Rapid characterization of chemical constituents and rats metabolites of the traditional Chinese patent medicine Gegen-Qinlian-Wan by UHPLC/DAD/qTOF-MS

Gegen-Qinlian-Wan (GQW) is a popular traditional Chinese patent medicine for the treatment of diarrhea. It is composed of four herbal medicines, Puerariae Radix, Scutellariae Radix, Coptidis Rhizoma, and Glycyrrhizae Radix. In this study, a rapid and sensitive method based on ultra high-performance liquid chromatography coupled with diode-array detection and quadrupole time-of-flight mass spectrometry (UHPLC-DAD-qTOF-MS) was established to characterize the chemical constituents and rats metabolites of GQW. Samples were separated on an Agilent Zorbax Eclipse Plus-C-18 column (100 mm x 2.1 mm, 1.8 mu m) by gradient elution using acetonitrile and water containing 0.1% formic acid as the mobile phase. On the basis of UV and qTOF high-accuracy mass spectral analysis, a total of 62 compounds were identified or tentatively characterized from GQW, including 42 flavonoids, 8 alkaloids, 6 triterpenoids, 3 phenylethanoid glycosides, and 3 other types. Among them, 27 compounds were confirmed by comparing with reference standards. Furthermore, metabolites in rats plasma and urine after oral administration of GQW were also analyzed. A total of 42 compounds were identified, including 29 prototypes and 13 metabolites through metabolic pathways of demethylation, methylation, hydrolysis, sulfate conjugation, and glucuronide conjugation. Glucuronidated flavonoids were the main constituents in the plasma, and were then transformed into aglycones and excreted from urine. This is the first systematic study on the chemical constituents and metabolic profiling of GQW. (C) 2012 Elsevier B.V. All rights reserved.