AAPH is a water-soluble azo compound which is used extensively as a free radical generator, often in the study of lipid peroxidation and the characterization of antioxidants.1,2,3,4 Decomposition of AAPH produces molecular nitrogen and 2 carbon radicals. The carbon radicals may combine to produce stable products or react with molecular oxygen to give peroxyl radicals. The half-life of AAPH is about 175 hours (37°C at neutral pH), making the rate of free radical generation essentially constant during the first several hours in solution.5 While AAPH may be used effectively for lipid peroxidation in aqueous dispersions of fatty acids, other radical generators may be better suited for peroxidation studies in lipid micelles or membranes.6,7
1
Noguchi, N., Takahashi, M., Tsuchiya, J., et al. Action of 21-aminosteroid U74006F as an antioxidant against lipid peroxidation. Biochem Pharmacol55785-791(1998).
2
Liu, Z., Yu, W., and Liu, Z. Antioxidative and prooxidative effects of coumarin derivatives on free radical initiated and photosensitized peroxidation of human low-density lipoprotein. Chem Phys Lipids103125-135(1999).
3
Rice-Evans, C., and Miller, N. Total antioxidant status in plasma and body fluids. Methods Enzymol234(24)279-293(1994).
4
Liégeois, C., Lermusieau, G., and Collin, S. Measuring antioxidant efficiency of wort, malt, and hops against the 2,2'-azobis(2-amidinopropane) dihydrochloride-induced oxidation of an aqueous dispersion of linoleic acid. J Agric Food Chem481129-1134(2000).
5
Niki, E. Free radical initiators as source of water- or lipid-soluble peroxyl radicals. Methods Enzymol186100-108(1990).
6
Yamamoto, Y., Haga, S., Niki, E., et al. Oxidation of lipids. V. Oxidation of methyl linoleate in aqueous dispersion. Bull Chem Soc Jpn57(5)1260-1264(1984).
7
Culbertson, S.M., and Porter, N.A. Unsymmetrical azo initiators increase efficiency of radical generation in aqueous dispersions, liposomal membranes, and lipoproteins. J Am Chem Soc1224032-4038(2000).
Noguchi, N., Takahashi, M., Tsuchiya, J., et al. Action of 21-aminosteroid U74006F as an antioxidant against lipid peroxidation. Biochem Pharmacol55785-791(1998).
Liu, Z., Yu, W., and Liu, Z. Antioxidative and prooxidative effects of coumarin derivatives on free radical initiated and photosensitized peroxidation of human low-density lipoprotein. Chem Phys Lipids103125-135(1999).
Rice-Evans, C., and Miller, N. Total antioxidant status in plasma and body fluids. Methods Enzymol234(24)279-293(1994).
Niki, E. Free radical initiators as source of water- or lipid-soluble peroxyl radicals. Methods Enzymol186100-108(1990).
Yamamoto, Y., Haga, S., Niki, E., et al. Oxidation of lipids. V. Oxidation of methyl linoleate in aqueous dispersion. Bull Chem Soc Jpn57(5)1260-1264(1984).
Liégeois, C., Lermusieau, G., and Collin, S. Measuring antioxidant efficiency of wort, malt, and hops against the 2,2'-azobis(2-amidinopropane) dihydrochloride-induced oxidation of an aqueous dispersion of linoleic acid. J Agric Food Chem481129-1134(2000).
Culbertson, S.M., and Porter, N.A. Unsymmetrical azo initiators increase efficiency of radical generation in aqueous dispersions, liposomal membranes, and lipoproteins. J Am Chem Soc1224032-4038(2000).