921 resultados para bioactive compounds


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Infusions and decoctions of Cymbopogon ambiguus have been used traditionally in Australia for the treatment of headache, chest infections and muscle cramps. The aim of the present study was to screen and identify bioactive compounds from C. ambiguus that could explain this plant's anti-headache activity. A dichloromethane extract of C. ambiguus was identified as having activity in adenosine-diphosphate-induced human platelet aggregation and serotonin-release inhibition bioassays. Subsequent fractionation of this extract led to the isolation of four phenylpropenoids, eugenol, elemicin, Eugenol methylether and trans-isoelemicin. While both Eugenol and elemicin exhibited dose-dependent inhibition of ADP-induced human platelet serotonin release, only eugenol displayed potent inhibitory activity with an IC(50) value of 46.6 microM, in comparison to aspirin, with an IC(50) value of 46.1 microM. These findings provide evidence to support the therapeutic efficacy of C. ambiguus in the non-conventional treatment of Headache and Inflammatory conditions.

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The plant kingdom harbours many diverse bioactive molecules of pharmacological relevance. Temperate fruits and vegetables have been highly studied in this regard, but there have been fewer studies of fruits and vegetables from the tropics. As global consumers demand and are prepared to pay for new appealing and exotic foods, tropical fruits are now being more intensively investigated. Polyphenols and major classes of compounds like flavonoids or carotenoids are ubiquitously present in these fruits, as they are in the temperate ones, but particular classes of compounds are unique to tropical fruits and other plant parts. Bioactivity studies of compounds specific to tropical fruit plants may lead to new drug discoveries, while the synergistic action of the wide range of diverse compounds contained in plant extracts underlies nutritional and health properties of tropical fruits and vegetables. The evidence for in vitro and animal bioactivities is a strong indicator of the pharmacological promise shown in tropical fruit plant biodiversity. In this review, we will discuss both the occurrence of potential bioactive compounds isolated and identified from a selection of tropical fruit plants of importance in Australia, as well as recent studies of bioactivity associated with such fruits and other fruit plant parts.

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Termites play a major role in foraging and degradation of plant biomass as well as cultivating bioactive microorganisms for their defense. Current advances in “omics” sciences are revealing insights into function-related presence of these symbionts, and their related biosynthetic activities and genes identified in gut symbiotic bacteria might offer a significant potential for biotechnology and biodiscovery. Actinomycetes have been the major producers of bioactive compounds with an extraordinary range of biological activities. These metabolites have been in use as anticancer agents, immune suppressants, and most notably, as antibiotics. Insect-associated actinomycetes have also been reported to produce a range of antibiotics such as dentigerumycin and mycangimycin. Advances in genomics targeting a single species of the unculturable microbial members are currently aiding an improved understanding of the symbiotic interrelationships among the gut microorganisms as well as revealing the taxonomical identity and functions of the complex multilayered symbiotic actinofloral layers. If combined with target-directed approaches, these molecular advances can provide guidance towards the design of highly selective culturing methods to generate further information related to the physiology and growth requirements of these bioactive actinomycetes associated with the termite guts. This chapter provides an overview on the termite gut symbiotic actinoflora in the light of current advances in the “omics” science, with examples of their detection and selective isolation from the guts of the Sunshine Coast regional termite Coptotermes lacteus in Queensland, Australia

