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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

Autecology of alfombrilla (Drymaria arenarioides)

Sanchez-Muñoz, Alfonso de Jesus, 1949- January 1978 (has links)
No description available.
2

Traditional plant-based fishing in the Americas an ethnobotanical, phytochemical, and pharmacological investigation /

McFerren, Marcus Anthony. January 2000 (has links) (PDF)
Thesis (Ph.D.)--Cornell University, 2000. / Adviser: Eloy Rodriguez. Includes bibliographical references.
3

Cytotoxic effects of pyrrolizidine alkaloids /

Pereira, Tamara Nishanthi. January 2004 (has links) (PDF)
Thesis (Ph.D.) - University of Queensland, 2004. / Includes bibliography.
4

Toxic compounds in cycads.

Nair, Jerald James. January 1990 (has links)
The present-day cycads comprise the diverse, modified, remnants of a much larger group of gymnosperms which flourished in the Mezozoic era. The systematic position that the cycads occupy in the botanical hierarchy is significant in that they represent relatively unchanged survivors from prehistory. The present global complement of 182 species occur in tropical and mild temperate regions in both hemispheres. Despite the density of proliferation of species, about one-half of the extant taxa are considered endangered, vulnerable or rare. Apart from characteristic features such as differences in growth forms, variation in reproductive structures and anatomical details, cycads are distinguished from all other plant groups by the unique phytotoxins, azoxyglycosides, which they possess. The toxicity of cycads is well-documented in cases which refer to both man and animals. Cycasin, which together with macrozamin represent the major azoxyglycosides occurring in cycads, has been reported to elicit responses similar to those that have been observed during carcinogenicity, mutagenicity and neurotoxicity assays. It has become apparent that the mechanism by which azoxyglycosides manifest their toxicity involves deglucosylation, by enzyme systems, which releases the aglycone, methylazoxymethanol (MAM), and sugar moieties. Metabolic activation of MAM succeeds deglucosylation to generate methylene carbene units (: CH2) which are capable of methylating macromolecules including DNA, RNA and protein. During this investigation, macrozamin was extracted from seed kernels of Encephalartos transvenosus and cycasin was tentatively identified in seed kernels of Cycas thouarsii . The hexa-acetate derivative of macrozamin was prepared whereas the tetra-acetate derivative of cycasin was not secured in a pure form. The spectroscopic techniques employed for identification include DV-absorption, infra-red and nuclear magnetic resonance spectroscopy, all of which are useful for detecting signals which arise as a result of the azoxy function. A kinetic study was carried out to determine the rate of hydrolysis of macrozamin with 4M sulphuric acid, and to allow calculation of the activation energy for the process. A comparison of the kinetic parameters determined for the above process with those derived for the hydrolysis of cycasin and methylazoxymethanol under similar conditions followed. The rates of hydrolysis increase in the order macrozamin, cycasin, methylazoxymethanol since the molecules contain two, one and zero glycosidic linkages respectively. Additional glycosidic bonds are observed to decrease the rate of reaction. Consequently, activation energies for hydrolysis of the above molecules decrease in the above-stated order. Macrozamin and cycasin were quantified in cycad material by high performance liquid chromatography (HPLC), gas-liquid chromatography (GLC) and by the chromotropic acid assay. The results of the quantitative analysis has highlighted certain limitations of the methods of detection, and has been found to be applicable to a taxonomic evaluation and a proposal for the biosynthesis of the azoxyglycosides. / Thesis (M.Sc.)-University of Natal, Durban, 1990.
5

Chemical analysis of medicinal and poisonous plants of forensic importance in South Africa

