title: Inhibitory effect of Scutia buxifolia extracts, fractions, and ursolic acid on Na(+), K(+)-ATPase activity in vitro in membranes purified from rat hearts.
abstract: BACKGROUND
  Scutia buxifolia is a tree native to South America and is used as a cardiotonic agent; however, this property has not been associated with a clear mechanism or a specific compound.
  
  
  OBJECTIVE
  Given the importance of Na(+),K(+)-ATPase as a drug target in the treatment of heart failure, this study aimed to investigate the possible inhibitory effect of S. buxifolia crude extract and fractions (dichloromethane, ethyl acetate, and butanolic fractions), and identified compounds with effects on the activity of Na(+),K(+)-ATPase in vitro.
  
  
  METHODS
  First, we characterized the crude extract and fractions by high-performance liquid chromatography, and then monitored their effects on the activity of Na(+),K(+)-ATPase obtained from heart muscle and brain membranes of adult male Wistar rats.
  
  
  RESULTS
  We identified gallic acid, chlorogenic acid, caffeic acid, rutin, quercitrin, quercetin, and ursolic acid in S. buxifolia stem bark and leaves; quercitrin and ursolic acid were the main compounds in the ethyl acetate and dichloromethane fractions from leaves and stem bark. The crude extract (3 and 30mg/ml), and the ethyl acetate and dichloromethane fractions (0.1 and 1mg/ml) of both the stem bark and leaves inhibited Na(+),K(+)-ATPase activity in heart and brain samples. We found that, of the identified compounds, only ursolic acid (0.1mg/ml) was able to diminish Na(+), K(+)-ATPase activity in heart and brain samples.
  
  
  CONCLUSIONS
  These data indicated that the cardiotonic effects of S. buxifolia may be due to the inhibition of Na(+),K(+)-ATPase activity in heart muscle, supporting the popular use of this plant as a treatment for heart failure.
authors.affiliation: Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria (UFSM), 97105-900 Santa Maria, RS, Brazil.
authors.forename: Fabiano B
authors.initials: FB
authors.lastname: Carvalho
authors.affiliation: Programa de Pós-graduação em Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Santa Maria (UFSM), 97105-900 Santa Maria, RS, Brazil.
authors.forename: Aline A
authors.initials: AA
authors.lastname: Boligon
authors.affiliation: Programa de Pós-graduação em Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Santa Maria (UFSM), 97105-900 Santa Maria, RS, Brazil.
authors.forename: Margareth L
authors.initials: ML
authors.lastname: Athayde
authors.affiliation: Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria (UFSM), 97105-900 Santa Maria, RS, Brazil.
authors.forename: Maribel A
authors.initials: MA
authors.lastname: Rubin
authors.affiliation: Programa de Pós-graduação em Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC), 88049-900 Florianópolis, SC, Brazil.
authors.forename: Juliano
authors.initials: J
authors.lastname: Ferreira
authors.affiliation: Programa de Pós-graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense (Unesc), 88806-000 Criciúma, SC, Brazil. Electronic address: gabitrev@hotmail.com.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Trevisan
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D006321:Heart / Q000187:drug effects; D008297:Male; D008566:Membranes / Q000187:drug effects / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology*; D024301:Plant Bark / Q000737:chemistry; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D027823:Rhamnaceae / Q000737:chemistry*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D012997:Solvents; D014315:Triterpenes / Q000494:pharmacology*; D000097245:Ursolic Acid
chemical_list: D010936:Plant Extracts; D000254:Sodium-Potassium-Exchanging ATPase; D012997:Solvents; D014315:Triterpenes; D000097245:Ursolic Acid
keywords: Cardiotonic; Heart failure; High-performance liquid chromatography; Ouabain; Quercitrin; Ursolic acid