Three New Acrylic Acid Derivatives from Achillea mellifolium as Potential Inhibitors of Urease from Jack Bean and α-Glucosidase from Saccharomyces cerevisiae

(1) Background: Achillea mellifolium belongs to a highly reputed family of medicinal plants, with plant extract being used as medicine in indigenous system. However, limited data is available regarding the exploitation of the medicinal potential of isolated pure compounds from this family; (2) Methods: A whole plant extract was partitioned into fractions and on the basis of biological activity, an ethyl acetate fraction was selected for isolation of pure compounds. Isolated compounds were characterized using different spectroscopic techniques. The compounds isolated from this study were tested for their medicinal potential using in-vitro enzyme assay, coupled with in-silico studies; (3) Results: Three new acrylic acid derivatives (1–3) have been isolated from the ethyl acetate fraction of Achillea mellifolium. The characterization of these compounds (1–3) was carried out using UV/Vis, FT-IR, 1D and 2D-NMR spectroscopy (¹H-NMR, ¹³C-NMR, HMBC, NOESY) and mass spectrometry. These acrylic acid derivatives were further evaluated for their enzyme inhibition potential against urease from jack bean and α glucosidase from Saccharomyces cerevisiae, using both in-silico and in-vitro approaches. In-vitro studies showed that compound 3 has the highest inhibition against urease enzyme (IC₅₀ =10.46 ± 0.03 μΜ), followed by compound 1 and compound 2 with percent inhibition and IC₅₀ value of 16.87 ± 0.02 c and 13.71 ± 0.07 μΜ, respectively, compared to the standard (thiourea-IC₅₀ = 21.5 ± 0.01 μΜ). The investigated IC₅₀ value of compound 3 against the urease enzyme is two times lower compared to thiourea, suggesting that this compound is twice as active compared to the standard drug. On the other hand, all three compounds (1–3) revealed mild inhibition potential against α-glucosidase. In-silico molecular docking studies, in combination with MD simulations and free energy, calculations were also performed to rationalize their time evolved mode of interaction inside the active pocket. Binding energies were computed using a MMPBSA approach, and the role of individual residues to overall binding of the inhibitors inside the active pockets were also computed; (4) Conclusions: Together, these studies confirm the inhibitory potential of isolated acrylic acid derivatives against both urease and α-glucosidase enzymes; however, their inhibition potential is better for urease enzyme even when compared to the standard.     

Antioxidant and Gastroprotective Activity of Suaeda fruticosa Forssk. Ex J.F.Gmel

Suaeda fruticosa Forssk. Ex J.F.Gmel is traditionally used for inflammatory and digestive disorders, as a carminative, and for diarrhea. This plant is widely distributed in Asia, Africa, and the Mediterranean region. Aqueous methanolic extract of S. fruticosa (Sf.Cr) was prepared and screened for phytoconstituents through qualitative and GC-MS analysis. Quantification of total phenolic and flavonoid contents was performed, while antioxidant capacity was determined by DPPH, CUPRAC, FRAP, and ABTS assays. The gastroprotective activity was assessed in an ethanol-induced ulcer model. Gastric secretory parameters and macroscopic ulcerated lesions were analyzed and scored for ulcer severity. After scoring, histopathology was performed, and gastric mucus contents were determined. Oral pre-treatment of Sf.Cr demonstrated significant gastroprotection. The gastric ulcer severity score and ulcer index were reduced while the %-inhibition of ulcer was increased dose-dependently. The Sf.Cr significantly elevated the pH of gastric juice, while a decrease in total acidity and gastric juice volume was observed. Histopathology demonstrated less oedema and neutrophil infiltration in gastric mucosa of rats pre-treated with the Sf.Cr in comparison to ethanol-intoxicated animals. Furthermore, the gastric mucus contents were increased as determined by alcian blue binding. Sf.Cr showed marked gastroprotective activity, which can be attributed to antioxidant, antisecretory, and cytoprotective effects.     

