Surface layering in ionic liquids: an X-ray reflectivity study

The surface structure and thermodynamics of two ionic liquids, based on the 1-alkyl-3-methylimidazolium cations, were studied by X-ray reflectivity and surface tensiometry. A molecular layer of a density approximately 18% higher than that of the bulk is found to form at the free surface of these liquids. In common with surface layering in liquid metals and surface freezing in melts of organic chain molecules, this effect is induced by the lower dimensionality of the surface. The concentrations of the oppositely charged ions within the surface layer are determined by chemical substitution of the anion. The temperature-dependent surface tension measurements reveal a normal, negative-slope temperature dependence. The different possible molecular arrangements within the enhanced-density surface layer are discussed.     

Fatty acid Langmuir films on liquid mercury: X-ray and surface tension studies

The structure and phase behavior of liquid-mercury-supported molecular films of fatty acids (CH3(CH2)n-2COOH, denoted CnOOH) were studied for molecular lengths 7 < or = n < or = 24, by surface tensiometry and X-ray methods. Two qualitatively different film structures were found, depending on coverage. For high coverage, the film consists of a monolayer of roughly surface-normal molecules, showing a pressure-dependent sequence of structures similar, though not identical, to that of the corresponding water-supported Langmuir films. At low coverage, phases consisting of surface-parallel molecules are found, not observed on the aqueous subphases employed to date. In this range, a two-dimensional (2D) gas followed by a single and, for 14 < or = n < or = 24, also by a double layer of surface-parallel molecules is found as coverage is increased. Depending on chain length, the flat-lying phases have a crystalline 2D-ordered, a smectic-like 1D-ordered, or a disordered in-plane structure consisting of molecular dimers. The structure and thermodynamics of the films are discussed.     

Structure of mercaptobiphenyl monolayers on mercury

The molecular-scale structure and phase behavior of single-component Langmuir films of 4'-methyl-4-mercaptobiphenyl (MMB) and 4'-perfluoromethyl-4-mercaptobiphenyl (FMMB) on mercury were studied using surface tensiometry, grazing incidence X-ray diffraction, and X-ray reflectivity. At low coverages, a condensed but in-plane disordered single layer of surface-parallel molecules is found for both compounds. At high coverages, both compounds exhibit in-plane-ordered phases of standing-up molecules. For MMB, the biphenyl core dominates the structure, yielding a centered-rectangular unit cell with an area A(x) of 21.8 A(2)/molecule, with molecules tilted by approximately 14 degrees from the surface normal in the nearest-neighbor direction, and a coherence length xi of >1000 A for the crystalline domains. For FMMB, the perfluoromethyl group dominates the structure, yielding a hexagonal unit cell with untilted molecules, an area A(x) of 24.2 A(2)/molecule, and a much smaller xi of approximately 110 A. The structure is discussed in comparison with self-assembled monolayers of MMB on crystalline Au(111) and similar-length alkanethiolate SAMs on Au(111) and on mercury. The differences in the structure are discussed and traced to the differences in the substrate's surface structure, and in the molecular cross section and rigidity.     

Wetting, mixing, and phase transitions in Langmuir-Gibbs films

Millimolar bulk concentrations of the surfactant cetyltrimethylammonium bromide (CTAB) induce spreading of alkanes, H(CH(2))(n)H (denoted C(n)) 12< or =n< or =21, on the water surface, which is not otherwise wet by these alkanes. The novel Langmuir-Gibbs film (LGF) formed is a liquidlike monolayer comprising both alkanes and CTAB tails. Upon cooling, an ordering transition occurs, yielding a hexagonally packed, quasi-2D crystal. For 11< or =n< or =17 this surface-frozen LGF is a crystalline monolayer. For 18< or =n< or =21 the LGF is a bilayer with a crystalline, pure-alkane, upper monolayer, and a liquidlike lower monolayer. The phase diagram and film structure were determined by x-ray, ellipsometry, and surface tension measurements. A thermodynamic theory accounts quantitatively for the observations.     

