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.

Há, no Brasil, uma enorme diversidade de espécies vegetais, e um conhecimento popular de várias propriedades medicinais das mesmas. Dentre os estudos realizados com extratos de plantas, há um interesse especial na atividade antioxidante. Este trabalho, focado em atividade antioxidante, é dividido em duas partes: a primeira, utiliza a técnica de RPE para estudar a ação dos antioxidantes neutralizando os radicais livres, enquanto que a segunda utiliza a TFD para, em simulação computacional, ajudar a entender os resultados obtidos na primeira parte. Foram analisados 10 extratos vegetais: Swartzia langsdorffii, Machaerium villosum, Pterogyne nitens, Maytenus ilicifolia (casca de raiz), Pera glabrata, Aegiphyla sellowiana, Copaifera langsdorffii, Chrysophyllum inornatum, Iryanthera juruensis (folhas e sementes), Didymopanax vinosum. O estudo da atividade antioxidante com RPE utiliza dois métodos diferentes: o primeiro método mede a atividade antioxidante por meio do controle da quantidade de radicais livres, TEMPOL e DPPH, em contato com o extrato vegetal, enquanto que o segundo método utiliza o spin trap DMPO em conjunto com a reação de Fenton (Fe2+ + H2O2 => Fe3+ + HO- + HO) para analisar a ação dos extratos vegetais contra o radical hidroxila (OH?). A simulação computacional dos compostos TEMPOL, DPPH e DMPO é realizada em um método de primeiros princípios na Teoria do Funcional da Densidade, com uso de pseudopotenciais. O código utilizado é o SIESTA. As conclusões indicam que o extrato de Iryanthera juruensis, tanto de folhas quanto de sementes, exibe atividades antioxidantes bastante acentuadas, em todos os métodos utilizados. A simulação computacional aponta o TEMPOL menos reativo que o DPPH, devido a menor energia liberada em sua reação de redução. Sabendo que algumas destas espécies já são usadas popularmente por propriedades medicinais, estudos futuros para a correta identificação do agente antioxidante e seu possível uso, tanto na indústria alimentícia quanto na farmacêutica, deverão ser realizados. / There is, in Brazil, a great diversity of vegetable species, and a popular knowledge of several medicinal properties of the some of them. In studies carried out with plants? extracts, there is special interest in antioxidant activities. This work, focused in antioxidant activity, is divided in two parts: the first uses EPR technique to study the antioxidant activities neutralizing free radicals, while the second one uses DFT, in computational simulation, to understand the results obtained from the first part. Ten vegetable extracts were analyzed: Swartzia langsdorffii, Machaerium villosum, Pterogyne nitens, Maytenus ilicifolia (bark root extracts), Pera glabrata, Aegiphyla sellowiana, Copaifera langsdorffii, Chrysophyllum inornatum, Iryanthera juruensis (leaves and seeds), Didymopanax vinosum. The study with EPR uses two different methods: the first method measures the antioxidant activity by monitoring the amount of free radicals, DPPH and TEMPOL, that are in contact with the plant extract, the second method uses spin trap DMPO with Fenton reaction (Fe2+ + H2O2 => Fe3+ + HO- + HO) for the study of the plant extract antioxidant activity against the hydroxyl radical (OH?). The computational simulation of TEMPOL, DPPH and DMPO is carried out using a method of first principles within the Density Functional Theory and pseudopotentials. The code is SIESTA. The conclusions indicate that the Iryanthera juruensis extract, as of leaves as of seeds, exhibits accentuated antioxidants activities, in all of the used methods. The computational simulation indicated that the TEMPOL is less reactive than the DPPH, because the lower energy in its reduction reaction. As some of these species are already used popularly by medicinal properties, future studies for correct identification of the antioxidant compounds and its possible use, as in the food industry as in the pharmaceutical industry, should be realized.