Phytochemical analysis and Enzyme Inhibition Assay of Aerva javanica for Ulcer

ABSTRACT: BACKGROUND: Aerva javanica (Burm. f.) Juss. ex Schult. (Amaranthacea) is traditionally used for the treatment of wound healings, cough, diarrhoea, ulcer and hyperglycaemia. The current study was aimed to fractionate and isolate bioactive compounds and ultimately to evaluate their anti-ulcereogenic potential. RESULTS: In order to achieve these aims, the fractionation, purifications and then biological potential determination of the isolated compounds was carried out. For purification purpose, initially extraction of the plant material was done with aqueous MeOH in the order of increasing polarity by using solvent-solvent extraction method. Phytochemical analysis revealed the presence of three compounds, 3-hydroxy-4 methoxybenzaldehyde (1), ursolic acid (2) and (E)-N-(4-hydroxy-3-methoxyphenethyl)-3-(4-hydroxy-3-ethoxyphenyl) acryl amide (3). Inhibition of urease activity of various fractions revealed that ethyl acetate fraction showed significant activity (P <0.05) as compared to other fractions. (E)-N-(4-hydroxy-3- methoxyphenethyl)-3-(4-hydroxy-3-ethoxyphenyl) acryl amide (3) showed marked anti ulcer activity (P <0.05). CONCLUSION: These results suggested the mild potential of A. javanica against ulcer.     

Simple,Selective, and Sensitive Spectrophotometric Method for Determination of Trace Amounts of Nickel（Ⅱ）, Copper （Ⅱ）, Cobalt （Ⅱ）, and Iron （Ⅲ） with a Novel Reagent 2-Pyridine Carboxaldehyde Isonicotinyl Hydrazone

A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.     

BC3 Sheet Functionalized with Lithium‐Rich Species Emerging as a Reversible Hydrogen Storage Material

The decoration of a BC₃ monolayer with the polylithiated molecules CLi₄ and OLi₂ has been extensively investigated to study the hydrogen‐storage efficiency of the materials by first principles electronic structure calculations. The binding energies of both lithiated species with the BC₃ substrate are much higher than their respective cohesive energies, which confirms the stability of the doped systems. A significant positive charge on the Li atom in each of the dopants facilitates the adsorption of multiple H₂ molecules under the influence of electrostatic and van der Waals interactions. We observe a high H₂‐storage capacity of 11.88 and 8.70 wt % for the BC₃‐CLi₄ and BC₃‐OLi₂ systems, respectively, making them promising candidates as efficient energy‐storage systems.     

A New Indole Alkaloid from Cleome droserifolia

The phytochemical investigations on Cleome droserifolia resulted in the isolation and characterization of a new indole alkaloid, 5‐hydroxy‐2‐methoxy‐1‐methyl‐1H‐indole‐3‐carbaldehyde ( 1 ). The structure elucidation was carried out on the basis of 1D‐ and 2D‐NMR techniques. In addition to 1 , two known aromatic derivatives, veratrol ( 2 ) and 2‐methoxy‐4‐methylacetophenone ( 3 ), were also obtained. All these compounds were purified by repeated column chromatography of the CH₂Cl₂ fraction obtained from MeOH extract of Cleome droserifolia. The structure of the new compound 1 was finally confirmed by the combined 1D (¹H‐ and ¹³C‐) and 2D (H? C correlations; HMBC and HSQC) NMR and IR spectroscopy, mass spectrometry (MS), and UV absorption spectroscopy techniques. The comparison of the physical and spectroscopic data with those in the literature provided evidence for the structure confirmation of known compounds. All the purified compounds were subjected to urease and α‐glucosidase enzymes inhibition. The results showed that compound 1 was more potent with an IC₅₀ value 11.97±2.067 μg/ml towards urease inhibition, while the activity of α‐glucosidase enzyme was marginal.     

