Construction and Docking Studies of Novel Pyrimido[4,5-b]quinolines as Antimicrobial Agents.

In order to develop novel antimicrobial agents, we prepared quinoline bearing pyrimidine analogues 2-7, 8 a-d and 9 a-d and their structures were elucidated by spectroscopic techniques. Furthermore, our second aim was to predict the interactions between the active compounds and enzymes (DNA gyrase and DHFR). In this work, fourteen pyrimido[4,5-b]quinoline derivatives were prepared and assessed for their antimicrobial potential by estimating zone of inhibition. All the screened candidates displayed antibacterial potential with zone of inhibition range of 9-24 mm compared with ampicillin (20-25 mm) as a reference drug. Moreover, the target derivatives 2 (ZI=16), 9 c (ZI=17 mm) and 9 d (ZI=16 mm) recorded higher antifungal activity against C. albicans to that exhibited by the antifungal drug amphotericin B (ZI=15 mm). Finally, the most potent pyrimidoquinoline compounds (2, 3, 8 c, 8 d, 9 c and 9 d) were docked inside DHFR and DNA gyrase active sites and they recorded excellent fitting within the active regions of DNA gyrase and DHFR. These outcomes revealed us that compounds (2, 3, 8 c, 8 d, 9 c and 9 d) could be lead compounds to discover novel antibacterial candidates.

Nanoparticle-laden contact lens for controlled release of vancomycin with enhanced antibiotic efficacy.

Vancomycin is the last resort antibiotic for the treatment of severe bacterial keratitis. Its clinical application is limited due to its hydrophilicity and high molecular weight. To overcome this, this study aims to develop nanoparticles-laden contact lens for controlled ocular delivery of vancomycin. Polyvinyl alcohol (PVA) was used as encapsulant material. The nanoparticles had a negative surface charge and an average size of 147.6 nm. A satisfactory encapsulation efficiency (61.24%) was obtained. The release profile was observed to be slow and sustained, with a release rate of 1.29 µL mg-1 h-1 for 48 h. Five out of 6 test bacteria were suppressed by vancomycin nanoparticles-laden contact lens. Vancomycin is generally ineffective against Gram-negative bacteria and unable to pass through the outer membrane barrier. In this study, vancomycin inhibited Proteus mirabilis and Pseudomonas aeruginosa. Nano-encapsulation enables vancomycin to penetrate the Gram-negative cell wall and further destroy the bacterial cells. On Hohenstein challenge test, all test bacteria exhibited significant reduction in growth when exposed to vancomycin nanoparticles-laden contact lens. This study created an effective and long-lasting vancomycin delivery system via silicone hydrogel contact lenses, by using PVA as encapsulant. The antibiotic efficacy and vancomycin release should be further studied using ocular in vivo models.

Large-scale sonochemical fabrication of a Co3O4-CoFe2O4@MWCNT bifunctional electrocatalyst for enhanced OER/HER performances.

Herein, we have prepared a mixed-phase Co3O4-CoFe2O4@MWCNT nanocomposite through a cheap, large-scale, and facile ultrasonication route followed by annealing. The structural, morphological, and functional group analyses of the synthesized catalysts were performed by employing various characterization approaches such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The resultant samples were tested for bifunctional electrocatalytic activity through various electrochemical techniques: cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). The prepared Co3O4-CoFe2O4@MWCNT nanocomposite achieved a very high current density of 100 mA cm-2 at a lower (290 mV and 342 mV) overpotential (vs. RHE) and a smaller (166 mV dec-1 and 138 mV dec-1) Tafel slope in the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively, compared to Co3O4-CoFe2O4. The excellent electrochemical activity of the as-prepared electrocatalyst was attributed to the uniform incorporation of Co3O4-CoFe2O4 over MWCNTs which provides high redox active sites, a greater surface area, better conductivity, and faster charge mobility. Furthermore, the enhanced electrochemical active surface, low charge-transfer resistance (Rct), and higher exchange current density (J0) of the Co3O4-CoFe2O4@MWCNT ternary composite are attributed to its superior behavior as a bifunctional electrocatalyst. Conclusively, this study demonstrates a novel and large-scale synthesis approach for bifunctional electrocatalysts with a high aspect ratio and abundance of active sites for high-potential energy applications.