Steenkamp, P.A. 13 October 2014 (has links)
Ph.D. (Chemistry) / The Forensic Chemistry Laboratory of Johannesburg (FCL JHB) is tasked with the chemical analysis of a variety of samples to assist in determining the cause of death where unnatural cause is suspected. Some of the samples submitted to the laboratory have a herbal or muti connotation, but a large portion of these cases turn out to have no herbal components present as only pharmaceutical or agricultural products are detected in these samples. This study combined, for the first time, forensic investigation, chemistry and botany to create a unique platform needed for the identification of poisonous plants and their components in forensic exhibits and viscera. The research was focussed on the poisonous plants previously detected at the laboratory, as well as the requests received for the analysis of muti/toxic plant components. The selection of plants included Nicotiana glauca, Datura stramonium / Datura ferox, Callilepis laureola, Boophone disticha / Ammocharis coranica, Abrus precatorius, Ricinus communis, Nerium oleander / Thevetia peruviana and Bowiea volubilis. All these species are known to have caused fatalities, hence their choice. Nicotiana glauca has been implicated in the deaths of at least 15 people since 2001. It was previously detected by GC-MS (EI) in plant exhibits, but could not be detected in a viscera matrix. A selective extraction method for alkaloids was used to extract botanical and viscera samples. Anabasine was successfully detected on the HPLC-MS (EI) system but this detection technique was not considered sensitive enough. A very sensitive HPLC-MS method was developed on the ZMD detector by using electrospray technology. This method outperformed both electron impact detectors (GC and HPLC) and could detect 1ng/ml anabasine with relative ease in full scan mode. Datura stramonium and D. ferox have not been previously positively linked to any human poisoning or death due to exposure to botanically derived products at the FCL JHB. Atropine and scopolamine were successfully ionised in ESI positive mode and could be detected at 10 pg/ml and 100 pg/ml level respectively. The identities of the compounds were confirmed by characteristic ISCID fragmentation patterns. The developed method was successfully applied to a suspected heart attack case. The results proved conclusively that the deceased was given D. ferox seeds as part of his meal and an overdose of atropine and scopolamine contributed to his death...
6

Plant Dermatitis: Hypersensitivity to the Oleoresins of Fifty Common North Texas Plants.

Wells, Leora Joanna 08 1900 (has links)
A study of hypersensitivity of high school students to the oleoresins of fifty common North Texas plants.
7

Chemical analysis of medicinal and poisonous plants of forensic importance in South Africa.

