title: Potent antihypertensive effect of Hancornia speciosa leaves extract.
abstract: BACKGROUND
  Hancornia speciosa Gomes is an herb traditionally used in Brazil for blood pressure control.
  
  
  OBJECTIVE
  The present work investigated the antihypertensive effect of an extract from Hancornia speciosa leaves (SFH) and analyzed its underlying mechanisms of action.
  
  
  METHODS
  Hypertension was induced in mice by surgical removal of a kidney and by subcutaneous administration of a pellet with deoxycorticosterone. Vasodilatation was measured in mesenteric arteries with a wire myograph. Nitrites were measured by fluorescence with 2,3-diaminonaphthalene and H2O2 was measured with carbon microsensors.
  
  
  RESULTS
  SFH (0.03, 0.1 or 1 mg/kg; po) induced a dose-dependent, long-lasting reduction in the systolic blood pressure in conscious DOCA-salt hypertensive mice (DOCA). Administration of SFH produced a significant increase in the plasmatic level of nitrites. The systemic inhibition of nitric oxide synthase by L-NAME (20 mg/kg) reduced its antihypertensive effect. SFH also induced a concentration-dependent vasodilatation of mesenteric resistance arteries contracted with phenylephrine, which was more potent in arteries from DOCA mice. Removal of the endothelium or pretreatment with L-NAME or catalase reduced the vasodilator response for SFH. The nitrite production induced by SFH was significantly bigger in mesenteric arteries from DOCA than in SHAM mice. However, the production of H2O2 induced by SFH was twice higher in DOCA mice.
  
  
  CONCLUSIONS
  Altogether, our results point to an antihypertensive effect of SFH due to a reduction in peripheral resistance through the production of NO and by a mechanism involving an increased production of H2O2 in the mesenteric arteries from hypertensive mice. These findings are further evidence to support the use of Hancornia speciosa by traditional medicine as an antihypertensive drug.
authors.affiliation: Department of Pharmacology, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil ; Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Grazielle C
authors.initials: GC
authors.lastname: Silva
authors.affiliation: Department of Pharmaceutical Sciences, Faculty of Pharmacy, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Fernão C
authors.initials: FC
authors.lastname: Braga
authors.affiliation: Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Virgínia S
authors.initials: VS
authors.lastname: Lemos
authors.affiliation: Department of Pharmacology, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil . Electronic address: sfcortes@icb.ufmg.br.
authors.forename: Steyner F
authors.initials: SF
authors.lastname: Cortes
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D029062:Apocynaceae / Q000737:chemistry*; D001794:Blood Pressure / Q000187:drug effects; D001938:Brazil; D003900:Desoxycorticosterone; D006861:Hydrogen Peroxide / Q000378:metabolism; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects; D051379:Mice; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009573:Nitrites / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D000959:Antihypertensive Agents; D009573:Nitrites; D010936:Plant Extracts; D014665:Vasodilator Agents; D003900:Desoxycorticosterone; D006861:Hydrogen Peroxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester
keywords: Antihypertensive effect; Hancornia speciosa Gomes; Hydrogen peroxide; Nitric oxide; Resistance arteries