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The first synthesis of long chain 5-n-alkylresorcinols (C15-C25) in whole grains and whole grain products by a novel modification of Wittig reaction is described. 5-n-Alkylresorcinols are phenolic lipids that have various effects on biological systems, such as antioxidant activity and interaction with biological membranes. These compounds are considered as biomarkers of whole grain intake, which is connected with reduced risk of cardiovascular diseases and certain cancers. Novel hapten derivatives of 5-n-alkylresorcinols, potential compounds for immunoanalytical techniques, are prepared by the same procedure utilizing microwave catalysed aqueous Wittig reaction as the key step. The synthesised analogues are required by various analytical, metabolism and bioactivity investigations. Four alternative strategies for producing deuterium polylabelled 5-n-alkylresorcinols are explored. Ring-labelled D3-alkylresorcinols were synthesized by acidic H/D exchange. Side chain -labelled D4-derivative was prepared by a total synthesis approach utilizing D2 deuterogenation of a D2-alkene derivative, and deuterogenation of alkynes was investigated in another total synthesis approach. An -D3-labelled alkylresorcinol is isotopically pure and completely stable under all relevant conditions encountered during analytical work. The labelling of another phenolic component of whole grains was explored. The preparation of D3-ferulic acid and related compounds by way of selective methylation of the precursors is described. The deuterated compounds are useful as standards in the quantification of these natural products in various substances, such as food and human fluids. The pure 5-n-alkylresorcinol analogues prepared were used in in vitro experiments on alkylresorcinol antioxidant activity and antigenotoxicity. The in vitro experiments show that alkylresorcinols act as antioxidants, especially when incorporated into biological systems, but possess lower activity in chemical tests (FRAP and DPPH assay). Whole grain alkylresorcinols are shown for the first time to have a protective effect against copper induced oxidation of LDL, and H2O2 or genotoxic faecal water induced damage on HT29 cells.

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Traditional Chinese medicines (TCMs), due to their long time clinic test and reliable therapeutic efficacy, are attracting increased global attention served as excellent pools of bioactive compounds for the discovery of new drugs. However, hundreds or even thousands of components are usually contained in traditional Chinese medicines and only a few compounds are responsible for the pharmaceutical and/or toxic effects. The large numbers of other components in traditional Chinese medicines make the screening and analysis of the bioactive components extremely difficult. By the way, the combination effect of bioactive components on the pharmacological activity makes it very difficult to clear the therapeutic mechanism of TCMs. Therefore, some strategies have to design for screening of bioactive compounds in traditional Chinese medicines, which further leads to disclose the therapeutic mechanism of TCMs in molecular level. The review will summarize the present state of the art of screening strategy for active compounds in traditional Chinese medicines, and the chromatography methods for screening and analysis of bioactive compounds in traditional Chinese medicines will be emphasized. (C) 2004 Elsevier B.V. All rights reserved.

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Biofingerprinting chromatogram, analysis, which is defined as the comparison of fingerprinting chromatograms of the extract of traditional Chinese medicines (TCMs) before and after the interaction with biological systems (DNA, protein. cell. etc.), was proposed for screening and analysis of the multiple bioactive compounds in TCMs. A method of microdialysis sampling combined with high performance liquid chromatography (HPLC) was applied to the study of DNA-binding property for the extracts of TCMs. Seven compounds were found to bind to calf thymus DNA (ct-DNA) from the TCMs of Coptis chinensis Franch (Coptis), but only three ones from Phellodendron amurense Rupr. (Phellodendron) and none from Sophoraflavescens Ait. (Sophora) to bind to ct-DNA. respectively. Three of them were identified as berberine, palmatine and jatrorrhizine and their association constants (K) to ct-DNA were determined by microdialysis/HPLC. Competitive binding behaviors of them to ct-DNA were also investigated. © 2005 Elsevier B.V. All rights reserved.