Steenkamp, P.A. January 2005 (has links)
The Forensic Chemistry Laboratory of Johannesburg (FCL JHB) is tasked with the chemical analysis of a variety of samples to assist in determining the cause of death where unnatural cause is suspected. Some of the samples submitted to the laboratory have a herbal or muti connotation, but a large portion of these cases turn out to have no herbal components present as only pharmaceutical or agricultural products are detected in these samples. This study combined, for the first time, forensic investigation, chemistry and botany to create a unique platform needed for the identification of poisonous plants and their components in forensic exhibits and viscera. The research was focussed on the poisonous plants previously detected at the laboratory, as well as the requests received for the analysis of muti/toxic plant components. The selection of plants included Nicotiana glauca, Datura stramonium / Datura ferox, Callilepis laureola, Boophone disticha / Ammocharis coranica, Abrus precatorius, Ricinus communis, Nerium oleander / Thevetia peruviana and Bowiea volubilis. All these species are known to have caused fatalities, hence their choice. Nicotiana glauca has been implicated in the deaths of at least 15 people since 2001. It was previously detected by GC-MS (EI) in plant exhibits, but could not be detected in a viscera matrix. A selective extraction method for alkaloids was used to extract botanical and viscera samples. Anabasine was successfully detected on the HPLC-MS (EI) system but this detection technique was not considered sensitive enough. A very sensitive HPLC-MS method was developed on the ZMD detector by using electrospray technology. This method outperformed both electron impact detectors (GC and HPLC) and could detect 1ng/ml anabasine with relative ease in full scan mode. Datura stramonium and D. ferox have not been previously positively linked to any human poisoning or death due to exposure to botanically derived products at the FCL JHB. Atropine and scopolamine were successfully ionised in ESI positive mode and could be detected at 10 pg/ml and 100 pg/ml level respectively. The identities of the compounds were confirmed by characteristic ISCID fragmentation patterns. The developed method was successfully applied to a suspected heart attack case. The results proved conclusively that the deceased was given D. ferox seeds as part of his meal and an overdose of atropine and scopolamine contributed to his death. Callilepis laureola is reputed to be one of the more commonly used medicinal plants in South Africa, and although its use has been indicated by the specific mention of a possible nephrotoxin and/or hepatotoxin as causative agent, it has not been detected in any of the forensic chemistry laboratories in South Africa. This was mainly due to the absence of a reliable method for the analysis of the main toxic component of C. laureola, atractyloside, by mass spectrometry. A sensitive and very selective HPLC-ESI-MS method was developed that could detect atractyloside, carboxyatractyloside and their monodesulfated analogues in botanical and viscera matrices. The method was successfully applied to a variety of forensic samples and proved that C. laureola may play an important role in herbal poisonings. In a selection of suspected herbal poisonings where the cause of poisoning was unknown, 30% of the samples tested positive for the presence of atractyloside, carboxyatractyloside or their monodesulfated analogues. The bulbs of Boophone disticha are rich in isoquinoline alkaloids and some of the alkaloids were detected by GC-EI-MS and LC-EI-MS, but the detection of these alkaloids in viscera samples was not successful. A routine method used for the screening for drugs of abuse in forensic samples, were successfully used for the analysis of the bulb extracts of B. disticha and the bulb scales of A. coranica. The chromatographic profile of these two plants appeared very similar at a first glance, but a closer evaluation of the mass spectra highlighted significant differences between the two plants. Six alkaloids from B. disticha were isolated and characterised by LC-MS and NMR and these compounds were detected in suspected herbal poisoning cases. It has been shown that B. disticha is one of the commonly used plants to “clean the system” but frequently results in the death of the patient. Abrus precatorius contains one of the most toxic compounds known to mankind, namely abrin that collectively refers to a group of glycoproteins. The seeds of A. precatorius also contain two indole alkaloids, abrine and hypaphorine. The two alkaloids were fractionated and characterised by LC-MS and NMR. Due to the fact that the instrumentation of the FCL JHB is not suited to the detection of proteins, an LC-ESI-MS method was developed for the detection of the two alkaloids in plant and viscera matrix as markers for A. precatorius. The presence of these two alkaloids was indicated on the TMD system (EI spectra) in a suspected herbal poisoning case. The LC-ESI-MS method was applied to the analysis of the samples and the absence of abrine and hypaphorine were proven in the samples. Ricinus communis is similar to A. precatorius in that it also contains a group of extremely poisonous glycoproteins, collectively refered to as ricin. The analysis of R. communis seeds encountered the same problems as the analysis of A. precatorius seeds, and the analysis was again focused on the detection of the minor piperidine alkaloid ricinine. The LC-ESI-MS method developed for abrine was modified to detect ricinine and functioned well in botanical and viscera matrices. This method will enable the forensic analyst to detect ricinine in very low levels when the presence of ricinoleic acid in samples indicates the use of a R. communis-based product. Nerium oleander is a common decorative garden plant that is used medicinally. The plant is rich in cardenolides with oleandrin the main compound. A reversed-phase chromatographic method with ESI mass spectral detection was developed to separate and detect 11 cardiac glycosides. The compounds were adequately separated to allow unambiguous identification, and displayed very stable cationisation with sodium. An extraction method was developed to extract the cardiac glycosides from the leaves of N. oleander and Thevetia peruviana and was also evaluated in a viscera matrix. The extraction method functioned well and extracted a variety of compounds that produced unique chromatographic fingerprints, allowing for the easy differentiation between the two plants. The method is ideally suited for the detection of oleandrin in high concentrations (full scan mode), low concentrations (selected masses) or trace levels (SIM analysis of ion clusters). The method is able to distinguish between extracts derived from N. oleander and T. peruviana and was able to detect and confirm neriifolin, odoroside and neritaloside in N. oleander leaf extracts. Analysis of forensic case exhibits were also successfully done with this method and performed well with liquid and solid matrices. With the new method oleandrin could be detected at trace levels in viscera samples that did not produce positive results in the past. Bowiea volubilis is widely used as a medicinal plant, but is also an extremely toxic plant. It is freely available at traditional healer markets, and is one of the most highly traded plants on the Durban market. Despite the high usage of the plant, it has not been detected by any of the forensic laboratories in South Africa. Bovoside A, a bufadienolide, is reported to be the main cardiac glycoside in the bulb of B. volubilis. The cardiac glycoside method was successfully applied to the analysis of the bulb extract of B. volubilis and bovoside A was identified as the main bufadienolide present in the bulb. Bovoside A was fractionated and characterised by LC-MS. Four extracts of botanical origin could be successfully distinguished from each other by monitoring the main masses of bovoside A, oleandrin and thevetin A and thevetin B. These marker compounds were well separated from each other and made the identification of the botanical extracts quite easy, and the identity of each extract was confirmed by the mass spectrum of each peak. / Prof. F.R van Heerden
8

Efeitos de lantadenos sobre a bioenergética em mitocôndrias isoladas de fígado de rato /

