DNA binding, DNA cleavage and HSA interaction of several metal complexes containing N-(2-hydroxyethyl)-N′-benzoylthiourea and 1,10-phenanthroline ligands

Abstract

Four novel ternary metal complexes of the type [M(Phen)(L1)2)] [phen = 1,10-phenanthroline, L1 = N-(2-hydroxyethyl)-N'-benzoylthiourea, M = Ni(II)(1), Co(II) (2), Cu(II) (3), Pd(II) (4)] were synthesized. The organic ligands and their corresponding organometallic complexes have been characterized using UV-vis absorption spectroscopy, element analysis, infrared radiation spectroscopy and fluorescence spectra. DNA binding and cleavage studies of these complexes were conducted in detail. In vitro DNA-binding properties were studied by electronic absorption spectra and fluorescence spectra methods. The results indicate that all of the ternary metal complexes can efficiently bind to DNA via intercalation mode. The DNA-binding constants for all ternary compounds are around 4 × 10(6) M(-1). The binding propensity of the complexes to human serum albumin (HSA) was also investigated. Agarose gel electrophoresis study revealed that the metal complexes could cleave super-coiled pBR322 DNA to a nicked form in the absence of external agents. In vitro anti bacterial studies show that copper complex has weak antibacterial activities. Copper complex exhibits a better biological activity among all complexes. This study provides a new perspective and evaluation on the role and importance of the effect factors on the medicinal properties of benzoylthiourea compounds. Synchronous fluorescence spectra of HSA (10 μM) as a function of concentration of the complexes 1-4.

In Vitro Biomolecular Interaction Studies and Cytotoxic Activities of Newly Synthesised Copper(II) Complexes Bearing 2‐Hydroxynaphthaldehyde‐Based Thiosemicarbazone

“…A concomitant decrease in the absorption intensity (hypochromism) without shifting the position of the peak was observed. The hypochromism is possibly due to intercalation which causes the interaction between the electronic states of the intercalating moiety and that of the DNA base …”

3,3-Bis(2-hydroxyethyl)-1-(4-methylbenzoyl)thiourea: crystal structure, Hirshfeld surface analysis and computational study

“…While the motivations for preparing metal complexes of benzoylthioureas are varied, e.g. for anion recognition and as catalysts (Saeed et al, 2014;Zhang & Schreiner, 2009;Nishikawa, 2018), there is continuing interest in exploring their biological potential as coordination of these ligands to metals generally enhances their biological efficacy, such as anti-cancer (Peng et al, 2016;Barolli et al, 2017;Jeyalakshmi et al, 2019), anti-microbial (Gemili et al, 2017;Binzet et al, 2018;Saeed et al, 2018) and anti-mycobacterium tuberculosis (Plutín et al, 2016) activities. The present study was motivated by these applications and by previous structural studies (Gunasekaran et al, 2017; and the known catalytic applications of their cobalt complexes (Gunasekaran, Jerome et al, 2012).…”

Biological evaluation, DNA/protein‐binding aptitude of novel dibenzosuberene appended palladium (II)‐thiourea complexes

“…The hypochromism and hyperchromism are considered as spectral evidence for DNA structural changes when DNA interacts with other molecules. [32,33] In the intercalation process, the ℼ* orbital of the intercalated moieties could couple with ℼ orbitals of the base pairs, thus decreasing the ℼ → ℼ* transition energies, which results in hypochromism. The results of the titrations clearly showed a regular decrease in the absorption intensity (hypochromism) besides a small red shift for all complexes (1)(2)(3)(4).…”

“…The intercalated complex involving a strong stacking interaction between an aromatic chromophore and the base pairs of DNA changes the double helix structure of the latter and thus usually results in hypochromism. [32,37] The free energy (ΔG) was calculated by using equation ΔG = −RT ln K b .The observed values of ΔG were in the range of −7.25 to −6.17 kcal mol −1 , showing the spontaneity of complex-DNA interaction. [34] Moreover, the existence of a red shift is an indication of the stabilization of the DNA duplex.…”