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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.
61

Estudo farmacognóstico e abordagem farmacológica de Justicia acuminatissima (MIQ.) BREMEK. (ACANTHACEAE)

Verdam, Maria Christina dos Santos 10 December 2009 (has links)
Made available in DSpace on 2015-04-22T22:14:08Z (GMT). No. of bitstreams: 1 DISSERTACAO - MARIA CHRISTINA.pdf: 2982107 bytes, checksum: a36683ab043be128b370fa7798f607e7 (MD5) Previous issue date: 2009-12-10 / Fundação de Amparo à Pesquisa do Estado do Amazonas / Justicia acuminatissima is a member of Acanthaceae family, known under the name of sara tudo and used in Amazonian in differents kinds of teas for treatment of inflammatory process. Despites the use, there isn´t in the literature information about the chemical constituints, farmacological action, or toxicological data. There is not information that gaves pharmacobotanical support that could help in correct identification. The present work did a farmacognostical approach of this specie, performing pharmacobotanical characterization, describing a phytochemical profile, evaluating the toxicity in the acute model of toxicity and addressing pharmacological activity attribuites to the plant, and correlated the same activities, such as platelet agrgregation, blood clotting and ulcerogenic capacity of it. The pharmacobotanical characterization provides tools for the correct identification, describing the kind of issues and this organizations in the vegetable with the structures that are present as if tricomas and stomatas. The phytochemical profile describes the presence of coumarines, steroids, saponins, tannins and cathequins. The coumarines presence is considerate very important because this presence is rare in the Acanthacea family. The pharmacological tests were based in the popular knowledge of the use of this specie, thus the extract were done with water as solvent, order to approach the use made by the population. The aqueous extract was safe in the acute toxicity model and the antiinflamatory activity was verify in the formalin model, and were confirmed in the rat paw edema. Besides, the extract don t show ulcerative power despites its antiinflamatory activity. The results in this work reaffirm the premiss that the popular uses serves as screening for the finding of natural products with benefitial activitys for man, since the antiinflamatory activity is in fact present in the aquos extract of the leaves oh this vegetable.The present work contribuites with the characterization of one more specie of the Amazonic flora, providing informations that can help in the correct use of medicinal plants and can be starting point for further studies. / Justicia acuminatissima (Miq.) Bremek. é um membro da família Acanthaceae, conhecida popularmente como sara tudo e utilizada na Amazônia sobre a forma de chás para tratamento de processos inflamatórios. Apesar do seu uso, não há na literatura informações acerca de seus constituintes químicos, ações farmacológicas, nem mesmo dados toxicológicos. Não há tão pouco, informações que forneçam suporte farmacobotânico permitindo sua correta identificação. Desta maneira, o presente trabalho realizou a abordagem farmacognóstica da espécie fazendo sua caracterização farmacobotânica, traçando um perfil fitoquímico da mesma, avaliando a toxicidade no modelo de toxicidade aguda e abordando farmacologicamente a atividade atribuída ao vegetal, além de atividades correlacionadas, tais como agregação plaquetária, coagulação sanguínea e a capacidade ulcerogênica. A caracterização farmacobotânica forneceu ferramentas para a correta identificação, descrevendo os tipos de tecido e sua organização no vegetal bem como as estruturas presentes, tais como os tricomas e estômatos. O perfil fitoquímico descreveu a presença de cumarinas, esteróides, saponinas, taninos condensados e catequinas, sendo a presença de cumarinas considerada de grande importância, dada a sua raridade na família Acanthaceae. Os ensaios farmacológicos realizados se basearam no conhecimento popular acerca do uso dessa espécie. O extrato empregado utilizou como solvente a água, visando se aproximar daquele feito pela população. O extrato aquoso se mostrou seguro no ensaio de toxicidade aguda e a atividade antiinflamatória foi verificada no modelo da formalina e confirmada no ensaio do edema de pata. Além disso, o extrato testado não apresentou poder ulcerativo, apesar de sua atividade antiinflamatória. Os resultados obtidos nesse trabalho reafirmaram a premisssa de que o uso popular serve como triagem para o achado de produtos de origem vegetal, com atividades benéficas ao homem, uma vez que a atividade antiinflamatória está de fato presente no extrato aquoso obtido a partir das folhas deste vegetal. O presente trabalho contribuiu com a caracterização de mais uma espécie da flora amazônica, fornecendo informações que podem auxiliar no correto uso de plantas medicinais e ser ponto de partida para estudos posteriores.
62

