Selective polarity- and adsorption-guided extraction/purification ofAnnona sp. Polar acetogenins and biological assay against agricultural pests

Annonaceae acetogenins (AG) comprise a family of natural chemical modifications of long-chain fatty acids (C₃₅_₃₇) bearing one to several hydroxyls (less often oxo), middle-chain tetrahydrofuran rings, and a γ-lactonized, α/β-unsaturated carboxyl group. Acetogenins’ strong biological activity as larvicides, pesticides, and antitumorals is dependent on these structural variations. The hydroxylation degree is particularly important for these etfects. Seeds, albeit rich in fats (mostly triacylglycerols, [TAG]), are a nonpredatory source of these drugs as compared to other botanical parts such as roots and stems. Conventional lipid extractions lead to quantitative lipid recovery and then the unfavorable natural ratio of TAG:AG in the range >90:<0.1 These extracts thus require, for instance, partitions and extensive sílica gel column chromatographic steps, in order to enrich or purify the AG fraction(s). Great operational difficulties result from the similar polarity and mol. wt. range of TAG and AG when carrying out these purification steps. An alternative fast two-step procedure to obtain polar acetogenin (pAG)-enriched preparations was developed. The extraction procedure forAnnona spp. seeds pAG was carried out with acetonitrile (Eβ = 0.65; log P = - 0.33) as a polar organo-solvent, followed by the adsorption of the solvent-free extract on activated charcoal, then washed with hexane and/or chloroform (Eβ = 0.0 and 0.40: log P = 3.5 and 2.0) for most of the contaminating TAG removal, and then with acetone (Eβ = 0.56; log P = - 0.23) to the desorption of an enrichedpAG fraction. An alternative procedure for pAG extraction was supercritical fluid extraction (SFE) at moderate thermopressurization conditions (65-82βC; 120-130 atm) using CO2, with 10% acetonitrile as the polarity modifier. The pAG fractions’ bioactivity was evaluated with the brine-shrimp test (BST), and for feed deterrance, growth inhibition, and lethality against the high-impact agricultural pestsAnticarsia gemmatalis andPseudaletia sequax caterpillars feeding on soya or grass leaves sprayed with a 10% alcohol-stabilized emulsion of pAG.     

Distribution and speciation of selenium in Lecythis ollaria plant

Selenium has been determined in different parts of the Lecythis ollaria (LO) plant (Venezuela) and the determination of its speciation has been achieved in fruit seeds. The study has been performed using different analytical techniques including inductively coupled plasma atomic emission spectrometry (ICP-AES), differential pulse cathodic stripping voltammetry (DPCSV), instrumental neutron activation analysis (INAA), high performance liquid chromatography (HPLC) and mass spectrometry (MS). Different parts of the plant (leaves, bark, capsules and seeds) were examined as well as the soil where LO was growing. Among different considered parts, seeds show the highest content in selenium (5 g kg⁻¹) which is dependent on the maturation extent of the fruit. In seeds, about half of the total selenium content is soluble in water while the remaining is involved in protein structure. In the aqueous fraction, the prevailing form of selenium appears to be seleno-cystathionine with much lower amounts of Se(VI) and Se(IV).     

EPR and IR spectral investigations on some leafy vegetables of Indian origin

EPR spectral investigations have been carried out on four edible leafy vegetables of India, which are used as dietary component in day to day life. In Rumex vesicarius leaf sample, EPR spectral investigations at different temperatures indicate the presence of anti-ferromagnetically coupled Mn(IV)–Mn(IV) complexes. EPR spectra of Trigonella foenum graecum show the presence of Mn ions in multivalent state and Fe³⁺ ions in rhombic symmetry. EPR spectra of Basella rubra indicate the presence of Mn(IV)–O–Mn(IV) type complexes. The EPR spectra of Basella rubra have been studied at different temperatures. It is found that the spin population for the resonance signal at g = 2.06 obeys the Boltzmann distribution law. The EPR spectra of Moringa oliefera leaves show the presence of Mn²⁺ ions. Radiation induced changes in free radical of this sample have also been studied. The FT-IR spectra of Basella rubra and Moringa oliefera leaves show the evidences for the protein matrix bands and those corresponding to carboxylic CO bonds.     

