title: Development and validation method for simultaneous quantification of phenolic compounds in natural extracts and nanosystems.
abstract: BACKGROUND
  Sage and savoury (Salvia sp. and Satureja montana, respectively) are plants used in traditional medicine. The quality control of their herbal formulations is of paramount concern to guarantee the expected biological activity of their anti-oxidant compounds.
  
  
  OBJECTIVE
  To establish a simple and effective high-performance liquid chromatographic (HPLC) method to evaluate simultaneously quercetin and rosmarinic acid, in a pure form, in natural extracts (sage and savoury), and encapsulated into chitosan nanoparticles.
  
  
  METHODS
  Chromatography was performed on an RP C18 -column, in a gradient mode with a mobile phase comprising methanol:formic acid:water 92.5:2.5:5 (v/v) at a flow rate of 0.75 mL/min and at wavelength of 280 nm.
  
  
  RESULTS
  The method was specific, linear in the range of 0.05-1 mg/mL (R(2)  = 1.00), precise at the intraday and interday levels, accurate (recovery rate 90.5 ± 0.6%), and robust to changes in equipment conditions.
  
  
  CONCLUSIONS
  The method established was effective for quercetin and rosmarinic acid characterisation in natural extracts and in chitosan nanoparticles, allowing the loading capacity determination, the association efficiency as well as the in vitro release.
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo 228, 4050-313, Porto, Portugal; CBQF-Center of Biotechnology and Fine Chemistry, Biotechnology School of Portuguese Catholic University, Rua Dr. António Bernardino de Almeida, 4200-072, Porto, Portugal.
authors.forename: Sara Baptista
authors.initials: SB
authors.lastname: da Silva
authors.forename: Ana
authors.initials: A
authors.lastname: Oliveira
authors.forename: Domingos
authors.initials: D
authors.lastname: Ferreira
authors.forename: Bruno
authors.initials: B
authors.lastname: Sarmento
authors.forename: Manuela
authors.initials: M
authors.lastname: Pintado
mesh_terms: D048271:Chitosan / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002934:Cinnamates / Q000032:analysis*; D053630:Depsides / Q000032:analysis*; D057230:Limit of Detection; D053758:Nanoparticles / Q000032:analysis / Q000648:ultrastructure; D010936:Plant Extracts / Q000737:chemistry*; D010946:Plants, Medicinal / Q000737:chemistry*; D011794:Quercetin / Q000032:analysis*; D027543:Salvia officinalis / Q000737:chemistry*; D031362:Satureja / Q000737:chemistry*; D000097123:Rosmarinic Acid
chemical_list: D048271:Chitosan; D002934:Cinnamates; D053630:Depsides; D010936:Plant Extracts; D011794:Quercetin; D000097123:Rosmarinic Acid
keywords: HPLC; chitosan nanoparticles; quercetin; rosmarinic acid