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-05-09T12:23:42Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação João Neto_Bibl Central.pdf: 1346533 bytes, checksum: c9180ed2cbbece23d0513b31179f3139 (MD5) / Made available in DSpace on 2016-05-09T12:23:42Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação João Neto_Bibl Central.pdf: 1346533 bytes, checksum: c9180ed2cbbece23d0513b31179f3139 (MD5) Previous issue date: 2015-05-22 / CAPEs / O Brasil é considerado o país com a maior biodiversidade do mundo, nele as formações vegetais do Bioma Caatinga e Mata Atlântica representam fontes potenciais para a prospecção de biomoléculas de interesse científico. Entre essas biomoléculas encontram-se aquelas com atividade antioxidante, substâncias que são capazes de neutralizar ou reparar a ação dos radicais livres e dessa forma combatendo o estresse oxidativo. Vários antioxidantes sintéticos estão presentes no mercado, porém estudos vêm demonstrando a possibilidade de efeitos tóxicos desses produtos sintéticos, fato que gerou estímulo para a busca de antioxidantes naturais. O presente trabalho visou investigar a atividade antioxidante de extratos de folhas de 5 espécies vegetais encontradas no Bioma Caatinga e Mata Atlântica, a saber: Abarema cochliacarpos (AC), Croton nummularius (CN), Myroxylon Peruiferum (MP), Stryphnodendron pulcherrimum (SP) e Tanaecium xanthophyllum (TX) por 3 metodologias in vitru: ensaio do DPPH, ABTS e fosfomolibdênio (capacidade antioxidante total - CAT). Adicionalmente foi realizada uma investigação fitoquímica dos extratos por cromatografia em camada delgada (CCD) bem como dosagem do teor de fenóis e flavonoides totais com o intuito de apontar os possíveis compostos ativos responsáveis por tal atividade. A análise do perfil fitoquímico evidenciou a presença de saponinas, fenilpropanoides e flavonoides em todas os extratos, enquanto que terpenoides e proantocianidinas foram encontrados em AC, alcaloides em CN, cumarinas em MP, proantocianidinas e mono-sesquiterpenoides em SP. As dosagens de fenóis e flavonóides totais dos extratos variaram de 28,84 a 120,39 (mg EAG. g-1 extrato) e 3,84 a 10,52 (mg EQ. g-1 extrato), respectivamente. Os valores de CI50 da atividade sequestradora de radicais DPPH variaram de 31,62 a 87,84 μg/mL. A porcentagem de sequestro de radicais ABTS variou de 20,92 a 75,69 % e a porcentagem da capacidade antioxidante total (%CAT) de 15,13 a 43,71 %. Foi evidenciado também uma correlação positiva entre o conteúdo de fenóis totais e atividade antioxidante pelos ensaios do radical ABTS (ρ = 0,926; R2 = 0,858) e CAT (ρ = 0,933; R2 = 0,872), o que indica o papel chave dos compostos fenólicos na atividade antioxidante dos extratos estudados. Mais estudos são requeridos no sentido de se isolar esses compostos para melhor caracterizá-los, assim como a realização de testes de atividade antioxidante in vivo. / Brazil is considered the most biodiverse country in the world. Its vegetation areas from the Caatinga and Atlantic forest biomes represent potential sources for scanning biomolecules of scientific interest. Among these biomolecules are those endowed with antioxidant activity, substances capable to neutralize or repair the action of free radicals and thus fighting against oxidative stress. Several synthetic antioxidants are out there in the market, but studies have shown the possible toxic effects of these synthetic products, which became a stimulus for the search of natural antioxidants. This study aims to investigate the antioxidant activity of leaf extracts from 5 plant species found in the Caatinga and Atlantic forest biomes, namely: Abarema cochliacarpos (AC), Croton nummularius (CN), Myroxylon Peruiferum (MP), Stryphnodendron pulcherrimum (SP) e Tanaecium xanthophyllum (TX) by 3 in vitru methodologies: DPPH, ABTS radical scavenging activities and phosphomolybdenum method (total antioxidant capacity – TAC). Additionally a phytochemical screening of the extracts by thin layer chromatography (TLC) was conducted as well as measurement of total phenolic and flavonoid content in order to point out the possible active compounds responsible for such activity. The phytochemical screening analysis revealed the presence of saponins, flavonoids and phenylpropanoids in all plant extracts. However, terpenoids and proanthocyanidins were found in CA, alkaloids in CN, coumarins in MP, proanthocyanidins and mono-sesquiterpenoids in SP. Total phenolic and flavonoid content of the