Efeito antioxidante do tucum-do-cerrado [Bactris setosa] em ratos submetidos ao etresse oxidativo induzido por ferro

Tese (doutorado)–Universidade de Brasília, Faculdade de Ciências da Saúde, Departamento de Nutrição, Programa de Pós-graduação em Nutrição Humana, 2013.O bioma Cerrado ocupa grande área do território brasileiro, sendo caracterizado por fatores abióticos extremos, como longos períodos de estiagem, queimadas ocasionais e solos ácidos com presença de metais pesados, os quais o transformaram em um dos mais ricos biomas de savana do mundo, em termos de biodiversidade. Partindo da hipótese que esses fatores abióticos adversos selecionaram espécies resistentes ao estresse, com moléculas bioativas capazes de proteger tais espécies, realizamos um estudo in vitro que objetivou verificar a atividade antioxidante (AA) de partes comestíveis de doze espécies nativas do Cerrado, araticum (Annona crassiflora), baru (Dipteryx alata), cagaita (Eugenia dysenterica), ingá (Inga laurina), jatobá-do-cerrado (Hymenaea stigonocarpa), jenipapo (Genipa americana), jurubeba (Solanuma paniculatum), lobeira (Solanum lycocarpum), mangaba (Hancornia speciosa), tucum-do-cerrado (Bactris setosa); cajuzinho-docerrado (Anacardium humile) e o palmito da guariroba (Syagrus oleracea), em relação à AA da maçã vermelha (Malus domestica), utilizando o ensaio com o radical DPPH•. Entre as doze espécies analisadas, a lobeira, araticum, jurubeba, cagaita, cajuzinho e tucum apresentaram alta AA em relação à maçã. Com objetivo de verificar a AA in vivo do tucum, ratos Wistar (200g), machos, foram tratados por 30 dias com dieta para roedores (AIN-93G), suplementada ou não com ferro (agente estressor), adicionada ou não com 15% de tucum (polpa e casca). Como marcadores do estado em ferro, determinou-se os níveis de ferro sérico, nos tecidos e os níveis dos transcritos das proteínas hepcidina, ferroportina, transportador de metais bivalentes (DMT1). Os níveis teciduais de malondialdeído (MDA), proteína carbonilada, capacidade redutora de ferro no plasma (FRAP) e níveis de transcrito da catalase e do fator nuclear (erythroid-derived-2) like 2 (Nrf2), foram avaliados para determinação do estado oxidativo dos ratos. A suplementação com ferro resultou no aumento significativo dos níveis de ferro no soro, fígado, baço e intestino, no aumento da saturação de transferrina, nos níveis hepáticos de MDA e de transcritos de hepcidina, porém, reduziu os níveis de transcritos da ferroportina no baço. A suplementação com ferro resultou ainda, no aumento da atividade das enzimas Catalase (CAT) e Glutationa S-Transferase (GST) no rim, e da Glutationa Peroxidase (GPx) no intestino, além de aumentar os níveis de transcrito de Nrf2 no intestino e baço. O consumo de tucum reduziu os níveis de transcrito de hepcidina hepática e de ferro intestinal. Além disso, reduziu os níveis de danos oxidativos a proteínas e lipídeos no baço, e aumentou a capacidade redutora de ferro no plasma. O consumo de tucum pelos ratos suplementados com ferro suprimiu a indução da expressão do gene da Nrf2 no baço, o aumento das atividades das enzimas CAT, GST e GPx e a indução do gene da hepcidina induzidos pela suplementaçao com ferro. Além disso, o consumo de tucum aumentou a capacidade redutora no plasma dos ratos suplementados com ferro. Esses resultados sugerem que o tucum tenha compostos antioxidantes e que seu consumo protege os tecidos contra danos oxidativos, aumentando a mobilidade de ferro tecidual, pela inibição da expressão gênica da hepcidina. ______________________________________________________________________________ ABSTRACTThe Cerrado occupies large area of Brazil, characterized by extreme abiotic factors, such as long periods of drought, occasional fires and soils with heavy metals, which have transformed it into one of the richest savanna biomes of the world, in terms of biodiversity. Assuming that these adverse abiotic factors selected stress-resistant species with bioactive molecules that protect these species, we conducted an in vitro study that aimed to determine the antioxidant activity (AA) of edible parts of twelve species native from Cerrado, araticum (Annona crassiflora), baru (Dipteryx alata), cagaita (Eugenia dysenterica), Inga (Inga laurina), jatobá-do-cerrado (Hymenaea stigonocarpa), jenipapo (Genipa americana), jurubeba (Solanuma paniculatum), lobeira (Solanum lycocarpum), mangaba (Hancornia speciosa), tucum-do-cerrado (Bactris setosa); cajuzinho-do-cerrado (Anacardium humile) and the guariroba palm (Syagrus oleracea), in relation to the AA of red apple (Malus domestica), using the DPPH•. Among the twelve species studied, the lobeira, araticum, jurubeba, cagaita, cajuzinho and tucum showed high AA compared to apple. Aiming to evaluate the AA tucum in vivo, male Wistar rats (200g), were treated for 30 days with food for rodents (AIN-93G), supplemented or not with iron (stressor), added or not with 15 % of tucum (pulp and peel). As iron status markers, were determined the levels of serum iron and tissue levels of transcripts of protein hepcidin, ferroportin, divalent metal transporter (DMT1). The level of malondialdehyde (MDA) and carbonyl protein in tissues, iron reduction capacity in plasma (FRAP) and transcript levels of catalase and nuclear factor (erythroidderived- 2) like 2 (Nrf2), were measured to determine the oxidative state of rats. Iron supplementation resulted in a significant increase in the iron levels in serum, liver, spleen and intestine, increase transferrin saturation, hepatic levels of MDA and hepcidin transcripts, but reduced the levels of transcripts ferroportin in spleen. Iron supplementation also resulted in increased activity of the enzymes Catalase (CAT) and Glutathione S-transferase (GST) in the kidney, and Glutathione Peroxidase (GPx) in the intestine, in addition to increasing levels of Nrf2 transcript in the intestine and spleen. The consumption of tucum reduced transcript levels of liver hepcidin and intestinal iron. Furthermore, reduced levels of oxidative damage in lipids and proteins in the spleen, and increased capacity reduction of plasma iron. Tucum consumption by rats supplemented with iron, suppressed the induction of Nrf2 gene expression in spleen, increased activity of the CAT, GST and GPx enzymes, and the induction hepcidin gene induced by iron supplementation. Moreover, consumption of tucum increased ferric reducing ability in the plasma mice of iron supplemented. These results suggest that the tucum has antioxidant compounds and its consumption protects tissues against oxidative damage, increasing mobility of iron tissue by inhibiting the expression of hepcidin gene

