Quercetin and its ester derivatives inhibit oxidation of food, LDL and DNA.

Quercetin was esterified with fatty acids (FA) in order to expand its application in a wide range of food and biological systems. The antioxidant potential of the esters were examined using hydroxyl radical scavenging activity, antioxidation in oil-in-water emulsion and bulk oil, inhibition of low-density lipoprotein (LDL) oxidation and deoxyribonucleic acid (DNA) scission. Except for oil-in-water emulsion system, quercetin derivatives demonstrated similar and/or better antioxidant activity than quercetin itself in bulk oil (quercetin with C18:1 and C22:6), hydroxyl radical scavenging assay (quercetin with C3:0-C8:0), DNA scission (quercetin with C3:0-C8:0), and LDL oxidation (quercetin with C14:0-C22:6, except C18:0). These results suggest that esterification did not compromise the antioxidant activity of the parent compound and quercetin derivatives might be useful as possible antioxidants in food and biological systems.