title: Reversed-phase-liquid chromatography method for separation and quantification of gallic acid from hydroalcoholic extracts of Qualea grandiflora and Qualea parviflora.
abstract: BACKGROUND
  Qualea parviflora and Qualea grandiflora (Vochysiaceae), commonly known in Brazil as "pau-terra" and "pau-terrinha," respectively, have been widely used in the treatment of ulcer and gastritis. These therapeutic effects are attributed to various compounds present in the plants, including phenolic compounds such as gallic acid, due to their important antioxidant activity.
  
  
  OBJECTIVE
  The aim of the present study was to validate a high performance liquid chromatography with diode array detection (HPLC-DAD) method for the quantitative determination of gallic acid in the stem bark of Q. parviflora and Q. grandiflora hydroalcoholic extracts.
  
  
  METHODS
  The chromatography analysis was successfully achieved on a Dionex column, Acclaim(®) 120 (250 mm × 4.60 mm, 5 µm) with a gradient elution of water and methanol at a flow rate of 0.8 mL/min and ultraviolet detection at 280 nm.
  
  
  RESULTS
  The validation data, including linearity, precision, specificity, accuracy and robustness of this method demonstrated good reliability and sensitivity.
  
  
  CONCLUSIONS
  The method is able to quantify gallic acid in the stem bark of both species. What is more, the chromatographic peaks showed good resolution and there are also the advantages of easy sample preparation and a short time between each injection.
authors.affiliation: Laboratory of Pharmacognosy, University of Brasília - UnB, Brasília-DF, Brazil ; Post Graduate Programme in Therapeutic Innovation, Federal University of Pernambuco - UFPE, Recife-PE, Brazil ; Pharmacognosy Laboratory, Federal University of Pernambuco - UFPE, Recife-PE, Brazil.
authors.forename: Mariana L
authors.initials: ML
authors.lastname: de Mesquita
authors.affiliation: Post Graduate Programme in Therapeutic Innovation, Federal University of Pernambuco - UFPE, Recife-PE, Brazil ; Pharmacognosy Laboratory, Federal University of Pernambuco - UFPE, Recife-PE, Brazil.
authors.forename: Waleska F
authors.initials: WF
authors.lastname: Leão
authors.affiliation: Post Graduate Programme in Therapeutic Innovation, Federal University of Pernambuco - UFPE, Recife-PE, Brazil.
authors.forename: Magda R A
authors.initials: MR
authors.lastname: Ferreira
authors.affiliation: Plant Anatomy Laboratory, University of Brasília - UnB; Brasília-DF, Brazil.
authors.forename: José E
authors.initials: JE
authors.lastname: de Paula
authors.affiliation: Laboratory of Pharmacognosy, University of Brasília - UnB, Brasília-DF, Brazil.
authors.forename: Laila S
authors.initials: LS
authors.lastname: Espindola
authors.affiliation: Post Graduate Programme in Therapeutic Innovation, Federal University of Pernambuco - UFPE, Recife-PE, Brazil ; Pharmacognosy Laboratory, Federal University of Pernambuco - UFPE, Recife-PE, Brazil.
authors.forename: Luiz A L
authors.initials: LA
authors.lastname: Soares
keywords: Gallic acid; Qualea grandiflora; Qualea parviflora; high-performance liquid chromatography with diode array detection; validation