Avaliação termoanalítica da eficiência de antioxidantes na estabilidade oxidativa do biodiesel de mamona

The biodiesel is defined as the mono-alkyl ester derived from long-chain fatty acids, from renewable sources such as vegetable oils or animal fat, whose use is associated with the replacement of fossil fuels in diesel engine cycle. The biodiesel is susceptible to oxidation when exposed to air and this process of oxidation affects the quality of fuel, mainly due to long periods of storage. Because of this, the oxidation stability has been the focus of numerous researches since it directly affects the producers, distributors and users of fuel. One of the possibilities to increase the resistance of biodiesel is the autoxidation treatment with inhibitors of oxidation. The antioxidants can be used as potential inhibitors of the effects of oxidation on the kinematic viscosity and the index of acidity of biodiesel, thereby increasing oxidative stability. This work aims to examine the efficiency of antioxidants, α-tocopherol and butylated hydroxy-toluene (BHT), added the biodiesel content of remembrance through Pressurized-Differential Scanning Calorimetry (P-DSC), Thermogravimetry (TG) and Petrology. The results showed that the use of antioxidant BHT, at the concentration of 2000ppm, increased resistance to oxidation of the biodiesel and oxidative induction time (OIT), which is a better result as antioxidant than the α-tocopherol. With the thermogravimetric analysis, it was observed that the biodiesel presented an initial decomposition temperature of lower tendency than that of oil, demonstrating to be more volatile, bearing great similarity to the diesel and being characterized as an alternative fuel. The rheological analysis indicated that each sample of biodiesel behaved as a Newtonian fluid

Avaliação da estabilidade térmica e oxidativa do biodiesel de algodão e do efeito da adição de antioxidantes (α-tocoferol e BHT)

This work aims to study the effects of adding antioxidants, such as, α- tocopherol and BHT on the thermal and oxidative stability of biodiesel from cottonseed (B100). The Biodiesel was obtained through the methylical and ethylical routes. The main physical and chemical properties of cotton seed oil and the B100 were determined and characterized by FTIR and GC. The study of the efficiency of antioxidants, mentioned above, in concentrations of 200, 500, 1000, 1500, 2000ppm, to thermal and oxidative stability, was achieved by Thermogravimetry (TG), Differential Thermal Analysis (DTA), Differential Scanning Calorimetry (DSC), Differential Scanning Calorimetry - Hi-Pressure (P-DSC) and Rancimat. The Biodiesel obtained are within the specifications laid down by Resolution of ANP No7/2008. The results of TG curves show that the addition of both antioxidants, even in the lowest concentration, increases the thermal stability of Biodieseis. Through the DTA and DSC it was possible to study the physical and chemical transitions occurred in the process of volatilization and decomposition of the material under study. The initial time (OT) and temperature (Tp) of oxidation were determined through the P-DSC curve and they showed that the α-tocopherol has a pro-oxidant behavior for some high concentrations. The BHT showed better results than the α-tocopherol, with regard to the resistance to oxidation

DNA damage in peripheral blood mononuclear cells of patients undergoing anti-tuberculosis treatment

Tuberculosis (TB), a chronic infectious disease, is a major cause of morbidity and mortality worldwide. Expression of iNOS and consequent production of NO during the inflammatory process is an important defense mechanism against TB bacteria. We have tested whether pulmonary TB patients undergoing anti-tuberculosis treatment present DNA damage, and whether this damage is related to oxidative stress, by evaluating total hydrophilic antioxidant capacity and iNOS expression. DNA damage in peripheral blood mononuclear cells from patients and healthy tuberculin test (PPD) positive controls was evaluated by single-cell gel electrophoresis (comet assay), and iNOS expression was measured by qPCR. We also evaluated total hydrophilic antioxidant capacity in plasma from patients and controls. Compared to controls, pulmonary TB patients under treatment presented increased DNA damage, which diminished during treatment. Also, the antioxidant capacity of these individuals was increased at the start of treatment, and reduced during treatment. TB patients showed lower iNOS expression, but expression tended to increase during treatment. Our results indicate that pulmonary TB patients under anti-TB treatment exhibit elevated DNA damage in peripheral blood mononuclear cells. This damage was not related to nitric oxide but may be due to other free radicals. (C) 2012 Elsevier B.V. All rights reserved.

Antioxidant supplementation and premature rupture of the membranes: a planned secondary analysis

OBJECTIVE: The purpose of this study was to determine if antioxidant supplementation during pregnancy reduces the incidence of premature rupture of the membranes (PROM).STUDY DESIGN: A placebo-controlled, double-blind trial was conducted. PROM and preterm PROM (PPROM) were planned secondary outcomes of the trial. Women between 12(0/7) and 19(6/7) weeks of gestation and diagnosed to have chronic hypertension or a prior history of preeclampsia were randomized to daily treatment with both vitamin C (1000 mg) and E (400 IU) or placebo.RESULTS: Outcome data for PROM were available for 697 of 739 patients. The rates of PROM (37/349 [10.6%] vs 19/348 [5.5%]; adjusted risk ratio [RR] 1.89 [95.42% CI, 1.11-3.23]; P = .015), and PPROM (16/349 [4.6%] vs 6/348 [1.7%]; RR 2.68 [1.07-6.71]; P = .025) were increased in the antioxidant group.CONCLUSION: Contrary to expectations, vitamins C and E supplementation in this dose combination may be associated with an increased risk of PROM and PPROM.

