Browsing by Author "Carvalho, Rosa Paula"
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- Avaliação do efeito do coberto vegetal do solo nos compostos fenólicos e na capacidade antioxidante das azeitonas.Publication . Fernandes-Silva, Anabela; Rodrigues, Joseanne Rodella; Carvalho, Rosa Paula; Brito, Cátia; Rodrigues, M.A.; Moutinho-Pereira, José; Correia, Carlos M.Em Portugal, a região de Trás-os-Montes representa o segundo lugar, a nível de importância, quer em termos de área de olival e de produção de azeite. A cultivar Cobrançosa é uma das principais cultivares da região, representando cerca 30% do total, sendo cultivada, principalmente para a produção de azeite. O olival tradicional de sequeiro mantém ainda hoje importância social e económica na região, sendo a olivicultura uma das poucas atividades com capacidade para gerar rendimentos e contribuir para a fixação da população. O estudo foi desenvolvido na região da Terra Quente Transmontana (Suçães, Mirandela; 40,5°N; 7,2°W). O olival foi instalado num compasso de 7 m x7 m em regime de sequeiro. O objetivo do estudo, foi o de avaliar o efeito da gestão da superfície do solo sobre o conteúdo em polifenóis totais, orto-difenóis e capacidade antioxidante das azeitonas da Cv "Cobrançosa". Para o efeito, foram comparados dois sistemas de manutenção da superfície do solo: i) mobilização tradicional (MT), ii) cobertura com leguminosas, ou seja, 10 espécies de trevo de ciclo anual e resementeira natural, (CL). Em cada tratamento foram amostradas três oliveiras, e recolhidos 50 frutos à altura do peito. Posteriormente foi quantificado o conteúdo em polifenóis totais, orto-difenois e atividade antioxidante (método do DPPH). Os resultados são preliminares e reportam-se ao ano de 2011 e são expressos em relação à matéria seca (MS). Verificaram-se diferenças significativas para os três parâmetros analisadas. No que concerne ao conteúdo em polifenois totais, observou-se que no MT foram encontrados os valores superiores (35 620 ± 145 mg GAE kg-1 MS) e no CL os menores (14 703,2 ± 612 mg GAE kg-1 MS) demostrando uma redução para cerca de metade. Os orto-difenóis revelaram também uma tendência de diminuição do MT (2313,4 ± 15,6 mg GAE kg-1 MS) para o CL (1908,6 ± 39,0 mg GAE kg-1 MS) traduzindo-se numa diminuição de 18%. Relativamente à atividade antioxidante, revelou a mesma tendência de comportamento, com uma redução de 28 %do MT (80,0% ±4,6) para o CL (57,6% ± 0,9). A diminuição destes compostos poderá ser atribuída ao menor grau de défice de água no solo no tratamento CL, verificado neste estudo (Fernandes-Silva et al.,2012) e, portanto, a melhor estado hídrico das plantas no CL.
- Effects of soil and foliar application of nitrogen and boro non a.tocoferol and antioxidant properties of two varieties (Glorieta and Masbovera) of almond grown in Northeast of PortugalPublication . Aires, Alfredo; Morais, Cristina; Prgomet, Iva; Oliveira, Ivo; Bernardo, Sara; Afonso, Sílvia Martins; Carvalho, Rosa Paula; Barreales, David; Rodrigues, M.A.; Ribeiro, A.C.; Gonçalves, Berta C.C.; Silva, A.P.The aim of the current study was to determine the effects of two fertilizers, boron and nitrogen, on the nutritional quality of two cultivars od almonds (Prunus Dulcis Mill.) Glorieta and Masbovera grown in Alfandega da Fé region, Northeast of Portugal.
- Phytochemical composition and antioxidant properties of portuguese kale and portuguese tronchuda cabbage produced in a sustainable agriculture production system are affected by climate conditionsPublication . Aires, Alfredo; Carvalho, Rosa Paula; Fernandes, Conceição; Saavedra, Maria José; Rosa, Eduardo
- Phytochemical composition and antioxidant properties of portuguese kale and portuguese tronchuda cabbage produced in a sustainable agriculture production system are affected by climate conditionsPublication . Aires, Alfredo; Carvalho, Rosa Paula; Fernandes, Conceição; Saavedra, Maria José; Rosa, Eduardo
- Platanus hybrida’s phenolic profile, antioxidant power, and antibacterial activity against methicillin-resistant staphylococcus aureus (MRSA)Publication . Ribeiro, Jessica; Silva, Vanessa; Aires, Alfredo; Carvalho, Rosa Paula; Barros, Lillian; Gaivão, Isabel; Igrejas, Gilberto; Poeta, PatríciaMethicillin-resistant S. aureus (MRSA) are a threat to public health as they frequently reveal a multidrug-resistant pattern. Researchers all over the world are on an urgent hunt for new treatments to help fight infections before antibiotics become obsolete, and some natural alternatives, such as polyphenols, have already exhibited therapeutic properties. Therefore, this study aimed to determine the phenolic profile, antioxidant capacity, and antimicrobial activity against MRSA of the leaf, fruit, and stem bark extracts of Platanus hybrida. The polyphenols were extracted with a water/ethanol (20:80) mixture and the methodology included HPLC-DAD, DPPH, FRAP, and CuPRAC. To address this issue from a One Health perspective, the Kirby–Bauer disc diffusion method was performed against nine MRSA strains from three different sources (livestock, wild animals, and humans). Fourteen phenolics were identified and the leaf extract showed the highest phenolic content, followed by the fruit extract. The leaf extract also showed the highest antioxidant capacity while the fruit extract had the lowest antioxidant capacity. Both leaf and fruit extracts inhibited the growth of strains from all sources, while the stem bark extract did not inhibit the growth of human strains. This work highlights the complex chemical composition and the antioxidative and antimicrobial potential of extracts derived from P. hydrida.
- Screening of chemical composition, antimicrobial and antioxidant activities in pomegranate, quince, and persimmon leaf, peel, and seed: valorization of autumn fruits by-products for a one health perspectivePublication . Silva, Vanessa; Silva, Adriana; Ribeiro, Jessica; Aires, Alfredo; Carvalho, Rosa Paula; Amaral, Joana S.; Barros, Lillian; Igrejas, Gilberto; Poeta, PatríciaAntimicrobial resistance is increasing globally and is now one of the major public health problems. Therefore, there is a need to search for new antimicrobial agents. The food industry generates large amounts of by-products that are rich in bioactive compounds, such as phenolic compounds, which are known to have several health benefits, including antioxidant and antimicrobial properties. Thus, we aimed to characterize the phenolic compounds present in pomegranate, quince, and persimmon by-products, as well as their antioxidant and antimicrobial activities. Phenolic compounds were extracted from pomegranate, quince, and persimmon leaves, seeds, and peels using a mixture of ethanol/water (80/20). The polyphenol profile of the extracts was determined by high-performance liquid chromatography. The antioxidant activity of the extracts was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC) methods. Antimicrobial susceptibility was evaluated using the Kirby–Bauer disk diffusion method. In general, leaves showed higher concentrations of phenolics than the peel and seeds of fruits. In total, 23 phenolic compounds were identified and quantified, with sanguiin and apigenin-3-O-galactoside being present in the highest concentrations. Leaf extracts of pomegranate showed higher antioxidant activities than the other components in all methods used. In general, all extracts had a greater antimicrobial activity against Gram-positive bacteria. Persimmon leaf and seed extracts inhibited a greater number of bacteria, both Gram-positive and -negative. The lowest minimum inhibitory concentration (MIC) detected among Gram-positive and -negative bacteria was 10 mg/mL for pomegranate peel and leaf extracts against Staphylococcus aureus and S. pseudintermedius and for pomegranate leaf extract against Escherichia coli. Our results reinforce the need to value food industry by-products that could be used as food preservatives and antibiotic adjuvants against multiresistant bacteria.
- Seasonal effects on bioactive compounds and antioxidant capacity of six economically important brassica vegetablesPublication . Aires, Alfredo; Fernandes, Conceição; Carvalho, Rosa Paula; Bennett, Richard N.; Saavedra, Maria José; Rosa, EduardoResearch on natural and bioactive compounds is increasingly focused on their effects on human health, but there are unexpectedly few studies evaluating the relationship between climate and natural antioxidants. The aim of this study was analyze the biological role of six different Brassica vegetables (Brassica oleracea L. and Brassica rapa L.) as a natural source of antioxidant compounds. The antioxidant activity may be assigned to high levels of L-ascorbic acid, total phenolics and total flavonoids of each sample. The climate seasons affected directly the concentration of bioactive components and the antioxidant activity. Broccoli inflorescences and Portuguese kale showed high antioxidant activity in Spring-Summer whilst turnip leaves did so in Summer-Winter. The Brassica vegetables can provide considerable amounts of bioactive compounds and thus may constitute an important natural source of dietary antioxidants.