Impact of Starch Coating Embedded with Silver Nanoparticles on Strawberry Storage Time.

The strawberry has a very short postharvest life due to its fast softening and decomposition. The goal of this research is to see how well a starch-silver nanoparticle (St-AgNPs) coating affects the physical, chemical, and microbiological qualities of strawberries during postharvest life. Additionally, the effect of washing with running water on silver concentration in coated strawberry fruit was studied by an inductively coupled plasma-optical emission spectrometer (ICP-OES). Furthermore, the shelf-life period was calculated in relation to the temperature of storage. Fourier transform infrared-attenuated total reflectance (FTIR-ATR), UV-Visible, and Transmission Electron Microscopic (TEM) were used to investigate the structure of starch-silver materials, the size and shape of AgNPs, respectively. The AgNPs were spherical, with an average size range of 12.7 nm. The coated samples had the lowest weight loss, decay, and microbial counts as compared to the uncoated sample. They had higher total acidity and anthocyanin contents as well. The washing process led to the almost complete removal of silver particles by rates ranging from 98.86 to 99.10%. Finally, the coating maintained strawberry qualities and lengthened their shelf-life from 2 to 6 days at room storage and from 8 to 16 days in cold storage.

Novel N-bridged pyrazole-1-carbothioamides with potential antiproliferative activity: design, synthesis, in vitro and in silico studies.

Thiazole-substituted pyrazole is an important structural feature of many bioactive compounds, including antiviral, antitubercular, analgesic and anticancer agents. Herein we describe an efficient and facile approach for the synthesis of two series of 36 novel N-bridged pyrazole-1-phenylthiazoles. The antiproliferative activity of a set of representative compounds was evaluated in vitro against different human cancer cell lines. Among the identified compounds, compound 18 showed potent anticancer activity against the examined cancer cell lines. The in silico molecular docking study revealed that compound 18 possesses high binding affinity toward both SK1 and CDK2. Overall, these results indicate that compound 18 is a promising lead anticancer compound which may be exploited for development of antiproliferative drugs.

Facile One-Pot Multicomponent Synthesis of Pyrazolo-Thiazole Substituted Pyridines with Potential Anti-Proliferative Activity: Synthesis, In Vitro and In Silico Studies.

Pyrazolothiazole-substituted pyridine conjugates are an important class of heterocyclic compounds with an extensive variety of potential applications in the medicinal and pharmacological arenas. Therefore, herein, we describe an efficient and facile approach for the synthesis of novel pyrazolo-thiazolo-pyridine conjugate 4, via multicomponent condensation. The latter compound was utilized as a base for the synthesis of two series of 15 novel pyrazolothiazole-based pyridine conjugates (5-16). The newly synthesized compounds were fully characterized using several spectroscopic methods (IR, NMR and MS) and elemental analyses. The anti-proliferative impact of the new synthesized compounds 5-13 and 16 was in vitro appraised towards three human cancer cell lines: human cervix (HeLa), human lung (NCI-H460) and human prostate (PC-3). Our outcomes regarding the anti-proliferative activities disclosed that all the tested compounds exhibited cytotoxic potential towards all the tested cell lines with IC50 = 17.50-61.05 µM, especially the naphthyridine derivative 7, which exhibited the most cytotoxic potential towards the tested cell lines (IC50 = 14.62-17.50 µM) compared with the etoposide (IC50 = 13.34-17.15 µM). Moreover, an in silico docking simulation study was performed on the newly prepared compounds within topoisomerase II (3QX3), to suggest the binding mode of these compounds as anticancer candidates. The in silico docking results indicate that compound 7 was a promising lead anticancer compound which possesses high binding affinity toward topoisomerase II (3QX3) protein.

