Characterization of Microbial Degradation Products of Steviol Glycosides
Gert Steurs,
Nico Moons,
Luc Van Meervelt,
Boudewijn Meesschaert,
Wim Michel De Borggraeve
Affiliations
Gert Steurs
Division of Molecular Design and Synthesis, Department of Chemistry, KU Leuven, Celestijnenlaan 200f, P.O. Box 2404, 3001 Leuven, Belgium
Nico Moons
Division of Molecular Design and Synthesis, Department of Chemistry, KU Leuven, Celestijnenlaan 200f, P.O. Box 2404, 3001 Leuven, Belgium
Luc Van Meervelt
Division of Biochemistry, Molecular and Structural Biology, Department of Chemistry, KU Leuven, Celestijnenlaan 200f, P.O. Box 2404, 3001 Leuven, Belgium
Boudewijn Meesschaert
Laboratory for Microbial and Biochemical Technology, Department of Microbial and Molecular Systems, KU Leuven Bruges Campus, Spoorwegstraat 12, P.O. Box 7913, 8200 Brugge, Belgium
Wim Michel De Borggraeve
Division of Molecular Design and Synthesis, Department of Chemistry, KU Leuven, Celestijnenlaan 200f, P.O. Box 2404, 3001 Leuven, Belgium
Steviol glycosides were subjected to bacteria present in a soil sample collected from a Stevia plantation in Paraguay. During the incubation experiments, next to the aglycon steviol, steviol degradation products were also formed. X-ray analysis and NMR methods in combination with chemical synthesis and GIAO NMR calculations were used to fully characterize the structure of these compounds as a tricyclic ketone and the corresponding reduced form. They were nicknamed monicanone and monicanol. The latter has the (S)-configuration at the alcohol site.
