Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Este trabalho descreve o estudo fitoquÃmico de Licania rigida (Chrysobalanaceae), conhecida popularmente por oiticica. Neste estudo foram utilizadas as cascas e lenho das raÃzes, o lenho do caule, folhas e flores. Os extratos obtidos foram submetidos à partiÃÃo lÃquido-lÃquido, cromatografias convencionais (adsorÃÃo e exclusÃo) e modernas Cromatografia LÃquida de Alta eficiÃncia (CLAE). A investigaÃÃo quÃmica da raiz de L. rigida resultou no isolamento dos compostos: esqualeno (LR-01), lupeol (LR-02), Ãcido betulÃnico (LR-03), niruriflavona (LR-11) e a mistura binÃria dos esterÃides, β-sitosterol e estigmasterol glicosilados (LR-06). Do caule resultou no isolamento do Ãcido licÃnico (LR-09), enquanto das folhas isolou-se o α-tocoferol (LR-07), a mistura binÃria do α-tocoferol e α-tocotrienol (LR-08), a mistura binÃria dos esterÃides β-sitosterol e estigmasterol (LR-05), os flavonÃides: afzelina (LR-12), miricetina-3-raminosÃdeo (LR-15) e o miricetina-3-glicosÃdeo (LR-16). Das flores foram isolados os compostos: canferol (LR-10), tilirosÃdeo (LR-13), licanolina (LR-14) e o diterpeno 1β,16α,17-trihidroxi-ent-caurano (LR-04). Esta investigaÃÃo quÃmica resultou no isolamento de substÃncias inÃditas para a literatura, bem como para a espÃcie e o gÃnero. A determinaÃÃo estrutural dos compostos isolados foi obtida pela anÃlise dos espectros de ressonÃncia magnÃtica nuclear de hidrogÃnio-1 e carbono-13 uni e bidimensionais, espectros de massa obtidos por Impacto EletrÃnico (EM-IE) e IonizaÃÃo por electronSpray (EM-ESI) e os espectros de infravermelho (IV), bem como atravÃs da comparaÃÃo com os dados da literatura. / This work describes the phytochemical study of Licania rigida (Chrysobalanaceae), popularly known as oiticica. In this study we used the bark and wood of roots, woody stem, leaves and flowers. The extracts were subjected to liquid-liquid partition chromatography, conventional (adsorption and exclusion) and modern, high performance liquid chromatography (HPLC). The chemical investigation of the root of L. rigida resulted in the isolation of compounds: squalene (LR-01), lupeol (LR-02), betulinic acid (LR-03), niruriflavone (LR-11) and the binary mixture of steroids, β-sitosterol and stigmasterol glycoside (LR-06). From stem was isolated the acid licanic (LR-09), while from leaves were isolated the following metabolites: α-tocopherol (LR-07), the binary mixture of α-tocopherol and α-tocotrienol (LR-08), the mixture binary steroid β-sitosterol and stigmasterol (LR-05) and the flavonoids afzelin (LR- 12), myricetin-3-ramnoside (LR-15) and myricetin-3-glucoside (LR-16). From flowers were isolated the followed compounds: kaempferol (LR-10), tiliroside (LR-13), licanolin (LR-14) and the diterpene 1β,16α,17-trihydroxy-ent-kaurane (LR-04). This chemical investigation resulted in the isolation of novel substances for literature, the species and Licania genus. Structure determination of isolated compounds was obtained by analysis of nuclear magnetic resonance spectra of a hydrogen-1 and carbon-13 one and two dimensional, mass spectra obtained by electron impact (MS-IE) and electronSpray ionization (ESI-MS) and Infrared spectra (IR) and by comparison with literature data.

The sea conceals a mermaid’s grotto of useful chemicals-marine natural products of therapeutic potential. Marine sponges in particular are a rich source of natural products with structural diversity and novel biological activity. In recent times, there has been a growing interest in the synthesis of marine natural products. The present thesis entitled, “Synthesis of bioactive marine meroterpenoids: frondosins and liphagal” is an endeavor along the same lines and is organized under two parts –Part A and Part B. Part A: Studies towards the total synthesis of (±) frondosins A and B Frondosins A-E are IL-8 inhibiting marine meroterpenoids, with novel bicyclo[5.4.0]undecane framework, exhibiting anti-inflammatory and anti HIV-1 activities. A relatively simple and inherently flexible ring-closing metathesis (RCM) based strategy was employed to achieve the total synthesis of frondosins A (formal) and B in only 17 linear steps (total 13 operations) and 5% overall yield. A concise route, based on RCM, to the core structure of bioactive frondosins is amenable to ready appendage diversification and enables implementation of functionalization manoeuvres on all positions in the seven-membered ring of the bicyclic framework was also developed. A Diels-Alder strategy that led to the synthesis of 8-des-methyl norfrondosin A dimethyl ether is also delineated in Part A of the thesis. Part B: A concise synthesis of (±) liphagal Liphagal is a marine meroterpenoid displaying an unprecedented “liphagane” skeleton. It is a selective inhibitor of PI3K  and significantly toxic against a small panel of human tumor cell lines (LoVo, CaCo-human colon and MDA-468-human breast). A concise and straightforward biomimetic strategy towards liphagal and its 14-des-formyl analogue that awarded liphagal dimethyl ether in only eight steps from commercially available building blocks is described in Part B of the thesis.

No description available.

Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Honeybush tea, also known as “South Africa’s sweetest tea”, is a herbal tea made from the leaves and twigs of Cyclopia spp., indigenous to the fynbos biome in the Western and Eastern Cape provinces of South Africa. The pleasant sweet aroma and taste of fermented honeybush, its low tannin content and the absence of caffeine have led to widespread interest in the commercial cultivation and processing of honeybush tea since the mid-1990s. Although more than 20 species of honeybush grow in the wild, only a few species are commercially exploited for the manufacture of tea. Currently the more prominent species are C. intermedia, C. subternata, C. genistoides, and C. sessiliflora. The present research contributes to a comprehensive honeybush research programme being conducted at the Agricultural Research Council (ARC) Infruitec-Nietvoorbij in South Africa. The first phase of the present study, using C. genistoides as representative species, was aimed at developing the necessary methodology for the analysis of extremely low concentrations of honeybush volatiles. A high-capacity headspace sample enrichment probe was applied successfully in conjunction with gas chromatography-mass spectrometry (GC-MS) to analyse the volatile organic compounds present in dry or infused unfermented and fermented honeybush. A total number of 255 volatile compounds were identified in unfermented and fermented honeybush, the majority of which are terpenoids (138; 54%) comprising mostly terpenes, terpene ketones, terpene alcohols and terpene ethers. Of the other compound classes, the aldehydes are the largest group, followed by esters, hydrocarbons and ketones. The stereochemistry of the identified compounds was determined whenever possible. This is the most comprehensive chemical characterisation of the volatile compounds in a South African herbal plant reported to date. A comparative study of green and fermented honeybush showed that the same compounds are, to a large extent, present in both, albeit in different relative concentrations. Not all of the identified honeybush volatiles are necessarily odour-active compounds contributing to the overall typical honeybush aroma. An important aspect of this research was thus the identification of the 46 odour-active compounds in fermented honeybush by means of gas chromatography-olfactometry (GC-O), using detection frequency and aroma extract dilution analysis methods. Fifteen of these compounds, mainly terpenoids, were singled out as the most intense individual contributors to the honeybush aroma based on consideration of all the relevant GC-O data. The odours of certain compounds, i.e. (6E,8Z)-megastigma-4,6,8-trien-3-one, (6E,8E)-megastigma- 4,6,8-trien-3-one, (7E)-megastigma-5,7,9-trien-4-one, 10-epi- -eudesmol, epi- -muurolol and epi- - cadinol, were perceived by GC-O assessors as typically honeybush-like. The quantitative GC-MS data of seven different Cyclopia samples (including four different species and variants thereof) were compared with respect to all the volatile components and particularly with respect to the odour-active compounds. Interesting variations were found in the concentrations of certain odour-active compounds in the various samples. The quantitative data obtained for the odour-active honeybush volatiles and data obtained from the sensory analysis of eight Cyclopia samples (including four different species and variants thereof) were subjected to statistical analysis and interesting associations between compounds with certain sensory aroma attributes were established. The present study has made a major contribution to the scientific knowledge regarding one of South Africa’s most popular indigenous herbal teas. / AFRIKAANSE OPSOMMING: Heuningbostee, wat ook bekend staan as “Suid-Afrika se soetste tee”, word gemaak van die blare en takkies van Cyclopia spp. wat inheems is en voorkom in die fynbosbioom van die Wes- en Oos-Kaapprovinsies van Suid-Afrika. Die aangename soet smaak en aroma van gefermenteerde heuningbos, die lae tannnien-inhoud en die feit dat die tee kafeïenvry is, het gelei tot belangstelling in die kommersiële verbouing en prosessering van heuningbostee gedurende die 1990s. Meer as 20 heuningbosspesies kom in die natuur voor, maar slegs ‘n paar spesies word kommersieel verbou vir die vervaardiging van heuningbostee waarvan C. intermedia, C. subternata, C. genistoides en C. sessiliflora tans die belangrikste spesies is. Die navorsing maak deel uit van ‘n omvattende heuningbos navorsingsprogram wat onder leiding staan van die Landbounavorsingsraad Infruitec- Nietvoorbij in Suid-Afrika. In die eerste fase van die huidige studie is die nodige analitiese metodologie ontwikkel vir die monsterneming en analise van die vlugtige organiese verbindings wat in uiters lae konsentrasies in heuningbos voorkom, deur van ‘n verteenwoordigende spesie, C. genistoides, gebruik te maak. ‘n Sogenaamde “sample enrichment probe” (SEP) is ontwikkel en suksesvol in kombinasie met gaschromatografie-massaspektrometrie (GC-MS) aangewend vir die analise van die vlugtige verbindings aanwesig in die bodamp van sowel droë plantmateriaal as infusies van ongefermenteerde en gefermenteerde heuningbos. ‘n Totaal van 255 vlugtige verbindings is geïdentifiseer, waarvan die meeste hoofsaaklik terpenoïede is (138, 54%) en terpene, terpeenketone, terpeenalkohole en terpeeneters insluit. Die ander verbindingsgroepe, waarvan die aldehiede die grootste groep is, sluit in esters, koolwaterstowwe en ketone. Indien haalbaar, is die stereochemie van die geïdentifiseerde verbindings ook bepaal. Hierdie studie is die mees omvattende chemiese karakterisering van die vlugtige verbindings in ‘n Suid-Afrikaanse kruieplant wat tot dusver onderneem is. ‘n Vergelykende studie het getoon dat ongefermenteerde en gefermenteerde heuningbos tot ‘n groot mate dieselfde verbindings, hoewel in verskillende relatiewe konsentrasies, bevat. Nie al die geïdentifiseerde vlugtige verbindings in heuningbos is noodwendig aroma-aktiewe verbindings wat ‘n bydrae tot die algehele tipiese heuningbosaroma lewer nie en daarom was die identifisering van die 46 aroma-aktiewe verbindings in geferementeerde heuningbos deur gebruik te maak van gaschromatografie-olfaktometrie (GC-O) deur middel van deteksiefrekwensie en aroma ekstrak verdunningsanalise, ‘n belangrike aspek van die navorsing. Na oorweging van al die tersaaklike GC-O data is 15 van hierdie verbindings, hoofsaaklik terpenoïede, uitgesonder as die verbindings wat die belangrikste bydrae tot die heuningbosaroma lewer. Die reuke van sekere van die verbindings, nl. (6E,8Z)-megastigma-4,6,8-triën-3-oon, (6E,8E)-megastigma-4,6,8-triën-3-oon, (7E)-megastigma-5,7,9-triën-4-oon, 10-epi- -eudesmol, epi- -muurolol, en epi- -cadinol, is deur sommige van die GC-O paneellede as tipies heuningbosagtig beskryf. Die kwantitatiewe GC-MS data van sewe verskillende Cyclopia monsters (insluitende vier verskillende spesies en variante daarvan) is vergelyk met betrekking tot al die vlugtige verbindings, asook veral met betrekking tot die aroma-aktiewe verbindings. Interessante variasies in die konsentrasies van sekere aroma-aktiewe verbindings is in die verskillende monsters waargeneem. Die kwantitatiewe data van die aroma-aktiewe heuningbosverbindings en data verkry uit die sensoriese analise van agt Cyclopia monsters (insluitende vier verskillende spesies en variante daarvan), is onderwerp aan statistiese analises waaruit interessante assosiasies tussen verbindings met sekere sensoriese aroma-eienskappe waargeneem is. Hierdie studie lewer ‘n groot bydrae tot die wetenskaplike kennis aangaande een van Suid- Afrika se mees populêre inheemse kruietees.

