Rapid identification of chemical components in vitro and in vivo of Menispermi Rhizoma by integrating UPLC-Q-TOF-MS with data post-processing strategy

Introduction Menispermi Rhizoma (MR), the dried rhizome of Menispermum dauricum DC. (Menispermaceae), has been used to treat sore throat, enteritis, dysentery, and rheumatic arthralgia. Despite extensive research on its pharmacological effects, the chemical components in vitro and in vivo have not been thoroughly studied. Objective To establish an efficient method for rapid classification and identification of alkaloids in MR and its preparations, as well as metabolites in vivo after oral administration of MR. Methods Rapid identification of alkaloids and absorbed components of MR was performed using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) coupled with UNIFI software. Moreover, the characteristic fragmentations and neutral losses of different types of alkaloids in MR were summarised to realise the rapid classification of alkaloids. Results A total of 55 components were unambiguously or tentatively identified in MR. Among them, 37 and 31 components were found in MR capsules and tablets, respectively. Meanwhile, 109 compounds were tentatively identified in rat plasma, urine and faeces, including 55 prototypes and 54 metabolites. Hydrogenation, hydroxylation, methylation, glucuronic acid and sulphate conjugations were the dominating metabolic fates of alkaloids. Conclusion The data post-processing strategy established could greatly enhance the structural identification efficiency. The results obtained might lay the foundation for further interpretation of clinical effects, mechanism of action and quality control of MR.