Effect of ion beam irradiation on palladium (II) acetyl acetonate dispersed in polymer matrix

Composites, containing different concentrations of palladium (II) acetylacetonate in polymethyl methacrylate (PMMA) matrix were prepared by vigorous mixing. PMMA was prepared by solution polymerization technique. The composites were irradiated with a 120 MeV Ni¹⁰⁺ beam at two different fluences of 1×10¹¹ and 5×10¹² ions/cm² to study ion-induced effects on their dielectric, structural properties and surface morphology. AC electrical properties of these samples were studied in the frequency range 100 Hz to 10 MHz. The dielectric permittivity/loss shows frequency dependent behavior and it obeys the universal law of dielectric (i.e. ?α f ^n?1) for pristine and irradiated samples at high frequency. The crystalline size and crystallinity of the composites were studied by X-ray diffraction analysis. Decrease in peak intensity after irradiation signifies the amorphization which is also responsible for decrease in T _g as obtained by means of differential scanning calorimetry measurement. Fourier transform infrared spectra also support this result. Surface roughness increases upon irradiation as observed from scanning electron microscopy.     

Structural, electronic, and optical properties of ZnOl_xSex alloys using first-principles calculations

The structural, electronic, and optical properties of binary ZnO, ZnSe compounds, and their ternary ZnOl_xSex alloys are computed using the accurate full potential linearized augmented plane wave plus local orbital （FP-LAPW ＋ lo） method in the rocksalt （B 1） and zincblende （B3） crystallographic phases. The electronic band structures, fundamental energy band gaps, and densities of states for ZnO1_xSex are evaluated in the range 0 〈 x 〈 1 using Wu-Cohen （WC） generalized gradient approximation （GGA） for the exchange-correlation potential. Our calculated results of lattice parameters and bulk modulus reveal a nonlinear variation for pseudo-binary and their ternary alloys in both phases and show a considerable deviation from Vegard＇s law. It is observed that the predicted lattice parameter and bulk modulus are in good agreement with the available experimental and theoretical data. We establish that the composition dependence of band gap is semi-metallic in B1 phase, while a direct band gap is observed in B3 phase. The calculated density of states is described by taking into account the contribution of Zn 3d, O 2p, and Se 4s, and the optical properties are studied in terms of dielectric functions, refractive index, reflectivity, and energy loss function for the B3 phase and are compared with the available experimental data.     

Synthetic approaches toward stilbenes and their related structures

Compounds belonging to the stilbene family have gained remarkable significance in pharmaceutical as well as material chemistry. The current review covers the various synthetic approaches for the syntheses of stilbene scaffold and related structures over last 30 years. In addition, this review also highlights the role of stilbene intermediates used in the synthesis of important molecules with diverse applications in the field of pharmaceutics and material science.     

Annealing of ion-implanted Ga0.47In0.53As

We have investigated annealing of ion-implanted GaInAs using transmission electron microscopy. We have found that the best condition for the post-implantation anneals for GalnAs is a 30 second anneal at a temperature of 700–800°C. This produces a material similar in character to the untreated GaInAs. Anneals for longer than 30 seconds produce crystal defects becoming increasingly complex with time for similar temperatures.     

Surface Functionalization of Magnetite Nanoparticles with Multipotent Antioxidant as Potential Magnetic Nanoantioxidants and Antimicrobial Agents

Functionalized magnetite nanoparticles (Fe₃O₄) were prepared using the coprecipitation method followed by functionalization with a multipotent antioxidant (MPAO). The MPAO was synthesized and analyzed using FTIR and NMR techniques. In this study, the functionalized nanoparticles (IONP@AO) were produced and evaluated using the FTIR, XRD, Raman, HRTEM, FESEM, VSM, and EDX techniques. The average determined particle size of IONP@AO was 10 nanometers. In addition, it demonstrated superparamagnetic properties. The magnitude of saturation magnetization value attained was 45 emu g⁻¹. Virtual screenings of the MPAO’s potential bioactivities and safety profile were performed using PASS analysis and ADMET studies before the synthesis step. For the DPPH test, IONP@AO was found to have a four-fold greater ability to scavenge free radicals than unfunctional IONP. The antimicrobial properties of IONP@AO were also demonstrated against a variety of bacteria and fungi. The interaction of developed nanoantioxiants with biomolecules makes it a broad-spectrum candidate in biomedicine and nanomedicine.     

