Percorrer por autor "Duarte, Ana Paula"
A mostrar 1 - 10 de 39
Resultados por página
Opções de ordenação
- Antimicrobial, antibiofilm and cytotoxic activities of Hakea sericea Schrader extractsPublication . Luís, Ângelo; Breintenfeld, Luiza; Ferreira, Susana; Duarte, Ana Paula; Domingues, F.C.Background: Hakea sericea Schrader is an invasive shrub in Portuguese forests. Objective: The goal of this work was to evaluate the antimicrobial activity of H. sericea extracts against several strains of microorganisms, including the ability to inhibit the formation of biofilms. Additionally the cytotoxic properties of these extracts, against human cells, were assessed. Materials and Methods: The antimicrobial activity of the methanolic extracts of H. sericea was assessed by disk diffusion assay and Minimum Inhibitory Concentration (MIC) value determination. The antibiofilm activity was determined by quantification of total biofilm biomass with crystal violet. Cytotoxicity was evaluated by hemolysis assay and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test. Results: For Gram-positive bacteria, MIC values of H. sericea methanolic extracts ranged between 0.040 and 0.625 mg/mL, whereas the fruits extract yielded the lowest MIC for several strains of microorganisms, namely, S. aureus, B. cereus, L. monocytogenes and clinical methicillin-resistant S. aureus (MRSA). Stems and fruits extract at 2.5 mg/mL effectively eradicated the biofilm of S. aureus ATCC 25923, SA 01/10 and MRSA 12/10. Regarding leaves extract, hemolysis was not observed, and in the case of stems and fruits, hemolysis was verified only for higher concentrations, suggesting its low toxicity. Fruits extract presented no toxic effect to normal human dermal fibroblasts (NHDF) cells however for concentrations of 0.017 and 0.008 mg/mL this extract was able to decrease human breast adenocarcinoma cells (MCF-7) viability in about 60%, as MTT test results had confirmed. This is a clearly demonstrator of the cytotoxicity of this extract against MCF-7 cells.
- Antioxidant and antimicrobial activity and potential of heather (Erica spp.) extracts in the control of Listeria monocytogenesPublication . Santos, Anabela; Luís, Ângelo; Ferreira, Susana; Duarte, Ana PaulaIn this work, heather and its flowers were studied regarding their antioxidant and antimicrobial activities. Plants were subjected to ultrasound‐assisted methanolic extraction followed by fractionation. A phytochemical characterisation of extracts content in total phenols and flavonoids, and their antioxidant activity was performed. The antimicrobial activity was evaluated through the determination of minimum inhibitory concentration and by bioautography. Following, studies on the antilisterial potential were carried out by: time‐kill curves, inhibition of biofilm formation and tolerance of Listeria monocytogenes to adverse conditions. The results evidenced the antioxidant activity in both extracts, as well as, the antimicrobial activity against Gram‐positive bacteria. Concerning the evaluation of the antilisterial potential, a bacteriostatic behaviour and inhibition of biofilms formation ability were observed. Listeria monocytogenes showed an increased susceptibility to adverse conditions when preincubated with extracts. Thus, heather and its flowers may be a source of new compounds with antilisterial activity potential.
- Assessment of the Antimicrobial Activity of L. and (L.) DC Extracts and Their Synergistic Potential with Conventional Antibiotics AgainstPublication . Coimbra, Alexandra; Luís, Ângelo; Gaspar, Pedro Dinis; Ferreira, Susana; Duarte, Ana Paula; Hadjikakou, Sotiris K.This study aimed to evaluate the antibacterial activity of L. and (L.) DC extracts against , including methicillin-resistant (MRSA) strains. To this end, assays were conducted to assess killing kinetics, antibiotic combination effects, modulatory effects on ethidium bromide, inhibition of quorum sensing, and biofilm formation. extract demonstrated the strongest activity, with MIC values ranging from 7.8 to 62.5 µg/mL. When combined with antibiotics such as ampicillin, ciprofloxacin, or vancomycin, the extracts of and predominantly exhibited synergistic (FICI value ≤ 0.5) or additive effects (0.5 < FICI ≤ 1), with some combinations resensitizing resistant strains. The aerial parts of displayed modulatory effects on ethidium bromide MIC, reducing the concentration from 32 to 8 µg/mL, suggesting efflux pump inhibitory activity. In addition, this extract displayed slight quorum-sensing inhibition at a concentration of 125 µg/mL. Moreover, and extracts inhibit the formation of biofilm by strains, even at subinhibitory concentrations (0.5× and 0.25× MIC). The presence of compounds such as myricetin 3 -galactoside, catechin derivatives, gallic acid, kaempferol, and chlorogenic acid in the extracts may contribute to their anti- activity. These results demonstrated the dual antimicrobial and antivirulence potential of and extracts, highlighting their promise as therapeutic agents or adjuvants against These extracts can be promising candidates for further studies on the development of novel strategies targeting multiple pathogenic pathways.
