UPLC-Q-TOF/MS for Analysis of the Metabolites of Flavone Glycosides from Scutellaria baicalensis Georgi by Human Fecal Flora in Vitro

Abstract

The active ingredients of Scutellaria baicalensis Georgi, a valuable traditional Chinese medicine, are polyhydroxyflavones, namely baicalin, scutellarin and wogonoside. However, information about the metabolic routes, metabolites and even more the effect of chemical structure on the stability of the three has been limited. In this article, the three natural compounds were incubated with human fecal flora, respectively, and highly sensitive and specific ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry implementing the MetaboLynx™ software method was used for the drug metabolism study. The chromatographic separation was performed on a 1.7-μm particle size Syncronis C18 column using a gradient elution system. The components in the extract were identified and confirmed according to the mass spectrometric fragmentation mechanisms, MS/MS fragment ions and relevant literature by means of electrospray ionization mass spectrometry in negative ion mode. With this method, a total of ten metabolites were identified based on MS and MS/MS data. The results indicated that hydrogenation, methylation and deglycosylation were the major metabolic pathways of the three flavone glycosides in vitro, and the metabolic stability was closely related to the chemical structure. This study will be helpful for fully understanding the impact of intestinal bacteria on these active components. Furthermore, this work demonstrated the potential of the ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry approach with MetaboLynx for quite rapid, simple, reliable and automated identification of metabolites of natural products.