Peroxidação lipídica e obesidade: Métodos para aferição do estresse oxidativo em obesos

Redox profile of silver catfish challenged with Aeromonas hydrophila and treated with hexane extract of Hesperozygis ringens (Benth.) Epling through immersion bath

The growing increase in the fish farming sector has favored the establishment of bacterial outbreaks caused by Aeromonas hydrophila in several species. The hexane extract of Hesperozygis ringens (HEHR) (Lamiaceae) leaves increased the survival rate of silver catfish (Rhamdia quelen) experimentally infected by A. hydrophila. However, it is noteworthy that no reports have been found on the possible mechanisms of action of this extract in infected fish. This study aimed to evaluate the effect of the HEHR, administered through single immersion bath, on lipid peroxidation and antioxidant defenses in muscle and liver tissue of silver catfish challenged with A. hydrophila. The results showed that the oxidative status of silver catfish was altered, although oxidative stress was not triggered during the experiment. HEHR at 30 mg/L (HEHR30) was not characterized as a pro-oxidant agent in the presence of infection, unlike florfenicol and HEHR at 15 mg/L treatments in some cases. In short, HEHR30 provided an important increase in hepatic catalase activity, characterizing one of the possible mechanisms involved in the greater survival of fish experimentally infected by A. hydrophila. Additionally, HEHR30 did not induce lipid peroxidation, nor reduced antioxidant defenses of silver catfish infected or not by A. hydrophila.

Constituents of Chamaecrista diphylla (L.) Greene Leaves with Potent Antioxidant Capacity: A Feature-Based Molecular Network Dereplication Approach

Chamaecrista diphylla (L.) Greene (Fabaceae/Caesalpiniaceae) is a herbaceous plant that is widely distributed throughout the Americas. Plants from this genus have been used in traditional medicine as a laxative, to heal wounds, and to treat ulcers, snake and scorpion bites. In the present study, we investigated the chemical composition of Chamaecrista diphylla leaves through a mass spectrometry molecular network approach. The oxygen radical absorbance capacity (ORAC) for the ethanolic extract, enriched fractions and isolated compounds was assessed. Overall, thirty-five compounds were annotated for the first time in C. diphylla. Thirty-two of them were reported for the first time in the genus. The isolated compounds 9, 12, 24 and 33 showed an excellent antioxidant capacity, superior to the extract and enriched fractions. Bond dissociation energy calculations were performed to explain and sustain the antioxidant capacity found. According to our results, the leaves of C. diphylla represent a promising source of potent antioxidant compounds.

Obesity, bariatric surgery and oxidative stress

Introduction:

Obesity refers to the accumulation of fatty tissues and it favors the occurrence of oxidative stress. Alternatives that can contribute to body weight reduction have been investigated in order to reduce the production of reactive oxygen species responsible for tissue damage. The aim of the current study was to assess whether the oxidant and antioxidant markers of obese women before and after bariatric surgery were able to reduce oxidative damage.

Method:

We have assessed 16 morbidly obese women five days before and 180 days after the surgery. The control group comprised 16 non-obese women. Levels of thiobarbituric acid-reactive substances, carbonylated proteins, reduced glutathione and ascorbic acid were assessed in the patients' plasma.

Results:

Levels of lipid peroxidation and protein carbonylation in the pre-surgical obese women were higher than those of the controls and post-surgical obese women. Levels of reduced glutathione in the pre-surgical obese women were high compared to the controls, and declined after surgery. Levels of ascorbic acid fell in the pre--surgical obese women compared to the control and post-surgical obese women.

Conclusion:

Body weight influences the production of reactive oxygen species. Bariatric surgery, combined with weight loss and vitamin supplementation, reduces cellular oxidation, thus reducing tissue damage.

