title: The Operculina macrocarpa (l.) urb. (jalapa) tincture modulates human blood platelet aggregation.
abstract: BACKGROUND
  Operculina macrocarpa is an ornamental climbing plant of the Northeastern Brazil extensively used in traditional medicine as depurative of the blood and for the treatment of thrombosis. To investigate the antiplatelet and anticoagulant potential of Operculina macrocarpa and to determine the possible mechanisms of action.
  
  
  METHODS
  The Operculina macrocarpa tincture (OMT) was characterized by the polyphenol content and chromatographic profile established by HPLC with detection and quantification of three phenol acids (caffeic, clorogenic and gallic acids). The human platelet aggregation was induced in vitro by the agonists ADP, collagen, thrombin, epinephrine or arachidonic acid, and the antiplatelet effect of OMT was evaluated in the presence or absence of aspirin (a nonselective inhibitor of cyclooxygenase), pentoxifylline (a phosphodiesterase inhibitor), ticlopidine (a P2Y12 purinoceptor antagonist) or ODQ (a selective inhibitor of guanilate cyclase). The effect of OMT on the partial thromboplastin time, prothrombin time and bleeding time were investigated on human or rat plasma.
  
  
  RESULTS
  The strongest antiplatelet effect of OMT (50-400 µg/mL) was observed on the ADP- induced aggregation with inhibitions up to 55%, while among others agonists (epinephrine, collagen, thrombin and arachidonic acid) maximal inhibitions reached by OMT (200 µg/mL) were on platelet aggregation induced by collagen (18%) or epinephrine (20%). The antiplatelet effect of OMT (400 µg/mL) was comparable to aspirin, a nonspecific inhibitor of cyclooxygenase. The ticlopidine and pentoxifylline increased 5.1 and 3.8 fold the inhibitory effect of OMT on ADP-induced platelet aggregation, respectively. On the other hand, l-arginine, ODQ and aspirin showed a slightly or no effect on antiplatelet effect of OMT. The bleeding time in rats was significantly increased by OMT, but the tincture did not interfere on the activated partial thromboplastin or prothrombin time in human plasma.
  
  
  CONCLUSIONS
  This study showed that the tincture of Operculina macrocarpa has antiplatelet effect that cannot be attributed to a single biochemical mechanism and at least part of it cannot be related to the OMT inhibition of P2Y12 purinergic receptors.
authors.affiliation: Programa de Pós-Graduação em Farmacologia, Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Brazil.
authors.forename: Taiana Magalhães
authors.initials: TM
authors.lastname: Pierdoná
authors.affiliation: Centro de Estudos Farmacêuticos e Cosméticos (CEFAC), Departamento de Farmácia, Faculdade de Farmácia, Odontologia e Enfermagem, Universidade Federal do Ceará 60431-327, Brazil.
authors.forename: Nathalia Rocha
authors.initials: NR
authors.lastname: Lima
authors.affiliation: Centro de Estudos Farmacêuticos e Cosméticos (CEFAC), Departamento de Farmácia, Faculdade de Farmácia, Odontologia e Enfermagem, Universidade Federal do Ceará 60431-327, Brazil.
authors.forename: Raony Cássio Millet
authors.initials: RC
authors.lastname: Rodrigues
authors.affiliation: Centro de Estudos Farmacêuticos e Cosméticos (CEFAC), Departamento de Farmácia, Faculdade de Farmácia, Odontologia e Enfermagem, Universidade Federal do Ceará 60431-327, Brazil.
authors.forename: Jonas Pires
authors.initials: JP
authors.lastname: Teixeira
authors.affiliation: Centro de Estudos Farmacêuticos e Cosméticos (CEFAC), Departamento de Farmácia, Faculdade de Farmácia, Odontologia e Enfermagem, Universidade Federal do Ceará 60431-327, Brazil.
authors.forename: Romélia Pinheiro
authors.initials: RP
authors.lastname: Gonçalves
authors.affiliation: Centro de Estudos Farmacêuticos e Cosméticos (CEFAC), Departamento de Farmácia, Faculdade de Farmácia, Odontologia e Enfermagem, Universidade Federal do Ceará 60431-327, Brazil.
authors.forename: Juvenia Bezerra
authors.initials: JB
authors.lastname: Fontenele
authors.affiliation: Programa de Pós-Graduação em Farmacologia, Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Brazil.
authors.forename: Silvânia Maria Mendes
authors.initials: SM
authors.lastname: Vasconcelos
authors.affiliation: Programa de Pós-Graduação em Farmacologia, Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Brazil.
authors.forename: Glauce Socorro
authors.initials: GS
authors.lastname: de Barros Viana
authors.affiliation: Programa de Pós-Graduação em Farmacologia, Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Brazil; Centro de Estudos Farmacêuticos e Cosméticos (CEFAC), Departamento de Farmácia, Faculdade de Farmácia, Odontologia e Enfermagem, Universidade Federal do Ceará 60431-327, Brazil. Electronic address: kalyne@ufc.br.
authors.forename: Luzia Kalyne Almeida Moreira
authors.initials: LK
authors.lastname: Leal
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000187:drug effects*; D027722:Convolvulaceae / Q000737:chemistry*; D006801:Humans; D008297:Male; D008519:Medicine, Traditional; D051379:Mice; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats
chemical_list: D010936:Plant Extracts; D010975:Platelet Aggregation Inhibitors
keywords: Anticoagulant; Antiplatelet; Convolvulaceae; Operculina macrocarpa