Garcia, Andréa Fontes. January 2009 (has links)
Orientador: Fábio Erminio Mingatto / Banca: Daniel Junqueira Dorta / Banca: Sérgio Diniz Garcia / Resumo: Lantana camara (Verbenaceae) é uma importante planta daninha tropical que causa hepatotoxicidade tanto em ruminantes como em humanos. A maioria dos compostos isolados das folhas da lantana são triterpenóides pentacíclicos conhecidos como lantadenos, sendo o mais abundante o lantadeno A (LA). As mitocôndrias desempenham uma função crucial na manutenção dos processos celulares dependentes de ATP. Neste trabalho foi avaliada a ação do LA e do seu metabólito reduzido (RLA) na bioenergética estudando os seus efeitos na respiração, potencial de membrana e níveis de ATP em mitocôndrias isoladas de fígado de rato energizadas com succinato. Na faixa de concentração testada (5-25 µM), RLA estimulou a respiração de estado 4 e inibiu a de estado 3, estimulou a respiração de estado 3 inibida pela oligomicina, dissipou o potencial de membrana e diminuiu os níveis de ATP de uma forma dose-dependente. Entretanto, LA não estimulou a respiração de estado 4, nem afetou os outros parâmetros mitocondriais na mesma extensão que o RLA. Os lantadenos não inibiram a respiração desacoplada por CCCP, mas estimularam a atividade da ATPase em mitocôndrias intactas acopladas. A atividade da ATPase em mitocôndrias intactas desacopladas ou rompidas não foi afetada pelos compostos. Portanto, RLA age como um desacoplador da fosforilação oxidativa e o LA age em outros componentes da membrana mitocondrial que não a ATP sintase afetando a bioenergética mitocondrial. Esses efeitos podem contribuir para a hepatotoxicidade da lantana. / Abstract: Lantana camara (Verbenaceae) is an important tropical weed that causes hepatotoxicity even in ruminant or in human. The principal isolated compounds of lantana are the pentacyclic triterpenoids known as lantadenes, being the lantadene A (LA) the most abundant. Mitochondria are key to the maintenance of many cellular functions dependent of ATP. This work addressed the action of LA and its reduced derivative (RLA) on mitochondrial bioenergetics by assessing their effects on respiration, membrane potential and ATP levels in succinate-energized isolated rat liver mitochondria. At the concentration range tested (5-25 µM), RLA stimulated state-4 respiration, inhibited state-3 respiration, circumvented oligomycin-inhibited state-3 respiration, dissipated membrane potential and depleted ATP in a dose-dependent manner. However, LA did not stimulate state-4 respiration, nor did it affect the other mitochondrial parameters to the extent of its reduced derivative. The lantadenes didn't inhibit the CCCP-uncoupled respiration but increased the ATPase activity of intact coupled mitochondria. The ATPase activity of intact uncoupled or disrupted mitochondria was not affected by the compounds. Therefore, RLA acts as a mitochondrial uncoupler of oxidative phosphorylation and LA acts in other mitochondrial membrane components rather than the ATP synthase affecting the mitochondrial bioenergetics. Such effects may account for the hepatoxicity of lantana. / Mestre
9

Efeitos de lantadenos sobre a bioenergética em mitocôndrias isoladas de fígado de rato

Garcia, Andréa Fontes [UNESP] 15 December 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:25:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-15Bitstream added on 2014-06-13T18:29:08Z : No. of bitstreams: 1 garcia_af_me_araca.pdf: 1332928 bytes, checksum: d6b709a9f4bbd3e7b0f6b54781c3026a (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Lantana camara (Verbenaceae) é uma importante planta daninha tropical que causa hepatotoxicidade tanto em ruminantes como em humanos. A maioria dos compostos isolados das folhas da lantana são triterpenóides pentacíclicos conhecidos como lantadenos, sendo o mais abundante o lantadeno A (LA). As mitocôndrias desempenham uma função crucial na manutenção dos processos celulares dependentes de ATP. Neste trabalho foi avaliada a ação do LA e do seu metabólito reduzido (RLA) na bioenergética estudando os seus efeitos na respiração, potencial de membrana e níveis de ATP em mitocôndrias isoladas de fígado de rato energizadas com succinato. Na faixa de concentração testada (5–25 µM), RLA estimulou a respiração de estado 4 e inibiu a de estado 3, estimulou a respiração de estado 3 inibida pela oligomicina, dissipou o potencial de membrana e diminuiu os níveis de ATP de uma forma dose-dependente. Entretanto, LA não estimulou a respiração de estado 4, nem afetou os outros parâmetros mitocondriais na mesma extensão que o RLA. Os lantadenos não inibiram a respiração desacoplada por CCCP, mas estimularam a atividade da ATPase em mitocôndrias intactas acopladas. A atividade da ATPase em mitocôndrias intactas desacopladas ou rompidas não foi afetada pelos compostos. Portanto, RLA age como um desacoplador da fosforilação oxidativa e o LA age em outros componentes da membrana mitocondrial que não a ATP sintase afetando a bioenergética mitocondrial. Esses efeitos podem contribuir para a hepatotoxicidade da lantana. / Lantana camara (Verbenaceae) is an important tropical weed that causes hepatotoxicity even in ruminant or in human. The principal isolated compounds of lantana are the pentacyclic triterpenoids known as lantadenes, being the lantadene A (LA) the most abundant. Mitochondria are key to the maintenance of many cellular functions dependent of ATP. This work addressed the action of LA and its reduced derivative (RLA) on mitochondrial bioenergetics by assessing their effects on respiration, membrane potential and ATP levels in succinate-energized isolated rat liver mitochondria. At the concentration range tested (5–25 µM), RLA stimulated state-4 respiration, inhibited state-3 respiration, circumvented oligomycin-inhibited state-3 respiration, dissipated membrane potential and depleted ATP in a dose-dependent manner. However, LA did not stimulate state-4 respiration, nor did it affect the other mitochondrial parameters to the extent of its reduced derivative. The lantadenes didn’t inhibit the CCCP-uncoupled respiration but increased the ATPase activity of intact coupled mitochondria. The ATPase activity of intact uncoupled or disrupted mitochondria was not affected by the compounds. Therefore, RLA acts as a mitochondrial uncoupler of oxidative phosphorylation and LA acts in other mitochondrial membrane components rather than the ATP synthase affecting the mitochondrial bioenergetics. Such effects may account for the hepatoxicity of lantana.
10