α‐Hydroxymethylation of Pyridines at a Frustrated Lewis Pair Template

The “η²‐formylborane” moiety formed by CO reduction with HB(C₆F₅)₂ at a P/B frustrated Lewis pair template undergoes a hydroxymethylation reaction at the α‐position to nitrogen in pyridine or isoquinoline. The analogous reaction with pyrimidine revealed a mechanism related to the Tschitschibabin reaction.     

A Molecular Tool Targeting the Base-Flipping Activity of Human UHRF1

During DNA replication, ubiquitin-like, containing PHD and RING fingers domains 1 (UHRF1) plays key roles in the inheritance of methylation patterns to daughter strands by recognizing through its SET and RING-associated domain (SRA) the methylated CpGs and recruiting DNA methyltransferase 1 (DNMT1). Herein, our goal is to identify UHRF1 inhibitors targeting the 5′-methylcytosine (5mC) binding pocket of the SRA domain to prevent the recognition and flipping of 5mC and determine the molecular and cellular consequences of this inhibition. For this, we used a multidisciplinary strategy combining virtual screening and molecular modeling with biophysical assays in solution and cells. We identified an anthraquinone compound able to bind to the 5mC binding pocket and inhibit the base-flipping process in the low micromolar range. We also showed in cells that this hit impaired the UHRF1/DNMT1 interaction and decreased the overall methylation of DNA, highlighting the critical role of base flipping for DNMT1 recruitment and providing the first proof of concept of the druggability of the 5mC binding pocket. The selected anthraquinone appears thus as a key tool to investigate the role of UHRF1 in the inheritance of methylation patterns, as well as a starting point for hit-to-lead optimizations.     

Series solution for unsteady axisymmetric flow and heat transfer over a radially stretching sheet

This paper deals with the unsteady axisymmetric flow and heat transfer of a viscous fluid over a radially stretching sheet. The heat is prescribed at the surface. The modelled non-linear partial differential equations are solved using an analytic approach namely the homotopy analysis method. Unlike perturbation technique, this approach gives accurate analytic approximation uniformly valid for all dimensionless time. The explicit expressions for velocity, temperature and skin friction coefficient are developed. The influence of time on the velocity, temperature and skin friction coefficient is discussed.     

CFD analysis of an oscillating wing at various reduced frequencies

The effect of various reduced frequencies has been examined for an oscillating aspect ratio 10 NACA 0015 wing. An unsteady, compressible three‐dimensional (3D) Navier–Stokes code based on Beam and Warming algorithm with the Baldwin–Lomax turbulence model has been used. The code is validated for the study against published experimental data. The 3D unsteady flow field is simulated for reduced frequency values of 0.1, 0.2 and 0.3 for a fixed mean angle of attack position and fixed amplitude. The type of motion is sinusoidal harmonic. The force coefficients, pressure distributions and flow visualization show that at the given conditions the flow remains attached to the wing surface even at high angles of attack with no clear separation or typical light‐to‐deep category of dynamic stall. Increased magnitude of hysteresis and higher gradients are seen at higher reduced frequencies. The 3D effects are even found at midspan locations. In addition, the rate of decrease in lift near the wing tips compared with the wing root is not much like in the static cases. Copyright © 2008 John Wiley & Sons, Ltd.     

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of dextran and dextrin derivatives

Application of matrix-assisted laser desorption/ionization (MALDI) to the analysis of dextran and dextrin derivatives, specifically glucose saccharides, by time-of-flight (TOF) mass spectrometry has been reported. MALDI-TOF analysis was carried out on alpha-, beta- and gamma-cyclodextrin, two O-methylated-beta-cyclodextrins of differing degrees of substitution (DS) and dextrans (a linear glucose saccharide), as pure and doped solutions and as mixtures of two or more of these. Doping was carried out with trace amounts of inorganic salts. The purpose of the analysis of the cyclodextrins was to determine whether they would form inclusion complexes with the various cations added, or whether less specific cation addition/exchange was occurring either prior to desorption or in the gas phase.