Estudo fitoquímico dos extratos de folhas e galhos de Peperomia villipefiola (\"hierba de la plata\"), coletada no Peru, resultou no isolamento e caracterização da miristicina (3-metoxi-4,5-metilenedioxi-alil-benzene) e sete novos cromenos. Os cromenos tiveram suas estruturas elucidadas através de análises espectroscópicas como sendo: 5-hidroxi-7-metil-2,2-dimetil-2H-1-cromeno-6-carboxilato de metila (PVL1), 7-metil-5-metoxi-2,2-dimetil-2H-1-cromeno-8-carboxilato de metila (PVL2), 7-hydroxy-5-metil-2,2-dimetil-2H-1-cromeno-6-carboxilato de metila (PVL3), 5-metil-7-metoxi-2,2-dimetil-2H-1-cromeno-6-carboxilato de metila (PVL4), ácido 7-hidroxi-5-metanol-2,2-dimetil-2H-1-cromeno-6-carboxílico (PVL5), ácido 5-metanol-7-metoxi-2,2-dimetil-2H-1-cromeno-6-carboxílico (PVL6) e 5-acetoximetanol-7-hidroxi-2,2-dimetil-2H-1-cromeno-6-carboxilato de metila (PVL7). Uma proposta biossintética foi sugerida, no qual o anel aromático seria formado pela via policetídica enquanto que a porção isoprênica poderia ser oriunda tanto da via do mevalonato quanto da via do fosfato de metileritriol. / The leaves and stems extracts from the Peperomia villipetiola (\"herb of the silver\"), collected in Peru, yielded myristicine (3-methoxy-4,5-methy/enedioxy-allylbenzene) and seven new chromenes. The chromenes, all new compounds, had their structures elucidated by means of spectroscopic analysis as: methyl 5-hydroxy-7-methyl-2,2-dimethyl-2H-1-chromene-6-carboxylate (PVL1), methyl 5-methoxy-7-methyl-2,2-dimethyl-2H-1-chromene-8-carboxylate (PVL2), methyl 7-hydroxy-5-methyl-2,2-dimethyl-2H-1-chromene-6-carboxylate (PVL3), methyl 7-methoxy-5-methyl-2,2-dimethyl-2H-1-chromene-6-carboxylate (PVL4), 5-methanol7-hydroxy-2 ,2-dimethyl-2H-1-chromene-6-carboxylic acid (PVL5), 5-methanol-7-methoxy-2,2-dimethyl-2H-1-chromene-6-carboxylic acid (PVL6), and methyl 5-acetoxymethanol-7-hydroxy-2,2-dimethyl-2H-1-chromene-6-carboxylate (PVL7). A biosynthetic scheme was suggested in which the aromatic ring should be formed by polyketide pathway while the isoprenyl moiety either from mevalonic acid or methylerythriol phosphate pathway.

Neste trabalho foram reativadas 51 linhagens fúngicas isoladas a partir da ascídia Didemnum ligulum. Após a reativação, as linhagens foram cultivadas em meio de cultura líquido (250 mL), a partir dos quais foram obtidos os respectivos extratos brutos. Os extratos foram avaliados em bioensaio de atividade citotóxica, em três linhagens de células tumorais. Observou-se que 14 extratos apresentaram atividade citotóxica. Os extratos foram avaliados por HPLC-UV-MS para determinação do perfil químico. Após esta análise, a linhagem DLM2-12, identificada como Penicillium citrinum, foi selecionada para crescimento em meio de cultura líquido em quantidade suficiente para se realizar o isolamento dos metabólitos secundários do extrato de seu meio de cultura. O extrato de 250 mL do meio de cultura de P. citrinum foi submetido a diferentes métodos de separação cromatográfica. Estas separações permitiram o isolamento e identificação da citrinina (47) como sendo majoritária. Para isolamento de outros compostos presentes no extrato, a linhagem foi cultivada em maior escala (8 L) e obtido o extrato de seu meio de cultura. O novo extrato foi submetido a separações cromatográficas em gel de Sephadex LH-20, sílica gel e sílica gel derivatizada com grupo cianopropila, bem como purificações por HPLC. Estas separações permitiram o isolamento e identificação de três quinolonas, as quinolactacinas C (50) e B (53) e a quinolactacina E (51), inédita na literatura, um ácido tetrâmico, o penicilenol A (54) e duas antraquinonas, a citreoroseína (57) e a emodina (61). As antraquinonas citreoroseína (57) e emodina (61) foram submetidas aos bioensaios de atividade antiviral, antimicrobiana, Leishmanicida e citotóxica. A citreoroseína (57) apresentou atividade contra as linhagens virais BVDV, HSV1 e aMPV e apresentou atividade citotóxica ativa frente à linhagem celular HCT-116 sendo inativa frente às linhagens celulares HL-60, SF295, OVCAR-8, K562, HCT-8, MDA-MB435 e MVF-7. A emodina (61) apresentou atividade contra as linhagens virais BVDV, HSV1, aMPV e hepatite C, atividade antimicrobiana, atividade Leishmanicida, atividade citotóxica frente às linhagens celulares HL-60, HCT-116, SF295, OVCAR-8, K562 e HCT-8 sendo inativa frente às linhagens celulares MDA-MB435 e MVF-7. / The present investigation describes the isolation of secondary metabolites from the culture medium of a marine-derived strain of the fungus Penicillium