extracts ranged from 28.84 to 120.39 (mg GAE. g-1 extract) and 3.84 to 10.52 (QE mg. g-1 extract), respectively. The IC50 values of DPPH radical scavenging activity ranged from 31.62 to 87.84 μg/mL. The percentage ABTS radical scavenging activity ranged from 20.92 to 75.69 % and the percentage total antioxidant capacity (%TAC) ranged from 15.13 to 43.71 %. It was also demonstrated a positive correlation between total phenolic content and ABTS radical scavenging activity (ρ = 0.926, R2 = 0.858) and TAC (ρ = 0.933, R2 = 0.872), which denotes the key role of phenolic compounds in the antioxidant activity of the extracts studied. Further studies are required in order to isolate these compounds to characterize them better as well as assessment of their antioxidant activity in vivo.

<p>Ekstrakcijom heksanom, a zatim 80% etanolom predhodno pripremljenog tropa od<br />IZ odabranih genotipova Bačka, Knjaz, Novosadski niski, O₂, 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>

Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-10-14T20:17:12Z No. of bitstreams: 2 Dissertação - Luisa Zaiden Carvalho Martins de Sá - 2013.pdf: 10244325 bytes, checksum: 02d04ed57549fd14027ffa31d1647977 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-10-16T18:33:07Z (GMT) No. of bitstreams: 2 Dissertação - Luisa Zaiden Carvalho Martins de Sá - 2013.pdf: 10244325 bytes, checksum: 02d04ed57549fd14027ffa31d1647977 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-10-16T18:33:07Z (GMT). No. of bitstreams: 2 Dissertação - Luisa Zaiden Carvalho Martins de Sá - 2013.pdf: 10244325 bytes, checksum: 02d04ed57549fd14027ffa31d1647977 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-03-28 / The consumption of wine has been associated with health promoting properties due to the high content of phenolic compounds, what makes wines an important dietary source of antioxidants. Jabuticaba fermented beverages, as much as wine, have a high content of phenolic compounds. In this study, traditional spectrophotometric methods (ABTS, DPPH, Folin-Ciocalteu) as well as novel methods (Cyclic Voltammetry - CV, Differential Pulse Voltammetry - DPV and Square Wave Voltammetry - SWV) have been used to evaluate the antioxidant activity of wines of different origin a jabuticaba fermented beverages and a jabuticaba brandy. Furthermore, an Electroanalytical Index (EI) has been proposed in order to allow the comparison of the antioxidant activity measured by electroanalytical methods. For the fermented beverages of jabuticaba, it has been demonstrated in the five methods that all three varieties, red, white and rose, have high antioxidant potential, very similar to a red dry wine, while the brandy has not shown any peaks in voltammetric analysis. In the analyzes by DPPH, red wines have shown about five times as much the antioxidant capacity of white wines, while for the EI it is twice as much when compared to white wines. Rose, white and fortified wines have shown lower EI than the red wine. It has been determined a Pearson correlation of -0.91097 between the DPPH method and the EI. The proposed EI allows comparison of the amount of electroactive compounds determined in the various wine samples analyzed. Considering the electroactive nature of the antioxidant compounds, electroanalytical methods have been demonstrated suitable for studying such compounds. Its main disadvantage was the high adsorption process due to the phenolic oxidation on the electrode´s surface, creating an isolating film on it. This process has been overcome by the use of carbon paste electrode. / O consumo de vinhos tem sido associado a benefícios à saúde por conter alto teor de compostos fenólicos, o que os torna uma importante fonte alimentar de antioxidantes. Bebidas fermentadas de jabuticaba, assim como os vinhos, também apresentam alto teor de compostos fenólicos. No presente trabalho, foram utilizados métodos espectrofotométricos clássicos (ABTS, DPPH, Folin-Ciocalteu) bem como métodos inovadores (voltametria cíclica, voltametria de pulso diferencial e voltametria de onda quadrada) para avaliação da atividade antioxidante de vinhos de diferentes origens e de bebidas fermentadas de jabuticaba e de uma aguardente de jabuticaba. Além disso, foi proposto