Protection by albumin against the pro-oxidant actions of phenolic dietary components.

Synthetic and natural phenolic compounds are increasingly used in food preservation. Carnosol and carnosic acid (active components of rosemary extract), flavonoids (morin, quercetin, fisetin, myricetin), other plant phenolics (gossypol) and propyl gallate may protect lipids against oxidative damage but have the potential to increase damage to non-lipid constituents of foods, such as carbohydrates and DNA. Thus, in the presence of ferric EDTA and H2O2, they can form highly reactive hydroxyl radicals that can degrade the sugar deoxyribose and/or accelerate DNA degradation by means of a ferric-bleomycin complex. Human and bovine serum albumin afford considerable protection against damage to deoxyribose and DNA mediated by the above reactions. It is suggested that, given the fortification of foods with iron and EDTA and the use of phenolic substances as 'antioxidant' food additives, the addition of albumin might afford some protection.