Bottom rounds were shipped to the Rosenthal Meat Science and Technology Center, ground and enhanced with one of the following predetermined treatments: control; 0.4% sodium phosphates and 0.3% salt; 0.25% sorghum bran; 2.0% sorghum bran; 0.25% sorghum bran, 0.4% sodium phosphates and 0.3% salt; and 2.0% sorghum bran, 0.4% sodium phosphates, and 0.3% salt. The ground beef was formed into 226 g ground beef patties, packaged in an 80% O2 and 20% CO2 gaseous environment, and stored under retail display at 4 degrees for 0, 3, 6, or 9d. Measurements to determine rate and extent of oxidation, rate of discoloration, and sensory characteristics were taken to evaluate the effectiveness of sorghum bran. Patties containing the highest amount of sorghum bran had the lowest TBARS values over 9 days of storage, lower a* values, greater amounts of discoloration, darker lean color, and less cook loss (P<0.05) than control patties. Patties enhanced with the highest level of sorghum bran had lower beefy/brothy and bloody flavor aromatics, higher sorghum flavor, more bitter and burnt aftertaste, and more sandy/gritty textures (P<0.05) when compared to control patties. Patties containing the low amount of sorghum had lower TBARS values (P<0.05), but similar amounts of cook loss as the control patties. Patties containing a low sorghum level, 0.4% sodium phosphates (SP) and 0.3% salt (S) had lower (P<0.05) amounts of cook loss when compared to control patties. Patties containing low amounts of sorghum were similar to control patties in terms of redness while the addition of low sorghum, SP, and S decreased (P<0.05) the degree of redness. Patties containing low amounts of sorghum bran had similar amounts of discoloration compared to control (CONT) patties. Also, these had less bloody flavor aromatics (P<0.05), but were similar in sorghum flavor aromatics and bitter taste when compared to control patties. The addition of sorghum bran at low levels can retard oxidative rancidity in ground beef patties without causing detrimental color changes and negatively affecting sensory attributes, while patties enhanced with 2% sorghum bran have extensive discoloration and undesirable sensory attributes.

Quercetin is a flavonoid found in commonly consumed fruits and vegetables that has exhibited powerful antioxidant and anti-inflammatory properties in rodents and in vitro. In humans, the ergogenic effects of antioxidant supplementation on exercise performance and adaptations are still equivocal and need to be further investigated. A powerful antioxidant such as quercetin may inhibit the high levels of oxidative stress associated with the high volume and intensity of exercise training seen with trained individuals. There have been equivocal findings thus far regarding the ergogenic effect of either acute or chronic supplementation of quercetin on exercise performance. PURPOSE: To determine the effect of 28 days of daily quercetin supplementation on cycling time trial performance and the associated exercise performance variables. METHODS: Thirteen trained cyclists (VO2peak 58.8 ± 3.9 ml/kg/min) were recruited for this study from the University of Texas at Austin and the local Austin, Texas community and participated in this placebo controlled, randomized, crossover designed study. After initial assessment of baseline data (VO2peak, lactate threshold, and two familiarization time trials), participants began daily supplementation of either an antioxidant supplement containing vitamins and quercetin (Q-VIT: 1000mg quercetin, 820mg Vitamin C, 40mg Vitamin B3) or the same vitamin supplement without quercetin (VIT: 820mg Vitamin C, 40mg Vitamin B3). A simulated time trial using an electromagnetically braked cycle ergometer in which subjects had to complete a set amount of work (kJ) as fast as possible was performed on the last day of supplementation. Measured performance variables included: time to completion, average power output, average oxygen consumption (VO2), Respiratory Exchange Ratio (RER), gross mechanical efficiency (GE), heart rate (HR), and rating of perceived exertion (RPE). RESULTS: Quercetin had no effect on HR, RER, power output, or RPE. There was also no difference in time to complete the time trial between treatments. However, an approximately ~2% higher, but not significantly different, VO2 during Q-VIT supplementation significantly lowered the GE compared to VIT (Q-VIT: 20.49 ± 0.26 % and 19.94 ± 0.33 %; VIT: 20.9 ± 0.24 % and 20.37 ± 0.33 %; p < .01) at 15 and 30 min respectively. CONCLUSION: Chronic supplementation for 28 days with a quercetin based antioxidant supplement lowered cycling gross efficiency in well trained cyclists, but it did not affect performance time. The results of the current study suggest that chronic supplementation with quercetin does not influence aerobic exercise performance in well trained athletes. / text