citrinum. Initially, 51 fungal strains isolated from the ascidian Didemnum ligulum and preserved in stereilized sea water were re-activated in Petri dishes. After reactivation, the strains were grown in 250 mL of liquid culture medium. All media were extracted with EtOAc and, after evaporation, aliquots of the extracts were evaluated in a cytotoxicity assay on three tumor cell lines. It was observed that 14 extracts showed cytotoxic activity. These 14 extracts were analyzed by HPLC-UV-MS in order to investigate their corresponding chemical profile. As a result, the DLM2-12 strain, identified as Penicillium citrinum, was selected for semi-preparative growth in liquid culture medium in sufficient quantity to accomplish the isolation of secondary metabolites. A first growth in 250 mL of culture medium yielded an extract which was subjected to various chromatographic separations, to give citrinin (42) as the major compound. An additional growth of P. citrinum DLM2-12 in a larger volume (8 L) yielded an extract which was subjected to chromatographic separations on Sephadex LH-20, cyanopropyl-bonded silica gel, and by reversed-phase HPLC. These separations gave, after the identification of pure compounds: a) three quinolones, quinolactacins C (51) and B (54) and a new quinolactacin (52), unreported in the literature; b) the tetramic acid penicilenol A (55), and; c) two anthraquinones, citreorosein (57) and emodin (61). The anthraquinones 57 and 61 were evaluated in antiviral, antimicrobial, antileishmanial and cytotoxic assays. Citreorosein (57) displayed activity against the viral strains BVDV, HSV1 and aMPV and showed cytotoxicity against the HCT-116 cell line, being inactive against HL-60, SF295, OVCAR-8, K562, HCT-8, MDA-MB435 and MVF-7 cell lines. Emodin (61) displayed activity against the viral strains BVDV, HSV1, AMPV and hepatitis C, as well as antimicrobial, leishmanicidal, as well as cytotoxic activity against HL-60, HCT-116, SF295, OVCAR-8, K562 and HCT-8 cancer cell lines, being inactive against MDA-MB435 and MVF-7 cell lines.

Micro-organismos são profícuos produtores de produtos naturais bioativos. Diversos fármacos inovativos e de extrema importância clínica são de origem microbiana, como antibióticos, antitumorais, imunossupressores e agentes hipolipêmicos. A maioria dos fármacos de origem microbiana é produzida por actinobactérias. A estreita associação de micro-organismos com plantas, insetos, crustáceos e organismos marinhos, pode induzir a produção de substâncias bioativas, que eventualmente conferem vantagens adaptativas e ecológicas ao macro-organismo hospedeiro. Ambientes marinhos e áreas de transição como os manguezais são ainda pouco explorados para estudos químicos e farmacológicos dos micro-organismos presentes nos solos e em simbiose com outros hospedeiros. Neste sentido, o presente trabalho visou o estudo químico monitorado por ensaios de citotoxicidade em células cancerígenas de dois micro-organismos, Streptomyces sp. Act1 e Streptomyces sp. Act2, isolados da casca do caranguejo do maguezal, Ucides cordatus, coletado em Cananéia, SP. Estes micro-organismos apresentaram atividade antagônica frente ao fungo patogênico Aspergillus niger, confirmando o potencial para produção de substâncias bioativas. Os micro-organismos foram cultivados em diferentes meios de cultura para avaliar o potencial de crescimento, perfil químico dos extratos obtidos e atividade citotóxica dos extratos e subfrações. Os meios de cultura escolhidos foram meio líquido ISP-2 e meio sólido (arroz), e ainda, nestas mesmas condições foi avaliado o efeito do uso de água do mar de forma comparativa. Os micro-organismos desenvolveram-se adequadamente nos diferentes meios de cultivo. Os fracionamentos dos extratos obtidos nos experimentos evidenciaram características polares das subfrações obtidas, e neste sentido foram necessárias adaptações das técnicas de separação, incluindo fases estácionárias como sephadex LH-20 e fase reversa. Os ensaios de citotoxicidade frente às linhagens de células tumorais com os extratos obtidos mostraram o grande potencial das linhagens em estudo, em especial a linhagem Streptomyces sp. Act-2 cultivada na presença de água do mar. / Abstract Microorganisms are prolific producers of bioactive natural products. Most of innovative pharmaceuticals that have useful clinical importance have been isolated from from microorganisms, such as antibiotics, anticancer drugs, immunosuppressive drugs and lipid-lowering agents. Most of the drugs of microbial origin