Simultaneous preparation of α/β-zearalenol glucosides and glucuronides
Hannes Mikula1, Julia Weber, Stefan Lexmüller
1Institute of Applied Synthetic Chemistry, Vienna University of Technology, Vienna 1060, Austria. hannes.mikula@tuwien.ac.at
Abstract:
An improved and reproducible procedure for the preparation of four different glycosides of the mycotoxins α- and β-zearalenol (α,β-ZEL), both metabolites of the Fusarium toxin zearalenone (ZEN), is reported. These conjugated or masked mycotoxins are formed during phase II metabolism in plants (glucosides) or animals and humans (glucuronides). Improved regioselective Königs-Knorr glucuronidation was applied to ZEN followed by reduction of the keto group of the mycotoxin, leading to α- and β-configuration of ZEL and also to a partial reduction of the glucuronic acid methyl ester to obtain the corresponding glucosides. After deprotection of the sugar moiety, α- and β-zearalenol-14-β,D-glucuronide as well as the corresponding glucosides were isolated at once using preparative HPLC. The reduction step was studied under different reaction conditions to finally develop an optimized and also tunable procedure for the first simultaneous preparation of both, glucosides and glucuronides of a xenobiotic substance in reasonable amounts to be used as reference materials for bioanalytical and toxicological investigations.
Related Concept Videos
Phase II Reactions: Glucuronidation
Drug Metabolism: Phase II Reactions
Phase II Reactions: Sulfation and Conjugation with α-Amino Acids
Dehydration of Aldols to Enals: Base-Catalyzed Aldol Condensation
Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis
E2 Reaction: Stereochemistry and Regiochemistry
When a substrate with two different β hydrogens undergoes an E2 elimination, the presence of a strong base can yield two regioisomeric alkenes. The more-substituted alkene is the major product and...