Estudo farmacognóstico do jambolão Syzygium cumini (L.) Skeels Myrtaceae / Pharmacological study of jambolão Syzygium cumini (L.) Skeels Myrtaceae

Ruggiero, Andrea de Andrade 23 March 2004 (has links)
Syzygium cumini (L.) Skeels (Myrtaceae) encontra uso na medicina tradicional como hipoglicemiante. Folhas mostram emprego adicional , no tratamento de úlceras pépticas, diarréias e hemorróidas. A dissertação apresenta descrições macro e microscópicas das folhas, acompanhadas de fotografias. Teores de flavonóides, saponinas e taninos foram determinados no extrato hidroetanólico liofilizado e na droga coletada no verão e outono. O óleo volátil foi analisado. O extrato foi avaliado quanto à atividade antimicrobiana, antioxidante e toxicidade aguda. Os flavonóides (0,53%-0,62%), saponinas (4,22%-8,64%) e taninos (3,47-4,15%) apresentaram teores elevados no outono. No extrato, teores de flavonóides: saponinas e taninos foram de 2,19%, 10,92% e 13.97%, respectivamente.α-pineno, α-terpineol, β-pineno e limoneno foram os componentes majoritários do óleo. O extrato não revelou sinais de toxicidade aguda, e não apresentou atividade contra bactérias e fungos até 1.000µ-g/mL. O extrato apresentou atividade antioxidante. Os dados obtidos contribuem para melhor conhecimento da espécie e no controle de qualidade. / Syzygium cumini (L.) Skeels (Myrtaceae) is a hipoglycemic in folk medicine. Its leaves are also used as anti-ulcer, anti-diarrheic and antihemorrhoid. This work brings macro and microscopic descriptions of the leaves, with photos. Flavonoids, saponins and tannins contents were determinated in the liophylizated hydroethanolic extract and in the drug collected in summer and falI. The volatile oil was analysed. The antimicrobial and antioxidant activities and the acute toxicity were avaliated . The flavonoids (0.53%-0.62%), saponins (4 .22%-8.64%) and tannins (3.47%-4-15%) showed their highest values in the fall sample. The contents of flavonoids, saponins and tannins in the extract were, 2.19%, 10.92% and 13.97%, respectively. α-pinene, α-terpineol, β and limonene were the major constituents of the oil. The extract showed no signs of acute toxicity nor was it active against bacteria and funghi up to 1,000µg/mL . The extract showed antioxidant activity. These data contribute for a better knowledge of the specie and quality control.
63

Anti-Neoplastic Effects of Extracts from Gnaphalium gracile on Colon, Pancreatic, and Prostate Cancer Cells

Canter, Joshua R 01 May 2015 (has links)
Over 4,000 flavonoids have been identified, and among these, many of them are known to possess cardioprotective, anti-inflammatory, antimicrobial, and antitumor effects. However, most of these properties have yet to be fully understood. In this study, extracts from Gnaphalium gracile, thought to possess a mixture of flavonoids, have been tested for cytotoxic activity on pancreatic (MiaPaca, Panc28), colon (HCT-116, Caco-2), and prostate (PC3, LNCaP), cancer cell lines. Polar extracts from the leaves of G. gracile have the most cytotoxic effect on these cancer cell lines, particularly the prostate cancer cell lines PC3 and LNCaP. Evidence suggests the extracts have antineoplastic effects on these cancer cells lines possibly due to differentiation status on pancreatic and colon cancer, but not prostate cancer. Cytotoxic activity is not dependent on tumorigenic potential. Further research is needed to identify the bioactive compounds within these extracts.
64

