ANTIOXIDANT ACTIONS OF THYMOL, CARVACROL, 6-GINGEROL, ZINGERONE AND HYDROXYTYROSOL

Antioxidants minimize oxidation of the lipid components in foods. Ther e is an increasing interest in the use of natural and/or synthetic ant ioxidants in food preservation, but it is important to evaluate such c ompounds fully for both antioxidant and pro-oxidant properties. The pr operties of thymol, carvacrol, 6-gingerol, hydroxytyrosol and zingeron e were characterized in detail. Thymol, carvacrol, 6-gingerol and hydr oxytyrosol decreased peroxidation of phospholipid liposomes in the pre sence of iron(III) and ascorbate, but zingerone had only a weak inhibi tory effect on the system. The compounds were good scavengers of perox yl radicals (CCl3O2; calculated rate constants > 10(6) M(-1) sec(-1)) generated by pulse radiolysis. Thymol, carvacrol, 6-gingerol and zinge rone were not able to accelerate DNA damage in the bleomycin-Fe(III) s ystem. Hydroxytyrosol promoted deoxyribose damage in the deoxyribose a ssay and also promoted DNA damage in the bleomycin-Fe(III) system. Thi s promotion was inhibited strongly in the deoxyribose assay by the add ition of bovine serum albumin to the reaction mixtures. Our data sugge st that thymol, carvacrol and 6-gingerol possess useful antioxidant pr operties and may become important in the search for 'natural' replacem ents for 'synthetic' antioxidant food additives.