Comparative In vitro metabolism of purified mogrosides derived from monk fruit extracts.

Mogrosides are the primary components responsible for the sweet taste of Monk fruit which is derived from Siraitia grosvenorii (Swingle), a herbaceous plant native to southern China. Many mogrosides have been identified from Monk fruit extract, but the major sweetness component of Monk fruit by mass is mogroside V, comprising up to 0.5% of the dried fruit weight. Recent pharmacokinetic studies indicate that the parent mogrosides undergo minimal systemic absorption following ingestion and hydrolysis by digestive enzymes and/or intestinal flora and are excreted as mogrol (i.e., the aglycone) and its mono- and diglucosides. The objective of this study was to demonstrate whether individual mogrosides, are metabolized to a common and terminal deglycosylated metabolite, mogrol. An in vitro assay was conducted with pooled human male and female intestinal fecal homogenates (HFH) using mogrosides IIIe, mogroside V, siamenoside I, and isomogroside V at two concentrations over a 48 h period. The results show that various mogrosides that differ in the linkages and number of glucose units attached to a common cucurbitane backbone, share a common metabolic fate, and are metabolized within 24 h to mogrol. Aside from an apparent difference in the initial rate of deglycosylation between mogrosides at higher concentrations, no apparent difference in the rate of deglycosylation was observed between the male and female HFH. Given the similar structures of these mogrosides and a shared metabolic fate to mogrol, the study provides support for a reasonably conservative approach to assess safety based on bridging safety data from an individual mogroside (i.e., Mogroside V) to other mogrosides, and the establishment of a group Acceptable Daily Intake (ADI), rather than individual ADI's for mogrosides.

Steviol glycosides in purified stevia leaf extract sharing the same metabolic fate.

The safety of steviol glycosides is based on data available on several individual steviol glycosides and on the terminal absorbed metabolite, steviol. Many more steviol glycosides have been identified, but are not yet included in regulatory assessments. Demonstration that these glycosides share the same metabolic fate would indicate applicability of the same regulatory paradigm. In vitro incubation assays with pooled human fecal homogenates, using rebaudiosides A, B, C, D, E, F and M, as well as steviolbioside and dulcoside A, at two concentrations over 24-48 h, were conducted to assess the metabolic fate of various steviol glycoside classes and to demonstrate that likely all steviol glycosides are metabolized to steviol. The data show that glycosidic side chains containing glucose, rhamnose, xylose, fructose and deoxy-glucose, including combinations of α(1-2), ß-1, ß(1-2), ß(1-3), and ß(1-6) linkages, were degraded to steviol mostly within 24 h. Given a common metabolite structure and a shared metabolic fate, safety data available for individual steviol glycosides can be used to support safety of purified steviol glycosides in general. Therefore, steviol glycosides specifications adopted by the regulatory authorities should include all steviol glycosides belonging to the five groups of steviol glycosides and a group acceptable daily intake established.