A própolis é uma mistura complexa de substâncias com aspecto resinoso, elaborada majoritariamente por Apis mellifera. Possui composição química diversificada, que varia de acordo com a flora ao redor da colmeia. Os objetivos deste trabalho são a caracterização química de quatro própolis de diferentes localidades do Brasil (MG, CE, PR e SC) e o isolamento e testes das atividades antioxidante (métodos do DPPH e β-caroteno) e anti-HIV (atividade inibitória da transcriptase reversa) das substâncias presentes nestas amostras. A fração volátil da própolis verde de Viçosa (MG) foi extraída e analisada por CG-EM. Verificou-se a presença de mono- e sesquiterpenos e ácidos fenólicos, sendo este o primeiro relato da presença do ledeno, muuroladieno, β-copaeno, aloaromadendreno e nerolidol na fração volátil da própolis verde brasileira. Um de seus constituintes majoritários, o éster alílico do ácido 3-prenilcinâmico foi isolado e testado quanto às atividades biológicas, apresentando alta ação antioxidante no método do β-caroteno. Nos demais testes o éster não foi ativo. Sugere-se que esta falta de atividade está ligada à ausência de hidroxilas fenólicas livres nesta substância. As amostras do CE, PR e SC foram analisadas por várias técnicas cromatográficas, incluindo CLAE-EM-EM, e colorimétricas. A própolis do CE, com origem botânica desconhecida, possui flavonoides (ex. naringenina e isoramnetina) e ácidos fenólicos (ex. cafeico e ρ-cumárico). Sua composição química é diferente daquela previamente descrita para uma própolis do mesmo estado. Os flavonoides pinocembrina e galangina, típicos da própolis europeia, foram detectados na própolis de SC, sugerindo que a origem botânica desta própolis seja Populus deltóide, descrita anteriormente como fonte de resinas para própolis da região. A própolis do PR não possui esses flavonoides, e é composta por ácidos fenólicos altamente prenilados. Sua composição é diferente daquelas já descritas, sugerindo uma nova fonte de resina para as própolis do sul do Brasil. Estas três própolis foram submetidas ao isolamento biomonitorado de seus constituintes, sendo obtidas 19 substâncias, nove delas com alta ação antioxidante, uma com ação anti-HIV, e três com ação anti-HIV moderada. Sugere-se que a atividade antioxidante destas própolis seja conferida pelos seus componentes majoritários, como o ácido p-cumárico, presente nas três própolis; quercetina, isoraminetina e 7,4\',5\'-trimetilmiricetina-5,3\'-dihidroxi-3-O-cafeoil glucosídeo, na própolis do CE; a mistura dos ácidos diidrocafeoilquinico + dimetoxicinamoil-diidrocafeoilquinico, na própolis do PR; ácido cafeico, pinocembrina e uma substância desconhecida, identificada como 16, na própolis de SC. Substâncias com ação anti-HIV foram isoladas das própolis do CE (naringenina, isoraminetina e quercetina) e PR (ácido 4-acetil-5-carboxi cumárico), demonstrando que estas própolis possuem grande potencial na busca de substâncias ativas / Propolis is a complex mixture of substances with resinous aspect, prepared mostly by Apis mellifera honeybees. It has a diverse chemical composition, according to the flora around the hive. The aims of this work are to chemically characterize four samples of propolis from different regions of Brazil (MG, CE, SC and PR states) and to isolate and test the antioxidant (DPPH and β-carotene methods) and anti-HIV (inhibitory activity of HIV-1 reverse transcriptase) activities of the compounds present on those samples. The volatile fraction sample of green propolis from Viçosa (MG) was extracted and analyzed by GC-MS. We verified the presence of mono-and sesquiterpenes and phenolic acids. Among them ledene, muuroladiene, β-copaene, aloaromadendrene and nerolidol were detected for the first time in the volatile fraction of Brazilian green propolis. One of its major constituents, the allyl ester of 3-prenylcinnamic acid was isolated and tested for biological activities. It was shown to have high antioxidant activity by the β-carotene method, but showed no activity regarding the other tests. It is suggested that the lack of activity is linked to the absence of free phenolic hydroxyl on the compound. The samples from CE, PR and SC states were analyzed by various chromatographic, including HPLC-MS-MS, and colorimetric techniques. The sample from CE, with unknown resin source, contains flavonoids (eg, naringenin and isorhamnetin) and phenolic acids (e.g. ρ-coumaric acid and caffeic). Its chemical composition is different from a previously described sample from the same state. The flavonoids galangin and pinocembrin, typical from European propolis, were detected in the sample from SC, which suggests that its botanical source is Populus deltoide. The sample from PR does not have these flavonoids; instead it possesses prenylated phenolic acids. Its composition is different from samples previously described, suggesting that the sample corresponds to a new type of propolis from southern Brazil. The three propolis samples were subjected to bioguided isolation of their constituents. Nineteen substances were obtained, nine of them with high antioxidant activity, one with anti-HIV action, and three with moderate anti-HIV activity. It is suggested that the antioxidant activity of these propolis is conferred by their major constituents, such as p-coumaric acid, present in all three samples, quercetin, isorhaminetin and 7,4\',5\'-trimethylmyricetin-5,3\'-dihydroxy-3-O-caffeoyl glucoside in propolis from CE; a mixture of dihydrocaffeoylquinic and dimethoxycinnamoyl-dihydrocaffeoylquinic acids in propolis from PR; and caffeic acid, pinocembrin and a unknown compound named 16, in propolis from SC. Compounds with anti-HIV activity were isolated from propolis from CE (naringenin, quercetin and isorhaminetin) and PR (4-acetyl-5-carboxy-coumaric acid), indicating that these types of propolis have high potential in the search for active compounds

Made available in DSpace on 2015-04-22T22:02:15Z (GMT). No. of bitstreams: 1 Edinilze Souza Coelho Oliveira.pdf: 4961035 bytes, checksum: f6de1b94d1c9a5c50a72d78882119b88 (MD5) Previous issue date: 2012-09-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Leishmaniasis is considered by the World Health Organization as one of the most severe infections, due to have high capacity to produce deformities. The existing drugs are highly toxic and the parasites have been showed resistance to these drugs. Scientific researches have been proven the antiparasitic potential of extracts and compounds isolated from plant species. The subject of this work is to obtain essential oils from leaves of three species of from Myrtaceae: Eugenia patrisii, Marlierea umbraticola and Myrciaria floribunda, two species from Myristicaceae: Virola mollissima and V. theiodora, one specie from Annonaceae: Bocageopsis multiflora and one specie from Lauraceae: Endlicheria bracteolata, collected at the Adolpho Ducke Forest Reserve, Manaus, AM. The collections were performed in two periods: winter (April) and summer (September). The analysis of essential oils of E. patrisii, M. floribunda, B. multiflora and V. mollissima by GC-MS showed a high percentageof sesquiterpenes, while oils M. umbraticola and V. theiodora presented the monoterpenes as main constituents. The essential oil of the fresh leaves from E. bracteolata presented a differential when extracted in the month of April. There was observed the precipitate during the extraction and when analyzed by GC-MS showed a chromatographic profile of about 73.7% oxygenated sesquiterpenes. However, the oil of the dry season showed the hydrocarbons sesquiterpene as major