are produced by actinomycetes. The close association of micro-organisms with plants, insects, crustaceans or marine organisms may induce the production of bioactive substances. These natural products may confer adaptive advantages to the environment and to the host organism. Marine and transitional areas such as mangroves are still under explored for chemical and pharmacological studies of both soil microorganisms and symbiotic microorganisms. In this sense, this work aimed a chemical study of two actinobacteria strains, Streptomyces sp. Act1 and Streptomyces sp. Act2, guided by cancer cells cytotoxicity assays. Both microorganisms were isolated from the shell of the mangrove crab Ucides cordatus, collected in Cananéia, SP. These microorganisms showed antagonistic activity against the pathogenic fungus Aspergillus niger, confirming the potential for production of bioactive substances. Microorganisms were cultured in different culture media to assess the potential for growth, chemical profile of extracts and cytotoxic activity of extracts and subfractions. The culture media were chosen using liquid (ISP-2) and solid medium (rice). The effect of addition of saline water in the culture media has also been evaluated. The microorganisms developed adequately in different culture media. The fractions of extracts obtained from the experiments showed characteristics of polar subfractions obtained, requiring the use of sephadex LH-20 and reverse phase as chromatographic stationary phases. Cytotoxic assays of the extracts against cancer cell lines showed the great potential of the strains under study, mainly Streptomyces sp. Act2. grown in the presence of seawater.

As algas são fontes importantes de matérias-primas e compostos biologicamente ativos utilizados na indústria farmacêutica, cosmética e alimentícia. As macroalgas vermelhas marinhas Gracilaria birdiae e Gracilaria domingensis são abundantemente encontradas no litoral nordeste brasileiro e apresentam alto potencial biológico para o fornecimento de compostos utilizados na indústria. Após o desenvolvimento e padronização da obtenção dos extratos e frações foram avaliadas as suas atividades antioxidante in vitro e in vivo, utilizando-se diferentes técnicas. In vitro, foram avaliadas a atividade sequestrante de radicais DPPH, a atividade sobre o sistema Luminol-HRP- H2O2, o poder redutor e atividade quelante de íons ferro. As frações mais apolares apresentaram-se mais ativas. Os efeitos sobre as funções de macrófagos humanos através de ensaios sobre a atividade de “burst ” repiratório, observando-se um incremento da atividade dos macrófagos na presença da fração metanólica. A atividade antimicrobiana dos extratos foi avaliada através da metodologia de determinação da concentração inibitória mínima sobre 4 espécies de bactérias gram-negativas sendo estas Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumonae ATCC 10231, Salmonella typhi ATCC 19430 e 4 microrganismos gram-positivos sendo Staphylococcus aureus ATCC 29213, Streptococcus pneumoniae ATCC 49 619 , Bacillus subtilis ATCC 6633 e Enterococcus faecalis ATCC 29212. Nenhuma das frações nem o extrato aquoso bruto apresentaram capacidade de inibição do crescimento bacteriano nas concentrações testadas (1000, 500, 250, 125, 62,5 e 31,25 µg/mL). O ensaio antifúngico contou com 2 espécies: Candida albicans ATCC 10231, Candida parapsilosis ATCC 29212. Apenas o extrato protéico apresentou atividade de inibição de crescimento das leveduras testadas. / Algae are important sources of raw material and biological active compounds used in pharmaceutical, cosmetic and food industries. Marine Brazilian red macroalge, Gracilaria birdiae e Gracilaria domingensis, are found in the Brazilian northeast coast and have high potential for industries. The aim of this work was to evaluate the antioxidant activity of the extracts by different techniques such as DPPH scavenging activity, ROS generation by the Luminol- HRP-H2O2 system, reducing power determination and metal quelating activity. The most apolar fraction showed highest antioxidant activity. The effects of methanolic fractions on mice macrophages oxidative burst were evaluated by luminol-enhanced chemiluminescence assay and an increment of the respiratory burst was observed. Algae fractions and extracts were tested for antimicrobial assays led by determining the Minimum Inhibitory Concentration - MIC. Gram-negative bacteria tested were Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumonae ATCC 10231 and Salmonella typhi ATCC 19430 and four Gram-positive bacteria Staphylococcus aureus ATCC 29213, Streptococcus pneumoniae ATCC 49 619 , Bacillus subtilis ATCC 6633 and Enterococcus faecalis ATCC 29212. None of the extracts and fractions showed activity against these microorganisms in the concentration of 1000 µg/mL. Two fungi species were tested: Candida albicans ATCC 10231, Candida parapsilosis ATCC 29212. Only the protein extract was effective against the tested fungi species

