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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Application of dietary b-1,3-glucan in enhancing resistance of Penaeus monodon against vibrio and viral infections

Chang, Cheng-Fang 17 July 2000 (has links)
Three series of studies were conducted to quantify the effectiveness of dietary incorporation of b-1,3-glucan (BG) from Schizophyllum commune in enhancing the immunity and resistance of grass prawn Penaeus monodon to vibriosis and white spot syndrome virus (WSSV) infections. In the first series of studies, three experiments were conducted to evaluate the effectiveness of dietary b-1,3-glucan on shrimp growth and resistance to vibriosis. Weight gain, survival and feed efficiency of juvenile shrimp (0.5 ¡Ó 0.1 g) were not significantly different (P>0.05) after being fed the diets containing BG 0, 0.2, 2, 10 g/kg diet for 18 weeks. Subadult shrimp (20.4 ¡Ó 2.1 g) fed the diet containing of BG 2 g/kg diet for 10 days showed a significantly (P<0.001) enhanced resistance against vibriosis. Postlarvae fed with the BG diet (2 g/kg diet) were more resistant (P<0.001) against starvation and V. harveyi challenges than the postlarvae fed non-BG diet. Additive disease resistance was observed when polyphosphorylated L-ascorbic acid (PAA) was used together with BG. In challenge tests with V. damsela, shrimp fed with PAA (0.2 g/kg diet) + BG (2 g/kg diet) diet for 20 days had a survival rate up to 60%. In the second series of studies, two experiments were conducted to evaluate the effectiveness of dietary b-1,3-glucan on wound healing and immunity in spawners. Dietary supplement of BG reduced the chance of infections, but did not help wound healing as did the supplement of PAA. And regardless of indoor or outdoor rearing, the survival rate of brooder (135 ¡Ó 25 g) fed the BG (2 g/kg diet) diet was higher (P<0.001) than that of the non-BG group. Fed the BG brooders showed enhanced haemocyte phagocytic activity, cell adhesion and superoxide anion production then the control group. Third series of studies evaluated the effectiveness against white spot syndrome virus (WSSV). Six days after being challenged with WSSV, 12.2 % of the BG-treated (2 g/kg diet for 15 days) postlarvae (PL15) and 20 % BG-treated (2 g/kg diet for 20 days) juveniles (5.5 ¡Ó 0.5 g) were still alive; while all non-BG-treated shrimp died. In order to quantify the effectiveness of BG to WSSV, juveniles (6.5 ¡Ó 0.4 g) were fed diets containing graded levels of BG. The results showed that shrimp fed the diet containing BG 10 g/kg for 20 days had the highest (P<0.001) survival rate (42 %) among all groups. Shrimp that received diets supplemented with BG at a dosage >2 g/kg recuperated 9 ~ 12 days after WSSV challenge; while the group fed diets with no or 1 g/kg BG suffered from rapid decrease in total haemocyte count, phagocytic activity, phenoloxidase, O2-, superoxide dismutase (SOD) production and subsequent high mortality. The results in this study showed that b-1,3-glucan is effective in enhancing the phagocytic activity, phenoloxidase, O2- and SOD productions and consequently the resistance of postlarval, juvenile, subadult and brooder P. monodon against vibriosis and viral infections. Since prolonged use of BG, even at optimal dietary levels, decreased the immunity of the shrimp, care therefore must be taken to maximize its effectiveness. A cycle of dietary BG supplement of 2 ~ 10 g/kg diet for 20 days with an intermission of 10 days may serve the purposes.
22

