Iara Barros Valentim

Fontes vegetais naturais de antioxidantes

Growing knowledge on the health-promoting impact of antioxidants in everyday foods, combined with the assumption that a number of common synthetic preservatives may have hazardous side effects has led to increased investigations in the field of natural antioxidants, principally those found in plants. Food industries normally discard plant residues that could benefit the human health and diminish undesirable environmental impact. Once estimated the content of antioxidants in these residues, advantageous economical and social alternatives to the discard are possible, for example, their use for preparation of nutraceuticals to be offered to low-income populations. We present here a broad, although not complete, account of the continuously growing knowledge on the antioxidant capacity of whole fruits, seeds and peels, cereals, vegetal oils and aromatic plants, at several physical forms, as well as a description of the usual methods for evaluating their antioxidant capacity and examples of agroindustrial processes that could be harnessed for the production of antioxidant supplement food, along with research perspectives in the area.

Development of Nonalcoholic Hepatopathy: Contributions of Oxidative Stress and Advanced Glycation End Products

Advanced glycation end products (AGEs) are generated spontaneously in cells; however, under conditions of hyperglycemia and lipid peroxidation, their levels are higher than usual, which contribute to the development of diseases such as the nonalcoholic fatty liver disease (NAFLD). NAFLD is associated with oxidative stress (OS), which is linked to the transition of steatosis to steatohepatitis due to lipid peroxidation. The AGE-receptor interaction in hepatic stellate cells leads to an increase in reactive oxygen species and enhances the proliferation and activation of these cells, worsening liver fibrosis and disease progression. In this vicious cycle, there is production of (carboxymethyl)lysine, a biomarker for products of advanced glycation and lipid peroxidation, being a shared component between the two pathways. In this review, we aim to compile evidence to support the basic molecular mechanisms of AGEs and OS generation and their influence, independently or combined, on the evolution of NAFLD. The deeper understanding of the interrelations of AGEs + OS may help to elucidate the pathogenic pathways of NAFLD and to devise rational therapeutic interventions for this disease, with an expected positive impact on quality of life of patients.

Cocos nucifera Linn. (Palmae) husk fiber ethanolic extract: antioxidant capacity and electrochemical investigation.

The present study aims to determine the antioxidant capacity of the ethanolic extracts of husk fiber of four coconut (Cocos nucifera L.) varieties (yellow dwarf, green dwarf, giant and hybrid) and to evaluate the electrochemical behavior of these extracts on a glassy carbon electrode and on a modified glassy carbon electrode. The highest values of total phenolic content were obtained for the hybrid (531 ± 24 mg GAE g(-1) dry extract) and yellow dwarf (501 ± 29 mg GAE g(-1) dry extract) varieties and the lowest was for the green dwarf variety with 58 ± 9 mg GAE g(-1) dry extract. The ability of the extracts to scavenge DPPH˙ radicals was in the order of giant > yellow dwarf > hybrid > green dwarf and the IC50 values varied from 8.6 to 55.9 μg mL(-1). All varieties showed reducing potential by the use of FRAP and CUPRAC methods, with the lowest performance obtained for the green dwarf variety. Additionally, through the use of mimetic biomembranes, ethanolic extracts of coconut husk were shown to protect lipids against oxidative damage independent of the variety. The main antioxidants identified in the extract of yellow dwarf variety by UPLC-MS were quercetin and catechin. Cyclic voltammetric studies of the ethanolic extracts on glassy carbon electrode confirmed the presence of easily oxidized compounds, and the high antioxidant capacity of the varieties. This capacity was expressed as mg quercetin equivalents g(-1) dry extract and ranged from 25.9 up to 53.5 mg QE g(-1). A poly-xanthurenic acid (poly-Xa)/multi-walled carbon nanotube (MWCNT) / glassy carbon modified electrode (poly-Xa/MWCNT/GCE) was used for this purpose. Our findings suggest that these extracts are potentially important antioxidant supplements for the everyday human diet, pharmaceutical and cosmetic industries, thereby aggregating value to the enormous amount of waste from the coconut industry, mostly used for burning purposes.