um índice eletroanalítico (EI) que permite a comparação da atividade antioxidante medida pelos métodos eletroanalíticos. Para os fermentados de jabuticaba, foi demonstrado em todos os cinco métodos que todas as três variedades, a tinta, a rosê e a branca, apresentam potencial antioxidante elevado, bastante semelhante ao de um vinho tinto seco, enquanto a aguardente de jabuticaba não apresentou nenhum pico nas análises voltamétricas. Nas análises por DPPH, os vinhos tintos demonstraram possuir cerca de cinco vezes mais capacidade antioxidante que os vinhos brancos; já para EI, a diferença encontrada foi de cerca de duas vezes. Os vinhos rosê, branco, espumantes e fortificados demonstraram EI inferior ao dos vinhos tintos. Foi determinada uma correlação de Pearson de -0,91097 entre o método de DPPH e o EI. O EI proposto permite a comparação entre a quantidade de compostos eletroativos encontrados nas diferentes amostras de vinhos analisadas. Considerando-se a natureza eletroativa que os compostos antioxidantes apresentam, os métodos eletroanalíticos demonstraram ser métodos adequados, simples e rápidos para o estudo de tais compostos. A principal desvantagem encontrada nas análises por esse método foi a forte adsorção dos compostos fenólicos devido ao processo de oxidação que eles sofrem, formando um filme isolante na superfície do eletrodo, fato este contornado pelo uso de eletrodos de pasta de carbono.

L’objectif de ce travail est de contribuer à l'amélioration des connaissances phytochimiques et biologiques des plantes medicinales, afin d’en valoriser et d’en promouvoir l'usage en médicine traditionnelle au Vietnam. Dans ce travail de thèse, nous avons mené une étude phytochimique sur trois espèces végétales: Cleome chelidonii (Cleomaceae), Dolichandrone spathacea (Bignoniaceae) et Flacourtia rukam (Salicaceae). 90 composés ont été isolés et leurs structures ont été déterminées à l’aide des techniques spectroscopiques de RMN 1D et 2D, par la spectrométrie de masse ESI-MS, des données spectrales en UV, IR, la mesure du pouvoir rotatoire et des courbes de CD, et par comparaison avec les données de la littérature. Parmi ces composés, 29 correspondent à des molécules nouvellement décrites. Les composés isolés peuvent être classés en plusieurs groupes : flavonoïdes, iridoides, saponosides, mégastigmanes, glycosides phénoliques, alcaloïdes, …L’évaluation de l’activité anti-radicalaire (test DPPH) a été effectuée sur les flavonoides de C. chelidonii, et les activités antimicrobiennes des extraits et composés de D. spathacea et F. rukam ont été mesurées. Parmi les composés testés, le glycoside de quercétol nouveau CF-3 est le seul à posséder une activité anti-radicalaire importante (CI50 = 17,74 µM) et le glucoside phénolique nouveau FRP-4 possède l’activité antibactérienne la plus importante contre trois bactéries à Gram positif (CMI = 31,2 µg/ml) et deux bactéries à Gram négatif (CMI = 125 µg/ml). / The objective of this work is to contribute to the improvement of phytochemical and biological knowledge of medicinal plants, in order to enhance and promote their uses in traditional medicine in Vietnam. In this thesis, we carried out a phytochemical study on three plants: Cleome chelidonii (Cleomaceae) Dolichandrone spathacea (Bignoniaceae) and Flacourtia rukam (Salicaceae). 90 compounds were isolated and their structures were determinated using the spectroscopic techniques of 1D & 2D NMR and by the ESI-MS mass spectrometry, spectral data UV, IR, measurement of optical rotation and CD, and by comparison with the literature data. Among them, 29 are new molecules. The isolated compounds may be classified into many groups: flavonoids, iridoids, saponins, megastigmanes, phenolic glycosides, alkaloids...The antiradical activity of the flavonoids of C. Chelidonii was evaluated by the DPPH test, and the antimicrobial activity were examinated on all extracts and compounds of D. spathacea and F. rukam. Among the tested compounds, the new flavonoid CF-3 has a significant anti-radical activity (IC50 = 17.74 µM) and the new phenolic glucoside FRP-4 has the most significant antibacterial activity against three Gram-positive bacteria (MIC = 31.2 µg / ml) and two gram-negative bacteria (MIC = 125 µg /ml).