constituents. The solid material obtained from E. bracteolata was purified, and guaiol was identified by MS, NMR and comparison with the literature data. The study with the heartwood from V. mollissima led to obtain a precipitate of the hexane extract and isolation of neolignans carinatin and dehydrodieugenol. Concerning the pharmacological tests, essential oils and extracts of low polarity were tested on the promastigotes of Leishmania amazonensis. In this context, the oil V. mollissima showed highr activity (IC50 of 19.7g/mL). The neolignan carinatina showed lower activity with value IC50 of 53.9g/mL. The essential oils from B. multiflora and M. umbraticola were the most active with IC50 of 14.8 and 21.1g/mL, respectively. The extracts that showed highest activity on promastigotes from L. amazonensis were subjected to the cytotoxicity analysis in non-infected macrophages, and oil from V. mollissima was the most toxic with IC50 of 17.16g/mL 10 compared to standard pentamidine (IC50 = 24.40 g/mL), while the oil from B. multiflora showed less toxicity with IC50 = 42.71g/mL. When evaluated against brine shrimp Artemia salina, all the oils exhibited high toxicity compared to standard lapachol (LC50 = 10.47g/mL), being the essential oil from E. bracteolata the most toxic with LC50 of 0.53g/mL. The antioxidant activity evaluation against the radical free DPPH below 28% of activity to the essential oils. In contrast, the neolignan deidrodieugenol and precipitate obtained from V. mollissima, exhibit high antioxidant activity with IC50=10.68 and IC50=6.87g/mL, respectively. / A leishmaniose é considerada pela Organização Mundial de Saúde como uma das mais graves infecções existentes, por causa da sua alta capacidade de produzir deformidades. Os medicamentos existentes são de elevada toxicidade e o parasita tem apresentado resistência a esses medicamentos. Pesquisas científicas tem comprovado o potencial antiparasitário de extratos e substâncias isoladas de espécies vegetais. Este trabalho teve como objetivo principal a obtenção de óleos essenciais das folhas de três espécies da família Myrtaceae: Eugenia patrisii, Marlierea umbraticola e Myrciaria floribunda, duas espécies da família Myristicaceae: Virola mollissima e V. theiodora, uma espécie da família Annonaceae: Bocageopsis multiflora e uma espécie da família Lauraceae: Endlicheria bracteolata, ocorrentes na Reserva Florestal Adolpho Ducke, Manaus, AM. As coletas foram realizadas em dois períodos correspondentes ao inverno (abril) e verão (setembro). As análises dos óleos essenciais de E. patrisii, M. floribunda, B. multiflora e V. mollissima por CG-EM evidenciaram alta porcentagem de sesquiterpenos, enquanto que os óleos de M. umbraticola e V. theiodora apresentaram monoterpenos como constituintes majoritários. Já o óleo essencial das folhas frescas de E. bracteolata apresentou um diferencial quando extraído no mês de abril. Um precipitado foi observado durante a extração e quando analisado por CG-EM apresentou um perfil cromatográfico com cerca de 73,7% de sesquiterpenos oxigenados. Entretanto, o óleo da estação seca apresentou sesquiterpenos hidrocarbonetos como constituintes principais. O material sólido obtido de E. bracteolata foi purificado, e o guaiol foi identificado por EM, RMN e comparação com dados descritos da literatura. O estudo com o cerne de V. mollissima levou a obtenção de um precipitado do extrato hexano e ao isolamento das neolignanas carinatina e deidrodieugenol. Concernente aos ensaios farmacológicos, os óleos essenciais e extratos de baixa polaridade foram testados frente às formas promastigotas de Leishmania amazonensis. Nesse contexto, o óleo de V. mollissima exibe maior atividade (CI50 de 19,7 g/mL) e a neolignana carinatina apresenta menor atividade com valor de CI50 de 53,9 g/mL. Em relação aos óleos das demais espécies, os 8 óleos essenciais de B. multiflora e de M. umbraticola foram os mais ativos com CI50 de 14,8 e 21,1 g/mL, respectivamente. Os extratos que demonstraram maior atividade sobre as formas promastigotas de L. amazonensis foram submetidos ao ensaio de citotoxicidade em macrófagos não parasitados, sendo o óleo de V. mollissima o mais tóxico com CI50 de 17,16 g/mL em comparação ao padrão pentamidina (CI50 = 24,40 g/mL), enquanto que o óleo de B. multiflora apresentou menos toxicidade com CI50 de 42,71g/mL. Quando avaliados frente ao microcrustáceo Artemia salina, todos os óleos apresentaram elevada toxicidade em relação ao padrão lapachol (CL50 =10,47g/mL), sendo o óleo essencial de E. bracteolata o mais tóxico com CL50 de 0,53g/mL. A avaliação da atividade antioxidante frente ao radical livre DPPH demonstrou que os óleos apresentaram atividade abaixo de 28%. Em contrapartida, a neolignana deidrodieugenol e o precipitado obtido de V. mollissima, apresentam atividade bastante pronunciada com CI50=10,68 e CI50=6,87 g/mL, respectivamente. Palavras-chave: Óleos essenciais, análise cromatográfica, leishmaniose,

Nature’s expertise in creating breathtaking structural wonders which are vital for sustenance of life on this planet has astonished and inspired many synthetic chemists. We too have been attracted towards understanding, exploring and mimicking a few of these magnificent molecular entities. Our efforts are directed towards the synthesis of two types of molecular assembles of contemporary interest; first of them are medium ring carbohydrate mimetics which are unnatural compounds inspired by Nature and other class consisted of the terpenoid natural products which are conceived and assembled by Nature in ever increasing numbers. The spectacular development of carbohydrate mimetics, prompted primarily by their properties as glycosidase inhibitors, has led to the conception and synthesis of a wide variety of novel structures, the most significant ones belonging to the families of imino sugars and carbasugars. Major advances in diverse subjects such as chemical synthesis, analytical chemistry, structural biology, cell-surface recognition, molecular modeling and spectroscopy have made carbohydrate mimetics embraced by scientific community with increasing vigor. A major area of interest of organic chemistry is the total synthesis of complex natural products conceived and created by Nature. As a result of refinements in isolation and purification techniques and recent advances in spectroscopy and crystallography, unravelling of natural products from exotic species such as wild plants to microorganisms and from geographic locations ranging from mountain tops to the ocean floors, has made identification and structural elucidation of complex natural products a fairly routine exercise. Among natural products, terpenoids are considered as masterpieces of structural diversity with their bewildering carbocyclic arrangements and diverse functionalities embedded in them. The present thesis entitled “Synthesis of medium ring carbasugar analogues and terpenoid natural products” is an effort to design and synthesise natural and unnatural molecular entities either conceived by human mind or inspired by Nature. The research described in this thesis has been organized under three chapters. Chapter I: Design and synthesis of cyclooctanoid and cyclononanoid carbasugar analogues. Chapter II: A total synthesis of putative structure of sesquiterpenoid natural product dichomitol. Chapter III: A total synthesis of diterpenoid natural product guanacastepene C. A brief overview of each of these three chapters is presented below.