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Recently, new lines of yellow-seeded (CS-Y) and black-seeded canola (CS-B) have been developed with chemical and structural alteration through modern breeding technology. However, no systematic study was found on the bioactive compounds, chemical functional groups, fatty acid profiles, inherent structure, nutrient degradation and absorption, or metabolic characteristics between the newly developed yellow- and black-seeded canola lines. This study aimed to systematically characterize chemical, structural, and nutritional features in these canola lines. The parameters accessed include bioactive compounds and antinutrition factors, chemical functional groups, detailed chemical and nutrient profiles, energy value, nutrient fractions, protein structure, degradation kinetics, intestinal digestion, true intestinal protein supply, and feed milk value. The results showed that the CS-Y line was lower (P ≤ 0.05) in neutral detergent fiber (122 vs 154 g/kg DM), acid detergent fiber (61 vs 99 g/kg DM), lignin (58 vs 77 g/kg DM), nonprotein nitrogen (56 vs 68 g/kg DM), and acid detergent insoluble protein (11 vs 35 g/kg DM) than the CS-B line. There was no difference in fatty acid profiles except C20:1 eicosenoic acid content (omega-9) which was in lower in the CS-Y line (P < 0.05) compared to the CS-B line. The glucosinolate compounds differed (P < 0.05) in terms of 4-pentenyl, phenylethyl, 3-CH3-indolyl, and 3-butenyl glucosinolates (2.9 vs 1.0 μmol/g) between the CS-Y and CS-B lines. For bioactive compounds, total polyphenols tended to be different (6.3 vs 7.2 g/kg DM), but there were no differences in erucic acid and condensed tannins with averages of 0.3 and 3.1 g/kg DM, respectively. When protein was portioned into five subfractions, significant differences were found in PA, PB1 (65 vs 79 g/kg CP), PB2, and PC fractions (10 vs 33 g/kg CP), indicating protein degradation and supply to small intestine differed between two new lines. In terms of protein structure spectral profile, there were no significant differences in functional groups of amides I and II, α helix, and β-sheet structure as well as their ratio between the two new lines, indicating no difference in protein structure makeup and conformation between the two lines. In terms of energy values, there were significant differences in total digestible nutrient (TDN; 149 vs 133 g/kg DM), metabolizable energy (ME; 58 vs 52 MJ/kg DM), and net energy for lactation (NEL; 42 vs 37 MJ/kg DM) between CS-Y and CS-B lines. For in situ rumen degradation kinetics, the two lines differed in soluble fraction (S; 284 vs 341 g/kg CP), potential degradation fraction (D; 672 vs 590 g/kg CP), and effective degraded organic matter (EDOM; 710 vs 684 g/kg OM), but no difference in degradation rate. CS-Y had higher digestibility of rumen bypass protein in the intestine than CS-B (566 vs 446 g/kg of RUP, P < 0.05). Modeling nutrient supply results showed that microbial protein synthesis (MCP; 148 vs 171 g/kg DM) and rumen protein degraded balance (DPB; 108 vs 127 g/kg DM) were lower in the CS-Y line, but there were no differences in total truly digested protein in small intestine (DVE) and feed milk value (FMV) between the two lines. In conclusion, the new yellow line had different nutritional, chemical, and structural features compared to the black line. CS-Y provided better nutrient utilization and availability.

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Sweet cherries (Prunus avium L.) ‘Sweetheart’ were harvested at different production regions from Portugal (Cova da Beira and Portalegre) and Spain (Valle de Jerte). Cherries were harvested at their commercial maturation according to the empirical knowledge of external color corresponding to good quality. Fruits were stored and evaluated in order to study their quality on the harvest day and during a period of 21 days, at cold storage (1 ºC, 95% RH). The sweet cherry ‘Sweetheart’ is a well-known variety and a highly appreciated one but fruits present a short shelf life. On the other hand the effect of different “terroir” on cherry characteristics should be known and clarified. Fruits from day 0, considered without storage, were kept at 20ºC and analyzed. Every weak, 3 replicas were randomly picked up and 10 fruits from each one were submitted to several analyses after fruit temperature stabilized at 20ºC. Several quality parameters were evaluated: external colour (L*, a*, b*), texture, soluble solids content (SSC), titratable acidity (TA) and the ratio between soluble solid contents (SSC) and tritratable acidity (TA). Fruits from different orchards and locations were significantly different according to these parameters. Fruits from Cova da Beira were less firm comparing with other two regions, Valle de Jerte and Portalegre, which may indicate a higher maturation rate at harvest in those fruits. This is in accordance with SSC/titratable acidity rate suggesting a late harvest in Cova da Beira comparing with other two orchards, however fruits from Cova da Beira exhibit a poor color at harvest. These results clearly showed a lower correlation between SSC and firmness considering fruits origin.

