Synthesis, Characterization, Antioxidative Activity And DNA-binding Study On The Flavonoids Schiff-base Metal Complexes

In this paper, we have reported synthesis and characterization of flavonoids Schiff-base complexes, and studied their biological activities, such as antioxidative activity and DNA-binding. A great many hydrazones and their complexes with metals have provoked wide interest in their diverse spectra of biological and pharmaceutical activities, such as anticancer, antitumor and antioxidative activities, as well as the inhibition of lipid peroxidation etc. Our previous work showed that the rare earth complexes of the acylhydrazone derived from have certain scavenger effects on O₂^-In continuation of our work on the influence of the antioxidativea activity, we have synthesized A naringenin Schiff-base ligand (H3L) and its three complexes and characterized on the basis of elemental analyses, molar conductivity, IR spectra, ¹H NMR spectra and thermal analyses with a view to further investigating the antioxdative activities (scavenger effects on O₂^- and OH) and the properties of bindind to DNA.In the first chapter, the recent advances in the Schiff base complexes and flavonoids compounds have been reviewed. Their major research fields, such as antioxidant activity and biological activity have been summarized systematically.In the second chapter, a naringenin Schiff-base ligand (H3L) and its three complexes, MHL·nH₂O (M = Zn and Cu, n = 1) and NiH₂LOAc ·3.5H₂O, have been synthesized and characterized on the basis of elemental analysis, molar conductivity and i.r. spectrum, ¹H n.m.r., u.v. spectra and thermal analyses. In addition, the suppression ratio for O₂^- · (a) and the suppression ratio for OH· (b) were determined by the use of 721 spectrophotometer. The results show that compared to the ligand, the complexes exhibit high activity in the suppression of O₂^- · (a) and OH· (b).In the third chapter, we investigate the interactions of flavonoids Schiff-base ligand (H₃L) and its copper(II) and zinc(II) complexes and PMBPH, LaPMBPH with calfthymus DNA. The DNA binding properties of the compounds have been investigated by fluorescence spectroscopy, ultraviolet spectroscopy and by viscosity measurements. The results indicate that complexes and ligand may bind to DNA by intercalation modes, but the binding affinity of the complexes is much higher than that of the ligand.In the fourth chapter, the chromones Schiff-base ligand (L2) and its rare earth complex have been synthesized. Due to the limit of time, the structure of the chromones schiff-base ligand (L2) and its rare earth complex have not been characterized enough.