title: Hypotensive and vasorelaxant effects of the procyanidin fraction from Guazuma ulmifolia bark in normotensive and hypertensive rats.
abstract: OBJECTIVE
  was to investigate the in vivo and in vitro cardiovascular activity of a procyanidin fraction (PCF) obtained from acetone extract of Guazuma ulmifolia bark which has traditionally been used as an antihypertensive agent.
  
  
  RESULTS
  10 mg/kg PCF doses orally administered to sugar-fed hypertensive rats decreased both the systolic arterial pressure and the heart rate, whereas the same doses intravenously administered induced arterial hypotension which was attenuated by NG-nitro-L-arginine methylester (L-NAME 31 mg/kg) pretreatment. In these experiments we employed carbachol as a positive control test. The PCF reduced the contraction induced by norepinephrine (1x10(-7) M) in isolated aortic rings of normotensive (IC50=35.3+/-12.4 ng/mL) and sugar-fed hypertensive (IC50=101.3+/-57.2 ng/mL) rats. This relaxant activity was inhibited by either vascular endothelium removal or L-NAME (30 microM) pretreatment, while indomethacin (10 microM) or atropine (10 microM) had no effect. Preliminary analysis of the PCF by HPLC-DAD-MS and FAB+ mass spectrometry allowed the detection of the main components such as the complex of procyanidin oligomers consisting mainly of tetramers and trimers.
  
  
  CONCLUSIONS
  Guazuma ulmifolia bark possesses long-lasting antihypertensive and vasorelaxing properties linked to the endothelium related factors, where nitric oxide is involved.
authors.affiliation: Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Apartado Postal No. 70-297, 04510 México, D.F., Mexico. gamagos@servidor.unam.mx
authors.forename: Gil Alfonso
authors.initials: GA
authors.lastname: Magos
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Mateos
authors.forename: Elna
authors.initials: E
authors.lastname: Páez
authors.forename: Gabriela
authors.initials: G
authors.lastname: Fernández
authors.forename: Carlos
authors.initials: C
authors.lastname: Lobato
authors.forename: Carmen
authors.initials: C
authors.lastname: Márquez
authors.forename: Raúl Guillermo
authors.initials: RG
authors.lastname: Enríquez
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D044946:Biflavonoids / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D002392:Catechin / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D019660:Malvaceae / Q000737:chemistry*; D009569:Nitric Oxide / Q000096:biosynthesis; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry*; D044945:Proanthocyanidins / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D044140:Receptor, Angiotensin, Type 1 / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D044946:Biflavonoids; D010936:Plant Extracts; D044945:Proanthocyanidins; D044140:Receptor, Angiotensin, Type 1; D009569:Nitric Oxide; C017674:procyanidin; D002392:Catechin