Structurally characterized zinc complexes of flavonoids chrysin and quercetin with antioxidant potential

Chrysin and quercetin are two of the most prominent and bioactive flavonoids with a wide spectrum of beneficial properties, including antioxidant and radical scavenging activity. The complexation of these flavonoids with transition metal ions of biological interest can lead to the generation of novel metallodrugs with improved pharmacological and biochemical properties. Within this framework, the synthesis and detailed structural and physico-chemical characterization of two novel heteroleptic complex assemblies of Zn(II) with chrysin and quercetin and the ancillary aromatic chelator 2,2′-bipyridine is presented. The two complexes represent the only crystallographically characterized structures with Zn(II) as the central metal ion and chrysin or quercetin as the ligands. The new complexes were biologically evaluated in vitro for their antioxidant potential, both exhibiting strong radical scavenging activity in the 2,2-diphenyl-1-picrylhydrazyl assay, and merit further investigation of their pharmacological profile.