Antibacterial, antifungal, DNA interactions, and antioxidant evaluation of Cu(II) Co(II), Ni(II), Mn(II) and UO2(II) mixed ligand metal complexes: Synthesis, characterization and molecular docking studies

Abstract

The current work was designed to prepare novel 1:1:1 Metal (M): primary ligand (HL1): co-ligand (HL2) complexes; [Cu(L1)(L2)(OH2)2] (1), [Co(L1)(L2)]H2O (2), [Ni(L1)(L2)(OH2)2] 0·.75H2O (3) and [Mn(L1)(L2)(OH2)2] 4·.5H2O (4) and [UO2(L1)(L2)] (5) from ligands 7-Formyl-8-hydroxyquinoline (oxine) (HL1), 2-aminophenol (HL2) and characterized by analytical and spectroscopic techniques. FTIR, mass spectra, ESR techniques, elemental analysis, and thermal analysis were used to characterize the newly formed complexes. The results of the elemental analysis show the formation of [HL1:M:HL2] complexes. The ligands act as a mononegative bidentate chelating agent coordinating through C = O, NH2 and two OH groups by replacement of a proton from the latter groups. The molecular docking between the protein receptors and the ligand (HL1), ligand (HL2) and its mixed ligand metal complexes (1–5) was studied. The interface between HL2, complexes and calf thymus DNA (CT-DNA) displays hypochromism behavior. The binding value constant (Kb) are calculated and found to be 5.29 × 103, 8.49 × 104, 2.45 × 105, 2.96 × 104 and 1.16 × 104, 3.08 × 104 M−1 for HL2 and its mixed ligand metal complexes (1–5), respectively. Antimicrobial properties of ligands and the synthesized complexes were also screened versus G + ve bacteria (S. aureus and B. cereus), G-ve bacteria (K. pneumoniae, Pseudomonas sp. and E. coli, and fungi (F. oxysporum, A. niger, and C. albicans). The obtained results revealed the strong antimicrobial action of metal complexes with MIC, MBC and MFC values ranging from 5 to 45 µg/ml. HL1 showed higher antimicrobial and antioxidant activities than HL2 and major of the prepared metal complexes. All metal mixed ligand complexes inhibited the multidrug-resistant bacterium; Klebsiella pneumoniae compared to the standard antibiotic, penicillin G. Also, all metal mixed ligand complexes showed potent antifungal activities against both Aspergillus niger and Candida albicans.