Anticancer Potential of Dendritic Poly(aryl ether)-Substituted Polypyridyl Ligand-Based Ruthenium(II) Coordination Entities.

This paper studies the anticancer potency of dendritic poly(aryl ether)-substituted polypyridyl ligand-based ruthenium(II) coordination entities. The dendritic coordination entities were successfully designed, synthesized, and characterized by different spectral methods such as Fourier transform infrared (FTIR), 1H and 13C- NMR, and mass spectrometry. Further, to understand the structure and solvation behavior of the coordination entities, we performed all-atom molecular dynamics (MD) simulations. The behavior, configuration, and size of the coordination entities in DMSO and water were studied by calculating the radius of gyration (Rg) and solvent-accessible surface area (SASA). The MTT assay was used to assess the in vitro cytotoxicity of all of the coordination entities against cancerous A549 (lung cancer cells), MDA MB 231 (breast cancer cells), and HepG2 (liver cancer cells) and was found to be good with comparable IC50 values with respect to the standard drug cisplatin. The coordination entities exhibited dose dependence, and the highest activity was shown against HepG2 cell lines in comparison to the other cancer cell lines. In addition, fluorescence staining studies, such as AO/EB, DAPI, and cell death analysis by PI staining, were performed on the coordination entities to understand the apoptosis mechanism. Furthermore, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) assays confirmed apoptosis in cancer cells via the mitochondrial pathway. The DNA fragmentation assay was done followed by molecular docking analysis with DNA executed to strengthen and support the experimental observations.

Identification, ADMET evaluation and molecular docking analysis of Phytosterols from Banaba (Lagerstroemia speciosa (L.)Pers) seed extract against breast cancer.

Lagerstroemia speciosa (L.) Pers., (Lythraceae), commonly called Banaba, is a native plant of Southeast Asia and is widely used in the treatment of diabetics, obesity, kidney diseases, and other inflammatory disorders. L. speciosa consists of several phytoconstituents like glycosides, flavones, corosolic acid, ellagic acids, triterpenes, tannins, which are reported to be present in leaves, stem, flowers, fruit, bark, and roots. This paper presents an investigation on the binding interaction of phytosterols derivatives identified from the ethanolic extract of Lagerstroemia speciosa seeds against breast cancer target protein. The ethanolic extracts Lagerstroemia speciosa seeds were analyzed via GC-MS for the identification of their chemical constituent. In silico methods are adopted to predict ADME parameters, pharmacokinetic properties, drug-likeliness, and acute toxicity of the identified phytosterols molecules. Molecular docking analysis of the phytosterols was performed against three breast cancer targets. A total of 29 compounds were identified from the extract by GC-MS analysis, among which four phytosterols derivatives namely cholesterol margarate, 7-dehydrodiosgenin, Stigmastan-3,5-diene, and γ-sitosterol have been considered for the present study. These phytosterols are identified as non-toxic, non-carcinogenic, and non-mutagenic. Molecular docking studies reveal the extent of molecular interaction with breast cancer targets. The outcomes of the investigation suggest that the phytosterols obtained from the ethanolic seed extract of Lagerstroemia speciosa could act as a promising candidate against breast cancer.

Micellar effect on the photophysics of heteroleptic ruthenium(II)-phenanthrolinedisulfonato complexes.

Luminescent heteroleptic ruthenium(II) complexes of type RuLn X(3-n) [L = 1,10-phenanthroline (phen), X = 4,7 diphenyl phenanthroline disulfonate, (dpsphen) n = 0,1,2,3] were synthesized and their photophysical properties investigated in homogeneous and cationic (CTAB), anionic (SDS) and nonionic (Triton X-100) micelles. The luminescent quantum yield and lifetime of the complexes were found to increase in the presence of micellar media and on the introduction of a disulfonate ligand into the coordination sphere. Both electrostatic and hydrophobic interactions play an important role in the micellar media. Thus, by changing the nature of the ligands and the medium, we were able to tune the photophysical properties of Ru(II) complexes.

Photoinduced electron transfer reactions of ruthenium(II) phenanthroline complexes with dimethylaniline in aqueous and micellar media.

Four [Ru(NN)(3)](2+) complexes (NN = polypyridine) with ligands of varying hydrophobicity with different charges +2, 0 and -4 were synthesized. The photophysics and photoinduced electron transfer reactions of these Ru(II)-complexes with dimethylaniline (DMA) as the quencher have been studied in aqueous medium and ionic and non-ionic micellar medium. The extent of binding of the complexes with the surfactant interface is evident from the calculated binding constant values (K). Dimethylaniline (DMA) being a neutral quencher, the hydrophobic and electrostatic interactions competing with one another and their combined effect with the surfactants were reported by observing the quenching rate constant (k(q)) values. The formation of anilinium cation radical in transient absorption spectrum confirms the excited state electron transfer reactions of ruthenium(II) complexes with dimethylaniline. The calculated rate constant values (k(q)) are in good agreement with the experimental k(q) values giving quantitative evidence for the bimolecular reductive quenching rate constant for the complexes with DMA. Pseudophase ion exchange model is successfully applied to analyse the quenching data.

Photoinduced electron transfer reactions of ruthenium(II)-complexes containing amino acid with quinones.

With the aim of mimicking, at basic level the photoinduced electron transfer process in the reaction center of photosystem II, ruthenium(II)-polypyridyl complexes, carrying amino acids were synthesized and studied their photoinduced electron transfer reactions with quinones by steady state and time resolved measurements. The reaction of quinones with excited state of ruthenium(II)-complexes, I-V in acetonitrile has been studied by luminescence quenching technique and the rate constant, k(q), values are close to the diffusion controlled rate. The detection of the semiquinone anion radical in this system using time-resolved transient absorption spectroscopy confirms the electron transfer nature of the reaction. The semiclassical theory of electron transfer has been successfully applied to the photoluminescence quenching of Ru(II)-complexes with quinones.