Analytical chemistry has developed throughout time to meet current needs. At present, the interest in biorefinery is growing, due to environmental awareness and the depletion of fossil resources. Biomass from agricultural and forestry industries has proven to be excellent raw material for different processes. Biorefinering valuable species such as bioactive species from biomass, without compromising the primary process of the biomass is highly desirable. Pressurised fluid extraction (PFE) using water and ethanol as a solvent was developed for extracting betulin from birch (Betula pendula) bark. Apart from betulin, stilbene glucosides such as astringin, isorhapontin and picied were also extracted from spruce (Picea abies) using PFE. PFE is an advanced technique that extracts at temperatures above the solvent’s atmospheric boiling point. The applied pressure in PFE is mainly to maintain the liquid state of the extraction solvent. Parameters such as type of solvent, temperature, and time affect the extraction selectivity and efficiency. Therefore it is necessary to comprehend these parameters in order to optimise extraction. The DPPH (1,1-diphenyl-2-picrylhydrazyl) assay was used to determine the antioxidant capacity and activity of the obtained bioactive species. The results showed high antioxidant capacity in bioactive species that were extracted at an elevated temperature, 180°C. Extraction and degradation occur simultaneously during the extraction. Hence, it is crucial to separate these two processes in order to obtain the actual value. An online hyphenated system of chromatographic separation electrochemical mass spectrometric detection was developed (LC-DAD-ECD-MS/MS). The electrochemical detector facilitates real-time monitoring of the antioxidant capacity and activity of each antioxidant and its oxidation products. This developed LC-DAD-ECD-MS/MS method enabled rapid screening of antioxidants and created a fingerprint map for their oxidation products. Characterisation and molecular elucidation of bioactive species were also performed. Degradation of bioactive species was investigated with the said online system and birch bark extract was compared with birch bark extracts that were hydrothermally treated. The obtained results showed some degradation of antioxidants at 180°C. In summary, the aim of this thesis was to develop analytical methods integrated with sustainable chemistry for extraction of bioactive species in biomass from the forestry industry. A novel online system using selective and sensitive detectors such as diode-array, electrochemical, and tandem mass spectrometry was developed to rapidly determine the antioxidant capacity and activity of antioxidants. Furthermore, tandem mass spectrometry enables identification of unknown bioactive species without the need of reference samples. / Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 719

Made available in DSpace on 2016-06-02T19:30:12Z (GMT). No. of bitstreams: 1 6721.pdf: 2764879 bytes, checksum: ca82bcb193d5ae0d2e21032afd6ed1dd (MD5) Previous issue date: 2015-03-30 / Financiadora de Estudos e Projetos / The Brazilian savanna holds the richest flora among the tropical savannas, being one of the hot spots for conservation of the biodiversity in the world. However, the chemical potential of its plant species is still underused while deforestation and loss of biodiversity are main issues. In the Brazilian savanna, plants are exposed to environmental