Lipids

, Volume 49, Issue 5, pp 481–494

Autoxidative and Photooxidative Reactivity of Highly Branched Isoprenoid (HBI) Alkenes

  • J.-F. Rontani
  • S. T. Belt
  • F. Vaultier
  • T. A. Brown
  • G. Massé
Original Article

DOI: 10.1007/s11745-014-3891-x

Cite this article as:
Rontani, JF., Belt, S.T., Vaultier, F. et al. Lipids (2014) 49: 481. doi:10.1007/s11745-014-3891-x

Abstract

Autoxidation of several mono-, di-, tri- and tetra-unsaturated highly branched isoprenoid (HBI) alkenes was induced in organic solvents using a radical initiator and enhancer, and their degradation rates were compared to those of classical phytoplanktonic lipids (mono-unsaturated fatty acids, sterols and chlorophyll phytyl side-chain). Autoxidation of two HBI trienes was also investigated in senescent and highly photodegraded diatom cells, collected in the Antarctic, using Fe2+ ions as radical inducers. Autoxidation rates of HBI alkenes were found to increase with the number of tri-substituted double bonds, as expected. Further, HBI trienes possessing one bis-allylic position (where hydrogen abstraction is highly favoured) were found to be particularly reactive towards autoxidation and degraded at similar rates compared to polyunsaturated fatty acids in diatom cells. By comparison of the autoxidation products of the most reactive tri-unsaturated HBI with the corresponding photooxidation products, some specific tracers of these two types of abiotic degradation processes were identified. The lack of reactivity of the mono-unsaturated HBI IP25 and a structurally similar di-unsaturated HBI towards autoxidative degradation supports the good preservation of these biomarkers in marine sediments.

Keywords

HBI alkenes Autoxidation Photooxidation Kinetic Senescent diatom cells Specific tracers 

Abbreviations

BSTFA

N,O-Bis(trimethysilyl)trifluoroacetamide

DCM

Dichloromethane

GC–EIMS

Gas chromatography–electron impact mass spectrometry

HBI

Highly branched isoprenoid

PUFA

Polyunsaturated fatty acid(s)

TLE

Total lipid extract

TMS

Trimethylsilyl

UVR

Ultra-violet radiation

Copyright information

© AOCS 2014

Authors and Affiliations

  • J.-F. Rontani
    • 1
    • 2
  • S. T. Belt
    • 3
  • F. Vaultier
    • 1
    • 2
  • T. A. Brown
    • 3
  • G. Massé
    • 4
  1. 1.Mediterranean Institute of Oceanography (MIO)Aix-Marseille UniversityMarseille Cedex 9France
  2. 2.Université du Sud Toulon-Var, CNRS-INSU/IRD UM 110La GardeFrance
  3. 3.Biogeochemistry Research Centre, School of Geography, Earth and Environmental SciencesUniversity of PlymouthPlymouthUK
  4. 4.Unité Mixte Internationale TakuvikPavillon Alexandre-Vachon, Université LavalQuebecCanada

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