Embelin is a
quinone derivative and found in the fruits of Embelia ribes Burm.f.
Embelin has been identified as a small molecular inhibitor of X-chromosome-linked
inhibitor of apoptosis proteins, and has multiple biological activities, including antioxidation, anti-
inflammation, and antitumor effects. However, the effect of
embelin in platelets remains unclear. Thus, this study investigated the antiplatelet mechanism of
embelin. Our data revealed that
embelin could inhibit platelet aggregation induced by various agonists, including the
protein kinase C (PKC) activator
phorbol 12,13-dibutyrate (PDBu).
Embelin, as well as the PKC inhibitor
Ro 31-8220, markedly reduced PDBu-mediated phosphorylation of the PKC substrate, suggesting that
embelin may be a PKC inhibitor for platelets.
Embelin could block PKC downstream signaling and events, including the inhibition of
protein kinase B and
mitogen-activated protein kinase activation, granule release, and
glycoprotein IIbIIIa activation. Moreover,
embelin could delay
thrombus formation in the mesenteric microvessels of mice, but did not significantly affect the tail bleeding time. In conclusion, we demonstrated that
embelin is a PKC inhibitor and possesses antiplatelet and antithrombotic effects. The further analysis is necessary to more accurately determine clinical therapeutic potential of
embelin in all clinical thromboembolic events with disturbance of thrombocyte function.