Synthesis of phospholipase A2 inhibitory biflavonoids

A series of C-C Biflavones was designed to investigate the relationship between structural array of different flavone-flavone subunit linkage and the inhibitory activity against Phospholipase A2 (PLA2). Among six classes of C-C Biflavones designed, four classes of C-C Biflavones, which have flavone-flavone subunit linkages at A ring-A ring, A ring-B ring, B ring-B ring, and B ring-C ring, were synthesized. The synthetic Biflavones exhibited somewhat different inhibitory activities against sPLA2-IIA. Among them, the biflavone a having a C-C 4'-4' linkage showed comparable inhibitory activity with that of the natural biflavonoid, ochnaflavone, and 7-fold stronger activity than that of amentoflavone. Further chemical modification is being carried out in order to obtain the chemically optimized biflavonoids.