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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A multinuclear 1H, 13C and 11B solid-state MAS NMR study of 16- and 18-electron organometallic ruthenium and osmium carborane complexes

Barry, Nicolas P.E., Kemp, T.F., Sadler, P.J., Hanna, J.V. 20 February 2014 (has links)
Yes / The first 1H, 13C, 31P and 11B solid state MAS NMR studies of electron- deficient carborane-containing ruthenium and osmium complexes [Ru/Os(p-cym)(1,2-dicarba-closo-dodecaborane-1,2- dithiolate)] are reported. The MAS NMR data from these 16-electron complexes are compared to those of free carborane-ligand and an 18-electron triphenylphosphine ruthenium adduct, and reveal clear spectral differences between 16- and 18-electron organometallic carborane systems in the solid state. / We thank the Swiss National Science Foundation (grant no. PA00P2-145308 to NPEB), the ERC (grant no. 247450 to PJS), EPSRC (grant no. EP/F034210/1) and EC COST Action CM1105 for support. JVH thanks EPSRC and the University of Warwick for partial funding of the solid state NMR infrastructure at Warwick, and acknowledges additional support obtained through Birmingham Science City: Innovative Uses for Advanced Materials in the Modern World (West Midlands Centre for Advanced Materials Project 2), with support from Advantage West Midlands (AWM) and partial funding by the European Regional Development Fund (ERDF).
2

AplicaÃÃo de tÃcnicas contemporÃneas de ressonÃncia magnÃtica nuclearno estudo fitoquÃmico de Aspidosperma ulei Markgf / Application of techniques contemporaries of nuclear magnetic resonance in the fitoquÃmico investigations of Aspidosperma Ulei Markgf

Daniel Esdras de Andrade Uchoa 20 December 2006 (has links)
CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / O material vegetal (raiz e caule) de Aspidosperma ulei Markgf (Apocinaceae), popularmente conhecida como PÃtia, foi coletada na localidade de Garapa, no municÃpio de Acarape, CearÃ. Neste trabalho, alÃquotas dos extratos etanÃlicos da casca da raiz e da casca do caule de A. ulei foram submetidas a cromatografias sobre sephadex e/ou sÃlica gel, e CLAE, possibilitando o isolamento dos alcalÃides (+)-20(S)uleÃna (AU-1). (+)-20S-dasicarpidona (AU-2), (-)-16, 19-dimetil-3, 5, 14, 21-tetra-hidro-elipticina (AU-3), (-)-β-ioimbina (AU-4), (-)-20(S)-N-desmetil-uleÃna (AU-5), (+)-15(S)-18-hidroxi-20(Z)-16, 17-nor-subincanadina E (AU-7) e (+)-15(S)-20(Z)-16, 17-nor-subincanadina E (AU-8), e o derivado do inositol (-)-D-1-O-metil-myo-inositol (AU-6). Desses alcalÃides, (+)-15(S)-18-hidroxi-20(Z)-16, 17-nor-subincanadina E (AU-7) e (+)-15(S)-20(Z)-16, 17-nor-subincanadina E (AU-8) sÃo inÃditos na literatura como produtos naturais, embora o Ãltimo jà tenha sido caracterizado como intermediÃrio de sÃnteses de alcalÃides de Stryenos. A identificaÃÃo e caracterizaÃÃo dos compostos isolados foi realizada por tÃcnicas espectromÃtricas como I. V e RMN uni- e bidimensional, inclusive tÃcnicas contemporÃneas como HSQC editado, HSQC-TOCSY e 1H,X-HMBC (X = 13C ou 15N). Estudos farmacolÃgicos de uma fraÃÃo do extrato etanÃlico da casca da raiz de A. ulei, rica em alcalÃides, realizados no Departamento de Fisiologia e Farmacologia da UFC, pelo Prof. V. S. N. Rao, demonstrou o efeito prÃ-erectil dessa fraÃÃo em ratos, em trÃs casos distintos: ereÃÃo peniana, tipo-ereÃÃo e similar a ereÃÃo. InjeÃÃo intraperitonial da fraÃÃo (25 a 50 mg/Kg), possibilitou observar efeitos semelhantes ao efeito observado para a ioimbina (2 mg/Kg). Esses estudo apÃia o uso tradicional de extratos de espÃcies de Aspidosperma em deficiÃncias orgÃnicas erÃteis. / The material (root and stem) of Aspidosperma ulei Markgf (Apocinaceae), popularly known as PitiÃ, was collected in the locality of Garapa, Acarape County, CearÃ. In this work, aliquots of the ethanol extracts of the root and of the stem barks of A. ulei were submitted to chromatographic analysis in sephadex and silica gel , and CLAE, making possible the isolation of the alkaloids (+)-20(S)uleÃne (AU-1). (+)-20(S)-dasicarpidone (AU-2), (-)-16, 19-dimethyl-3, 5, 14, 21-tetra-hydro-ellipticine (AU-3), (-)-β-yohimbine (AU-4), (-)-20(S)-N-demethyl-uleine (AU-5), (+)-15(S)-18-hidroxy-20(Z)-16, 17-nor-subincanadine E (AU-7) and (+)-15(S)-20(Z)-16, 17-nor-subincanadine E (AU-8), and a inositol derivative, the (-)-D-1-O-methyl-myo-inositol (AU-6). The alkaloid, (+)-15(S)-18-hidroxy-20(Z)-16, 17-nor-subincanadine E (AU-7) and (+)-15(S)-20(Z)-16, 17-nor-subincanadine E (AU-8) are related for the first time as natural product, but the last one has been characterization as an intermediary of the Stryenosâ alkaloids synthesis. The identification and characterization of the isolated compounds was accomplished by IR and 1D and 2D NMR techniques, mainly contemporary techniques as edited HSQC, HSQC-TOCSY and 1H,X-HMBC (X = 13C or 15N). Pharmacological studies of an alkaloid rich fraction of the root bark of A. ulei, accomplished in the Departamento de Fisiologia e Farmacologia da UFC by Prof. V. S. N. Rao. Demonstrated the pro-erectile effect of that fraction in three cases: penile erection, erection-like and genital grooming in mice. Intraperitoneal injection of the fraction (25 to 50 mg/Kg), shown all three different responses similar to yohimbine (2 mg/Kg). This study further supports the traditional use of extracts from Aspidosperma species in erectile dysfunctions.
3

