Stable nitroxides as lipid antioxidants.

Abstract

STABLE nitroxides have been shown by Neiman et al.1,2 and Brownlie and Ingold3 to be inhibitors of polymerization. Hoffman4 mentioned that di-t-butyl nitroxide was an effective antioxidant, polymerization inhibitor and radical trap, but no details were given. According to Neiman et al.1 and Brownlie and Ingold3 the nitroxide radical reacts with an alkyl radical, stopping the chain reaction as follows The nitroxides compete favourably with oxygen for the R radical1, and propagation is said to be prevented with little or no peroxide formation. Work in this laboratory5 suggested that nitroxide radicals were involved in the antioxidant activity of secondary aliphatic hydroxyl-amines toward unsaturated lipids. Some of the known stable nitroxide radicals have now been examined.