Figure 1. Concentration-dependent inhibitory effect of honokiol in agonist-stimulated platelet aggregation.

Washed human platelets (3.6 × 10⁸ cells/ml) were preincubated with honokiol (0.1–5 μM) (A, chemical structure) or a solvent control (0.5% DMSO), and subsequently treated with 1 μg/ml of collagen (○), 0.05 IU/ml of thrombin (◇), 1 μM U46619 (□), or 60 μM arachidonic acid (∇) to trigger platelet aggregation for 6 min (B–D). For the other experiment, platelet-rich plasmas were preincubated with honokiol (1–10 μM), subsequently treated with 20 μM ADP to trigger platelet aggregation for 6 min (C). Statistical data (D) are presented as the means ± SEM (n = 4).