Nickel(II) complexes with polyhydroxybenzaldehyde and O,N,S tridentate thiosemicarbazone ligands: Synthesis, cytotoxicity, antimalarial activity, and molecular docking studies
Document Type
Article
Publication Date
10-15-2021
Abstract
A series of Schiff base metal complexes with the formulations Ni(L1)PPh3]Cl (1), Ni(L2)PPh3]Cl (2), Ni(L3)PPh3] (3), and Ni(L4)PPh3] (4) (where L1 = 2,3,4-trihydroxybenzaldehyde-4-methyl-3-thiosemicarbazone, L2 = 2,3,4-trihydroxybenzaldehyde-4-ethyl-3-thiosemicarbazone, L3 = 2,3,4-trihydroxybenzaldehyde-4-phenyl-3-thiosemicarbazone, and L4 = 2,3,4-trihydroxybenzaldehyde 4-(4-ethylphenyl)-3-thiosemicarbazone) were synthesised. All compounds were characterised using FT-IR, H-1 NMR, and C-13 NMR. The complexes were further characterised with single crystal X-ray diffraction. The complexes are four-coordinated and adopt a square planar geometry, in which the Schiff base ligands bind to the metal centre via their tridentate O,N,S atoms. Ligand L2 and complex 1 showed a higher cytotoxic activity than cisplatin with IC50 5.75 +/- 0.49 and 4.26 +/- 0.29 mu M, respectively when tested against human colorectal carcinoma HCT 116. Besides, complex 3 was found to show a stronger cytotoxic activity with an IC50 7.07 +/- 0.61 AM than its ligand (L3 IC50 9.82 +/- 1.85 mu M) when tested against HCT 116. On the other hand, complexes 2 and 3 showed moderate in vitro antimalarial activity with IC50 9.88 +/- 0.23 and 1.06 +/- 0.01 mu M, respectively. Remarkably, the antimalarial activity increases as the hydrophobicity of the substituent group attached at the N(3) position increases. Through molecular docking simulation, complexes 2 and 3 are predicted to be a minor groove binder with an appreciable DNA binding affinity, suggesting that 2 and 3 exerted their cytotoxicity and antiplasmodial activity probably via their benzaldehyde, triphenylphosphine, aliphatic chain and phenyl moieties interaction with DNA base pairs. (C) 2021 Elsevier B.V. All rights reserved.
Keywords
Thiosemicarbazone, Triphenylphosphine, Cytotoxic activity, Antimalarial activity, Molecular docking
Divisions
Science
Funders
University of Malaya Research Grant[RP033A-17AFR],Ministry of Higher Education & Scientific Research (MHESR)[FRGS-FP006-2015A],MyBrain Scholarship
Publication Title
Journal of Molecular Structure
Volume
1242
Publisher
Elsevier
Publisher Location
RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS