Browsing by Author "Duarte, J."
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- Acetylcholinesterase Inhibition Activity of Portuguese Thymus Species Essential OilsPublication . Dandlen, S. A.; Miguel, Maria Graça; Duarte, J.; Faleiro, Leonor; Sousa, M. J.; Lima, A. S.; Figueiredo, A. C.; Barroso, J. G.; Pedro, L. G.Thymus species are commonly known in Portugal as thyme and they are currently used as culinary herbs, as well as for ornamental, aromatizing and traditional medicinal purposes. The essential oils isolated from the Portuguese Thymus caespititius (Sect. Micantes), T. camphoratus and T. capitellatus (Sect. Thymus, Subsect. Thymastra), T. carnosus, T. zygis subsp. sylvestris and T. zygis subsp. zygis (Sect. Thymus, Subsect. Thymus) were evaluated for acetylcholinesterase inhibition capacity. A great variability in activity was detected in the assayed essential oils, even among oils isolated from a same species with different geographical origins, such as T. caespititius. T. zygis subsp. zygis essential oil showed the strongest acetylcholinesterase inhibition capacity with an IC50 = 1.1 mu g/ml.
- Antioxidant Capacity of the Essential Oils From Lavandula luisieri, L. stoechas subsp lusitanica, L. stoechas subsp lusitanica x L. luisieri and L. viridis Grown in Algarve (Portugal)Publication . Matos, F.; Miguel, Maria Graça; Duarte, J.; Venancio, F.; Moiteiro, C.; Correia, A. I. D.; Figueiredo, A. C.; Barroso, J. G.; Pedro, L. G.The antioxidant capacity of the essential oils isolated from the aerial parts of Lavandula luisieri, L. stoechas subsp. lusitanica, the hybrid L. stoechas subsp. lusitanica x L. luisieri, and L. viridis collected in different regions of Algarve (Portugal), its well as that of butylated hydroxytoluene (BHT), was evaluated using three different methods: free radical scavenging activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, thiobarbituric acid reactive substances assay (TBARS) and reductive potential. The chemical composition of the essential oils wits analyzed by GC and GC/MS. The oils of L. luisieri were mainly constituted by 1,8-cineole (26-34%) and trans-alpha-necrodyl acetate (11-18%), only present in this lavender species. The oils of Lavandula stoechas subsp. lusitanica and the hybrid L. stoechas subsp. lusitanica x L. luisieri were dominated by fenchone (42-44%) and camphor (35-36%). Despite of the morphological resemblances of the L. stoechas subsp. lusitanica x L. luisieri with L. luisieri, no necrodane derivatives were detected ill the hybrid, showing instead a major chemical similarity with L. stoechas oil. Lavandula viridis oil mainly comprised 1,8-cineole (33%) and camphor (20%). The oils of L. luisieri were the most effective as antioxidants, independent of the evaluation method used, although showing always lower antioxidant ability than BHT.
- Effect of the volatile constituents isolated from Thymus albicans, Th. mastichina, Th. carnosus and Thymbra capitata in sunflower oilPublication . Miguel, Maria Graça; Figueiredo, A. C.; Costa, M. M.; Martins, D.; Duarte, J.; Barroso, J. G.; Pedro, L. G.The composition of essential oils isolated from Thymus albicans and Thymbra capitata collected in Algarve (Portugal), Th. mastichina collected in Algarve and Estremadura (Portugal) and Th. carnosus also collected in Algarve, during the flowering phase, was analysed by gas chromatography (GC) and GC coupled to mass spectrometry (GC-MS). The antioxidant capacity of the oils as well as some of their main components was determined by periodic evaluation of the peroxide values in sunflower oils stored at 60 degreesC. These peroxide values were compared to that of butylated hydroxytoluene (BHT) and control (without adding antioxidants) under the same experimental conditions. The oils of Th. albicans and Th. mastichina, collected in Algarve, were dominated by 1,8-cineole (68% and 45%, respectively), whereas linalool (52%) was the main component from the oils isolated from Th. mastichina collected in Estremadura. Carvacrol (68%) was the major component present in the oils of Thymbra capitata while borneol (18%), terpinen-4-ol (11%) and camphene (9%) were the major ones in the essential oil of Th. carnosus. The essential oils as well as some of their main components showed higher antioxidant capacity than that of the synthetic antioxidant BHT. At the end of the experiment (57 days), BHT showed a percentage of inhibition of 20%, while that of the essential oils ranged from 46% for Th. carnosus, to 59% for Th. mastichina collected in Estremadura.
- O Freixo Duarte de Armas: a história e recuperação da árvorePublication . Martins, L. M.; Silva, C. A.; Sousa, H.; Mariano, Alexandra de Brito; Madeira, S.; Sintra, A.P.; Leal, F.; Ferreira-Cardoso, J.; Duarte, J.; Rodrigues, A.; Quintas, M. C.
