Percorrer por autor "Capita, Rosa"
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- Comparative insight upon chitosan solution and chitosan nanoparticles application on the phenolic content, antioxidant and antimicrobial activities of individual grape components of Sousão varietyPublication . Silva, Vanessa; Singh, Rupesh Kumar; Gomes, Nelson; Soares, Bruno Gonçalves; Silva, Adriana; Falco, Virgílio; Capita, Rosa; Alonso-Calleja, Carlos; Pereira, José Eduardo; Amaral, Joana S.; Igrejas, Gilberto; Poeta, PatríciaChitosan, a natural polysaccharide, has been previously proposed as an elicitor in plants to prevent pathogen infections. The present study aimed to analyze the e ect of chitosan solution and chitosan nanoparticles treatment applied on the grapevine variety Sousão with respect to the phenolic composition, antioxidant potential and antibacterial activity of its individual grape components. Grapevine plants of selected lines were sprayed with chitosan solution and chitosan nanoparticles, and ethanolic extracts of stems, seeds and skins were prepared from grapevines treated and not treated with chitosan. Total phenolic, anthocyanin and tannin contents were studied, and the identification of the individual phenolic compounds was performed by HPLC-DAD. The antimicrobial susceptibility method was performed using the Kirby-Bauer disc di usion method against multidrug-resistant bacteria. Overall, there was small increase in the concentration of phenolic compounds, antioxidant and antimicrobial activities in grape components treated with chitosan solution. Seed extracts showed the highest antioxidant and antimicrobial activities. The studied individual components obtained from chitosan-treated grapevines could represent an added value due to the increased antioxidant and antibacterial potentials. The phenolic compounds found in components may be used in food and pharmaceutical industries as natural food preservers and antibiotic adjuvants.
- Evaluation of the phenolic profile of Castanea sativa mill. By-products and their antioxidant and antimicrobial activity against multiresistant bacteriaPublication . Silva, Vanessa; Falco, Virgílio; Dias, Maria Inês; Barros, Lillian; Silva, Adriana; Capita, Rosa; Alonso-Calleja, Carlos; Amaral, Joana S.; Igrejas, Gilberto; Ferreira, Isabel C.F.R.; Poeta, PatríciaThe chestnut industry generates a large amount of by-products. These agro-industrial wastes have been described as potential sources of phenolic compounds with high bioactive potential. Therefore, we aimed to extract the phenolic compounds from chestnut by-products and assess their antioxidant potential and evaluate their antimicrobial activity against multidrug resistant bacteria. The individual phenolic compounds in the ethanolic extracts of chestnut shell, inner shell, bur, and leaves were characterized by HPLC-DAD/electrospray ionization (ESI)-MS. The antioxidant properties were determined by DPPH and ABTS assays. The minimum inhibitory concentration (MIC) and the antimicrobial susceptibility was performed using the Kirby–Bauer disc di usion method against 10 bacterial strains. The major phenolic compounds identified in the extracts were trigalloyl-HHDP-glucose, gallic acid, quercetin, and myricetin glycoside derivatives. All chestnut by-products presented promising antioxidant activity in both assays, with leaf samples the ones presenting the highest antioxidant capacity. The inner shell’s extract was e ective against all Gram-positive and two Gram-negative bacteria; nevertheless, all extracts showed antibacterial activity. Staphylococcus epidermidis showed susceptibility to all extracts while none of the extracts was able to suppress the growth of Escherichia coli and Salmonella enteritidis. Chestnut by-products are a source of phenolic compounds with prominent antioxidant and antimicrobial activities. Nevertheless, further studies should be conducted to assess the correlation between phenolic compounds and the bioactivities obtained.
- High efficacy of ozonated oils on the removal of biofilms produced by methicillin-resistant staphylococcus aureus (MRSA) from infected diabetic foot ulcersPublication . Silva, Vanessa; Peirone, Cecília; Amaral, Joana S.; Capita, Rosa; Alonso-Calleja, Carlos; Marques-Magallanes, José A.; Martins, Ângela; Carvalho, Águeda; Maltez, Luís; Pereira, José Eduardo; Capelo, José Luís; Igrejas, Gilberto; Poeta, Patrícia© 2020 by the authors. Ozone has a high wound healing capacity and antibacterial properties and can be used as a complementary treatment in infections. Methicillin-resistant S. aureus (MRSA) is the most common pathogen found in infected diabetic foot ulcers. Most of MRSA are resistant to several classes of antibiotics and, therefore, there is a need for new, effective, and well-tolerated agents. Thus, we aimed evaluate the antimicrobial and antibiofilm potentials of ozonated vegetable oils against MRSA strains isolated from diabetic foot ulcers. Six ozonated oils were produced with concentrations of ozone ranging from 0.53 to 17 mg of ozone/g of oil. The peroxide values were determined for each oil. Ozonated oils content on fatty acid was determined by gas chromatography equipped with a flame ionization detector. The antimicrobial susceptibility testing was performed by the Kirby-Bauer disk diffusion method and the effect of ozonated oils on biofilm formation ability and on established biofilms was investigated. In general, the content in identified unsaturated fatty acid in oils decreased with the increase of ozonation time and, consequently, the peroxide value increased. Most bacterial strains were inhibited by ozonated oil at a concentration of 4.24 mg/g. Ozonated oils had moderate to high ability to remove adhered cells and showed a high capacity to eradicate 24 h old biofilms. Our results show promising use of ozonated oils on the treatment of infections, in particular those caused by multidrug-resistant MRSA strains.
- Moulds and Mycotoxins in the Meat Production Chain from Slaughterhouse to Market: A Scoping Review on Aspergillus and Penicillium IsolationPublication . Rodrigues, Melissa Alves; Freitas, Lais; Estevinho, Letícia M.; Oliveira, Claudemar; Capita, Rosa; Esteves, AlexandraFungal contamination of meat and meat products represents a significant concern for food safety, particularly due to the potential presence of mycotoxin-producing moulds. This scoping review aimed to map the occurrence and distribution of Aspergillus and Penicillium species along the meat production chain, from slaughterhouse environments to retail products, and to identify associated mycotoxins when reported. A systematic literature search was conducted in the PubMed database, complemented by a search in Google Scholar in accordance with Preferred Reporting Items for Systematic Reviews for Scoping Reviews (PRISMA-ScR) guidelines. Eligible studies reported the isolation of Aspergillus and/or Penicillium species from meat, meat products, or meat-processing environments under natural contamination conditions. The results indicate that both genera are frequently detected throughout the production chain, particularly at processing and storage stages, with several studies reporting species known for mycotoxin production. In addition, the presence of these moulds in processing environments highlights potential implications for both food safety and occupational exposure. However, information on mould occurrence in meat, edible offal, meat products and meat processing environments remains scarce, fragmented and heterogeneous. Overall, this review highlights existing knowledge gaps and underscores the need for harmonised monitoring strategies and further research addressing fungal contamination and mycotoxin risks along the meat production chain.