Study on the metabolites of isoalantolactone in vivo and in vitro by ultra performance liquid chromatography combined with Triple TOF mass spectrometry

Isoalantolactone (IAL) is an active sesquiterpene naturally present in many vegetables, condiments and medicinal plants. In this study, an efficient strategy was developed for the identification of metabolites following the in vivo metabolism and in vitro biotransformation of IAL with rat intestinal bacteria utilizing ultra performance liquid chromatography combined with Triple TOF mass spectrometry (UPLC-Triple TOF-MS/MS). As a result, 46 metabolites including 34 novel sulfur-containing products were identified. The results demonstrated that IAL could undergo general metabolic reactions, including oxidation, hydration, hydrogenation, demethylation, cysteine conjugation and N-acetylcysteine conjugation, but the most noticeable characteristic of IAL metabolism was the H2S addition to the double bond between C-11 and C-13 and subsequent reactions to produce a series of novel sulfur-containing dimers. This is the first study of IAL metabolism in vivo, whose results provide novel and useful data for a better understanding of the safety and efficacy of IAL.