This thesis is concerned with the formation and structure of silicified deposits in biology. The major system studied is silicified macrohairs from the lemma of the grass Phalaris canariensis L. The macrohairs consist of silica and polysaccharides. Chemical and structural studies on the mineral phase utilised electron microscopy (transmission (TEM), scanning (SEM) and ultra high resolution (HRTEM)), energy disoersive X-ray analysis (EDXA), solid state nuclear magnetic resonance ( ᷣ⁹ Si nmr), infrared spectroscopy, birefringence and nitrogen adsorption experiments. Results showed that the silica is chemically 'pure', hydrated, amorphous at a resolution of 1OÅ and a variety of structural morphologies were observed which are related to the maturity of the macrohair. Analytical studies at different times after emergence of the inflorescence utilising EDXA and scanning proton microprob eanalysis (SPM) showed that the inorganic elements Si, K, P, S and Cl are spatially organised within the macrohairs during silicification. It is proposed that the macrohairs are silicified under strict cellular control. The organic matrix in the mature macrohairs was investigated by acid hydrolysis and chromatography. The changing emphasis of polysaccharide synthesis in the macrohairs as mineralisation occurs was followed by in vivo radioactive labelling of inflorescences at different stages using ⁱ⁴C glucose and Harabinose. Analysis o fpolysaccharides synthesised involved acid hydrolysis and enzymic digestions (Amylase and Driselase), followed by paper and thin layer chromatography with scintillation counting of the products. Results showed that at the early stages of mineralisation, arabinoxylans and cellulose are the major polymers synthesised but as the macrohair matures, largely non-cellulosic glucans (as yet unidentified) are synthesised. It is proposed that the change in emphasis of polysaccharide synthesis during wall development is related to the size and ultrastructural arrangements of silica particles observed. The organic matrix was also observed to give additional order to the system, the resulting material being totally impervious. A second system, chosen for comparison, is mineralised teeth from the radula of the common limpet Patella vulgata. The mature teeth contain silica, iron oxide (goethite) and an organic matrix. Investigations on the silicified phase utilising electron microscopy revealed morphological structural variations. Analytical studies involving EDXA and SPM analysis showed that there are complex temporal and spatial variations in the inorganic composition (P, S, Ca, Fe, Si, Cu) in all regions of the teeth. It is proposed that these changes can be correlated with changes in composition of the organic matrix. A comparison is made of the silica from the two systems.

Made available in DSpace on 2015-07-22T20:50:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação Oswaldo Ramos (FOR) / Introdução: A hipertensão arterial é uma doença altamente prevalente em todo o mundo e está associada a três doenças crônicas: doença renal, acidente vascular cerebral, e doença cardíaca. Popularmente o alpiste (Phalaris canariensis -Pc) tem sido usado como um agente anti-hipertensivo como adjuvante aos tratamentos convencionais. Os objetivos deste estudo foram avaliar o efeito do extrato aquoso de Pc (EAPc) sobre a pressão arterial e função renal de ratos normotensos e espontaneamente hipertensos (SHR), assim como, avaliar se o tratamento com EAPc seria capaz de impedir o desenvolvimento de hipertensão em SHR ao administrar EAPc após o desmame na fase normotensa. Método: foram utilizados ratos machos adultos Wistar, SHR e SHR jovens normotensos (3 semanas). Os animais foram divididos em grupos controle (recebendo água) e tratados com EAPc (100 mg / kg / dia, v.o.) por 30 dias. Após este período o grupo tratado foi dividido em dois sub-grupos: tratados por mais 30 dias (EAPc 60) e um grupo com tratamento EAPc interrompido, recebendo apenas água durante 30 dias (EAPc 30). A dose do EAPc foi previamente determinada através do efeito agudo de doses crescentes sobre a PAS em ratos cateterizados durante períodos de 6 horas. Resultados: A administração do EAPc por 60 dias propiciou uma redução significante na pressão arterial sistólica (PAS, mmHg) em ambos os grupos de animais adultos, Wistar (122 ± 2 vs 103 ± 4, p <0,05) e SHR (210±1 vs 171±1, p <0,05). No entanto, a interrupção do tratamento foi seguida de um retorno gradual da PAS aos níveis basais em ambos os grupos Wistar (117 ± 1) e SHR (193 ± 3). O grupo SHR jovem normotenso após o desmame (122 ± 2), tornou-se hipertenso após 30 (161 ± 3) e 60 dias (195 ± 4). Entretanto, o tratamento com o EAPc durante 30 e 60 dias minimizou o aumento da PAS (133 ± 2 e 148 ± 4, respectivamente). A interrupção do tratamento causou um aumento na PAS similar ao observado no grupo não tratado. Não houve mudanças significantes nos parâmetros plasmáticos e renais entre os