The Ameliorative Role of Acacia senegal Gum against the Oxidative Stress and Genotoxicity Induced by the Radiographic Contrast Medium (Ioxitalamate) in Albino Rats.

Arabic gum (Acacia senegal, AG) is proven effective antioxidant and cytoprotective agent. The present study was designed to test this notion by investigating the possible role of AG against the radiographic contrast medium (Ioxitalamate, Telebrix-35®, TBX)-induced oxidative stress and genotoxicity. Albino rats were divided into four groups and supplied with either; distilled water, daily 10% (w/v) AG, an intravenous dose of TBX (1600 mg I/kg b.wt) and co-administration of TBX and AG. Rats were sacrificed and blood samples were collected to assess the genotoxicity employing the peripheral blood leucocytes fluorescent double staining; namely the acridine orange/ethidium bromide (AO/EB) staining and alkaline comet assay. Further, chromosomal analyses were done in bone marrow cells. Serum urea and creatinine levels, in addition to malondialdehyde (MDA), nitric oxide (NO), catalase (CAT) and glutathione (GSH) levels in kidney tissues were measured. Liquid chromatography-mass spectrophotometry (LC-MS-MS) was performed to identify the chemical composition of AG extract. Kidney functions, single/double-stranded DNA damage, chromosomal aberrations, mitotic index, MDA and NO levels were significantly (p < 0.001) increased in TBX-treated group compared to the control and AG-treated one. Meanwhile, CAT and GSH activities were significantly diminished and the AG supplementation significantly (p < 0.001) ameliorated these effects compared with the control and AG-treated groups. Five compounds have been identified using GNPS networking including 7,3',4'-Trihydroxyisoflavone, Noscapine, Tetrahydropapaveroline, Costunolide, Hesperidin. In conclusion, results of the present study suggest that AG exerted a protective role against TBX-induced oxidative stress and genotoxicity which may be attributed to the active metabolites in the gum.

New 1,2,3-Triazole-Containing Hybrids as Antitumor Candidates: Design, Click Reaction Synthesis, DFT Calculations, and Molecular Docking Study.

In an effort to improve and achieve biologically active anticancer agents, a novel series of 1,2,3-triazole-containing hybrids were designed and efficiently synthesized via the Cu-catalyzed azide-alkyne cycloaddition (CuAAC) reaction of substituted-arylazides with alkyne-functionalized pyrazole-[1,2,4]-triazole hybrids. The structure geometry of these new clicked 1,2,3-triazoles was explored by density functional theory (DFT) using the B3LYP/6-311++G(d,p) level; also, the potential activity of the compounds for light absorption was simulated by time-dependent DFT calculations (TD-DFT). The antitumor impacts of the newly synthesized compounds were in vitro estimated to be towards the human liver cancer cell line (HepG-2), the human colon cancer cell line (HCT-116), and human breast adenocarcinoma (MCF-7). Among the tested compounds, conjugate 7 was the most potent cytotoxic candidate towards HepG-2, HCT-116, and MCF-7, with IC50 = 12.22, 14.16, and 14.64 µM, respectively, in comparison to that exhibited by the standard drug doxorubicin (IC50 = 11.21, 12.46, and 13.45 µM). Finally, a molecular docking study was conducted within the epidermal growth factor receptor (EGFR) active site to suggest possible binding modes. Hence, it could conceivably be hypothesized that analogies 7, 6, and 5 could be considered as decent lead candidate compounds for anticancer agents.

Enhanced Antioxidant and Cytotoxic Potentials of Lipopolysaccharides-Injected Musca domestica Larvae.