(For Equations and Figures Refer PDF File) Chapter I: Design and synthesis of cyclooctanoid and cyclononanoid carbasugar analogues In recent years, the search for new therapeutically useful glycosidase inhibitors, mimicking carbohydrates 1, has extended beyond the realm of five and six membered cyclitols 2 (carbasugars), and targeted towards the medium-sized carbocyclic cores. In this context, we have conceptulised a new family of novel cyclooctanoid 3 and cyclononanoid 4 carbasugar analogues in order to study the effect of the enhanced flexibility and of new spatial distribution displayed by these structures on their adaptability in the active site of the enzymes. We have developed a versatile synthesis of cyclooctane based polyols 3 from commercially available hydrocarbon cyclooctatetraene 5. It was visualised that a bicyclo[4.2.1]nona-2,4,7-trien-9-one 6 is a functionally locked cyclooctatetraene with dispensed and differentiated double bonds and a masked C9 cycloocta-carbasugar from which the eight membered ring can be extracted through oxidative C1-C9 bond scission, Scheme 1. Several transformations in 6, leading to a range of polyhydroxylated cyclooctanoids was envisaged. Bayer-villiger oxidation in ketone 6 was smooth and led to a δ-lactone which on catalytic OsO4 dihydroxylation furnished diol 7. Further acetylation on 7 delivered a rearranged γ-lactone 8. LAH reduction in 8 and peracetylation furnished diene 9. Controlled catalytic hydrogenation in 8 furnished 1:1 mixture of 10 and 11, which on hydride reduction gave tetrols 12 and 13, respectively, Scheme 2. Protection of vic diol in 12 led to 14. Hydroboration-oxidation of 14 and peracetylation furnished three diastereomeric mixture of acetonide triacetates in 9:4:1 ratio and they were hydrolysed to give 15-17, Scheme 3. Interestingly, pentahydroxy 16 is an eight membered analogue of α-talose. Reagents and conditions: i) m-CPBA, DCM, 60% ii) OsO4, NMMO, acetone-H2O, 75% iii) Ac2O, Py, 90% iv) LAH, THF v) Ac2O, Py, 36% (2 steps) vii) H2, Pd/C, EtOAc, 95% viii) LAH, THF, 40%. Reagents and conditions: i) acetone, amberlyst-15, 80% ii) BH3-THF, NaOH, H2O2 iii) Ac2O, Py, 54% (2 steps) iv) 2N, HCl, 76%. Acetylation of 12 led to tertraacetate 18 which on OsO4-dihydroxylation and acetylation furnished two diastereomeric hexaacetates in 1:1 ratio. Hydrolysis of these hexaacetates with base furnished 19-20, Scheme 4. Reagents and conditions: i) Ac2O, Py, 90% ii) OsO4, NMMO, acetone-H2O iii) Ac2O, Py, 72% (2 steps) iv) NaOMe, MeOH, 75%. Diene 9 on exhaustive stereoselective double dihydroxylation and base hydrolysis led to octahydroxycyclooctane 21, Scheme 5. A cyclooctane derivative bearing eight oxygen atoms has been prepared for the first time. Reagents and conditions: i) OsO4, NMMO, acetone-H2O ii) NaOMe, MeOH, 56% (2 steps). In an unconventional but interesting enterprise, commercially available hydrocarbon cyclooctatetraene 5 has been elaborated to a rare hexose sugar (DL)-β-allose and its 2C branched analogue. The main theme in this approach was to generate a cyclic acetal moiety, a structural characteristic of sugars through ozonolytic cleavage of an appropriately crafted olefin and in situ intramolecular acetalisation, Scheme 6. Acetonide protection in 7 led to 22. LAH reduction in 22 liberated the diol and selective primary alcohol protection as TBS derivative furnished 23. Ozonolysis of 23 and PCC oxidation of the resulting lactal 24 led to lactone 25. Methoxide mediated lactone opening in 25 and protection of anomeric hydroxyl group as methyl ether led to 26. LAH reduction of ester led to 27 and further deprotections furnished (DL)-methyl-2-deoxy-2C-hydroxymethyl-β-allose 28. Protected hexose homologue 27 was converted via a mesylate to the terminal olefin 29 through a series of functional group transformations. Ozonolysis of 29 furnished hemiacetal 30, which on sodium borohydride reduction and acetonide deprotection delivered (DL)-methyl-β-allopyranoside 31, Scheme 7. Motivated and encouraged by the synthesis of cyclooctane carbasugar analogues, it was decided to venture into the synthesis of cyclononane carbasugar analogues. It was visualized that appropriately functionalized bicyclo[4.3.1]decane system 32, can serve as a masked C10 cyclononane carbasugar from which the nine membered ring can be extracted through the C1-C10 bond scission, Scheme 8. Reagents and conditions: i) 2,2-DMP, CSA, 65% ii) LAH, THF, 80% iii) TBSCl, imidazole, 54% iv) O3, DCM-MeOH, DMS v) PCC, DCM, 40% (2 steps) vi) NaOMe, MeOH vii) MeI, Ag2O, 73% (2 steps) viii) LAH, THF, 85% ix) TBAF, THF, 70% x) amberlyst-15, MeOH, 65% xi) Ac2O, DMAP, 92% xii) TBAF, THF, 74% xii) MsCl, DCM, 65% xiv) KOtBu, DMSO, 70% xv) O3, DCM, 75% xvi) NaBH4, MeOH, 80% xvii) amberlyst-15, MeOH, 60%. The bridged dienone 32 was readily prepared from cyclohexanone following a literature protocol. Ketone 32 on Bayer-Villiger oxidation furnished lactone 33 in moderate yield, and further exhaustive double dihydroxylation furnished two unanticipated rearranged products δ-lactone 34 and γ-lactone 35 in 5:3 ratio. Both, the novel lactones 34 and 35 were further elaborated to the corresponding hexahydroxy cyclononane carbasugar analogues 36 and 37, Scheme 9. These novel medium ring carbasugar analogues involving a nine memebered carbocycle have been synthesized for the first time. Reagents and conditions: i) m-CPBA, DCM, 60% ii) OsO4, NMMO, acetone-H2O, 54% of 34 and 32% of 35 iii) acetone, PPTS, 98% iv) LAH, THF, 90% v) 2N HCl, 88% vi) acetone, PPTS, 92% vii) LiBH4, THF, 50% viii) 2N HCl, 88%. All the details of our synthetic efforts towards several novel carbasugar analogues which have been synthesised for the first time, along with the synthesis of some interesting polyoxygenated carbocyclic intermediates, unusual products from rearrangements, incisive NMR studies and X-ray analyses to solve the stereochemical puzzles, along with enzyme inhibition studies will be presented in this chapter of the thesis. Chapter II: A total synthesis of putative structure of sesquiterpenoid natural product Dichomitol This chapter describes the first total synthesis of the putative structure of the sesquiterpenoid natural product dichomitol 55 bearing a novel triquinane framework, and reported in 2004 from the bascidiomycete fungi Dichomitus squalens by a group of Chinese researchers. Dichomitol 55 not only represented a novel skeletal-type among linear triquinanes but was also biogenetically quite intriguing as it was suggested to be related to hirsutanes through an unusual methyl shift. This unusual positioning of methyl group in Reagents and conditions: i) CO(OCH3)2, THF, 82% ii) MeI, THF, 90% iii) ethanedithiol, PTSA, 75%, iv) Raney-Ni, EtOH, 90% v) PCC, DCM, 90% vi) LHMDS, THF, -78 °C; Pd(OAc)2, CH3CN, 86% vii) MeLi, ether viii) PCC, DCM, 84% (2 steps) ix) Mg, 4-bromobutene, CuBr-DMS, THF; AcOH, 95% x) LHMDS, THF, -78 °C; Pd(OAc)2, CH3CN, 80% xi) DBU, KOtBu, PTSA, RhCl3. dichomitol 55 which probably originated through a Wagner-Meerwein rearrangement of a corresponding ceratopicane derivative aroused our interest, curiosity (and suspicion) towards this natural product and it was decided to undertake its total synthesis. Our synthesis commenced from the known bicyclic ketone 39 readily accessible from commercially available 1,5-cyclooctadiene 38 through a sequence previously developed in our laboratory. Successive α- carbomethoxylation and α-methylation correctly installed C-11 centre in 40. Carbonyl group in 40 was protected as its thioketal to furnish 41 which on reductive desulphurization with simultaneous benzyl deprotection and further oxidation led to ketone 42. Following Saegusa protocol, 42 was converted into enone 