Cyanocobalamin is a Superoxide Scavenger and Neuroprotectant in Neuronal Cells

Chan, Wesley 04 1900 (has links)
Les dommages au nerf optique (neuropathie optique) peuvent entraîner la perte permanente de la vision ou la cécité causée par la mort des cellules ganglionnaires de la rétine (CGR). Nous avons identifié qu’une surproduction de l'anion superoxyde constitue un événement moléculaire critique précédant la mort cellulaire induite par des lésions. Récemment, Suarez-Moreira et al (JACS 131:15078, 2009) ont démontré que la vitamine B12 peut capter l’anion superoxyde aussi efficacement que l’enzyme superoxyde dismutase. La carence en vitamine B12 peut conduire à une neuropathie optique causée par des mécanismes inconnus. Nous avons étudié la relation entre la captation de superoxyde par la cyanocobalamine (forme de vitamine B12 la plus abondante) et ses propriétés neuroprotectrices dans les cellules neuronales. La cyanocobalamine aux concentrations de 10 μM et 100 μM a réduit le taux de production de superoxyde respectivement par 34% et 79% dans les essais sans-cellule. Dans les cellules RGC-5 traités avec la ménadione, les concentrations de cyanocobalamine supérieures à 10 nM ont diminué l’anion superoxyde à des valeurs similaires à celles traitées par PEG-SOD. La cyanocobalamine aux concentrations de 100 μM et 1 μM a réduit la mort des cellules RGC-5 exposées à la ménadione par 20% et 32%, respectivement. Chez les rats avec section du nerf optique unilatérale, une dose intravitréenne de 667 μM de cyanocobalamine a réduit le nombre de CGRs exposées au superoxyde. Cette dose a également augmenté le taux de survie des CGRs comparativement aux rats injectés avec la solution témoin. Ces données suggèrent que la vitamine B12 peut être un neuroprotecteur important, et sa carence nutritionnelle pourrait causer la mort de CGRs. La vitamine B12 pourrait aussi potentiellement être utilisée comme une thérapie pour ralentir la progression de la mort CGR chez les patients avec les neuropathies optiques caractérisés par une surproduction de superoxyde. / Damage to the optic nerve (optic neuropathy) can result in permanent loss of vision or blindness through retinal ganglion cell (RGC) death. Our prior work identified a burst of superoxide anion as a critical molecular event in RGCs prior to injury-induced cell death. Recently, Suarez-Moreira et al (JACS 131:15078, 2009) demonstrated that vitamin B12 scavenges superoxide as effectively as superoxide dismutase. Vitamin B12 deficiency can lead to optic neuropathy through unknown mechanisms. We investigated the relationship between superoxide scavenging by cyanocobalamin, the most abundant vitamin B12¬¬ vitamer, and its neuroprotective properties in neuronal cells. Cyanocobalamin at concentrations of 10 μM and 100 μM reduced the rate of superoxide generation by 34% and 79% in cell free assays, respectively. In menadione-treated RGC-5 cells, cyanocobalamin concentrations above 10 nM scavenged superoxide anion similar to those treated with pegylated-SOD. Cyanocobalamin at concentrations of 100 μM and 1 mM reduced RGC-5 cell death from menadione by 20% and 32%, respectively. In rats with unilateral optic nerve transection, a single intravitreal dose of 667 μM cyanocobalamin significantly reduced the number of RGCs with superoxide. This dose also increased RGC survival rate compared to rats injected with saline control. These data suggest that vitamin B¬¬12 may be an important neuroprotectant, which could cause death of RGCs when depleted in nutritional deficiency. Vitamin B12 could also potentially be used as a therapy to slow progression of RGC death in patients with optic neuropathies characterized by overproduction of superoxide.
23

Efeito de difenóis sobre alguns processos oxidativos / Effects of diphenols on oxidative processes

Ohara Augusto 27 November 1975 (has links)
Catecol e catecolaminas foram ensaiados sobre as atividades NADPH e NADH oxidásica dos microssomos. Quantidades catalíticas de adrenalina aumentam de duas a três vezes a velocidade de oxidação do NADPH, após um pequeno período de indução. O efeito da adrenalina é suprimido pela superóxido dismutase, se a enzima é adicionada antes de iniciada a reação. O efeito catalítico é atribuído a dois produtos de oxidação da adrenalina pelo íon superóxido; à quinona, produto de oxidação de dois elétrons e ao adrenocromo, produto de oxidação de quatro elétrons. Provavelmente, o adrenocromo reoxida a NADPH citocromo c redutase, e a quinona formada reage com oxigênio, regenerando adrenocromo. A adrenalina não mostrou qualquer efeito sobre a atividade NADH oxidásica, nem sobre a atividade NADPH oxidásica, estimulada por menadiona. Provavelmente, durante estes processos, dois elétrons são transferidos simultaneamente ao oxigênio. Catecol e catecolaminas duplicam a velocidade de oxidação do NADH em presença de quantidades catalíticas de NADH-citocromo b5 redutase e citocromo b5. Este resultado sugere a formação do íon superóxido, durante a autoxidação do citocromo b5. Catecol e p-hidroquinona promovem, cataliticamente, a oxidação da oxihemoglobina e oximioglobina à forma ferri. A velocidade de oxidação da oxihemoglobina mostra dependência de primeira ordem em relação à concentração de hemeproteína e de meia ordem em relação ao difenol ; contudo a altas concentrações dos catalisadores observa-se saturação, com valores de Vmáx similares para ambos os difenóis. É proposto que uma quinona , inicialmente formada, oxida a oxihemeproteína com liberação de oxigênio; por sua vez, a semiquinona oxida uma segunda molécula de oxihemeproteína, sendo que o oxigênio ligado recebe dois elétrons. Exceto para o caso da oximioglobina, que é mais reativa, a forma reduzida do catalisador deve estar presente para se opor ao desaparecimento da semiquinona por dismutação. Desde que se observa a liberação de oxigênio, esperada para a formação de água, o sistema pode ser considerado modelo de oxidase terminal. Infere-se tentativamente, que a oxihemoglobina tem estrutura HbFe2+ ...O2, e que a velocidade da oxidação catalisada é limitada pela velocidade de produção da verdadeira forma reativa, a estrutura ferri-superóxido, HbFe3+...O-2. / Catechol and catecholamines have been assayed upon the microsomal NADPH and NADH oxidase activities. Adrenaline shows a catalytic effect on the NADPH oxidation characterized by a small lag. The two-to three fold increase in rate can be supressed by dismutase if the enzyme is added before superoxide the reaction begins. The catalytic effect is ascribed to two products of adrenaline oxidation by the superoxide ion; to the quinone, the two electron oxidation product, and to the adrenochrome, the four electron oxidation product. Presumably, the adrenochrome reoxidizes the NADPH-cytochrome c reductase, and the formed quinone reacts with oxygen and regenerates the adrenochrome. Adrenaline neither changed, the NADH oxidase activity nor the menadione-stimulated NADPH oxidase activity. Presumably in these processes, two electrons are simultaneously transferred to the oxygen. Catechol and catecholamines doubled the rate of autoxidation of NADH in the presence of catalytic amounts of NADH-cytochrome b5 reductase and cytochrome b5 This result suggests superoxide ion formation in the autoxidation of the cytochrome. Catechol and p-hydroquinone catalytically promote the oxidation of oxyhemoglobin and oxymyoglobin to the ferri-form. Kinetic data for oxyhemoglobin oxidation indicates a first-order dependence upon the hemoprotein concentration and half-order dependence upon diphenol; however at high catalyst concentration, saturation is observed with similar Vmax values for both diphenols despite the difference in reactivity. It is proposed that initially formed quinone oxidizes the hemoprotein with oxygen release; in turn the semiquinone oxidizes a second molecule of hemoprotein and regenerates the quinone, with the bound oxygen acquiring two electrons. Except for the more reactive oxymyoglobin, the reduced form of the catalyst must be present to oppose semiquinone disappearance by dismutation, Since the expected release of 02 for water formation is observed, the system may be considered a model for terminal oxidase. It is tentatively inferred that oxyhemoglobin has the structure HbFe2+...02 and that the rate of the catalyzed oxidation is limited by the rate of generation of the true reacting form, the superoxide ferri structure, HbFe3+...0-2.
24

