Structural identification of the metabolites of ganoderic acid B from Ganoderma lucidum in rats based on liquid chromatography coupled with electrospray ionization hybrid ion trap and time-of-flight mass spectrometry.

Ganoderic acid B (GAB), a representative triterpenoid in Ganoderma lucidum, possesses various pharmaceutical effects and has been used as a chemical marker in quality control of G. lucidum and related products. The metabolites of GAB in vivo after its oral administration to rats were investigated by liquid chromatography coupled with electrospray ionization hybrid ion trap and time-of-flight mass spectrometry. A total of 14 metabolites of GAB in rat plasma, bile and various organs were detected and identified by direct comparison with the authentic compounds and their characteristic mass fragmentation patterns. The results showed that oxidization and hydroxylation were the common metabolic pathways for GAB in rats. Moreover, some reduction metabolites of GAB were detected in rat kidney and stomach and glucuronidation only appeared in rat bile. This is the first report on the metabolites of GAB in vivo.