Lipase-catalyzed synthesis of laurate esters from puerarin and its β-D-fructofuranosyl-(2→6)-puerarin derivative

This study investigates the transesterification of isoflavones puerarin and beta-D-fructofuranosyl(2 -> 6)-puerarin to enhance their lipophilicity for specific pharmacological applications. The process achieved high yields (80-100%) in the isoflavones conversion when commercial lipases from Candida antarctica (CAL B) and Thermomyces lanuginosus ( TL IM) were used. The acylation patterns between CAL B and TL IM varied depending on the substrate; both enzymes yielded principally monoacylated products from puerarin and beta-D-fructofuranosyl-(2 -> 6)-puerarin. However, TL IM also produced di- and triacylated derivatives of beta-D-fructofuranosyl-(2 -> 6)-puerarin in substantial amounts. Structural characterization by NMR identified puerarin-6''- O-laurate and beta-D-fructofuranosyl-(2 -> 6)-puerarin-6'''-O-laurate as the primary products in CAL B and TL IM reactions. These acyl derivatives presented improved lipophilicity (Log P from -1.0 - 0.16 to 3.26 - 3.58) and antioxidant activity (67.2-97.3 to 102.5-131.4 mu M TE/mmol). Therefore, these compounds have potential pharmacological applications.