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1.

Background

Obtaining new pharmaceutical materials with enhanced properties by using natural compounds and environment-friendly methods is a continuous goal for scientists. Ficaria verna Huds. is a widespread perennial plant with applications in the treat of haemorrhoids and to cure piles; it has also anti-inflammatory, astringent, and antibiotic properties. The goal of the present study is the obtaining and characterization of new F. verna extract/??-cyclodextrin complexes by using only natural compounds, solvents, and environment-friendly methods in order to increase the quality and acceptability versus toxicity indicator. Thus, the flavonoid content (as quercetin) of Ficaria verna Huds. flowers and leaves from the West side of Romania was determined and correlated with their antioxidant activity. Further, the possibility of obtaining ??-cyclodextrin supramolecular systems was studied.

Results

F. verna flowers and leaves extracts were obtained by semi-continuous solid-liquid extraction. The raw concentrated extract was spectrophotometrically analyzed in order to quantify the flavonoids from plant parts and to evaluate the antioxidant activity of these extracts. The F. verna extracts were used for obtaining ??-cyclodextrin complexes; these were analyzed by scanning electron microscopy and Karl Fischer water titration; spectrophotometry was used in order to quantifying the flavonoids and evaluates the antioxidant activity. A higher concentration of flavonoids of 0.5% was determined in complexes obtained by crystallisation method, while only a half of this value was calculated for kneading method. The antioxidant activity of these complexes was correlated with the flavonoid content and this parameter reveals possible controlled release properties.

Conclusions

The flavonoid content of F. verna Huds. from the West side of Romania (Banat county) is approximately the same in flowers and leaves, being situated at a medium value among other studies. ??-Cyclodextrin complexes of F. verna extracts are obtained with lower yields by crystallisation than kneading methods, but the flavonoids (as quercetin) are better encapsulated in the first case most probably due to the possibility to attain the host-guest equilibrium in the slower crystallisation process. F. verna extracts and their ??-cyclodextrin complexes have antioxidant activity even at very low concentrations and could be used in proper and valuable pharmaceutical formulations with enhanced bioactivity.  相似文献   

2.
Droserae herba is a drug commonly used for treatment of convulsive or whooping cough since the seventeenth century. Because of the contribution of flavonoids and ellagic acid derivatives to the therapeutic activity of Droserae herba, an LC?CDAD method has been developed for quantification of these analytes in four Drosera species used in medicine (Drosera anglica, D. intermedia, D. madagascariensis, and D. rotundifolia). During elaboration of the method 13 compounds, including three substances not previously described for Drosera species, were detected and unambiguously identified by means of extensive LC?CMS and LC?CNMR experiments and by off-line heteronuclear 2D NMR after targeted isolation. The most prominent component of D. rotundifolia and D. anglica, 2??-O-galloylhyperoside, with myricetin-3-O-??-glucopyranoside and kaempferol-3-O-(2??-O-galloyl)-??-galactopyranoside, were identified for the very first time in this genus. The LC?CDAD method for quantification was thoroughly validated, and enables, for the first time, separation and precise analysis of these analytes in Droserae herba. Simple sample preparation and use of a narrow-bore column guarantee low cost and simplicity of the suggested system, which is excellently suited to quality control of the drug or herbal medicinal products containing this drug.
Figure
2??-O-galloylhyperoside - a major compound in Drosera anglica and Drosera rotundifolia  相似文献   

3.
The following compounds have been synthesized: (a) hydantoins 5,5-dimethylimidazolidine-2,4-dione (1), 1??,3??-dihydrospiro[imidazolidine-4,2??-indene]-2,5-dione (2), 3??,4??-dihydro-1??H-spiro[imidazolidine-4,2??-naphthalene]-2,5-dione (3); (b) monomers: 5,5-dimethyl-3-(4-vinylbenzyl)imidazolidine-2,4-dione (4), 1-(4-vinylbenzyl)-1??,3??-dihydrospiro[imidazolidine-4,2??-indene]-2,5-dione (5), 1-(4-vinylbenzyl)-3??,4??-dihydro-1??H-spiro[imidazolidine-4,2??-naphthalene]-2,5-dione (6), (two of them are unknown: 5 and 6); (c) macromolecular compounds: poly(chloromethyl-p-styrene) (7), used as reference, and three polymers (two of them are novel) obtained by substitution of hydantoins 1?C3 to poly(methyl-p-styrene) (8?C10). Their thermal properties have been studied by thermogravimetry. It was found that the chemical structure, tautomerization, and intermolecular interaction influence the thermal stability of substrates. The presence of phenyl rings causes the increase of resistance of studied hydantoins. The obtained polymers are characterized by significantly improved thermal stability comparing to poly (chloromethyl-p-styrene). The mechanism of thermal degradation of investigated polymers and explanation of their thermal resistance has been proposed. The relatively high temperatures of glass transition of polymers have been determined by DSC.  相似文献   

