Computer-based identification of olive oil components as a potential inhibitor of neirisaral adhesion a regulatory protein.

In silico methods such as molecular docking and molecular dynamic (MD) simulations have significant interest due to their ability to identify the protein-ligand interactions at the atomic level. In this work, different computational methods were used to elucidate the ability of some olive oil components to act as Neisseria adhesion A Regulatory protein (NadR) inhibitors. The frontier molecular orbitals (FMOs) and the global properties such as global hardness, electronegativity, and global softness of ten olive oil components (α-Tocopherol, Erythrodiol, Hydroxytyrosol, Linoleic acid, Apigenin, Luteolin, Oleic acid, Oleocanthal, Palmitic acid, and Tyrosol) were reported using Density Functional Theory (DFT) methods. Among all investigated compounds, Erythrodiol, Apigenin, and Luteolin demonstrated the highest binding affinities (-8.72, -7.12, and -8.24 kcal/mol, respectively) against NadR, compared to -8.21 kcal/mol of the native ligand based on molecular docking calculations. ADMET properties and physicochemical features showed that Erythrodiol, Apigenin, and Luteolin have good physicochemical features and can act as drugs candidate. Molecular dynamics (MD) simulations demonstrated that Erythrodiol, Apigenin, and Luteolin show stable binding affinity and molecular interaction with NadR. Further Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) analyses using the MD trajectories also demonstrated the higher binding affinity of Erythrodiol, Apigenin and Luteolin inside NadR protein. The overall study provides a rationale to use Erythrodiol, Apigenin, and Luteolin in the drug development as anti-adhesive drugs lead. Communicated by Ramaswamy H. Sarma.

Square-wave stripping voltammetry for direct determination of eight heavy metals in soil and indoor-airborne particulate matter.

The application of square-wave voltammetry (SWV) for the determination of eight elements viz. Cd(II), Pb(II), Cu(II), Zn(II), Co(II), Ni(II), Cr(VI), and Mo(VI) in soil and indoor-airborne particulate matter has been examined and optimized. The cathodic and anodic types of the SWV technique were examined for the detection of these metal ions. It was found that the square-wave anodic stripping voltammetry is the conventional technique for the determination of Zn(II), Cd(II), Pb(II), and Cu(II), but square-wave adsorptive cathodic stripping voltammetric method is used for the determination of Co(II), Ni(II), Mo(VI) and Cr(VI). Various experimental parameters, which influenced the response of the mercury film electrode to these metal ions, were optimized. The detection limits of these metal ions were 0.03, 0.4, 0.04, 0.1, 0.15, 0.05, 0.2, and 3.2 microg/kg for Cd(II), Pb(II), Cu(II), Zn(II), Co(II), Ni(II), Cr(VI), and Mo(VI), respectively, with very good accuracy (standard deviation is below 2%). Interference from coexisting ions was successfully investigated. A comparison of analytical data for analyzing real samples was carried out between the SWV method and the graphite furnace atomic absorption spectrophotometric (GFAAS) method. By the standard addition method, the recoveries were 96.6-104% with SD of 0.75-2.5%. The great advantage of SWV is the simplicity, selectivity, sensitivity, and shortening analysis time over the GFAAS method.

Determination of verapamil by adsorptive stripping voltammetry in urine and pharmaceutical formulations.

A sensitive reduction peak of verapamil is obtained by adsorptive stripping voltammetry in 0.01 M phosphate (pH 7.4) at an accumulation time of 30 s. The peak potential is -1.81 V (vs. Ag/AgCl). The peak current is directly proportional to the concentration of verapamil (1x10(-8)-1x10(-6) M), with a 3sigma detection limit of 5x10(-10) M (0.246 ng/ml). The R.S.D. at the 1x10(-7) M level is 1.8%. The interference of some metal ions, and some amino acids, and the application of the method to analysis of urine, and pharmaceutical formulations are described. The method is simple (no extraction), rapid (30 s accumulation time), sensitive (the detection limit of verapamil is 0.491 ng/ml), reproducible(within day R.S.D. of 1.28-1.8%), and suitable for routine analysis of verapamil, urine, and pharmaceutical formulation.

Adsorptive stripping voltammetric determination of antihypertensive agent: diltiazem.

Adsorptive stripping voltammetry was used to determine the antihypertensive agent diltiazem in phosphate buffer (pH 7.0). The adsorptive cathodic peak was observed at -1.72 V vs. Ag/AgCl. The peak response was characterized with respect to pH, preconcentration time, possible interferences, accumulation potential and supporting electrolytes. The obtained results were analyzed and the statistical parameters were calculated. The proposed method was applied to determine the mentioned drug in pharmaceutical formulation (capsule) and urine. The detection limit is 1x10(-8) M (4.5 ng ml(-1)) using 180 s preconcentration time, whereas the lower limit of detection is 6x10(-9) M (2.7 ng ml(-1)).

