Purpose: To synthesize a series of mixed ligand-metal complexes and to evaluate their alkaline
phosphatase inhibitory capacities, antioxidant potential and antimicrobial activities.
Method: Mixed ligand-metal complexes of Zn (II), Ni (II), Co (II), Cu (II), omeprazole and 8-hydroxyquinoline were synthesized. The ligand-metal complexes were characterized by various
physicochemical techniques, including elemental analysis, magnetic susceptibility, scanning electron
microscope (SEM), mass spectrometry (EI-MS), ultraviolet-visible (UV-Vis) spectrophotometry, Fourier
transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (
1H-NMR) and conductance
studies. The new compounds were also investigated for their alkaline phosphatase (ALPs) inhibition,
2,2’-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging and antimicrobial activities.
Results: Spectroscopic studies revealed the chemical composition of synthesized compounds as well
as the bidentate bonding behavior of the coordinating ligands with metal ions. Conductance
measurement suggested that the metal complexes were non-electrolytes. Ni(II) complex exhibited
antioxidant activity (30.48 ± 0.32 μM) higher than those of BHT (standard) and other complexes.
Stronger inhibition of ALPs by Ni (II) mixed ligand complex compared to the other complexes was
evident. The synthesized compounds showed moderate to very good antimicrobial activity against
bacterial strains, i.e.,
Escherichia coli
,
Pseudomonas aeruginosa
,
Klebsiella pneumoniae
,
Actinomyces viscosus
,
Staphylococcus aureus
,
Bacillus subtilis
; as well as against the fungal strains,
Candida albicans
,
Aspergillus flavus
and
Aspergillus niger
.
Conclusion: All the mixed ligand complexes demonstrate higher antioxidant, ALPs-inhibitory and
antimicrobial activities than their corresponding ligands. This indicates their therapeutic potential as
future drug candidates for the concerned diseases.