4.
In polyhedral crystallography, non-Euclidean possibilities come into considerations as well. The so-called football manifolds appearing in the Bolyai?CLobachevskian hyperbolic space (H 3) can model ??fullerens?? very probably. This may give us the feeling that??in atomic measure??space can wear non-Euclidean structures, e.g., hyperbolic (H 3), spherical (S 3) and other ones, respectively. Such phenomena as pentagonal or decagonal symmetry and the discovery of quasicrystals might strengthen these impressions. We examine here some Archimedean solids: (4, 6, 6) in E 3 (the truncated octahedron in the classical Euclidean space, for analogue as motivation, Fig.?1); (5, 6, 6) the ??real football?? (now in H 3, Fig.?2, from Molnár in Proceedings of International Conference on Differential Geometry and Its Applications, 1988), (3, 10, 10) in H 3 (Fig.?3 from Molnár in the previous Proceedings); an extra solid (4, 6, 8) with two manifolds on it in H 3 (Figs.?4, 5), published first time in this paper. Furthermore (3, 8, 8) will be realized in the spherical space S 3 (Fig.?6). We can study this classical example as a simple non-Euclidean one also for motivation to our method (see also Molnár in Acta Cryst A61:542?C552, 2005, as an introductory paper). Each of them will be a manifold, i.e., it can be endowed with an appropriate face pairing (topological glueing), so that every point has a ball-like neighborhood in the corresponding space, especially of constant curvature, but completely in the classical analogy. In addition, each manifold will be compact (bounded and closed) whose fundamental group can be generated by two screw motions.  相似文献   

5.
A high-performance liquid chromatographic method has been developed for the simultaneous analysis of the flavonols myricitrin (1), avicularin (2), and juglanin (3) in rat plasma and urine after oral administration of the total flavonoids from Polygonum aviculare. Samples were prepared by solid-phase extraction then separated on a C18 reversed-phase column by use of a mobile-phase gradient prepared from methanol and aqueous formic acid solution. The flow rate was 1 mL min?1. Detection was performed at 254 nm. The calibration range was 11–1,100 μg mL?1 for both 2 and 3 in plasma; in urine the calibration ranges for 1, 2, and 3 were 32–1,600, 11–1,100, and 22–1,100 μg mL?1, respectively. Intra-day and inter-day RSD were less than 4.33 and 3.62% for 2 and 3, respectively, in plasma, and no more than 4.03 and 2.22% for all the analytes in urine. The analytical sensitivity and selectivity of the assay enabled successful application to pharmacokinetic studies of flavonols 13 in rats.  相似文献   

6.

Background

Epitope tags and fluorescent fusion proteins have become indispensable molecular tools for studies in the fields of biochemistry and cell biology. The knowledge collected on the subdomain organization of the two subunits of the adhesion complex dystroglycan (DG) enabled us to insert the 10 amino acids myc-tag at different locations along the ??-subunit, in order to better visualize and investigate the DG complex in eukaryotic cells.

Results

We have generated two forms of DG polypeptides via the insertion of the myc-tag 1) within a flexible loop (between a.a. 170 and 171) that separates two autonomous subdomains, and 2) within the C-terminal domain in position 500. Their analysis showed that double-tagging (the ??-subunit is linked to GFP) does not significantly interfere with the correct processing of the DG precursor (pre-DG) and confirmed that the ??-DG N-terminal domain is processed in the cell before ??-DG reaches its plasma membrane localization. In addition, myc insertion in position 500, right before the second Ig-like domain of ??-DG, proved to be an efficient tool for the detection and pulling-down of glycosylated ??-DG molecules targeted at the membrane.