Determination of hypericin content in Hypericum triquetrifolium Turra (Hypericaceae) growing wild in Jordan

Hypericin content of methanolic extracts of dried flowers, leaves, stems, and roots of Hypericum triquetrifolium (Turra) were determined by HPLC. Conversion of protohypericin to hypericin was achieved by exposing samples to light for 30 min immediately before HPLC analysis. External standard calibration was used to quantify hypericin. Leaves showed the highest hypericin content of 0.36% w/w. Total aerial parts contained 0.43% w/w of hypericin. The relatively high hypericin content of the H. triquetrifolium in this study encourages the introduction, cultivation, and biological evaluation of hypericum specie in Jordan.     

Discovery of Novel Epoxyketone Peptides as Lipase Inhibitors

Obesity is the most common nutritional disorder in the developed world and is associated with important comorbidities. Pancreatic lipase (PL) inhibitors play a key role in the metabolism of human fat. A series of novel epoxyketones peptide derivatives were investigated for their pancreatic lipase inhibitory activity. The epoxyketone moiety is a well-known reactive electrophile group that has been used as part of proteasome inhibitors in cancer therapy, and it is widely believed that these are very selective for targeting the proteasome active site. Here we investigated various peptide derivatives with an epoxide warhead for their anti-lipase activity. The assessment of these novel epoxyketones was performed by an in-house method that we developed for rapid screening and identification of lipase inhibitors using GC-FID. Herein, we present a novel anti-lipase pharmacophore based on epoxyketone peptide derivatives that showed potent anti-lipase activity. Many of these derivatives had comparable or more potent activity than the clinically used lipase inhibitors such as orlistat. In addition, the lipase appears to be inhibited by a wide range of epoxyketone analogues regardless of the configuration of the epoxide in the epoxyketone moiety. The presented data in this study shows the first example of the use of epoxyketone peptides as novel lipase inhibitors.     

Synthesis and Some Reactions of Coumarin‐3‐yl Crotononitrile Derivatives

Several new coumarinyl crotononitriles, 2a‐i, coumarinyl cinnamocoumarines 3a,b, 4‐amino‐3‐(substituted)‐3,4‐dihydrocoumarin 4a‐c and 9a‐c, nicotinic acid derivatives 10a,b and 4‐ethoxy‐3‐substituted‐3,4‐dihydrocoumarins 11, were synthesized from 3‐acetyl and/or 3‐benzoyl coumarin. The behavior of coumarin‐3‐yl crotononitriles 2a,b toward some electrophilic and nucleophilic reagents have been described with the aim of preparing some new heterocyclic compounds.     

Green synthesis of zinc oxide nanoflowers using Hypericum triquetrifolium extract: characterization,antibacterial activity and cytotoxicity against lung cancer A549 cells

Zinc oxide nanoparticles have attracted significant interest in recent years due to their unique multifunctional chemical and physical properties along with their biological activities. This study demonstrated for the first time the biogenetic synthesis of zinc oxide nanoparticles by utilization of the methanolic extract of Hypericum triquetrifolium (HT). The obtained nanoparticles (HT-ZnO) were characterized by ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The shape of the resulted nanoparticles is fusiform nanoflowers with an average hydrodynamic size of 275.46 ± 0.20 nm and a zeta potential of −8.23 ± 0.26 mV. SEM micrographs revealed that HT-ZnO nanoflowers have a multi-process structure in which one of the processes is large and the others have similar smaller dimensions. The synthesized nanoflowers have an average length of 312.28 ± 78.93 nm and the tip of its processes has a width of 48.69 ± 9.71 nm. The antimicrobial activity of HT-ZnO nanoflowers was performed using microbroth dilution format. It showed a bactericidal mode of action against Gram-positive Staphylococcus aureus and Enterococcus faecalis with MIC/MBC values of 20 μg/mL and 5 μg/mL, respectively. MTT assay had revealed that HT-ZnO nanoflowers caused a dose-dependent decline in the viability of A549 adenocarcinomic human alveolar basal epithelial cells with an IC₅₀ value of 20.45 μg/mL. The effect of HT-ZnO nanoflowers on the migration and colony formation abilities against the same cells was evaluated as well. In conclusion, zinc oxide nanoflowers were successfully synthesized using methanolic extract of H. triquetrifolium. The resulting particles showed a bactericidal effect against Gram-positiveS. aureus and E. faecalis and a cytotoxic activity against A549 cells.     

