Synthesis, Antimicrobial Activities of New Sulfonamidobenzoxazoles and Molecular Docking Studies on Escherichia coli TEM-1 β-Lactamase

β-Lactam antibiotics are frequently used for treatment of multi-drug resistant microbial infections and the most common mechanism of resistance against these antibiotics is bacterial β-lactamase production. Herein, we reported the design, synthesis and in vitro antimicrobial activities of some new 2-substituted-5-(2,4-dinitrophenylsulfonamido)benzoxazole derivatives. Compounds TN1, TN2, and TN3 were found to be significantly active against E. coli isolate which contains extended spectrum β-lactamase enzyme at the MIC value of 8 µg mL–1 and that is 4-fold higher than the reference drug ampicillin. We performed molecular docking studies into active site of Escherichia coli TEM-1 β-lactamase enzyme in order to predict the protein-ligand interactions. According to the docking results, compounds TN1, TN2, and TN3 showed strong interactions between the important active site residues which are responsible for the catalytic mechanism of TEM-1 β-lactamase enzyme and a good correlation is found with the experimental data. This work is licensed under a Creative Commons Attribution 4.0 International License

Pharmacophore-Based Virtual Screening of Novel GSTP1-1 Inhibitors

Glutathione transferase enzymes play an important role in metabolism and detoxification of numerous xenobiotics, electrophilic drugs, environmental carcinogens, and products of oxidative stress in living organisms. Human GST P1-1 is the most prevalent isoform of the mammalian cytosolic GSTs and this enzyme participates in a particular role in one of the mechanisms of the development of resistance in cancer cells toward the administration of anticancer agents in chemotherapy. Herein, pharmacophore analysis were performed using bioactive conformation of the known inhibitor of GSTP1-1, ethacrynic acid (pdb ID:2GSS). Phase module of the Schrödinger suite was used to generate pharmacophore hypothesis. Molecules with same pharmacophoric features were screened from among the commercially available compounds in the ZINC database and ligand filtration was also done to obtain an efficient collection of hit molecules by employing Lipinski “rule of five” using Qikprop module. As a result, some of the compounds obtained from this study, could be the promising inhibitors of hGSTP1-1 enzyme

Discovery of New DNA Topoisomerase II Inhibitors using Structure Based Virtual Screening Method

DNA topoisomerases are proved therapeutic targets of anticancer and antibacterial drugs. Structures of topoisomerase–DNA and inhibitor ternary complexes have revealed the exact binding sites and mechanisms of topoisomerase poisons. There are two isoforms of Human Topoisomerase II; α and β. Both of them perform similar functions and their levels differ depending on the replicative activity and type of tissue. Topo IIα is preferentially expressed in proliferating cells. Thus selective Topo IIα inhibitors have been of particular interest in cancer therapy, as they may represent a more targeted approach to highly proliferative cells. In this study, we use structure based virtual screening method with molecules which are commercially available in the ZINC database. Docking studies were performed by Glide module available in Schrödinger software, Ligand filtration was also done to obtain an efficient collection of hit molecules by employing Lipinski “rule of five” and pharmacokinetic properties of the compounds were tested using Qikprop module. From approximately ten thousand compounds from Zinc database it was possible to select 4 top chemical structures with good inhibiting profile for topo II, with suitable ADME/Tox properties, thus comp. 1-4 could be the promising inhibitors of human topo IIα enzyme

Antiproliferative and genotoxic activities in L929 and HeLa cell lines, mutagenic effects in Salmonella strains of novel benzoxazole derivatives

Some novel fused heterocyclic compounds of 2,5-disubstituted-benzoxazole derivatives, which were previously synthesized by our group, were investigated for their mutagenic properties on Salmonella typhimurium TA 98 and TA 100 strains, cytotoxic activity in L929 and HeLa cell lines by Sulforhodamine B (SRB) cytotoxicity test, and genotoxic potentials in the comet assay. By using Ames/Salmonella assay in the presence of S9 fraction, B22 (5-nitro-2-(p-nitrobenzyl)benzoxazole) was found to be mutagenic in both S. typhimurium TA98 and TA100 strains at all tested doses. IC50 values which were evaluated by SRB cytotoxicity assay revealed that B11 (2-(p-nitrobenzyl)benzoxazole) (IC50 = 99.16 µM) was the most anti-proliferative compound on HeLa cancer cells. Compounds were also tested for their genotoxicity by using comet assay, and it was found that all the compounds had DNA-damaging genotoxic activity on HeLa cells. The comet assay results showed that B11 produced DNA damage at lower concentrations than the other compounds tested on HeLa cancer cells. The results obtained from all the tests suggest that B11 could be a good candidate as a new anticancer agent. © 2016, Colegio de Farmaceuticos de la Provincia de Buenos Aires. All rights reserved

A study on antiproliferative and genotoxic potentials in L929 and HeLa cell lines - the mutagenic activities in Salmonella strains of novel 2,5-disubstituted-benzoxazole derivatives

41st FEBS Congress on Molecular and Systems Biology for a Better Life -- SEP 03-08, 2016 -- Kusadasi, TURKEYWOS: 000383616900256FEB

Synthesis of novel 2-[4-(4-substitutedbenzamido/phenylacetamido) phenyl]benzothiazoles as antimicrobial agents

Abstract A new series of 2-[4-(4-substitutedbenzamido/ phenylacetamido)phenyl] benzothiazole derivatives (6a-k) were synthesized and evaluated for antibacterial and antifungal activities against Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli with their drug-resistant isolates and a yeast Candida albicans. Microbiological results indicated that the compounds possessed a broad spectrum of activity against the tested microorganisms at minimum inhibitory concentration (MIC) values between 100 and 6.25 lg/ml. Compounds 6d and 6k exhibited significant antibacterial activity showing 6.25 lg/ml MIC values against drugresistant S. aureus and P. aeruginosa isolates, respectively

FTIR, Raman and DFT studies on 2-[4-(4-ethylbenzamido)phenyl] benzothiazole and 2-[4-(4-nitrobenzamido)phenyl]benzothiazole supported by differential scanning calorimetry

Altunayar-Unsalan, Cisem/0000-0001-6479-4223; Bolelli, Kayhan/0000-0002-2179-997X; Unsalan, Ozan/0000-0001-5736-7530; ARI, HATICE/0000-0002-8560-9776WOS: 000541166500016[No abstract available

Synthesis, biological evaluation and 2D-QSAR analysis of benzoxazoles as antimicrobial agents

Abstract A new series of 5(or 6)-nitro/amino-2-(substituted phenyl/benzyl)benzoxazole derivatives (1ae1m, 2ae2l) were synthesized and evaluated for antibacterial and antifungal activities against Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Candida albicans and their drug-resistant isolate. Microbiological results indicated that the synthesized compounds possessed a broad spectrum of activity against the tested microorganisms at MIC values between >400 and 12.5 mg/ml. The results against B. subtilis, P. aeruginosa, drug-resistant B. subtilis, drug-resistant E. coli, and C. albicans isolate for these kinds of structures are quite encouraging. The 2D-QSAR analysis of a set of newly and previously synthesized benzoxazoles tested for growth inhibitory activity against B. subtilis ATCC 6633 was performed by using the multivariable regression analysis. The activity contributions for substituent effects of these compounds were determined from the correlation equation for predictions of the lead optimization