Conclusions

Further characterization of these and other myc-permissive site(s) will represent a valid support for the study of the maturation process of pre-DG and could result in the creation of a new class of intrinsic doubly-fluorescent DG molecules that would allow the monitoring of the two DG subunits, or of pre-DG, in cells without the need of antibodies.  相似文献   

7.
Reactions of bis(acetylacetonato)oxovanadium(IV) with N??-[1-(2-hydroxynaphthyl)ethylidene]-4-nitrobenzohydrazide (H2HNB) and 2-hydroxy-N??-[1-(2-hydroxynaphthyl)ethylidene]benzohydrazide (H2HHB), respectively, product two oxovanadium(V) species with the formulas [VO(OMe)(HNB)]2 (I) and [VO(OMe)(HHB)] (II). The complexes I and II have been characterized by elemental analysis, IR spectra, and single crystal X-ray diffraction. The crystal of I is monoclinic: space group P21/n, a = 8.208(2), b = 14.528(3), c = 16.418(3) ?, ?? = 97.887(3)°, V = 1939.3(7) ?3, Z = 2. The crystal of II is triclinic: space group P $P\bar 1$ a = 8.334(2), b = 10.236(2), c = 11.337(2) ?, ?? = 80.91(3)°, ?? = 75.41(3)°, ?? = 75.63(3)°, V = 902.0(3) ?3, Z = 2. Complex I is a methoxide-bridged dimeric oxovanadium(V) complex, and complex II is a mononuclear oxovanadium(V) complex. The V atom in I is in an octahedral coordination, and that in II is in a square pyramidal coordination.  相似文献   

8.
A reaction of ammonium tetra(isothiocyanato)diamminechromate(III) (ammonium reineckate) with ?-caprolactam in aqueous solution at different pH values gave the novel complexes (NH4)[Cr(NH3)2(NCS)4] · 7Cpl (I), (NH4)[Cr(NH3)2(NCS)4] · 2.5Cpl · 0.5(H2O) (II), and (HCpl2)[Cr(NH3)2(NCS)4] (III), where Cpl is ?-caprolactam (?-C6H11NO). The crystals of complexes I?CIII are triclinic, space group $P\bar 1$ ; I: a = 12.7058(4) ?, b = 13.2544(4) ?, c = 19.4487(7) ?, ?? = 105.2360(10)°, ?? = 106.6410(10)°, ?? = 91.5290(10)°, V = 3009.37(17) ?3, ??calc = 1.245 g/cm3, Z = 2; II: a = 12.3144(5) ?, b = 12.6518(5) ?, c = 23.3300(8) ?, ?? = 75.4580(10)°, ?? = 80.0760(10)°, ?? = 61.0830(10)°, V = 3074.1(2) ?3, ??calc = 1.358 g/cm3, Z = 4; III: a = 6.4701(4) ?, b = 12.5973(9) ?, c = 16.5556(12) ?, ?? = 108.769(2)°, ?? = 98.543(2)°, ?? = 90.345(2)°, V = 1261.36(15) ?3, ??calc = 1.437 g/cm3, Z = 2. The structure refinement for (HCpl2)3[Cr(NCS)6] (IV) was revised. Like complex III, complex IV contains the cation (HCpl2)+ stabilized by a strong hydrogen bond between the O atoms of the ?-caprolactam molecules; the cation was structurally characterized for the first time.  相似文献   

9.
A hydrated crystalline ionized adduct of dibenzo-18-crown-6 and perchloric acid DB18C6 · H3O+ · CiO 4 ? · 3H2O (I) is synthesized and characterized by X-ray diffraction. The crystals of I are monoclinic: a = 17.760 Å, b = 12.922 Å, β = 124.27°, Z = 4, space group Cc. The structure of I is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.079 for 3294 independent reflections (CAD4 automated diffractometer, λMoK α radiation). A DB18C6 molecule has a butterfly conformation with the rough symmetry C 2v . An H3O+ · H2O dimer is situated on one side of the DB18C6 macrocycle, and the ClO 4 ? anion and two other water molecules are on the other side. In the crystal of I, the DB18C6 molecules, H3O+ and ClO 4 ? ions, and water molecules are linked through intermolecular (interionic) hydrogen bonds to form broad infinite chains running along the z axis.  相似文献   

