Fast and reproducible chemical synthesis of zearalenone-14-β,D-glucuronide

The Fusarium mycotoxin zearalenone (ZEA) is mainly converted to the conjugate zearalenone-14-beta,D-glucuronide (ZEA-14-GlcA) during phase II detoxification in humans and animals. This metabolite - previously described as zearalenone-4-O-beta, D-glucuronide - is excreted via urine and could therefore serve as possible biomarker for ZEA exposure to estimate its intake. Direct determination of this substance is limited by the availability of a reference substance. So far, only the production of small amounts by enzymatic synthesis has been described. In this work, a fast and reproducible protocol for the chemical synthesis of ZEA-14-GlcA was developed, using substituted beta-resorcylic acid esters as mycotoxin mimics and different glucuronyl donors for optimising the glycosylation (Konigs-Knorr, trifluoroacetimidate method) and the deprotection step. This cost-effective procedure should be easily reproducible in other labs using standard equipment and common reagents.