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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.
11

METABÓLITOS SECUNDÁRIOS EM VERNONIA TWEEDIEANA BAKER / SECUNDARY METABOLIC OF VERNONIA TWEEDIEANA BAKER

Zanon, Ricardo Basso 07 April 2006 (has links)
The species Vernonia tweedieana Baker is an herbaceous plant widely distributed in the plains of Paraguai, Argentina and south of Brazil and popularly known as assa-peixe . This plant is used in traditional medicine as an expectorant medicament. So far, this plant was not studied on the phytochemical and biological point of view. This work is a contribution to the phytochemical study of the Asteraceae. The leaves of V. tweedieana Baker were collected in march of 2004, in Ijuí Rio Grande do Sul, Brazil, and identified by Dr. Geraldo C. Coelho (UNIJUÍ). The respective voucher specimen was deposited in the herbarium of the Federal University of Santa Maria (UFSM)-RS (code SMDB 9536). The leaves (1.900 g) were dried in an air circulating stove at 40 ºC, pulverized in mill and extracted by maceration with 65% EtOH at room temperature for seven days. The ethanolic extract was filtered and the ethanol was removed. Finally, the extract was retake in water and partitioned using organics solvents with increased polarity: CH2Cl2, AcOEt and n-BuOH. We report the isolation and identification of six constituents of the CH2Cl2 fraction: the triterpenes a-amyrin, b-amyrin and lupeol and the steroids b- sitosterol, stigmasterol and spinasterol. The flavanone eriodictyoI was isolated from the AcOEt fraction. The constituents were identified through spectral data of the infra-red, GC-MS, 1H-NMR, 13C-NMR and DEPT. No deaths and other signs of toxicity and adverse effect were observed in the evaluation of acute toxicity with doses up to 5.000 mg/kg, that is the maximum dose for acute oral toxicity test for extract of plants. Also, through DPPH method, AcOEt and n-BuOH fractions of the plant showed good antioxidant activity with IC50 22.52 and 17.44 mg/mL, respectively. / O uso de plantas medicinais sempre teve uma importância vital no cotidiano da humanidade. No entanto, apenas uma pequena parte destas já foram estudadas e tiveram suas ações farmacológicas comprovadas cientificamente. Um exemplo de planta ainda desconhecida quimicamente é Vernonia tweedieana Baker (Asteraceae), vulgarmente conhecida como assa-peixe. É uma planta característica da região Sul do Brasil que é usada popularmente para o tratamento de doenças respiratórias, principalmente pelas suas propriedades expectorantes. Este trabalho descreve o isolamento e identificação de seis constituintes químicos presentes no extrato CH2Cl2 e de um no extrato AcOEt das folhas de Vernonia Tweedieana Baker. As folhas foram coletadas em março de 2004, no município de Ijuí RS. A espécie foi localizada e identificada pelo Prof. Dr. Geraldo C. Coelho (DeBQ-UNIJUÍ). Material testemunha encontra-se depositado no Herbário do Departamento de Biologia da UFSM sob o registro n° SMDB 9536. O material vegetal seco e moído (1.900 g) foi macerado utilizando como solvente etanol:água (65:35, v/v). Após sete dias o extrato foi filtrado e concentrado sob pressão reduzida para remover o etanol. Fez-se fracionamento desse extrato bruto com solventes orgânicos de polaridades crescentes (CH2Cl2, AcOEt, n- BuOH). Da fração CH2Cl2 caracterizou-se os triterpenos a e b-amirinas e lupeol, ainda os esteróides b-sitosterol, estigmasterol e espinasterol; e da fração AcOEt o flavonóide eriodictiol. Os compostos isolados foram analisados por CG-EM-IE, IV, RMN de 1H e RMN de 13C e seus dados espectroscópicos foram comparados com os obtidos da literatura. Ainda, na avaliação da toxicidade aguda foi verificado que nenhum dos extratos apresentou toxicidade em doses até 5.000 mg/mL. Também, pelo método do DPPH, foi constatada atividade antioxidante para as frações AcOEt e n-BuOH da planta, apresentando IC50 de 22,52 e 17, 44 mg/mL, respectivamente.
12

The Preparation and Characterization of Cyclodextrin:Sterol Inclusion Complexes as Anti-Tumor Therapeutics

