Structurally characterized Ni(II) complex exhibiting potent anti-Candida activity: Biomolecular interaction mechanism and in silico ADMET insights

Abstract

The current study reports the synthesis, structural interpretation, biomolecular interaction, and antifungal appraisal of a Ni(II) Schiff base complex demonstrating effective activity against Candida albicans. The complex, formulated as [Ni(L)₂], features a NiN₄O₂ coordination environment and was synthesized using the ligand L, [4-bromo-2-((3-(methylamino)propylimino)methyl)phenol], derived from the condensation of 5-bromo-2-hydroxybenzaldehyde with N-methylpropane-1,3-diamine, followed by complexation with nickel(II) chloride in methanol. The complex was comprehensively characterized by FTIR, ¹H NMR, ESI–MS, and single-crystal X-ray diffraction analyses. Crystallographic studies expose that the complex crystallizes in a monoclinic system with a slightly distorted octahedral geometry around the Ni(II) center. UV-Vis and fluorescence spectroscopic investigations point out strong CT-DNA binding via a groove mode of binding and static quenching interactions with bovine serum albumin (BSA). Moreover, in silico ADMET analysis predicts favourable pharmacokinetic properties, validating the experimental findings that reveal prominent antifungal efficiency of the complex against fluconazole-resistant Candida albicans. Besides, the in silico findings with experimental cytotoxicity evaluation using a mammalian cell model (HEK-293T), provides direct biological evidence of biocompatibility at functionally relevant concentrations. This experimental validation strengthens the overall safety assessment and mitigates the uncertainty associated with computational ADMET analysis for coordination compounds.