Lipids

, Volume 43, Issue 6, pp 533–548

The Identification of Mono-, Di-, Tri-, and Tetragalactosyl-diacylglycerols and their Natural Estolides in Oat Kernels

  • Robert A. Moreau
  • Douglas C. Doehlert
  • Ruth Welti
  • Giorgis Isaac
  • Mary Roth
  • Pamela Tamura
  • Alberto Nuñez
Original Article

DOI: 10.1007/s11745-008-3181-6

Cite this article as:
Moreau, R.A., Doehlert, D.C., Welti, R. et al. Lipids (2008) 43: 533. doi:10.1007/s11745-008-3181-6

Abstract

Oat kernels were extracted with methanol, and glycolipid-enriched fractions were prepared using silica solid phase extraction. Using direct infusion electrospray ionization (ESI) tandem mass spectrometry (MS), high performance liquid chromatography (HPLC)-ESI-MS, and HPLC-atmospheric pressure chemical ionization (APCI)-MS, we confirmed previous reports that digalactosyldiacylglycerol (DGDG) was the most abundant glycolipid in oat kernels and confirmed a previous report of the presence of a DGDG mono-estolide in oat kernels. In the current study we also identified several additional natural galactolipid estolides: two new DGDG estolides (di- and tri-estolides), two trigalactosyldiacylglycerol (TriGDG) estolides (mono- and di-estolides), and one tetragalactosyldiacylglycerol (TetraGDG) estolide (mono-estolide). The levels of total galactolipid estolides in oat kernels were estimated to be about 29% of the total glycolipid fraction. To our knowledge, this report is the first evidence of natural di- and tri-estolides of polar lipids.

Keywords

Oat kernelsEstolidesDigalactosyldiacylglycerolTrigalactosyldiacylglycerolTetragalactosyldiacylglycerolGalactolipidMass spectrometry

Abbreviations

APCI

Atmospheric pressure chemical ionization

CID

Collision-induced dissociation

DAG

Diacylglycerol

DGDG

Digalactosyldiacylglycerol

DGMG

Digalactosylmonoacylglycerol

ESI

Electrospray ionization

ELSD

Evaporative light scattering detector

EIC

Extracted ion chromatogram

HPLC

High-performance liquid chromatography

MS

Mass spectrometry

MGDG

Monogalactosyldiacylglycerol

NL

Neutral loss

NP

Normal-phase

RP

Reverse-phase

SPE

Solid phase extraction

MS/MS

Tandem mass spectrometry

TetraGDG

Tetragalactosyldiacylglycerol

TIC

Total ion chromatogram

TriGDG

Trigalactosyldiacylglycerol

TriGMG

Trigalactosylmonoacylglycerol

Copyright information

© US Government 2008

Authors and Affiliations

  • Robert A. Moreau
    • 1
    • 4
  • Douglas C. Doehlert
    • 2
  • Ruth Welti
    • 3
  • Giorgis Isaac
    • 3
  • Mary Roth
    • 3
  • Pamela Tamura
    • 3
  • Alberto Nuñez
    • 1
  1. 1.US Department of AgricultureAgricultural Research Service, Eastern Regional Research CenterWyndmoorUSA
  2. 2.US Department of AgricultureAgricultural Research Service, Cereal Crops Research UnitFargoUSA
  3. 3.Kansas Lipidomics Research Center, Division of BiologyKansas State UniversityManhattanUSA
  4. 4.Crop Conversion Science and Engineering Research Unit, ERRC, ARS, USDAWyndmoorUSA