43. Alkylative transposition in 43 furnished enone 44, which on Cu(I) mediated 1,4-conjugate addition delivered 45 with desired methyl stereochemistry with preferred addition from the exo-face. Kende cyclization in 45 smoothly delivered tricyclic 46, a C5-C6 double bond isomer of the desired tricyclic precursor of the natural product. Several attempts to isomerise the C5-C6 double bond in 46 to the required C6-C7 position failed to deliver 47, Scheme 11. Reagents and conditions: i) ethyleneglycol, PTSA, C6H6, 97% ii) LAH, THF, 96% iii) amberlyst-15, acetone, 95% iv) TBSCl, imidazole, DCM, 98% v) OsO4, NMMO, acetone-H2O, 90% vi) TBSCl, imidazole, DCM, 86% vii) IBX, DMSO-toluene, 78% viii) LHMDS, THF, -78 °C, 40% ix) Martin sulfurane, CHCl3, 40% x) DIBAL-H, DCM, 90% xi) TBAF, THF, 85%. At this stage it was decided to pursue an aldol based approach as it may help to install the tetrasubstituted C6-C7 double bond. Bicyclic ketone 45 was protected as its ethylene ketal, ester group was reduced with LAH and ketal deprotection furnished 48. The primary hydroxyl protection in 48 led to 49. Dihydroxylation on the butenyl arm gave diol 50, wherein the primary hydroxyl was protected as TBS derivative and secondary hydroxyl group was oxidized to furnish 51. Employing LHMDS as a base, key aldol reaction was carried out on 51 to give three aldol products in which the required compound 52 was the major product. The tertiary hydroxyl group in 52 when subjected to dehydration using Martin sulfurane delivered the required 53 with correctly installed C6-C7 double bond, only in trace amounts, along with two other regioisomeric dehydration products. DIBAL-H reduction on 53 stereoselectively delivered 54 and TBS deprotection furnished a product 55 bearing the structure assigned for the natural product ‘dichomitol’, Scheme 12. Significant variation in the spectral characteristics of our synthetic product 55 and those reported for ‘dichomitol’ necessitates a reinvestigation of the structure of natural product. All the details of our synthetic efforts, problems and challenges encountered enroute and the synthetic insights used to address them will be presented in this chapter of the thesis. Chapter III: A total synthesis of diterpenoid natural product Guanacastepene C This chapter describes the first total synthesis of a novel 5,7,6 fused tricyclic diterpenoid natural product guanacastepene C 71 isolated from an unidentified fungus growing on the tree Daphnopsis americana by Clardy in 2001. Besides guanacastepene C 71, fourteen other guanacastepenes A-O have also been isolated and these compounds have evoked unprecedented attention from the synthetic community. In particular, several Reagents and conditions: i) LAH, THF, 55% ii) a. PMBCl, THF, 67% b. TBSOTf, DCM, 68% c. DDQ, DCM-H2O, 95% iii) IBX, toluene-DMSO, 92% iv) Ph2POCH2COCH2COOEt, THF, 86% v) H2, Pd/C, EtOAc, 99% vi) a. 6N H2SO4, THF-H2O, 80% b. 2,2-DMP, PPTS, 91% vii) PCC, DCM, 80% viii) DBU, C6H6, 82% guanacastepenes exhibit antibacterial activity against MRSA and VREF. Several total syntheses of guanacastepenes have been reported in the last two years due to their enticing architecture and promising biological activity profile. Our group has also been in the fray and following the early leads, we embarked on an ambitious journey towards the total synthesis of guanacastepene C 71. The synthetic approach towards guanacastepene C 71, envisaged in this study, was revealed through a retrosynthetic analysis which identified hydroazulene core 57, bearing AB rings of the natural product as an advanced precursor on which ring ‘C’ could be annulated, Scheme 13. Earlier efforts from our group have demonstrated that AB ring precursor 57 can be elaborated from readily available tri-cylcopentadienone 56. Keto-ester in 57 on LAH reduction led to diol 58 and following a three step protocol of protection-deprotection led to 59 wherein the free primary hydroxyl was oxidized to furnish the required aldehyde 60. It was condensed with appropriate four carbon Horner-Wittig partner to furnish a mixture of keto-enol tautomers 61. Hydrogenation of trans double bond led to 62 and TBS deprotection and concomitant acetonide deprotection followed by acetonide protection furnished the hemiketal 63. PCC oxidation in 63 furnished tricyclic precursor 64 for the key Knoevenagel cyclization. Exposing 64 to DBU delivered 65 embodying complete tricarbocyclic framework of guanacastepene C, Scheme 14. LAH reduction on 65, was stereoselective and led predominantly to the unrequired α- isomer 66. Reagents and conditions: i) LAH, THF, -78 °C, 65% ii) PPh3, C6H5COOH, DIAD, THF, 78% iii) LAH, THF, 84% iv) Ac2O, DCM, 90% v) 4N H2SO4, THF-H2O, 44% vi) DDQ, THF, 85% vii) K2CO3, MeOH, 70%. Diol 66 was subjected to standard Mitsunobu protocol to furnish dibenzoate 67 which was hydrolysed and reprotected as diacetate 68 with the desired 5β stereochemistry. Deprotection of acetonide in 68 led to the diol 69. Chemoselective allylic oxidation of vicinal diol employing DDQ furnished guanacastepene C diacetate 70. Finally, careful base hydrolysis of 70 delivered guanacastepene C 71, Scheme 15. Synthesis of guanacastepene C was a difficult and often frustrating journey. Many trials and tribulations to overcome the synthetic challenges and our persistant and sincere efforts to overcome the hurdles confronted by us during the synthesis and finally attainment of the first total synthesis of guanacastepene C 71 will be the subject matter of the last chapter of this thesis.(For structural formula pl refer pdf file)

The focus of this thesis was to study the chemotaxonomic relationship of selected southern Australian marine brown algae of the genera Cystophora and Sargassum. Consequently, this resulted in the isolation and structure elucidation of six new terpenoids from two southern Australian marine brown algae Cystophora moniliformis and Sargassum fallax together with 10 previously reported natural products. As a result of the re-isolation of these known secondary metabolites, updated and complete structural characterisation data could be provided for the first time for 7 of these compounds. Chemotaxonomic studies of Cystophora moniliformis resulted in the isolation of two new cyclic epimeric terpene diols moniliforminol A (3.25) and moniliforminol B (3.26), a new linear farnesyl acetone derivative (3.27) and the previously described terpenoids (3.19)-(3.24). This study also resulted in the first complete 2D NMR characterisation for compounds (3.21) to (3.24) as well as the first report of (3.24) occurring as a natural product. All structures were elucidated by detailed spectroscopic analysis with the relative configurations of (3.25) and (3.26) being established by selective 1D nOe NMR experiments. The proposed biosynthetic pathway for the above compounds has also been described. Chemical investigation of the Southern Australian marine brown alga Sargassum fallax resulted in the isolation of three new meroditerpenoids fallahydroquinone (4.8), fallaquinone (4.9) and fallachromenoic acid (4.10), together with the previously reported compounds sargaquinone (4.1) (isolated and identified in a mixture with sargaquinoic acid), sargahydroquinoic acid (4.2), sargaquinoic acid (4.3) and sargachromenol (4.11). As a result of this study the complete 2D NMR characterisation for sargahydroquinoic acid (4.2) and sargaquinoic acid (4.3) could also be reported for the first time. All structures were elucidated by detailed spectroscopic analysis. Sargahydroquinoic acid (4.2) and sargaquinoic acid (4.3) displayed moderate antitumour activity.

