The metabolites and pharmacokinetics of ganoderic acid C2 (GAC2), a bioactive triterpenoid in Ganoderma lucidum in rat plasma were investigated by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC–ESI-MS/MS). Totally, ten minor phase I metabolites of GAC2 were characterized after oral administration of GAC2, on the basis of their mass fragmentation pathways or direct comparison with authentic compounds by high-performance liquid chromatography coupled with diode array detection and electrospray ion trap tandem mass spectrometry (HPLC–DAD–ESI-MSn), and liquid chromatography coupled with electrospray ionization hybrid ion trap and time-of-flight mass spectrometry (LC–ESI-IT-TOF/MS) methods. Moreover, a rapid and specific method for quantification of GAC2 in rat plasma after oral administration was developed by using a liquid–liquid extraction procedure and HPLC–ESI-MS/MS analysis. It is the first time to report the metabolites and pharmacokinetics of GAC2.Graphical abstractProposed metabolic pathways of ganoderic acid C2 (M0) in rats.Highlights► Ten minor phase I metabolites were characterized. ► A rapid quantification method was developed by LC–MS/MS. ► The metabolites and pharmacokinetic of GAC2 were reported firstly.

Triterpenoids are the main bioactive components of Ganoderma lucidum, a famous traditional Chinese medicine. After oral administration of total triterpenoids of G. lucidum (TTGL), the rat bile was analyzed by high-performance liquid chromatography coupled with diode array detection and electrospray ion trap tandem mass spectrometry (HPLC-DAD–ESI-MSn) and liquid chromatography coupled with electrospray ionization hybrid ion trap and time-of-flight mass spectrometry (LC–ESI-IT-TOF/MS). From rat bile and TTGL samples, a total of 31 triterpenoids, including seven new compounds, were identified or tentatively characterized based on their fragmentation behaviors. Among them, 22 triterpenoids were identified from TTGL and 29 triterpenoids were detected from rat bile after oral administration of TTGL. The results indicated that the majority of triterpenoids detected in TTGL extract could be excreted through rat bile. It is the first report on excretion of total triterpenoids of G. lucidum in rat bile.Highlights► The HPLC-DAD–ESI-MSn and LC–IT-TOF/MS methods were used to identify the major compounds in rat bile after oral administration of total triterpenoids of Ganoderma lucidum (TTGL). ► A total of 31 triterpenoids were identified or tentatively characterized from rat bile and TTGL extract. ► The majority of triterpenoids detected in TTGL extract could be excreted through bile after oral administration of TTGL to rats. ► It is the first report on excretion of total triterpenoids of G. lucidum in rat bile.