title: Diuretic and potassium-sparing effect of isoquercitrin-an active flavonoid of Tropaeolum majus L.
abstract: OBJECTIVE
  Previous studies have shown that the extracts obtained from Tropaeolum majus L. exhibit pronounced diuretic effects supporting the ethnopharmacological use of this plant as diuretic. In the present work, phytochemical investigation, guided by bio-assay in spontaneously hypertensive rats (SHR), was carried out in order to identify the compounds responsible for diuretic action.
  
  
  METHODS
  Chromatographic fractionation of the hydroethanolic extract yielded an active fraction (TMLR) rich in isoquercitrin. TMLR (25-100mg/kg) and isoquercitrin (5-10mg/kg), as well the reference drug hydrochlorothiazide (10mg/kg) were orally administered in a single dose or daily for 7 days to SHR. The urine excretion rate, pH, density, conductivity and content of sodium (Na(+)) and potassium (K(+)) electrolytes were measured in the urine of saline-loaded animals.
  
  
  RESULTS
  The urinary excretion rate was dose-dependently increased in both TMLR and isoquercitrin groups, as well as Na(+). Despite the changes in urinary excretion of electrolytes, the plasmatic levels of Na(+) and K(+) had not been changed. In addition, we did not find any evidence of renal toxicity or other adverse effects in these animals, even after prolonged treatment with TMLR or isoquercitrin.
  
  
  CONCLUSIONS
  This research supports and extends the ethnomedicinal use of T. majus as diuretic. This activity seems to be associated to the presence of the flavonol isoquercitrin.
authors.affiliation: Department of Pharmacology, Universidade Paranaense, Umuarama, PR, Brazil.
authors.forename: Arquimedes
authors.initials: A
authors.lastname: Gasparotto Junior
authors.forename: Francielly Mourão
authors.initials: FM
authors.lastname: Gasparotto
authors.forename: Marcos Aurelio
authors.initials: MA
authors.lastname: Boffo
authors.forename: Emerson Luiz Botelho
authors.initials: EL
authors.lastname: Lourenço
authors.forename: Maria Élida Alves
authors.initials: MÉ
authors.lastname: Stefanello
authors.forename: Marcos José
authors.initials: MJ
authors.lastname: Salvador
authors.forename: José Eduardo
authors.initials: JE
authors.lastname: da Silva-Santos
authors.forename: Maria Consuelo Andrade
authors.initials: MC
authors.lastname: Marques
authors.forename: Cândida Aparecida Leite
authors.initials: CA
authors.lastname: Kassuya
mesh_terms: D000818:Animals; D004232:Diuretics / Q000302:isolation & purification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006852:Hydrochlorothiazide / Q000494:pharmacology; D006973:Hypertension / Q000097:blood / Q000188:drug therapy* / Q000652:urine; D008297:Male; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D018515:Plant Leaves; D011188:Potassium / Q000097:blood / Q000378:metabolism* / Q000652:urine; D011794:Quercetin / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D011918:Rats, Inbred SHR; D012964:Sodium / Q000097:blood / Q000652:urine; D032388:Tropaeolum / Q000737:chemistry*; D014554:Urination / Q000187:drug effects
chemical_list: D004232:Diuretics; D010936:Plant Extracts; D006852:Hydrochlorothiazide; C016527:isoquercitrin; D011794:Quercetin; D012964:Sodium; D011188:Potassium