This study has aimed to evaluate the effects of treatments with essential oil (OAT) and infusion of Aloysia triphylla (IAT) on microbiological, chemical and sensory stability of silver catfish (Rhamdia quelen). α-citral (29.4%) and β-citral (20.8%) were the main components of OAT, followed by limonene (11.9%). Major compounds identified in the IAT were isoquercetrin > rosmarinic acid > luteolin. Experiments were divided in four parts in which the first has was aimed at evaluating the antimicrobial activity of OAT against foodborne bacteria strains, the microbiological stability of silver catfish fillets refrigerated after dipping in OAT solution and the microbiological changes during the ice storage of whole silver catfish previously sedated with OAT during the transport in vivo. In vitro assays revealed that the OAT has strong inhibitory activity against Staphylococcus aureus and Enterococcus faecalis, and moderate inhibitory activity against Escherichia coli, Enterobacter aerogenes, Salmonella Typhimurium, Salmonella Choleraesuis and Salmonella Enteritidis, but does not inhibit Pseudomonas aeruginosa. Fillets imersed in 30 or 40 μL/L of OAT had lower mesophilic and psychrotrophic counts than control (p<0.05) during storage. Entire refrigerat fish that were previously sedated with 40 μL/L of OAT slowed lower counts for psychrotrophic at the 7th and 28th days of storage than control (p<0.05), whereas the mesophilic counts were similar to the control during storage. The 2nd experiment has aimed at determine whether the use of OAT in the water (0, 30 or 40 μL/L) to sedate silver catfish during transport action would delay the chemical and the sensory post mortem changes of refrigerated whole fish. Fresheness of entire silver catfish was extented by sedation with 40 μL/L of OAT as indicated by the delay in the onset of rigor mortis and in the degradation of inosine 5'-monophosphate into inosine compared to the control (p<0.05). Fish exposed to 30 or 40 μL/L OAT received lower demerit scores than the control (p <0.05) in sensory evaluation after 10 days of storage, whereas fish treated with 40 μL/L of OAT had higher shelf life (35 days in ice) than the control (p<0.05). In the 3rd experiment, we assessed whether the use of OAT in the water to sedate silver catfish during transport would influence the lipid stability of fish fillets during frozen storage (17 months). The fillets from fish exposed to 30 and 40 μL/L of OAT had higher initial content of primary products of lipid oxidation (conjugated dienes, CD) than control fillets, whereas the fillets from fish exposed to 40 μL/L of OAT had lower content of secondary products of lipid oxidation (thiobarbituric acid reactive substances, TBARS) after 6, 9 and 17 months of frozen storage than control fillets (p<0.05). The 4th experiment was aimed at evaluating the in vitro antioxidant activity of IAT and the lipid stability and instrumental color of frozen fillets after immersion in distilled water (control) or IAT (1, 2.5 or 5%). The antioxidant effect of IAT (1-5%) was demonstrated as the treated fillets had lower CD values after 7 months of storage, as well as lower TBARS value than control after 4, 7 and 10 months of storage. Regardeless of the storage time, the treatment with 5% IAT reduced brightness, increased the yellowness and chroma compared to control fillets, whereas the treatment with 2.5% IAT only increased the yellowness. However, the total color change during the storage of fillets treated with 2.5 and 5% IAT was lower than in control fillets (p <0.05). These results indicate that OAT has antimicrobial activity against foodborne bacteria. Furthermore, the use of OAT as a sedative in the transport of silver catfish extended the freshness and increased shelf life of the refrigerated whole fish, and also delayed lipid oxidation of the fillets during frozen storage. Dipping silver catfish fillets in IAT delayed lipid oxidation and color changes during frozen storage, which can extend the shelf life of fillets. These results indicate the great potential of A. triphylla in the fish processing sector as a pre-slaughter treatment (sedative) or in the post-slaughter period (natural food additive). / O objetivo deste estudo foi avaliar os efeitos do óleo essencial de Aloysia triphylla (OAT) e da infusão de A. triphylla (IAT) na estabilidade da carne de jundiá (Rhamdia quelen) com ênfase nas alterações microbiológicas, químicas e sensoriais do pescado. O α-citral (29,4%) e o β-citral (20,8%) foram os compostos majoritários do OAT, seguidos do limoneno (11,9%). Na IAT foram identificados como compostos majoritários a isoquercetrina > ácido rosmarínico > luteolina. No 1º experimento avaliou-se a atividade antimicrobiana do OAT contra cepas isoladas de alimentos, a estabilidade microbiológica de filés refrigerados após imersão em solução de OAT, bem como as alterações microbiológicas durante a armazenagem sob refrigeração de jundiás inteiros previamente sedados com OAT durante o transporte in vivo. Os ensaios in vitro revelaram que o OAT apresenta ação inibidora forte contra Staphylococcus aureus e Enterococcus faecalis, e moderada contra Escherichia coli, Enterobacter aerogenes, Salmonella Typhimurium, Salmonella Choleraesuis e Salmonella Enteritidis, mas não inibe Pseudomonas aeruginosa. Os filés imersos em OAT 30 ou 40 μL/L apresentaram menores contagens de micro-organismos mesófilos e psicrotróficos que o controle (p<0,05) ao longo do armazenamento. Os peixes sedados com 40 μL/L de OAT durante o transporte tiveram contagens de psicrotróficos menores que o controle após 7 e 28 dias (p<0,05), enquanto as contagens de mesófilos foram semelhantes ao controle durante o armazenamento. No 2º experimento foi investigado se o uso do OAT na água (0, 30 ou 40 μL/L) como sedativo durante o transporte de jundiás pode retardar as modificações químicas e sensoriais do pescado inteiro refrigerado. A exposição do jundiá a 40 μL/L de OAT durante o transporte retardou o início do rigor mortis, bem como a degradação de inosina 5´-monofosfato em inosina comparado ao controle (p<0,05), prolongando o frescor do pescado. Os peixes expostos a 30 ou 40 μL/L de OAT receberam menor escore sensorial de demérito que o controle (p<0,05) após 10 dias de armazenamento, enquanto os expostos a 40 μL/L de OAT apresentaram maior vida útil (35 dias em gelo) que o controle (p<0,05). No 3º experimento foi avaliado se o uso do OAT na água como sedativo durante o transporte de jundiás influencia a estabilidade lipídica dos filés do pescado durante o congelamento. A exposição 30 e 40 μL/L de OAT resultou em maior teor inicial de produtos primários da oxidação lipídica (dienos conjugados, DC) nos filés, enquanto os filés dos peixes expostos a 40 μL/L de OAT apresentaram menor teor de produtos secundários da oxidação lipídica (substâncias reativas ao ácido tiobarbitúrico, TBARS) que os peixes controle após 6, 9 e 17 meses de congelamento (p<0,05). No 4º experimento avaliou-se a atividade antioxidante da IAT in vitro e a estabilidade lipídica e cor instrumental de filés congelados após a imersão em água destilada (controle) ou IAT (1, 2,5 ou 5%). O efeito antioxidante da IAT (1-5%) foi constatado pelos menores valores DC após 7 meses de congelamento, bem como valor de TBARS inferior ao controle após 4, 7 e 10 meses de congelamento nos filés tratados. Independente do tempo de armazenagem, o tratamento com IAT 5% reduziu a luminosidade, aumentou a tendência ao amarelo e o croma comparado aos filés controle, enquanto o tratamento com IAT 2,5% aumentou apenas a tendência ao amarelo. No entanto, a variação total de cor dos filés tratados com IAT 2,5 e 5% ao longo do congelamento foi menor que nos filés controle (p<0,05). Os resultados indicam que o OAT possui atividade antimicrobiana contra patógenos e micro-organismos indicadores de qualidade dos alimentos. Além disso, a utilização do OAT como um sedativo na água de transporte de jundiás prolongou o frescor e aumentou a vida útil do pescado inteiro refrigerado, além de retardar a oxidação lipídica dos filés durante o armazenamento congelado. A imersão de filés de jundiás na IAT retardou a oxidação lipídica e as mudanças na coloração durante o armazenamento congelado, podendo estender a vida útil dos filés. Estes resultados indicam o grande potencial da A. triphylla na área de processamento pescados, tanto no tratamento pré-abate (sedativo) como pós-abate (aditivo alimentar natural).

