Synthesis, characterization and in vitro biological activity of new zinc(II) complexes of the nonsteroidal anti‐inflammatory drug sulindac and nitrogen‐donor ligands

Abstract

Metal carboxylate compounds with nitrogen‐ and/or oxygen‐donor ligands with various carboxylate coordination modes, monodentate, bidentate and bridging bidentate, have been shown to be important from biological and chemical aspects. Five zinc ion binary compounds, diaqua‐bis‐(2‐((E)‐5‐fluoro‐2‐methyl‐1‐(4‐(methylsulfinyl)benzylidene)‐1H–inden‐3‐yl)acetato)zinc(II) (1), aqua‐bis‐(2‐((E)‐5‐fluoro‐2‐methyl‐1‐(4‐(methylsulfinyl)benzylidene)‐1H–inden‐3‐yl)acetato)pyridin‐2‐aminezinc(II) (2), (2‐((E)‐5‐fluoro‐2‐methyl‐1‐(4‐(methylsulfinyl)benzylidene)‐1H–inden‐3‐yl)acetato) pyridin‐2‐ylmethanaminezinc(II) (2‐((E)‐5‐fluoro‐2‐methyl‐1‐(4‐(methylsulfinyl)benzylidene)‐1H–inden‐3‐yl)acetate) (3), bis‐(2‐((E)‐5‐fluoro‐2‐methyl‐1‐(4‐(methylsulfinyl)benzylidene)‐1H–inden‐3‐yl)acetato)‐1,10‐phenanthrolinezinc(II) (4) and bis‐(2‐((E)‐5‐fluoro‐2‐methyl‐1‐(4‐(methylsulfinyl)benzylidene)‐1H–inden‐3‐yl)acetato)‐1,10‐phenanthrolinezinc(II) (5), have been prepared and fully characterized. In addition, the complexes were evaluated for their antibacterial activity using the in vitro agar diffusion method against two Gram‐positive (Staphylococcus epidermidis, Staphylococcus aureus) and two Gram‐negative (Bordetella, Escherichia coli) bacteria and yeast species (Saccharomyces and Candida). Complex 5 showed reasonable activity against yeast. All compounds showed greater antibacterial activity against Gram‐positive than Gram‐negative bacteria. Results indicated that the efficiency of complex 5 in preventing the formation of β‐hematin was 67.6%. The efficiency of chloroquine as a standard drug was reported as 93%. Furthermore, the phosphatase activity of the Zn(II) complexes was studied and results indicated an effect of the zinc complexes on phosphatase activity.