Rôle de la sérotonine et de la connexine 43 dans la paroi artérielle pulmonaire : implications dans l'hypertension pulmonaire / Role of serotonin and connexin 43 in the pulmonary arterial wall : implications in pulmonary hypertension

Khoyrattee, Nafiisha 12 December 2014 (has links)
Au niveau des artères intrapulmonaires (AIP) de rats sains, la connexine 43 (Cx43) située au niveau de la jonction myoendothéliale (JME) intervient dans la réactivité à la 5-HT. La 5-HT produit de l’anion superoxyde (O2•) au niveau du muscle lisse et du monoxyde d’azote (NO) au niveau de l’endothélium des AIP. La Cx43 permet alors le passage de l’O2• du muscle lisse vers l’endothélium de façon à diminuer la biodisponibilité du NO et maintenir une contraction physiologique de l’artère pulmonaire. Cependant, l’augmentation d’O2• par d’autres agonistes vasoconstricteurs tels que l’endothéline-1 (ET-1) et la phényléphrine (PHE) et les mécanismes impliqués dans cette augmentation restent encore méconnus dans la circulation pulmonaire. Ainsi, ce travail vise à identifier les agonistes qui provoquent une augmentation de la quantité d’O2• et à mettre en évidence les voies de signalisation mises en jeu au niveau des AIP de rats. Par ailleurs, la Cx43 étant impliquée dans la réactivité des AIP de rats sains à la 5-HT, le rôle de la Cx43 dans la circulation pulmonaire pathologique a été étudié à l’aide d’un modèle de souris hétérozygote pour la Cx43 (souris Cx43+/-) souffrant d’hypertension pulmonaire (HTP) hypoxique chronique (HC). Nous avons montré que l’augmentation d’O2•au niveau des AIP est un mécanisme exclusif de la 5-HT. Cette augmentation provient uniquement d’une augmentation de production par la mitochondrie et les NADPH oxydases via un mécanisme de « ROS-induced ROS release » dépendant de la PKC. La 5-HT agit par le biais des récepteurs 5-HT2A, induit un influx calcique extracellulaire qui augmente la concentration calcique mitochondriale provoquant une augmentation de production d’O2• par le complexe I de la chaîne respiratoire mitochondriale. De plus, cette voie s’exerce au sein des microdomaines de signalisation, notamment les cavéoles. D’autre part, chez les souris Cx43+/- HTP HC le remodelage des AIPest inhibé et l’hypertrophie ventriculaire droite est freinée. La vasoréactivité des AIP à la 5-HT, à l’ET-1 et à la PHE est modifiée chez les souris Cx43+/- saines et HTP HC par rapport aux souris sauvages. Ces données apportent (1) des éléments de compréhension sur les voies de signalisation mises en jeu dans la production d’O2• en réponse à la 5-HT dans la circulation pulmonaire de rats sains et (2) de connaissances nouvelles sur le rôle de la Cx43 dans les AIP de souris saines et souffrant d’HTP HC. / Under physiological conditions, in rat intrapulmonary arteries (IPA), connexin 43 (Cx43) localised at the myoendothelial junctions is involved in the reactivity to serotonin (5-HT). 5-HT increases superoxide anion (O2•) in the smooth muscle and nitric oxide (a vasodilator) in the endothelium. O2• will then rapidly pass through Cx43 to scavenge endothelial NO to decrease the bioavailability of the latter and hence maintain IPA contraction in physiological conditions. However, to date, the increase in O2• level by other contractile agonists such as endothelin-1 (ET-1) and phenylephrine (PHE) and the mechanism involved in this increase are still unknown in the pulmonary circulation. The goal of this present work is to identify the contractile agonists involved in the increase of O2• and to highlight the signaling pathways involved in the agonists-induced increase of O2•. As Cx43 plays an important role in IPA contractile reactivity to 5-HT in healthy rats, the role of Cx43 under pathological conditions of the pulmonary circulation has been studied with a mice model heterozygous for Cx43 (Cx43+/-) suffering from hypoxic pulmonary hypertension (HPH). We have shown that O2• increase in rat IPA is exclusive to 5-HT. 5-HT-induced O2• increase in rat IPA is only from an increase in production by the mitochondria and NADPH oxydase via a ROS-induced ROS release mechanism dependent on PKC. Upon binding to 5-HT2A receptors, 5-HT induces an extracellular calcium influx which is responsible for an increase in mitochondrial calcium level and causes an upregulation in O2• production by the complex I of the mitochondrial respiratory chain. Moreover, this signaling pathway takes place in specialized microdomains, namely caveolae. On the other hand, interestingly, in Cx43+/- HPH mice, IPA remodeling is inhibited and right ventricular hypertrophy is less intense. IPA vasoreactivity to 5-HT, ET-1 and PHE is modified in Cx43+/- healthy and HPH mice as compared to wild type mice. These data bring (1) new elements of comprehension in the signaling pathways involved in 5-HT-induced O2• production in healthy rat pulmonary circulation and (2) new insights on the role of Cx43 in mice IPA under physiological and HPH conditions.
25