Antioxidant activity and total phenolic content of aqueous and methanolic extracts of Jordanian plants: an ICBG project

As part of an International Cooperative Biodiversity Groups (ICBG) program to study Jordan's biodiversity, the relative levels of antioxidant activity and the total phenolic content of aqueous and methanolic extracts of a total of 95 plant species, all of Jordanian origin and those collected at random, have been measured. The total phenolic content of aqueous and methanolic extracts of the investigated plant species ranged from 4.4 to 78.3 mg and from 2.1 to 52.8 mg gallic acid equivalents g(-1) dry weight, respectively, while the total antioxidant capacity ranged from 20.0 to 916.7 and from 15.1 to 915.6 micromol Trolox equivalents g(-1) dry weight, respectively. Based on this collection, approximately 5% of assayed plants showed high levels of antioxidant activity. There was a significant linear correlation between antioxidant activity and total phenolic content for aqueous and methanolic extracts, suggesting that phenolic compounds were the predominant antioxidant components in the investigated plant species. Interestingly, a few of the collected plants had high-antioxidant activity yet "low" phenolic content includes Ceratonia siliqua and Viscum cruciatum. These plants may serve as sources of antioxidants with new chemotypes.     

Discovery of Phenylcarbamoylazinane-1,2,4-Triazole Amides Derivatives as the Potential Inhibitors of Aldo-Keto Reductases (AKR1B1 & AKRB10): Potential Lead Molecules for Treatment of Colon Cancer

Both members of the aldo-keto reductases (AKRs) family, AKR1B1 and AKR1B10, are over-expressed in various type of cancer, making them potential targets for inflammation-mediated cancers such as colon, lung, breast, and prostate cancers. This is the first comprehensive study which focused on the identification of phenylcarbamoylazinane-1, 2,4-triazole amides (7a–o) as the inhibitors of aldo-keto reductases (AKR1B1, AKR1B10) via detailed computational analysis. Firstly, the stability and reactivity of compounds were determined by using the Guassian09 programme in which the density functional theory (DFT) calculations were performed by using the B3LYP/SVP level. Among all the derivatives, the 7d, 7e, 7f, 7h, 7j, 7k, and 7m were found chemically reactive. Then the binding interactions of the optimized compounds within the active pocket of the selected targets were carried out by using molecular docking software: AutoDock tools and Molecular operation environment (MOE) software, and during analysis, the Autodock (academic software) results were found to be reproducible, suggesting this software is best over the MOE (commercial software). The results were found in correlation with the DFT results, suggesting 7d as the best inhibitor of AKR1B1 with the energy value of −49.40 kJ/mol and 7f as the best inhibitor of AKR1B10 with the energy value of −52.84 kJ/mol. The other potent compounds also showed comparable binding energies. The best inhibitors of both targets were validated by the molecular dynamics simulation studies where the root mean square value of <2 along with the other physicochemical properties, hydrogen bond interactions, and binding energies were observed. Furthermore, the anticancer potential of the potent compounds was confirmed by cell viability (MTT) assay. The studied compounds fall into the category of drug-like properties and also supported by physicochemical and pharmacological ADMET properties. It can be suggested that the further synthesis of derivatives of 7d and 7f may lead to the potential drug-like molecules for the treatment of colon cancer associated with the aberrant expression of either AKR1B1 or AKR1B10 and other associated malignancies.