Spectroscopy characterization, theoretical study and antioxidant activities of the flavonoids-Pb(II) complexes.

Lead is a prevalent toxic, nonessential heavy metal that has been considered as a major threat for human health. The intention of this work is to study the complexation of flavonoids (apigenin, chrysin, kaempferol and quercetin) with Pb(II) as well as antioxidant activities. The spectroscopy (AAS, UV–Vis, FT-IR, HPLC-MS, 1H NMR) and density functional theory (DFT) calculation were carried out to analyze complexation of flavonoids with Pb(II). In addition, antioxidant abilities of flavonoids were analyzed by FRAP and ABTS assays. The results of study indicate that complexation abilities of kaempferol and quercetin are stronger than apigenin and chrysin. Additionally, the main complexes are formed by reaction of flavonoids (except quercetin) with Pb(II) in a ratio of 2:1. It is indicated that kaempferol and quercetin have a promising prospect of becoming care ingredients for lead elimination. Image 1 • Quercetin has the strongest complexing ability in reaction with Pb(II). • The stoichiometries of the main complexes (except quercetin) are 2:1. • Kaempferol and quercetin still have strong antioxidant capacities after complexation. • Kaempferol and quercetin could be care ingredients for lead elimination. [ABSTRACT FROM AUTHOR]