Potential target-related proteins in rabbit platelets treated with active monomers dehydrocorydaline and canadine from Rhizoma corydalis.

Background: Dehydrocorydaline (DHC) and canadine (THB) are two active alkaloid compounds in Corydalis yanhusuo (Y.H. Chou & Chun C. Hsu) W.T. Wang ex Z.Y. Su & C.Y. Wu (Papaveraceae) (Rhizoma Corydalis). DHC and THC were previously shown to exert anti-platelet aggregation effect dose-dependently, but their exact mechanisms had not yet been addressed. Therefore, it is essential to study the mechanisms of DHC and THB affecting on platelet's function.

Purpose: To investigate the anti-platelet effects and corresponding signal cascades of DHC and THB on platelet aggregation.

Methods: Firstly, in vitro anti-platelet aggregation of DHC and THB induced by different agonists including thrombin (THR), adenosine diphosphate (ADP) and arachidonic acid (AA) were determined through turbidimetry method. Then the possible target-related platelet proteins after treated with DHC/THB were separated and identified by two dimensional gel electrophoresis (2-DE) and MALDI-TOF-MS/MS analysis, respectively. Finally, the signal cascades network induced by DHC/THB were predicted through functional analysis of these proteins along with the determination of platelet DAG concentration.

Results: The platelet aggregation stimulated by THR, ADP and AA were inhibited by DHC and THB dose-dependently to a certain degree. Meanwhile, DHC and THB had the strongest effect on ADP- and THR-induced platelet aggregation respectively. In addition, treatment of these two compounds caused regulations of about sixty proteins in platelet, including cytoskeleton proteins, cell signaling proteins, proteins related to material energy metabolism, etc. CONCLUSIONS: Using proteomic analysis combined with platelet aggregation test and ELISA, this study was successful in exploring the possible mechanisms of DHC/THB on platelet aggregation. DHC might inhibit platelet aggregation by a mechanism involving the ADP receptors P2Y1 and P2Y12, and the effect of THB on platelet function may be related to its binding to THR receptor PAR1 for mediated Gi signaling pathway. These results provide fundamental information for the anti-thrombotic effect of RC.