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O vinho tinto é uma importante fonte de compostos fenólicos com atividade antioxidante e que estão relacionados com a prevenção de doenças cardiovasculares e cancro. Estes compostos são um sub-produto do processo de destilação vínica utilizado para produzir aguardente necessária para a produção de Vinho do Porto. Esta tese tem como objetivo valorizar os compostos fenólicos resultantes das destilarias de vinho, através do estudo da sua composição, das interações com o material polimérico do vinho, da sua estabilidade durante o armazenamento e avaliação dos seus potenciais efeitos biológicos in vitro. Isto irá permitir definir aplicações para estes compostos como ingredientes alimentares com propriedades funcionais. Dois vinhos tintos (RW1 e RW2) foram utilizados como fonte de compostos fenólicos. A fim de estudar estes compostos, cada vinho foi evaporado à pressão atmosférica, permitindo obter o respetivo vinho desalcolizado (DW1 e DW2). Os polissacarídeos e compostos fenólicos presentes nos vinhos desalcolizados foram fracionados por extração em fase sólida utilizando cartuchos C18 sep-pak. A fração hidrofóbica, rica em compostos fenólicos, foi separada em frações ricas em ácidos fenólicos, em procianidinas e em antocianinas, as quais foram usadas para avaliar a sua contribuição para a atividade antioxidante total e caracterização fenólica detalhada dos DW. Foram obtidas quantidades comparáveis de compostos fenólicos totais (1.3 g/L para RW1 e DW1, e 3.1 para RW2 e DW2), de taninos (1.2 g/L para RW1 e DW1 e 1.6 para RW2 e DW2) e de antocianinas (0.24 g/L para RW1 e DW1 e 0.41 para RW2 e DW2) para os vinhos e para os respetivos vinhos desalcolizados. A determinação da atividade antioxidante de RW e DW pelos métodos do DPPH e ABTS também originou valores semelhantes, permitindo inferir que o processo de destilação realizado não promoveu uma perda relevante de compostos fenólicos. A atividade antioxidante total de vinho deveu-se essencialmente à fração rica em antocianinas. Os dois DW foram dialisados para se obter o material polimérico dos vinhos (WPM1 e WPM2). O WPM1 e WPM2 apresentavam 1.1 e 1.3 g/L de material sólido, respetivamente. O WPM (WPM1 e WPM2) era composto por polissacarídeos (31 e 36%), proteínas (10 e 12%) e também por compostos fenólicos (32 e 43%). A análise de açúcares mostrou que as manoproteínas e as arabinogalactanas eram os principais polissacarídeos presentes. A extração do WPM com metanol deu origem a um material insolúvel em metanol (PMi) e a uma fração solúvel em metanol, que continuava a conter hidratos de carbono e compostos fenólicos, mostrando uma forte interação entre estes compostos. Para determinar a energia de ativação (Ea) da libertação dos compostos fenólicos de fracções de material polimérico do vinho, foram realizadas diálises do DW, WPM e PMi, utilizando-se quatro concentrações diferentes, a cinco temperaturas (5-40 °C). O valor da Ea foi 25 para o WPM e 61 kJ/mol para o PMi, mostrando que os compostos fenólicos do vinho podem estar associados de forma diferente à matriz polimérica e que uma fração pode estar, ainda, fortemente associada a esta matriz. A fim de avaliar a possível existência de interações seletivas com os compostos fenólicos, o WPM foi fracionado, permitindo a obtenção de uma fração rica em manoproteínas (MP), através de uma cromatografia de afinidade com concanavalina A e 3 frações ricas em arabinogalactanas (AG0, AG1 e AG2) obtidas por cromatografia de troca aniónica. Foi avaliada a difusão de nove antocianinas monoméricas através de uma membrana de diálise, em presença do WPM, e das frações ricas em MP e em AG. A diálise dos compostos fenólicos livres do vinho foi realizada como ensaio em branco. Todas as frações poliméricas mostraram capacidade para reter as antocianinas, embora em diferente extensão. Foi observada uma capacidade de retenção maior para as antocianinas acilglucosiladas do que para as antocianinas glucosiladas. A fração rica em AG teve uma maior contribuição para a capacidade de retenção das antocianinas pelo material polimérico vinho do que a fração rica em MP, principalmente quando as antocianinas estavam acetiladas. Com o objetivo de estudar formas para preservar, a longo prazo, as propriedades antioxidantes dos compostos fenólicos, o extrato de compostos fenólicos (PCE), em pó, foi armazenado em diferentes condições de luz e atmosfera, à temperatura ambiente durante 1 ano. Observou-se que o PCE armazenado no escuro, dentro de um exsicador sob atmosfera de azoto, preservou 95% da atividade antioxidante inicial. Também foram avaliadas as melhores condições para preservar as antocianinas quando em solução, armazenadas a duas temperaturas (5 e 30 ºC) durante 3 meses. A adição de 0.5 g/L de uma fração rica em polissacarídeos a um vinho armazenado a 30 ºC promoveu a proteção das antocianinas, especialmente das antocianinas cumaroiladas. Os potenciais efeitos biológicos dos compostos fenólicos foram avaliados em diferentes sistemas celulares in vitro utilizando as seguintes frações: WPM, WPS (polissacarídeos do vinho), WPC (compostos fenólicos do vinho), PA-E (fração rica em ácidos fenólicos), PR-E (fração rica em procianidinas) e APP-E (fração rica em antocianinas e procianidinas poliméricas). Foi observada uma maior viabilidade celular quando as células do carcinoma do cólon HT-29 foram expostas a dois agentes oxidantes (radiação UV e H2O2) em presença das frações PR-E e APP-E. Além disso, os extratos WPS, WPC, PR-E e APP-E mostraram propriedades anti-inflamatórias, avaliadas pela inibição da produção de NO por células de macrófagos RAW264.7, sendo o extrato APP-E (0.19 mg/mL) o que exibiu a maior capacidade anti-inflamatória. A fim de elucidar as propriedades antioxidantes dos extratos do vinho em células humanas, os glóbulos vermelhos (RBC) foram selecionados como um modelo metabolicamente simples. Os extratos WPM, WPS, WPC, PR-E, e APP-E mostraram efeito anti-hemolítico para a hemólise dos RBC provocada pelo peróxido de hidrogénio (H2O2) e pelo di-hidrocloreto de 2,2'-azo-bis(2-diaminopropano) (AAPH). Os resultados obtidos permitem concluir que o processo de desalcoolização dos vinhos à pressão atmosférica, preservou as principais características antioxidantes dos compostos fenólicos. Estes compostos podem contribuir para a defesa das células contra agentes oxidantes, nomeadamente por terem um potencial de atividades anti-inflamatória e anti-hemolítica, promovendo a viabilidade celular. A interação dos compostos fenólicos do vinho com o material polimérico permite inferir uma dosagem contínua e gradual das antocianinas vinho tinto após a sua ingestão, contribuindo para um período mais longo da sua exposição e, como consequência, dos seus potenciais benefícios para a saúde.