The impact of prior preeclampsia on the risk of superimposed preeclampsia and other adverse pregnancy outcomes in patients with chronic hypertension

OBJECTIVE: We sought to compare the rates of superimposed preeclampsia and adverse outcomes in women with chronic hypertension with or without prior preeclampsia.STUDY DESIGN: We conducted secondary analysis of 369 women with chronic hypertension (104 with prior preeclampsia) enrolled at 12-19 weeks as part of a multisite trial of antioxidants to prevent preeclampsia (no reduction was found). Outcome measures were rates of superimposed preeclampsia and other adverse perinatal outcomes.RESULTS: Prepregnancy body mass index, blood pressure, and smoking status at enrollment were similar between groups. The rates of superimposed preeclampsia (17.3% vs 17.7%), abruptio placentae (1.0% vs 3.1%), perinatal death (6.7% vs 8.7%), and small for gestational age (18.4% vs 14.3%) were similar between groups, but preterm delivery <37 weeks was higher in the prior preeclampsia group (36.9% vs 27.1%; adjusted risk ratio, 1.46; 95% confidence interval, 1.05-2.03; P = .032).CONCLUSION: In women with chronic hypertension, a history of preeclampsia does not increase the rate of superimposed preeclampsia, but is associated with an increased rate of delivery at <37 weeks.

High-frequency oscillatory ventilation attenuates oxidative lung injury in a rabbit model of acute lung injury

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

Influence of diet on oxidative DNA damage, uracil misincorporation and DNA repair capability

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

Porcentagens de saponinas e taninos em vinte e oito cultivares de alfafa (Medicago sativa L.) em duas épocas de corte - Botucatu - SP

O objetivo do estudo foi determinar os conteúdos de saponinas, taninos e a solubilidade da proteína (SP) de 28 cultivares de alfafa: Crioula, Monarca, BR 4, Alto Great, MH 4, SW 9210 A, 5929, BR 1, EL Grande, 5715, MH 15, Valley Plus, BR 2, Rio, SW 8210, Maricopa, ICI 990, 5888, P 30, Alfa-200, WL 516, SW 8112 A, BR 3, Florida 77, Araucana, Falcon, Semit 921 e Sutter. O material analisado foi obtido do 10º e 14º corte, respectivamente; em 08/12/97 e 16/04/98, de um experimento desenvolvido na Faculdade de Medicina Veterinária e Zootecnia, UNESP, Botucatu. Amostras de cada cultivar foram colhidas, pesadas e secas em estufa a 52ºC. As saponinas foram extraídas com solvente hidrofílico e lipofílico e o conteúdo foi calculado pela equação y=0,8121x-1,4759, R² = 1,00. A extração dos taninos totais e condensados foi efetuada por meio de ultra-som (12 min), sendo os taninos totais determinados pela equação: y=44,978 + 0,5644 com R²=0,9977 e os condensados, multiplicando-se a absorbância por 78,26 dividido pelo teor de matéria seca. A SP foi determinada pelo método de KOH, de acordo com a seguinte fórmula: SP (%) = proteína solúvel x 100/proteína bruta da amostra. Os teores de saponinas, taninos totais e condensados e a solubilidade da proteína não diferiram (P>0,05) entre as cultivares. Houve efeito (P<0,05) da época de corte apenas sobre o teor de taninos totais. Os teores médios de saponinas de 1,00% aliados à baixa solubilidade média da proteína bruta (34,11%) não se constituem em fatores limitantes para uso dos cultivares de alfafa estudadas.

Dietas vegetarianas e desempenho esportivo

As evidências atuais apontam benefícios da dieta vegetariana para a saúde humana. Contudo, a partir da adoção de práticas vegetarianas mais restritivas, confirmam-se os riscos à saúde. As dietas vegetarianas são caracterizadas pelo elevado consumo de carboidratos, fibras, magnésio, potássio, folato e antioxidantes, podendo apresentar deficiências em aminoácidos e ácidos graxos essenciais, cálcio, zinco, ferro e cobalamina. Pesquisas experimentais em humanos indicam que vegetarianos e não-vegetarianos apresentam capacidade aeróbica semelhante. em relação ao desempenho em atividades de força e potência muscular, as pesquisas são escassas, mas as existentes não apontam diferenças significativas. Situações de risco cardiovascular têm sido confirmadas, devido ao provável quadro de hiperhomocisteinemia, em decorrência da baixa ingestão de cobalamina. As dietas vegetarianas são isentas de creatina, o que resulta em estoques musculares mais baixos nessa população. Possivelmente ocorrem alterações hormonais e metabólicas em resposta às dietas vegetarianas, como baixos níveis de testosterona e androstenediona. A função imune parece não ser prejudicada. Dessa forma, a prática de dietas vegetarianas apresenta-se compatível com a prática esportiva cotidiana, desde que bem planejada para evitar deficiências nutricionais.

