Volatile Profiling of Magnolia champaca Accessions by Gas Chromatography Mass Spectrometry Coupled with Chemometrics

Magnolia champaca (L.) Baill. ex Pierre of family Magnoliaceae, is a perennial tree with aromatic, ethnobotanical, and medicinal uses. The M. champaca leaf is reported to have a myriad of therapeutic activities, however, there are limited reports available on the chemical composition of the leaf essential oil of M. champaca. The present study explored the variation in the yield and chemical composition of leaf essential oil isolated from 52 accessions of M. champaca. Through hydrodistillation, essential oil yield was obtained, varied in the range of 0.06 ± 0.003% and 0.31 ± 0.015% (v/w) on a fresh weight basis. GC-MS analysis identified a total of 65 phytoconstituents accounting for 90.23 to 98.90% of the total oil. Sesquiterpene hydrocarbons (52.83 to 65.63%) constituted the major fraction followed by sesquiterpene alcohols (14.71 to 22.45%). The essential oils were found to be rich in β-elemene (6.64 to 38.80%), γ-muurolene (4.63 to 22.50%), and β-caryophyllene (1.10 to 20.74%). Chemometrics analyses such as PCA, PLS-DA, sPLS-DA, and cluster analyses such as hierarchical clustering, i.e., dendrogram and partitional clustering, i.e., K-means classified the essential oils of M. champaca populations into three different chemotypes: chemotype I (β-elemene), chemotype II (γ-muurolene) and chemotype III (β-caryophyllene). The chemical polymorphism analyzed in the studied populations would facilitate the selection of chemotypes with specific compounds. The chemotypes identified in the M. champaca populations could be developed as promising bio-resources for conservation and pharmaceutical application and further improvement of the taxa.     

Application of a Multilayer Perceptron Artificial Neural Network for the Prediction and Optimization of the Andrographolide Content in Andrographis paniculata

Andrographolide, the principal secondary metabolite of Andrographis paniculata, displays a wide spectrum of medicinal activities. The content of andrographolide varies significantly in the species collected from different geographical regions. Therefore, this study aims at investigating the role of different abiotic factors and selecting suitable sites for the cultivation of A. paniculata with high andrographolide content using a multilayer perceptron artificial neural network (MLP-ANN) approach. A total of 150 accessions of A. paniculata collected from different regions of Odisha and West Bengal in eastern India showed a variation in andrographolide content in the range of 0.28–5.45% on a dry weight basis. The MLP-ANN was trained using climatic factors and soil nutrients as the input layer and the andrographolide content as the output layer. The best topological ANN architecture, consisting of 14 input neurons, 12 hidden neurons, and 1 output neuron, could predict the andrographolide content with 90% accuracy. The developed ANN model showed good predictive performance with a correlation coefficient (R²) of 0.9716 and a root-mean-square error (RMSE) of 0.18. The global sensitivity analysis revealed nitrogen followed by phosphorus and potassium as the predominant input variables influencing the andrographolide content. The andrographolide content could be increased from 3.38% to 4.90% by optimizing these sensitive factors. The result showed that the ANN approach is reliable for the prediction of suitable sites for the optimum andrographolide yield in A. paniculata.     

Simultaneous determination of adenosine and inosine using single-wall carbon nanotubes modified pyrolytic graphite electrode

Voltammetric determination of adenosine and inosine has been carried out at single-wall carbon nanotubes (SWNTs) modified pyrolytic graphite electrode (PGE) at pH 7.2 using Osteryoung square wave voltammetry (OSWV). The modified electrode exhibits remarkable electrocatalytic properties towards adenosine and inosine oxidation with a peak potential of approximately 1229 mV and 1348 mV, respectively. Linear calibration curves are obtained over the concentration range 0.5 microM to 1.0 mM in adenosine and 10 microM to 1.0 mM in inosine with sensitivity of 1.0 microA microM(-1) and 1.9 microA microM(-1) for adenosine and inosine respectively. The limit of detection for adenosine and inosine was found to be 0.51x10(-7) M and 2.04x10(-7) M, respectively. The proposed method was also used to estimate these compounds in human blood plasma and urine samples and the method was validated using HPLC.     

Physicochemical properties and microstructure formation of the surfactant mixtures of sodium N-(2-(n-dodecylamino)ethanoyl)-L-alaninate and SDS in aqueous solutions

Aggregation behavior of a novel anionic amphiphilic molecule, sodium N-(2-(n-dodecylamino)ethanoyl)-L-alaninate (C(12)Ala), was studied in the presence of sodium dodecyl sulfate (SDS) surfactant at different [C(12)Ala]/[SDS] molar ratios and concentrations. The viscosity of aqueous SDS solution increased in the presence of C(12)Ala surfactant. The bulk viscosity of water was found to increase upon increase of both molar ratio and total surfactant concentration. The microenvironments of the self-assemblies were investigated using the fluorescence probe technique. Fluorescence anisotropy studies indicated formation of rodlike micelles. Both dynamic light scattering and small-angle neutron scattering measurements were performed to obtain the size and shape of the microstructures. The concentration and composition dependence of the hydrodynamic diameter of the aggregates were investigated. Transmission electron micrographs revealed the presence of a hexagonal liquid crystal phase in dilute solutions of the C(12)Ala-SDS mixture. The micrographs of moderately concentrated solution, however, showed cholesteric liquid-crystal structures with fingerprint-like texture. Temperature-dependent phase behavior of the self-assemblies was studied by use of the fluorescence probe technique.     

