title: Advances in isoflavone profile characterisation using matrix solid-phase dispersion coupled to HPLC/DAD in Medicago species.
abstract: BACKGROUND
  Analytical methods used in phytochemistry analysis are limited by the sample preparation step, which should ideally be fast, accurate, ecofriendly and achievable using low quantities of the sample. Matrix solid-phase dispersion (MSPD) may be a good alternative for combining extraction and purification procedures, thereby reducing the indicated limitations.
  
  
  OBJECTIVE
  Applying an MSPD extraction procedure coupled to high-performance liquid chromatography diode-array detection (HPLC/DAD) as an alternative methodology to evaluate isoflavone profiles.
  
  
  METHODS
  Isoflavone profiles were determined for the leaves of nine species of Medicago in the late flower phenological stage (one or more nodes with 50% open flowers, no seed pods). Extraction was performed following MSPD, and isoflavone profiles were characterised using HPLC/DAD. The quantified amounts were compared with previous results in different species commonly recognised as good sources of isoflavones.
  
  
  RESULTS
  Formononetin was the major isoflavone in most species, except M. polymorpha and M. truncatula. The isoflavone amounts were significantly different among the assayed species, with M. orbicularis and M. arabica as the major isoflavone sources, while M. rigidula presented the lowest contents. Furthermore, the detected differences allow electing the best species as a primary source of a specific isoflavone.
  
  
  CONCLUSIONS
  The MSPD allowed good extraction efficiency, reproducibility and recovery. Some of the species showed relevant isoflavone contents, even when compared with acknowledged plant sources such as soy or red clover. To the best of our knowledge the results presented are reported for the first time in these species.
authors.affiliation: CIBIO-ICETA, Faculdade de Ciências, Universidade do Porto, R. Padre Armando Quintas, 4485-661, Vairão, Portugal; REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, nº 228, 4050-313.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Visnevschi-Necrasov
authors.forename: João C M
authors.initials: JC
authors.lastname: Barreira
authors.forename: Sara C
authors.initials: SC
authors.lastname: Cunha
authors.forename: Graça
authors.initials: G
authors.lastname: Pereira
authors.forename: Eugénia
authors.initials: E
authors.lastname: Nunes
authors.forename: M Beatriz P P
authors.initials: MB
authors.lastname: Oliveira
mesh_terms: D002851:Chromatography, High Pressure Liquid; D035264:Flowers / Q000737:chemistry; D007529:Isoflavones / Q000032:analysis* / Q000737:chemistry; D029902:Medicago / Q000737:chemistry*; D015394:Molecular Structure; D018515:Plant Leaves / Q000737:chemistry; D015203:Reproducibility of Results; D052616:Solid Phase Extraction / Q000379:methods*; D013997:Time Factors
chemical_list: D007529:Isoflavones; C007768:formononetin
keywords: HPLC/DAD; MSPD; Medicago; interspecific variation; isoflavones