The usage of insects as a sustainable and functional natural products resource is a new promise in complementary and alternative medicine. The present study aimed to investigate the ability of Musca domestica (housefly) larval hemolymph (insect blood) to display the enhanced in vitro antioxidant and cytotoxic effects. The oxidative stress (OS) was elicited by inducing lipopolysaccharides (LPS) treatment as an exogenous stressor. Determination of superoxide dismutase 1 (SOD1), glutathione (GSH), malondialdehyde (MDA) and total antioxidant capacity (TAC), and mRNA and protein expressions of SOD1, was investigated as confirmatory markers of oxidative stress induction. Cytotoxicity on cancerous MCF-7 and normal Vero cells were also evaluated using an MTT assay at 24 h post-injection. The injection of LPS induced a significant (p < 0.05) increase in SOD, GSH and TAC, whereas, the MDA was diminished. Hemolymph was collected from normal and treated larvae after 6, 12 and 24 h. The M. domestica superoxide dismutase (MdSOD1) transcripts were significantly (p < 0.05) upregulated 6 and 12 h post-treatment, while a significant downregulation was observed after 24 h. Western blot analysis showed that MdSOD1 was expressed in the hemolymph of the treated larvae with an increase of 1.2 folds at 6 and 12 h and 1.6 folds at 24 h relative to the control group. LPS-treated larval hemolymphs exhibited significant cytotoxicity with respect to the untreated ones against MCF-7 while Vero cells showed no cytotoxicity for both hemolymphs. The DPPH free radical scavenging activity was examined and a significant antioxidant potential potency was observed at 6 h (50% maximal inhibitory concentration (IC50): 63.3 ± 3.51 µg/mL) when compared to the control M. domestica larval hemolymph (IC50: 611.7 ± 10.41 µg/mL). Taken together, M. domestica larval hemolymph exhibited enhanced antioxidant and consequently increased cytotoxic capacities under stressed conditions.

Adsorption behavior and corrosion inhibitive characteristics of newly synthesized cyano-benzylidene xanthenes on copper/sodium hydroxide interface: Electrochemical, X-ray photoelectron spectroscopy and theoretical studies.

Elegant process for synthesis of 3-(7H-dibenzo[c,h]xanthen-7-yl)benzaldehyde (3), as new starting material to create a set of novel xanthene analogues, 2-(3-(7H-dibenzo[c,h]xanthen-7-yl)benzylidene)malononitrile (4), 3-(3-(7H-dibenzo[c,h]xanthen-7-yl)phenyl)-2-cyanoacrylic acid (5), and Ethyl-3-(3-(7H-dibenzo[c,h]xanthen-7-yl)phenyl)-2-cyanoacrylate (6), was achieved starting with available materials under mild conditions. Various concentrations (ca. 0.1-1.0 mM) of the synthesized cyano-benzylidene xanthene derivatives, namely compounds 3-6, were tested as inhibitors to control copper corrosion in alkaline solutions employing polarization and electrochemical impedance spectroscopy (EIS) measurements. Results revealed that the four studied xanthenes derivatives served as efficient (mixed-type) inhibitors. The inhibition efficiency increased with increase in inhibitor concentration.The inhibition performance of studied compounds varied according to their chemical structures. The best inhibitor, compound (5), achieved a maximum inhibition efficiency of 98.7% (calculated from corrosion current densities) and ~ 95% (estimated from charge-transfer resistance values) at a concentration of 1.0 mM. The morphology of the corroded and inhibited copper surfaces was studied by scanning electron microscopy (SEM). The adsorption of the inhibitor molecules was confirmed by high-resolution X-ray photoelectron spectroscopy (XPS) profiles. XPS data were used to compare the inhibition efficiencies exhibited by studied compounds. The oxidation rate of the Cu surface was found to be frivolous, referring to high inhibition efficiency, only in the presence of inhibitor (5), and Cu0 share is 87% of all copper components. The shares of Cu0 were significantly reduced to 43%, 26% and 20% for inhibitors (3), (4) and (6), respectively. These findings go parallel with the results obtained from electrochemical measurements. The quantum-chemical calculations of the investigated molecules were performed to support electrochemical findings, and their correlations with the inhibition efficiency of the synthesized compounds were discussed.

An Efficient Synthetic Approach Towards Benzo[b]pyrano[2,3-e][1,4]diazepines, and Their Cytotoxic Activity.

