Synthesis and characterization of a Schiff base Cobalt (III) complex and assessment of its anti-cancer activity

Abstract

Cobalt (III) tris(azido)-2-Morpholino-N-(1-(2-pyridyl)ethylidene)ethanamine complex was synthesized, characterized and evaluated for in vitro anticancer activities. The chemical structure of the compound was assessed by elemental analysis, single crystal x-ray crystallography, FT-IR and UV-Visible spectroscopy. Schiff base molecule acts as tridentate ligand to form two five-membered chelate rings with the Co(III) ion. In the crystal structure three meridionally arranged nitrogen atoms from three azide ligands complete a distorted octahedral geometry around the metal center. The distortion from an ideal octahedron is evident from the cisoid [82.45(5)-96.03(5)⁰] and transoid [168.62(5)-177.62(5)⁰] angles. The azide groups are almost linear [175.65(15)-179.22(14)⁰] whereas the Co-N-N-N linkages are significantly bent [114.33(9)-123.13(9)⁰]. The novel cobalt(III) compound showed efficient anti-cancer activity against MCF-7 breast cancer cells. The compound was screened by MTT assay and was found to inhibit the growth of MCF-7 cells in a dose-dependent manner (IC50=2.80±0.02 μg/ml). The free ligand and free metal MTT assay showed no significant inhibition activities at a concentration even higher than the compound which confirmed that chelation of ligand with cobalt ion was significant for the activity of this novel compound. The cobalt compound activated caspase-3 via the intrinsic mitochondrial apoptotic pathway resulting in induces apoptosis on MCF-7 cell line.

Keywords: Co(III) compound; x-ray crystallography; MCF-7; Apoptosis; Anticancer activity