A simple method for extracting both active oily and water soluble extract (WSE) from Nigella sativa (L.) seeds using a single solvent system

The current study provides a way of extraction for both active NSO and WSE from Nigella sativa seeds using 98% methanol. About 1?kg of ground seeds was macerated by 1:2.5 w/v (g/mL) for 72?hours. After rotary evaporation and 7 days of continuous drying and chilling at 50 and 4?°C, NSO and WSE were obtained at the same instant. Solubility tests of 24 solvents and 11 thin layer chromatographic analyses while 2, 2-diphenyl-1-picrylhydrazyl free radical scavenging assay of NSO (73.66) , WSE (33.32) and NSO?+?WSE (78.22) against ascorbic acid (IC50?=?4.28?mg/mL) was performed. WSE was found to be highly soluble in water and 5% NaOH exhibiting the same Rf value of 0.95 for EtOH:DMSO (9:1) against the honey. WSE has revealed more than twofold higher anti-oxidant activity than others. Formulation of WSE with Tualang honey may provide better targeted hydrophilic drug delivery systems.     

Can quantum-mechanical calculations yield reasonable estimates of hydrogen-bonding acceptor strength? The case of hydrogen-bonded complexes of methanol

The thermodynamics and some vibrational properties of hydrogen-bonded complexes of methanol with 23 hydrogen-bond acceptors (HBAs) have been determined in CCl(4) by FTIR spectrometry. The experimental sample contains carbon, nitrogen, oxygen, sulfur, fluorine, and chlorine organic bases and covers an energetic range of 13 kJ mol(-1) in the basicity scale (-ΔG), 22 kJ mol(-1) in the affinity scale (-ΔH), and 400 cm(-1) in the spectroscopic scale (Δν((OH))) (from benzene to trimethylphosphane oxide and amines). The experimental results in CCl(4) are compared to those computed in the gas phase at various levels of theory. Ninety five percent of the variance of the red shift and 89% of the variance of the intensification of the OH stretching upon hydrogen bonding are explained by gas-phase B3LYP/6-31+G(d,p) calculations. However, this level does not satisfactorily explain the thermodynamic properties. Only 68% of the variance of the methanol affinity (-ΔH) is taken into account. MP2/aug-cc-pVTZ//B3LYP/6-31+G(d,p) affinity calculations raise the explanation to 77% for all HBAs and to 93% when three outliers (Me(2)SO, Me(3)PO, and tetrahydrothiophene) are excluded. Discrepancies are analyzed in terms of experimental errors, calculation approximations, and solvation.     

Intramolecular Cyclization of 1-Benzyl-2-(nitromethylene)pyrrolidines in Triflic Acid

1-Benzyl-2-(nitromethylene)pyrrolidines in triflic acid undergo intramolecular cyclization to afford the corresponding 2,3-dihydro-1H-pyrrolo[1,2-b]isoquinolinium triflates and/or 10-amino-2,3-dihydro-1H-pyrrolo[1,2-b]isoquinolinium triflates, depending on the nature of the aromatic substituent. Structures of products and reaction mechanisms are discussed.     

Solution of prey–predator problem by numeric–analytic technique

In this paper, an analytical expression for the solution of the prey–predator problem by an adaptation of the classical Adomian decomposition method (ADM). The ADM is treated as an algorithm for approximating the solution of the problem in a sequence of time intervals, i.e. the classical ADM is converted into a hybrid numeric–analytic method called the multistage ADM (MADM). Numerical comparisons with the classical ADM, and the classical fourth-order Rungge–Kutta (RK4) methods are presented.     

B3LYP and MP2 calculations of the enthalpies of hydrogen-bonded complexes of methanol with neutral bases and anions: comparison with experimental data

To perfect a method for building a theoretical hydrogen-bond basicity scale, the enthalpy of hydrogen bonding between methanol and thirteen neutral and anionic bases (MeOH, MeNH2, Me2NH, Et2NH, Me3N, Et3N, Br-, CN-, SH-, Cl-, HCOO-, MeO-, F-) was calculated by DFT and ab initio methods. The theoretical results were compared to selected experimental ones. It appears that B3LYP/6-31+G(d,p) calculations are satisfactory for optimizing the geometry of complexes and giving a general order of basicity. However, they are deficient for reproducing the large effect of alkyl groups on the hydrogen-bond basicity of amines. This deficiency is explained by intermolecular perturbation theory calculations, which show that the alkylation of nitrogen dramatically increases the dispersion energy component not taken into account by the B3LYP functional. Of the methods considered, only MP2/aug-cc-pVTZ calculations are capable of reproducing the binding enthalpy within the experimental error for the first-row acceptor atoms N, O, and F, and of accounting for dispersion effects created by alkylation at the hydrogen-bond acceptor site.