10.
Ab initio molecular orbital and density functional theory calculations with inclusion of dispersion interaction effect are employed to reveal the characteristic features of intermolecular interactions for the molecular capsule (1 6) consisting of six gear-shaped amphiphile molecules (1) discovered by Hiraoka et al. (J Am Chem Soc 130:14368?C14369, 2008). The contributions of CH?C?? and ?ШC?? type dispersion energies are found to be indispensable for the formation of hexameric capsule 1 6 by the analysis of decomposed interaction energies between fragmented-model species in the 1 molecule. We have also calculated the hexameric capsule (2 6) from demethylated 1 molecule (2). Such subtle structural difference induces the different characters of intermolecular interactions, in which the stabilization energy of hexameric 2 6 capsule is about 40?kcal/mol smaller than that of the original 1 6 capsule, due to the lack of three methyl groups for the CH?C?? interactions in 2 molecules.  相似文献   

11.
Xiaomei He  Rui Lin  Hua He  Meiling Sun  Deli Xiao 《Chromatographia》2012,75(23-24):1355-1363

Purpose

In this study, direct separation of ketoprofen enantiomers was performed on a Chirobiotic T column.

Methods

The effects of the type and amount of the organic modifier, buffer concentration, pH value, temperature and flow rate on retention and selectivity were investigated. Experiments were carried out in the temperature range of 20?C40?°C to study the effects of temperature. Thermodynamic parameters were calculated from plots of ln k or ln ?? versus 1/T. Molecular dynamics simulation was done to investigate interactions between ketoprofen enantiomers and the chiral selector??teicoplanin.

Results

It was observed that pH and flow rate had a large influence on resolution. Baseline separation of ketoprofen enantiomers could be achieved with low amounts of methanol, high temperature and high buffer concentrations.

Conclusions

Results from a thermodynamic study and molecular dynamics simulation show that steric hindrance effect, ?ШC?? complexation, hydrogen bonding and electrostatic forces are the main driving forces which cause chiral recognition of ketoprofen enantiomers.  相似文献   

12.
Three anion receptors based on urea: 1 N, N??-bis-(p-nitrophenylaminocarbonyl)-Hydrazine, 2 N, N??-bis-(p-nitrophenylaminocar-bonyl)-ethylenediamine and 3 N, N??-bis-(p-nitrophenylaminocarbonyl)-1, 3-propane-diamine are designed and synthesized. Studies of UV?Cvis spectra presented that 1 was an excellent sensor of F? and 2 was sensitive to H2PO4 ?. Unfortunately, 3 can not distinguish the anions investigated in this paper. The color changes of the hosts upon the addition of a variety of structurally different anions were also utilized as naked-eye detection which is very convenient. It also revealed significantly that the distance between two recognition sites of receptor had an immediate effect on the selectivity of receptor for anions, which had been confirmed by the 1H NMR titration and IR.  相似文献   

13.
Three new cobalt(Ⅱ) coordination compounds,[Co(3,3’-Hbpt)2(H2pm)(H2O)2]·2H2O(1),[Co(4,4’-Hbpt)(pm)0.5(H2O)]·3H2O (2) and [Co(3,4’-Hbpt)(pm) 0.5 (H2O)3]·2H2O(3)(3,3’-Hbpt=3,5-bis(3-pyridyl)-1H-1,2,4-triazole;4,4’-bpt=3,5-bis(4-pyridyl)1H-1,2,4-triazole,3,4’-Hbpt=3-(3-pyridyl)-5-(4’-pyridyl)-1H-1,2,4-triazole and H4pm=pyromellitic acid) have been synthesized by hydrothermal reactions.Single-crystal X-ray diffraction reveals that compound 1 has a one-dimensional (1D) chain network,2 exhibits a four-connected three-dimensional (3D) structure with 1D open channels encapsulated by water molecules,while 3 displays a regular two-dimensional (2D) architecture connected through 1D metal helical chains.In addition,the efficacy of compounds 1-3 as additives to promote the thermal decomposition of ammonium perchlorate (AP) is explored by differential scanning calorimetry (DSC).  相似文献   

