Coumarin Derivatives Inhibit ADP-Induced Platelet Activation and Aggregation

Figures

• 

  Figure 1. Chemical structure of the different assayed coumarin derivatives.

• 

  Figure 2. Effects of coumarin derivatives on ADP−induced platelet aggregation. Human PRP was treated with DMSO (control) or 10 ppm of coumarin derivates (A) or the indicated concentrations of coumarin derivatives (B) for 30 min, followed by addition of 10 μM ADP, and aggregation was analyzed using an aggregometer for 6 min. The data are presented as the aggregation ratio relative to control group treated with ADP only (n = 3). * p < 0.05 compared with the control group treated with ADP only.

• 

  Figure 3. Effects of coumarin derivatives on the expression of glycoproteins on human platelet membranes. Human blood was treated with 10 ppm of coumarin derivatives for 30 min, followed by the addition of 20 μM ADP for 30 min. The expression of GPIIIa and active form of GPIIb/IIIa on the membrane was analyzed using flow cytometry. The flow data for GPIIIa and GPIIb/IIIa on platelet membranes from one of three independent experiments (n = 3) (A). Experimental results are summarized as MFI values of platelet membrane (B). * p < 0.05 compared with the control group. # p < 0.05 compared with whole blood stimulated with ADP alone.

• 

  Figure 4. Effects of coumarin derivatives on the release of AA and TXA2 from human platelets. Human PRP was treated with 10 ppm of coumarin derivatives for 1 h. Purified plates were isolated, and 10 μM ADP and 3 μM fibrinogen were added for 30 min. Contents of AA (A) and TXA2 (B) were analyzed using an enzyme immunoassay (n = 3). * p < 0.05 compared with the control group. # p value < 0.05 for PRP treated with indicated compound followed by ADP stimulation compared with PRP stimulated with ADP alone.

• 

  Figure 5. Effects of coumarin derivatives on calcium and cAMP production in human platelets. Human PRP was treated with 10 ppm of coumarin derivatives for 1 h, and Fura-2AM reagent was added. Purified plate isolates were treated with 10 μM ADP, and calcium concentration was monitored in an EIA reader. Data are presented as the fold change relative to control group not treated with ADP (A). * p < 0.05 compared with control group. Human PRP was treated with 10 ppm of coumarin derivatives for 1 h, and isolated platelets were treated with 10 μM forskolin and 10 μM ADP for 5 min. Platelet lysates were prepared, and cAMP levels were measured using an enzyme immunoassay (n = 3). * p < 0.05 between two groups. # p < 0.05 for PRP treatment of indicated compound followed by forskolin and ADP stimulation compared with PRP stimulated with forskolin and ADP alone (B).