title: Metabolite profiling of leek (Allium porrum L) cultivars by (1) H NMR and HPLC-MS.
abstract: BACKGROUND
  Leek (Allium ampeloprasum var. porrum) is consumed as a vegetable throughout the world. However, little is known about the metabolites of leek cultivars, especially those with potentially important beneficial properties for human health.
  
  
  OBJECTIVE
  We provide new information for the overall metabolite composition of several leek cultivars grown in Europe by using HPLC-MS and (1) H NMR.
  
  
  METHODS
  The use of a novel CTLS/NMR (constrained total-line-shape nuclear magnetic resonance) approach was found to be capable of reliable quantification, even with overlapping metabolite signals in the (1) H NMR of plant metabolites. Additionally, a new application for leek flavonoids was optimised for HPLC-MS.
  
  
  RESULTS
  The total concentration of carbohydrates (glucose, fructose, kestose/nystose and sucrose) and nine amino acids varied by fourfold in leek juice from different cultivars, while the total concentrations of four organic acids were similar in all cultivars. All the quantified flavonols were kaempferol derivatives or quercetin derivatives and threefold differences in flavonol concentrations were detected between cultivars.
  
  
  CONCLUSIONS
  In this study, various phytochemical profiles were determined for several leek cultivars by (1) H NMR spectroscopy with CTLS combined with HPLC-MS. The wide variation in bioactive compounds among commercial leek cultivars offers promising opportunities for breeders to raise the levels of important biochemical compounds in leek breeding lines, and also provides some objective measure for quality assurance for the leek industry.
authors.affiliation: School of Pharmacy, Biocenter Kuopio, University of Eastern Finland, P.O. Box 1627, FI, 70211, Kuopio, Finland.
authors.forename: Tuula H
authors.initials: TH
authors.lastname: Soininen
authors.forename: Niko
authors.initials: N
authors.lastname: Jukarainen
authors.forename: Pasi
authors.initials: P
authors.lastname: Soininen
authors.forename: Seppo O K
authors.initials: SO
authors.lastname: Auriola
authors.forename: Riitta
authors.initials: R
authors.lastname: Julkunen-Tiitto
authors.forename: Wieslaw
authors.initials: W
authors.lastname: Oleszek
authors.forename: Anna
authors.initials: A
authors.lastname: Stochmal
authors.forename: Reijo O
authors.initials: RO
authors.lastname: Karjalainen
authors.forename: Jouko J
authors.initials: JJ
authors.lastname: Vepsäläinen
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002241:Carbohydrates / Q000032:analysis; D002264:Carboxylic Acids / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003903:Deuterium / Q000032:analysis; D005060:Europe; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods; D019697:Onions / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D000596:Amino Acids; D002241:Carbohydrates; D002264:Carboxylic Acids; D005419:Flavonoids; D010936:Plant Extracts; D003903:Deuterium
keywords: 1H NMR; Allium porrum; HPLC-MS; amino acids; carbohydrates; flavonols; food components; leek