pressures (competition, pathogens, drought, injurious UV radiation, etc) that may stimulate the production of secondary metabolites as a defense. These compounds can generally be explored due to their biological properties. The aim of this study was to assess the fungicidal and antioxidant properties of plants from the Brazilian savanna. First a screening was conducted with ethanolic leaf extracts of 28 plant species. There was no activity against Alternaria alternata, a filamentous fungi that causes one of the most severe diseases in tangerines (Alternaria brown spot disease). However, the same extracts presented a high antioxidant potential associated with the phenolic content. Other investigations were made using infusion extractions focusing on the Myrtaceae family, one of the most abundant families of plants in the Brazilian savanna. Most species also presented high antioxidant activity and phenolic content. At last, the extraction of piceid, a compound with high antioxidant activity, was optimized from roots of Psidium laruotteanum. A response surface methodology was applied to assess the influence of solvent, pH, amplitude, cycle, temperature and solvent-solid ratio using an ultrasound extraction. A high amount of piceid was extracted and Psidium laruotteanum root was found to be the most concentrated source of this compound reported up to date. These results point the plant species from the Brazilian savanna as an important source of bioactive compounds, emphasizing the need to preserve and study its biodiversity. / O cerrado possui a flora mais rica entre as savanas tropicais, sendo um dos pontos quentes para conservação da biodiversidade no mundo. No entanto, o potencial químico de suas espécies vegetais é ainda subutilizado, enquanto o desmatamento e a perda de biodiversidade são questões de grande relevância. No cerrado, as plantas estão expostas a pressões ambientais (competição, patógenos, seca, radiação UV nociva, etc) que podem estimular a produção de metabólitos secundários como defesa. Estes compostos geralmente podem ser explorados devido suas propriedades biológicas. O objetivo deste estudo foi avaliar as propriedades fungicidas e antioxidante de plantas do cerrado. Primeiro uma triagem foi realizada com extratos etanólicos de folhas de 28 espécies vegetais. Não houve nenhuma atividade contra Alternaria alternata, um fungo filamentoso que causa uma das doenças mais severas em tangerinas (mancha marrom de Alternaria). No entanto, os mesmos extratos apresentaram um potencial antioxidante elevado associado com o conteúdo fenólico. Outras investigações foram feitas usando extrações por infusão enfocando a família Myrtaceae, uma das famílias mais abundantes de plantas no cerrado. A maioria das espécies apresentou alta atividade antioxidante e alto conteúdo fenólico. Por fim, a extração de piceido, um composto com alta atividade antioxidante, foi otimizada de raízes de Psidium laruotteanum. Uma metodologia de superfície de resposta foi aplicada para avaliar a influência do solvente, pH, amplitude, ciclo, temperatura e razão solvente-sólido usando uma extração de ultrasonido. Uma alta quantidade de piceido foi extraída e a raiz de Psidium laruotteanum se mostrou como sendo a fonte mais concentrada deste composto relatada até hoje. Estes resultados apontam as espécies de plantas do cerrado como uma importante fonte de compostos bioativos, enfatizando a necessidade de preservar e estudar sua biodiversidade.

CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesta tese, apresenta-se o desenvolvimento de métodos eletroquímicos que empregam a análise por injeção em batelada (BIA) com detecção amperométrica para determinação da capacidade antioxidante de amostras de chá e extratos vegetais e determinação de astaxantina em salmão. O primeiro método foi desenvolvido para determinar a capacidade antioxidante de amostras de chá e extratos de plantas com base na medida do consumo de radicais DPPH, uma vez que este radical é eletroativo. Com este método, mediu-se a concentração eficaz ou o valor CE50 que corresponde à concentração necessária de amostra ou padrão capaz de consumir 50% de radicais DPPH. Para a determinação exata do CE50, as amostras foram incubadas com radical DPPH durante 1 h, pois muitos compostos polifenólicos tipicamente encontrados nas plantas e responsáveis pela atividade antioxidante exibem cinética lenta. O sistema BIA com detecção amperométrica utilizando um eletrodo de carbono vítreo apresentou alta precisão (DPR = 0,7%, n = 12), baixo limite de detecção (1 μmol L-1) e seletividade do radical DPPH (livre de interferências de antioxidantes). Estes resultados contribuíram para baixos limites de detecção para os antioxidantes ácido gálico e butilhidroxitolueno (0,015 e 0,19 μmol L-1, respectivamente). O segundo método desenvolvido baseou-se na oxidação eletroquímica do antioxidante astaxantina em eletrodo de carbono vítreo para sua determinação amperométrica em amostras de salmão. O método consistiu na injeção de 80 μL de extrato da amostra diretamente no eletrodo de carbono vítreo imerso em solução composta por acetona, diclorometano e água (80:10:10 v/v) contendo 0,1 mol L-1 HClO4. Este método apresentou vantagens que incluem alta precisão (DPR de 2,4%), frequência analítica de 240 h-1 e baixo limite de detecção (0,3 μmol L-1, que corresponde a 0,1 μg g-1) para a análise de amostras de salmão extraídas com acetona. Valores de recuperação entre 83 e 97% foram obtidos. Além disso, ambos métodos propostos são promissores pois trazem a possibilidade do uso de sistemas portáteis uma vez que a instrumentação usada (micropipeta eletrônica e potenciostato) está disponível comercialmente. / In this thesis, we present the development of electrochemical methods using batch injection analysis (BIA) with amperometric detection to determine the antioxidant capacity of tea samples and plant extracts and determination of astaxanthin in salmon. The first method was developed to determine the antioxidant capacity of tea samples and plant extracts based on the extent of the consumption of DPPH radicals, since this radical is electroactive. In this method the effective concentration or EC50 value corresponding to the required concentration of sample or standard capable of consuming 50% of DPPH radicals was measured. For the exact determination of the EC50, the samples were incubated with DPPH radical for 1 h, since many polyphenolic compounds typically found in plants and responsible for the antioxidant activity exhibit slow kinetics. The BIA system with amperometric detection using a vitreous carbon electrode showed high precision (RSD = 0.7%, n = 12), low detection limit (1 μmol L-1) and DPPH radical selectivity (free of antioxidant interferences). These results contributed to low detection limits for the antioxidants gallic acid and butylhydroxytoluene (0.015 and 0.19 μmol L-1, respectively). The second method developed was based on the electrochemical oxidation of the antioxidant astaxanthin on a glassy carbon electrode for its amperometric determination in salmon samples. The method consisted of the injection of 80 μL of sample extract directly into the vitreous carbon electrode immersed in a solution composed of acetone, dichloromethane and water (80:10:10 v/v) containing 0.1 mol L-1 HClO4. This method presented advantages that include high accuracy (RSD of 2.4%), analytical frequency of 240 h-1 and low detection limit (0.3 μmol L-1, corresponding to 0.1 μg g-1) for The analysis of salmon samples extracted with acetone. Recovery values between 83 and 97% were obtained. In addition, both proposed methods are promising because they bring the possibility of using portable systems since the instrumentation used (electronic micropipette and potentiostat) is commercially available. / Tese (Doutorado)

Diploma thesis deals with currant (Ribes L.) and substances which currants contain especially anthocyanin pigments, vitamin C and antioxidants. In theoretical part is described basic characteristic about plant, including varieties of currants. The following chapters include a list of active substances which the fruit contains and also the list of some possibilities of processing and utilization of currant especially in the food industry. Big attention is given to anthocyanins, their characteristics, utilization in the food industry, factors that affect their stability and especially methods of determination. In conclusion, the theoretical part describes importance and methods of determination of vitamin C and antioxidant capacity. Selected nutritional parameters were determined in fifteen known and in three unknown varieties of currants. Anthocyanins were measured spectrophotometrically and determined by HPLC in color samples. By pH differential method was evaluated a content of monomeric and polymeric pigments. By HPLC method were identified individual anthocyanin pigments contained in fruits. Also, content of ascorbic acid was determined by HPLC in all varieties. Antioxidant capacity of white currants measured by DPPH was compared.