X-ray Crystal and Ab Initio Structures of 3′,5′-di-O-Acetyl-N(4)-Hydroxy-2′-Deoxycytidine and Its 5-Fluoro Analogue: Models of the N(4)-OH-dCMP and N(4)-OH-FdCMP Molecules Interacting with Thymidylate Synthase

The crystal and molecular structures of the 3′,5′-di-O-acetyl-N(4)-hydroxy-2′-deoxycytidine molecule and its 5-fluoro congener have been determined by X-ray single crystal diffraction. The 3′,5′-di-O-acetyl-N(4)-hydroxy-5-fluoro-2′-deoxycytidine molecule crystallizes in the space group C2 with the following unit cell parameters: a = 21.72 Å, b = 8.72 Å, c = 8.61 Å, and β = 90.42^∘. 3′,5′-di-O-acetyl-N(4)-hydroxy-2′-deoxycytidine also belongs to the monoclinic space group C2 and the unit cell parameters are: a = 39.54 Å, b = 8.72 Å, c = 22.89 Å, and β = 95.26^∘. The non-fluorine analogue demonstrates a rare example of crystal structure with five symmetry-independent molecules in the unit cell. All the molecules in both crystal structures have the sugar residue anti oriented with respect to the base, as well as have the N(4)-OH residue in cis conformation relatively to the N(3)-nitrogen atom. In addition to the molecular geometries from X-ray experiment, the optimized molecular geometries have been obtained with the use of theoretical ab initio calculations at the RHF/6-31G(d) level. The corresponding geometric parameters in the molecules of 3′,5′-di-O-acetyl-N(4)-hydroxy-2′-deoxycytidine and its 5-fluoro congener have been compared. The differences including the C(5)=C(6) bond shortening and C(4)—C(5)—C(6) angle widening in the fluorine analogue are discussed in this paper in relation to the molecular mechanism of enzyme, thymidylate synthase, inhibition by N(4)-hydroxy-2′-deoxycytidine monophosphate and its 5-fluoro congener.     

Voltammetric Behavior of Strychnine, and its Determination in Strychno Nux-Vomica Seeds Extract

The voltammetric behavior of strychnine has been studied with a pyrolytic graphite (PG) electrode. The redox process taking place at the PG electrode is discussed. The cyclic voltammetric response has also been evaluated with respect to various experimental conditions, such as scan rate, pH of the supporting electrolyte, strychnine concentrations and accumulation time. A highly sensitive voltammetric method for the determination of strychnine is consequently developed. The linear calibration is in the range of 1×10⁻⁶ M – 1.1×10⁻⁴ M, with the limit of detection (LOD) being 1×10⁻⁸ M. The precision is excellent with a relative standard deviation (RSD) of 2.3%. The proposed cyclic voltammetric methodology has been applied to the determination of strychnine in the extract of Strychno nux-vomica seeds using the standard addition method. Consistent results have been obtained from both the electrochemical approach described here and the previously reported HPLC method.     

On the interaction of metal extractant reagents. Investigation of the aggregation ofdi(2,4,4-trimethylpentyl)phosphinic acid anddi(n-octyl)phosphinic acid in toluene by vapour-pressure osmometry

Summary The aggregation equilibria ofdi(2,4,4-trimethylpentyl)phosphinic acid (HDTMPP) anddi(n-octyl)phosphinic acid (HDOP) dissolved in toluene have been investigated by vapour-pressure osmometry (VPO) at different temperatures. The experimental data have been treated both graphically and numerically, and the average aggregation numberñ as well as the aggregation constant have been determined. The results suggest that dimers are formed and that the dimerization constant decreases with temperature. Finally, the enthalpies for the aggregation ofdi(2,4,4-trimethylpentyl)phosphinic acid anddi(n-octyl)phosphinic acid in toluene have been estimated using thevan't Hoff equation.

