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Percorrer por autor "Madureira, A. R."

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  • Chitosan in oral health: a proof of concept
    Publication . Costa, E. M.; Silva, Sara; Cardelle-Cobas, A.; Madureira, A. R.; Ferreira, M. O.; Tavaria, Freni K.; Pintado, M. M.
    Nowadays chitosan has established itself as a high sought material due to its biocompatibility, reduced toxicity and highpercentage of amino groups that confer it specific functionalities, including antimicrobial activity and acceleration of woundhealing, and studies into chitosan’s applicability have shown chitosan’s potential and feasibility. One of the possible fieldsof application for chitosan based products is the oral cavity, since several of the existing oral health products possesssecondary effects. The aim of this work was to prove that chitosan is a feasible component for oral health productsbiofabrication. As such a chitosan based mouthwash was developed and validated through assessment ofin vitroandin vivoantimicrobial activity, antibiofilm activity and sensory properties. The results obtained showed that it was possible tosuccessfully incorporate chitosan in an oral care product while retaining a considerable antimicrobial activity.In vitrotestingdemonstrated that the chitosan mouthwash possessed a wide range of antimicrobial activity against oral pathogens andwas capable of inhibiting microbial adherence and biofilm formation. Direct comparison with two commercial mouthwashesshowed that the chitosan mouthwash possessed stronger activity than both reference samples.In vivotesting showedthat the chitosan mouthwash was very effective in reducing enterococci and streptococci bacterial counts up to 30 min.after rinsing. Overall, the present shows a successful development of a chitosan-based product and is a tangible proof ofconcept for future utilization of chitosan in oral health.
    2013Artigo científico Acesso restrito Ver mais
  • Chitosan mouthwash: toxicity and in vivo validation
    Publication . Costa, E. M.; Silva, S.; Costa, M. R.; Pereira, M.; Campos, D. A.; Odila, J.; Madureira, A. R.; Cardelle-Cobas, A.; Tavaria, F. K.; Rodrigues, A. S.; Pintado, M. M.
    A previous study showed that a chitosan mouthwash would be a valid alternative to current mouthwashesas it demonstrated, in vitro, significantly higher antibiofilm activity than two commercial mouthwashes.As such, the aim of this work was to verify the safety of the developed product and to validate, in vivo, thebiological activity ascertained in vitro. Chitosan mouthwash safety was evaluated through Ames, MTT andV79 chromosomal aberration assay while antimicrobial activity was evaluated through in vivo assays. Theresults showed that the chitosan mouthwash was safe, presenting lower cytotoxicity than a commercialmouthwash, and that it effectively reduced viable counts of Streptococcus spp. and Enterococcus spp. by ca.5.5 log of CFU. Furthermore, in direct comparison with a commercial mouthwash the chitosan mouthwashpossessed significantly higher antimicrobial activity. The conjunction of these results proves that thechitosan mouthwash is a safe, effective, natural alternative to the existent chemical mouthwashes.
    2014Artigo científico Acesso restrito Ver mais
  • A comprehensive study into the impact of a chitosan mouthwash upon oral microorganism's biofilm formation in vitro
    Publication . Costa, E. M.; Silva, S.; Madureira, A. R.; Cardelle-Cobas, A.; Tavaria, F.K.; Pintado, M. E.
    Modern dentistry emphasizes the importance of dental plaque control to improve oral health. To that endthe development of oral care formulations has been geared toward the incorporation of antiplaque agentsthat may play a crucial role in oral health maintenance. In later years the research into antiplaque agentshas led to the discovery of compounds with significant capability to affect biofilm formation. Among thesecompounds was chitosan, a polysaccharide which showed great ability to interfere with Streptococcusmutans biofilm formation. As such the aim of this work was to incorporate chitosan into a mouthwashmatrix and assess its effect upon biofilm formation of oral microorganisms. This assessment was per-formed via study of the impact the mouthwash upon microbial adherence, biofilm formation and maturebiofilms. Additionally, the action of the chitosan mouthwash was compared with two commerciallyavailable mouthwashes. The results here obtained show that only the chitosan containing mouthwashwas capable of interfering with all microorganisms’ adherence, biofilm formation and mature biofilmswhile at the same time showing vastly superior activity than both commercial mouthwashes assayed.As such a chitosan mouthwash shows great potential as a natural and efficient alternative to traditionalmouthwashes.