The role of antioxidants in cancer has been controversial for a long time. Although the public’s belief is that antioxidants prevent and/or inhibit cancer, there is increasing evidence to suggest the opposite: that cancer cells require antioxidants to survive. We wanted to interrogate the role of antioxidants in cancer by investigating both upstream regulators and downstream effectors of antioxidant signaling. We have identified protein tyrosine phosphatase non-receptor type 12 (PTPN12) as a novel regulator of antioxidant signaling in cancer. PTPN12 reduces reactive oxygen species (ROS) levels by promoting activity of the forkhead box O (FOXO) family of antioxidant transcription factors. We have also elucidated the impact of glutathione (GSH), the most abundant antioxidant in the cell, on tumorigenesis. We have found that GSH is required for cancer initiation, yet dispensable once transformation has occurred due to compensation provided by the thioredoxin (TXN) antioxidant pathway. Together, these studies expand our knowledge of the role of antioxidants in cancer and provide numerous avenues of research for the future.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references. Also available via the Internet.

Orientador: Dulce Helena Siqueira Silva / Banca: Lourdes Campaner dos Santos / Banca: Edilberto Rocha Silveira / Banca: Valdir Cechinel Filho / Banca: Mary Ann Foglio / Resumo: A criação de um modelo nacional de saúde pautado nas aptidões e carências brasileiras é tida como fundamental para tornar o acesso à saúde pública mais abrangente e de melhor qualidade. O histórico do desenvolvimento mundial de medicamentos, a biodiversidade e os conhecimentos tradicionais associados a esta, e as competências científicas existentes no Brasil evidenciam a importância da bioprospecção. O gênero Lippia é amplamente empregado em etnomedicina e é constituído principalmente por espécies aromáticas. As investigações químicas e farmacológicas estão majoritariamente concentradas nos seus óleos essenciais, mas alguns componentes fixos, como flavonóides, fenilpropanóides, naftoquinóides e iridóides glicosilados já foram relatados. O Brasil abriga a maioria das espécies deste gênero, mas diversos problemas taxonômicos dificultam o estabelecimento de dados precisos. O stress oxidativo é apontado como ponto central no desenvolvimento de processos degenerativos associados ao envelhecimento e a diversas doenças. Conseqüentemente, terapias antioxidantes estão sendo propostas para o seu tratamento ou prevenção. Este trabalho descreve o fracionamento de extratos de folhas e de ramos de L. salviaefolia guiado por testes antioxidantes que levou ao isolamento de 16 substâncias fenólicas, sendo 4 isômeros interconversíveis inéditos, 2S e 2R-3',4',5,6-tetraidroxi-7-O-β-glicopiranosil-flavanona (12a e 12b) e 2S e 2R-5,8,3',4'-tetraidroxi-7-O-β-glicopiranosil-flavanona (13a e 13b), que foram identificadas em mistura por estudos extensivos de Ressonância Magnética Nuclear e Espectrometria de Massas. Foram isoladas também 8 substâncias do extrato de raízes de L. lupulina, selecionado com base em estudos iniciais de desreplicação por Cromatografia Líquida de Alta Eficiência acoplada a Arranjo de Fotodiodos (CLAE-DAD). Os extratos... (resumo completo, clicar acesso eletrônico abaixo) / Abstract: The creation of a national model of health guided by need and capacity in Brazil is seen as fundamental to making access to public health more comprehensive and of better quality. The historical development of world medicine, the biodiversity and traditional knowledge associated with this, and the scientific expertise available in Brazil highlight the significance of bioprospecting in this country. The genus Lippia is widely used in ethnomedicine. Since most of its species are aromatic, the studies on the