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Über die Wechselwirkung metallextrahierender Reagentien. Untersuchung der Aggregation vondi-(2,2,4-Trimethylpentyl)-phosphinsäure unddi-(n-Octyl)-phosphinsäure in Toluol mittels Dampfdruckosmometrie

Zusammenfassung Die Aggregationsgleichgewichte von in Toluol gelösterdi-(2,4,4-Trimethylphentyl)-phosphinsäure (HDTMPP) unddi-(n-Octyl)-phosphinsäure (HDOP) wurden mittels Dampfdruckosmometrie (VPO) bei verschiedenen Temperaturen untersucht. Die experimentellen Daten wurden sowohl graphisch als auch numerisch ausgewertet; es wurden sowohl die mittlere Aggregationszahlñ als auch die Aggregationskonstante bestimmt. Die Resultate lassen vermuten, daß Dimere gebildet werden und die Dimerisationskonstante mit der Temperatur abnimmt. Mit Hilfe dervan't Hoffschen Gleichung wurden die Enthalpien der Aggregation vondi-(2,4,4-Trimethylpentyl)-phosphinsäure unddi-(n-Octyl)-phosphinsäure in Toluol abgeschätzt.

     

Indirect spectrophotometric determination of diltiazem hydrochloride in pure form and pharmaceutical formulations

Three simple, accurate, and sensitive spectrophotometric methods (A, B and C) have been described for the indirect assay of diltiazem hydrochloride (DIL.HCl), either in pure form or in pharmaceutical formulations. The first method (A) is based on the oxidation of DIL.HCl by N-bromosuccinimide (NBS) and determination of unconsumed NBS by measuring the decrease in absorbance of amaranth dye (AM) at a suitable λ _max =521 nm. Other methods (B) and (C) involve the addition of excess cerric ammonium sulfate (CAS) and subsequent determination of the unconsumed oxidant by a decrease in the red color of chromotrope 2R (C2R) at a suitable λ _max =528 nm or a decrease in the orange-pink color of rhodamine 6G (Rh6G) at λ _max =525 nm, respectively. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges 3.0–9.0, 3.5–7.0 and 3.5–6.3 μg ml⁻¹ for methods A, B and C, respectively. The apparent molar absorptivity, Sandell's sensitivity, detection and quantification limits were calculated. The proposed methods have been applied successfully for the analysis of the drug in its pure form and its dosage form. No interference was observed from a common pharmaceutical adjuvant. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.     

Molar Excess Volumes and Excess Isentropic Compressibilities of Ternary Mixtures Containing <Emphasis Type="Italic">o</Emphasis>-Toluidine

Molar excess volumes, V _ijk ^E, and speeds of sound, U _ijk , of o-toluidine (i) + benzene (j) + cyclohexane or n-hexane or n-heptane (k) ternary mixtures have been measured as a function of composition at 308.15 K. The observed speed of sound data have been utilized to determine the excess isentropic compressibilities, (K _S ^E) _ijk , of the ternary (i+j+k) mixtures. The Moelywn-Huggins concept (Huggins in Polymer 12: 389–399, 1971) of connectivity between the surfaces of the binary mixture constituents has been extended to ternary mixtures (using the concept of a connectivity parameter of third degree of molecules, ³ ξ, which in turn depends on its topology) to obtain an expression that describes well the measured V _ijk ^E and (K _S ^E) _ijk data. The observed data have also been analyzed in terms of Flory’s theory.     

Mechanistic investigations of oxidation of isatins by sodium N-chlorobenzenesulfonamide in alkaline medium: A kinetic study

Oxidation of isatins (isatin, 5-methylisatin, 5-bromoisatin and 5-nitroisatin) to their anthranilic acids was performed efficiently with sodium N-chlorobenzenesulfonamide or chloramine-B (CAB) in alkaline medium at 35±0.1°C. The reactions follow identical kinetics for all the isatins, being first-order dependence each in [CAB] _o and [Isatin] _o and inverse fractional-order on [NaOH]. Addition of halide ions and benzenesulfonamide, reduction product of CAB, do not significantly affect the rate. Variation of ionic strength of the medium had no effect on the rate, while the dielectric effect is negative. The solvent isotope effect was studied using D₂O. Activation parameters for the overall reaction have been computed. The rates satisfactorily correlate with the Hammett σ relationship and the reaction constant ρ is −0.31 signifies that electron releasing groups accelerate the reaction while the electron withdrawing groups retard the rate. Values of ΔH^≠ and ΔS^≠ are linearly related and an isokinetic relationship is observed with β=376 K, indicating the reaction is controlled by enthalpy. The stoichiometry of the title reaction is found to be 1∶1. Oxidation products of isatins were identified as their corresponding anthranilic acids and the yields were found to be around 90 %. The observed results have been explained by a plausible mechanism and the related rate law deduced. This method offers several advantages including high yield of the products, short reaction times, easier isolation of products, and stable, cost effective and relatively non-toxic reagents, which make the reaction process simple and smooth.     