Estudo sobre a toxicidade da Aspidosperma pyrifolium (pereiro) / on the toxicity of Aspidosperma pyrifolium (pereiro)

Lima, Maíra Conceição Jeronimo de Souza 25 February 2011 (has links)
Made available in DSpace on 2016-08-15T20:31:37Z (GMT). No. of bitstreams: 1 MairaCJSL_DISSERT.pdf: 420836 bytes, checksum: 822f4cc895779b5cc7c308d8152a664d (MD5) Previous issue date: 2011-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to evaluate the spontaneous cases of poisoning in goats, rats and toxicity in vitro cytotoxicity of Aspidospema pyrifolium. In all spontaneous cases studied, the plant is ingested and the abortion cases occurred exclusively in goats. Most cases of abortion occurred during the dry season and early rainy season, and experienced the goats were less affected than the young goats. We used male and female rats of Wistar strain. The extract of the plant A. pyrifolium was administered in females at day 15 of gestation or from the 15th to the 17th day of gestation, which showed reduced fetal weight and strong evidence of maternal toxicity. Rats subjected to intraperitoneal injection of the extract of A. pyrifolium showed motor dysfunction and death, male rats were more resistant than females. The administration of atropine, diazepam and xylazine did not help in preventing the effects of toxicity. The evaluation of osmotic fragility of red blood cells was performed with the plant extract in different concentrations. In addition, we used larvae from a day of brine shrimp, which were incubated with different concentrations of the extract. It was found that the extract of A. pyrifolium promoted hemolysis and was lethal to A. saline. These in vitro tests may be useful as adjunct tests for further studies with this plant. / O presente trabalho teve por objetivo avaliar casos espontâneos de intoxicação em caprinos, toxicidade em ratos e citotoxicidade in vitro da Aspidospema pyrifolium. Em todos os casos espontâneos estudados, a ingestão da planta e os casos de aborto ocorreram exclusivamente em caprinos. A maioria dos casos de aborto ocorreu durante a estação seca e início da estação chuvosa, e as cabras experientes eram menos afetadas do que as cabras jovens. Foram utilizados ratos machos e fêmeas da linhagem Wistar. O extrato obtido da planta A. pyrifolium foi administrado nas fêmeas no 15º dia de gestação ou a partir do 15º ao 17º dia de gestação, que apresentaram redução do peso fetal e fortes indícios de toxicidade materna. Ratas submetidas a injeção intraperitoneal do extrato da A. pyrifolium apresentaram distúrbios motores e morte; ratos machos foram mais resistentes do que as fêmeas. A administração de atropina, xilazina e diazepam não auxiliou na prevenção dos efeitos de toxicidade. A avaliação da fragilidade osmótica das células vermelhas do sangue foi realizada com o extrato da planta em diferentes concentrações. Além disso, utilizou-se larva de um dia de Artemia salina, que foram incubadas com diferentes concentrações do extrato. Verificou-se que o extrato de A. pyrifolium promoveu hemólise e foi letal para A. salina. Estes testes in vitro podem ser úteis como testes adjuntos de mais estudos com esta planta.

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