Rapid screening and identification of metabolites of murpanicin in rats by UHPLC/Q-TOF-MS/MS combined with diagnostic fragment ions (DFIs) and multiple mass defect filter

Murpanicin is a main coumarin with obvious anti-inflammatory effect isolated from Murraya species. The primary aim of this research is to identify and characterize the possible metabolites of murpanicin in rats. The metabolites generated in the plasma, urine, bile, and feces of rats were identified and characterized employing ultra-high performance liquid chromatography coupled with quadrupole-time of flight tandem mass spectrometry (UHPLC/Q-TOF-MS/MS) based on diagnostic fragment ions (DFIs) and multiple mass defect filter (MMDF). A total of 67 metabolites were identified, among which 55 are phase I and 12 are phase II reacted products. The plausible structures of the metabolites and the probable metabolic pathways were deduced based on the diagnostic fragment ions, mass ppm error, and mass fragmentation pattern, as well as the MetabolitePilot™ software. The majority of phase I metabolites were generated by demethylation, deethylation, dehydrogenation, hydroxylation, and reduction, while phase II metabolites were mainly generated by glucuronidation and sulfation. Moreover, some rare phase II metabolic pathways, such as N-acetylcysteine conjugation, cysteine conjugation, and S-cysteine conjugation were also observed. In conclusion, our study first expounded the metabolites of murpanicin in rats and provided reference for further clarification of the in vivo therapeutic material basis of murpanicin and other 8-prenylcoumarin derivatives. Moreover, UHPLC/Q-TOF-MS combined with MMDF and DFIs has been proved to be an effective method for rapid identification of the homolog-gathered natural products and their metabolites.