Chelation of Iron and Copper by Quercetin B-Ring Methyl Metabolites, Isorhamnetin and Tamarixetin, and Their Effect on Metal-Based Fenton Chemistry
2021
Abstract
Quercetin is extensively metabolized in humans, e.g. into isorhamnetin and tamarixetin. Both metabolites chelated both iron and copper; however, there were some significant differences between them notwithstanding that the major chelation site (3-hydroxy-4-keto) was the same.
Mostly, complexes 2:1, flavonoid to metal, were observed. Both compounds reduced iron and copper in a bell-shaped manner with tamarixetin being less potent in general.
Both metabolites potentiated the Fenton reaction triggered by iron, while they were able to decrease the copper-based Fenton reaction under acidic conditions. In cellular experiments, both metabolites attenuated the copper triggered hemolysis.