A novel biocompatible NiII tethered moiety as a glucose uptake agent and a hit against methicillin-resistant Staphylococcus aureus

Abstract

In the efforts to develop a biocompatible transition metal complex as a drug alike for some of the prevailing non-communicable diseases (NCDs) and communicable diseases (CDs), a novel binuclear NiII compound [{NiII(hpdbal-sbdt)}2] (2) has been synthesized by the reaction of Ni(OAc)2.4H2O and H2hpdbal-sbdt (1) [1 is a dibasic tridentate ONS2− donor Schiff base ligand obtained by the condensation of 2-hydroxy-5-(phenyldiazenyl)benzaldehyde (Hhpdbal) and S-benzyldithiocarbazate (Hsbdt)]. Both ligand 1 and compound 2 were structurally characterized in the solid and solution state using various spectroscopic techniques like ATIR, 1H NMR, 13C NMR, TGA, FESEM, EDS and CHNS analysis. The antidiabetic activity of H2hpdbal-sbdt (1) and [{NiII(hpdbal-sbdt)}2] (2) were assessed using 2-NBDG uptake assay. The assay results showed 85% and 95% of fluorescent glucose uptake by insulin resistant HePG2 cells treated with compounds 1 and 2 respectively. The 2-NBDG uptake by the cells treated with the compound 2 was observed to be comparable to the standard antidiabetic drug metformin. Compounds 1 and 2 were also tested against five bacterial and two fungi strains in order to evaluate pathogen killing activity. Compound 2 showed significant inhibitory action towards the methicillin-resistant Staphylococcus aureus (MRSA) strain with an MIC value of 2 μg/mL whereas the ligand 1 was found to be inactive. Furthermore, the interactive nature of compound 2 with a model serum carrier protein bovine serum albumin (BSA) was studied using a multi-spectroscopic approach which provided an insight into the nature and extent of binding, conformational changes and the quenching of amino acid residues of the protein.