Identification of New Pharmacophore in Bioactive Palladium Schiff Base Metal Complexes of Cephalosporins: Synthesis, Characterization and Biological Activity

摘要

ABSTRACT Growing numbers of antibiotic-resistant bacteria are putting this golden era of medicine at risk and stresses the need for regular monitoring of antibiotic susceptibility, and developing a new design being active against resist pathogens. In this view seven Schiff base ligands of Cephalosporin group antibiotics were synthesized by their condensation with salicylaldehyde in equimolar ratio. Complexes of these Schiff bases with Pd (II) metal were synthesized in 1:2 stoichiometric ratio. The complexes were formulated as [Pd(L)2].3H2O, where L is Schiff base of seven different cephalosporin antibiotics. Complexes were characterized by elemental analyses, molar conductance, UV-Visible, FT-IR, 1H-NMR, 13C{1H}-NMR, 2D-NMR and ESI-Mass spectrometry. Schiff bases were coordinated with metal through phenolic oxygen and azomethine-N, giving simple square planar geometry to complexes. Complexes were tested for antibacterial activity and MIC against gram-negative bacteria E. coli and gram positive bacteria S. aureus and were found more potent than Schiff bases and precursor antibiotics. Keywords: Cephalosporin groups, Palladium Complexes, Schiff base, Antibacterial activity, Pharmacophore.