Cathodic adsorptive stripping voltammetric determination of muscle relaxant: gallamine triethiodide (flaxedil).

A sensitive and simple voltammetric method of analysis is developed for the determination of trace amounts of gallamine triethiode in phosphate media. This method is based on controlled adsorptive preconcentration of the relaxant onto a Hanging Mercury Drop Electrode (HMDE) whereby mercurous iodide salt(s) are formed. The technique used is Cathodic Linear Sweep Stripping Voltammetry (CLSSV). The adsorptive response was evaluated with respect to preconcentration time and potential. As little as 3 x 10(-9) mol dm(-3) i.e. 2.7 ppb flaxedil (proconcentration time 300 seconds) can be determined successfully. The application of this method was tested in the determination of flaxedil in pharmaceutical preparation (ampoules).

Anodic adsorptive stripping voltammetric determination of the anesthetic drug: methohexital sodium.

Methohexital (MS) determination is based on the formation of insoluble mercury salt on a hanging mercury drop electrode after preaccumulation by adsorption. This property was exploited in developing a highly sensitive stripping voltammetric procedure for the determination of the drug. The anodic current of adsorbed compound is measured by linear sweep anodic stripping voltammetry (LSASV), preceded by a period of preconcentration. The effect of various parameters such as supporting electrolyte composition, pH, initial potential, scan rate, accumulation time and ionic strength are discussed to characterize the interfacial and redox behavior. The detection limit was found to be 2x10(-7) M (56.8 ppb) with 180-s accumulation time. The interference of some amino acids, ascorbic acid and some metal ions was investigated. The application of this method was tested in the determination of methohexital in spiked urine samples. The precision of the method is satisfactory with a relative standard deviation of 2.5%.

Cathodic adsorptive stripping voltammetric determination of uranium with potassium hydrogen phthalate.

The adsorption properties of dioxouranium (II)-Phathalate complexes onto hanging mercury drop electrode are exploited in developing a highly sensitive and selective stripping voltammetric procedure for the determination of uranium (VI). The reduction current of adsorbed complex ions of U(VI) was measured by both linear sweep (LSCSV) and differential pulse cathodic stripping voltammetry (DPCSV), preceded by a period of preconcentration onto the electrode surface. As low as 2x10(-9) mol dm(-3) (0.5 mug/l) and 2x10(-8) mol dm(-3) (4.8 mug/l) with accumulation time 240 and 120 s using DPCSV and LSCSV, respectively, have been determined successfully. The relative standard deviation of 2.2% at the 5 ppm level was obtained. The interferences of some metal ions and anions were studied. The application of this method was tested in the determination of uranium in superphosphate fertilizer.

Electroreduction and determination of Pipril (Piperacillin) in both aqueous and biological samples.

The electrochemical behavior of the relatively new antibacterial antibiotic Pipril (Piperacillin) at the dropping mercury electrode is investigated using both direct current polarography (DCP) and differential pulse polarography (DPP). At the hanging mercury electrode (HMDE), the reduction mechanism has been elucidated using cyclic voltammetric technique in the pH range from 2 to 10. The effect of some metal ions, e.g. Cu(II) and Pb(II) has been also tested. Determination of the drug using adsorptive stripping analysis was assessed in both aqueous and urine samples. The effect of the different experimental parameters affecting the drug determination, e.g. pH, supporting electrolyte nature, accumulation potential, accumulation time and other operational parameters are also mentioned. Detection limits of 5 x 10(-9) and 1 x 10(-8)M Pipril in aqueous and urine samples, respectively, are achieved.

Applications in drug analysis of carbon paste electrodes modified by fatty acids.

The oxidation of promethazine as a model compound has been studied by adsorptive stripping voltammetry at carbon paste electrodes (CPE). A modification of the carbon paste matrix with fatty acids allows greater preconcentration of the molecule at the electrode surface. Several fatty acids of different chain length have been tested. The modification of the CPE with lauric acid has been successfully applied in the quantitative analysis of promethazine in standard serum samples. The influence of several parameters affecting the accumulation step has been investigated such as: pH, ionic strength, interfering ions, paste composition. The detection limit in phosphate buffer at pH 9.0 (tacc = 5 min) has been found to be 1 x 10(-10) M.