14.
Experimental densities (ρ), viscosities (η), and speeds of sound (u) of the binary mixtures of n-dodecane with an alkan-1-ol (hexan-1-ol, heptan-1-ol, octan-1-ol) or an alkan-2-ol (hexan-2-ol, heptan-2-ol and octan-2-ol) were measured over the whole mixture composition range at T = 298.15 K. From these data, the excess molar volume ( $ V_{\text{m}}^{\text{E}} $ V m E ), deviations in viscosity (Δη), and excess isentropic compressibility ( $ \kappa_{S}^{\text{E}} $ κ S E ) have been calculated. The results were fitted by means of the Redlich–Kister equation, in order to estimate the binary coefficients and standard errors. Differences among these binary systems are ascribed to the different association abilities of the alkan-1-ols and alkan-2-ols. Experimental data on the constituted binaries were analyzed using McAllister’s multi-body interaction model, the Jouyban–Acree model, the Prigogine–Flory–Patterson theory, and the Bloomfield and Dewan model. The experimental and calculated quantities are used to study the nature of mixing behavior among the mixtures.  相似文献   

15.
A variety of heteroleptic ruthenium sensitizers have been engineered and synthesized because of their higher light-harvesting efficiency and lower charge-recombination possibility than the well known homoleptic N3 dye.As such,a great deal of attention has been focused on sensitizers with the general formula Ru(ancillary-ligand)(anchoring-ligand)(NCS) 2,among which important examples are Ru(4,4’-bis(5-hexylthiophen-2-yl)-2,2’-bipyridine)(4,4’-carboxylic acid-4’-2,2’-bipyridine)(NCS)2(C101) and Ru(N-(4-butoxyphenyl)-N-2-pyridinyl-2-pyridinamine)(4,4’-carboxylic acid-4’-2,2’-bipyridine)(NCS)2(J13).In order to simulate experimental conditions with different pH values,the photosensitizing processes of these sensitizers possessing different degrees of deprotonation (2H,1H to 0H) have been explored theoretically in this work.Their ground/excited state geometries,electronic structures and spectroscopic properties are first calculated using density functional theory (DFT) and time-dependent DFT (TDDFT).The absorption and emission spectra of all the complexes in acetonitrile solution are also predicted at the TDDFT (B3LYP) level.The calculated results show that the ancillary ligand contributes to the molecular orbital (MO) energy levels and absorption transitions.It is intriguing to observe that the introduction of a thiophene group into the ancillary ligand leads directly to the increased energy of the absorption transitions in the 380-450 nm region.The calculations reveal that although deprotonation destabilizes the overall frontier MOs of the chromophores,it tends to exert a greater influence on the unoccupied orbitals than on the occupied orbitals.Consequently,an obvious blue shift was observed for the absorptions and emissions in going from 2H,1H to 0H.Finally,the optimal degree of deprotonation for C101 and J13 has also been evaluated,which is expected to lead to further improvements in the performance of dye-sensitized solar cells (DSSCs) coated with such sensitizers.  相似文献   

