Inhibitory activity of ginsenosides isolated from processed ginseng on platelet aggregation

Seven ginsenosides, namely Rg(6) (1), F-4 (2), Rk(3) (3), Rh-4 (4), Rs(3) (5), Rs(4) (6) and Rs(5) (7) isolated from processed ginseng were evaluated for their effects on platelet aggregation induced by adenosine diphosphate (ADP), collagen, arachidonic acid (AA) and U46619 (thromboxane A(2) mimetic drug). Ginsenosides Rg(6), F-4 and Rk(3) showed inhibitory activity (IC50=76 mu M, 114 mu M and 128 mu M, respectively) on AA-induced platelet aggregation. The corresponding IC50 values were comparable to that of acetylsalicylic acid (ASA) (63 mu M). Compared to ASA (IC50=468 mu M) ginsenosides Rg(6), F-4, Rk(3) and Rh-4 were found to be more inhibitive (IC50=286 mu M, 87 mu M, 187 mu M and 119 mu M, respectively) against U46619-induced aggregation. On the other hand, most of the ginsenosides (Rg(6), F-4, Rh-4, Rs(3), Rs(5)) showed negligible effects on ADP and collagen-induced platelet aggregation. The acetylated ginsenosides (Rs(3), Rs(4) and Rs(5)) had only mild effects on aggregation induced by four stimulators.