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Tese de dout., Química, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2008

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A discussion of the most interesting results obtained in our laboratories, during the supercritical CO(2) extraction of bioactive compounds from microalgae and volatile oils from aromatic plants, was carried out. Concerning the microalgae, the studies on Botryococcus braunii and Chlorella vulgaris were selected. Hydrocarbons from the first microalgae, which are mainly linear alkadienes (C(23)-C(31)) with an odd number of carbon atoms, were selectively extracted at 313 K increasing the pressure up to 30.0 MPa. These hydrocarbons are easily extracted at this pressure, since they are located outside the cellular walls. The extraction of carotenoids, mainly canthaxanthin and astaxanthin, from C. vulgaris is more difficult. The extraction yield of these components at 313 K and 35.0 MPa increased with the degree of crushing of the microalga, since they are not extracellular. On the other hand, for the extraction of volatile oils from aromatic plants, studies on Mentha pulegium and Satureja montana L were chosen. For the first aromatic plant, the composition of the volatile and essential oils was similar, the main components being the pulegone and menthone. However, this volatile oil contained small amounts of waxes, which content decreased with decreasing particle size of the plant matrix. For S. montana L it was also observed that both oils have a similar composition, the main components being carvacrol and thymol. The main difference is the relative amount of thymoquinone, which content can be 15 times higher in volatile oil. This oxygenated monoterpene has important biological activities. Moreover, experimental studies on anticholinesterase activity of supercritical extracts of S. montana were also carried out. The supercritical nonvolatile fraction, which presented the highest content of the protocatechuic, vanilic, chlorogenic and (+)-catechin acids, is the most promising inhibitor of the enzyme butyrylcholinesterase. In contrast, the Soxhlet acetone extract did not affect the activity of this enzyme at the concentrations tested. (C) 2011 Elsevier B.V. All rights reserved.

