Complexos de vanilina e derivados: síntese, caracterização e estudo biológico

Abstract

The main objective of the present work is to contribute to the development of bioinorganic chemistry of the vanilloid systems with copper(II) and zinc(II) metal ions through the synthesis and structural study of new metal complexes of copper(II)-phen and zinc(II)-phen associated with vanilloid ligands of biological interest. Among the compounds synthesized, the [Cu(phen)(van)2] and [Zn(phen)(van)2] complexes is highlighted, with structures elucidated by X-ray diffraction, associated with spectroscopic and electrochemical techniques, which evidenced the formation of an octahedral system with tetragonal distortion with axial axis elongation (copper complex) and compression of the axial axis (zinc complex). Biological assays performed with [Cu(phen)(van)2] demonstrated high antitumor activity. These results motivated the development of the new derivatives [M(phen)(vglu)2], CS-MPV, [M(phen)(vpca)2] and [M(phen)(vpcaZnCl2)2], with M = Cu2+ e Zn2+, which may potentiate the anticancer activity already presented by this system. These derivatives were characterized by IV and UV-Vis, with the copper complexes still characterized by electrochemistry and the zinc complexes characterized by 1H NMR. Through the infrared and UV-Vis it was possible to indicate the presence of the ligand phenanthroline in all the synthesized complexes, through stretches of phen rings and intense bands with π-π transitions in the ultraviolet region, respectively. The formed Schiff bases were indicated by stretching the C=N (IV) group and nπ * transitions of the imine group (UV-Vis). The ciclic voltammograms of copper complexes have metal redox pair, related to the Cu2+/Cu1+ redox process, as well as oxidation processes of vanilloid ligands. The 1H NMR spectra showed signals at shifts and couplings that are consistent with the structures proposed for zinc (II) complexes. In CS-MPV, chitosan films were modified with [M(phen)(van)2], where in aqueous media the precursor complexes are easily released and can act as loading systems that can be selective for the route and form of administration of complexes with vanillin. In addition to the structural characterization, the CS-MPV was analyzed for the release and quantification of [M(phen)(van)2] present in the films, through UV-Vis and electrochemistry. The in vivo assays performed with the CS-ZPV films showed potential healing activity in skin wounds to the [Zn(phen)(van)2] complex released in rat injury