title: Preparative enzymatic synthesis of glucuronides of zearalenone and five of its metabolites.
abstract: The resorcylic acid lactones zearalenone ( 1), alpha-zearalenol ( 2), beta-zearalenol ( 3), alpha-zearalanol (zeranol) ( 4), beta-zearalanol (taleranol) ( 5), and zearalanone ( 6) were converted to their glucuronides on a preparative scale in good yields. Reactions were conducted with bovine uridine 5'-diphosphoglucuronyl transferase (UDPGT) as catalyst and uridine 5'-diphosphoglucuronic acid (UDPGA) as cofactor. The glucuronides were isolated by column chromatography and characterized by NMR spectroscopy and mass spectrometry. Although the principal products were 4- O-glucuronides (i.e., linkage through a phenolic hydroxyl), significant quantities of the 6'- O-glucuronides (i.e., linkage through the aliphatic hydroxyl) of alcohols 2, 4, and 5 were also isolated. In the case of 3, the 2- O-glucuronide was isolated as the minor product. Overall isolated yields of glucuronides, performed on a 20-50 mg scale, were typically ca. 80% based on the resorcylic acid lactone starting material. LC-UV-MS (2) analysis of purified specimens revealed MS (2) fragmentations useful for defining the point of attachment of the glucuronide moiety to the zearalenone nucleus.
authors.affiliation: HortResearch Ltd., Ruakura Research Centre, Private Bag 3123, Hamilton, New Zealand.
authors.forename: David E
authors.initials: DE
authors.lastname: Stevenson
authors.forename: Richard P
authors.initials: RP
authors.lastname: Hansen
authors.forename: Jared I
authors.initials: JI
authors.lastname: Loader
authors.forename: Dwayne J
authors.initials: DJ
authors.lastname: Jensen
authors.forename: Janine M
authors.initials: JM
authors.lastname: Cooney
authors.forename: Alistair L
authors.initials: AL
authors.lastname: Wilkins
authors.forename: Christopher O
authors.initials: CO
authors.lastname: Miles
mesh_terms: D000818:Animals; D002417:Cattle; D020719:Glucuronides / Q000096:biosynthesis* / Q000737:chemistry; D014453:Glucuronosyltransferase / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015025:Zearalenone / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism
chemical_list: D020719:Glucuronides; D015025:Zearalenone; D014453:Glucuronosyltransferase