Synthesis and properties of new chelating resin with a spacer containing alpha-nitroso-beta-naphthol as the functional group

A new chelating ion-exchange resin with a spacer CH₂-NH-C₆H₄- based on a microreticular chloromethylated styrene-divinylbenzene copolymer containing α-nitroso-β-naphthol as a functional group has been synthesized. The sorption characteristics for manganese(II), iron(III), cobalt(II), nickel(II), copper(II), and zinc(II) have been investigated over the pH range 1.0–7.0. The resin is highly stable in acidic and alkaline medium. Iron(III) and cobalt(II); copper(II) and iron(III) are separated very effectively in a column operation by stepwise elution.     

Properties of the seed gum of stryphnodendron barbatiman (Barbatimäo)

Pretreatment resulting in enzymatic inactivation proved to be essential for the preparation of highly viscous solutions of the galactomannan from seeds ofS. barbatiman ([η]= 1400 mL/g). Short periods of reflux with aqueous methanol or ethanol or treatment with boiling water of the seeds was used. The target for the inactivation step is a β-d-endo-mannanase activity present in the dormant seeds.     

Fungicidal lipid-transfer peptide from <Emphasis Type="Italic">Daucus carota sativa</Emphasis> seeds

A non-specific lipid-transfer peptide (nsLTP) with fungicidal activity was isolated from Daucus carota sativa carrot seeds. Peptides were purified by a method including aqueous extraction, anion-exchange chromatography over CM-TSK-650M, and HPLC over a column of 250/8/4 Protein@Peptide C₁₈ using an acetonitrile gradient. The molecular weight of the peptide was determined as 9624 Da by mass spectrometry. The peptide was found to have fungicidal activity against the pathogenic fungus Verticillium dahliae. The partial N-terminal sequence, which was highly homologous to the N-terminal sequences of lipid-transfer peptides from seeds of rice, tobacco, and maize, was determined using Edman automated sequencing. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 371–373, July–August, 2007.     

Ionization of aqueous toluic acids: Conductance and thermodynamics

Conductivities of aqueous solutions ofortho-, meta-, andpara-toluic acids have been measured for the concentration range 0.1–2 millimolar and at 5° intervals from 5 to 100°C. At each temperature pK _a(m) andA ₀ have been calculated using the paired ion model recently described by Fuoss. Thermodynamic parameters have been calculated for the ionization of each acid, and Walden products for the anions. Results are discussed in terms of contributions to acidity by enthalpy and entropy changes as well as by hydration of the various solute species.     

Polysaccharides of Fabaceae. II. Galactomannan from <Emphasis Type="Italic">Astragalus danicus</Emphasis> seeds

Galactomannan of molecular weight 472 kDa was isolated from Astragalus danicus Retz. (Fabaceae) seeds and consisted of galactose and mannose units in a 1:1.40 molar ratio. The main chain of the macromolecule was constructed of 1,4-β-D-mannopyranose units, 71% of which were substituted at C-6 by single α-D-galactopyranose units. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 255257, May-June, 2009.     

Complexes of rare-earth metals with meconic acid

Two series of complexes of meconic acid (H₃ Mec) with rare-earths have been prepared by varying the preparative procedure. The compounds have the general formulae, [Ln(Mec) (H₂O)₂]·3 H₂O (whereLn=La, Ce, Pr, Nd, Sm, Ho and Y) and [Ln(HMec) (H₂ Mec) (H₂O)₂]·4 H₂O (whereLn=La, Pr, Nd and Sm). The infrared spectral data indicate that the carboxylate groups are bound to the rare-earth metal in a bidentate fashion. Thermal studies indicate that two water molecules are coordinated in each case. The complexes are probably polymeric.