Lipid peroxidation and generation of hydrogen peroxide in frozen-thawed ram semen supplemented with catalase or Trolox

Semen manipulation and cryopreservation-thaw procedures may accelerate the generation of reactive oxygen species (ROS). Sperm exposure to large amounts of ROS has been shown to cause membrane lipid peroxidation and cellular injury to the sperm. The objective of this study was to overcome the ROS production in frozen-thawed ram semen by the addition of the antioxidants catalase or Trolox to semen following thawing. Frozen-thawed ram semen (100 x 10(6) sperm/straw) was supplemented with PBS (control group), 100 mu g/ml catalase, or 100 mu M Trolox/10(8) sperm (catalase and Trolox being dissolved in PBS) and incubated (37 degrees C) for 5 min. Under the experimental conditions used in this study, the catalase and Trolox antioxidants failed to protect the sperm from the spontaneous production of ROS. However, when lipid peroxidation was induced by iron (FeSO(4)), the addition of Trolox promoted a reduction (P < 0.05) in the formation of TBARS in the semen, compared to the control and catalase semen samples. The generation of TBARS and H(2)O(2) occurred in the extender alone, without the presence of sperm cells. In conclusion, the addition of Trolox to frozen-thawed ram semen could be beneficial as it decreases the production of TBARS when oxidative stress is induced. It is possible that a longer incubation period could lead to different results. The concentration of catalase also needs to be further evaluated. The extender could contribute to the oxidative stress of sperm, as it is a source of ROS during the cryopreservation of semen. (C) 2010 Elsevier B.V. All rights reserved.

Ovary peltate trichomes of Zeyheria montana (Bignoniaceae): Developmental ultrastructure and secretion in relation to function

center dot Background and Aims Nectar production in the Bignoniaceae species lacking a nectariferous functional disc is ascribed to trichomatic glands around the ovary base and/or on the inner corolla wall. Nevertheless, knowledge about the secretion and function of these glands is very incomplete. The purpose of this paper is to study, from a developmental viewpoint, the ultrastructure, histochemistry and secretory process of the peltate trichomes on the ovary of Zeyheria montana, a species in the Bignoniaceae which has a rudimentary disc.center dot Methods Samples of the gynoecium at various developmental stages were fixed and processed for light and electron microscopy. Histochemistry and cytochemistry tests were performed to examine the chemical composition of exudates. Thin layer chromatography was used to determine the presence of alkaloids and terpenes in gynoecium and fruit extracts, and in fresh nectar stored in the nectar chamber.center dot Key Results Peltate trichomes at different developmental stages appear side by side from floral budding up to pre-dispersal fruit. Large plastids with an extensive internal membrane system consisting of tubules filled with lipophilic material, abundant smooth endoplasmic reticulum, few Golgi bodies, lipophilic deposits in the smooth endoplasmic reticulum and mitochondria, and scattered cytoplasmic oil droplets are the main characteristics of mature head cells. The secretion which accumulates in the subcuticular space stains positively for hydrophilic and lipophilic substances, with lipids prevailing for fully peltate trichomes. Histochemistry and thin layer chromatography detected terpenes and alkaloids. Fehling's test to detect of sugars in the secretion was negative.center dot Conclusions the continuous presence and activity of peltate trichomes on the ovary of Z. montana from early budding through to flowering and fruiting set, and its main chemical components, alkaloids and terpenes, suggest that they serve a protective function and are not related to the floral nectar source or to improving nectar quality.

Dendroid colleters on vegetative and reproductive apices in Alibertia sessilis (Rubiaceae) differ in ultrastructure and secretion

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

The oleoresin secretory system in seedlings and adult plants of copaiba (Copaifera langsdorffii Desf., Leguminosae-Caesalpinioideae)

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

Healing, Antioxidant and Cytoprotective Properties of Indigofera truxillensis in Different Models of Gastric Ulcer in Rats

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

The Saccharomyces cerevisiae COQ10 gene encodes a START domain protein required for function of coenzyme Q in respiration

Deletion of the Saccharomyces cerevisiae gene YOL008W, here referred to as COQ10, elicits a respiratory defect as a result of the inability of the mutant to oxidize NADH and succinate. Both activities are restored by exogenous coenzyme Q(2). Respiration is also partially rescued by COQ2, COQ7, or COQ8/ABC1, when these genes are present in high copy. Unlike other coq mutants, all of which lack Q(6), the coq10 mutant has near normal amounts of Q(6) in mitochondria. Coq10p is widely distributed in bacteria and eukaryotes and is homologous to proteins of the aromatic-rich protein family Pfam03654 and to members of the START domain superfamily that have a hydrophobic tunnel implicated in binding lipophilic molecules such as cholesterol and polyketides. Analysis of coenzyme Q in polyhistidine-tagged Coq10p purified from mitochondria indicates the presence 0.032-0.034 mol of Q(6)/mol of protein. We propose that Coq10p is a Q(6)-binding protein and that in the coq10 mutant Q(6) it is not able to act as an electron carrier, possibly because of improper localization.