Browsing by Author "Barroso, Marisa"
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- Antioxidant activity of decoctions of Centaurea paniculata L. and Helichrysum stoechas L. MoenchPublication . Barroso, Marisa; Fernandes, Ângela; Carvalho, Ana Maria; Ferreira, Isabel C.F.R.Ethnobotanical surveys conducted in Northeastern Portugal have documented the use of Decoctions prepared with flowering aerial parts of Centaurea paniculata L. (starthistles, knapweeds; port. escalabiosa) for inflammation and Helichrysum stoechas (L.) Moench (shrubby everlasting; port. douradinha) for the respiratory system and to reduce fever [1], from the Asteraceae botanical family. Although antioxidant properties of those plants have been investigated [2-4], there are no reports on its most used form, the decoction. Therefore, in the present work, decoctions of inflorescences and leafy flowering stems of the two mentioned species were prepared and submitted to evaluation of antioxidant potential. Four different in vitro assays were performed: scavenging effects on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals, reducing power (measured in Folin Ciocalteu and ferricyanide Prussian blue assays), inhibition of 13-carotene bleaching and inhibition of lipid peroxidation in brain cell homogenates by TBARS (thiobarbituric acid reactive substances) assay. Thedecoction of H. stoechas revealed higher antioxidant activity (lower EC50 values) than C. paniculata in all the tested assays. Data obtained could provide scientific evidence for some folk uses in the treatment of diseases related to the production of reactive species and oxidative stress, but further experiments are required to explore the mechanisms of action.
- Antioxidant profile of Stevia rebaudiana Bertoni cultivated in Portugal and submitted to different conservation conditionsPublication . Barroso, Marisa; Barros, Lillian; Rodrigues, M.A.; Sousa, Maria João; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.The demand for natural sweeteners has been gaining more and more importance due to the great controversy associated with the use of some synthetic sweeteners as cyclamates, aspartame and acesulfame-K. The steviol glycosides (E 960) are a group of natural sweeteners of generalized use; these compounds are obtained from Stevia rebaudiana Bertoni, a sweet plant native from South America (Carocho et al., 2015). However, Stevia rebaudiana Bertoni may have other uses to be exploited, in particular due to its antioxidant capacity. This plant is already produced in Portugal but it is important to evaluate if the plant chemical composition is maintained regardless of culture conditions. Therefore, in this study, stevia samples were cultivated in Braganca (northeastern of Portugal) in a field trial with defined culture conditions. After harvesting, the plants were submitted to two different treatments: kept fresh by freezing (-20°C) and oven-dried (30°C). The antioxidant profile of the samples was studied through evaluation of free radicals scavenging activity, reducing power, phenolic compounds (HPLC-DAD-ESI/MS), tocopherols (HPLC-fluorescence) and free sugars (HPLC-RI). Significant differences were observed: while oven-dried samples showed the highest antioxidant activity and phenolic compounds concentration (mainly 5-O-caffeoylquinic acid and 3,5-O-dicaffeoylquinic acid), the frozen fresh samples had the highest values of total tocopherols and total sugars. These results confirm that the plants grown in Bragança have excellent bioactive secondary metabolites responsible for the observed antioxidant capacity.
- Assessment of the nitrogen fertilization effect on bioactive compounds of frozen fresh and dried samples of Stevia rebaudiana BertoniPublication . Barroso, Marisa; Martins, Natália; Barros, Lillian; Antonio, Amilcar L.; Rodrigues, M.A.; Sousa, Maria João; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.The present study aims to assess the effect of different nitrogen (N) rates on the chemical composition and antioxidant properties of stevia frozen fresh and dried leaves, and to define the best growing conditions to maximize the levels of bioactive compounds. In general, processing affects more significantly the tocopherol and sugar contents than N fertilization. The most abundant sugars were xylose, arabinose + fructose and sucrose, presenting dried samples with higher contents than frozen fresh ones, while the latter better retained tocopherols than dry samples. Regarding phenolic compounds, greater levels were found in dried samples and in those fertilized with 25 kg N ha −1 . Leaves from plants fertilized with 25 and 50 kg N ha −1 also evidenced higher antioxidant activity, which seemed to be influenced by the phenolic composition. In general, N fertilization provides an improvement in the chemical composition and bioactive potential of stevia leaves.
