No description available.

Thesis (Ph.D.)--Cornell University, 2000. / Adviser: Eloy Rodriguez. Includes bibliographical references.

Thesis (Ph.D.) - University of Queensland, 2004. / Includes bibliography.

No description available.

No description available.

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.

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...

A study of hypersensitivity of high school students to the oleoresins of fifty common North Texas plants.

O objetivo do presente estudo foi avaliar os efeitos tóxicos da Senna occidentalis (So) sobre o sistema linfo-hematopoiético em ratos recém-desmamados ou expostos pré-natalmente. Avaliou-se nestes animais: o consumo de água e ração, o ganho de peso; parâmetros hematológicos, padrões histopatológicos, além da resposta imunológica específica e não específica. Inicialmente, o estudo foi realizado em ratos recém-desmamados, os quais foram expostos a diferentes concentrações de sementes de So na ração a saber: 1% (So1), 2% (So2) e 4% (So4) durante 14 dias ou que receberam So4 durante 28 dias. Os animais do grupo peer-feeding (PF) receberam a mesma quantidade de ração consumida pelos animais expostos a So4, porém isentas da planta. Após 14 dias de exposição, os resultados obtidos mostraram uma diminuição significante nos parâmetros de consumo de ração, de ganho de peso e da celularidade da medula óssea e do peso relativo no timo nos grupos So2 e So4 e um aumento no peso relativo do baço nos grupos So2 e So4. Entretanto, os animais dos grupos So4 e PF também apresentaram diminuição da celularidade da medula óssea. Na avaliação da resposta imune não especifica todos grupos expostos às sementes da planta, bem como o grupo PF, apresentaram redução na porcentagem de fagocitose por neutrófilos; porém, apenas o grupo So4 mostrou redução do burst basal por neutrófilos. O estudo morfológico do baço mostrou proliferação hematopoiética extramedular e aumento de megacariócitos multinucleados nos ratos do grupo So4. Apenas nos experimentos com animais do grupo So4 expostos por 28 dias, verificou-se similaridade entre resultados dos parâmetros acima descritos, além da ocorrência de anemia microcítica e hipocrômica. Num segundo momento avaliou-se as proles de ratas que receberam sementes de S. occidentalis a 4% na ração, do 6º ao 20º dia de gestação, assim como as proles das ratas do grupo peer-feeding (PF). Os filhotes provenientes de mães do grupo So4 e PF apresentaram um aumento do burst oxidativo e da fagocitose por neutrófilos. Os animais da prole do grupo PF apresentaram hemograma indicativo de anemia megaloblástica. Já no estudo morfológico do baço verificou-se hematopoiese extramedular nos filhotes das mães do grupo So4. Portanto, a presente pesquisa mostrou que a S. occidentalis pode comprometer alguns parâmetros do sistema imunológico de ratos expostos às sementes da planta durantes diferentes fases do desenvolvimento. Além disso, verificou-se que as sementes desta planta também promovem efeitos tóxicos sobre eritrócitos. A inclusão do grupo PF permitiu verificar que os efeitos observados não são decorrentes de possíveis alterações nutricionais promovidas pela redução do consumo de ração, mas sim relacionados ao efeito tóxico direto da S. occidentalis. / The aim of present study was to determinate the Senna occidentalis (So) toxic effects on lymphohematopoetic system in rats during the growth and pre-natal period. The effects were evaluated on the basis of food consumption, weight gain, hematological and immunological parameters, as well as histopathology analysis. Initially, the study was done in growing rats exposed to S. occidentalis seeds in different concentrations: 1% (So1), 2% (So2) and 4% (So4) in feed during 14 or 28 days. Peer feeding-group of rats (PF) was also evaluated; this group received the same amount of feed of those from So4-group, however, free of S. occidentalis seeds. S. occidentalis 14 days exposure decreased food consumption, weight gain, thymus relative organ weight and bone marrow cellularity and increased the spleen relative weight of rats from So2 and So4-group. However, So4- and PF- groups also presented a decreased bone marrow cellularity. All seed exposed-groups and also PF-group had a decrease on neutrophil phagocytosis percentage; however, only rats from So4-group had a decreased neutrophil basal burst. Spleen morphologic analysis indicated the presence of extramedular hematopoietic proliferation and increased multinucleated megakariocytes on So4-group. Similar results were found for all the parameters described after S. occidentalis exposure during 28 days. Furthermore, the rats of So-4 group presented microcytic and hypochromic anemia. On a second moment, rats offspring exposed to S. occidentalis at 4% in feed during the 6th to 20th gestational day and rats offspring of PF group were evaluated. The So4- and PF- rats offspring groups presented an increased neutrophil oxidative burst and phagocytosis, however PF-rats offspring group also had an altered complete blood count compatible with megaloblastic anemia. Moreover spleen morphologic analysis indicated the presence of extramedular hematopoiesis on So4 rats offspring group. Therefore, the present study showed that S. occidentalis can compromise some immunological parameters in rats exposed to seeds during different development periods. This exposure also promotes toxic effects on erythrocytes. The PF group allowed us to verify that the observed effects are related to direct S. occidentalis toxic effects and not due a possible nutritional alteration caused by the reduced feed ingestion.