Choline and Cystine Deficient Diets in Animal Models with Hepatocellular Injury: Evaluation of Oxidative Stress and Expression of RAGE, TNF-α, and IL-1β

This study aims to evaluate the effects of diets deficient in choline and/or cystine on hepatocellular injury in animal models (young male Wistar rats, aged 21 days), by monitoring some of the oxidative stress biomarkers and the expression of RAGE, TNF-α, and IL-1β. The animals were divided into 6 groups (n = 10) and submitted to different diets over 30 days: AIN-93 diet (standard, St), AIN-93 choline deficient (CD) diet and AIN-93 choline and cystine deficient (CCD) diet, in the pellet (pl) and powder (pw) diet forms. Independently of the diet form, AIN-93 diet already led to hepatic steatosis and CD/CCD diets provoked hepatic damage. The increase of lipid peroxidation, represented by the evaluation of thiobarbituric acid reactive species, associated with the decrease of levels of antioxidant enzymes, were the parameters with higher significance toward redox profile in this model of hepatic injury. Regarding inflammation, in relation to TNF-α, higher levels were evidenced in CD(pl), while, for IL-1β, no significant alteration was detected. RAGE expression was practically the same in all groups, with exception of CCD(pw) versus CCD(pl). These results together confirm that AIN-93 causes hepatic steatosis and choline and/or cysteine deficiencies produce important hepatic injury associated with oxidative stress and inflammatory profiles.

Adsorption studies of trifluralin on chitosan and its voltammetric determination on a modified chitosan glassy carbon electrode

Os estudos sobre adsorcao do herbicida trifluralina (TRF) em quitosana foram realizados em batelada, usando temperaturas entre 298 e 313 K. Os resultados de adsorcao ajustaram-se perfeitamente ao modelo de adsorcao de Langmuir. O valor de entalpia obtido -10,2 ± 0,8 kJ mol-1 confirma que a interacao TRF-quitosana e exotermica e que o processo de adsorcao e relativo a interacao eletrostatica entre o grupo amonio da quitosana e o dipolo negativo dos grupos substituintes de TRF, sendo dependente da forca ionica. Estudos voltametricos mostraram que TRF apresentou dois picos de reducao em eletrodo de CV, ambos de natureza difusional e irreversivel, referentes a reducao dos grupos nitroaromaticos. A corrente do primeiro pico de reducao intensificou-se no eletrodo de carbono vitreo modificado com quitosana, em comparacao com o eletrodo nao modificado. Isto foi atribuido a adsorcao/acumulacao de TRF em quitosana. A corrente de reducao em voltametria de pulso diferencial foi proporcional a concentracao de TRF na faixa de 2,49 × 10-7 a 5,79 × 10-6 mol L-1, com limite de deteccao de 7,45 × 10-8 mol L-1.

Antioxidant Capacity, Physicochemical and Floral Characterization of Honeys from the Northeast of Brazil

The aim of this work was to evaluate floral origin, physicochemical quality and antioxidant capacity of 15 honey samples, from a semi-arid region in the northeast of Brazil and to correlate data with color and total phenolic content (TPC). A predominance of amber color was observed. The majority of samples were classified as polifloral and only two samples (the light yellow ones) were monofloral. TPC values ranged from 27.0 to 92.7 mg GAE 100 g -1 of honey, being higher in darker samples. All samples had ability to scavenge DPPH  radicals and showed reducing potential analyzed by FRAP and CUPRAC methods, with the highest performance obtained in darker samples. TPC shows good positive correlations (p<0.05) with the methods used to evaluate antioxidant capacity. Significant correlations (p<0.01) between color and TPC (0.82) and also with reducing power, using CUPRAC (0.66) were observed. The darker color of honey is indicative of higher phenol content and antioxidant capacity. The reported characteristics give an enhanced functional food property to honey and contribute to the development of the regional economy, providing an alternative to family income increase.