- O Freixo Duarte de Armas: a história e recuperação da árvorePublication . Martins, L. M.; Silva, C. A.; Sousa, H.; Mariano, Alexandra de Brito; Madeira, S.; Sintra, A. P.; Leal, F.; Ferreira-Cardoso, J.; Duarte, J.; Pinto, T.; Quintas, M. C.O Freixo (Fraxinus angustifolia Vahl.) com mais de 550 a que se refere esta comunicação, localiza-se na área histórica de Freixo de Espada à Cinta (FEC). A árvore e FEC confundem-se devido ao nome e à longevidade de ambos, embora a localidade seja bem mais velha, sendo até mais antiga que a fundação de Portugal independente. Na verdade, a história do agora chamado Freixo Duarte de Armas (Fd’A) só se inicia com o seu registo em 1510 no Livro das Fortalezas, por Duarte de Armas (Dd’A). O escudeiro do rei D. Manuel I representou junto à muralha, o freixo que viveu até aos nossos dias
- Honey-based “Agua-mel” chemical haracterization and microbiological qualityPublication . Miguel, Maria Graça; Antunes, Maria Dulce; S, Azza; Duarte, J.; Faleiro, LeonorIn Mediterranean countries such as Italy and Portugal an ancient practice among beekepers is the production of a honey-based product that is called "agua-mel" (Portuguese designation) or "abbamele" (Italian designation) that have not only food applications but also medicinal purposes. However, the characterization of such foodstuff is completely absent in Portugal. In our study the main goal was to provide the general chemical characterization and the microbiological quality of samples of "agua-mel". The chemical characterization showed a great variability of the ash percentage (0.167-0.474); electrical conductivity (407-1067 mu S/cm); free acidity (33.2-91.2 meq/kg); lactone acidity (14.60-20.50 meq/kg); total acidity (53.7-122.72 meq/kg); glucose (185.57-258.52 g/kg); fructose (218.49-315.36 g/kg); total polyphenols (1780.0-4963.8 mg/kg); flavonoids (188.8-1702.4 mg/kg) and 5-(hydroxymethyl)-2-furaldehyde (HMF) (1812.6-8428.9 mg/kg), depending on the beekeeper and production year. The microbiological quality included the counts of aerobic mesophilic bacteria, yeasts and moulds, Enterobacteriaceae, sulphite-reducing Clostridium spp. and the presence of Salmonella spp. The results showed that from all "agua-mel" samples analyzed only one sample was contaminated with Clostridium spp. and aerobic mesophilic bacteria. Taken together both chemical and microbiological data indicates a safe consumption of "agua-mel".
- Propolis volatiles characterisation from acaricide-treated and -untreated beehives maintained at Algarve (Portugal)Publication . Miguel, Maria Graça; Nunes, S.; Cruz, C.; Duarte, J.; Antunes, Maria Dulce; Cavaco, A. M.; Mendes, M. D.; Lima, A. S.; Pedro, L. G.; Barroso, J. G.; Figueiredo, A. C.The variability of the volatile profile of 70 propolis samples from acaricide-treated and -untreated beehives maintained at Algarve (Portugal) was evaluated. Propolis samples were collected in three regions of Algarve at three different periods. Cluster analysis based on the propolis volatiles' chemical composition defined two main clusters, not related to the time of year, collection site, altitude, temperature or humidity ranges, and was based mainly on the relative amounts of viridiflorol, n-tricosane and n-nonadecane for cluster I. Cluster II was mainly characterised by the high thymol content, followed by viridiflorol, n-tricosane and n-nonadecane. The presence of higher thymol levels in propolis samples from cluster II may reflect the long use of an acaricide with thymol as main active ingredient. All samples showed an intense rock-rose aroma supported by the presence of characteristic Cistus and labdanum oil volatile components. Given the nowadays frequent propolis household use, volatiles thorough characterisation may assist in its quality assessment.
- Trichoderma gamsii as a biological control agent of turfgrass diseasesPublication . Coelho, Luísa; Dionísio, Lídia; Bueno-Pallero, Francisco; Reis, Mário; Duarte, J.; Guerrero, CarlosGolf is a growing and economically important activity in Portugal with direct and indirect incomes respectively over 350 and 1.450 million of euros, corresponding nearly 1.25% of the Gross National Product. The correct maintenance of lawns in a sustainable manner is required. Sport lawns are quite susceptible to soil-borne diseases1 , which cause enormous economic losses, making environmental friendly disease control methods a practice to develop. The increasing interest regarding environment and public health protection have been increased the search for alternatives, leading researchers to seek strategies to reduce the use of synthetic products, such as fertilizers and pesticides2 . Also, the European legislation is directing the reduction of pesticides3 , facing itself towards more sustainable policies.