Synthesis and characterization of mixed ligand complexes of lomefloxacin drug and glycine with transition metals. Antibacterial, antifungal and cytotoxicity studies

Mixed ligand complexes derived from lomefloxacin (LFX, L1) as primary ligand and glycine (L2) as secondary ligand have been prepared and characterized by conventional techniques including elemental analyses, XRD, infrared, electronic spectra, molar conductivity and thermal analyses. The elemental analyses data display the formation of 1:1:1 [M:L1:L2] complexes. The diffused reflectance and magnetic moment measurements reveal the presence of the complexes in an octahedral geometry. The infrared spectral data show that the chelation behavior of the ligands toward transition metal ions is through carbonyl O, and carboxylate O of LFX whereas the amino acid coordinate through the carboxylate oxygen and the amino nitrogen. The electronic spectral results display the existence of π–π∗ (phenyl rings), n–π∗ (NH2 and CN) and confirm the mentioned structure. The molar conductivity reveals an electrolytic nature of all chelates. The thermogravimetric analysis data of the complexes displays the existence of hydrated and coordinated water molecules. The effect of LFX, glycine and their complexes on the inhibition of bacteria or fungi growth were evaluated. The prepared complexes were found to exhibit enhanced activity on bacteria or fungi growth compared to LFX and glycine ligands. LFX, [Mn(LFX)(Gly)(H2O)2]·Cl, [Co(LFX)(Gly)(H2O)2]·Cl and [Zn(LFX)(Gly)(H2O)2]·Cl were found to be very active against breast cancer cells with IC50 values 14, 11.2, 13 and 16.8, respectively, while glycine and other complexes had been shown to be inactive at lower concentration than 100 μg/ml.