Kiriaque Barra Ferreira Barbosa

Estresse oxidativo: conceito, implicações e fatores modulatórios

There is evidence that oxidative stress, defined as a persistent imbalance between the production of highly oxidative compounds and antioxidant defenses, leads to tissue damage. Oxygen metabolism generates free radicals and/or non-radical reactive oxygen species. The mitochondria, through the electron transport chain, are the main generator of these species. The antioxidant defense system has the function of inhibiting and/or reducing the damage caused by the deleterious free radicals and/or non-radical reactive oxygen species. This system is divided into enzymatic (superoxide dismutase, catalase and glutathione peroxidase), and nonenzymatic. The nonenzymatic system consists of a variety of antioxidant substances, which may be endogenous or dietary. This study proposed to review the main mechanisms of reactive oxygen species generation and the role of the most relevant agents of the antioxidant defense system on the biomarkers of oxidative stress. The main exogenous factors that modulate oxidative stress will also be discussed.O estresse oxidativo decorre de um desequilibrio entre a geracao de compostos oxidantes e a atuacao dos sistemas de defesa antioxidante. A geracao de radicais livres e/ou especies reativas nao radicais e resultante do metabolismo de oxigenio. A mitocondria, por meio da cadeia transportadora de eletrons, e a principal fonte geradora. O sistema de defesa antioxidante tem a funcao de inibir e/ou reduzir os danos causados pela acao deleteria dos radicais livres e/ou especies reativas nao radicais. Esse sistema, usualmente, e dividido em enzimatico (superoxido dismutase, catalase e glutationa peroxidase) e nao-enzimatico. No ultimo caso, e constituido por grande variedade de substâncias antioxidantes, que podem ter origem endogena ou dietetica. Objetivou-se revisar os principais mecanismos de geracao de radicais livres, bem como a acao dos agentes mais relevantes do sistema de defesa antioxidante, ressaltando suas implicacoes sobre os marcadores do estresse oxidativo. Tambem serao abordados os principais fatores exogenos moduladores do estresse oxidativo.

Mapa de preferência de sorvetes ricos em fibras

Four samples of ice cream were prepared with four different concentrations of granola and fructooligosaccharide (FOS). The concentration of fiber was evaluated using the AOAC method. The acceptance evaluation was conducted by 78 consumers between 15 and 25 years of age. The consumers evaluated the global acceptance of the formulations through the structured 9-point hedonic scale, in a single section, in a monadic form. The experiment was structured by a Randomized Complete Block Design. The results were submitted to the analysis of variance, Tukey test, and to the preference mapping technique for principal component analysis. The control samples and the others with FOS had the better acceptance. The sample containing solely FOS was the closest to the traditional product with little difference from the latter in terms of global acceptance. The granola was statistically different from the traditional product. The fiber concentration analyzed was higher than the one provided by the granola supplier. The fiber concentrations in the ice creams varied from 0,9 to 5,45 g.100 g –1 . The highest

Modulators of erythrocyte glutathione peroxidase activity in healthy adults: an observational study.

Abstract The aim of this study was to investigate the potential modulators of erythrocyte glutathione peroxidase (GPx) activity in young and apparently healthy individuals. One hundred one individuals (53 women and 48 men) were evaluated for anthropometric measurements, biochemical markers, clinical, dietary, and endogenous and exogenous components of the antioxidant defense system. Statistical analysis was performed to detect differences among subjects by the median of GPx activity. A linear regression model and Spearman correlation coefficients were used to screen the associations between GPx activity and interest variables. Individuals with higher GPx enzymatic activity were older and higher circulating levels of oxidized low-density lipoprotein (ox-LDL) values, but conversely lower nail concentrations of selenium and copper (P < 0.05). The GPx activity was positively correlated to truncal fat percentage values (r = 0.24, P = 0.016), circulating levels of ox-LDL (r = 0.28, P = 0.004), and daily vitamin C intake (r = 0.28, P = 0.007), and negatively correlated to the nail concentration of selenium (r = −0.24, P = 0.026). Interesting, it was noticed that the truncal fat percentage and circulating levels of ox-LDL explained 5.9 and 7.4% of the GPx enzymatic activity. Thus, preventive measures such as adequate antioxidant intake and proper fat percentage would be a priority in the nutritional care of young and apparently healthy individuals.