Anti-platelet effects of flavonoids and flavonoid-glycosides from Sophora japonica

A methanol extract of Sophora japonica was subjected to anti-platelet activity guided fractionation affording the isolation of four flavonoids and six flavonoid-glycosides: biochanin A ( 1 ), irisolidone ( 2 ), genistein ( 3 ), sissotrin ( 4 ), sophorabioside ( 5 ), genistin ( 6 ), tectoridin ( 7 ), apigenin ( 8 ), quercitrin ( 9 ), and rutin ( 10 ). The structure of each compound was determined by a variety of spectroscopic methods. Among the compounds, 1, 3 , and 7 showed ∼2.5–6.5 fold greater inhibitory effects on arachidonic acid (AA) and U46619 induced platelet aggregation (IC 50 : 19.9 and 99.8 μM; 20.3 and 53.8 μM; 25.9 and 123.4 μM, respectively) than acetylsalicylic acid (ASA, IC 50 : 63.0 and 350.0 μM). Compound 2 was an ∼22–40 fold stronger inhibitor than ASA on AA and U46619 induced aggregation (IC 50 : 1.6 and 15.6 μM, respectively).