Two-step enzymatic modification of solid-supported bergenin in aqueous and organic media

The natural flavonoid bergenin was directly immobilized onto carboxylic acid-functionalized controlled pore glass (carboxy-CPG) at 95% yield. Immobilized bergenin was brominated via chloroperoxidase in aqueous solution and then transesterified with vinyl butyrate in diisopropyl ether by subtilisin carslberg (SC) extracted into the organic solvent via ion-pairing. Enzymatic cleavage of 7-bromo-4-butyrylbergenin from carboxy-CPG (9.6% final yield) was accomplished using lipase B (LipB) in an aqueous/organic mixture (90/10 v/v of water/acetonitrile), demonstrating the feasibility of solid-phase biocatalysis of a natural product in aqueous and non-aqueous media.