Simultaneous determination of 35 constituents and elucidation of effective constituents in a multi-herb Chinese medicine formula Xiaoer-Feire-Kechuan

Xiaoer-Feire-Kechuan (XFK) is an 11-herb Chinese medicine formula to treat cough and pulmonary inflammation. The complicated composition rendered its chemical analysis and effective-component elucidation. In this study, we combined quantitative analysis and bioactivity test to reveal the anti-inflammatory constituents of XFK. First, UPLC-DAD and UHPLC/Q-Orbitrap-MS methods were established and validated to quantify 35 analytes (covering 9 out of 11 herbs) in different XFK formulations. Parallel reaction monitoring mode built in Q-Orbitrap-MS was used to improve the sensitivity and selectivity. Then, anti-inflammatory activities of the 35 analytes were analyzed using in vitro COX-2 inhibition assay. Finally, major analytes forsythosides H, I, A (8–10), and baicalin (15) (total contents varied from 21.79 to 91.20 mg/dose in different formulations) with significant activities (inhibitory rate ≥ 80%) were proposed as the anti-inflammatory constituents of XFK. The present study provided an effective strategy to discover effective constituents of multi-herb formulas.