- Effect of nitrogen, phosphorus, potassium and boron fertilizers on essential oils yield in lemon verbena (Alyosia triphylla)Publication . Barroso, Marisa; Arrobas, Margarida; Rodrigues, M.A.; Sousa, Maria JoãoEssential oils (EO) are liquid mixtures of volatile compounds obtained from aromatic plants. They constitute what is called the "essence" of a plant and usually have pleasantly scented fragrances[1]. The chemical composition of the EO extracted from Lemon verbena [Aioysia triphylla (L'Her) Britton], has been frequently studied because the aerial parts of this plant are used in folk medicine. Lemon verbena is an herbal species indigenous to South America which was introduced into Europe at 17th century[2]. it has been cultivated mainly due to the lemon-like aroma and utilized for herbal tea, which is reputed to have antispasmodic, antipyretic, sedative and digestive properties[3). The aim of this study was to determine the accumulation of EO in Lemon verbena growth under different fertilizer regimes of nitrogen (N), phosphorus (P), potassium (K) and boron (B). All the nutrients were applied as liquid organic fertilizers. The nutrient solution was applied in soil surface through the holes made in the anti-weeds plastic mulch by where the plants grow. The nutrients were applied at the rates: 0, 37.5, 75 and 112.5 kg N ha·•; 0, 37.5 and 75 kg P P s ha·1; 0, 37.5 and 75 kg ~0 ha·1; and 0. 75 and 1.5 kg B ha·•. The total rates of fertilizers were fractionated into three applications during the growing season. The experimental design included three replications of all fertilizer treatments. Field samples, 5 to 6 individual plants were collected, weighed and dried. The determination of the EO yield was performed by the hydro-distilled process. The plant material was subjected to extraction for 3 h using a Clevenger-type apparatus. The results here presented should be considered preliminary. However, it seems that the increase in biomass due to the increasing rates of N, P and B decreased the oil content in the plant. ForK treatment, that relationship was not found. The high oil yields were found from the samples coming from the most productive plots.
- Estabelecimento de concentrações críticas de indicadores de estado nutricional de plantas aromáticas e medicinais.Publication . Rodrigues, M.A.; Freitas, Sara L.; Ferreira, Isabel Q.; Sousa, Maria João; Barroso, Marisa; Arrobas, MargaridaAs plantas aromáticas e medicinais (PAM), tal como todas as outras culturas, respondem â aplicação de fertilizantes. Para se estabelecerem planos de fertilização racionais é necessário o diagnóstico prévio da fertilidade do solo e do estado nutricional das plantas. Contudo, para muitas PAM não existem normas de interpretação dos resultados da análise de tecidas vegetais. Neste trabalho apresentam-se algumas nuvens de pontos que relacionam indicadores de estado nutricional das plantas e g produção de biomassa com vista a, num futuro próximo, serem estabelecidos níveis críticos e intervalos de suficiência consolidados. Os resultados aqui apresentados destinam-se a divulgar as metodologias que estão a ser usadas e níveis críticos preliminares para alguns indicadores de estado nutritivo selecionados. A informação apresentada foi obtida em ensaios de campo com erva-cidreira [Melissa officinalis) e lúcia-lima (Aloysia citrodora) integradas em ensaios de fertilização com vários níveis de aplicação de azoto (N), fósforo (P), potássio (K) e boro (B). Assim, neste exercício, podem indicar-se como limites criticas preliminares para a en/a-cidreira e para os diferentes indicadores do estado nutricional os valores: N nas folhas, 34 g kg"1; valores- SPAD (SPAD-502 Plus), 33; NDVI (FieldScout CM 1000), 0, 88. Para a lúcia-lima indicam-se os valores: N nas folhas, 25 g kg"1; valores SPAD, 33; NDVI, 0, 82.
- Exploring the antioxidant potential of Helichrysum stoechas (L.) Moench phenolic compounds for cosmetic applications: chemical characterization, microencapsulation and incorporation into a moisturizerPublication . Barroso, Marisa; Barros, Lillian; Dueñas, Montserrat; Carvalho, Ana Maria; Santos-Buelga, Celestino; Fernandes, Isabel P.; Barreiro, M.F.; Ferreira, Isabel C.F.R.The present work explores the antioxidant potential of Helichrysum stoechas (L.) Moench phenoliccompounds for cosmetic applications involving the following steps: chemical characterization, microen-capsulation and incorporation into a moisturizer. Eighteen different phenolic compounds were identifiedin flowering aerial parts (decoction and hydroalcoholic extract), being 3,5-O-dicaffeoylquinic acid andmyricetin O-acetylhexoside the most abundant phenolic acid and flavonoid, respectively. Compara-tively to the decoction form, the hydroalcoholic extract presented both higher antioxidant activity andhigher phenolic content, being its lyophilized form chosen to proceed with microencapsulation studies.Double emulsion/evaporation microencapsulation technique was applied to produce polycaprolactonebased microspheres containing H. stoechas hydroalcoholic extract, which were then successfully incor-porated into a moisturizer. The results obtained demonstrated the antioxidant potential of H. stoechashydroalcoholic extract and the viability of its microencapsulation, thus opening new perspectives for theexploitation of these natural phenolic extracts in applications such as the cosmetic industry.
