Synthesis, antibacterial activity and DNA interactions of lanthanide(III) complexes of N(4)-substituted thiosemicarbazones

Abstract

This paper reports the synthesis and detailed characterization of six novel lanthanide complexes of La(III), Eu(III) and Nd(III) with N(4)-substituted thiosemicarbazones derived from the 2-carboxybenzaldehyde. The IR, 1H-NMR and 13C-NMR spectroscopic studies confirmed the coordination of the thiocarbonyl (C=S), azomethine (C=N) and carboxylate (COO-) groups to the metal centers, and the carboxylate was coordinated in a bidentate manner. The elemental and thermal analyses suggest that lanthanide complexes were formed in 1:2 molar ratios (metal:ligand). The molar conductivity values confirmed the non-electrolytic nature of the complexes. The interaction of these complexes with calf thymus DNA (CT-DNA) was investigated by UV absorption and viscosity measurements. It was found that the Eu(III) and Nd(III) complexes could roll along the DNA strands through groove interactions. Furthermore, lanthanide complexes could promote the oxidative cleavage of plasmid pBR322 in a high-oxidative stress environment. Finally, the Schiff base ligands (L) and their complexes were evaluated for their antibacterial activities against gram-positive and gram-negative bacteria using a microdilution procedure. The results indicate that the lanthanide complexes exhibit more potent antibacterial activity than the free ligands.

Cu(II) and Ni(II) Complexes with New Tridentate NNS Thiosemicarbazones: Synthesis, Characterisation, DNA Interaction, and Antibacterial Activity

“…In addition to the determination of the melting points of N (4)-phenylthiosemicarbazide (m.p. : 140–141°C) and N (4)-(4-chlorophenyl)thiosemicarbazide (mp: 165–167°C), the characteristic infrared bands of each compound were assigned in accordance with previous reports [14, 27, 28]. The condensation of the latter compounds with 2-acetylpyrazine, followed by acid hydrolysis, afforded the TSCs as crystalline solids in greater than 80% yields (Schemes 1(E) and 1(F)).…”

Anticancer activity of pyrimidodiazepines based on 2-chloro-4-anilinoquinazoline: synthesis, DNA binding and molecular docking

“…The binding properties of the compounds 14g and 16c with highly polymerized and lyophilized calf thymus DNA (ctDNA, type I, bers, Sigma-Aldrich, Lot#SLBJ8916V PCode 1001817527) have been studied using electronic absorption experiments and viscosity measurements, following standard methodologies and procedures previously adopted by our laboratory. 57 Stock solutions of ctDNA were prepared using a solution of Tris (10 mM) and EDTA (1 mM) in deionized water (pH ¼ 7.5) and stored at À5 C. Concentration was determined spectrophotometrically at 25 C, using 3 260 ¼ 6600 L cm À1 mol À1 as molar extinction coefficient and measuring the absorbance at 260 nm. The purity of ctDNA was determined by monitoring the absorbance ratio at 260 nm to that at 280 nm.…”

In Vitro Evaluation of the Potential Pharmacological Activity and Molecular Targets of New Benzimidazole-Based Schiff Base Metal Complexes

“…The interaction studies of the compounds obtained with highly polymerized and lyophilized calf thymus DNA (CT-DNA from Sigma Aldrich) were carried out with electronic absorption experiments, following the methodology reported in the literature [ 77 ]. The DNA solutions had an A 260 /A 280 ratio between 1.7 and 1.9, indicating that the DNA was free of RNA and proteins.…”