Molecular docking, structural characterization, DFT and cytotoxicity studies of metal(II) Schiff base complexes derived from thiophene-2-carboxaldehyde and l-histidine

Abstract

Co(II), Ni(II), Cu(II) and Zn(II) complexes of Schiff base ligand (thio-L-his) derived from thiophene-2-carboxaldehyde (thio) with l-histidine (L-his) were synthesised. The thio-L-his and its metal complexes have been optimized and quantum chemical parameters are calculated using density functional theory. Despite several donor sites in the synthesised thio-L-his, the coordination with metal ion occurred through azomethine nitrogen and carboxylate oxygen as evidenced by elemental analyses, fourier transform infrared, mass and nuclear magnetic resonance spectral analysis. The electronic spectral data together with magnetic measurements suggest tetrahedral for Co(II) and Zn(II)-(thio-L-his) and square planar geometries for Ni(II) and Cu(II)-(thio-L-his) complexes, respectively. Molecular docking has been performed to predict the binding energy between thio-L-his and complexes with Epidermal Growth Factor and Cyclooxygenase-2 receptors. The efficiency of metal complexes as promising candidates for the photodegradation of methylene blue has been established in the present study. The comparative in vitro antimicrobial activities against various pathogens with reference to known antibiotics and antioxidant activity against standard control at variable concentrations revealed that the metal complexes show enhanced antimicrobial and free radical scavenging activities as compared to free thio-L-his. In vitro anticancer activity of the Cu(II)-(thio-L-his) was assayed against human ovarian cancer cells, showed that the complex exhibited promising anticancer activity on PA1 cell line.