Synthesis, spectroscopic characterization, thermal behaviour, in vitro antimicrobial and anticancer activities of novel ruthenium tricarbonyl complexes containing monodentate V‐shaped Schiff bases

Exploring the effect of Ru(II) arene complexes on cytotoxicity upon co-ligand variation and loading on amine-functionalized silica nanoparticles

To overcome the undesirable side effects and acquired resistance associated with platinum-based chemotherapeutics, scientists are searching for alternative strategies involving novel metal-based compounds with improved pharmacological properties. Ruthenium complexes have emerged as prospective candidates to combat side effects and improve the selectivity of anticancer agents. In this work, a benzimidazole-based chelating ligand, HL (4-(1H-naphth[2,3-d]imidazol-2-yl)-1,3-benzenediol) with O and N donor atoms, was synthesized and used for complexation with ruthenium to obtain three Ru(II) arene complexes represented by [Ru(η6-p-cym)(L)Cl], [Ru(η6-p-cym)(L)(PPh3)]+ and [Ru(η6-p-cym)(L)(PTA)]+ (where p-cym = p-cymene, PPh3 = triphenylphosphine and PTA = 1,3,5-triaza-7-phosphaadamantane). The synthesized complexes were characterized using spectroscopic techniques. UV-Vis absorption spectroscopy and LC-MS were used to study the stability of the complexes in biological medium. Their lipophilicity was studied by calculating the partition coefficient in n-octanol and water. The complexes showed significant binding with biomolecules like albumin proteins and nucleic acids. All the complexes were found to be cytotoxic, with complex [Ru(η6-p-cym)(L)PPh3]PF6 exhibiting the highest anticancer activity. The mechanism of anticancer activity was attributed to the ability of the complexes to induce apoptosis and generate reactive oxygen species (ROS). The complexes also exhibited antimetastatic properties. Furthermore, complex [Ru(η6-p-cym)(L)PPh3]PF6 was loaded onto amine-functionalized mesoporous silica nanoparticles which led to an increase in its cytotoxic activity.

Design, synthesis, biomedical investigation, DFT calculation and molecular docking of novel Ru(II)-mixed ligand complexes

A novel series of bioactive water-soluble mononuclear Ru(II)-mixed ligand complexes of 2,2'-bipyridyl and V-shaped Schiff base ligands were synthesized and structurally characterized. Biomedical activities of Ru(II) complexes have been tested in view of antioxidant activities, interaction with calf thymus DNA (CT-DNA), and anticancer performance. The optimized structure of these complexes has been further supported by density functional theory (DFT) calculations. Further, validation of the interaction studies of some complexes was accomplished by carrying out molecular docking studies with DNA using molecular operating environment (MOE) software are reported.Communicated by Ramaswamy H. Sarma.

Molecular Design, Spectroscopic, DFT, Pharmacological, and Molecular Docking Studies of Novel Ruthenium(III)-Schiff Base Complex: An Inhibitor of Progression in HepG2 Cells

A novel ruthenium(III)-pyrimidine Schiff base was synthesized and characterized using different analytical and spectroscopic techniques. Molecular geometries of the ligand and ruthenium complex were investigated using the DFT-B3LYP level of theory. The quantum global reactivity descriptors were also calculated. Various biological and molecular docking studies of the complex are reported to explore its potential application as a therapeutic drug. Cytotoxicity of the complex was screened against cancer colorectal (HCT116), breast (MCF-7 and T47D), and hepatocellular (HepG2) cell lines as well as a human normal cell line (HSF). The complex effectively inhibited the tested cancer cells with variable degree with higher activity towards HepG2 (IC₅₀ values were 29 μM for HepG2, 38.5 μM for T47D, 39.7 μM for HCT, and 46.7 μM for MCF-7 cells). The complex induced apoptosis and cell cycle arrest in the S phase of HepG2 cells. The complex significantly induced the expression of H2AX and caspase 3 and caspase 7 gene and the protein level of caspase 3, as well as inhibited VEGF-A and mTOR/AKT, SND1, and NF-kB gene expression. The molecular docking studies supported the increased total apoptosis of treated HepG2 cells due to strong interaction of the complex with DNA. Additionally, the possible binding interaction of the complex with caspase 3 could be responsible for the elevated activity of caspase 3-treated cells. The score values for the two receptors were -3.25 and -3.91 kcal/mol.

Recent Advances in Schiff Base Ruthenium Metal Complexes: Synthesis and Applications

This review concentrates on recent developments in ruthenium Schiff bases, whose steric and electronic characteristics can be manipulated easily by selecting suitable condensing aldehydes or ketones and primary amines, and their metal complexes. Ruthenium metal-based complexes and Schiff base ligands are rapidly becoming conventionally considered for biological applications (antioxidant, anticancer, antimicrobial), in catalysis, in functional materials, in sensors, and as pigments for dyes. Ruthenium complexes exhibit a broad variety of activities concerning simple Schiff base ligands. This may be due to the octahedral bonding of both Ru(II) and Ru(III) complexes, which acquire an extended reservoir of a three-dimensional framework, providing the potential for an elevated degree of site selectivity for binding to their biological targets. This review provides an overview of this field, and intends to highlight both ligand design and synthetic methodology development, as well as significant applications of these metal complexes. In this review, we summarize our work on the development of ruthenium complexes, which was performed over the last few years.

Structural elucidation, theoretical investigation, biological screening and molecular docking studies of metal(II) complexes of NN donor ligand derived from 4-(2-aminopyridin-3-methylene)aminobenzoic acid

Complexes of 4-(((2-aminopyridin-3-yl)methylene)amino)benzoic acid ligand with cobalt(II) (1), nickel(II) (2), copper(II) (3), zinc(II) (4) and palladium(II) (5) are synthesized and characterized by using different spectroscopic methods like, UV-Visible, infrared, ¹H, ¹³C NMR, molar conductance, ESR and elemental analysis. Quantum chemical computations were made using DFT (density functional theory), B3LYP functional and 6-31+ +G(d,p)/SDD basis set in order to determine optimized structure parameters, frontier molecular orbital parameters and NLO properties. Based on DFT and experimental evidence, the complexes ensured that the octahedral geometry have been proposed for complexes 1, 2 and 4, square planar for complexes 3 and 5. All the complexes showed only residual molar conductance values and hence they were considered as non-electrolytes in DMF. In addition, the anti-proliferative activity of the compounds was evaluated against different human cancer cell lines (IMR-32, MCF-7, COLO205, A549, HeLa and HEK 293) and cisplatin is used as a reference drug. Compounds 1 and 4 showed remarkable cytotoxicity in five cancer cell lines tested except MCF-7. Also, the compounds were examined for their in vitro antimicrobial and scavenging activities. The molecular docking results are well corroborated with the experimental anticancer activity results.