A tug-of-war between electronic excitation and confinement in a dynamical context

Quantum fluid density functional theory has been used to study the time evolution of various reactivity parameters such as hardness, electrophilicity, entropy, chemical potential, polarizability, electronegativity etc. in a confined environment during time dependent processes like atom-ion collision and atom-field interaction. Responses in the reactivity parameters of the helium atom, in the dynamical context, for ground state as well as in excited state, have been reported. The confinement is incorporated through a Dirichlet type boundary condition. With a decrease in the size of the cylindrical box, the system gets harder and less polarizable. Simultaneous excitation and confinement may bring back the ground state behavior.     

Role of Entropy-Corrected New Agegraphic Dark Energy in Hořava-Lifshitz Gravity

In this work, we have considered the entropy-corrected new agegraphic dark energy (ECNADE) model in Ho?ava-Lifshitz gravity in FRW universe. We have discussed the correspondence between ECNADE and other dark energy models such as DBI-essence, Yang-Mills dark energy, Chameleon field, Non-linear electrodynamics field and hessence dark energy in the context of Ho?ava-Lifshitz gravity and reconstructed the potentials and the dynamics of the scalar field theory which describe the ECNADE.     

Does Excited‐State Proton‐Transfer Reaction Contribute to the Emission Behaviour of 4‐Aminophthalimide in Aqueous Media?

4‐Aminophthalimide (AP) is an extensively used molecule both for fundamental studies and applications primarily due to its highly solvent‐sensitive fluorescence properties. The fluorescence spectrum of AP in aqueous media was recently shown to be dependent on the excitation wavelength. A time‐dependent blue shift of its emission spectrum is also reported. On the basis of these findings, the excited‐state solvent‐mediated proton‐transfer reaction of the molecule, which was proposed once but discarded at a later stage, is reintroduced. We report on the fluorescence behaviour of AP and its imide‐H protected derivative, N‐BuAP, to prove that a solvent‐assisted excited‐state keto–enol transformation does not contribute to the steady‐state and time‐resolved emission behaviour of AP in aqueous media. Our results also reveal that the fluorescence of AP in aqueous media arises from two distinct hydrogen‐bonded species. The deuterium isotope effect on the fluorescence quantum yield and lifetime of AP, which was thought to be a reflection of the excited‐state proton‐transfer reaction in the system, is explained by considering the difference in the influence of H₂O and D₂O on the nonradiative rates and ground‐state exchange of the proton with the solvent.     

Microwave-induced bismuth(III)-catalyzed synthesis of linear indoloquinolines

Microwave-induced Bi(NO₃)₃-catalyzed one-pot synthesis of a series of linear indoloquinolines is accomplished under mild reaction conditions. While majority of these examples were carried out under solvent-free conditions, in a few cases, minimal quantity of THF is used as solvent. The methodology involves several unique reaction pathways, providing different linear indolo[2,3-b]quinolines in good yields from readily available starting materials and using environmentally benign Bi(NO₃)₃·5H₂O as catalyst.     

Dual Reactivity of 1,2,3,4‐Tetrazole: Manganese‐Catalyzed Click Reaction and Denitrogenative Annulation

A general catalytic method using a Mn‐porphyrin‐based catalytic system is reported that enables two different reactions (click reaction and denitrogenative annulation) and affords two different classes of nitrogen heterocycles, 1,5‐disubstituted 1,2,3‐triazoles (with a pyridyl motif) and 1,2,4‐triazolo‐pyridines. Mechanistic investigations suggest that although the click reaction likely proceeds through an ionic mechanism, which is different from the traditional click reaction, the denitrogenative annulation reaction likely proceeds via an electrophilic metallonitrene intermediate rather than a metalloradical intermediate. Collectively, this method is highly efficient and offers several advantages over other methods. For example, this method excludes a multi‐step synthesis of the N‐heterocyclic molecules described and produces only environmentally benign N₂ gas a by‐product.     

A reusable polymer anchored copper(II) complex catalyst for the efficient oxidation of olefins and aromatic alcohol

A new heterogeneous Schiff base copper(II) complex was prepared by reacting amino‐polystyrene with salicylaldehyde followed by complexation with cupric chloride. The structure of this immobilized complex has been established on the basis of scanning electron microscope (SEM), thermogravimetric analysis (TGA), elemental analysis employing atomic absorption spectroscopy (AAS), and spectrometric methods like diffuse reflectance spectra of solid (DRS) and fourier transform infrared spectroscopy (FTIR). Catalytic activity of this polymer anchored Cu(II) complex was tested by studying the oxidation of cyclohexene, styrene, and benzyl alcohol in the presence of tert‐ butylhydroperoxide as oxidant. Several parameters such as solvent, oxidant, reaction time, reaction temperature, amount of catalyst, and substrates oxidant ratio were varied to optimize the reaction condition. Under optimized reaction conditions, cyclohexene gave a maximum of 74% conversion with three major products 2‐cyclohexene‐1‐one, cyclohexene epoxide, and 2‐cyclohexene‐1‐ol. The conversions of styrene and benzylalcohol proceed with 53% and 77%, respectively. Styrene gives styrene epoxide as the major product while benzylalcohol gives benzaldehyde as the major product. The catalytic results reveal that polymer anchored copper(II) Schiff base complex can be recycled more than five times without much loss in the catalytic activity. Copyright © 2009 John Wiley & Sons, Ltd.