Biodisponibilidade de selênio em feijão (Phaseolus vulgaris L.) e castanha-do-Pará (Bertholletia excelsa H.B.K.) e seu potencial anticarcinogênico na mucosa do cólon de ratos

• Ano de defesa: 2007
• Autor(a) principal: Sales, Nadja Santos de
• Orientador(a): Costa, Neuza Maria Brunoro
• Banca de defesa: Matta, Sérgio Luis Pinto da , Freitas, Renata Nascimento de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Ciência e Tecnologia de Alimentos
• Departamento: Ciência de Alimentos; Tecnologia de Alimentos; Engenharia de Alimentos
• País: BR
• Palavras-chave em Português: Selênio; Biodisponibilidade; Câncer; Feijão; Castanha-do-Pará; Phaseolus vulgaris; Bertholletia excelsa
• Palavras-chave em Inglês: Selenium; Bioavailability; Cancer; Beans; Brazil nut; Phaseolus vulgaris; Bertholletia excelsa
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS
• Link de acesso: http://locus.ufv.br/handle/123456789/511

Selenium (Se) is a trace element with antioxidant property and important enzimatic functions as selenocysteine. The low Se status is positively related with the incidence of chronic diseases, including cancer. Food components of the Brazilian diet, such as Brazil nut, naturally rich in selenium, and beans, with attributed functional properties to some of its constituents as fiber, phytate, and tannins are promising in the reduction of the risk of these chronic diseases. The objective of the current study was to evaluate the bioavailability of Se in 5 bean cultivars (Ouro Branco, Diamante Negro, BRS Radiante, Pérola, and Talismã), and in Pérola beans fertilized with Se. The study also aimed to evaluate the functional potential of black beans and Brazil nut in reducing the risk of colon cancer in rats. In the bioavailability study the bean cultivars were cooked with their soaking water; then, they were dried in oven, milled and analyzed for Se content. Female adult rats received their experimental diets containing the same levels of Se provided by the beans for 28 days. One control group with Se and another control group without Se were also included in the study. The activity of plasma and liver Glutathione Peroxidase (GPx) and the erythrocyte Se were determined. There was no difference between bean cultivars and beans fertilized with Se and its control in terms of Se bioavailability, as measured by liver and plasma GPx activity. To evaluate the anticarcionogenic effect of black beans and Brazil nut on colon cancer, 45 male F344 rats were distributed in 5 groups and fed with hyperlipidic diest for 12 weeks. One group received control AIN-93 diet without Se (CN), another group received AIN-93 diet supplemented with 4 mg Se kg-1 (CP), other two groups were fed the same Se dose of CP diet, provided either by Brazil nut (C) or Brazil nut + beans (F+C) and the last group received diet with beans (F). The carcinogen DMH and its vehicle (control) were administred to the animals in two consecutive doses at weeks two and three after diet introduction. Plasma Se and the activity of liver, erythrocyte and plasma GPx and liver Glutathione S-transferase (GST) were measured. Cell differenciation, cell proliferation and morphological characteristics of cript and colon were biomarkers for the risk of cancer. The diets CP, C, F and F+C promoted the same expression levels of GPx and GST, higher cell differentiation and lower cell proliferation of colon mucosa, in relation to CN diet. No change was observed with DMH administration. Nutritional overdoses of Se provided by SeMet, Brazil nut or their combination with beans (C+F) and the supplied bean separately (F) promoted homeostase of colon development, and avoided changes in cell differentiation and proliferation in DMH-treated rats. This suggests a protective role of these food or its components on colon cancer. The results seem to be due to multiple mechanisms of action.