- Assessment of the Bioaccessibility and Bioavailability of the Phenolic Compounds of Prunus avium L. by in Vitro Digestion and Cell ModelPublication . Gonçalves, Joana; Ramos, Rodrigo; Luís, Ângelo; Rocha, Sandra; Rosado, Tiago; Gallardo, Eugenia; Duarte, Ana PaulaThe fruit of Prunus avium L., commonly known as sweet cherry, is an excellent source of phytochemicals, namely, phenolic compounds. This study aims to determine in vitro the bioavailability and the bioactivity of phenolic compounds present in cherries. Caco-2 cells were used, and the permeability and integrity of the monolayer formed were investigated. After incubation, the phenolic compounds that permeabilized the cell monolayer were quantified using a high-performance liquid chromatography–diode array detector, and the antioxidant activity was evaluated by the 1,1-diphenyl-2-picrylhydrazyl method. The results demonstrated that the phenolic compounds of sweet cherries after undergoing a simulated digestion were absorbed by the cellular barrier, becoming bioavailable. Contrary to what was found after incubation with the in vitro digested extract, the integrity of the cell monolayer was altered and its permeability increased upon incubation with the sweet cherry phenolic extract. Regarding the antioxidant activity, it was verified that this decreased after the absorption by the cellular monolayer. This study suggests that digestion is an indispensable process for absorption because without it the phenolic content of the food matrix does not become bioaccessible.
- Ayahuasca Beverages: Phytochemical Analysis and Biological PropertiesPublication . Gonçalves, Joana; Luís, Ângelo; Gradillas, Ana; García, Antonia; Restolho, José; Fernández, Nicolás; Domingues, F.C.; Gallardo, Eugenia; Duarte, Ana PaulaAyahuasca is a psychoactive beverage, originally consumed by indigenous Amazon tribes, of which consumption has been increasing worldwide. The aim of this study was to evaluate the phytochemical profile, as well as the antioxidant, anti-inflammatory and antimicrobial properties of decoctions of four individual plants, a commercial mixture and four mixtures of two individual plants used in the Ayahuasca preparation. For this purpose, a phytochemical characterization was performed, determining the content of flavonoids, total phenolic compounds, and analyzing the phenolic profile. Besides, 48 secondary metabolites were investigated by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q/TOF-MS) and their concentration estimated with real standards when present. The antioxidant activity was evaluated by both the β-carotene bleaching test and DPPH free radical scavenging assay, and the anti-inflammatory activity was determined by a protein denaturation method. Finally, the antimicrobial properties were evaluated using the disc diffusion assay, resazurin microtiter method, anti-quorum sensing and anti-biofilm activity assays. The obtained results showed that, in general, the samples have a high content of phenolic compounds and flavonoids with noticeable differences, reflecting on remarkable antioxidant and anti-inflammatory activities. Significant antimicrobial properties were also observed, with emphasis on the effect of B. caapi and P. harmala on planktonic and biofilm cells of A. baumannii, inhibiting both the biofilm formation and the production of violacein pigment.
- Bark residues valorization potential regarding antioxidant and antimicrobial extractsPublication . Neiva, Duarte; Luís, Ângelo; Gominho, Jorge; Domingues, Fernanda C.; Duarte, Ana Paula; Pereira, HelenaBark residual side streams from industries (Eucalyptus globulus—Eg and Picea abies—Pa) or from control of invasive species in Mediterranean countries (Acacia melanoxylon—Am and Acacia dealbata—Ad) are burned for energy production, although their high content of extractable compounds points to a possible valorization as sources of phytochemicals with antioxidant and antimicrobial activities. Non-polar and polar extracts were obtained, and their phenolic contents, antioxidant activity, antiquorum sensing and antimicrobial potential against several human pathogenic microbes (nine bacteria and two yeasts) were determined. Extraction yield ranged from 0.5 to 37% of barks dry weight varying with species and solvent used, and both water and ethanol extracts presented strong or very strong scavenging antioxidant ability. Eg and Pa non-polar extracts showed the lowest minimum inhibitory concentration for gram-positive bacteria (0.04–1.25 mg/mL), while Ad presented the best results among polar extracts regarding bacteria (0.16 mg/mL for K. pneumoniae) and yeast strains (0.02–0.04 mg/mL). Non-polar extracts showed great response against both Candida species (MIC=0.04–0.63 mg/mL). Each extract had diferent antimicrobial activity showing that species and solvents can be used to tailor compounds to target specifc pathogens. Information regarding these bioactive extracts from residual forest side streams can provide possible utilization routes for natural compounds recovery prior to combustion.
- Behaviour of two main portuguese wood species towards enzymatic hydrolysisPublication . Spiridon, Iuliana; Belgacem, Mohamed Naceur; Duarte, Ana PaulaThis paper presents the influence of cellulolytic and hemicellulolytic enzymes on the papermaking properties of pulps from Eucalyptus globulus and Pinus pinaster wood species from Portugal. It was shown that these enzymes increased the delignification efficiency and degraded the cellulose macromolecules, having effects on the fiber strength. Thus, it was found that these treatments decreased strongly the burst index, but increased significantly the tearing properties. The zero span tensile strength was also affected, especially for Eucalyptus globulus pulps. Finally, these treatments were found to increase the brightness of the treated pulps.