DISCOVERY OF NOVEL MURAYMYCIN ANTIBIOTICS AND INSIGHT INTO THE BIOSYNTHETIC PATHWAY

Cui, Zheng 01 January 2018 (has links)
New antibiotics with novel targets or mechanisms of action are needed to counter the steady emergence of bacterial pathogens that are resistant to antibiotics used in the clinic. MraY, a promising novel target for antibiotic development, initiates the lipid cycle for the biosynthesis of peptidoglycan cell wall, which is essential for the survival of most, if-not-all, bacteria. MraY is an enzyme that catalyzes the transfer and attachment of phospho-MurNAc-pentapeptide to a lipid carrier, undecaprenylphosphate. Muraymycins are recently discovered lipopeptidyl nucleoside antibiotics that exhibit remarkable antibiotic activity against Gram-positive as well as Gram-negative bacteria by inhibiting MraY. We conducted a thorough examination of the metabolic profile of Streptomyces sp. strain NRRL 30473, a known producer of muraymycins. Eight muraymycins were isolated and characterized by a suite of spectroscopic methods, including three new members of muraymycin family named B8, B9 and C5. Muraymycins B8 and B9, which differ from other muraymycins by having an elongated fatty acid side chain, showed potent antibacterial activity against Escherichia coli ∆tolC mutant and pM IC50 against Staphylococcus aureus MraY. Muraymycin C5, which is characterized by an N-acetyl modification of the disaccharide’s primary amine, greatly reduced its antibacterial activity, which possibly indicates this modification is used for self-resistance. In addition to the discovery of new muraymycins, eleven enzymes from the biosynthetic pathway were functionally assigned and characterized in vitro. Six enzymes involved in the biosynthesis of amino ribofuranosylated uronic acid moiety of muraymycin were characterized: Mur16, a non-heme, Fe(II)-dependent α-ketoglutarate: UMP dioxygenase; Mur17, an L-threonine: uridine-5′-aldehyde transaldolase; Mur20, an L-methionine:1-aminotransferase; Mur26, a low specificity pyrimidine nucleoside phosphorylase; Mur18, a primary amine-requiring nucleotidylyltransferase; Mur19, a 5-amino-5-deoxyribosyltransferase. A one-pot enzyme reaction was utilized to produce this disaccharide moiety and its 2′′-deoxy analogue. Two muraymycin-modifying enzymes that confer self-resistance were functionally assigned and characterized: Mur28, a TmrB-like ATP-dependent muraymycin phosphotransferase, and Mur29, a muraymycin nucleotidyltransferase. Notably, Mur28 preferentially phosphorylates the intermediate, aminoribofuranosylated uronic acid, in the muraymycin biosynthetic pathway to produce a cryptic phosphorylated-dissacharide intermediate. Mur23 and Mur24 were assigned as two enzymes that modify the cryptic phosphorylated intermediate by attachment of an aminopropyl group. Mur24 catalyzes the incorporation of butyric acid into the phosphorylated-disaccharide. Following the incorporation, Mur23 catalyzes a PLP-dependent decarboxylation. Finally, Mur15, which belongs to the cupin family, is functionally assigned as a non-heme, Fe(II)-dependent α-ketoglutarate dioxygenase that catalyzes the β-hydroxylation of a leucine moiety in muraymycin D1 to form muraymycin C1. Mur15 can also hydroxylate the γ-position of leucine moiety to muraymycins with fatty acid chain in β-position.
65

Bioactive Compounds from the Marine Sponge <i>Geodia barretti</i> : Characterization, Antifouling Activity and Molecular Targets

