RESUMEN
Curcumin is a natural polyphenol derived from the turmeric plant (Curcuma longa) which exhibits numerous beneficial effects on different cell types. Inhibition of platelet activation by curcumin is well known, however molecular mechanisms of its action on platelets are not fully defined. In this study, we used laser diffraction method for analysis of platelet aggregation and Western blot for analysis of intracellular signaling mechanisms of curcumin effects on platelets. We identified two new molecular mechanisms involved in the inhibitory effects of curcumin on platelet activation. Firstly, curcumin by activation of adenosine A2A receptor stimulated protein kinase A activation and phosphorylation of Vasodilator-stimulated phosphoprotein. Secondly, we demonstrated that curcumin even at low doses, which did not inhibit platelet aggregation, potentiated inhibitory effect of ADP receptor P2Y12 antagonist cangrelor which partly could be explained by activation of adenosine A2A receptor.
Asunto(s)
Adenosina Monofosfato/análogos & derivados , Plaquetas/efectos de los fármacos , Moléculas de Adhesión Celular/genética , Curcumina/farmacología , Proteínas Quinasas Dependientes de AMP Cíclico/genética , Proteínas de Microfilamentos/genética , Fosfoproteínas/genética , Activación Plaquetaria/efectos de los fármacos , Receptor de Adenosina A2A/genética , Adenosina Difosfato/farmacología , Adenosina Monofosfato/farmacología , Plaquetas/citología , Plaquetas/metabolismo , Moléculas de Adhesión Celular/metabolismo , Curcuma/química , Curcumina/aislamiento & purificación , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Sinergismo Farmacológico , Regulación de la Expresión Génica , Humanos , Proteínas de Microfilamentos/metabolismo , Fosfoproteínas/metabolismo , Fosforilación , Extractos Vegetales/química , Inhibidores de Agregación Plaquetaria/farmacología , Cultivo Primario de Células , Antagonistas del Receptor Purinérgico P2Y/farmacología , Receptor de Adenosina A2A/metabolismo , Receptores Purinérgicos P2Y12/genética , Receptores Purinérgicos P2Y12/metabolismo , Transducción de SeñalRESUMEN
One new compound isoembinin 1 along with ten known compounds 2-11 were isolated from the terrestrial parts of Iris lactea Pall. All of the compound structures were determined through extensive 1D and 2D NMR experiments along with HR-ESIMS analysis and comparison with literature data. Because many flavonoids exert antiplatelet and antioxidant activity we tested the effects of the isolated flavone C-glycosides 1-9 on platelet activation and reactive oxygen species (ROS) production. Platelet reactivity was assessed by activation of αIIbß3 integrins activation and ROS production by DCF-DA fluorescence. For the analysis of whether protein kinase A or G are involved in the platelet inhibition, the activity of these kinases was analyzed by phosphorylation of their common substrate in platelets. In all experiments apigenin, which inhibit platelet activation was used as a positive control. All isolated flavone C-glycosides inhibited platelet αIIbß3 integrins activation with IC50 in the µM range, however this inhibitory effect was found to not be mediated through the prevention of ROS formation or by the activation of cyclic nucleotide pathways. Structure-activity comparison between apigenin and compounds 1-9 shows that the presence of C-glycoside and O-glycoside residues on the aglycone apigenin diminish the degree of platelet inhibition.