Study Chemical and Biological Margaritopsis carrascoana Wright (Rubiaceae) / Estudo QuÃmico e BiolÃgico de Margaritopsis carrascoana Wright (Rubiaceae).

Raimundo Regivaldo Gomes do Nascimento 16 December 2014 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Margaritopsis carrascoana is a small shrub belonging to the Rubiaceae family and endemic from northeastern of Brazil flora growing in the sandy soils of the region of Ibiapaba and Araripe plateaus â Cearà state. The absence of reports of phytochemical studies related to this species, combined with occurrence of bioactive alkaloids in the genus, motivated us to perform chemical study. The plant specimen was collected in Araripe plateu, in MoreilÃndia-PE county. The phytochemical investigation of the ethanolic extract from the stems yielded the alkaloids calycosidine, hodgkinsine, N-8â-formyl-calycosidine and N-8â-methyl-N-1â-desmethylisocalycosidine, besides neolignan dihydrodehydrodiconiferyl alcohol 4-O-β-D-glucopyranoside, the flavonol luteolin 7-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl, the triterpenes lupeol and ursolic acid, and the mixture of β-sitosterol and stigmasterol steroids, as aglycones and glycosylated. From the ethanolic extract of the leaves were isolated the flavonoid luteolin 7-O-[β-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside, chrysoeriol 7-O-[β-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside, luteolin 7-O-{β-D-apiofuranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl} and luteolin 7-O-{α-L-rhamnopyranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl}. The alkaloids N-8"-formyl-calycosidine, N-8â-methyl-N-1â-desmethylisocalycosidine, luteolin 7-O-{β-D-apiofuranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl} and luteolin 7-O-{α-L-rhamnopyranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyra-nosyl}, are being reported for the first time in the literature, and the other secondary metabolites are unprecedented in the genus Margaritopsis. The secondary metabolites were isolated using classical chromatography techniques; including adsorption chromatography on silica gel, exclusion chromatography on Sephadex LH-20, reverse phase chromatography (C-18), and high performance liquid chromatography (HPLC). For structural characterization were used infrared spectroscopy, mass spectrometry and nuclear magnetic resonance techniques including uni (1H NMR and 13C NMR and DEPT 135) and two-dimensional experiments (HMBC, HSQC, COSY and NOESY), and comparison with the literature data. In addition, the flavonoids flavonol luteolin 7-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl, luteolin 7-O-[β-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside, luteolin 7-O-{β-D-apiofuranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl} and luteolin 7-O-{α-L-rhamnopyranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl, sho-wed antioxidant activity greater than the BHT and quercetin standards, while ethanol extracts of stems and leaves showed inhibitory activity on the acetylcholinesterase enzyme. On the other hand, hodgkinsine showed potent cytotoxic activity against ovary, glioblastoma and colon cancer cells lines. The ethanol extract of the leaves and its alkaloidal fraction were submitted to nociception test and yielded good results. The ethanolic extract of the leaves was subjected to gastric antiulcer activity test, leading to a significant reduction in gastric lesions induced by ethanol in mice. / Margaritopsis carrascoana à um pequeno arbusto pertencente à