Modulation de l’activité du flavocytochrome b₅₅₈ : étude fonctionnelle / Modulating the activity of flavocytochrome b₅₅₈ : functional study

Souabni, Hager 06 March 2014 (has links)
Le complexe NADPH oxydase est un élément essentiel de l’immunité inné. Présent dans les cellules phagocytaires (neutrophile), sa fonction est de produire massivement, dans le phagosome, des anions superoxyde et générer ainsi des espèces encore plus réactives de l’oxygène qui vont détruire acides nucléiques, lipides et protéines des bactéries phagocytées. Le cœur membranaire catalytique du complexe NADPH oxydase est constitué d’un hétérodimère membranaire, le cytochrome b₅₅₈ (Cyt b₅₅₈). Après activation de celui-ci par les partenaires protéiques cytosoliques p47phox, p67phox, p40phox et Rac, une succession de réactions de transferts d’électron de part et d’autre de la membrane a lieu au sein du Cyt b₅₅₈ pour aboutir à la réduction du dioxygène de manière très contrôlée. Afin de mieux comprendre cette régulation, nous nous sommes d’abord intéressés aux stéreoisomères trans de l’acide arachidonique, activateur naturel de cet enzyme (cis), sur le fonctionnement de la NADPH oxydase et avons abordé cette étude parallèlement sur du Cytb₅₅₈ d’origine bovine présent dans des membranes de neutrophiles et dans des membranes de levures exprimant le Cytb₅₅₈ de manière hétérologue. Nous avons montré que la géométrie joue un rôle important sur l’activation du complexe enzymatique. Dans un deuxième temps, afin d’étudier le rôle de l’environnement membranaire sur le fonctionnement de la NADPH oxydase, nous avons déterminé les propriétés cinétiques et thermodynamiques de l’activité NADPH oxydase du Cytb₅₅₈ recombinant exprimé en levures, purifié, puis reconstitué en liposomes de composition lipidique variée. Après comparaison avec ces mêmes propriétés obtenues pour le Cytb₅₅₈ dans les membranes plasmiques et du réticulum endoplasmique de levures, nous avons montré que l’activité NADPH oxydase très sensible à la température peut être modulée par la composition et l’état physique de la membrane. / NADPH oxidase complex is a major actor of both antimicrobial host defense and inflammation by generating highly regulated superoxide anion, rapidly converted into reactive oxygen species (ROS). The NADPH oxidase complex consists of a heterodimeric integral membrane flavocytochrome b₅₅₈ and three cytosolic components p67phox, p47phox and p40phox, and the small GTP binding protein Rac. In response to a cellular stimulus, cytosolic proteins are recruited to the phagosomal membrane where they are assembled with the Cytb₅₅₈ to form the active NADPH oxidase. The aim of the work was to better understand the modulation of superoxide anion production by this enzyme. For this purpose, we performed experiments with both bovine neutrophil membranes and yeast membranes expressing the bovine recombinant Cytb₅₅₈. We first investigated the effect of the trans-isomerization of the cis-arachidonic acid, the activator of NADPH oxidase in vitro and showed that specific geometry of the activator plays an important role in the activation of the complex. We also studied the role of the membrane environment on the functioning of NADPH oxidase and determined the kinetics and thermodynamics of NADPH oxidase activity depending on the lipid composition of Cytb₅₅₈ proteoliposomes. Comparison with these properties obtained with recombinant Cytb₅₅₈ embedded into endoplasmic reticulum and plasma membranes, we showed that the NADPH oxidase activity is highly temperature dependent and can be modulated by the lipid environment and the physic state of the membrane.
26

