Quercetin-phenylalanine 3d-transition metal-based {Co(II), Ni(II) & Cu(II)} intercalative therapeutic agents: DNA & BSA interaction studies in vitro and cleavage activity

Abstract

New Quercetin-phenylalanine metal-based therapeutic agents of the formulation [Qu(Phe)M(II).(H2O)2].NO3 where M(II) = Co(II) and Ni(II) and [Qu(Phe)Cu(II).(H2O)2] were synthesized and their structure was predicted by IR, UV–vis, EPR and ESI-MS spectroscopic techniques. The bio-molecular interaction studies of the Quercetin-phenylalanine complexes, 1–3 with ct-DNA and BSA were performed using a battery of complimentary biophysical techniques. The corroborative results of these experiments revealed strong binding propensity via electrostatic interactions probably through minor grove binding towards ct-DNA, therapeutic target. The binding affinity of Quercetin-phenylalanine complexes 1–3 was quantified by determining binding constants values, Kb, Ksv, and the magnitude of binding propensity followed the order 3 > 1 > 2, implicating the preferential binding of Cu(II) complex 3 with ct-DNA. The cleavage studies were performed with complexes using gel electrophoretic mobility assay. The complexes 1–3 demonstrated efficient cleaving ability by the hydrolytic cleavage pathway involving hydroxyl (OH) radicals. BSA binding profile of Quercetin-phenylalanine metal therapeutics 1–3 was studied in order to understand the drug carrier potential of these compounds and found that complex 3 was capable of binding preferentially with BSA as compared to other complexes.