Browsing by Author "Pintado, Manuela"
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- Ação antimicrobiana de extratos fenólicos de cogumelos silvestres contra Neisseria gonorrhoeaePublication . Alves, Maria José; Marques, Azucena; Ferreira, Isabel C.F.R.; Martins, Anabela; Pintado, ManuelaO relatório da OMS publicado em 2001 faz referência à estimativa de que mais de seis milhões de casos de gonorreia (infeção causada pela Neisseria gonorrhoeae) ocorrem a cada ano e com índices crescentes, principalmente nos países em desenvolvimento. Por outro lado, tem-se vindo a verificar uma resistência emergente deste microrganismo aos agentes antimicrobianos comuns no seu tratamento, sendo um grande obstáculo no controle de gonorreia [1,2]. Assim, é urgente a descoberta de novas soluções antimicrobianas no combate a esta infeção. O objetivo do presente trabalho foi avaliar a atividade antimicrobiana de extratos e respetivos compostos fenólicos puros de oito espécies de cogumelos silvestres, provenientes do Nordeste de Portugal, contra Neisseria gonorrhoeae obtida de exsudados da uretra no CHTMAD – Centro Hospitalar de Trás-os-Montes e Alto Douro, Portugal. Para a determinação das concentrações mínimas inibitórias (CMI) de crescimento recorreu-se ao método da microdiluição e ao ensaio colorimétrico com cloreto de p-iodonitrotetrazólio (INT). Os resultados demostraram que todos os extratos testados, na gama de concentrações testadas (10,0 – 20,0 mg/mL), conseguiam inibir completamente o crescimento de Neisseria gonorrhoeae. De todos as espécies testadas, os extratos de Agaricus bisporus, Lactarius deliciosus, Russula delica e Sarcodon imbricatus foram aqueles que apresentaram maior atividade em concentrações de extrato muito reduzidas (CMI= 1,25 mg/mL). O extrato de Leucopaxillus giganteus apresentou uma CMI = 2,5 mg/mL e o de Ramaria botrytis e Agaricus arvenses apresentaram uma CMI de 10 mg/mL. O extrato de Tricholoma portentosum demonstrou ser o de menor atividade contra Neisseria gonorrhoeae, com uma CMI elevada (20 mg/mL). Dos principais compostos fenólicos presentes nos extratos, identificados e quantificados por cromatografia líquida de alta eficiência acoplada a deteção de díodos (HPLC-DAD), os ácidos protocatéquico, p-cumárico e cinâmico inibiram a Neisseria gonorrhoeae para uma concentração de 1mg/mL, não se verificando qualquer atividade antimicrobiana para o ácido p-hidroxibenzóico. De um modo geral, todos os extratos apresentaram atividade antimicrobiana sobre a Neisseria gonorrhoeae, sendo pertinente estudar no futuro a sua toxicidade celular no sentido de avaliar possíveis aplicações clínicas na terapêutica e mesmo na prevenção da gonorreia.
- Ação antimicrobiana de extratos fenólicos de cogumelos silvestres contra Neisseria gonorrhoeaePublication . Alves, Maria José; Marques, Azucena; Ferreira, Isabel C.F.R.; Martins, Anabela; Pintado, ManuelaInfeções pelo gonococo e por clamídia estão entre as doenças sexualmente transmissíveis mais comuns causadas por bactérias no mundo. Por outro lado, tem-se verificado um aumento de resistência da Neisseria gonorrhoeae aos diferentes antimicrobianos usados no mercado, sendo desta forma urgente a descoberta de novas soluções antimicrobianas no combate a esta infeção. Assim, o objetivo do presente trabalho foi avaliar a atividade antimicrobiana de extratos e respetivos compostos fenólicos puros de nove espécies de cogumelos silvestres, provenientes do Nordeste de Portugal, contra Neisseria gonorrhoeae obtida de exsudados da uretra no CHTMAD – Centro Hospitalar de Trás-os-Montes e Alto Douro. Para a determinação das concentrações mínimas inibitórias (CMI) de crescimento recorreu-se ao método da microdiluição e ao ensaio colorimétrico com cloreto de p-iodonitrotetrazólio (INT). De um modo geral, todos os extratos apresentaram atividade antimicrobiana sobre a Neisseria gonorrhoeae, e alguns compostos parecem apresentar boa atividade antimicrobiana para esta bactéria, tornando-se pertinente estudar o mecanismo de ação destes compostos na inibição da bactéria bem como a sua toxicidade celular no sentido de avaliar possíveis aplicações clínicas na terapêutica e mesmo na prevenção da gonorreia.
