952 resultados para Antioxidant activity index


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The anthracyclines constitute a group of drugs widely used for the treatment of a variety of human tumors. However, the development of irreversible cardiotoxicity has limited their use. Anthracycline-induced cardiotoxicity can persist for years with no clinical symptoms. However, its prognosis becomes poor after the development of overt heart failure, possibly even worse than ischemic or idiopathic dilated cardiomyopathies. Due to the successful action of anthracyclines as chemotherapic agents, several strategies have been tried to prevent/ attenuate their side effects. Although anthracycline-induced injury appears to be multifactorial, a common denominator among most of the proposed mechanisms is cellular damage mediated by reactive oxygen species. However, it remains controversial as to whether antioxidants can prevent such side effects given that different mechanisms may be involved in acute versus chronic toxicity. The present review applies a multisided approach to the critical evaluation of various hypotheses proposed over the last decade on the role of oxidative stress in cardiotoxicity induced by doxorubicin, the most used anthracycline agent. The clinical diagnosis and treatment is also discussed. © 2008 Bentham Science Publishers Ltd.

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Stem cuts and seeds of Salvia officinalis were incubated on nutrient media for plantlets production and analysis of the total phenolic compounds, total flanovoids and antioxidant activity in micropropagated plants. Explants were obtained from seedlings and inoculated on MS with different concentrations of benzylaminopurine (BAP) and indolbutyric acid (IBA). After 30 and 60 days of incubation, the explants were scored for percentage of contaminated, dead and oxidized explants and mean bud numbers. For bud formation, the most efficient treatment was the medium containing BAP at 1 mg L-1, for the plantlet height the better medium was the control without the addition of plant regulator. IBA promoted the formation of few roots. Our results indicated that stem cuts incubated on media containing BAP and/or IBA did not increase the total flavonoid contents, but increased the total phenolics' by BAP and high antioxidant activity by 1 mg L-1 BAP.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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This work aimed to characterize the proximate composition, antioxidant activity and fatty acids profile and tocopherol composition of the oil from Eugenia dysenterica DC seeds. To obtain the extract, the dehydrated and triturated seeds were extracted with ethyl alcohol for 30 minutes, at a proportion of 1:3 of seeds:ethyl alcohol, under continuous agitation at room temperature. Afterwards, the mixture was filtered and the supernatant was dehydrated at 40°C in order to determine by direct weighing the dry matter yield of the extract. The cagaita seeds showed to be an important source of total carbohydrates, had relevant antioxidant activity and a high content of total phenolic compounds. In comparison to other oils and fats, cagaita seeds oil do not constitutes a good source of tocopherols.

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The aim of this work was to investigate monthly, for one year the seasonality effect on the physicochemical properties (dry weight, flavonoids contents, pH and antioxidant activity) of ethanolic extract (EAP) of propolis produced by three different techniques (intelligent propolis collector, plastic screen or scraping) fifteen colonies of africanized bees. No differences (p>0.05) in the physicochemical properties due to the technique of propolis production and seasonality were observed.

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Flavonoids have been widely incorporated into cosmetic and dermatological formulations, affording benefits such as antioxidant action, improved skin tone and fewer lines and wrinkles. Brazil has a huge biodiversity, with one of the richest flora in the world, and existing studies justify the quest for greater research efforts in this area. The cajazeira (Spondias lutea L.), a plant of the Anacardiaceae family from tropical America, is widely disseminated in Brazil. This plant was chosen because of the presence of flavonoids that exhibit antioxidant activity. The purpose of this research was to develop a stable topical formulation containing Spondias lutea extract with the aim of preventing skin diseases caused by UV radiation. Hydro ethanolic extract of Spondias lutea fruit was prepared and assayed for its the flavonoids content. The antioxidant activity was estimated by DPPH and superoxide assay. The physicochemical stability and skin permeation of the cream containing 8% (w/w) of extract were assessed. The results showed that the S. lutea extract possessed antioxidant activity, and that it is possible to obtain a stable cosmetic containing the extract, which is able to penetrate the skin. Thus, it is possible to use this extract to produce an anti-aging cosmetic.