Brazilian savanna fruits contain higher bioactive compounds content and higher antioxidant activity relative to the conventional red delicious apple

The bioactive compounds content and the antioxidant activity (AA) of twelve fruits native to the Cerrado were compared with the Red Delicious apple by means of the antiradical efficiency (using the 2,2-diphenyl-1-picrylhydrazil assay/DPPH), ferric reducing antioxidant power (FRAP) and the b-carotene/linoleic system. The antiradical efficiency (AE) and the kinetic parameters (Efficient concentration/EC50 and time needed to reach the steady state to EC50 concentration/TEC50) of the DPPH curve were also evaluated for comparison with the Trolox equivalent (TE) values. A strong, significant and positive correlation was observed between the TE and AE values, whereas a weak and negative correlation was observed between TE and EC50, suggesting that the values of AE and TE are more useful for the determination of antiradical activity in fruits than the widely used EC50. The total phenolic content found in the fruits corresponded positively to their antioxidant activity. The high content of bioactive compounds (flavanols, anthocyanins or vitamin C) relative to the apple values found in araticum, cagaita, cajuzinho, jurubeba, lobeira, magaba and tucum corresponded to the high antioxidant activity of these fruits. Flavanols and anthocyanins may be the main bioactive components in these Cerrado fruits. The daily consumption of at least seven of the twelve Cerrado fruits studied, particularly, araticum, cagaita, lobeira and tucum, may confer protection against oxidative stress, and thus, they may prevent chronic diseases and premature aging. The findings of this study should stimulate demand, consumption and cultivation of Cerrado fruits and result in sustainable development of the region where this biome dominates

Vitamina A no leite materno : influência do estado nutricional de lactantes e da composição do leite

