Lipids

, Volume 43, Issue 6, pp 533–548

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

Authors

    • US Department of AgricultureAgricultural Research Service, Eastern Regional Research Center
    • Crop Conversion Science and Engineering Research Unit, ERRC, ARS, USDA
  • Douglas C. Doehlert
    • US Department of AgricultureAgricultural Research Service, Cereal Crops Research Unit
  • Ruth Welti
    • Kansas Lipidomics Research Center, Division of BiologyKansas State University
  • Giorgis Isaac
    • Kansas Lipidomics Research Center, Division of BiologyKansas State University
  • Mary Roth
    • Kansas Lipidomics Research Center, Division of BiologyKansas State University
  • Pamela Tamura
    • Kansas Lipidomics Research Center, Division of BiologyKansas State University
  • Alberto Nuñez
    • US Department of AgricultureAgricultural Research Service, Eastern Regional Research Center
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