In search of unprecedented tri and/or tetrapod pharmacophoric conjugates, a series of 32 new 4-ethyl-1H-benzo[b][1,4]diazepin-2(3H)-ones were synthesized and properly elucidated using MS, IR, NMR, and elemental analysis. In vitro investigation of 11 compounds of this series, using a panel of two human tumor cell lines namely; human breast adenocarcinoma (MCF-7), and human colorectal carcinoma (HCT-116), revealed promising cytotoxic activities. Among all synthesized compounds, analogue 9 displayed maximum cytotoxicity with IC50 values of 16.19 ± 1.35 and 17.16 ± 1.54 µM against HCT-116 and MCF-7, respectively, compared to standard drug doxorubicin.

Design, Synthesis, and Antimicrobial Evaluation of New Annelated Pyrimido[2,1-c][1,2,4]triazolo[3,4-f][1,2,4]triazines.

A series of 34 new pyrimido[2,1-c][1,2,4]triazine-3,4-diones were synthesized and fully characterized using IR, NMR, MS, and microanalytical analysis. In vitro investigation of 12 compounds of this series revealed promising antimicrobial activity of the conjugates 15a and 15f-j that were tagged with electron-withdrawing groups, with sensitivities ranging from 77% to as high as 100% of the positive control. The investigation of antimicrobial activity included Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6535, Pseudomonas aeruginosa ATCC 27853, and Escherichia coli ATCC 8739 (EC), and fungal strains Candida albicans ATCC 10231 and Aspergillus brasiliensis ATCC 16404.

SYNTHESIS AND REACTIVITY OF ENAMINONE OF NAPHTHO[B] 1,4-OXAZINE: ONE POT SYNTHESIS OF NOVEL ISOLATED AND HETEROCYCLE-FUSED DERIVATIVES WITH ANTIMICROBIAL AND ANTIFUNGAL ACTIVITIES.

The synthesis of the multifunctional, hitherto unreported 3-(3-(dimethylamino)acryloyl)-2H-naphtho[1,2- b] [1,4]oxazin-2-one was described and its utility as a versatile building block was demonstrated for the synthesis of some new pyrimidines, pyrazoles, isoxazoles, pyrazolo[a]pyrimidines, triazolo[a]pyrimidines, pyrido[d]pyrimidines, pyrido[d]pyrimidines, piperidines, pyrido[a]benzimidazoles, 2H-pyran-3-carboxamides, benzofurans, naphtho[b]furans and pyrazolo[c] [1,2,4]triazines of potential biological activities. The synthesized compounds were characterized by IR, 1H NMR, 13C NHR and mass spectral data. Some of the compounds were evaluated for antimicrobial activities.

Correction: El Azab, I.H., et al. Microwave-Assisted Synthesis of Novel 2H-Chromene Derivatives Bearing Phenylthiazolidinones and Their Biological Activity Assessment. Molecules 2014, 19, 19648-19664.

The authors wish to revise the Author Affiliation section of the title paper, published in Molecules [1], (doi:10.3390/molecules191219648, website: http://www.mdpi.com/1420-3049/19/12/19648). To recognize the fact that the research described was performed in part at the facilities of Taif University and to acknowledge that institution's generous financial support[...].

Microwave-assisted synthesis of novel 2H-chromene derivatives bearing phenylthiazolidinones and their biological activity assessment.

6-Hydroxy-2-oxo-2H-chromene-4-carbaldehyde (2), 6-chloro-2-oxo-2H-chromene-4-carbaldehyde (3) and 6-hydrazinyl-4-methyl-2H-chromen-2-one (5) were prepared as single-pharmacophore motif key intermediates. Compounds 2, 3 and 5 were incorporated in a series of multicomponent reactions (MCRs), under microwave assistance as well as conventional chemical synthesis processes, to afford a series of three and/or four-pharmacophoric-motif conjugates 8a,b, 11, 13, 16, 17, 19 and 20 in good yields. The newly synthesized compounds were characterized by IR, NMR, 13C-NMR, MS and elemental analyses. Finally the synthesized compounds have been screened for their biological activity whereupon they exhibited remarkable antimicrobial activity on different classes of bacteria and the fungus.