Cowins, Janet V 15 December 2015 (has links)
An inclusion complex between β-cyclodextrin and insoluble guest compounds has been reported by several researchers. The main purpose of forming an inclusion complex between β-CD and sparingly soluble guests is to enhance the guest’s solubility and mask its undesirable properties. Preliminary studies have shown that when conjugated with target-specific moieties, these inclusion complexes can be used in pharmaceutical applications for drug delivery. β-Sitosterol, a plant sterol, has been well documented to reduce tumor cell growth and migration as well as exhibit apoptotic characteristics. An issue with this plant sterol and most pharmaceutical compounds is their lack of solubility. In this study, we propose that an inclusion complex will enhance the solubility of this sterol and change the physicochemical properties of the sparingly soluble guest. We first prepared the β-CD:β-Sitosterol inclusion complex and characterized the samples in both solid and solution state. The complex was characterized using FT-IR, DSC, SEM and NMR. IR studies of the inclusion complex and physical mixture revealed changes in the characteristic peaks of the inclusion complex suggestive of the formation of a new compound. 1HNMR studies revealed an upfield resonance shift of β-CD internal protons (H3 and H5) as an equal molar ratio of β-Sitosterol is introduced into the β-CD mixture. 2D NOESY NMR studies suggest that the initial sites of interaction of β-CD and β-Sitosterol occur between the aliphatic tail of β-Sitosterol and H3 of β-CD. 2D ROESY NMR reveals that the cyclic head of β-Sitosterol also interacts with the cavity of β-CD suggesting that β-Sitosterol may be completely encapsulated inside β-CD’s cavity. From these initial studies, we hypothesize that the β-CD-PEG-FA will facilitate absorption of β-Sitosterol and increase the drug delivery vehicle’s solubility as a whole. Since most tumor cells over-express folic acid, inclusion of folic acid in the construct of the vehicle will direct these sterols to tumor sites. β-cyclodextrin-PEG, a precursor to the bio-conjugate for antitumor delivery of sterols, was synthesized and characterized.
13

Linker-based Lecithin Oral Drug Delivery Systems

Chu, Jacquelene 04 December 2012 (has links)
In this study, pharmaceutical-grade and food-grade linker-based lecithin self-emulsifying delivery systems (SEDS) were developed with a combination of lipophilic and hydrophilic linkers. These additives at suggested concentrations are safe for pharmaceutical and food applications. The ratio of surfactant lecithin and linkers in these systems was optimized to develop surfactant in oil preconcentrates. The preconcentrates containing different surfactant concentrations and oil were diluted with fed state simulated intestinal fluid to produce pseudo-ternary phase diagrams and to identify the formulations that produced self-emulsifying or self-microemulsifying delivery systems. Optimal SEDS preconcentrates were evaluated using a dialyzer model to simulate intestinal uptake. An uptake of 39.6 mg/cm2 for the pharmaceutical-grade SEDS was obtained within 72 minutes, which promises substantial improvement in the bioavailability of hydrophobic actives. The optimal uptake of 12.2 mg/cm2 for food-grade SEDS suggests enhancement in the bioavailability of omega-3 fatty acids.
14

Fate of phytosterols in pulp and paper wastewater treated in a simulated aerated stabilization basin

