Metabolism of Two Mogroside Isomers, Mogroside III and Mogroside IIIE, in Normal and Drug-Metabolizing Enzyme-Induced Rats

Mogrosides III (1) and IIIE (2) are two important bioactive cucurbitane-type triterpenoid triglycosides in the edible fruits of Siraitia grosvenorii (Swingle), which are isomers and have only a minor difference in their structures. To clarify the effects of structural difference and drug-metabolizing-enzyme induction on their metabolism in vivo, their metabolites in normal rats and drug-metabolizing-enzyme-induced rats were tentatively identified and semiquantified by using the HPLC-DAD-ESI-IT-TOF-MSⁿ technique. Totally, 76, 78, 96, and 121 metabolites of mogrosides were identified in the NIII (normal rats orally administered with mogroside III), NIIIE (normal rats orally administered with mogroside IIIE), EIII (drug-metabolizing-enzyme-induced rats orally administered with mogroside III), and EIIIE (drug-metabolizing-enzyme-induced rats orally administered with mogroside IIIE) groups, respectively. The metabolite differences among these groups indicated that their minor structural differences are responsible for the significant differences in their metabolites, and the induction of drug-metabolizing enzymes significantly increased the number of their metabolites. These findings would improve our understanding of the in vivo processes of mogrosides III and IIIE as well as their interactions with other food bioactive components or drugs.