QUERCETIN PREVENTS DNA SINGLE-STRAND BREAKAGE AND CYTOTOXICITY CAUSEDBY TERT-BUTYLHYDROPEROXIDE - FREE-RADICAL SCAVENGING VERSUS IRON-CHELATING MECHANISM

Although the antioxidant properties of flavonoids are well documented, it is still unclear whether these effects are dependent on radical sc avenging or iron chelating activities. By using an experimental approa ch based on the notion that iron chelators suppress DNA strand scissio n and cytotoxicity caused by tert-butylhydroperoxide, whereas radical scavenging antioxidants prevent only the latter response, we provide e xperimental evidence indicating that the most prominent activity of th e flavonoid quercetin resides in its ability to chelate iron. This exp erimental approach can be utilized for the assessment of iron chelatio n in the biological activity of flavonoids or other antioxidants. (C) 1998 Elsevier Science Inc.