Synthesis, molecular docking, and biological studies of novel heteroleptic Cu(II) and Zn(II) complexes of natural product-based semicarbazone derivatives

Abstract

In this study, we describe the synthesis of novel heteroleptic Cu(II) and Zn(II) complexes using two semicarbazone-based derivative ligands: ortho-phthalaldehyde disemicarbazone (L1) and dehydrozingerone semicarbazone (L2). The metal salts and the two ligands were used in a 1:1:1 ratio. The complexes were characterized by magnetic moment measurements, elemental analysis, SEM-EDX, liquid chromatography-mass spectrophotometer (LC-MS), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), UV-visible spectrophotometer, NMR, and FT-IR spectroscopy methods. Using the disk diffusion and DPPH procedures, the complexes' potential for scavenging free radicals and having antibacterial effects was examined. The results indicate that the ligand L1 has good mean inhibition zones on S. aureus (12.42 ± 0.23 mm) and S. pyogenes (11.64 ± 0.12 mm) bacteria. The [Cu(L1)(L2)] complex displayed higher antibacterial activities (13.67 ± 0.52 mm) against S. pyogenes bacteria, whereas [Zn(L1)(L2)] shows higher activity against P. Aeruginosa (14.22 ± 0.33 mm). Both complexes showed good antioxidant activity (63.7 % and 59.68 %). Furthermore, the docking results of the compounds against S. aureus Gyrase confirm the ligands (L1 and L2) and the complexes exhibit binding potentials of -7.39 to -11.01 kcal/mol. Higher value was obtained for the [Zn(L1)(L2)] complex (-11.01 kcal/mol). In order to enhance the biological activities of metal complexes, this study sheds light on the significance of multi-semicarbazone ligands and their corresponding complexes.