Action of Curcumin as an Antioxidant against Lipid Peroxidation

Abstract

The antioxidant activity of curcumin, 1, 7-bis (4-hydroxy-3-methoxyphenyl) -1, 6-heptadiene-3, 5-dione, a natural antioxidant obtained from rhizome of Curcume longa L., and related compounds was measured against lipid peroxidation in various media. Curcumin reacted with stable radicals such as galvinoxyl and N, N-diphenyl-1-picrylhydrazyl, indicating it to possibly serve as a potent hydrogen donor, but no curcumin radical could be observed directly by electron spin resonance spectroscopy. Neither could the radical be spin trapped with a- (4-pyridyl-1-oxide) -N-t-butylnitrone. Curcumin suppressed the oxidation of methyl linoleate in organic homogeneous solution and aqueous emulsions, soybean phosphatidylcholine liposomal membranes, and rat liver homogenate induced by free radicals. Curcumin was a stronger antioxidant than 2, 6-di-t-butyl-4-methylphenol, Comparable to isoeugenol, but weaker than 3, 4-dihydroxycinnamic acid and 2-t-butyl-4-methoxyphenol.