Fungos do gênero Colletotrichum são considerados um dos principais fitopatógenos do mundo, comprometendo diversas culturas e causando danos econômicos e sociais para diversos países, inclusive o Brasil. Apesar de medidas de controle já serem empregadas, estas nem sempre são eficazes, motivo pelo qual se faz necessária a busca por novas opções de controle que possam atuar no manejo integrado. Dentre estas, encontram-se os metabólitos secundários produzidos por fungos endofíticos, os quais estão envolvidos na produção de compostos de interesse biotecnológico, com aplicações em diversas áreas, inclusive a agronômica. Neste contexto, o presente trabalho de doutorado teve por objetivo explorar o potencial biológico e químico de metabólitos secundários produzidos por fungos endofíticos isolados de guaranazeiros da Amazônia, avaliando sua atividade antifúngica \"in vitro\" a Colletotrichum gloeosporioides, isolado da cultura do guaranazeiro, a C. acutatum e C. gloeosporioides, isolados da cultura do pimentão. Para tanto, 16 linhagens de fungos endofíticos foram avaliadas em ensaio biológico por cultivo pareado e pelo método de difusão em disco contra Colletotrichum spp. Observou-se que quatro linhagens se mostraram mais promissoras, as quais foram selecionadas para o estudo de bioprospecção. A partir do extrato bruto do endófito Aspergillus flavus (272) foi isolado o composto ativo asperfuran, que apresentou atividade inibitória aos três fitopatógenos, com CI50 < 100 &mu;g disco-1, semelhante ao fungicida comercial difenoconazol. A partir do extrato bruto de Xylaria sp. (214) foi isolado o composto ativo citocalasina D, que apresentou atividade inibitória a C. gloeosporioides isolado do guaranazeiro, com CI50 > 500 &mu;g disco-1. A partir do extrato bruto de Xylaria sp. (249) foi isolado o composto ativo ácido pilifórmico, que apresentou atividade inibitória a C. gloeosporioides isolado do guaranazeiro, com CI50 de 500 &mu;g disco-1 e à C. acutatum isolado o pimentão, com CI50 de 300 &mu;g disco-1. E, a partir do extrato bruto de Talaromyces aculeatus (507) foram isolados três compostos, da classe dos ésteres ftalicos, sendo um ativo. A fração antecessora destes três compostos apresentou atividade inibitória a C. gloeosporioides isolado do guaranazeiro, com CI50 > 500 &mu;g disco-1. A partir do extrato bruto de T. aculeatus também foi isolado um composto ativo parcialmente identificado e um composto ativo semi-purificado. A fração antecessora destes dois compostos apresentou atividade inibitória aos dois C. gloeosporioides, com CI50 > 300 &mu;g disco-1 e a C. acutatum, com CI50 em torno de 150 &mu;g disco-1. A atividade antifúngica destes compostos a fungos do gênero Colletotrichum está sendo relatada pela primeira vez neste estudo. / Colletotrichum fungi are considered one of the main pathogens in the world, affecting different cultures and causing social and economic damage to several countries, including Brazil. Despite control measures already being employed, these are not always effective, which is why the search for new control options that can act in the integrated management is necessary. Among these, the secondary metabolites produced by endophytes are involved in the production of compounds of biotechnological interest, with applications in several areas, including the agronomic. In this context, this study aimed to explore the biological and chemical potential of secondary metabolites produced by endophytic fungi isolated from the Amazonian guarana, evaluating their antifungal activity \"in vitro\" to Colletotrichum gloeosporioides, isolated from the culture of guarana and C. acutatum and C. gloeosporioides, isolated from the red pepper crop. For this purpose, 16 strains of endophytic fungi were evaluated in biological assay of dual culture and disk diffusion method against Colletotrichum spp. Four strains of these strains presented promising results which were selected for bioprospecting. From the crude extract of the endophyte Aspergillus flavus (272) was isolated the active compound asperfuran, which showed