famÃlia Rubiaceae e endÃmico da flora do Nordeste brasileiro, que cresce em solos arenosos do planalto da Ibiapaba e serra do Araripe - CearÃ. A ausÃncia de relatos acerca de estudos fitoquÃmicos relacionados à espÃcie, aliada a ocorrÃncia de alcalÃides bioativos no gÃnero, nos motivou ao seu estudo quÃmico. Desta forma, o espÃcimen vegetal foi coletado na chapada do Araripe, municÃpio de MoreilÃndia-PE. A investigaÃÃo fitoquÃmica do extrato etanÃlico dos talos resultou no isolamento dos alcalÃides calicosidina, hodgkinsina, N-8â-formilcalicosidina e N-8â-metil-N-1â-desmetilisocalicosidina, da neolignana Ãlcool 4-O-β-D-glicopiranosil-di-hidro-desidrodiconiferÃlico, do flavonÃide 7-O-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil luteolina, dos triterpenos lupeol e o Ãcido ursÃlico, e da mistura de esterÃides β-sitosterol e estigmasterol, como agliconas e nas formas glicosiladas. A partir do estudo do extrato etanÃlico das folhas foram isolados os flavonÃides 7-O-[β-D-glicopiranosil-(1→6)-β-D-apiofuranosil] luteolina, 7-O-[β-D-glicopiranosil-(1→6)-β-D-apiofuranosil] crisoeriol, 7-O-{β-D-apiofuranosil-(1→6)-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina e 7-O-{α-L-ramnopiranosil - (1→6) - [α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina. Os alcalÃides N-8â-formilcalicosidina e N-8â-metil-N-1â-desmetilisocalicosidina, e os flavonÃides 7-O-{β-D-apiofuranosil-(1→6)-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina e 7-O-{α-L-ramnopiranosil-(1→6)-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina, estÃo sendo relatados pela primeira vez na literatura, enquanto todas as demais substÃncias possuem carÃter inÃdito no gÃnero Margaritopsis. O isolamento dos metabÃlitos secundÃrios foi conduzido atravÃs de tÃcnicas cromatogrÃficas clÃssicas, incluindo cromatografia de adsorÃÃo em gel de sÃlica, cromatografia por exclusÃo molecular em Sephadex LH-20, cromatografia de fase reversa (C-18) e cromatografia lÃquida de alta eficiÃncia (CLAE). Para a caracterizaÃÃo estrutural foram utilizadas tÃcnicas espectroscÃpicas utilizando infravermelho, espectrometria de massas e ressonÃncia magnÃtica nuclear, incluindo tÃcnicas uni (RMN 1H e RMN 13C e DEPT 135) e bidimensionais (HMBC, HSQC, COSY e NOESY), alÃm de comparaÃÃo com dados descritos na literatura. Em adiÃÃo, os flavonÃides 7-O-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil luteolina, 7-O-[β-D-glicopiranosil-(1→6)-β-D-apiofuranosil] luteolina, 7-O-{β-D-apiofuranosil-(1→6)-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina e 7-O-{α-L-ramnopiranosil-(1→6) - [α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina apresentaram atividade antioxidante maior que os padrÃes BHT e quercetina, enquanto os extratos etanÃlicos dos talos e folhas apresentaram atividade inibidora da enzima acetilcolinesterase. Por outro lado, o alcaloide hodgkinsina apresentou potencial citotÃxico frente Ãs cÃlulas de ovÃrio, glioblastoma e colon. No teste de nocicepÃÃo, realizado com o extrato etanÃlico das folhas e a fraÃÃo alcalÃidica, foram observados resultados positivos para ambas as fraÃÃes. O extrato etanÃlico das folhas foi submetido a teste de atividade antiÃlcera gÃstrica, levando a uma reduÃÃo significativa da Ãrea de lesÃo gÃstrica induzida pelo etanol em camundongos.
4

Estudo CromatogrÃfico, EspectroscÃpico e FarmacolÃgico de Alcaloides Plumeranos das Sementes de Aspidosperma pyrifolium Mart. / Estudo CromatogrÃfico, EspectroscÃpico e FarmacolÃgico de Alcaloides Plumeranos das Sementes de Aspidosperma pyrifolium Mart.