Funkcionalne i antioksidativne osobine tropa cvekle (Beta vulgaris) / Functional and antioxidant characteristics of beetroot pomace (Beta vulgaris)

Vulić Jelena 04 September 2012 (has links)
<p>Etanolni ekstrakti tropa odabranih sorti cvekle (Detroit, Cardeal-F1, Egipatska, Bikor i Kestrel) preči&scaron;ćeni su primenom ekstrakcije na čvrstoj fazi (SPE). Sadržaj ukupnih<br />fenolnih jedinjenja, flavonoida i betalaina u preči&scaron;ćenim ekstraktima određeni su spektrofotometrijskim metodama. HPLC analizom utvrđen je kvalitativni i kvantitativni sastav fenolnih jedinjenja i betalaina ekstrakata tropa odabranih sorti cvekle. ESR spektroskopijom ispitana je antiradikalska aktivnost ekstrakata topa cvekle na stabilne DPPH i reaktivne superoksid anjon i hidroksil radikale.<br />Spektrofotometrijski je određena antioksidativna aktivnost na DPPH radikale i redukciona sposobnost po Oyaizu u ekstraktima odabranih sorti cvekle. Ispitana je in vitro<br />antiproliferativna aktivnost frakcija ekstrakata, njihovim delovanjem na rast tri histolo&scaron;ki različite humane ćelijske linije: MCF-7 (adenokarcinom dojke), HeLa (epitelni karcinom cerviksa)i MRC-5 (fetalni fibroblastni karcinom pluća). U zavr&scaron;noj fazi rada određena je antimikrobna aktivnost ekstrakata tropa odabranih sorti cvekle.</p> / <p> Beetroot (Detroit, Cardeal-F1, Egipatska, Bikor i Kestrel)<br /> pomace ethanol extracts were purified using solid phase<br /> extraction (SPE). Contents of total phenols, flavonoids and<br /> betalains in purified extracts were determined by spectrophotometric<br /> methods. HPLC analysis were used for quantitative<br /> and qualitative characterization of phenolic compounds<br /> and betalains in investigated extracts. ESR spectroscopy<br /> was used for investigation of antiradical activity of<br /> beetroot pomace extracts on stable DPPH and reactive<br /> superoxide anion and hydroxyl radicals. Antioxidant activity<br /> was determined spectrophotometrically on DPPH radicals<br /> and reducing power according to Oyaizu in the beetroot pomace<br /> extracts. Antiproliferative activity of investigated extracts<br /> was determined in vitro, testing their influence on the<br /> growth of three histologically different human cell lines:<br /> MCF-7 (breast adenocarcinoma), HeLa (cervix epithelioid<br /> carcinoma) and MRC-5 (fetal lung). Also, antimicrobial activity<br /> of beetroot pomace extracts was determined.</p>
27

Antiradikalska i antiproliferativna aktivnost ekstrakata odabranih biljaka iz familija rosaceae i ericaceae / Antiradical and antiproliferative activity of selected plantextracts from Rosaceae and Ericaceae family