New insights into the transition pathway from nonspecific to specific complex of DNA with Escherichia coli integration host factor

To elucidate the nature of the transition-state ensemble along the reaction pathway from a nonspecific protein-DNA complex to the specific complex, we have carried out measurements of DNA bending/unbending dynamics on a cognate DNA substrate in complex with integration host factor (IHF), an architectural protein from E. coli that bends its cognate site by approximately 180 degrees . We use a laser temperature jump to perturb the IHF-DNA complex and monitor the relaxation kinetics with time-resolved FRET measurements on DNA substrates end-labeled with a FRET pair. Previously, we showed that spontaneous bending/kinking of DNA, from thermal disruption of base-pairing/-stacking interactions, may be the rate-limiting step in the formation of the specific complex (Kuznetsov, S. V.; Sugimura, S.; Vivas, P.; Crothers, D. M.; Ansari, A. Proc. Natl. Acad. Sci. USA 2006, 103, 18515). Here, we probe the effect of varying [KCl], which affects the stability of the complex, on this rate-limiting step. We find that below approximately 250 mM KCl, the observed relaxation kinetics are from the unimolecular bending/unbending of DNA, and the relaxation rate kr is independent of [KCl]. Above approximately 300 mM KCl, dissociation of the IHF-DNA complex becomes significant, and the observed relaxation process includes contributions from the association/dissociation step, with kr decreasing with increasing [KCl]. The DNA bending step occurs with a positive activation enthalpy, despite the large negative enthalpy change reported for the specific IHF-DNA complex (Holbrook, J. A.; Tsodikov, O. V.; Saecker, R. M.; Record, M. T., Jr. J. Mol. Biol. 2001, 310, 379). Our conclusion from these studies is that in the uphill climb to the transition state, the DNA is kinked, but with no release of ions, as indicated by the salt-independent behavior of k(r) at low [KCl]. Any release of ions in the unimolecular process, together with conformational changes in the protein-DNA complex that facilitate favorable interactions and that contribute to the negative enthalpy change, must occur as the system leaves the transition state, downhill to the final complex.     

Cu(OTf)2/Cu-catalyzed four-component reaction: a facile synthesis of α-alkoxytriazoles via click chemistry

Aldehyde, alcohol, azide, and alkyne undergo smooth coupling by means of acetal formation, azidation, and a subsequent ‘click reaction’ in the presence of copper(II) triflate and copper metal in acetonitrile to furnish α-alkoxy-1,2,3-triazoles in good yields. The method provides a convenient route to prepare a wide range of triazoles in a one-pot operation via a four-component reaction.     

Elemental Analysis of Cement by Calibration-Free Laser Induced Breakdown Spectroscopy (CF-LIBS) and Comparison with Laser Ablation – Time-of-Flight – Mass Spectrometry (LA-TOF-MS), Energy Dispersive X-Ray Spectrometry (EDX), X-Ray Fluorescence Spectroscopy (XRF), and Proton Induced X-Ray Emission Spectrometry (PIXE)

The purpose of the present study is to determine the elemental composition of Pakistani cement brands using calibration-free laser induced breakdown spectroscopy (CF-LIBS) and to compare the obtained results with the other analytical techniques such as, laser ablation – time-of-flight – mass spectrometry (LA-TOF-MS), energy dispersive X-ray spectrometry (EDX), X-ray fluorescence spectroscopy (XRF) and proton induced X-ray emission spectrometry (PIXE). Compositional results reveal that all the cement brands are mainly composed of calcium, silicon, iron, aluminum, magnesium, potassium, sodium, titanium, lithium and strontium with varying concentrations. The compositions obtained by LIBS and LA-TOF-MS are in good agreement with results obtained by the other standard techniques and demonstrate the potential use of LIBS for the online monitoring of industrial cement production.