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The effect of organic and conventional agricultural systems on the physicochemical parameters, bioactive compounds content, and sensorial attributes of tomatoes (‘‘Redondo’’ cultivar) was studied. The influence on phytochemicals distribution among peel, pulp and seeds was also accessed. Organic tomatoes were richer in lycopene (+20%), vitamin C (+30%), total phenolics (+24%) and flavonoids (+21%) and had higher (+6%) in vitro antioxidant activity. In the conventional fruits, lycopene was mainly concentrated in the pulp, whereas in the organic ones, the peel and seeds contained high levels of bioactive compounds. Only the phenolic compounds had a similar distribution among the different fractions of both types of tomatoes. Furthermore, a sensorial analysis indicated that organic farming improved the gustative properties of this tomato cultivar.

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Microalgae are promising microorganisms for the production of food and fine chemicals. Several species of microalgae are used in aquaculture with the purpose of transfer bioactive compounds up to the aquatic food chain. The main objective of this project was to develop a stress–inducement strategy in order to enhance the biochemical productivity of Nannochloropsis gaditana, Rhodomonas marina and Isochrysis sp. for aquaculture purposes having in account their growth and organizational differences. In this regard, two experiments were design: the first one consisted on the alteration of overall nutrient availabilities in growth medium; and the second one comprised changes in nitrogen and sulfur concentrations maintaining the concentrations of the other nutrients present in a commercial growth medium (Nutribloom plus), which is frequently used in aquaculture. Microalgae dried biomass was characterized biochemically and elemental analysis was also performed for all samples. In first experimental design: linear trends between nutrient availability in growth media and microalgae protein content were obtained; optimum productivities of eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) were attained for both R. marina and N. gaditana in growth media enriched with 1000 L L-1 of nutrient solution whereas for Isochrysis sp. the double of Nutribloom plus was needed; the decrease of glucans and total monosaccharides with nutrient availability for R. marina and Isochrysis sp. showed the occurrence of a possible depletion of carbohydrates towards lipids and proteins biosynthesis. Second experimental desing: N. gaditana exhibited the highest variation in their biochemical composition against the applied perturbation; variations observed for microalgae in their biochemical composition were reflected in their elemental stoichiometry; in N. gaditana the highest nitrogen concentrations lead to overall maximum productivities of the biochemical parameters. The results of the present work show two stress-inducement strategies for microalgae that may constitute a base for further investigations on their biochemical enhancement.

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Eight tropical fruit pulps from Brazil were simultaneously characterised in terms of their antioxidant and antimicrobial properties. Antioxidant activity was screened by DPPH radical scavenging activity (126–3987 mg TE/100 g DW) and ferric reduction activity power (368–20819 mg AAE/100 g DW), and complemented with total phenolic content (329–12466 mg GAE/100 g DW) and total flavonoid content measurements (46–672 mg EE /100 g DW), whereas antimicrobial activity was tested against the most frequently found food pathogens. Acerola and açaí presented the highest values for the antioxidant-related measurements. Direct correlations between these measurements could be observed for some of the fruits. Tamarind exhibited the broadest antimicrobial potential, having revealed growth inhibition of Pseudomonas aeruginosa. Escherichia coli, Listeria monocytogenes, Salmonella sp. and Staphylococcus aureus. Açaí and tamarind extracts presented an inverse relationship between antibacterial and antioxidant activities, and therefore, the antibacterial activity cannot be attributed (only) to phenolic compounds.