inhibitory activity to three pathogens, with IC50 <100 &mu;g disk-1, similar to the commercial fungicide difenoconazole. From the crude extract of Xylaria sp. (214) was isolated the active compound cytochalasin D, which showed inhibitory activity against C. gloeosporioides isolated from guarana (IC50> 500 &mu;g disk-1). From the crude extract of Xylaria sp. (249) was isolated the active compound piliformic acid, which showed inhibitory activity against C. gloeosporioides isolated from guarana (IC50 of 500 &mu;g disk-1) and C. acutatum isolated from red pepper (IC50 of 300 &mu;g disk-1). And from the crude extract of Talaromyces aculeatus (507) were isolated three compounds, of phthalate esters class, one of them with activity. The predecessor fraction of these three compounds showed inhibitory activity against C. gloeosporioides isolated from guarana (IC50> 500 &mu;g disk-1). From the crude extract of T. aculeatus it was also isolated a partially identified active compound and a semi-purified active compound. The predecessor fraction of these two compounds showed inhibitory activity to both C. gloeosporioides (IC50> 300 &mu;g disk-1) and to C. acutatum (IC50 around 150 &mu;g disk-1). The antifungal activity of the compounds isolated in this study is being reported for the first time against fungus of the genus Colletotrichum.

Causada por protozoários do gênero Leishmania, a leishmaniose é uma doença infecciosa que afeta milhões de pessoas em todos os continentes. São grandes os desafios no tratamento da leishmaniose porque os fármacos atualmente disponíveis apresentam alta toxicidade, efeitos colaterais, alto custo e resistência parasitária. Sendo assim, faz-se necessário o desenvolvimento de novas drogas para o tratamento da doença de maneira mais eficiente. A investigação de novas alternativas terapêuticas, novos alvos bioquímicos, em particular a arginase em de Leishmania (L) amazonensis, é considerada um alvo interessante na busca de novos compostos leishmanicidas. A via bioquímica em que está envolvida a arginase é fundamental para a manutenção do ciclo de vida do parasito, sendo responsável pela hidrólise de L-arginina em L-ornitina em mamíferos. Muitos compostos oriundos de produtos naturais tem sido relatados como inibidores da arginase de L. (L.) amazonensis e a presença de grupos hidroxila em suas estruturas mostraram ser importantes na atividade inibidora da enzima. O objetivo desse trabaho estudar a interação bioquímica entre a enzima arginase de L. (L.) amazonensis, extratos vegetais, flavonoides e derivados do ácido cafeico. O extrato acetônico de folhas de Qualea grandiflora apresentou maior capacidade inibitória da arginase (IC50 = 1,7 &plusmn; 01 &micro;g/mL) dentre os extratos analisados. Dentre os flavonoides, o composto mais potente foi a taxifolina (IC50 = 1,7 &plusmn; 0,2 &micro;M). O verbascosídeo foi o derivado do ácido cafeico com maior potencial de inibição da arginase (IC50 = 0,5 &plusmn; 0,2 &micro;M). As estruturas desses compostos podem servir como referência no desenvolvimento de novas drogas para o controle da leishmaniose, que tenham como alvo a arginase. / Caused by protozoa of the genus Leishmania, leishmaniosis is an infectious disease that affects millions of people on all continents. The currently available drugs are highly toxic, expensive, have side effects and parasitic resistance and for these reasons there is a need of developing new drugs to more effective treatment of the disease. The research of new therapeutic alternatives, new biochemical targets, in particular the arginase of Leishmania (Leishmania) amazonensis is considered an interesting target in the search for new compounds leishmanicidal. The biochemistry of arginase pathway is essential for the survival of the parasite, is also responsible for hydrolysis of L- arginine to L- ornithine in mammals. Many compounds from natural products has been reported as inhibitors of arginase L. (L.) amazonensis, and the presence of hydroxyl groups in their structures shown to be important for inhibitory activity of the enzyme. This work studies the biochemical interaction between the arginase enzyme, plant extracts, flavonoids and derivatives of caffeic acid. The acetone extract of Qualea grandiflora leaves showed higher inhibitory capacity of arginase (IC50 = 1.7 &plusmn; 01 &micro;g/mL) from the analyzed extracts. Among the flavonoids, the most potent compound was taxifolin (IC50 = 1.7 &plusmn; 0.2 &micro;M). The verbascosideo was the derivative of caffeic acid with greater potential for arginase inhibition (IC50 = 0.5 &plusmn; 0.2 &micro;M) The structures of these compounds can serve as a reference in developing new drugs for the control of leishmaniosis, which target arginase.