- Alginate Edible Films Containing Essential Oils: Characterization and Bioactive PotentialPublication . Lopes, Ana I.; Melo, Adma; Afonso, Tiago B.; Silva, Sara; Barros, Lillian; Tavaria, Freni K.; Pintado, ManuelaEssential oils (EOs) are natural substances rich in phenolic compounds with notable antimicrobial and antioxidant properties. However, they present some limitations, such as low stability and bioavailability. Incorporating EOs into polymeric films offers a novel approach to overcome these challenges while enhancing their efficacy. In this study, we produced and thoroughly characterized alginate-based edible films incorporated with five different EOs—rosemary, eucalyptus, oregano, sage, and thyme. This is the first comprehensive investigation to include this diverse range of EOs in alginate films. Their antimicrobial and antioxidant activities were also evaluated. The results demonstrated that alginate films containing EOs exhibited significant bioactive properties. Notably, the film incorporated with oregano EO completely inhibited the growth of all tested bacteria and fungi and showed the highest antioxidant activity. Based on these findings, alginate films containing EOs present promising bioactive potential and could serve as biodegradable alternatives to conventional packaging materials, reducing environmental impact. However, further studies are necessary to assess their safety profile and confirm their viability as replacements for traditional food packaging. Future research should focus on evaluating cytotoxicity, genotoxicity, and the practical application of these films in food matrices.
- Antimicrobial activity of phenolic compounds identified in wild mushrooms, SAR analysis and docking studiesPublication . Alves, Maria José; Ferreira, Isabel C.F.R.; Froufe, Hugo J.C.; Abreu, Rui M.V.; Martins, Anabela; Pintado, ManuelaAim and Methods: Although the antimicrobial activity of extracts from several mushroom species have been reported, studies with the individual compounds present in that extracts are scarce. Herein, the antimicrobial activity of different phenolic compounds identified and quantified in mushroom species from all over the world was evaluated. Furthermore, a structure activity relationship (SAR) analysis and molecular docking studies were performed, in order to provide insights in the mechanism of action of potential antimicrobial drugs for resistant microorganisms. Results: 2,4-Dihydroxybenzoic and protocatechuic acids were the phenolic compounds with higher activity against the majority of Gram negative and Gram positive bacteria. Furthermore, phenolic compounds inhibited more MRSA than methicillin sensible Staphylococcus aureus. MRSA was inhibited by 2,4-dihydroxybenzoic, vanillic, syringic (MICs=0.5 mg/mL) and p-coumaric (MIC= 1 mg/mL) acids, while these compounds at the same concentrations had no inhibitory effects against methicillin sensible Staphylococcus aureus. Conclusions: The presence of carboxylic acid (COOH), two hydroxyl (OH) groups in para and ortho positions of the benzene ring, as also a methoxyl (OCH3) group in the meta position seems to be important for anti-MRSA activity. Significance and Impact of the Study: Phenolic compounds could be used as antimicrobial agents, namely against some microorganisms resistant to commercial antibiotics.
- Antimicrobial activity of wild mushrooms extracts against clinical isolates resistant to different antibioticsPublication . Alves, Maria José; Ferreira, Isabel C.F.R.; Martins, Anabela; Pintado, ManuelaAims: This work aimed to screen the antimicrobial activity of aqueous methanolic extracts of 13 mushroom species, collected in Braganc¸a, against several clinical isolates obtained in Hospital Center of Tra´s-os-Montes and Alto Douro, Portugal. Methods and Results: Microdilution method was used to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). MIC results showed that Russula delica and Fistulina hepatica extracts inhibited the growth of gram-negative (Escherichia coli, Morganella morganni and Pasteurella multocida) and gram-positive (Staphylococcus aureus, MRSA, Enterococcus faecalis, Listeria monocytogenes, Streptococcus agalactiae and Streptococcus pyogenes) bacteria. A bactericide effect of both extracts was observed in Past. multocida, Strep. agalactiae and Strep. pyogenes with MBC of 20, 10 and 5 mg ml 1, respectively. Lepista nuda extract exhibited a bactericide effect upon Past. multocida at 5 mg ml 1 and inhibited Proteus mirabilis at 20 mg ml 1. Ramaria botrytis extract showed activity against Enterococcus faecalis and L. monocytogenes, being bactericide for Past. multocida, Strep. agalactiae (MBCs 20 mg ml 1) and Strep. pyogenes (MBC 10 mg ml 1). Leucopaxillus giganteus extract inhibited the growth of E. coli and Pr. mirabilis, being bactericide for Past. multocida, Strep. pyogenes and Strep. agalactiae. Conclusions: Fistulina hepatica, R. botrytis and R. delica are the most promising species as antimicrobial agents. Significance and Impact of the Study: Mushroom extracts could be an alternative as antimicrobials against pathogenic micro-organisms resistant to conventional treatments.
