Analysis of eleven phenolic compounds including novel p-coumaroyl derivatives in lettuce (Lactuca sativa L.) by ultra-high-performance liquid chromatography with photodiode array and mass spectrometry detection

Phytochem Anal. 2011 Nov-Dec;22(6):555-63. doi: 10.1002/pca.1318. Epub 2011 Mar 24.

Abstract

Introduction: Lettuce is a widely consumed vegetable and a good source of phenolic compounds. Several factors (genetic, agronomical and environmental) can influence the lettuce composition; their effects are not completely defined and more studies are needed on this topic.

Objective: To develop an improved ultra-high-performance liquid chromatography (UHPLC) method to quantify the main target intact phenolic compounds in lettuce.

Methodology: UHPLC identification of the compounds was supported by PAD spectra and MS(n) analyses. Quantification was carried out by PAD, by creating matrix-matched calibration curves at the specific wavelength for each compound.

Results: Sample pretreatment was simplified, with neither purification nor hydrolysis steps. Chromatographic conditions were chosen to minimise matrix interferences and to give a suitable separation of the major phenolic compounds within 27 min. The method allowed the quantification of 11 intact phenolic compounds in Romaine lettuces, including phenolic acids (caffeoyl and p-coumaroyl esters) and flavonoids (quercetin glycosides). Four p-coumaroyl esters were tentatively identified and quantified for the first time in lettuce.

Conclusion: The main intact phenolic compounds, including four novel p-coumaroyl esters, were simultaneously quantified in lettuce with optimal performances and a reduced total time of analysis. These findings make headway in the understanding of the lettuce phytochemicals with potential nutritional relevance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Caffeic Acids / analysis
  • Caffeic Acids / chemistry
  • Chlorogenic Acid / analysis
  • Chlorogenic Acid / chemistry
  • Chromatography, High Pressure Liquid / instrumentation
  • Chromatography, High Pressure Liquid / methods
  • Chromatography, High Pressure Liquid / standards
  • Coumaric Acids / analysis*
  • Coumaric Acids / chemistry
  • Esters / analysis
  • Esters / chemistry
  • Glucosides / analysis
  • Glucosides / chemistry
  • Lactuca / chemistry*
  • Mass Spectrometry
  • Molecular Structure
  • Phenols / analysis*
  • Phenols / chemistry
  • Plant Extracts / analysis
  • Plant Extracts / chemistry
  • Propionates
  • Quality Control
  • Quercetin / analogs & derivatives
  • Quercetin / analysis
  • Quercetin / chemistry
  • Quinic Acid / analysis
  • Quinic Acid / chemistry
  • Rutin
  • Succinates / analysis
  • Succinates / chemistry
  • Time Factors

Substances

  • Caffeic Acids
  • Coumaric Acids
  • Esters
  • Glucosides
  • Phenols
  • Plant Extracts
  • Propionates
  • Succinates
  • Quinic Acid
  • Chlorogenic Acid
  • Rutin
  • Quercetin
  • p-coumaric acid
  • chicoric acid