Polyphenol-Rich Oenanthe javanica as a Cardioprotective Functional Food Candidate Exhibiting Antiplatelet Activity via Suppression of Ca2+ Mobilization and Thromboxane A2 Production

Polyphenol-rich Oenanthe javanica (Blume) DC. is widely consumed in Asia but its impact on platelet activation, a cause of cardiovascular disease (CVD), is unclear. Collagen-driven platelet activation requires intracellular Ca2+ mobilization and thromboxane A2 (TXA2) production—rational targets for CVD prevention. A hot water extract of O. javanica (OJWE) was profiled by HPLC and tested on collagen-stimulated washed human platelets. Aggregation, Fura-2 [Ca2+]i, and TXB2 were measured, including combinations with verapamil, aspirin, caffeic acid (CA), and chlorogenic acid (CGA). Coagulation (PT/APTT) and ex vivo effects in Sprague–Dawley rats given OJWE (1 or 5 mg day−1, 30 days) were also evaluated. OJWE dose-dependently inhibited collagen-induced aggregation in a Ca2+-dependent manner, synergizing with verapamil, and suppressed [Ca2+]i mobilization and TXA2 production. CA and CGA synergistically enhanced aspirin-mediated COX-1 inhibition. PT/APTT were unaffected in vitro and ex vivo. Dietary OJWE modestly but significantly reduced rat platelet aggregation without altering coagulation. OJWE attenuates platelet activation by selectively targeting Ca2+ mobilization and TXA2 biosynthesis without compromising hemostasis, supporting O. javanica as a functional food with cardiovascular potential at dietary intake.