grupos. Conclusão: Os resultados sugerem que o Pc tem potencial efeito anti-hipertensivo em SHR, sem indução de qualquer risco significante de nefrotoxicidade e pode ser uma alternativa e/ou opção de tratamento adjuvante para reduzir a pressão arterial. O mecanismo antihipertensivo do Pc pode estar relacionado à ação vascular, uma vez que não houve modificações significativas na excreção urinária de sódio e água. Entre os constituintes do Pc com potencial ação vasodilatadora destacam-se o triptofano e os ácidos graxos poliinsaturados precursores de quinurenina e ácido aracdônico respectivamente. / Hypertension is a disease highly prevalent throughout the world and it is associated with three chronic diseases namely; stroke, kidney disease, and heart disease. Popularly the birdseed Phalaris canariensis (Pc) has been used as an antihypertensive agent. The aim of this study was to evaluate the effect of the aqueous extract of Pc (AEPc) on arterial pressure and renal function of normotensive Wistar rats and spontaneously hypertensive rats (SHR). Also it was evaluated whether AEPc treatment would be able to prevent the development of hypertension in SHR, by administrating AEPc soon after weaning, i.e. before the establishment of hypertension. Methods: Adult male Wistar rats, SHR and young (3 weeks old) SHR were used. Adult animals were divided into groups control (receiving water) and treated with AEPc (100 mg/kg/day, p.o.) for 30 days. After this period treated group was divided into 2 sub-groups: treated for another 30 days (AEPc 60) and a group which AEPc treatment was interrupted and animals received only water for 30 days (AEPc 30). Young (three weeks old) and nonhypertensive SHR, received AEPc treatment during 30 days. Results: The administration of the AEPc for 60 days produced significant reduction in mean arterial pressure (MAP, mmHg) in both adult groups, Wistar (122±2 vs 103±4, p<0.05) and SHR (210±1 vs 171±, p<0.05). However, the interruption of treatment was followed by a gradual return of MAP to the baseline levels in both groups Wistar (117±1) and SHR (193±3). Young SHR group was normotensive after weaning (122±2) but became hypertensive after 30 (161±3) and 60 days (195±4). AEPc treatment during 30 and 60 days minimized the increase in MAP (133±2 and 148±4, respectively). The discontinuation of the treatment caused an increase in the MAP similar to observed in untreated group. There was no significant change in plasma parameters among groups. Fractional excretion of Na+ (FENa+) was lower in untreated SHR and AEPc treatment restored FENa+ to control levels. Conclusion: The results suggest that Pc has potential antihypertensive effect in SHR, without inducing any significant risk of nephrotoxicity and it may be use as an alternative and/or adjuvant treatment option to reduce blood pressure. The antihypertensive mechanism may be related by action of the biochemical constituents of Pc, mainly tryptophan and linoleic acid, precursors of the vasodilator aguds Kynurenine and prostaglandings respectively. / CAPES: 1326/08 / TEDE / BV UNIFESP: Teses e dissertações

Orientadores: Marcelo Alexandre Prado, Débora Barbosa Vendramini Costa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-27T19:08:56Z (GMT). No. of bitstreams: 1 Oliveira_MicheleChristineMachadode_M.pdf: 3902978 bytes, checksum: 4d585a98c3af2e67dbde235b37799309 (MD5) Previous issue date: 2015 / Resumo: Estudos envolvendo compostos antioxidantes presentes em alimentos e a prevenção ou controle de algumas doenças não transmissíveis têm chamado a atenção da comunidade científica e da população em geral, considerando que esses estudos abrem novas possibilidades para a descoberta de novas substâncias bioativas. Entre os alimentos que contém antioxidantes naturais, as sementes constituem uma importante fonte de suprimento dietético. Dentre as sementes utilizadas pela população para fins medicinais está o alpiste (Phalaris canariensis L.), tradicionalmente usado como tratamento alternativo para o diabetes, porém são escassos os estudos científicos conduzidos com essa espécie. Dessa forma, o objetivo desse estudo foi avaliar a composição química e a atividade antioxidante e hipoglicemiante do extrato aquoso de alpiste. A composição das sementes e do extrato aquoso foram realizados segundo as normas e metodologias da AOAC e Instituto Adolfo Lutz. Os métodos empregados para a avaliação da atividade antioxidante foram o ABTS (2,2'-azino-bis-3-etilbenzotriasolina- 6-ácido sulfônico), DPPH radical (2,2-difenil-1-picrilhidrazil) e o ORAC (Oxygen Radical Absorbance Capacity). A avaliação da atividade hipoglicemiante foi realizada por meio do modelo de diabetes induzida por estreptozotocina (STZ, dose única de 60 mg/kg, via intraperitoneal) em ratos Wistar machos, que foram aleatoriamente distribuídos em grupos de 10 animais, sendo: sham (animais sadios não-diabético); controle negativo (diabéticos não tratados), tratados com extrato aquoso de