A própolis é uma mistura complexa de substâncias com aspecto resinoso, elaborada majoritariamente por Apis mellifera. Possui composição química diversificada, que varia de acordo com a flora ao redor da colmeia. Os objetivos deste trabalho são a caracterização química de quatro própolis de diferentes localidades do Brasil (MG, CE, PR e SC) e o isolamento e testes das atividades antioxidante (métodos do DPPH e &beta;-caroteno) e anti-HIV (atividade inibitória da transcriptase reversa) das substâncias presentes nestas amostras. A fração volátil da própolis verde de Viçosa (MG) foi extraída e analisada por CG-EM. Verificou-se a presença de mono- e sesquiterpenos e ácidos fenólicos, sendo este o primeiro relato da presença do ledeno, muuroladieno, &beta;-copaeno, aloaromadendreno e nerolidol na fração volátil da própolis verde brasileira. Um de seus constituintes majoritários, o éster alílico do ácido 3-prenilcinâmico foi isolado e testado quanto às atividades biológicas, apresentando alta ação antioxidante no método do &beta;-caroteno. Nos demais testes o éster não foi ativo. Sugere-se que esta falta de atividade está ligada à ausência de hidroxilas fenólicas livres nesta substância. As amostras do CE, PR e SC foram analisadas por várias técnicas cromatográficas, incluindo CLAE-EM-EM, e colorimétricas. A própolis do CE, com origem botânica desconhecida, possui flavonoides (ex. naringenina e isoramnetina) e ácidos fenólicos (ex. cafeico e &rho;-cumárico). Sua composição química é diferente daquela previamente descrita para uma própolis do mesmo estado. Os flavonoides pinocembrina e galangina, típicos da própolis europeia, foram detectados na própolis de SC, sugerindo que a origem botânica desta própolis seja Populus deltóide, descrita anteriormente como fonte de resinas para própolis da região. A própolis do PR não possui esses flavonoides, e é composta por ácidos fenólicos altamente prenilados. Sua composição é diferente daquelas já descritas, sugerindo uma nova fonte de resina para as própolis do sul do Brasil. Estas três própolis foram submetidas ao isolamento biomonitorado de seus constituintes, sendo obtidas 19 substâncias, nove delas com alta ação antioxidante, uma com ação anti-HIV, e três com ação anti-HIV moderada. Sugere-se que a atividade antioxidante destas própolis seja conferida pelos seus componentes majoritários, como o ácido p-cumárico, presente nas três própolis; quercetina, isoraminetina e 7,4\',5\'-trimetilmiricetina-5,3\'-dihidroxi-3-O-cafeoil glucosídeo, na própolis do CE; a mistura dos ácidos diidrocafeoilquinico + dimetoxicinamoil-diidrocafeoilquinico, na própolis do PR; ácido cafeico, pinocembrina e uma substância desconhecida, identificada como 16, na própolis de SC. Substâncias com ação anti-HIV foram isoladas das própolis do CE (naringenina, isoraminetina e quercetina) e PR (ácido 4-acetil-5-carboxi cumárico), demonstrando que estas própolis possuem grande potencial na busca de substâncias ativas / Propolis is a complex mixture of substances with resinous aspect, prepared mostly by Apis mellifera honeybees. It has a diverse chemical composition, according to the flora around the hive. The aims of this work are to chemically characterize four samples of propolis from different regions of Brazil (MG, CE, SC and PR states) and to isolate and test the antioxidant (DPPH and &beta;-carotene methods) and anti-HIV (inhibitory activity of HIV-1 reverse transcriptase) activities of the compounds present on those samples. The volatile fraction sample of green propolis from Viçosa (MG) was extracted and analyzed by GC-MS. We verified the presence of mono-and sesquiterpenes and phenolic acids. Among them ledene, muuroladiene, &beta;-copaene, aloaromadendrene and nerolidol were detected for the first time in the volatile fraction of Brazilian green propolis. One of its major constituents, the allyl ester of 3-prenylcinnamic acid was isolated and tested for biological activities. It was shown to have high antioxidant activity by the &beta;-carotene method, but showed no activity regarding the other tests. It is suggested that the lack of activity is linked to the absence of free phenolic hydroxyl on the compound. The samples from CE, PR and SC states were analyzed by various chromatographic, including HPLC-MS-MS, and colorimetric techniques. The sample from CE, with unknown resin source, contains flavonoids (eg, naringenin and isorhamnetin) and phenolic acids (e.g. &rho;-coumaric acid and caffeic). Its chemical composition is different from a previously described sample from the same state. The flavonoids galangin and pinocembrin, typical from European propolis, were detected in the sample from SC, which suggests that its botanical source is Populus deltoide. The sample from PR does not have these flavonoids; instead it possesses prenylated phenolic acids. Its composition is different from samples previously described, suggesting that the sample corresponds to a new type of propolis from southern Brazil. The three propolis samples were subjected to bioguided isolation of their constituents. Nineteen substances were obtained, nine of them with high antioxidant activity, one with anti-HIV action, and three with moderate anti-HIV activity. It is suggested that the antioxidant activity of these propolis is conferred by their major constituents, such as p-coumaric acid, present in all three samples, quercetin, isorhaminetin and 7,4\',5\'-trimethylmyricetin-5,3\'-dihydroxy-3-O-caffeoyl glucoside in propolis from CE; a mixture of dihydrocaffeoylquinic and dimethoxycinnamoyl-dihydrocaffeoylquinic acids in propolis from PR; and caffeic acid, pinocembrin and a unknown compound named 16, in propolis from SC. Compounds with anti-HIV activity were isolated from propolis from CE (naringenin, quercetin and isorhaminetin) and PR (4-acetyl-5-carboxy-coumaric acid), indicating that these types of propolis have high potential in the search for active compounds