Synthesis, biological activity and molecular modeling of a new series of condensed 1,2,4-triazoles.

A ring transformation of 6-methyl-7H[1,2,4]triazolo [4,3-b][1,2,4] triazepine-8(9H)-ones (thiones) in the presence of acetic anhydride give rise to a new series of 17 condensed 1,2,4-triazole derivatives (1-17). Plausible mechanisms are proposed and show the formation of a beta fused ß-lactam moiety. The compounds were tested for their (i) inhibitory potential on digestive enzymes (α-amylase and α-glucosidase), and (ii) antioxidant activity using radical scavenging (DPPH and ABTS radicals) and ferric reducing power assays. The compounds showed interesting and promising antidiabetic activities compared to the reference drug Acarbose. Molecular docking study has been carried out to determine the binding mode interactions between these derivatives and the targeted enzymes. The results showed the strength of intermolecular hydrogen bonding in ligand-receptor complexes as an important descriptor in rationalizing the observed inhibition results. Moreover, molecular dynamics simulations are also performed for the best protein-ligand complex to understand the stability of small molecule in a protein environment. To shed light on the antioxidant activity of the synthesized compounds and the mechanism involved in DPPH free radical, DFT calculations were performed at the B3P86/6-311++G(d,p) level using the polarizable continuum model. The effect of aprotic solvent on bond dissociation enthalpies (BDEs) is investigated by calculating and comparing BDEs of 1 in methanol and dimethylsulfoxide as solvents using PCM. The obtained results show that the mechanism of action depends on the basic skeleton and the presence of substituted functional groups in these derivatives. BDEs are found to be slightly influenced by the aprotic solvent of less than 0.01 kcal/mol compared with those obtained in methanol.

Synthesis and structure elucidation of novel salophen-based dioxo-uranium(VI) complexes: In-vitro and in-silico studies of their DNA/BSA-binding properties and anticancer activity.

The synthesis and characterization of three dioxo U(VI) complexes, [UO2(L1)(OH2)], [UO2(L2)DMF], and [UO2(L2)DMSO], [L1]2- = 1,1'-(4-methyl-1,2-phenylenebis (nitrilomethylidyne))di-2-naphtholate: [L2]2- = 1,1'-(o-phenylenebis (nitrilomethylidyne)) di-2-naphtholate, are reported. Elemental analysis, FT-IR, 1HNMR, UV-Vis spectroscopy, molar conductivity and single crystal X-ray diffraction were used to characterize the complexes. It was found that the complexes adopt a distorted pentagonal bipyramidal coordination geometry. The interaction of the synthesized complexes with DNA and bovine serum albumin was thoroughly investigated using both experimental and theoretical studies. UV-Vis absorption and fluorescence quenching techniques were applied to determine the binding parameters as well as the mechanism of the interaction of each complex with DNA and the protein. The results obtained suggested that interaction of the complexes with DNA occurred through partial intercalation into the minor grooves of DNA with binding constants in the range of 0.661 × 105-1.56 × 105 M-1. In addition, interaction of the complexes with bovine serum albumin quenched the fluorescence emission of the tryptophan residues of the protein binding constants and thermodynamic parameters were obtained from the fluorescence quenching experiments at different temperatures. The values of binding constants revealed moderate interactions between the synthesized complexes and the protein suggesting that this protein could act as a suitable vehicle for transportation of the compounds. The results of molecular docking confirmed those of the experimental studies. The anticancer properties of the title complexes were also evaluated through a study of the in vitro cytotoxicity of the compounds against the HT-29 and MCF-7 cancer cell lines and the DPSC normal cell line using an MTT assay.