alpiste (doses de 250, 500 e 1000 mg/kg, via oral) e não diabéticos tratados com a dose de 1000 mg/kg. Dois protocolos foram realizados: tratamentos por 28 dias e de longa duração por 87 dias. Em ambos protocolos os animais foram monitorados semanalmente quanto a massa corporal, glicemia e consumo de água e ração. No final dos experimentos os órgãos foram removidos e pesados e sangue e urina foram coletados para avaliações bioquímicas, hematológicas, eletrolíticas e histopatológicas, afim de constatar a ação do extrato aquoso de alpiste no diabetes. Os resultados obtidos nas sementes de dois lotes e do extrato aquoso foram respectivamente: umidade e resíduo seco (10,31%; 9,50%; 78,21%), cinzas (6%; 5,30%; 1,74%), proteínas (14,88%; 15,12%; 18,26%), lipídeos (5,38%; 5,17%; 2,07%), amido (50,54g/100g; 48,04g/100g; 3,79g/100g) e fibras totais (18,88g/100g; 17,29g/100g; 0,70g/100g). Os ácidos graxos encontrados predominantes foram: ácido palmítico (12%) e poli-insaturados: linoleico (53%), oleico (28%) e linolênico (3%). Compostos fenólicos totais (280,15 ± 3,05 µg EAG/g) e Atividade Antioxidante: ABTS (228,93 ± 2,25µg eqtrolox/g), DPPH (106,17 ± 6,69 µg eqtrolox/g) e ORAC (1177,37 ± 5,32 µM/g na fração hidro e 147,79 ± 0,48 µM/g na lipo). O alpiste e seu extrato mostraram potencial nutritivo, e o extrato apresentou atividade antioxidante intermediária. O tratamento com extrato aquoso de alpiste nas doses experimentais não controlou os níveis glicêmicos, bem como não apresentou efeitos sobre a massa corporal, consumo de água e ração e em nenhum dos parâmetros bioquímicos e hematológicos avaliados, evidenciando que este extrato não apresenta efeitos antiabetogênicos / Abstract: Studies concerning the application of antioxidant compounds from food in the prevention or control of non-transmissible diseases attracted attention of the scientific community and population in general, as theses studies open new possibilities for the discovery of new bioactive compounds. Among foods that contain natural antioxidants, the seeds are an important source of dietary supply. Among the seeds used by the population for medicinal purposes is the canary seed (Phalaris canariensis L.), traditionally used as an alternative treatment of diabetes, however there are only few studies concerning the biological actions of this specie. Thus, the aim of this study was to evaluate the chemical composition and the antioxidant and hypoglycemic activities of the aqueous extract from canary seed. The chemical composition of the extract and seeds was performed according to the methodology and standards of AOAC and Adolfo Lutz Institute. The used to evaluate the antioxidant activity were ABTS (2,2'-azino-bis-3-etilbenzotriasolina- 6-ácido sulfônico), DPPH (2,2-diphenyl-1-picrylhydrazyl) and ORAC (Oxygen Radical Absorbance Capacity). For the evaluation of the hypoglycemic activity, the streptozotocin-induced diabetes model was conducted (STZ, single dose of 60 mg/kg, intraperitoneal route) in male Wistar rats, which were randomly divided into groups of 10 animals, such as: sham (healthy animals, non-diabetic), negative control (diabetic, untreated), treated with aqueous extract from canary seeds (250, 500 and 1000 mg/kg, oral route, daily) and non-diabetic treated with 1000 mg/kg of the extract. Two protocols were performed: treatments for 28 days and for 87 days. In both experiments, the animals were weekly monitored for body weight, glycemia and consumption of food and water. In the end of the experiments, organs were removed and weighted and blood and urine were collected for biochemical, electrolytic and histopathological evaluations, in order to evaluate the action of the aqueous extract of canary seeds in diabetes. Results obtained for seeds obtained from two different lots and for the extract were: humidity and dry residue (10.31%; 9.50%; 78.21%), ash (6%; 5.30%; 1.74%), proteins content (14.88%; 15.12%; 18.26%), lipid content (5.38%; 5.17%; 2.07%), starch content (50.54g/100g; 48.04g/100g; 3.79g/100g) and total fibers (18.88g/100g; 17.29g/100g; 0.70g/100g). Fatty acids were predominantly: palmitic acid (12%) and polyunsaturated: linoleic (53%), oleic (28%), linolenic (3%). Total phenolic compounds (280.15 ± 3.05 µg EAG/g) and antioxidant activity: ABTS (228.93 ± 2.25µg eqtrolox/g), DPPH (106.17 ± 6.69 µg eqtrolox/g) and ORAC (1177.37 ± 5.32 µM/g in the hydro fraction and 147.79 ± 0.48 µM/g in the lipidic fraction). In sum, the aqueous extract from canary seeds showed a nutritional potential and presented intermediate antioxidant activity. Treatments with the extract in the experimental doses did not control the glycemic levels, as wells as had no effects in the body weight, consumption of food and water and in any of the biochemical and hematological evaluations, thus evidencing that the aqueous extract from canary seeds does not have antidiabetogenic effects / Mestrado / Ciência de Alimentos / Mestra em Ciência de Alimentos