Synthesis Characterization and In Vitro Pharmacological Evaluation of Oxalyldihydrazone and its Metal(II) Complexes

Abstract

Drug resistance is a renowned condition that results when diseases become tolerant to chemotherapeutic agents. Even though, several classes of antibacterial and antifungal compounds are presently accessible, the resistance of microorganisms to these drugs has been continuously emerging.  In order to address this problematic condition, it is crucial to discover new drugs with novel mechanisms of action, higher activity and improved selectivity. Complexes are gaining more attention in the design of drugs. This had led to lots of studies on metal-based drugs. Ni(II), Cu(II) and Zn(II) complexes of dihydrazone derived from oxalyldihydrazide and terephthalaldehyde were synthesized by salvo-thermal method and characterized by spectral and physicochemical techniques. The free ligand has a melting point of 176 °C and the complexes decomposed between 211 - 289 °C, which indicate their good thermal stability. The molar conductance values of the complexes were in the range of 9.8 - 20.3 W^–1cm^–2mol^–1, signifying their non-electrolytic nature. Ni(II) and Cu(II) complexes were paramagnetic, whereas Zn(II) complex was diamagnetic. Electronic spectra show  p - p* and n - p* transitions. The IR spectra of the compounds shows all the desired functional groups at the expected wavenumber. Elemental analyses agreed with the proposed formula of the compounds. The in-vitro antimicrobial, antioxidant and anti-inflammatory potency of the compounds were evaluated, the results revealed that the complexes displayed higher activities than the free dihydrazone. All the compounds exhibited appreciable activities against pathogenic gram positive and gram negative bacteria, harmful fungal species, remarkable radical scavenging activities and significant inflammatory inhibition.