- Application of encapsulated tomato by-product extract as a colorant in mascarponePublication . Molina, Adriana K.; Leichtweis, Maria Gabriela; Machado, Manuela; Silva, Sara; Pintado, Manuela; Barreira, João C.M.; Dias, Maria Inês; Prieto Lage, Miguel A.; Barros, Lillian; Pereira, CarlaAgricultural by-products, often underutilized, represent a significant opportunity to obtain sustainable value-added products to develop new functional foods. In this context, the (typically discarded) aerial parts of tomato plants (Solanum lycopersicum L. var. cerasiforme), were studied as new sources of natural bioactive compounds, focusing the extraction and encapsulation (using spray drying with maltodextrin as the encapsulant) of chlorophylls. The encapsulated natural colorant was subsequently incorporated into mascarpone cheese to assess its stability and effect on nutritional and antioxidant properties. The obtained extracts were mainly characterized by high concentrations of bioactive compounds, particularly quercetin-3-O-deoxyhexoside (14.4 ± 0.3 mg/g). The colorant imparted a greener hue to the mascarpone (a* –6.0 ± 0.05 vs. –1.7 ± 0.05 in control, p < 0.001) and maintained antioxidant activity (OxHLIA EC₅₀ = 1440 ± 72 to 1166 ± 66 μg/mL, p = 0.030) without altering the nutritional profile (p > 0.05). Moreover, no cytotoxicity was observed, and the fatty acid composition remained unchanged. Accordingly, the studied encapsulated colorant might be used as a functional ingredient in other dairy products, imparting an attractive color while preserving nutritional integrity. In conclusion, the incorporation of TAPC is an effective strategy to enrich dairy products with natural pigments and bioactive compounds without compromising quality. Future research is needed to explore its application in other food matrices and assess long-term storage effects.
- Banana Peels as Substrate for Lactic Acid Production: Upstream Fermentation BioprocessPublication . Pedrosa, Mariana C.; Heleno, Sandrina A.; Alvarez, Cristina; Susmozas, Ana; Ballesteros, Ignacio; Pintado, Manuela; Barros, Lillian; Carocho, MárcioPurpose Banana peels account for around 30-40% of the banana's weight and represent an industrial waste. This biomass can be used as an eco-friendly solution for biotechnological bioprocesses. Still, due to the fibrous nature of banana peels, pretreatment becomes essential to enhance the effectiveness of enzymes on the hydrolysis of complex carbohydrates. This study aims to determine the best pretreatment and enzymatic hydrolysis conditions to produce a fermentation substrate suitable for producing lactic acid from the peels.MethodsA diluted H2SO4 (0.5% and 0.25%) was used in an autoclave for 10 min at 121 degrees C. The pretreated material was subjected to several enzymatic hydrolysis tests in which two variables were evaluated for their influence: solid load (10, 15 and 20%), and H2SO4 concentration (0.5 and 0.25% v/v). Commercial enzymes (cellulolytic enzyme mixtures and pectinase) were used.ResultsAll enzymatic hydrolysis yields of cellulose referring to glucose released in the hydrolysates surpassed 60% in all the conditions tested after pretreatment. After evaluating the pretreatment efficiency, the ideal parameters were defined as 0.25% H2SO4, and cellulolytic enzyme mixtures with 15 and 20% solid load. Subsequently, a screening was carried out in MRS + broth with the most suitable pH and temperature conditions for lactic acid production by Lacticaseibacillus rhamnosus.ConclusionsThe results showed the potential of BP medium for lactic acid production, with yields of 0.91 g/g sugar in sugar-containing media from enzymatic hydrolysis at 15% solid load and 0.82 g/g sugar in media from 20% solid load assays.
