Antiplatelet aggregation activity of compounds isolated from guttiferae species in human whole blood

Twenty compounds isolated from Calophyllum inophyllum L., C. inophylloides King, Garcinia opaca King, G. bancana Miq., and G. parvifolia Miq. (Guttiferae) were evaluated for their ability to inhibit platelet aggregation in human whole blood induced by arachidonic acid (AA), collagen, and adenosine diphosphate (ADP). The compounds inhibited platelet aggregation in a dose-dependent manner. Among the compounds tested, 2-(3-methylbut-2-enyl)-1,3,5-trihydroxyxanthone and 2-(3-methylbut-2-enyl)-1,3,5,6- tetrahydroxyxanthone showed strong inhibitory activity on platelet aggregation induced by AA with IC50 values of 115.9 and 113.0µM, respectively. Rubraxanthone showed inhibitory activity against aggregation caused by the three inducers, and was the most effective antiplatelet compound against collagen-induced platelet aggregation with an IC50 value of 47.0µM. Macluraxanthone, GB-1a, pyranoamentoflavone, and a neoflavonoid showed selective inhibitory activity on platelet aggregation induced by ADP