Antiplatelet flavonoids from seeds of Psoralea corylifolia

The MeOH extract of the seeds of Psoralea corylifolia L. was found to inhibit the aggregation of rabbit platelets induced by arachidonic acid, collagen, and platelet activating factor. Bioassay-directed fractionation led to the isolation of three flavonoids, isobavachalcone (1), neobavaiso-flavone (2), and bavachin (3). Compounds 1 and 2 inhibited platelet aggregation.