Patricia Coelho do Nascimento Nogueira 08 September 2014 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Este trabalho relata o estudo fitoquÃmico das sementes de Aspidosperma pyrifolium (Apocinaceae), descrevendo o isolamento e a determinaÃÃo estrutural de um alcaloide inÃdito com esqueleto plumerano rearranjado, o (-)-(3S,7S,21R)-rel-(3αH)-15(14→3)-abeo-2,16,17,20,6,7-hexahidro-15H,8aH,16a,20a-etano-1H-indolizino[3,1-cd]carbazol, alÃm de onze compostos conhecidos, seis alcaloides plumeranos identificados como aspidospermina, desmetoxiaspidospermina, pirifolina, 15-desmetoxipirifolina, aspidofractinina e N-acetilaspidofractinina; um alcaloide tetra-hidro-β-carbolÃnico, a N-metilacuamidina; dois iridoides glicosilados, Ãcido logÃnico e loganina; um derivado do Ãcido salicÃlico, o Ãcido 2-hidrÃxi-3-O-β-D-glicopiranosilbenzÃico; e um derivado metilado do inositol, o 2-O-metil-L-quiro-inositol. Os compostos foram isolados por tÃcnicas cromatogrÃficas, principalmente a Cromatografia LÃquida de Alta EficiÃncia, e suas estruturas foram determinadas atravÃs de anÃlises por RMN, uni e bidimensionais, IV e EMAR, alÃm da comparaÃÃo com dados da literatura. Apesar de jà descritos na literatura, cinco compostos sÃo relatados pela primeira vez para a espÃcie, e um està sendo relatado pela primeira vez como produto natural, de origem vegetal. A revisÃo dos dados de RMN da literatura de alguns alcaloides isolados, e as correspondentes correlaÃÃes estruturais, juntamente com um levantamento bibliogrÃfico (de 1973 a 2013) dos dados de RMN 13C de alcaloides plumeranos isolados da famÃlia Apocinaceae, tambÃm sÃo descritos neste trabalho. A fraÃÃo aquosa resultante da partiÃÃo lÃquido-lÃquido do extrato etanÃlico das sementes de A. pyrifolium, fonte da maioria dos compostos isolados, apresentou atividades antinociceptiva e anti-inflamatÃria nos testes de formalina, contorÃÃo abdominal induzida pelo Ãcido acÃtico e edema de pata por carragenina. / This work reports the phytochemical analysis from seeds of Aspidosperma pyrifolium (Apocynaceae), describing the isolation and the structural characterization of a unknown alkaloid with a rearranged plumeran skeleton, the (-)-(3S,7S,21R)-rel-(3αH)-15(14→3)-abeo-2,16,17,20,6,7-hexahydro-15H,8aH,16a,20a-ethano-1H-indolizino[3,1-cd]carbazole, in addition to eleven known compounds, six plumeran alkaloids identified as aspidospermine, demethoxyaspidospermine, pirifoline, 15-demethoxypirifoline, aspidofractinine and N-acetylaspidofractinine; a tetrahydro-β-carboline alkaloid, the N-methylakuammidine; the glycosides of two iridoids, loganic acid and loganin; a salycilic acid derivative, 2-hydroxy-3-O--D-glucopyranosylbenzoic acid; and a methyl inositol derivative, the 2-O-methyl-L-chiro-inositol. The compounds were isolated by chromatographic techniques, especially High Performance Liquid Chromatography, and their structures were characterized by 1D and 2D NMR spectroscopy, FT-IR and HRESIMS, and comparison with data from literature. Altough already reported in the literature, five compounds are being reported for the first time for the species, and one is being reported from a natural source. The NMR data, and the correspondent assignments of some alkaloids already reported in the literature, together with a bibliographic survey (from 1973-2013) of the 13C NMR data of plumeran alkaloids isolated from the Apocynaceae family, are presented in this work. The residual aqueous fraction of the liquid-liquid partition of the ethanol extract from seeds of A. pyrifolium, source of most compounds isolated, showed antinociceptive and anti-inflammatory activities in the formalin test, abdominal writhing induced by acetic acid, and paw edema induced by carrageenan.
5

