu upon fragmentation, respectively. The loss of 120 amu is characteristic of C-glycoside flavonoids. Acknowledgements: This research is funded in part by “Science Based Authentication of Dietary Supplements” Funded by the Food and Drug Administration grant number 2 U01 FD 002071-07. The authors would like to thank Annette Ford, University of Mississippi for extraction of samples.