chemistry and pharmacology of this genus are mainly focused in essential oils, but some fix compounds, such as flavonoids, phenylpropanoids, naphthoquinoids and iridoids glucosides have also been reported. It is estimated that Brazil hosts most of Lippia species, but several taxonomical problems related to this species hamper the establishment of accurate data difficult. Oxidative stress has a central role in the development of degenerative processes associated to aging and several diseases, including cancer and inflammation. Consequently, antioxidant therapies are being proposed for their treatment or prevention. This work describes the fractionation procedures of L. salviaefolia leaves and stems extracts guided by simple antioxidant assays which led to 16 phenolic compounds, including 4 novel interconverting isomers (2S) and (2R)-3',4',5,6-tetrahydroxyflavanone-7-O-β-glucopyranoside (12a and 12b) and (2S) and (2R)-3',4',5,8-tetrahydroxyflavanone-7-O-β-glucopyranoside (13a and 13b), which were identified in mixture by extensive use of 1D and 2D NMR and MS techniques. Additionaly, other 8 compounds were isolated from the extract of roots of L. lupulina, which led to its selection for dereplication studies by High Pressure Liquid Chromatography-Photodiode Array Detector (HPLC-DAD). The bioactivity evaluation of extracts and isolated compounds from L. salviaefolia was initiated... (Complete abstract click electronic access below) / Doutor

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Made available in DSpace on 2016-08-29T15:38:47Z (GMT). No. of bitstreams: 1 tese_8485_DAMASCENO JPL- 2016 - Dissertação de mestrado - Estudo de solubilidade e das atividades antioxida.pdf: 2214333 bytes, checksum: cee189be1a37b594fdc4f8ef753ccb16 (MD5) Previous issue date: 2016-03-24 / Helicobacter pylori é uma bactéria Gram-negativa que infecta a mucosa do estômago levando ao surgimento de patologias, tais como gastrite, úlceras pépticas e câncer de estômago, sendo de difícil erradicação. O tratamento padrão nem sempre é bem sucedido em função de efeitos colaterais, altos custos e baixa adesão por parte do paciente, levando a necessidade da busca por novas moléculas mais efetivas contra este microrganismo. Neste contexto, a isocumarina paepalantina, 9,10-diidroxi-5,7-dimetoxi-1H-nafto(2,3c)-piran-1-ona, isolada dos capítulos de Paepalanthus bromelioides, Eriocaulaceae, tem demonstrado em estudos anteriores uma ampla variedade de atividades biológicas como antibacteriana, antioxidante, anti-inflamatória e citotóxica, dos quais se destacam a capacidade antimicrobiana e antioxidante, abrindo portas para a avaliação de seus efeitos sobre a infecção causada por H. pylori e modulação das espécies reativas de oxigênio (EROs) e espécies reativas de nitrogênio (ERNs) geradas neste processo. Como é uma molécula pouco estudada, ainda carece de dados sobre sua solubilidade a fim de se encontrar uma alternativa viável ao uso do DMSO considerando a toxicidade do mesmo em cultura celular e sua interferência em testes de atividade antioxidante. Dessa forma, o objetivo deste trabalho foi avaliar solventes como alternativas ao uso do DMSO, com validação de metodologia analítica espectrofotométrica própria, a fim de escolher um veículo adequado para ensaios de atividade antioxidante frente a radicais sintéticos (DPPH e ABTS) e espécies reativas de oxigênio (HOCl, OH&#9679;, O2-&#9679;, H2O2) e nitrogênio (NO&#9679;) e de atividade anti-H. pylori. Entre os solventes avaliados, propilenoglicol em pH 7,5 foi o solvente de escolha, sendo que os resultados sugerem uma menor interferência nos ensaios se comparado ao DMSO, tornando uma alternativa viável do ponto de vista tecnológico. Os resultados apontam uma forte atividade antioxidante da paepalantina, comparável ao Trolox®. Também foi observado um importante efeito sobre a cultura de H. pylori com CIM de 128 &#956;g/ml e CBM de 256 &#956;g/ml e sinergismo de sua sub-MIC com os antibióticos amoxicilina e metronidazol demonstrando possivelmente atuar sobre a permeabilidade da membrana bacteriana e por inibição das Penicillin-Bindind Proteins (PBPs), devido as alterações morfológicas observadas em H. pylori por microscopia eletrônica de varredura, tornando a paepalantina promissora para o desenvolvimento futuro de medicamento para o combate de H. pylori e seus males associados.