Tumbas Vesna 14 June 2010 (has links)
<p>Acetonski ekstrakti bobičastog voća iz familija Ericaceae<br />(borovnica,<em> Vaccinium myrtillus</em> L., i brusnica, <em>Vaccinium<br />macrocarpon</em> L.) i Rosaceae (&scaron;ipak, <em>Rosa canina</em> L., i glog,<br /><em>Crataegus oxyacantha</em> L.) preči&scaron;ćeni su i frakcionisani<br />primenom ekstrakcije na čvrstoj fazi (SPE). Sadržaj ukupnih<br />polifenolnih jedinjenja, flavonoida i antocijana u preči&scaron;ćenim<br />ekstraktima određeni su spektrofotometrijskim metodama.<br />HPLC analizom utvrđen je kvalitativni i kvantitativni<br />sastav frakcija ekstrakata ispitivanih bobica. ESR spektroskopijom<br />ispitana je antiradikalska aktivnost frakcija ekstrakata<br />bobica na stabilne DPPH<sup>●</sup> i reaktivne superoksid anjon i<br />hidroksil radikale. ESR spektroskopijom ispitano je i<br />prisustvo slobodnih radikala antioksidanata nastalih tokom<br />reakcije frakcija ekstrakata bobica sa superoksid anjon<br />radikalima. U zavr&scaron;noj fazi rada ispitana je<em> in vitro</em><br />antiproliferativna aktivnost frakcija ekstrakata bobica, njihovim<br />delovanjem na rast tri histolo&scaron;ki različite humane ćelijske<br />linije: HeLa (epitelni karcinom cerviksa), HT-29 (adenokarcinom<br />debelog creva) i MCF-7 (adenokarcinom dojke).</p> / <p>Acetone extracts of berries form Ericaceae (bilberry, <em>Vaccinium<br />myrtillus</em> L., and cranberry, <em>Vaccinium macrocarpon</em><br />L.) and Rosaceae (rose hip, <em>Rosa canina</em> L., and hawthorn,<br /><em>Crataegus oxyacantha </em>L.) families were purified and fractionated<br />using solid phase extraction (SPE). Contents of total<br />polyphenols, flavonoids and anthocyanins in purified extracts<br />were determined by spectrophotometric methods.<br />HPLC analysis were used for quantitative and qualitative<br />characterization of investigated berry extracts fractions. ESR<br />spectroscopy was used for investigation of antiradical activity<br />of berry extracts fractions on stable DPPH<sup>●</sup> and<br />reactive superoxide anion and hydroxyl radicals. The<br />presence of antioxidant free radicals formed during reaction<br />of investigated berry extracts fractions with superoxide<br />anion radicals was also investigated by ESR. Antiprolixferative<br />activity of investigated berry extracts fractions was<br />determined<em> in vitro</em>, testing their influence on the growth of<br />three histologically different human cell lines: HeLa (cervix<br />epithelioid carcinoma), HT-29 (colon adenocarcinoma) i<br />MCF-7 (breast adenocarcinoma).</p>
28

Capacidade antioxidante de farinhas de resíduos de frutas tropicais. / Antioxidant capacity of tropical flour fruits residues.

Oliveira, Alane Cabral de 15 February 2008 (has links)
Economically advantageous alternatives to fully explore the antioxidant content of tropical fruit residues from juice processor industries have been currently studied in the State of Alagoas, Brazil. Thus, flour methanolic extracts of acerola (AC), passion fruit (PF) and pineapple (PA) residues were screened for their antioxidant capacity. For this, their total phenolic content, antioxidant capacity toward DPPH and toward the superoxide anion radical, together with analysis of their protective effect against membrane lipid peroxidation, caused by peroxyl radical, were determined in the flour methanolic extracts. In the last case, the phospholipid bilayer biomimetic model with the inclusion of a fluorescent probe was used. The statistical analysis employed the epi info version 6.04d (2001) program and Microsoft excel, using the test t, multivaried analysis and qui-square, considering p < 0.05 as significant. The results of total phenolic content of flour methanolic extracts of AC, PF and PA were 94.6 ± 7.4, 41.2 ± 4.2 and 9.1 ± 1.3 mg of gallic acid equivalents/ g of dry extract, respectively. AC showed the best total phenolic content and antioxidant capacity toward DPPH . PF showed the best antioxidant capacity to superoxide anion radical. Similar indexes of lipid peroxidation protection were observed with both AC and PF residues. Altogether, these data suggest that flour methanolic extracts of AC and PF residues may be useful as antioxidant supplements or food additives, notably the acerola (AC) extracts. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Alternativas economicamente vantajosas com exploração completa do conteúdo antioxidante de resíduos de frutas tropicais de fábricas de sucos foram estudadas no estado de Alagoas, Brasil. Assim, extratos metanólicos de farinhas de resíduos de acerola (FRAC), maracujá (FRMA) e abacaxi (FRAB) foram avaliados quanto a sua capacidade antioxidante. Para isso, foram analisados o conteúdo total de fenóis, a capacidade antioxidante frente aos radicais DPPH e ânion radical superóxido e o efeito de proteção à peroxidação da membrana lipídica, causada pelo radical peroxila, dos extratos metanólicos das farinhas. No ultimo caso, um modelo de membrana bilamelar fosfolipídica com uma sonda fluorescente foi usado. Para a análise estatística, foi utilizado o programa epi info versão 6.04d (2001) e o Microsoft Excel, usando teste t, análise multivariada e qui-quadrado, considerando um p < 0,05 como significativo. Os resultados para o conteúdo total de fenóis dos extratos metanólicos das farinhas de resíduos de acerola (FRAC), maracujá (FRMA) e abacaxi (FRAB) foram 94,6 ± 7,4, 41,2 ± 4,2 e 9,1 ± 1,3 mg de equivalentes de ácido gálico/ g de extrato seco, respectivamente. FRAC mostrou o melhor conteúdo de fenóis e capacidade antioxidante frente ao radical DPPH . FRMA mostrou a melhor capacidade antioxidante frente ao ânion radical superóxido. Resposta similar foi observada entre FRAC e FRMA quanto à proteção frente a peroxidação da membrana lipídica. De modo geral, estes dados sugerem que extratos metanólicos de farinhas de FRAC e FRMA podem ser úteis como suplementos antioxidantes ou aditivos alimentares, em especial, o extrato de acerola.
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Visokovredna funkcionalna jedinjenja iz sporednih proizvoda prerade paradajza / High-valuable functional compounds from tomato by-products

