Xanthone impairs platelet activation and thrombus formation.

Xanthone, a naturally occurring oxygenated heterocyclic compound from the Garcinia family with known anti-cancer, antimicrobial, antioxidant, anti-inflammatory, and antiviral properties, has an unclear role in platelet function. This study investigated its effects by incubating human platelets with xanthone at doses of 0, 5, 10, and 20 μM for 1 hour to analyze platelet aggregation, granule release, activation, receptor expression, spreading, and clot retraction, while also administering xanthone (10 mg/kg) to mice to evaluate its impact on hemostasis, arterial, and venous thrombosis. Our findings demonstrated that xanthone dose-dependently reduced platelet aggregation and granule release induced by collagen-related peptide (CRP) or thrombin without altering the surface expression of receptors αIIbβ3, GPIbα, and GPVI; it also significantly inhibited platelet spreading on collagen or fibrinogen, thrombin-mediated clot retraction, and decreased phosphorylation of c-Src and PLCγ2 in treated platelets. In vivo, xanthone-administered mice exhibited prolonged tail bleeding time and impaired arterial and venous thrombosis. Mechanistically, xanthone inhibited NF-κB activation, phosphorylation of ERK1/2 and p38, calcium mobilization, and platelet procoagulant activity. These findings indicate that xanthone impairs platelet activation and both arterial and venous thrombus formation, suggesting its potential as a novel agent for treating thrombotic or cardiovascular diseases.