Avaliação da ingestão de nutrientes antioxidantes pela população brasileira e sua relação com o estado nutricional

RESUMO: Introdução: O estudo dos antioxidantes dietéticos tem ganhado destaque em função da elucidação dos efeitos deletérios do estresse oxidativo ao organismo. Objetivo: Avaliar a ingestão de nutrientes antioxidantes pela população brasileira e sua relação com o estado nutricional. Métodos: Realizou-se um estudo transversal com coleta de dados secundários do consumo alimentar de 33.459 indivíduos de ambos os sexos, de 10 ou mais anos, de todas as regiões do Brasil, a partir dos microdados da Pesquisa de Orçamentos Familiares (2008 - 2009), Inquérito Nacional de Alimentação. Foram analisados os teores das vitaminas E, A e C, zinco, manganês, cobre e selênio de 188 itens alimentares, divididos em 12 grupos, conforme a forma habitual de consumo. As médias de ingestão dos nutrientes antioxidantes de acordo com o estado nutricional foram comparadas por meio do teste t de Bonferroni. Resultados: Foram observados maiores percentuais de ingestão insuficiente para as vitaminas do que para os minerais antioxidantes. Notou-se diferença significativa na ingestão da vitamina E em relação ao estado nutricional, sendo que a ingestão por indivíduos com excesso de peso foi inferior em relação aos com peso adequado. Verificou-se que os indivíduos com baixo peso apresentaram menor ingestão de quase todos os minerais antioxidantes, exceto o cobre, em que a ingestão por indivíduos com baixo peso foi igual à ingestão por aqueles com peso adequado. Conclusão: Elevados percentuais de ingestão insuficiente de nutrientes antioxidantes foram observados na população estudada, especialmente para as vitaminas. Além disso, a ingestão de nutrientes antioxidantes variou conforme o estado nutricional, o sexo e o estágio de vida.

Role of Magnesium in Oxidative Stress in Individuals with Obesity

Adipose tissue is considered an endocrine organ that promotes excessive production of reactive oxygen species when in excess, thus contributing to lipid peroxidation. Magnesium deficiency contributes to the development of oxidative stress in obese individuals, as this mineral plays a role as an antioxidant, participates as a cofactor of several enzymes, maintains cell membrane stability and mitigates the effects of oxidative stress. The objective of this review is to bring together updated information on the participation of magnesium in the oxidative stress present in obesity. We conducted a search of articles published in the PubMed, SciELO and LILACS databases, using the keywords 'magnesium', 'oxidative stress', 'malondialdehyde', 'superoxide dismutase', 'glutathione peroxidase', 'reactive oxygen species', 'inflammation' and 'obesity'. The studies show that obese subjects have low serum concentrations of magnesium, as well as high concentrations of oxidative stress marker in these individuals. Furthermore, it is evident that the adequate intake of magnesium contributes to its appropriate homeostasis in the body. Thus, this review of current research can help define the need for intervention with supplementation of this mineral for the prevention and treatment of disorders associated with this chronic disease.

Effects of the Intake of Sesame Seeds (Sesamum indicum L.) and Derivatives on Oxidative Stress: A Systematic Review

This study is aimed at assessing the scientific evidence on the effect of the intake of sesame seeds and derivatives on oxidative stress of individuals with systemic hypertension, dyslipidemia, and type 2 diabetes mellitus. A systematic review was conducted in seven databases (Lilacs, PubMed, ISI Web of Knowledge, Cochrane Library, Scopus, Trip Database, and Scielo) from September 2013 to January 2014. Clinical trials on the intake of sesame seeds and derivatives assessing the outcomes related to oxidative stress were retrieved. The risk of bias in the results of the studies selected was assessed according to the criteria of the Cochrane Handbook for Systematic Reviews of Interventions. This review included seven clinical trials showing that the intake of sesame resulted in the increase in enzymatic and nonenzymatic antioxidants, as well as in a reduction in oxidative stress markers. This was mainly observed with the use of sesame oil for hypertensive individuals during 2 months and black sesame meal capsules for prehypertensive individuals during four weeks. Most studies involved a small number of participants, sample size being considered a limiting factor for this review. In addition, a significant heterogeneity was observed in the type of population studied and the type of sesame and derivatives used, as well as their amount. The follow-up time was considered a limiting factor, because it varied in the different studies. The high risk of randomization and blinding biases found in the studies assessed determines lower scientific evidence of the results. Despite the limitations and biases identified in this systematic review, sesame showed relevant effects on oxidative stress, suggesting it could increase the antioxidant capacity.