- Extratos fenólicos de Helichrysum stoechas (L.) Moench: caracterização química, atividade antioxidante e encapsulação para utilização em dermocosméticaPublication . Barroso, Marisa; Ferreira, Isabel C.F.R.; Barreiro, M.F.; Carvalho, Ana MariaO presente trabalho teve como objetivo explorar o potencial antioxidante dos compostos fenólicos das sumidades floridas (capítulos e brácteas e os 15 cm terminais dos caules com folhas que suportam as inflorescências) de Helichrysum stoechas (L.) Moench para aplicações cosméticas e envolveu as seguintes etapas: caracterização química, microencapsulação e incorporação num hidratante. As propriedades antioxidantes do extrato hidroalcoólico e da decocção foram avaliadas por métodos químicos (determinação do poder redutor e da capacidade captadora de radicais 2,2-difenil-1-picril-hidrazilo (DPPH) e bioquímicos (inibição da descoloração do β-caroteno na presença de radicais livres derivados do ácido linoleico e inibição da formação de espécies reativas do ácido tiobarbitúrico (TBARS) em homogeneizados cerebrais). A composição fenólica foi analisada por cromatografia líquida de alta eficiência de fase reversa acoplada a deteção de díodos e espetrometria de massa com ionização por spray de eletrões (HPLC-DAD-ESI/MS). Foram identificados dezoito compostos fenólicos diferentes, sendo o ácido 3,5-O-dicafeoilquínico e a miricetina 7-O-acetil-hexósido o ácido fenólico e o flavonoide mais abundante, respetivamente. Comparativamente à decocção, o extrato hidroalcoólico apresentou maior atividade antioxidante e conteúdo fenólico, tendo-se optado pela sua forma liofilizada para prosseguir os estudos de microencapsulação. Para a microencapsulação utilizou-se a técnica da dupla emulsão/evaporação de solvente, produzindo-se microesferas de base policaprolactona (PCL) com o respetivo conteúdo (extrato hidroalcoólico de H. stoechas). Estas foram incorporadas com sucesso num creme hidratante. Os resultados obtidos demonstraram o potencial antioxidante do extrato hidroalcoólico de H. stoechas e a viabilidade da sua microencapsulação, abrindo novas possibilidades de exploração e aplicação destes extratos fenólicos naturais, nomeadamente na indústria de cosméticos.
- In vitro culture and aclimation process of Stevia RebaudianaPublication . Barroso, Marisa; Arrobas, Margarida; Rodrigues, M.A.Stevia rebaudiana (Bert.) Bertoni (Asteraceae) leaves are a natural source of steviol glycosides, which can be used for sweetening and flavouring foods and beverages. The recent interest of farmers on this crop has increased the demand for propagation material. The farmers can use seedlings, cuttings or, alternatively, wealthy plants obtained from in vitro propagation (Madan et al., 2010). This work reports the results of a simple, fast and non-expensive method developed for micro-propagation, rooting and acclimation of Stevia . Objectives: development of a method to micro-propagate, rooting and acclimate Stevia. Methodology: plant material was collected from a commercial clone growing in field. Plant material was sterilized by stirring for 7 minutes in a solution of chlorine 5% plus 10 drops of tween 80 per 100 ml of chlorine solution . Thereafter, the explants were washed in sterilized water and moved to a solution of ethanol 70%, kept there for 5 minutes, washed again and inoculated in two different culture media (medium A- MS without hormones and 20 g/L of sucrose; and medium 8- MS with 0.5 mg/L of kinetin and 20 g/L of sucrose). The multiplication rate was determined for each subculture of 2 months in the two media tested. As complementary data, the fresh weights of 10% of the micro-propagated plants per subculture were determined. The rate of spontaneous rooting was also determined, and trials of plant rooting performed through auxin shocks using 2mg/ ml of IBA (lndole-3-butyric acid)(Abdullateef and Osman,2012), a solution to dip the basal part of 100 Stevia plants for 30 seconds. Thereafter, the plants were transferred to the MS media without hormones but containing activated coal. The time that the plants take to get a minimum of roots allowing them to acclimate to the soil substrate was recorded. The acclimatization in soil substrate was performed in a greenhouse under a misting irrigation system working for 1 0 seconds each 20 minutes. The acclimatization rate was determined during two weeks . Results: In culture media A and 8 the monthly multiplication rates were 383.2 and 306.9%, respectively. The mean plant fresh weights per subculture were 1.1 and 0.9 g, respectively for A and 8 subculture media. In medium A, the rate of spontaneous rooting, after 4 months in culture, was 1 0.5%, and in 8 medium was less than 4%. Rooting induced process was evaluated each week after hormone shock. In the first week, 30% of plants developed roots, having increased this number to 70% in the second week. No significant differences were found in rooting of plants coming from the different initial media growth. The acclimatization rate was 100% after 2 weeks in the greenhouse. Conclusion: Using the medium A (the best suited for multiplication and spontaneous rooting) it was possible to obtain more than 50 times the initial number of plants in excellent developing conditions to be transferred to the field.