Sjögren, Martin January 2006 (has links)
<p>The marine sponge <i>Geodia barretti</i> produces a range of secondary metabolites. Two of these compounds were isolated and elucidated guided by their ability to inhibit settlement of cypris larvae of the barnacle <i>Balanus improvisus</i>. The compounds barettin (cyclo-[(6-bromo-8-en-tryptophan)-arginine]) as E/Z mixture and 8,9-dihydrobarettin (cyclo-[6-bromo-tryptophan)-arginine]) were determined by using mass spectrometry, nuclear magnetic resonance and quantitative amino acid analysis.The bioactivity of these brominated dipeptides is in the range of antifouling substances used today: EC<sub>50</sub> values of 0.9 µM (barettin) and 7.9 µM (8,9-dihydrobarettin). The compounds were successfully synthesised and then tested in a field experiment to evaluate their antifouling properties. The compounds were incorporated in four different commerical, non-toxic marine coatings. The concentrations of the compounds were 0.1 and 0.01% (w/w) and coated panels were exposed to field conditions for eight weeks. The experiment evaluated the effect of barettin and 8,9-dihydrobarettin on recruitment of the barnacle <i>B. improvisus</i> and the blue mussel <i>Mytilus edulis</i> (major Swedish foulers). The most efficient paint was a SPC polymer, for which the reduction of recruitment of <i>B. improvisus</i> was 89% with barettin (0.1%) and 61% with 8,9-dihydrobarettin (0.1%). For <i>M. edulis</i> the reduction of recruitment was 81% with barettin (0.1%) and 72% with 8,9-dihydrobarettin (0.1%) with the same SPC paint. Furthermore, 14 analogs of barettin and dipodazine were synthesised and tested for their ability to inhibit larval settlement. Two of the analogs have a barettin scaffold and twelve have a dipodazine scaffold. Six of the analogs displayed significant settlement inhibition with the most potent inhibitor being benzo[g]dipodazine (EC<sub>50</sub> value 0.034 µM). The effect of benzo[g]dipodazine was also shown to be reversible. Finally, an investigation of the mode of action was performed on 5-HT receptors. Barettin demonstrated a specific affinity to 5-HT<sub>2A</sub>, 5-HT<sub>2C</sub> and 5-HT<sub>4</sub>, while 8,9-dihydrobarettin interacted only with 5-HT<sub>2C</sub> of the receptor subtypes tested (5-HT<sub>1</sub>-5-HT<sub>7</sub>).</p>
66

Bioactive Compounds from the Marine Sponge Geodia barretti : Characterization, Antifouling Activity and Molecular Targets

Sjögren, Martin January 2006 (has links)
The marine sponge Geodia barretti produces a range of secondary metabolites. Two of these compounds were isolated and elucidated guided by their ability to inhibit settlement of cypris larvae of the barnacle Balanus improvisus. The compounds barettin (cyclo-[(6-bromo-8-en-tryptophan)-arginine]) as E/Z mixture and 8,9-dihydrobarettin (cyclo-[6-bromo-tryptophan)-arginine]) were determined by using mass spectrometry, nuclear magnetic resonance and quantitative amino acid analysis.The bioactivity of these brominated dipeptides is in the range of antifouling substances used today: EC50 values of 0.9 µM (barettin) and 7.9 µM (8,9-dihydrobarettin). The compounds were successfully synthesised and then tested in a field experiment to evaluate their antifouling properties. The compounds were incorporated in four different commerical, non-toxic marine coatings. The concentrations of the compounds were 0.1 and 0.01% (w/w) and coated panels were exposed to field conditions for eight weeks. The experiment evaluated the effect of barettin and 8,9-dihydrobarettin on recruitment of the barnacle B. improvisus and the blue mussel Mytilus edulis (major Swedish foulers). The most efficient paint was a SPC polymer, for which the reduction of recruitment of B. improvisus was 89% with barettin (0.1%) and 61% with 8,9-dihydrobarettin (0.1%). For M. edulis the reduction of recruitment was 81% with barettin (0.1%) and 72% with 8,9-dihydrobarettin (0.1%) with the same SPC paint. Furthermore, 14 analogs of barettin and dipodazine were synthesised and tested for their ability to inhibit larval settlement. Two of the analogs have a barettin scaffold and twelve have a dipodazine scaffold. Six of the analogs displayed significant settlement inhibition with the most potent inhibitor being benzo[g]dipodazine (EC50 value 0.034 µM). The effect of benzo[g]dipodazine was also shown to be reversible. Finally, an investigation of the mode of action was performed on 5-HT receptors. Barettin demonstrated a specific affinity to 5-HT2A, 5-HT2C and 5-HT4, while 8,9-dihydrobarettin interacted only with 5-HT2C of the receptor subtypes tested (5-HT1-5-HT7).
67