Dykstra, Christine M. 27 August 2014 (has links)
Phytosterols are steroid chemicals produced by plants for the purposes of membrane function and hormone production. Phytosterols can cause endocrine disruption in aquatic species at very low concentrations and are suspected of contributing to endocrine disruption linked to pulp and paper effluent. Wastewater from the pulp and paper industry is often treated biologically in aerated stabilization basins (ASBs) that expose phytosterols to a range of redox zones. Phytosterol removal in ASBs varies and stigmasterol has even been shown to increase across the treatment system. Little is known about the microbial processes that occur within ASBs and their effect on phytosterol removal. The objective of this research was to assess the biotransformation potential of phytosterols in a simulated ASB treatment system and to improve understanding of the processes that occur within the various redox zones and their impact on the removal of phytosterols. To assess the biotransformation of phytosterols under aerobic conditions, three assays were conducted using a stock aerobic culture fed with pulp and paper wastewater. The assays tested three conditions: phytosterols present as a sole added carbon source, phytosterols with dextrin as an added carbon source, and phytosterols with ethanol as a solubilizing agent and added carbon source. Phytosterol biotransformation was found to be limited by low phytosterol solubility. When solubilized, phytosterol removal occurred in two phases: an initial near-linear removal, followed by accelerated removal during the culture's stationary stage, possibly due to the release of extracellular cholesterol oxidase. The anoxic and anaerobic biotransformation of phytosterols was examined through a series of three semi-batch cultures maintained under nitrate-reducing, sulfate-reducing and fermentative/methanogenic conditions, all developed from stock cultures fed with pulp and paper wastewater. Phytosterol removal was significant in the nitrate-reducing culture, although microbial activity and phytosterol removal declined in later stages. Phytosterol removal was also observed in the sulfate-reducing culture, although there was a significant lag period before removal occurred. No phytosterol removal was observed in the fermentative/methanogenic culture. Phytosterol biotransformation was also examined in the context of a lab-scale ASB fed continuously with pulp and paper wastewater. The steady-state ASB effluent and sediment characteristics were examined over three hydraulic retention times (HRTs). Effluent quality was not significantly affected by a change in HRT but sediment characteristics were significantly affected and, at shorter HRTs, phytosterols accumulated in the sediment. Wastewater bioassays demonstrated the release of phytosterols during the breakdown of solids. This research improves the understanding of biological processes within ASBs and their effect on phytosterol removal.
15

Linker-based Lecithin Oral Drug Delivery Systems

Chu, Jacquelene 04 December 2012 (has links)
In this study, pharmaceutical-grade and food-grade linker-based lecithin self-emulsifying delivery systems (SEDS) were developed with a combination of lipophilic and hydrophilic linkers. These additives at suggested concentrations are safe for pharmaceutical and food applications. The ratio of surfactant lecithin and linkers in these systems was optimized to develop surfactant in oil preconcentrates. The preconcentrates containing different surfactant concentrations and oil were diluted with fed state simulated intestinal fluid to produce pseudo-ternary phase diagrams and to identify the formulations that produced self-emulsifying or self-microemulsifying delivery systems. Optimal SEDS preconcentrates were evaluated using a dialyzer model to simulate intestinal uptake. An uptake of 39.6 mg/cm2 for the pharmaceutical-grade SEDS was obtained within 72 minutes, which promises substantial improvement in the bioavailability of hydrophobic actives. The optimal uptake of 12.2 mg/cm2 for food-grade SEDS suggests enhancement in the bioavailability of omega-3 fatty acids.
16

Síntese de ésteres derivados de triterpenos e esteroides com potencial atividade biológica

Santos, Marcelo Álison Sousa dos 03 July 2015 (has links)
Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2016-02-23T14:51:45Z No. of bitstreams: 1 Versão final 1.pdf: 11990349 bytes, checksum: 5aa2ee24e8db0a1ccd54b5641e0695b2 (MD5) / Approved for entry into archive by Ana Hilda Fonseca (anahilda@ufba.br) on 2016-05-10T16:54:19Z (GMT) No. of bitstreams: 1 Versão final 1.pdf: 11990349 bytes, checksum: 5aa2ee24e8db0a1ccd54b5641e0695b2 (MD5) / Made available in DSpace on 2016-05-10T16:54:19Z (GMT). No. of bitstreams: 1 Versão final 1.pdf: 11990349 bytes, checksum: 5aa2ee24e8db0a1ccd54b5641e0695b2 (MD5) / CAPES / A síntese de novos compostos de produtos naturais bioativos abre um amplo espectro de possibilidades estratégicas no que se refere a modular ou mesmo descobrir novas propriedades. Triterpenos e esteroides são conhecidos por suas atividades biológicas. A síntese de derivados dessas substâncias propicia a obtenção de novos compostos que podem ser mais ativos do que seus precursores. Este trabalho descreve a síntese de quarenta bromoésteres e α-aminoésteres derivados dos esteroides β-sitosterol e estigmasterol (em mistura 7:3), da substância estigmasteriol, e dos triterpenos α e β amirina (em mistura 1:1), lupeol, ácido ursólico e ácido betulínico, a maioria sendo inédita. Os derivados obtidos foram caracterizados por espectrometria de massas de alta resolução, espectroscopia na região do de infravermelho, espectroscopia de ressonância magnética nuclear de 1H e 13C. Também foram efetuadas medidas de ponto de fusão e [α]D. Os derivados serão submetidos a teste de atividade anti-HIV, atividade anti-proliferativa frente a determinadas linhagens de células tumorais e teste de atividade tripanocida. / The synthesis of new compounds from bioactivity natural products opens a large spectrum of strategic possibilities in terms of modulating or even thought find new properties. Triterpenes and steroids are known for their biological activities. The synthesis provides derivatives of these substances to obtain new compounds which may be more active than their precursors. This work describes the synthesis and forty bromoésteres α-amino esters derivatives of steroids -sitosterol and stigmasterol (7:3 in mixture) of estigmasteriol substance, of triterpenes α and β amyrin (1:1 in mixture), lupeol, ursolic acid and betulinic acid, the most being unprecedented. The derivatives were characterized by spectrometry of high resolution mass spectroscopy, infrared spectroscopy, nuclear magnetic resonance of 1H and 13 C. They were also performed melting point measurements and [α]D. The derivatives will submitted to anti-HIV activity test, anti-proliferative activity against certain cancer cell lines and trypanocide activity test.
17