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Background and Objective: Simple Measure of the Impact of Lupus Erythematosus in Youngsters (SMILEY) is a health-related quality of life (HRQOL) assessment tool for pediatric systemic lupus erythematosus (SLE), which has been translated into Portuguese for Brazil. We are reporting preliminary data on cross-cultural validation and reliability of SMILEY in Portuguese (Brazil). Methods: In this multi-center cross-sectional study, Brazilian children and adolescents 5-18 years of age with SLE and parents participated. Children and parents completed child and parent reports of Portuguese SMILEY and Portuguese Pediatric Quality of Life Inventory (PedsQLTM) Generic and Rheumatology modules. Parents also completed the Childhood Health Assessment Questionnaire (CHAQ). Physicians completed the SLE disease activity index (SLEDAI), Physician's Global Assessment of disease activity (PGA) and Systemic Lupus Erythematosus International Collaborating Clinics ACR Damage Index (SDI). Results: 99 subjects (84 girls) were enrolled; 93 children and 97 parents filled out the SMILEY scale. Subjects found SMILEY relevant and easy to understand and completed SMILEY in 5-15 minutes. Brazilian SMILEY was found to have good psychometric properties (validity and reliability), and the child-parent agreement was moderate. Conclusion: SMILEY may eventually be used routinely as a research/clinical tool in Brazil. It may be also adapted for other Portuguese-speaking nations offering critical information regarding the effect of SLE on HRQOL for children with SLE. © The Author(s), 2012.

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Studies have shown that Casearia sylvestris compounds protect DNA from damage both in vitro and in vivo. Complementarily, the aim of the present study was to assess the chemopreventive effect of casearin B (CASB) against DNA damage using the Ames test, the comet assay and the DCFDA antioxidant assay. The genotoxicity was assessed by the comet assay in HepG2 cells. CASB was genotoxic at concentrations higher than 0.30μM when incubated with the FPG (formamidopyrimidine-DNA glycosylase) enzyme. For the antigenotoxicity comet assay, CASB protected the DNA from damage caused by H2O2 in the HepG2 cell line in concentrations above 0.04μM with post-treatment, and above 0.08μM with pre-treatment. CASB was not mutagenic (Ames test) in TA 98 and TA 102. In the antimutagenicity assays, the compound was a strong inhibitor against aflatoxin B1 (AFB) in TA 98 (>88.8%), whereas it was moderate (42.7-59.4%) inhibitor against mytomicin C (MMC) in TA 102. Additionally, in the antioxidant assay using DCFDA, CASB reduced reactive oxygen species (ROS) generated by H2O2. In conclusion, CASB was genotoxic to HepG2 cells at high concentrations; was protective of DNA at low concentrations, as shown by the Ames test and comet assay; and was also antioxidant. © 2012 Elsevier Ltd.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Since the beginning of propolis research, several groups have studied its antibacterial, antifungal, and antiviral properties. However, most of these studies have only employed propolis ethanolic extract (PEE) leading to little knowledge about the biological activities of propolis water extract (PWE). Based on this, in a previous study, we demonstrated the anti-inflammatory and immunomodulatory activities of PWE. In order to better understand the equilibrium between effectiveness and toxicity, which is essential for a new medicine, the characteristics of PWE were analyzed. We developed and validated an RP-HPLC method to chemically characterize PWE and PEE and evaluated the in vitro antioxidant/antimicrobial activity for both extracts and the safety of PWE via determining genotoxic potential using in vitro and in vivo mammalian micronucleus assays. We have concluded that the proposed analytical methodology was reliable, and both extracts showed similar chemical composition. The extracts presented antioxidant and antimicrobial effects, while PWE demonstrated higher antioxidant activity and more efficacious for the most of the microorganisms tested than PEE. Finally, PWE was shown to be safe using micronucleus assays. © 2013 Bruno Alves Rocha et al.