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-01-10T10:37:22Z No. of bitstreams: 1 anacristinacapelupimendes.pdf: 1977487 bytes, checksum: 25f7b78abcedf5b1f10fe8710aebbc3e (MD5) / Approved for entry into archive by Diamantino Mayra (mayra.diamantino@ufjf.edu.br) on 2017-01-31T11:21:31Z (GMT) No. of bitstreams: 1 anacristinacapelupimendes.pdf: 1977487 bytes, checksum: 25f7b78abcedf5b1f10fe8710aebbc3e (MD5) / Made available in DSpace on 2017-01-31T11:21:31Z (GMT). No. of bitstreams: 1 anacristinacapelupimendes.pdf: 1977487 bytes, checksum: 25f7b78abcedf5b1f10fe8710aebbc3e (MD5) Previous issue date: 2015-07-31 / A contaminação de produtos alimentícios e medicinais pode ocorrer desde o cultivo até a estocagem, principalmente quando não existe controle das condições que favorecem o crescimento fúngico. O fungo Aspergillus carbonarius causa a deterioração dos produtos, além de produzir ocratoxina A, potencialmente carcinogênica e nefrotóxica. O aumento de cepas resistentes aos antifúngicos sintéticos além da diversidade de ações biológicas relacionadas às espécies vegetais Rosmarinus officinallis L. e Piper aduncum L. estimula as pesquisas científicas por novos antimicrobianos. Considerando o aumento da exposição aos agentes fúngicos, devido ao crescimento do consumo de produtos in natura, e a alta incidência de ocratoxina A, o presente trabalho teve como objetivo avaliar a ação antifúngica e antiocratoxigênica dos óleos essenciais de R. officinallis L. e P.aduncum L. sobre o fungo Aspergillus carbonarius CDCA 0126. Os óleos essenciais foram obtidos por hidrodestilação e o perfil químico determinado por cromatografia gasosa acoplada à espectrometria de massas. O efeito inibitório dos óleos essenciais sobre os isolados fúngicos foi determinado pela associação dos métodos da difusão em disco e diluição em ágar e quantificação de ocratoxina por cromatografia líquida de alta eficiência. Foram identificados como compostos majoritários verbenona (24,61%), geraniol (17,55%) e 1,8 cineol (11,26%) e no óleo de P.aduncum L., piperitona (28,17%) e limoneno (10,42%). Os ensaios in vitro demonstraram a efetividade dos óleos na inibição do crescimento fúngico. O óleo essencial de R.officinallis L. reduziu em 94,36% a produção da ocratoxina A, sendo que o óleo de P.aduncum L. inibiu totalmente a produção. Os resultados deste trabalho indicam que os óleos essenciais avaliados representam uma alternativa promissora no controle do crescimento A. carbonarius e na produção de ocratoxina A. / The contamination of food and medicinal products plants, can occur from cultivation to storage, especially when there is no control of the conditions that favor fungal growth. The fungus Aspergillus carbonarius causes deterioration of products, in addition to producing ochratoxin A, a potentially carcinogenic and nephrotoxic. The increase of synthetic antifungal resistant strains beyond the diversity of biological actions related to Rosmarinus officinalis L. plant species and Piper aduncum L. encourages scientific research for new antimicrobials. Considering the increased exposure to fungal agents, due to elevation consumption of fresh products and the high incidence of ochratoxin A, this study aimed to evaluate the antifungal action and antiochratoxigenic property of essential oils R.officinallis L. and P. aduncum L. on the fungus Aspergillus carbonarius CDCA 0126. The essential oils were obtained by hydrodistillation and the chemical profile determined by gas chromatography-mass spectrometry. The inhibitory effect of essential oils on the fungal isolate was determined by the association of disk diffusion and agar dilution methods and the quantification of ochratoxin A released by high-performance liquid chromatography. They were identified as major compounds verbenone (24.61%), geraniol (17.55%) and 1,8 cineole (11.26%) in R.officinallis L. essential oil and piperitone (28.17%) and (10.42%) P.aduncum L.. In vitro assays demonstrated the effectiveness of oil in the inhibition of fungal growth. The essential oil R.officinallis L. reduced the 94.36% the production of ochratoxin A, whereas the oil P.aduncum L. completely inhibited production. These results indicate that the evaluated essential oils represent a promising alternative for the control of A. carbonarius growth and production of ochratoxin A.