16.
17.
Coordination compounds [Cd1.5I3(HMTA) · H2O] (I) and [CdI2(HMTA) · H2O] (II) are synthesized by the reaction of CdI2 with hexamethylenetetramine (HMTA, C6H12N4) with the 1: 1 ratio in ethanol, and their structures are determined. The crystals of compound I are triclinic, space group P $ \bar 1 $ , a = 8.027(1), b = 9.391(1), c = 10.382(1)?, ?? = 66.64(1)°, ?? = 86.18(1)°, ?? = 73.63(1)°, V = 749.2(1) ?3, ??calcd = 3.136 g/cm3, Z = 2. The crystals of compound II are triclinic, space group P $ \bar 1 $ , a =7.713(1), b = 8.192(1), c = 12.101(1)?, ?? = 80.32(1)°, ?? = 89.57(1)°, ?? = 7.30(1)°, V = 725.0(1) ?3, ??calcd = 2.402 g/cm3, Z = 2. Structure I includes two types of cadmium complexes. The Cd(1) atom is coordinated through the octahedral mode by three pairs of the I, N(HMTA), and O(H2O) atoms. The coordination polyhedron of the Cd(2) atom is a distorted tetrahedron (three I atoms and one N atom). The structure contains infinite strips consisting of tetranuclear cyclic fragments joined by the Cd(1) atoms due to the bridging iodine and nitrogen atoms. In structure II, the Cd atom is coordinated through the tetrahedral mode by two iodide ions and the N(HMTA) and O(H2O) atoms. The interaction between the complexes occurs due to hydrogen bonds O-H??N to form supramolecular chains along the direction [010]. In each HMTA molecule, one of four nitrogen atoms is a proton acceptor in the hydrogen bonds, one nitrogen atom is coordinated, and two N atoms are terminal. Compound II in the solid state has photoluminescence with maxima at 443, 470, and 518 nm.  相似文献   

18.
New oxamido-bridged binuclear CuII-CuII complexes, [Cu(Oxen)Cu(Bipy)2](ClO4)2 (I) and [Cu(Oxen)Cu(4,4??-Bipy)2(H2O)2](ClO4)2 (II) (Oxen is N,N??-bis(2-aminoethyl)oxamide dianion, Bipy = 2,2??-bipyridine, 4,4??-Bipy = 4,4??-bipyridine), have been constructed and structurally characterized by X-ray crystallography. In these two complexes, each Cu2+ ion is located in a slightly distorted square-pyramidal environment. Complex I is extended to two-dimensional by face-to-face ??-??-stacking with a distance of 3.648 II is raised to one-dimensional by face-to-face ??-??-stacking and intermolecular H-bonding interaction with distances of 3.651 and 2.767 I is also investigated.  相似文献   

19.
Synthetic approaches to 2-ethynyl-2-cyclopenten-1-ones (A) by dehydratation of the readily obtainable 2-(1-alkynyl)-2-hydroxy-cyclopentanones1 a and1 b were investigated. The synthesis of 2-(3,3,3-triphenylpropynyl)-2-cyclopenten-1-one (6) was achieved by reaction of 1-(3,3,3-triphenylpropynyl)-6-oxabicyclo[3.1.0]hexane (3 b) with HCl and CrO3-oxidation of the resulting 2-(3,3,3-triphenylpropynyl)-2-cyclopenten-1-ol (4).  相似文献   

20.
The ??-complexes [CuCl(C3H5NHC2H4CN)] (I), [(C3H5NH2C2H4CN)Cu2Cl3] (II), [((C3H5)2NHC2H4CN)CuCl2] (III), and [((C3H5)2NHC2H4CN)CuBr2] (IV) are obtained as single crystals by the ac electrochemical synthesis on copper wire electrodes from ethanolic solutions of 3-(allylamino)propanenitrile, 3-(diallylamino)propanenitrile, and CuX2 (X = Cl, Br). Their crystal structures are determined. The crystals of compounds I, III, and IV are monoclinic, space group P21/c, Z = 4. The crystals of compound II are triclinic, space group P $\bar 1$ , Z = 2. The unit cell parameters are a = 11.125(4), b = 8.769(4), c = 8.570(4) ?, ?? = 90.94(4)°, V = 835.9(6) ?3 (I); a = 6.2566(4), b = 7.5975(6), c = 11.1251(8) ?, ?? = 90.896(6)°, ?? = 92.827(5)°, ?? = 94.340(5)°, V = 526.57(7) ?3 (II); a = 11.656(4), b = 6.992(4), c = 14.681(5) ?, ?? = 100.89(4)°, V = 1174.9(9) ?3 (III); a =11.845(4), b = 7.282(4), c=14.855(5) ?, ?? = 100.37(4)°, V = 1260.4(9) ?3 (IV). The coordination mode of the Cu(I) atom in complex I includes two halogen atoms, the C=C bond, and the secondary amine N atom. The coordination environment in isostructural crystals of complexes III and IV is formed by the C=C bond and three halogen atoms as in complex II.  相似文献   

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