Polyphenol profile by UHPLC-MS/MS, anti-glycation, antioxidant and cytotoxic activities of several samples of propolis from the northeastern semi-arid region of Brazil

Abstract Context: Propolis has promising biological activities. Propolis samples from the Northeast of Bahia, Brazil – sample A from Ribeira do Pombal and B, from Tucano – were investigated, with new information regarding their biological activities. Objective: This paper describes the chemical profile, antioxidant, anti-glycation and cytotoxic activities of these propolis samples. Material and methods: Ethanol extracts of these propolis samples (EEP) and their fractions were analyzed to determine total phenolic content (TPC); antioxidant capacity through DPPH•, FRAP and lipid peroxidation; anti-glycation activity, by an in vitro glucose (10 mg/mL) bovine serum albumine (1 mg/mL) assay, during 7 d; cytotoxic activity on cancer (SF295, HCT-116, OVCAR-8, MDA-MB435, MX-1, MCF7, HL60, JURKAT, MOLT-4, K562, PC3, DU145) and normal cell lines (V79) at 0.04–25 μg/mL concentrations, for 72 h. The determination of primary phenols by ultra high-pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) and volatile organic compounds content by gas chromatography-mass spectrometry (GC-MS) were also performed. Results: The EEP polar fractions exhibited up to 90% protection against lipid peroxidation. The IC50 value for anti-glycation activity of EEP was between 16.5 and 19.2 μg/mL, close to aminoguanidine (IC50 = 7.7 μg/mL). The use of UHPLC-MS/MS and GC-MS allowed the identification of 12 bioactive phenols in the EEP and 24 volatile compounds, all already reported. Conclusions: The samples present good antioxidant/anti-glycation/cytotoxic activities and a plethora of biologically active compounds. These results suggest a potential role of propolis in targeting ageing and diseases associated with oxidative and carbonylic stress, aggregating value to them.

Conteúdo Total de Fenóis em Sucos de Frutas Tropicais Engarrafados

The Artists’ Home in Ilheus BA Brazil and its history, economy and culture are provided so that the memory of the institution may be exhibited to the academic and local communities for their sustainability within the three aspects analyzed. The qualitative and descriptive methodology developed from an analysis of documents and other sources is foregrounded by Rehem (2001); Vinhaes (2001); Sarlo (2001); Campos (2006); Simoes (2006); Voisin (2006); Dias and Carrara (2007); Costa and Gândara (2009) and Souza (2009). A discussion on the Artists’ Home is also a debate on its financial crises. The mid-2005 and the 2009 crises almost made its closure mandatory if the initiative of Ilheus artists had not come to the rescue with artistic productions and with cultural and literary events kept alive up to the present. Since the Artists’ Home produces culture and broadcasts the historical and economical regional context, coupled to its contribution towards tourism and local culture, it certainly provides opportunities and development focuses on the appreciation of regional.Communication established in the familiar environment makes possible the learning of values and behavior patterns and influences the construction of factors that interfere decisively on children’s social, emotional and cognitive development. Current research investigates the communication patterns and the interaction between parents and offspring and their possible influence on children’s school performance. Two groups of pupils of an educational institution were compared. Twelve individuals, six children and their respective mothers, answered a questionnaire on communication and interaction between parents and their children. Among the children, three had good performance in school activities, whereas the other three had difficulties. Results show that the answers given by the group of children with good school performance and their mothers were close in all investigated items. On the other hand, answers from the group of children with difficulties were contradictory, especially on the items related to communication and interaction during leisure activities. Data suggest that in the second group the children’s perception on the relationship between them and their mothers is highly different from the image that their mothers have about this relationship. This fact demonstrates patterns of inadequate interaction and communication. Since communication and interaction quality between the children and their mothers were better in the first group, this fact confirms the hypothesis that good communication and interaction between parents and offspring interferes positively on the children’s school performance.