Tanto no Brasil como em vários outros países, a Senna occidentalis é uma planta de interesse agropecuário, pois é encontrada em pastos ou como contaminante de cereais, podendo, causar intoxicação na criação animal. Além disto, vem sendo utilizada, empiricamente, na Medicina Humana, para o tratamento de várias afecções. Em estudo recente, verificou-se que frangos tratados com sementes de S. occidentalis apresentavam, além das lesões musculares, alterações em órgãos linfóides. Assim, o presente trabalho procurou verificar se as sementes de S. occidentalis poderiam produzir efeitos tóxicos nos órgãos linfóides de mamíferos, utilizando, para tal, ratos como modelo experimental. As sementes de S. occidentalis foram administradas, durante 14 dias, a ratos Wistar (150-200g), em diferentes concentrações de sementes desta planta na ração: 1% (So1), 2% (So2) e 4%(So4). Os animais do grupo peer-feeding (PF) receberam a mesma quantidade de ração consumida pelos animais tratados com So4, porém isentas da planta. Foram avaliados os seguintes parâmetros: consumo de água e ração e ganho de peso, avaliação hematológica e bioquímica, além da histopatologia, morfometria e de ensaios preconizados para o estudo da resposta imunológica não específica. Todos os ratos pertencentes aos diferentes grupos experimentais apresentaram diminuição no consumo de ração e água e no ganho de peso. A avaliação hematológica revelou anemia microcítica e hipocrômica nos animais que receberam 4% da planta. Além disso, todos os animais dos grupos So2 e So4 apresentaram depleção de células linfóides e redução da polpa branca do baço. Os ratos pertencentes ao grupo So4 apresentaram redução significante no peso relativo do timo e diminuição significante na região cortical e também no diâmetro dos folículos medulares deste órgão. Estes mesmos animais apresentaram diminuição da produção de água oxigenada e óxido nítrico. Em relação à resposta inflamatória, todos os animais dos grupos experimentais, apresentaram redução na evolução do edema inflamatório agudo e crônico. Assim, a presente pesquisa mostrou que, também em mamíferos, a S. occidentalis pode comprometer o sistema imunológico, haja vista as alterações encontradas no timo e baço dos ratos expostos à planta. Além disso, verificou-se que as sementes desta planta também promovem efeitos tóxicos sobre eritrócitos e alterações na resposta inflamatória. A inclusão do grupo PF permitiu verificar que os efeitos aqui encontrados não são devidos a possíveis alterações nutricionais promovidas pela queda do consumo de alimento e sim relacionados ao efeito tóxico direto da S. occidentalis. / Senna occidentalis is a weed which grows in pasture along fences and fields cultivated with cereals as corn and soybean and many reports have been showing intoxication with this plant in different animal species. The effects of daily administration of S. occidentalis seeds in different concentrations 1% (So1), 2 % (So2) and 4% (So4) in ration was investigated in rats. It was also evaluated the effects of rats that received the same amount of ration to those of So4-group, however free of S. occidentalis seeds, (PF-rats). The experimental period lasted 14 days and the effects were evaluated on the basis of food consumption, weight gain, hematological and biochemical parameters, inflammatory and immunological responses, as well as histopathology, relative organ weight and morphometric analysis. All experimental animals, showed significant decrease in ration and water consumption and body weight gain. The hematological parameters revealed microcytic and hypochromic anemia in those animals treated with the higher concentration S. occidentalis seeds. Morphometric analysis of the spleen from So2 and So4-animals displayed a significant decrease in the cortical thickness. The thymus from So4-rats showed reduction in the organ size, and the morphometry revealed thickness and reduction of the diameter of the follicles at the cortical area. The same animals presented reduction in hydrogen peroxide and nitric oxide production. In inflammatory response all experimental animals, showed significant decrease in the evolution of acute and chronic edema. These results showed that the alterations found in this present study are related to the poisonous effects of the S. occidentalis and not to the malnutrition.