Distribution and Chemical Diversity of Cyclotides from Violaceae : Impact of Structure on Cytotoxic Activity and Membrane Interactions

Burman, Robert January 2010 (has links)
During the last decade there has been increased interest in the cyclotide protein family, which consist of a circular chain of approximately 30 amino acids, including six cysteines that form three disulfide bonds, arranged in a cyclic cystine knot motif. This thesis gives new insights in cyclotide distribution and occurrence in the plant family Violaceae, structure-activity relationships for cytotoxic effects, membrane disruption and adsorption on lipid membranes, and evaluates toxicity and anti-tumor activity in vivo. A large-scale analysis was done on over 200 samples covering 17 of the 23 genera in Violaceae, and cyclotides were positively identified in almost 150 of approximately 900 known species. Conclusions are that the Violaceae is an extremely rich source of cyclotides, and that they are ubiquitous among all species in that plant family. After investigating the cyclotides' cytotoxicity it was evident that the effects were immediate and occurred at low micromolar concentrations. To understand the relationships between structure and activity, approximately 30 cyclotides and cyclotide derivates were assayed for cytotoxicity. Results showed that the overall charge is of minor influence on activity and revealed a strong correlation between an intact hydrophobic molecular surface and cytotoxic effect. The cytotoxic activity is mainly due to interactions between peptides and target membranes, illustrated by prototypic cyclotides' ability to induce liposome leakage and adsorb to lipid membranes. Cyclotides were strongly lytic against zwitterionic liposomes, less when cholesterol was included, while for anionic liposomes, activity depend on the net charge of cyclotide. A similar pattern was observed for the adsorption of the cyclotides to anionic bilayers, in which strong lytic activity was coupled with high adsorption. To further evaluate cyclotides cytotoxic effects, in vivo studies were conducted, both for acute toxicity and anti-tumor efficacy in mice. Two different methods were used: hollow fiber method and traditional xenografts, but no significant anti-tumor effects were detected. The results indicate that anti-tumor effects are minor or absent at tolerable doses and that cyclotides have a very abrupt in vivo toxicity profile, with lethality after single injection at 2.0 mg/kg.
68

Ein handschriftlicher illustrierter Herbarius aus dem Emde des 15. Jahrhunderts und die medizinisch-botanische Literatur des Mittelalters /

Amsler, Hans. January 1900 (has links)
Thesis--Zürich. / "Arbeiten unter Leitung von Privatodozent Prof. Dr. H. E. Sigerist in Zürich."--head of title. Includes bibliographical references (p. 95).
69

Induction of LTB4 12-hydroxydehydrogenase (LTB4DH) by Radix Astragali and Radix Paeoniae Rubra: a study of theactive compounds and related biological functions

Wei, Lai, 魏来 January 2009 (has links)
published_or_final_version / Chinese Medicine / Master / Master of Philosophy
70

The antihypertentive effect of aqueous extract O Africana leaves.

Wang, Xu. January 2007 (has links)
<p>The incidence of cardiovascular diseases, including hypertension, is on the increase worldwide. Medicinal plants played an important role in the treatment of hypertension for centuries. Very few scientific studies have, however, been done to validate the use of these phytotherapies. O africana is on of the many phytotherapies that has been use indigenously for years to treat hypertension. The objectives of this study were to determine the most effective does of O africana aqueous extract which will reduce blood pressure / to determine whether chronic administration of O africana can be used to prevent and treat hypertension / to determine whether O africana exert its effects by modulation of the renin-angiotensin system.</p>

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