- Phenolic profile of Helichrysum stoechas L. MoenchPublication . Barroso, Marisa; Barros, Lillian; Dueñas, Montserrat; Carvalho, Ana Maria; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.Natural matrices represent a rich source of biologically active compounds and are an example of molecular diversity, with recognized potential in drug discovery and development. Many plants frequently used in folk medicine have antioxidant and pharmacological properties connected with the presence of phenolic compounds, especially flavonoids [1]. The biological, pharmacological and medicinal properties of this group of compounds have been extensively reviewed (2]. Ethnobotanical surveys conducted in the Northeast of Portugal highlighted the decoction of Helichrysum stoechas (L.) Moench (shrubby everl asting; port. douradinha) for cold, bronchitis and fever [3]. In the present study, the phenolic composition of H. stoechas (inflorescences and leafy flowering stems) was analyzed by reversed-phase high performance liquid chromatography coupled to diode array detection and mass spectrometry with electron spray ionization (HPLC-DAD-ESI/MS), after extraction with methanol:water (80:20 v/v). Seventeen different phenolic compounds were identified, in which eight were characterized as phenolic acids, being 5-0-caffeoylquinic and 3,5-0-dicaffeoylquinic acids the most abundant compounds. Furthermore, nine flavonols were also identified, mostly derivatives of quercetin and myricetin, being myricetin 0 -acylhexoside the most abundant flavonoid. Overall, the analytical screening by HPLC-MS represents a valid and rapid approach in the search of new bioactive phenolic compounds.
- Potencial antioxidante de Stevia rebaudiana Bertoni cultivada em Portugal e conservada em diferentes condições térmicasPublication . Barroso, Marisa; Barros, Lillian; Prieto Lage, Miguel A.; Sousa, Maria João; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.A procura de adoçantes naturais tem vindo a ganhar cada vez mais importância devido à grande controvérsia associada à utilização de alguns adoçantes artificiais nomeadamente, ciclamatos, aspartame e acesulfame-K. Os glucósidos de esteviol (E 960) constituem um grupo de adoçantes naturais de utilização generalizada, sendo obtidos a partir de Stevia rebaudiana Bertoni, uma planta nativa da América do Sul [1]. No entanto, a referida planta contém outros potenciais de utilização que devem ser explorados, nomeadamente associados à sua capacidade antioxidante. Esta planta já é produzida em Portugal, no entanto, são necessários estudos que comprovem que a sua composição química se mantém independentemente das condições de cultivo. Neste trabalho, utilizaram-se amostras de Stevia cultivadas em Bragança num ensaio de campo com condições de cultivo definidas e, que após colheita, foram submetidas a dois tratamentos de conservação diferentes: em fresco (-20ºC) e desidratadas (30ºC). Foi avaliada a sua atividade antioxidante (efeito captador de radicais livres e poder redutor), tendo sido também determinados alguns compostos bioativos tais como fenóis e flavonoides totais (métodos espetrofotométricos), tocoferóis (HPLC-fluorescência) e açúcares livres (HPLC-RI). Foram observadas diferenças significativas entre as diferentes amostras. A desidratação parece favorecer a atividade antioxidante e a concentração em fenóis e flavonoides. Já as amostras conservadas em fresco apresentaram maiores concentrações de tocoferóis (incluindo isoformas , e ) e açúcares livres, tendo-se identificado e quantificado oito moléculas distintas: ramnose, xilose, arabinose, frutose, glucose, sacarose, trealose e rafinose. Os resultados confirmam que as plantas cultivadas em Bragança possuem metabolitos secundários bioativos responsáveis pela capacidade antioxidante.