title: Vasorelaxant and hypotensive effects of the extract and the isolated flavonoid rutin obtained from Polygala paniculata L.
abstract: OBJECTIVE
  This study aimed to investigate the in-vitro and in-vivo cardiovascular effects of the crude hydroalcoholic extract from Polygala paniculata (HEPP) in rats.
  
  
  METHODS
  The procedures were performed on aortic rings and on normotensive anaesthetized rats.
  
  
  RESULTS
  When tested in endothelium-intact aorta rings, HEPP (30-1000 µg/ml) produced a significant non-concentration-dependent relaxing effect (∼40%), which was completely prevented by incubation with L-NAME (nitric oxide synthase inhibitor), ODQ (soluble guanylate cyclase inhibitor) and partially inhibited by tetraethylammonium (TEA; a non-selective potassium channel blocker) and charybdotoxin (a large- and intermediate-conductance calcium-activated potassium channel blocker). In contrast, atropine (a muscarinic receptor antagonist) or pyrilamine(a histamine H1 receptor antagonist) had no effect. Furthermore, oral administration of HEPP (30-300 mg/kg) in anaesthetized rats caused a dose-dependent and sustained hypotensive action. This effect was unchanged by atropine or TEA, but was strongly reduced in rats continuously infused with L-NAME or methylene blue. Moreover, rutin (1-3 mg/kg) administered by an intravenous route also caused a dose-dependent hypotensive effect in rats.
  
  
  CONCLUSIONS
  Our results demonstrated that the extract obtained from P. paniculata induces potent hypotensive and vasorelaxant effects that are dependent on the nitric oxide/guanylate cyclase pathway. These effects could be related, at least in part, to the rutin contents in this extract.
authors.affiliation: Department of Pharmacology, Center of Biological Sciences, Federal University of Paraná, Curitiba, Brazil.
authors.forename: Fernanda da Rocha
authors.initials: Fda R
authors.lastname: Lapa
authors.forename: Kelly Cristina
authors.initials: KC
authors.lastname: Soares
authors.forename: Yanna Dantas
authors.initials: YD
authors.lastname: Rattmann
authors.forename: Sandra
authors.initials: S
authors.lastname: Crestani
authors.forename: Fabiana Cristina
authors.initials: FC
authors.lastname: Missau
authors.forename: Moacir Geraldo
authors.initials: MG
authors.lastname: Pizzolatti
authors.forename: Maria Consuelo Andrade
authors.initials: MC
authors.lastname: Marques
authors.forename: Lia
authors.initials: L
authors.lastname: Rieck
authors.forename: Adair Roberto Soares
authors.initials: AR
authors.lastname: Santos
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001011:Aorta / Q000187:drug effects / Q000502:physiology; D001285:Atropine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors; D008297:Male; D008751:Methylene Blue / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology*; D031801:Polygala / Q000737:chemistry*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011738:Pyrilamine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012431:Rutin / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D000959:Antihypertensive Agents; D004791:Enzyme Inhibitors; D010936:Plant Extracts; D026902:Potassium Channel Blockers; D014665:Vasodilator Agents; D012431:Rutin; D001285:Atropine; D006162:Guanylate Cyclase; D011738:Pyrilamine; D008751:Methylene Blue; D019331:NG-Nitroarginine Methyl Ester