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Komplexe von Seltenerd-Metallen mit Meconsäure

Zusammenfassung Es wurden zwei Reihen von Komplexen der Meconsäure (H₃ Mec) mit Seltenerd-Metallen mit den allgemeinen Formeln [Ln(Mec)(H₂O)₂]·3 H₂O (Ln=La, Ce, Pr, Nd, Sm, Ho, Y) und [Ln(HMec)₂(H₂ Mec) (H₂O)₂]·4 H₂O (Ln=La, Pr, Nd, Sm) hergestellt. Die IR-Spektren zeigen, daß die Carboxylat-Gruppen in zweizähniger Weise mit den Metallionen koordinieren; thermische Untersuchungen ergeben, daß in beiden Reihen jeweils zwei Wassermoleküle zusätzlich koordiniert sind. Die Komplexe weisen wahrscheinlich eine Polymerstruktur auf.

     

207Pb-NMR-Untersuchungen an Bleiorganylen

The high-resolution²⁰⁷Pb magnetic resonance spectra ofR _4–n PbX _n (R=Methyl, Ethyl;X=h₁-Cyclopentadienyl, Chloride;n=1, 2) have been studied at 16.72Mc. The²⁰⁷Pb- ·· -¹H spin-spin coupling constants for the molecules described have been obtained by analysis of the first order NMR-patterns as A_xB_yM and A_xB_yC_zM respectively. The experimental spectra have been verified by a computer simulation. The chemical shifts and coupling constants of the lead organyls investigated show similar dependences on moleculare structure as well as number and species of the substituents like analogous organotin compounds.

     

Zirconium(IV) complexes ofSchiff bases

Zirconium(IV)Schiff base derivatives have been synthesised by reacting zirconium isopropoxide with monofunctional bidentateSchiff bases in different stoichiometric ratios. The resulting derivatives of the type Zr(O-Isopr)₃(SB) and Zr(O-Isopr)₂(SB)₂, whereSB ^– is the anion of the correspondingSchiff baseSBH, have been isolated in almost quantitative yields. Their molecular weights have been determined ebullioscopically and their ir spectra recorded.

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Zirkonium(IV)-Komplexe von Schiff-Basen

Zusammenfassung Es wurden Zirkonium(IV)-Schiff-Basen-Derivate in verschiedenen stöchiometrischen Zusammensetzungen über die Reaktion von Zirkoniumisopropoxid mit monofunktionellen zweizähnigenSchiff-Basen synthetisiert. Die Komplexe vom Typ Zr(O-Isopr)₃(SB) und Zr(O-Isopr)₂(SB)₂ [SB ^– als Anion derSchiff-BaseSBH] wurden in fast quantitativer Ausbeute erhalten. Es werden Strukturen vorgeschlagen, die auf ebullioskopisch bestimmten Molekulargewichten und den IR-Spektren basieren.

     

Evolution of Brassica rapa var. rapa L. volatile composition by HS-SPME and GC/IT-MS

Brassica rapa var. rapa L. (turnip) is highly appreciated and consumed by human. In this work, the volatile profile of B. rapa var. rapa was studied during the maturation process. The volatiles of seeds, sprouts with 6 and 9 days, and adult plant were determined using headspace solid-phase microextraction (HS-SPME) combined with gas chromatography/ion trap-mass spectrometry (GC/IT-MS).Several constituents, including alcohols, aldehydes, esters, ketones, norisoprenoids, nitrogen and sulphur compounds were characterized, totalizing 64 compounds. Isothiocyanates are the main volatiles in all matrices, being 3-butenyl isothiocyanate the major compound. Qualitative and quantitative differences were found among the analysed materials. Nitrogen and sulphur compounds decreased during the maturation process, while terpenes, aldehydes, norisoprenoids and ester compounds were present in higher amounts during germination, especially in sprouts with 9 days of development.