An absorption-based metabolite approach was used to discover and identify the quality markers of MQ. An efficient method based on polarity-switching ultra-performance liquid chromatography triple quadrupole mass spectrometry (UPLC-QQQ-MS/MS) was then established to determine the quality markers.
The absorbed compounds and metabolites were first characterized using UPLC plus Q-Exactive Orbitrap tandem mass spectrometry (UPLC-Q-Exactive Orbitrap-MS) after giving oral MQ extract to rats. Subsequently, the absorbed compounds and precursors of metabolites correlating with the hepatocyte protection activity were screened as quality markers. Finally, a polarity-switching UPLC-QQQ-MS/MS method was developed for the quantitative analysis of the MQ crude drug, enabling the detection of quality markers in both negative and positive ion modes in a single run. The MS2 characteristics of target compounds were investigated to select appropriate product ions.
A total of 13 absorbed compounds and 30 metabolites were characterized. Among these, nine compounds, including five absorbed compounds and four precursors of metabolites intimately correlated with hepatocyte protection activity and absorption
We defined the quality markers and established a universal and rapid method for simultaneously determining the quality markers of MQ, which will be helpful for further investigation of the quality evaluation of MQ in clinical application and the drug market.