Tumor selective Ru(III) Schiff bases complexes with strong in vitro activity toward cisplatin-resistant MDA-MB-231 breast cancer cells.

Novel ruthenium(III) complexes of general formula Na[RuCl2(L1-3-N,O)2] where L(1-3) denote deprotonated Schiff bases (HL1-HL3) derived from 5-substituted salicyladehyde and alkylamine (propyl- or butylamine) were prepared and characterized based on elemental analysis, mass spectra, infrared, electron spin/paramagnetic resonance (ESR/EPR) spectroscopy, and cyclovoltammetric study. Optimization of five isomers of complex C1 was done by DFT calculation. The interaction of C1-C3 complexes with DNA (Deoxyribonucleic acid) and BSA (Bovine serum albumin) was investigated by electron spectroscopy and fluorescence quenching. The cytotoxic activity of C1-C3 was investigated in a panel of four human cancer cell lines (K562, A549, EA.hy926, MDA-MB-231) and one human non-tumor cell line (MRC-5). Complexes displayed an apparent cytoselective profile, with IC50 values in the low micromolar range from 1.6 ± 0.3 to 23.0 ± 0.1 µM. Cisplatin-resistant triple-negative breast cancer cells MDA-MB-231 displayed the highest sensitivity to complexes, with Ru(III) compound containing two chlorides and two deprotonated N-propyl-5-chloro-salicylidenimine (hereinafter C1) as the most potent (IC50 = 1.6 µM), and approximately ten times more active than cisplatin (IC50 = 21.9 µM). MDA-MB-231 cells treated for 24 h with C1 presented with apoptotic morphology, as seen by acridine orange/ethidium bromide staining, while 48 h of treatment induced DNA fragmentation, and necrotic changes in cells, as seen by flow cytometry analysis. Drug-accumulation study by inductively coupled plasma mass spectrometry (ICP-MS) demonstrated markedly higher intracellular accumulation of C1 compared with cisplatin.

Synthesis, Biological Evaluation and Docking Studies of Benzoxazoles Derived from Thymoquinone.

Thymoquinone (TQ), a natural compound with antimicrobial and antitumor activity, was used as the starting molecule for the preparation of 3-aminothymoquinone (ATQ) from which ten novel benzoxazole derivatives were prepared and characterized by elemental analysis, IR spectroscopy, mass spectrometry and NMR (¹H, 13C) spectroscopy in solution. The crystal structure of 4-methyl-2-phenyl-7-isopropyl-1,3-benzoxazole-5-ol (1a) has been determined by X-ray diffraction. All compounds were tested for their antibacterial, antifungal and antitumor activities. TQ and ATQ showed better antibacterial activity against tested Gram-positive and Gram-negative bacterial strains than benzoxazoles. ATQ had the most potent antifungal effect against Candida albicans, Saccharomyces cerevisiae and Aspergillus brasiliensis. Three benzoxazole derivatives and ATQ showed the highest antitumor activities. The most potent was 2-(4-fluorophenyl)-4-methyl-7-isopropyl-1,3-benzoxazole-5-ol (1f). Western blot analyses have shown that this compound inhibited phosphorylation of protein kinase B (Akt) and Insulin-like Growth Factor-1 Receptor (IGF1R ß) in HeLa and HepG2 cells. The least toxic compound against normal fibroblast cells, which maintains similar antitumor activities as TQ, was 2-(4-chlorophenyl)-4-methyl-7-isopropyl-1,3-benzoxazole-5-ol (1e). Docking studies indicated that 1e and 1f have significant effects against selected receptors playing important roles in tumour survival.

Interaction of Copper(II) Complexes of Bidentate Benzaldehyde Nicotinic Acid Hydrazones with BSA: Spectrofluorimetric and Molecular Docking Approach.

Two copper(II) complexes of 4-chloro- and 4-dimethylaminobenzaldehyde nicotinic acid hydrazones were prepared and characterized by elemental analysis, mass spectrometry, infrared and electron spectroscopy and conductometry. These rare examples of bis(hydrazonato)copper(II) complexes are neutral complex species with copper(II) center coordinated with two monoanionic bidentate O,N-donor hydrazone ligands coordinated in enol-imine form. The interaction of hydrazone ligands and corresponding copper(II) complexes with CT DNA and BSA was investigated. Copper(II) complexes are slightly effective in binding the DNA than pristine hydrazones. The results indicate groove binding or moderate intercalation which are not significantly affected by the nature of substituent at hydrazone ligands. On contrary, affinities of two copper(II) complexes toward BSA significantly differs and depends on the nature of the substituent, however in absence of thermodynamic data difference in nature of binding forces cannot be excluded. The complex bearing electron-withdrawing 4-chloro substituent has larger affinity toward BSA compared to 4-dimethyamino analogue. These findings were theoretically supported by molecular docking study.

Amperometric determination of bonded glucose with an MnO(2) and glucose oxidase bulk-modified screen-printed electrode using flow-injection analysis.

A screen-printed amperometric biosensor based on carbon ink double bulk-modified with MnO(2) as a mediator and glucose oxidase as a biocomponent was investigated for its ability to serve as a detector for bonded glucose in different compounds, such as cellobiose, saccharose, (-)-4-nitrophenyl-beta-d-glucopyranoside, as well as in beer samples by flow-injection analysis (FIA). The biosensor could be operated under physiological conditions (0.1M phosphate buffer, pH 7.5) and exhibited good reproducibility and stability. Bonded glucose was released with glucosidase in solution, and the free glucose was detected with the modified screen-printed electrode (SPE). The release of glucose by the aid of glucosidase from cellobiose, saccharose and (-)-4-nitrophenyl-beta-d-glucopyranoside in solution showed that stoichiometric quantities of free glucose could be monitored in all three cases. The linear range of the amperometric response of the biosensor in the FIA-mode flow rate 0.2mLmin(-1), injection volume 0.25mL, operation potential 0.48V versus Ag/AgCl) extends from 11 to 13,900mumolL(-1) glucose in free form. The limit of detection (3sigma) is 1mumolL(-1) glucose. A concentration of 100mumolL(-1) yields a relative standard deviation of approximately 7% with five injections. These values correspond to the same concentrations of bonded glucose supposed that it is liberated quantitatively (incubation for 2h with glucosidase). Bonded glucose could be determined in beer samples using the same assay. The results corresponded very well with the reference procedure.