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Evidence that Criegee intermediates drive autoxidation in unsaturated lipids
Meirong Zeng1, Nadja Heine1, Kevin R Wilson2
1Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720.
Summary
Autoxidation, a destructive process in organic molecules, may be driven by hydroxyl radical addition and Criegee intermediates, not just H-atom abstraction. This new mechanism explains rapid autoxidation, even with water present.
Area of Science:
- Chemistry
- Biochemistry
- Environmental Science
Background:
- Autoxidation is a free-radical chain reaction causing oxidative damage to organic molecules in various systems.
- Lipid autoxidation in cellular membranes is implicated in oxidative stress, aging, and cancer.
- The traditional mechanism involves H-atom abstraction and a peroxy-hydroperoxide cycle.
Purpose of the Study:
- To investigate an alternative mechanism for autoxidation in unsaturated lipids.
- To explore the role of hydroxyl radical addition and Criegee intermediates in autoxidation.
Main Methods:
- Studied a series of model unsaturated lipids.
- Presented evidence for a novel autoxidation pathway.
Main Results:
- Evidence supports a mechanism initiated by hydroxyl radical addition to double bonds.
- Chain reactions involving Criegee intermediates propagate this autoxidation.
- This pathway leads to rapid autoxidation, even in aqueous environments.
Conclusions:
- The established autoxidation mechanism may be incomplete.
- Criegee intermediates play a significant role in autoxidation.
- This finding has implications for understanding various chemical processes, including atmospheric chemistry.
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