Stajčić Slađana 02 November 2012 (has links)
<p>Ekstrakcijom heksanom, a zatim 80% etanolom predhodno pripremljenog tropa od<br />IZ odabranih genotipova Bačka, Knjaz, Novosadski niski, O<sub>2</sub>, Rutgers i Saint Pierre<br />paradajza, dobijeni su heksanski i etanolni ekstrakti tropa. Sadržaj karotenoida u<br />heksanskim i polifenolnih jedinjenja, flavonoida i askorbinske kiseline u etanolnim<br />ekstraktima određen je spektrofotometrijskim metodama. Identifikacija i<br />kvantifikacija pojedinih karotenoida u heksanskim i polifenolnih jedinjenja u<br />etanolnim ekstraktima tropa paradajza izvedena je HPLC analizom. U ostacima<br />nakon ekstrakcija tropa paradajza određen je sadržaj prehrambenih vlakana.<br />Spektrofotometrijskim testovima određena je antiradikalska aktivnost na DPPH<br />radikale i redukciona sposobnost dobijenih ekstrakata. ESR spektroskopijom<br />ispitan je uticaj etanolnih ekstrakata na reaktivne hidroksil i superoksid anjon<br />radikale. Pored toga, ispitana je i helirajuća sposobnost etanolnih ekstrakata.<br />Antiradikalsko delovanje na DPPH radikale ostataka nakon ekstrakcija tropa<br />paradajza radikale, takođe je utvrđeno. Ispitana je in vitro antiproliferativna<br />aktivnost frakcija ekstrakata, njihovim delovanjem na rast tri histolo&scaron;ki različite<br />humane ćelijske linije: MCF-7 (adenokarcinom dojke), HeLa (epitelni karcinom<br />cerviksa) i MRC-5 (fetalni fibroblastni karcinom pluća). Rezultati ispitivanja<br />hemijskog sastava, antioksidativne i antiproliferativne aktivnosti ekstrakata, kao i<br />ostataka nakon ekstracija tropa odabranih genotipova paradajza ukazuju na<br />mogućnost iskori&scaron;ćenja ovog sporednog proizvoda kao potencijalnog izvora<br />prirodnih antioksidanata, koji bi na&scaron;li primenu u prehrambenoj, farmaceutskoj i<br />kozmetičkoj industriji.</p> / <p>Tomato pomaces obtained from selected tomato genotypes (Bačka, Knjaz, Novosadski niski,<br />O2, Rutgers and Saint Pierre) were extracted sequentially with hexane and 80% ethanol. The<br />content of carotenoids i hexane and total polyphenolics, flavonoids and ascorbic acid in<br />ethanolic extracts was determined by spectrophotometric methods. Identification and<br />quantification of individual carotenoids in hexane and polyphenolics in ethanolic extracts<br />was determined by HPLC analysis. The content of dietary fiber was determined in the<br />residues after extraction of tomato pomaces. The scavenging activity on DPPH radicals and<br />reducing power of the obtained extracts were determined spectrophotometrically. The<br />influence of ethanolic extracts on reactive hydroxyl and superoxide anion radicals was<br />examined by electron spin resonance (ESR) spectroscopy. In addition, the chelating ability of<br />ethanolic extracts was investigated. Scavenging effect on DPPH radicals of the residue after<br />extraction of tomato pomace, has also been established. Antiproliferative activity of<br />investigated extracts was determined in vitro, testing their influence on the growth of three<br />histologically different human cell lines: MCF-7 (breast adenocarcinoma), HeLa (cervix<br />epithelioid carcinoma) and MRC-5 (fetal lung). Based on the results of chemical analysis,<br />significant antioxidant and antiproliferative activity of the tomato waste extracts, as well as<br />residues after extraction showed that tomato waste obtained from different tomato genotypes<br />should be regarded as potential source of natural antioxidants, which can be used for various<br />purposes in the food, pharmaceutical and cosmetic industry.</p>
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[en] CHARGE TRANSFER COMPLEXES WITH HIGH SURFACE AREA BASED ON TIO2 NANOPARTICLES MODIFIED WITH BIDENTATE LIGANDS: SYNTHESIS, CHARACTERIZATION AND PHOTOCATALYTIC ACTIVITY UNDER LOW-POWER VISIBLE LIGHT / [pt] COMPLEXOS DE TRANSFERÊNCIA DE CARGA COM ALTA ÁREA SUPERFICIAL BASEADOS EM TIO2 NANOMÉTRICO MODIFICADO COM LIGANTES BIDENTADOS: SÍNTESE, CARACTERIZAÇÃO E ATIVIDADE FOTOCATALÍTICA SOB LUZ VISÍVEL DE BAIXA POTÊNCIA

