Synthesis, Characterization and Antioxidant Property of QUERCETIN- Tb(III) Complex

Nearly all of flavonoids are good metal chelators and can chelate many metal ions to form different complexes. This article describes a synthesis of Quercetin–Tb(III) in methanol, characterized by using elemental analysis, UV–visible and evaluation of its antioxidant properties. The formation of complexes is realized from the UV–visible spectra which shows that the successive formation of Quercetin–Tb(III) occurs. To find out the antioxidant activity variation and the role of Tb(III) ion on the antioxidant activity of the complexes different radical scavenging methods such as: 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and 2,2′-azinobis 3-ethylbenzothiazoline-6-sulphonic acid (ABTS) were used. The results from DPPH, ABTS and FRAP methods showed that Quercetin and Quercetin–Tb(III) complex are capable of donating electron or hydrogen atom, and consequently could react with free radicals or terminate chain reactions in a time- and dose-dependent manner. This study showed that the chelation of metal ions by Quercetin decrease the redox potential of Quercetin-metal complex.