Browsing by Author "Silva, Carina Isabel da"
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- Avaliação da atividade antimicrobiana de méis e água-melPublication . Silva, Carina Isabel da; Miguel, Maria Graça; Faleiro, LeonorO mel é conhecido desde a antiguidade não só pelas suas propriedades nutricionais, mas também pelas sua propriedades medicinais. A emergência de estirpes resistentes aos antibióticos tem levado à exploração de agentes alternativos. A utilização do mel no controlo de infeções sob esta ótica está presentemente sob intensa investigação. A capacidade antibacteriana de três tipos de méis monoflorais e duas amostras de água-mel da região do Algarve foi determinada pelo método de microdiluição. O crescimento das estirpes de Staphylococcus aureus resistentes e não resistentes à meticilina e das bactérias Pseudomonas aeruginosa e Mycobacterium bovis foi inibido a concentrações de 25 % e a 50% (p/v). Os méis e as amostras de água-mel testados também inibiram a aderência das bactérias S. aureus e P. aeruginosa em cerca de 31,33% ± 3,08 - 81,04% ± 1,23 e 32,51 ± 0,21 - 73,20% ± 0,52%, respetivamente. O impacto dos méis na virulência das estirpes de S. aureus e P. aeruginosa foi avaliada recorrendo ao modelo Galleria mellonella. A sobrevivência das larvas injetadas com as células de S. aureus tratadas com os meis foi afetada. Não se registram diferenças significativas na sobrevivência das larvas injetadas com as células de P. aeruginosa após tratamento com os méis. Neste estudo foi também avaliada a atividade anti-inflamatória dos méis e água-mel mediante avaliação da atividade enzimática da hialuronidase e lipoxigenase. As percentagens de inibição variaram entre 5,42% ± 0,22 - 94,33% ± 5,67 para a hialuronidase e 55,59% ± 0,24 - 96,57% ± 0,77 para a lipoxigenase. Os méis e as amostras de água-mel analisados apresentaram propriedades anti-inflamatórias, inibiram o crescimento bacteriano e a sua capacidade de aderência, bem como a virulência de estirpes resistentes. Estes produtos com impacto económico na região do Algarve tem um valor acrescido pelas suas propriedades antibacterianas e anti-inflamatórias.
- Effect of essential oils on the release of TNF-α and CCL2 by LPS-Stimulated THP‑1 CellsPublication . Miguel, Maria Graca; Silva, Carina Isabel da; Farah, Luana; Castro Braga, Fernão; Figueiredo, Ana CristinaPlants and their constituents have been used to treat diverse ailments since time immemorial. Many plants are used in diverse external and internal formulations (infusions, alcoholic extracts, essential oils (EOs), etc.) in the treatment of inflammation-associated diseases, such as those affecting the respiratory tract or causing gastrointestinal or joint problems, among others. To support the traditional uses of plant extracts, EOs have been assessed for their alleged anti-inflammatory properties. However, the effect of EOs on the release of cytokines and chemokines has been much less reported. Considering their traditional use and commercial relevance in Portugal and Angola, this study evaluated the effect of EOs on the in vitro inhibition of the cytokine tumor necrosis factor-α (TNF-α) and the chemokine (C-C motif) ligand 2 (CCL2) by lipopolysaccharide (LPS)-stimulated human acute monocytic leukemia cells (THP-1 cells). Twenty EOs extracted from eighteen species from seven families, namely from Amaranthaceae (Dysphania ambrosioides), Apiaceae (Foeniculum vulgare), Asteraceae (Brachylaena huillensis, Solidago virgaurea), Euphorbiaceae (Spirostachys africana), Lamiaceae (Lavandula luisieri, Mentha cervina, Origanum majorana, Satureja montana, Thymbra capitata, Thymus mastichina, Thymus vulgaris, Thymus zygis subsp. zygis), Myrtaceae (Eucalyptus globulus subsp. maidenii, Eucalyptus radiata, Eucalyptus viminalis) and Pinaceae (Pinus pinaster) were assayed for the release of CCL2 and TNF-α by LPS-stimulated THP-1 cells. B. huillensis, S. africana, S. montana, Th. mastichina and Th. vulgaris EOs showed toxicity to THP-1 cells, at the lowest concentration tested (10 μg/mL), using the tetrazolium dye assay. The most active EOs in reducing TNF-α release by LPS-stimulated THP-1 cells were those of T. capitata (51% inhibition at 20 μg/mL) and L. luisieri (15-23% inhibition at 30 μg/mL and 78-83% inhibition at 90 μg/mL). L. luisieri EO induced a concentration-dependent inhibition of CCL2 release by LPS‑stimulated THP-1 cells (23%, 54% and 82% inhibition at 10, 30 and 90 μg/mL, respectively). These EOs are potentially useful in the management of inflammatory diseases mediated by CCL2 and TNF‑α, such as atherosclerosis and arthritis.
- The antibacterial, anti-biofilm, anti-inflammatory and virulence inhibition properties of Portuguese honeysPublication . Silva, Carina Isabel da; S, Azza; Faleiro, Maria Leonor; Miguel, Maria; Neto, LuísIn Portugal, beekeeping activity has a significant weight among livestock production. The antimicrobial activities of Portuguese honeys have been reported, but the anti-biofilm formation and anti-virulence abilities have not been investigated. The main goal of this work was to study the impact of three monofloral honeys (citrus, lavender and strawberry tree) honeys on adherence of Staphylococcus aureus, methicillin-resistant S. aureus (MRSA) and Pseudomonas aeruginosa, as well as the influence of the same honeys on virulence using Galleria mellonella as a model. In addition, the general physico-chemical characterization of these honeys and the microbial quality were also performed. The anti-inflammatory activity was also estimated by analyzing the activity of the enzymes hyaluronidase and lipoxygenase. The tested honeys complied with European legislation and no microbial contamination was observed. Of all the honeys at 12.5 and 25%, w/v the citrus honey caused the highest inhibitory activity against P. aeruginosa. Strawberry tree honey at 25% w/v was able to significantly inhibit the MRSA strains. Anti-biofilm formation and anti-inflammatory activities were observed. The different honeys impaired the virulence of S. aureus and MRSA strains. The Portuguese honeys were capable of combating the tested bacterial pathogens not only by inhibiting their growth but also by affecting important pathogenicity properties, such as adherence and virulence.