- Bioactive Potential of Wild Plants from Gardunha Mountain: Phytochemical Characterization and Biological ActivitiesPublication . Coimbra, Alexandra; Gallardo, Eugenia; Luís, Ângelo; Gaspar, Pedro Dinis; Ferreira, Susana; Duarte, Ana Paula; Adriana, IrinelThe plants used in folk medicine have been increasingly studied to identify their bioactive properties. Therefore, this study aimed to assess the bioactivity of the hydroethanolic extracts of plants collected in Gardunha Mountain, Portugal. Seven abundant and representative wild plants were studied: , , , , , , and . The phytochemical composition of the extracts was determined by UHPLC-timsTOF-MS and by spectrophotometric methods. The antioxidant, in vitro anti-inflammatory and antimicrobial activity and the biocompatibility of the extracts were tested. The extracts were predominantly composed of flavonoids and phenolic acids, such as gallic acid, neochlorogenic acid and quercetin glycosides. The extracts demonstrated very strong antioxidant activity related to scavenging free radicals (AAI = 2.84 and 2.93). Regarding antimicrobial activity, the extract exhibited inhibitory effects, particularly against Gram-positive bacteria and yeasts (MIC = 0.008-0.5 mg/mL). The , , and extracts showed low cytotoxicity (viability > 70%) in the highest concentration tested. These findings highlight and as promising sources of novel bioactive compounds, particularly antimicrobials in controlling microbial growth and promoting associated health benefits, and underscore the value of traditional medicinal plants as a guide for pharmacological studies.
- Cannabis and Its Secondary Metabolites: Their Use as Therapeutic Drugs, Toxicological Aspects, and Analytical DeterminationPublication . Gonçalves, Joana; Rosado, Tiago; Soares, Sofia; Simão, Ana; Caramelo, Débora Almeida; Luís, Ângelo; Fernández, Nicolás; Barroso, Mário; Gallardo, Eugenia; Duarte, Ana PaulaAlthough the medicinal properties of Cannabis species have been known for centuries, the interest on its main active secondary metabolites as therapeutic alternatives for several pathologies has grown in recent years. This potential use has been a revolution worldwide concerning public health, production, use and sale of cannabis, and has led inclusively to legislation changes in some countries. The scientific advances and concerns of the scientific community have allowed a better understanding of cannabis derivatives as pharmacological options in several conditions, such as appetite stimulation, pain treatment, skin pathologies, anticonvulsant therapy, neurodegenerative diseases, and infectious diseases. However, there is some controversy regarding the legal and ethical implications of their use and routes of administration, also concerning the adverse health consequences and deaths attributed to marijuana consumption, and these represent some of the complexities associated with the use of these compounds as therapeutic drugs. This review comprehends the main secondary metabolites of Cannabis, approaching their therapeutic potential and applications, as well as their potential risks, in order to differentiate the consumption as recreational drugs. There will be also a focus on the analytical methodologies for their analysis, in order to aid health professionals and toxicologists in cases where these compounds are present.
- Characterization and evaluation of Achillea erba-rotta subsp. moschata (Wulfen) I. Richardson and Achillea millefolium L. as potential ingredients for skin applicationsPublication . Marengo, Arianna; Cagliero, Cecilia; Sgorbini, Barbara; Menzio, Giulia ; Fusani, Pietro; Duarte, Ana Paula; Luís, Ângelo Filipe Santos ; Fonseca, Lara R. S.; Feijó, Mariana Pombal ; Socorro, Sílvia; Bertea, Cinzia Margherita; Rubiolo, PatriziaEthnopharmacological relevance: Despite their different geographical distribution Achillea millefolium L. and Achillea erba-rotta subsp. moschata (Wulfen) I. Richardson are characterized by a consolidated traditional knowledge. Although this is not their first traditional use, they have also long been used as ingredients for skin healing and skin care. Aim of the study: The aim of this work was to characterize the two Achillea species from a chemical and biomolecular point of view in order to find a simple tool for their discrimination. At the same time, the biological activity of the extracts as inhibitors of the enzymes tyrosinase and elastase and as antimicrobial agents was evaluated. Materials and methods: The biomolecular analysis was performed on the DNA region trnL-F. The hydroalcholic (EtOH50 %) extracts were quali-quantitatively characterized by HPLC-PDA-MS/MS and tested for their inhibitory effect on the enzymes tyrosinase and elastase as well as for their antimicrobial activity. Cytotoxicity towards human fibroblasts was tested to evaluate their safety for potential applications. Results: Restriction Fragment Length Polymorphism (RFLP) analysis of the trnL-F DNA region was a useful tool for species discrimination. Both extracts are rich in polyphenols and showed moderate tyrosinase (26-5 %) and elastase (22-14 %) inhibitory activity at 17 μg/mL. They were also able to inhibit the growth of the bacteria and yeasts studied, generally exhibiting cytotoxicity to human fibroblasts at concentrations of 500 μg/mL or higher. Conclusions: The hydroalcoholic extracts from the aerial parts of A. millefolium and A. erba-rotta subsp. moschata can be considered good candidates for the cosmetic and health sectors, also supporting the traditional use of these species in the treatment of skin diseases.