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Biologia Celular, 2008.O leite materno é a única fonte de vitamina A para crianças que são amamentadas de forma exclusiva em seus primeiros meses de vida. Níveis adequados de vitamina A no leite são fundamentais, pois as crianças ao nascerem possuem um estoque hepático baixo desta vitamina. A presença deste nutriente no leite tem sido utilizada como um indicador do estado nutricional desta vitamina em lactantes e lactentes. Alguns fatores maternos podem estar relacionados ao estado nutricional de vitamina A em mulheres que amamentam. O objetivo do presente trabalho foi verificar se fatores ligados a mãe como a ingestão habitual de vitamina A, o índice de massa corporal (IMC), a gordura periférica, a gordura central e alguns compostos do leite, como a gordura, a proteína, o zinco e o ferro, estão associados aos teores de vitamina A presentes no leite. A pesquisa foi realizada em 92 lactantes, entre a terceira e quarta semana pós-parto, que deram a luz no Hospital Regional de Taguatinga e Hospital Universitário de Brasília entre maio de 2004 e novembro de 2005. Foram realizadas medidas antropométricas e dois inquéritos dietéticos de 24 horas. As dosagens de gordura, proteínas totais, zinco, ferro e vitamina A foram feitas nas amostras de leite destas mães. Uma alta porcentagem das lactantes estudadas, 37%, apresentaram estado nutricional deficientes em vitamina A. As análises demonstraram que quando a ingestão habitual desta vitamina era superior a Média de Requerimento Estimada para Grupos (EAR), a dieta influenciava diretamente as concentrações de vitamina A presente no leite (p= 0,05), o que não acontecia quando a ingestão habitual era inferior a EAR (p= 0,41), indicando que vitamina A ingerida supre prioritariamente as necessidades do organismo materno. O IMC mostrou uma tendência a influenciar positivamente nos níveis de vitamina A no leite (p= 0,06), sugerindo que o acúmulo de gordura corporal que ocorre no último trimestre de gestação é importante para a manutenção do estado nutricional de vitamina A da lactante. Fatores como a gordura central e a gordura periférica das mães, proteínas totais e zinco no leite não influenciaram de forma significativa os teores de vitamina A no leite. A vitamina A presente no leite foi fortemente influenciada pelos níveis de gordura encontrados no leite (p< 0,001), o que pode ser conseqüência da lipossolubilidade e do processo de secreção dessa vitamina no mesmo. Constatou-se uma estreita associação entre os níveis de vitamina A e ferro no leite, indicando que a adequação dos níveis de ferro e vitamina A no leite são interdependentes. __________________________________________________________________________________ ABSTRACTThe milk is the only source of vitamin A to children who are only breastfed in its first months of life. Adequate levels of vitamin A in milk are important because children born with low level of it in the liver. The presence of this nutrient in milk has been used as an indicator of nutritional status of this vitamin in infants and mothers. Some factors may be related to mothers' nutritional status of vitamin A in these women who breastfeed. The objective of this work was to check whether factors associated with mother as the habitual intake of vitamin A, the body mass index (BMI), peripheral fat, central fat and some compound of milk, such as fat, protein, zinc and iron, are associated with levels of vitamin A in milk. The research was conducted in 92 breastfeeding mothers, between the third and fourth week after birth at the Regional Hospital of Taguatinga and University of Brasilia Hospital between May 2004 and November 2005. Anthropometric measurements and 24 hours diet recalls were conducted. The fat, protein, zinc, iron and vitamin A levels were taken from the milk samples of mothers. A high number of studied mothers, 37% of them, had poor nutritional status in vitamin A. The analyses showed that when the usual dietary intake of vitamin A was above the Average for the Application Estimated Groups (EAR), the diet has a direct influence the concentrations of vitamin A in milk (p= 0.05). The same did not happen in the case the usual dietary intake was below normal (p= 0.41). This is a sign that vitamin A intake is priority used for the mother's body need. The BMI showed a tendency to influence in a very important manner the levels of vitamin A in milk (p= 0.06). The accumulation of body fat in the last trimester of pregnancy is important for maintaining the nutritional status of vitamin A of in the mother. Some factors such as central fat and peripheral fat, total protein and zinc in the milk did not influence significantly the levels of vitamin A. Vitamin A present in the milk was strongly influenced by levels of fat found in milk (p< 0,001), which may be a consequence of fat solubility and the process of secretion of this vitamin in it. Furthermore, there is a close association between levels of vitamin A and iron in milk. That indicates that the adequacy levels of iron and vitamin A in milk are interdependent

Bioactive compounds (mg/100 g of fresh matter) of apple and twelve fruits native to the Brazilian Cerrado.

<p>Means ± SD (n  =  3) followed by *, **, *** are significantly different from Red Delicious apple values (^* p<0.05; ^** p<0.01; ^*** p< 0.001; T test, independent samples. </p

The free radical scavenging capacity (DPPH) in the EtOAc and aqueous extracts of the fruits expressed as the Trolox equivalent (TE), the concentration of antioxidant required to reduce the original amount of DPPH^⋅ to 50% (EC₅₀), and the antiradical efficiency (AE) estimated by the equation (1/EC₅₀.TEC₅₀) in which TEC₅₀ corresponds to the time of stabilization of EC₅₀ according to Sánchez-Moreno et al. (1998).

<p>Means ± SD (n  =  3) followed by *, **, *** are significantly different from values obtained for apple and followed by #, ##, ### are significantly different from EtOAc extract (^*,# p<0.05; ^**,## p<0.01; ^***,### p<0.001; T test, independent samples.</p

Ferric reducing antioxidant power (FRAP) and inhibition of β-carotene/linoleic oxidation assays.

<p>Means ± SD (n  =  3) followed by *, **, *** are significantly different from apple value; and followed by #, ##, ### are significantly different from EtOAc extract (^*,# p<0.05; ^**,## p<0.01; ^{***, ###} p< 0.001; T test, independent samples).</p