Polyketide secondary metabolites constitute a structurally-diverse and clinically-important family of natural products. The wide range of biological activities represented by these substrates have contributed to therapeutic agents with annual sales exceeding $20B USD. Large multi-domain proteins called polyketide synthases (PKSs) use simple building blocks to generate highly-oxygenated and stereochemically-rich frameworks with astonishing selectivity. These substrates often feature rigidifying biases imposed by macrocyclic lactones and substituted heterocycles, which can impact their bioactive conformation. The work of this dissertation combines synthetic chemistry and biochemistry to investigate chemoenzymatic production of macrocyclic polyketide natural products. Research focused on validating a transannular oxa-conjugate addition strategy to assembly 2,6-cis-tetrahydropyran (THP) ring systems, as demonstrated by synthesis of the macrocyclic core to neopeltolide. Ultimately, we wish to apply this chemistry to de novo PKS pathways for rapid, reliable, and sustainable production of THP-bearing products like neopeltolide, and toward building SAR libraries. Additionally, a second study probed the specificity of the macrolactonizing thioesterase (TE) domain from the 6-deoxyerythronolide B (DEBS) biosynthetic pathway. This pathway is the paradigm for type-I PKS systems, and is responsible for producing the macrolide core of erythromycin. Our on-going research evaluates the limits of promiscuity within this specific catalytic domain, to characterize the structural elements required to accurately predict macrolactonization. The long-term goal of this study is to assess the potential applicability of DEBS TE as a generalized cyclization biocatalyst for combinatorial biochemistry and chemoenzymatic research.

No description available.

Magister Scientiae - MSc / Apoptosis is a process in which a cell programmes its own death. It is a highly organized physiological mechanism in which injured or damaged cells are destroyed. Apart from physiological stimuli however, exogenous factors can induce apoptosis. Many anti-cancer drugs work by activating apoptosis in cancer cells. Natural substances have been found to have the ability to induce apoptosis in various tumour cells and these substances have been used as templates for the construction of novel lead compounds in anticancer treatment. On the other hand, alkylating agents such as cisplatin, cis- [PtCl2 (NH3) 2] have been widely used as antineoplastic agents for a wide variety of cancers including testicular, ovarian, neck and head cancers, amongst others. However, the use of cisplatin as an anticancer agent is limited due to toxicity and resistance problems. The aim of this present study was to screen the leaves of Rhus laevigata, a South African indigenous plant, for the presence of pro-apoptotic and anti-proliferative natural compounds and also to screen newly synthesised palladium based complexes (15 and 57) and a platinum based complex (58) for their antineoplastic activities tested against a panel of cell lines. Results. The results showed that crude methanol extracts from Rhus laevigata as well as the newly synthesised palladium based complexes (15 and 57) and a platinum based complex (58) induced apoptosis in the cell lines tested, as demonstrated by the externalization of phosphatidylserine, mitochondrial membrane permeabilization, caspase-3 activation, and DNA fragmentation. Caski (cervical cancer) and H157 (non small cell lung carcinoma) cell lines treated with the methanol extract from Rhus laevigata however, were more resistant to apoptosis induction. Among the metallocomplexes, complexes 15 and 57, palladium based complexes, were the most active. Conclusion The methanol extract from the leaves of Rhus laevigata contain pro-apoptotic and antiproliferative natural compound(s), which need to be characterised and elucidated as they could provide the much-needed lead compounds in the fight against cancer. On the other hand the newly synthesized palladium complexes also need further evaluation to see if they can be used as anticancer agents that can overcome the problems associated with cisplatin.