Laccase-Catalyzed Dimerization of Piceid, a Resveratrol Glucoside, and its Further Enzymatic Elaboration

The laccase-catalyzed oxidation of piceid, the 3-beta-D-glucopyranosyl derivative of the stilbenic phytoalexin resveratrol, allowed isolation of the corresponding beta-5 like trans-dehydrodimer in good yield (45%) avoiding chromatography. This compound was then submitted to the action of a small library of commercially available hydrolases. While the cellulase from Trichoderma viride was able to fully hydrolyze the diglycosylated dimer to give the corresponding beta-5 like trans-dehydrodimer of resveratrol, the beta-glucosidase from almonds allowed the isolation of a monoglycosylated intermediate in reasonable yield. The diastereoisomers and the enantiomers of the isolated dimeric products were separated using a semi-preparative chiral column. The basic antioxidant properties of these new dimers have been determined.