Novel NMR Methods for Fast Data Acquisition : Application to Metabolomics

Pudakalakatti, Shivanand January 2014 (has links) (PDF)
Synopsis My research work is focused on: (i) development of novel Fast NMR methods in solution state and their application to metabolomics and small molecules. (ii) NMR based metabolic study of human IVF to assess embryo viability for implantation. The major components of the embryo growth media were identified for evaluating the embryo quality. Described below are the projects carried out towards the dissertation of my PhD. Chapter 1 describes NMR methods which are the foundation stones for new Fast NMR methods developed. Typical 1D and 2D NMR experiments used in metabolomics and statistical methods for analysis are described. A few applications of metabolomics are also covered in the chapter. Chapter 2 describes a new Fast NMR method based on polarization sharing and parallel acquisition using the dual receiver system. The method developed helps in acquiring simultaneously three 2D NMR spectra: 2D [13C-1H] HETCOR, 2D [1H-1H] TOCSY and 2D [13C-1H] HSQC-TOCSY in a single data set. This method achieves a time saving of about two fold. All the experiments are acquired on molecules with natural abundance of 13C. The method was used to assign the side chain atoms (1H and 13C) of two important peptides. i) 12 amino acid residue peptide, which is a part of central linker domain of Human Insulin like Growth Factor Binding Protein-2 known to play a vital role in the IGF system and ii) a 18 amino acid residue peptide which acts as an antimicrobial agent. Chapter 3 describes extension of the Fast NMR method described in chapter 2. The method is combined with G-matrix Fourier Transform NMR spectroscopy. In this method we have acquire simultaneously two 2D NMR experiments and one reduced dimensional 3D experiment. The three experiments are 2D [13C-1H] HETCOR, 2D [1H-1H] TOCSY and GFT (3,2)D [13C-1H] HSQC-TOCSY, which provide complementary information for rapid assignments. GFT (3,2)D [13C-1H] HSQC-TOCSY gives 3D correlations in a 2D manner facilitating high resolution and unambiguous assignments. The experiments were applied for complete assignment of 21 unlabeled metabolite mixtures corresponding to the Innovative Sequential medium (ISM1) used for culturing human embryos for IVF. Further, a 13C multiplicity edition block is added to the method to simplify the resonances assignment in GFT (3,2)D [13C-1H] HSQC-TOCSY. Taken together, experiments provide time gain of order of magnitudes compared to conventional data acquisition. Chapter 4 of the thesis describes a metabolomics study of Human in-vitro fertilization to assess viable embryos of implantation potential using NMR as non-invasive tool. NMR study included the analysis of 127 embryo culture media (Innovative Sequential Media-1) and 29 controls (culture media without embryo) of both day-2 and day-3 transferred. The embryos were divided into 3 categories 1) implanted (successful) 2) transferred not-implanted (unsuccessful) 3) not transferred based on morphological studies. All NMR experiments were acquired with CPMG (T2 filter) incorporated in 1D 1H presaturation pulse scheme. The study was based on estimation of lactate, pyruvate and alanine levels in the embryo culture media (ISM1). The study reveals higher uptake of pyruvate and high pyruvate/alanine ratios in case of implanted embryos compared to one which failed to implant. Present study provides pyruvate/alanine ratio as a biomarker to select the embryos with high implantation potential. The method combined with morphology based assessment or with other biomarkers can be serve as a powerful tool to assess the embryo quality. Chapter 5 describes a novel NMR method for rapid characterization of translation diffusion of molecules in solution either in mixture or pure form. Unlike acquisition of several 2D [13C-1H] HSQC experiments with varying gradients to get diffusion measurement, a single 2D [13C-1H] HSQC is sufficient to measure the diffusion coefficients which is in the linewidths of peaks. The method uses the idea of accordion NMR spectroscopy, wherein gradients are linearly co-incremented with 13C chemical shift evolution period during t1. The methodology speeds up the acquisition by replacing series of 2D [13C-1H] HSQC with single 2D constant time [13C-1H] HSQC. The method was used to monitor the diffusion of metabolites in a time-resolved manner during polymerization of SDS-PAGE gel. Using this method, it was possible to detect the presence of oligomers of diphenylalanine (FF) during its self assembly to form nanotubular structures.

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