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To assess the effects of continuous exercise training at intensities corresponding to 80 and 90 % of the lactate minimum test (LM), we evaluated antioxidant activity, hormone concentration, biochemical analyses and aerobic and anaerobic performance, as well as glycogen stores, during 12 weeks of swimming training in rats. One-hundred rats were separated into three groups: control (CG, n = 40), exercise at 80 (EG80, n = 30) and 90 % (EG90, n = 30) of LM. The training lasted 12 weeks, with sessions of 60 min/day, 6 days/week. The intensity was based at 80 and 90 % of the LM. The volume did not differ between training groups (Ẋ of EG80 = 52 ± 4 min; Ẋ of EG90 = 56 ± 2 min). The glycogen concentration (mg/100 mg) in the gastrocnemius increased after the training in EG80 (0.788 ± 0.118) and EG90 (0.795 ± 0.157) in comparison to the control (0.390 ± 0.132). The glycogen stores in the soleus enhanced after the training in EG90 (0.677 ± 0.230) in comparison to the control (0.343 ± 0.142). The aerobic performance increased by 43 and 34 % for EG80 and EG90, respectively, in relation to baseline. The antioxidant enzymes remain unchanged during the training. Creatine kinase (U/L) increased after 8 weeks in both groups (EG80 = 427.2 ± 97.4; EG90 = 641.1 ± 90.2) in relation to the control (246.9 ± 66.8), and corticosterone (ng/mL) increased after 12 weeks in EG90 (539 ± 54) in comparison to the control (362 ± 44). The continuous exercise at 80 and 90 % of the LM has a marked aerobic impact on endurance performance without significantly biomarkers changes compared to control. © 2013 Springer-Verlag Berlin Heidelberg.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Ten Brazilian medicinal plants used to treat gastritis and ulcers were carefully selected on the basis of ethnopharmacological importance and antiulcerogenic activity previously described. The antioxidant activity of the methanolic extracts was determined in analysis conditions that simulate a real biological activity on inhibition of the oxidative burst induced in neutrophils using Helicobacter pylori as activator, by a luminol-amplified chemiluminescence assay. The extracts, at low concentration (5 g/mL), exhibited a large variation in inhibitory effects of H. pylori-induced oxidative burst ranging from 48% inhibition to inactive, but all extracts, excluding Byrsonima intermedia, had inhibitory activity over 80% at the concentration of 100 g/mL. The total suppressive antioxidant capacity measured as the effective concentration, which represents the extract concentration producing 50% inhibition of the chemiluminescence induced by H. pylori, varies from 27.2 to 56.8 g/mL and was in the following order: Qualea parviflora > Qualea multiflora > Alchornea triplinervia > Qualea grandiflora > Anacardium humile > Davilla elliptica > Mouriri pusa > Byrsonima basiloba > Alchornea glandulosa > Byrsonima intermedia. The main groups of compounds in tested extracts are presented. Differences in the phytochemical profile, quantitatively and qualitatively, of these plants can explain and justify their protective effect on the gastric mucosa caused by the neutrophil-generated ROS that occurs when H. pylori displays its evasion mechanisms. © 2013 Cibele Bonacorsi et al.

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Ethnopharmacological relevance Propolis is a bee product with numerous biological and pharmacological properties, such as immunomodulatory and anti-inflammatory activities. It has been used in folk medicine as a healthy drink and in food to improve health and prevent inflammatory diseases. However, little is known about its mechanism of action. Thus, the goal of this study was to verify the antioxidant activity and to explore the anti-inflammatory properties of propolis by addressing its intracellular mechanism of action. Caffeic acid was investigated as a possible compound responsible for propolis action. Materials and methods The antioxidant properties of propolis and caffeic acid were evaluated by using the 2,2-Diphenyl-1-picrylhydrazyl free radical (DPPH) scavenging method. To analyze the anti-inflammatory activity, Raw 264.7 macrophages were treated with different concentrations of propolis or caffeic acid, and nitric oxide (NO) production, a strong pro-inflammatory mediator, was evaluated by the Griess reaction. The concentrations of propolis and caffeic acid that inhibited NO production were evaluated on intracellular signaling pathways triggered during inflammation, namely p38 mitogen-activated protein kinase (MAPK), c-jun NH2-terminal kinase (JNK1/2), the transcription nuclear factor (NF)-κB and extracellular signal-regulated kinase (ERK1/2), through Western blot using specific antibodies. A possible effect of propolis on the cytotoxicity of hepatocytes was also evaluated, since this product can be used in human diets. Results Caffeic acid showed a higher antioxidant activity than propolis extract. Propolis and caffeic acid inhibited NO production in macrophages, at concentrations without cytotoxicity. Furthermore, both propolis and caffeic acid suppressed LPS-induced signaling pathways, namely p38 MAPK, JNK1/2 and NF-κB. ERK1/2 was not affected by propolis extract and caffeic acid. In addition, propolis and caffeic acid did not induce hepatotoxicity at concentrations with strong anti-inflammatory potential. Conclusions Propolis exerted an antioxidant and anti-inflammatory action and caffeic acid may be involved in its inhibitory effects on NO production and intracellular signaling cascades, suggesting its use as a natural source of safe anti-inflammatory drugs. © 2013 Elsevier B.V.