Aldehydic lipid peroxidation products, free radical mediated oxidative stress and antioxidant status were investigated in three in vitro plant systems with the objective of exploring the involvement of oxidative stress in plant tissue cultures. <i>Daucus carota</i> was used as a model system for the study of somatic embryogenesis and for the development of an enzyme linked immunosorbant assay (ELISA) technique, for the detection of hydroxynonenal-protein adducts in plant extracts. This study shows for the first time, in plants, that exogenously applied lipid peroxidation products hydroxynonenal (HNE) and malondialdehyde (MDA) inhibit callus proliferation and development (as somatic embryogenesis). Removal of the aldehydes led to a reversal of inhibitory effects. For the first time, HNE and MDA were measured in extracts of callus generated from different explants of <i>Ipomoea batatas</i> (an economically significant crop species). Using ELISA, HNE-protein adducts have been detected, in extracts from all three cultivars of I. batatas tested. Increases in the activities of the antioxidants, catalase and peroxidase were also observed in nodes of <i>I. batatas</i> after transfer to callus induction medium. Three callus cultures of <i>Glycine max</i>, one of which was habituated against benzylamino purine, the second contained chlorophyll (green) and the third, devoid of chlorophyll (white) were profiled for lipid peroxidation products and antioxidant activity. This is first report of the detection free HNE and MDA in <i>G. max</i> and were detected in all three callus types, with the highest concentrations for both aldehydes in the habituated callus line. HNE-protein adducts were only detected in the white callus line of <i>G. max</i>. The level of hydroxyl radical activity was found to be increased in aged callus compared to callus taken from the mid-point of the subculture cycle. Low activities of catalase, peroxidase and other antioxidants were found in the habituated callus. It is proposed that increased amounts of hydroxyl radicals, high levels of HNE and MDA and the low activity of antioxidants leads to oxidative stress in extreme conditions such as habituation in <i>in vitro </i>plant systems. This study has implications regarding the understanding of <i>in vitro</i> plant recalcitrance.

Background: Currently, gastric cancer (GC) is considered a public health problem worldwide. Using medicinal plants for the prevention of chronic diseases such as cancer constitutes new alternatives in traditional medicine. Oenothera rosea (OR) could be an option, but it needs to be evaluated. Aim: The main objective of this study was to evaluate the protective effect of OR extract on N-methyl-N-nitrosourea (NMU)-induced GC in rats. Methods: In total, 80 male Holtzman rats were randomized into five groups. Group A received the saline solution (5mL/kg), group B received NMU 500 μg/kg (cancer inductor) by oral administration for 16 weeks, and groups C, D, and E were treated with OR extract (100, 200, and 300 mg/kg, respectively) and NMU in order to evaluate the preventive effect on cancer induced by NMU for 16 weeks. Blood and histological samples of stomachs were collected to determine histopathological, biochemical, and hematological parameters between different experimental groups. Results: Groups C, D, and E presented less histopathological changes such as anaplastic and hyperplastic cells, compared with group B. Hematological and biochemical parameters were recorded, and superoxide dismutase, malondialdehyde, and nitric oxide levels were statistically less than those of NMU group (P<0.05, P<0.01, and P<0.01). Conclusion: Considering the histopathological signs and the antioxidant activity in vivo as well as hematological and biochemical parameters of ethanolic extract of OR, we concluded that its administration in rats has a protective effect on GC, which is induced experimentally. This species could be studied in clinical trials for patients with GC in the future.