- A breakthrough on bread formulation: natural mineral water as a novel functional ingredientPublication . Ferreira, Fernanda; Ueda, Jonata Massao; Guimarães, Rafaela; Heleno, Sandrina A.; Carocho, Márcio; Lemos, André; Pintado, Manuela; Alves, Maria José; Barros, LillianThe food industry has a significant impact on global economy. The development of new products and food ingredients that improve the nutritional, functional, and organoleptic properties play a critical role in the discovery of higher-quality products. Bread is one of the most common foods found in most people's daily diets. Water plays a crucial role in its preparation, since it hydrates the flour, amide, and proteins. In this way, natural mineral waters (thermal and carbonated) are rich in trace elements, presenting great potential in the development of new enriched products [1,2] . The main purpose of this study was to create bread, biju, and chapata formulations that used natural mineral water instead of regular water to better understand the impact of different liquids on the physicochemical properties and centesimal composition of bread (thermal and carbonated). After cooking, parameters such as carbohydrates, ash, fat, protein, salt content, pH, water activity, minerals and fatty acids were determined. With regards to the centesimal composition, the carbonated and thermal biju breads showed significant increase in the energy value when compared to normal bread. Although the chapata thermal bread had the highest protein and salt content, the energy value remained unchanged. Noteworthy, analyzing the fatty acid profile for the thermal biju bread there was a significant decrease in the PUFA content. Considering the chapata bread (carbonated and thermal) highest contents of mainly SFA and MUFA were found. When comparing normal bread with carbonated and thermal chapata breads in pH parameter, these breads showed the highest values, while the water activity increased in the carbonated and thermal biju bread. Finally, a highest total mineral content, was observed in the carbonated and thermal biju bread. Overall, the results suggest that thermal and carbonated waters could be useful ingredients in the development of novel functional products
- A Comprehensive Review of Fish Protein Hydrolysates Targeting Pet Food FormulationsPublication . Ribeiro, Tânia Isabel Bragança; Maia, Margarida R.G.; Fonseca, António J.M.; Marques, Bianca; Caleja, Cristina; Rosa, Ana; Martins, Rui; Almeida, André; Mota, Maria J.; Aires, Tiago; Rocha, Cristina M.R.; Teixeira, José António; Cabrita, Ana R.J.; Barros, Lillian; Pintado, ManuelaThe fish industry generates significant amounts of fish by- and co-products (FBCPs) annually, projected to reach 160.8 million tonnes by 2030. This growth highlights the urgent need for sustainable FBCP management and an opportunity to improve the sector’s environmental sustainability. Fish protein hydrolysates (FBCPHs) and bioactive peptides (BPs) derived from these FBCPs are gaining recognition in the pet food sector for their nutritional and bioactives benefits. FBCPHs, primarily sourced from category 3 by-products unsuitable for human consumption, could significantly enhance the economic viability of both industries. This review analyzes production processes, highlighting the benefits and challenges of enzymatic hydrolysis and reviewed emerging technologies such as subcritical water hydrolysis (SWH), which are promising sustainable alternatives by enhancing extraction efficiency and reducing energy consumption. The review explores FBCPHs’ applications in pet food, focusing on beneficial biological activities (e.g. antioxidant, prebiotic, neuroprotective). Findings show FBCPHs have significant potential in pet food formulations, providing palatability, hypoallergenic benefits, and addressing health concerns like gastrointestinal disorders and stress-related behaviors. However, further research is required to optimize production processes, scale industrial application, and ensure regulatory compliance. In conclusion, FBCPHs present a valuable solution for promoting sustainability, improving pet nutrition, and supporting the circular economy.
- Docking studies in target proteins involved in mechanisms of antibacterial action: extending the knowledge on standard antibiotics to mushrooms antimicrobial compoundsPublication . Alves, Maria José; Froufe, Hugo J.C.; Costa, Ana F.T.; Santos, Anabela F.; Oliveira, Liliana G.; Osório, Sara R.M.; Abreu, Rui M.V.; Pintado, Manuela; Ferreira, Isabel C.F.R.In the present work, the knowledge on target proteins of standard antibiotics was extended to antimicrobial mushroom compounds. Docking studies were performed for 34 compounds in order to evaluate their affinity to bacterial proteins that are known targets for some antibiotics with different mechanism of action: inhibitors of cell wall synthesis, inhibitors of protein synthesis, inhibitors of nucleic acids synthesis and antimetabolites. After validation of the molecular docking approach, virtual screening of all the compounds was performed against penicillin binding protein 1a (PBP1a), alanine racemase (Alr), D-alanyl-D-alanine synthetase (Ddl), isoleucyl-tRNA sinthetase (IARS), DNA gyrase subunit B, topoisomerase IV (TopoIV), dihydropteroate synthetase (DHPS) and dihydrofolate reductase (DHFR) using AutoDock4. Overall, it seems that for the selected mushroom compounds (namely, enokipodins, ganomycins and austrocortiluteins) the main mechanism of the action is the inhibition of cell wall synthesis, being Alr and Ddl probable protein targets.