Caffeic acid phenethyl ester (CAPE): correlation of structure and antioxidant properties.

Caffeic acid phenethyl ester (CAPE), a plant polyphenolic concentrated in honeybee propolis, has been found to be biologically active in a variety of pathways. The aim of this study was to determine the antioxidant activity of CAPE using different methods such as total antioxidant activity by the thiocyanate method, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid radicals, 1,1-diphenyl-2-picryl-hydrazyl free radicals, N,N-dimethyl-p-phenylenediamine dihydrochloride radicals and superoxide anion radicals scavenging activities, reducing power and ferrous ions (Fe(2+)) chelating activities. CAPE showed 97.9% inhibition on lipid peroxidation of linoleic acid emulsion. On the other hand, butylated hydroxyanisole, butylated hydroxytoluene, α-tocopherol and trolox indicated an inhibition of 87.3, 97.6, 75.3 and 90.3% on peroxidation in the same system, respectively.