Combretum species are used in many cultures in folk medicine for treatment of microbial infections and several inflammatory conditions (abdominal pains, headache and toothache). There are two possible mechanisms to explain the use of plants extracts to treat microbial infections. A direct effect involves the action of active agents in the extracts on the microorganism tested and the indirect effect involves the stimulation of the host immune system to overcome the effects of microorganisms via the host immune system. Traditional healers use mainly aqueous extracts and in all Combretaceae we have studied, these extracts had hardly any in vitro antibacterial activity. A search of the literature confirmed our observations, aqueous plants extracts of many plant species usually have very little direct in vitro antimicrobial activity. One would expect that aqueous extracts would have higher anti-oxidant activities and may stimulate the immune system of patients thereby combating the infection indirectly. This possibility prompted the investigation of the antioxidant potential of more polar extracts of Combretum species. Methanol extracts of leaves of ten different Combretum species were evaluated for qualitative antioxidant activity by spraying TLC chromatograms of leaf extracts with 2, 2-diphenyl-1-picrylhydrazyl (DPPH). Compounds with anti-oxidant activity bleached the purple colour. Leaf extracts of Combretum apiculatum subspp apiculatumhad the most antioxidant compounds. This species was consequently selected for further examination. Anti-oxidant directed fractionation of the leaf extracts of C. apiculatum led to the isolation of four antioxidant compounds from ethyl acetate and butanol soluble fractions. The structures of the compounds were determined by spectral analyses (1H-NMR, 13C-NMR and MS) and identified as cardamomin (1), pinocembrin (2), quercetrin (3) and kaempferol (4). These compounds occur commonly in plant extracts, but the anti-oxidant activities of all these compounds were not known previously. In a quantitative antioxidant assay using DPPH with L-ascorbic acid as positive control, the more polar fractions (ethyl acetate and butanol) obtained by solvent-solvent fractionation had the highest activity among the extracts with EC50 values of 3.91 ± 0.02 and 2.44 ± 0.02 µg/mL respectively. Of the isolated compounds, quercetrin (3) and kaempferol (4) had strong antioxidant activity with EC50 values of 11.81 ± 85 and 47.36 ± 0.03 µM respectively. Cardamomin (1) and pinocembrin (2) did not have strong activity as these compounds could not scavenge 50% of the DPPH radical at the highest concentration (200 µM) tested. L-ascorbic acid was used standard antioxidant agent (EC50 = 13.37 ± 0.20 µM or 2.35 µg/mL). The antioxidant activity of the isolated compounds supported structure-activity relationships developed by other authors. The cytotoxicity of cardimonin and pinocembrim was evaluated using MTT assay with, berberine as positive control and DMSO as negative control. At higher concentrations than 50 µg/ml of cardimomin or pinocembrin the cells were not viable. Cardimomin was more toxic to the cells (LC50 of 1.97 µg/ml) than pinocembrin (LC50 of 29.47 µg/ml) and even the positive control, berberine (LC50 of 12.35 µg/ml). The presence of these antioxidants could provide a rationale for the ethnomedicinal use of this species for the treatment of inflammatory conditions in traditional medicine. It appears that the antimicrobial activity of aqueous plant extracts may be related to the antioxidant activity leading to a stimulated immune system rather than antimicrobial activity per se Because the crude polar extract had an antioxidant activity half that of L ascorbic acid, the rationale for using these plants by traditional healers becomes clear. The toxicity of cardomomin is a warning that the safety of these extracts should be evaluated in in vivo assays. / Dissertation (MSc (Veterinary Science))--University of Pretoria, 2007. / Paraclinical Sciences / unrestricted