LUCAS ARAUJO LIMA ALMEIDA 21 November 2023 (has links)
[pt] Os nanomateriais à base de TiO2 sensíveis à luz visível estão entre as alternativas mais promissoras para aplicações fotocatalíticas, como remediação ambiental. Os complexos de transferência de carga (CTCs) entre nano-TiO2 e ligantes bidentados, uma alternativa, têm sido amplamente estudados. No entanto, a eficiência da fotodegradação e o papel das espécies oxidantes reativas (ROS) não são totalmente compreendidos. Além disso, o desenvolvimento de CTCs baseados em TiO2 modificado com ácido malônico (MoA) ainda não foi investigado, até onde é sabido. Neste estudo, CTCs de TiO2-Acetilacetona (ACAC) e TiO2-MoA com alta área superficial foram sintetizados via sol-gel. Ambos os CTCs à base de TiO2preparados foram submetidos a testes de fotodegradação de tetraciclina e clorofenolcom e sem sequestrantes de ROS sob luz visível de baixa potência (26 W). Os CTCs TiO2-MoA foram totalmente caracterizadas por análises de DRX, MS-TGA, FTIR, adsorção-dessorção de N2, DRS, PL, EPR e XPS. A síntese sol-gel e o processo de calcinação adotado produziram CTCs de anatásio fortemente ligados (ligação covalente) com acetilacetona e ácido malônico, capazes de absorver ao longo do espectro visível quando calcinados a 300 graus C (TiO2-A300) e 270 graus C (TiO2-MoA270). Ambos os CTCs calcinados apresentam um único elétron preso na vacância de oxigênio (SETOV / centro de cores F+). Os CTCs TiO2-MoA-270 apresentaram áreas superficiais (>306 m2.g-1), volumes de mesoporos (>0,339 mL.g-1) e atividadefotocatalítica extremamente elevados, degradando aproximadamente 100 por cento de TC após 6 h. Os CTCs TiO2-MoA-270 e TiO2-A300 são uma fonte eficiente de geração de radicais *O2- e ineficientes geradores de radicais OH*. Os resultados desta pesquisa podem ser aplicados à síntese, via sol-gel, de outros CTCs, como os ácidos dicarboxílicos, e explorados em estudos posteriores sobre purificação do ar e produção de hidrogênio. / [en] Visible light-sensitive TiO2-based nanomaterials are among the most promising alternatives for photocatalytic applications, such as environmental remediation. The charge transfer complexes (CTCs) between nano-TiO2 and bidentate ligands, an alternative, have been widely studied. However, the photodegradation efficiency and role of reactive oxidizing species (ROS) are not fully understood. In addition, the development of CTCs based on TiO2 modified with malonic acid (MoA) have not yet been investigated, as far as the authors know. In this study, TiO2-Acetylacetone (ACAC) and TiO2-MoA CTCs with high surface area were synthesized via sol-gel route. Both as-prepared TiO2-based CTCs were subjected to tetracycline and chlorophenol photocatalytic degradation tests with and without ROS scavengers under low-power visible light (26 W). The TiO2-MoA CTCs were fully characterized by XRPD, MS-TGA, FTIR, N2 adsorption-desorption, DRS, PL, EPR and XPS analysis. The sol-gel synthesis and the calcination process adopted produced CTCs of nano-TiO2 anatase strongly bond (covalent bond) with acetylacetone and malonic acid, capable of absorbing along the visible spectrum when calcined at 300 degrees C (TiO2-ACAC-300) and 270 degrees C (TiO2- MoA-270). Both calcined CTCs present single electron trapped in oxygen vacancy (SETOV / F +color center). The TiO2-MoA-270 CTCs showed very high surface areas (>306 m2.g-1), mesopore volumes (>0.339 mL.g-1) and the highest photocatalytic activity, degrading approximately 100 percent of the TC after 6 h. The TiO2-MoA-270 and TiO2-A300 CTCs were an efficient source of *O2- radicals and inefficient generation of OH* radicals. The findings of this research can be applied to the synthesis, via sol-gel, of other CTCs, such as dicarboxylic acids, and explored in further studies on air purification and hydrogen production.

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