title: Direct proof by (13)C-nuclear magnetic resonance of semi-purified extract and isolation of ent-Catechin from leaves of Eucalyptus cinerea.
abstract: BACKGROUND
  Eucalyptus cinerea F. Muell. ex Benth. is native to Australia and acclimatized to Southern Brazil. Its aromatic leaves are used for ornamental purposes and have great potential for essential oil production, although reports of its use in folk medicine are few.
  
  
  OBJECTIVE
  This study evaluated the composition of E. cinerea leaves using the solid state (13)C-nuclear magnetic resonance (NMR) and isolation of the compound from the semipurified extract (SE).
  
  
  METHODS
  The SE of E. cinerea leaves was evaluated in the solid state by (13)C-NMR spectrum, and the SE was chromatographed on a Sephadex LH-20 column, followed by high-speed counter-current chromatography to isolate the compound. The SE was analyzed by (13)C-NMR and matrix-assisted laser desorption/ionization-time-of-flight spectra.
  
  
  RESULTS
  Flavan-3-ol units were present, suggesting the presence of proanthocyanidins as well as a gallic acid unit. The uncommon ent-catechin was isolated.
  
  
  CONCLUSIONS
  The presence of ent-catechin is reported for the first time in this genus and species.
authors.affiliation: Postgraduate Program in Pharmaceutical Sciences, Universidade Federal do Paraná, Av. Lothário Meissner, 632, BR-80210-170, Curitiba, PR, Brazil.
authors.forename: Sayonara Mendes
authors.initials: SM
authors.lastname: Silva
authors.affiliation: Pharmacy Student, Universidade Federal do Paraná, Av. Lothário Meissner, 632, BR-80210-170, Curitiba, PR, Brazil.
authors.forename: Simone Yae
authors.initials: SY
authors.lastname: Abe
authors.affiliation: Postgraduate Program in Pharmaceutical Sciences, Palafito, Universidade Estadual de Maringá, Av. Colombo, 5790, BR-87020-900, Maringá, Brazil.
authors.forename: Fernanda Giacomini
authors.initials: FG
authors.lastname: Bueno
authors.affiliation: Department of Chemistry, Faculty of Pharmaceutical Sciences, Universidade de São Paulo, Ribeirão Preto, BR-14040-900, Ribeirão Preto, SP, Brazil.
authors.forename: Norberto Peporine
authors.initials: NP
authors.lastname: Lopes
authors.affiliation: Postgraduate Program in Pharmaceutical Sciences, Palafito, Universidade Estadual de Maringá, Av. Colombo, 5790, BR-87020-900, Maringá, Brazil.
authors.forename: João Carlos Palazzo
authors.initials: JC
authors.lastname: de Mello
authors.affiliation: Postgraduate Program in Pharmaceutical Sciences, Universidade Federal do Paraná, Av. Lothário Meissner, 632, BR-80210-170, Curitiba, PR, Brazil.
authors.forename: Tomoe
authors.initials: T
authors.lastname: Nakashima
keywords: Circular dichroism; Eucalyptus cinerea; ent-catechin; flavan-3-ol units; solid-state 13C-nuclear magnetic resonance