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