Změny v metabolismu lipidů u akutních stavů / Changes in Lipid metabolism in acute diseases

Hrabovský, Vladimír January 2014 (has links)
Changes in lipid metabolism in acute diseases. Introduction. Abnormalities in lipid metabolism have been described in critically ill patients repeatedly. While triglycerides behave unpredictably, decrease of cholesterol levels is a typical finding. Further, low levels of cholesterol in critically ill patients have been found to be associated not only with poor prognosis but also increased mortality. Cholesterol is derived in two ways: via de novo synthesis and via dietary absorption. Both the modalities can be monitored by the determination of CH synthesis markers (lathosterol, squalene in blood plasma), and cholesterol absorption markers (sitosterol and campesterol in blood plasma) Material and method: In the first project sixty patients with acute internal disease were involved and their lipid profile was evaluated. Second and third projects have solved the same problem in the group of patients with active Cohn's disease (n=24) and acute upper gastrointestinal bleeding (n=24). Serum concentrations of total, LDL and HDL cholesterol and triglycerides were measured in an enzymatic automated system. Non-cholesterol sterols (lathosterol, squalene, sitosterol, campesterol) were analysed using gas chromatography - mass spektrometry. The data were statistically analysed by the statistical software Sigma Stat 3,1....
18

Optimalizace extrakce bioaktivních látek z bylin do různých druhů méně známých olejových základů / Optimalization of the extraction of bioactive compounds from herbs into different kind of oil bases

Chytil, Dalibor January 2020 (has links)
This diploma thesis deals with the optimization of processes for extraction of bioactive lipophilic compounds from fruits of sea buckthorn (Hippophae Rhamnoides) into various types of plant oil bases using simple maceration. The theoretical part of this thesis deals with the characterization of this herb, its botanical classification, traditional use, chemical composition and medicinal effects. Increased attention is also paid to the characterization of individual types of plant oils used, namely camellia, camellia organic, passionflower, kukui and kiwi oil. The experimental part of the thesis deals with application of theoretical knowledge. The profile of total and free fatty acids for individual plant oil bases was determined by GC/FID, furthet the basic fat numbers were also determined. When optimizing the extraction, emphasis was placed not only on the effect of the extraction agent used, but also on the extraction time (1, 3, 5, 7, 10, 14, 21 and 66 days). The macerates were continuously subjected to the determination of selected parameters (total amount of carotenoids, total amount of phytosterols, lutein, neoxanthin, astaxanthin, stigmasterol, -sitosterol and vitamin E) using UV-VIS spectroscopy and HPLC/PDA. Likewise, the peroxide number was monitored during maceration to assess the degree of oxidative degradation of macerates. The recovery of selected total parameters in individual oils did not differ significantly in most cases. On the contrary, the yield of individual monitored parameters differed significantly. At the same time, static maceration under our conditions was not very suitable for the extraction of vitamin E, stigmasterol and total phytosterols.

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