    2014Artigo científico Acesso restrito Ver mais
  • Development of oral films containing chitosan
    Publication . Cardelle-Cobas, A.; Madureira, A. R.; Costa, E.; Tavaria, Freni; Pintado, M. E.
    2012Documento de conferência Acesso aberto Ver mais
  • Effect of diets with different non-starch polysaccharides profiles on gilthead seabream (Sparus aurata) growth and appetite regulation
    Publication . Guttuso, P.; Santos, R. A.; Pousão-Ferreira, P.; Carvalho, N. M. de; Madureira, A. R.; Serra, C. R.; Oliva-Teles, A.; Guerreiro, I.
    Plant feedstuffs are the most established alternative to fish meal in the feed industry but although being readily available and economically viable, the presence of non-starch polysaccharides (NSPs) might impair their use. Accounting the NSP profile of plant feedstuffs, a gilthead seabream (Sparus aurata) growth trial was run testing five isolipidic and isoproteic plant feedstuffs-based diets with 30% inclusion levels of soybean rapeseed, sunflower, or a mixture of these ingredients (10% each), and a control diet with none of those ingredients. Growth and nutritional performance were assessed, and intestinal short chain fatty acids (SCFAs) were estimated as an indicator of gut microbiota metabolism. Moreover, appetite- related gene expression was evaluated in the hypothalamus, stomach, liver, and anterior intestine. No mortality was recorded during the study, and no significant differences in growth parameters, feed utilization, body composition, and visceral somatic index were found among dietary treatments. Hepatosomatic index, lipid retention, and liver lipid composition results highlighted the role of dietary carbohydrates in liver lipid deposition, being significantly higher in fish fed the Control diet which possessed the highest starch level. Acetate was the only SCFA detected with significantly higher concentration in the gut content of fish fed the Sunflower and Mix diets than in fish fed the Control and Rapeseed diets. Regarding appetite- related gene expression in hypothalamus, cocaine and amphetamine regulated transcript, neuropeptide Y and agouti-related peptide presented the same expression across treatments. In liver and stomac significant differences were not detected for leptin and ghrelin expression, respectively. In the anterior intestine, despite cholecystokinin relative gene expression did not present significant difference, it underlined a similar trend to peptide YY where Soybean, Sunflower, and Mix diets presented significantly higher relative gene expression than in fish fed Control diet. In conclusion, gilthead seabream presented a good performance when fed the plant feedstuffs- based diets rich in dietary fiber and NSPs. The diverse plant feedstuffs-based mixtures affected specific metabolic pathways, and microbial metabolism potentially affected appetite-related gene expression.
    2023-12-07Documento de conferência Acesso aberto Ver mais
  • Incorporation of probiotic bacteria in whey cheese: decreasing the risk of microbial contamination
    Publication . Madureira, A. R.; Pintado, M.; Gomes, Ana Maria; Malcata, F. Xavier
    For dairy products that are consumed fresh, contamination by spoilage microorganisms and pathogens from the environment is a major concern. Contamination has been associated with a number of outbreaks of foodborne illnesses; however, consistent data pertaining to the microbial safety of whey cheeses specifically have not been reported. Hence, the goals of this research effort were (i) to manufacture a probiotic whey cheese with Bifidobacterium animalis and Lactobacillus casei and (ii) to assess the antimicrobial activity of these probiotics against a set of foodborne pathogens (Listeria innocua, Salmonella Enteritidis, and Staphylococcus aureus) and food spoilage microorganisms (Pseudomonas aeruginosa and Escherichia coli). Three ranges of these microbial contaminants were used for inoculation of cheeses: 103 to 104, 104 to 106, and 106 to108 CFU/g. Inoculation in plain culture medium served as a control. The inhibition produced by the probiotics was calculated, and the major effect was found to be bacteriostatic. In specific cases, full inhibition was observed, i.e., by B. animalis against P. aeruginosa and by L. casei against Salmonella Enteritidis and L. innocua. Conversely, the least inhibition was detected for L. casei against P. aeruginosa. Our results suggest that use of these probiotic strains can extend the shelf life of whey cheeses and make them safer by delaying or preventing growth of common contaminant bacteria.
