Metabolite profile analysis of aconitine in rabbit stomach after oral administration by liquid chromatography/electrospray ionization/multiple-stage tandem mass spectrometry.

1. Aconitine (AC), an active and highly toxic constituent extracted from aconitum plants, is well known for its excellent effects against rheumatism and rheumatoid arthritis. The metabolism of AC in liver and intestine has been previously reported. However, little is known about the metabolism of AC in stomach. In this study, the metabolite profiling of AC in stomachs of rabbit and rat was performed by liquid chromatography/electrospray ionization/multiple-stage tandem mass spectrometry (LC/ESI/MS(n)), for the first time. 2. The samples were purified by liquid-liquid extraction, separated using an Agilent extended C18 column following a linear gradient elution and then detected by ESI/MS(n) in positive ion mode. Metabolites were identified by comparing their protonated molecules, fragmentation patterns and chromatographic behaviors with those of standard compounds and data from authorized literature works. 3. In conclusion, 14 metabolites were identified in animal stomach after oral administration of AC. The presentation of a large amount of metabolites of AC in stomach suggested that, for aconitum alkaloids, the stomach might play an important role in their metabolism.