    2011Artigo científico Acesso restrito Ver mais
  • Invited review: physiological properties of bioactive peptides obtained from whey proteins
    Publication . Madureira, A. R.; Tavares, T.; Gomes, A. M. P.; Pintado, M. E.; Malcata, F. Xavier
    Processing of whey proteins yields several bioactive peptides that can trigger physiological effects in the human body: on the nervous system via their opiate and ileum-contracting activities; on the cardiovascular system via their antithrombotic and antihypertensive activities; on the immune system via their antimicrobial and antiviral activities; and on the nutrition system via their digestibility and hypocholesterolemic effects. The specific physiological effects, as well the mechanisms by which they are achieved and the stabilities of the peptides obtained from various whey fractions during their gastrointestinal route, are specifically discussed in this review.
    2010Artigo científico Acesso restrito Ver mais
  • A novel direct contact method for the assessment of the antimicrobial activity of dental cements
    Publication . Costa, E. M.; Silva, S.; Madureira, A. R.; Cardelle-Cobas, A.; Tavaria, F. K.; Pintado, M. M.
    Dental cements are a crucial part of the odontological treatment, however, due to the hazardous nature and reduced biological efficiency of some of the used materials, newer and safer alternatives are needed, particularly so those possessing higher antimicrobial activity than their traditional counterparts. The evaluation of the antimicrobial properties of solid and semi-solid antimicrobials, such as dental cements and gels, is challenging, particularly due to the low sensitivity of the current methods. Thus, the main aim of this study was the evaluation of the antimicrobial activity of a novel chitosan containing dental cement while simultaneous assessing/validating a new, more efficient, method for the evaluation of the antimicrobial activity of solid and gel like materials. The results obtained showed that the proposed method exhibited a higher sensitivity than the standard 96 well microtiter assay and allowed the determination of bactericidal activity. Additionally, it is interesting to note that the chitosan containing cement, which presented higher antimicrobial activity than the traditional zinc oxide/eugenol mix, was capable of inducing a viable count reduction above 5 log of CFU for all of the studied microorganisms.
    2013Artigo científico Acesso restrito Ver mais
  • Recuperación y revalorización del lactosuero para la producción de nuevos produtos con propriedades funcionales
    Publication . Madureira, A. R.; Pintado, Ana I. E.; Gomes, Ana M. P.; Malcata, F. X.; Pintado, M. E.
    En los últimos años han surgido gran cantidad de alimentos funcionales a los que se les atribuyen diversas propiedades beneficiosas. Entre estos alimentos se encuentran aquellos que contienen proteínas del lactosuero así como aquellos que incorporan bacterias probióticas en su composición. En la actualidad existen matrices de proteínas de suero que contienen bacterias probióticas que se mantienen viables durante 28 días a temperaturas de refrigeración. Además, también se han realizado diferentes estudios relacionados con la actividad metabólica, las propiedades antimicrobianas y la resistencia a las enzimas del tracto gastrointestinal. Por último, se ha evaluado el uso de cepas de bacterias del ácido láctico con propiedades probióticas en la producción de exopolisacáridos en lactosuero.
    2009Capítulo de livro Acesso aberto Ver mais
  • Study of in vitro digestion of Tenebrio molitor flour for evaluation of its impact on the human gut microbiota
    Publication . Carvalho, N. Mota de; Walton, G. E.; Poveda, C. G.; Silva, S. N.; Amorim, M.; Madureira, A. R.; Pintado, M. E.; Gibson, G. R.; Jauregi, P.
    Human diet has evolved to include not only nutritious foods but also health-promoting ones. Moreover, there is an increasing interest in replacing animal proteins as the main protein source. Insect based foods, e.g. Tenebrio molitor insect flour (TMIF), show potential as alternative protein sources for the human diet. This work aims to provide insights into the effect of TMIF upon the human gut microbiota and their metabolic end products by using an in vitro fecal model. Digested TMIF had a positive impact on gut microbiota, observed as an increase and/or upkeep of health promoting bacterial groups and by the production of SCFA (1.7 and 2.6 times higher acetate and propionate produced respectively than in the negative control at 48 h) and BCFA. A path is opened to acknowledge TMIF as a possible healthy nutritional source for human consumption, although in vivo trials would be necessary to confirm this.
    2019Artigo científico Acesso aberto Ver mais