Browsing by Author "Faleiro, Maria Leonor"
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- 1-Methylcyclopropene and lemongrass essential oil nanocoatings effect on the preservation of cold stored ‘Rocha’ pearPublication . Gago, Custódia; Guerreiro, Adriana; Cruz, Sandra; Martins, Nuno; Cabrita, Maria João; Miguel, Maria; Faleiro, Maria Leonor; Antunes, Maria DulceThe effects of coating 'Rocha' pear with alginate-based nanoemulsions enriched with lemongrass essential oil (LG) was evaluated and compared to the usual 1-MCP treatment. Fruit were treated with 1-MCP (312 nL L-1) or coated with nanoemulsions: sodium alginate 2 % (w/w) + lemongrass essential oil 1.25 % (w/w) (LG 1.25 %) or lemongrass essential oil 2.5 % (w/w) (LG 2.5 %). Then, fruit were stored at 0 degrees C and 90-95 % relative humidity (RH), for eight months. Fruit samples were collected at harvest and after two, four, six and eight months of cold storage, and then transferred to shelf-life at 22 degrees C. Upon removal and after 7 d shelf-life, fruit symptoms of superficial scald and internal browning, ethylene production, color CIE (L*, hue), firmness, soluble solids content (SSC), titratable acidity (TA), weight loss, electrolytic leakage (EL), antioxidant activity and fatty acids of pear peel, microbial growth and sensory analyses were evaluated. Coatings and 1-MCP reduced fruit color evolution and preserved better firmness than control. Coatings and 1-MCP did not affect SSC and TA. Treatments did not influence the sensory quality. Microbial growth was within the safety limits in all treatments. Treatments with 1-MCP and LG-nanoemulsions were similarly efficient to reduce superficial scald, nevertheless the LG-nanoemulsions showed higher internal disorders after 8 months of storage and LG 2.5 % had higher decay at the same period, similar to control. 1-MCP treated fruit had the lowest softening rate after shelf-life up to 4 months and LG 2.5 % showed higher weight loss. Also, ethylene production was higher in control and LG 1.25 % up to 6 months plus shelf-life, while after 8 months there was no difference among treatments. This study suggests that 1-MCP is the most efficient for preserving quality of 'Rocha' pear for 8 months, while up to 6 months the best effect is obtained with LG 1.25 % nanocoatings.
- Adaptation of Listeria monocytogenes in a simulated cheese medium: effects on virulence using the Galleria mellonella infection modelPublication . Schrama, Denise; Helliwell, N.; Neto, L.; Faleiro, Maria LeonorThe aim of this study was to evaluate the effect of the acid and salt adaptation in a cheese-based medium on the virulence potential of Listeria monocytogenes strains isolated from cheese and dairy processing environment using the Galleria mellonella model. Four L.monocytogenes strains were exposed to a cheese-based medium in conditions of induction of an acid tolerance response and osmotolerance response (pH 5 center dot 5 and 3 center dot 5% w/v NaCl) and injected in G.mellonella insects. The survival of insects and the L.monocytogenes growth kinetics in insects were evaluated. The gene expression of hly, actA and inlA genes was determined by real-time PCR. The adapted cells of two dairy strains showed reduced insect mortality (P<0 center dot 05) in comparison with nonadapted cells. Listeria monocytogenes Scott A was the least virulent, whereas the cheese isolate C882 caused the highest insect mortality, and no differences (0 center dot 05) was found between adapted and nonadapted cells. The gene expression results evidenced an overexpression of virulence genes in cheese-based medium, but not in simulated insect-induced conditions. Our results suggest that adaptation to low pH and salt in a cheese-based medium can affect the virulence of L.monocytogenes, but this effect is strain dependent. Significance and Impact of the Study In this study, the impact of adaptation to low pH and salt in a cheese-based medium on L.monocytogenes virulence was tested using the Wax Moth G.mellonella model. This model allowed the differentiation of the virulence potential between the L.monocytogenes strains. The effect of adaptation on virulence is strain dependent. The G.mellonella model revealed to be a prompt method to test food-related factors on L.monocytogenes virulence.
- Anti-acetylcholinesterase, antidiabetic, anti-inflammatory, antityrosinase and antixanthine oxidase activities of Moroccan propolisPublication . EL-GEUNDOUZ, Soukaina; S, Azza; Lyoussi, Badiaa; Antunes, Maria Dulce; Faleiro, Maria Leonor; Miguel, MariaBiological properties of Moroccan propolis have been scarcely studied. In the present work, the total phenols and flavonoids from 21 samples of propolis collected in different places of Morocco or 3 supplied in the market were determined, as well as the invitro capacity for inhibiting the activities of acetylcholinesterase, -glucosidase, -amylase, lipoxygenase, tyrosinase, xanthine oxidase and hyaluronidase. The results showed that samples 1 (region Fez-Boulemane, Sefrou city) (IC50=0.065, 0.006, 0.020, 0.050, 0.014mgmL(-1)) and 23 (marketed) (IC50=0.018, 0.002, 0.046, 0.037, 0.008mgmL(-1)) had the best invitro capacity for inhibiting the -amylase, -glucosidase, lipoxygenase, tyrosinase and xanthine oxidase activities, respectively. A negative correlation between IC50 values and concentration of phenols, flavones and flavanones was found. These activities corresponded to the generally higher amounts of phenols and flavonoids. In the same region, propolis samples have dissimilar phenol content and enzyme inhibitory activities.
- Antibacterial activity of propolis extracts from the south of PortugalPublication . Oliveira, Ana; Ferreira, Ana Luisa; Nunes, Susana; Dandlen, Susana; Miguel, Maria; Faleiro, Maria LeonorTo examine the antibacterial activity of diverse extracts of propolis harvested at winter and spring from several locations of Algarve, Portugal, against Gram-negative and Gram-positive bacteria was the main goal of the present work. For such, the antibacterial activity was determined by agar diffusion. The results showed that all tested bacterial strains showed susceptibility to diluted propolis extracts and in a dose-dependent manner. Two propolis samples collected at springtime showed higher antibacterial activity, in comparison with samples harvested at wintertime. Ethanolic and methanolic extracts have a very similar activity (P<0.05). Helicobacter pylori strains J99 and 26695 were the most susceptible strains to the tested extracts (33.67 +/- 2.52 mm and 35.67 +/- 0.58mm, respectively). This study constitutes the first approach of the biological activities of Portuguese propolis from the Algarve region and evidences its potential use to combat bacterial infections, in particular against the gastric pathogen H. pylori.
- Antioxidant, Anti-inflammatory and Anti-hyperglycaemic Activities of Essential Oils from Thymbra capitata, Thymus albicans, Thymus caespititius, Thymus carnosus, Thymus lotocephalus and Thymus mastichina from PortugalPublication . S, Azza; EL-GEUNDOUZ, Soukaina; Miguel, Maria; Antunes, Maria Dulce; Faleiro, Maria Leonor; Correia, A. Isabel; Figueiredo, A. CristinaThe in vitro antioxidant, anti-inflammatory, anti-hyperglycaemic, and anti-acetylcholinesterase activities of the essential oils (EOs) isolated from six Lamiaceae species (Thymbra capitata, Thymus albicans, Th. caespititius, Th. carnosus, Th. lotocephalus and Th. mastichina) grown in Portugal, were evaluated. Th. caespititius and T. capitata carvacrol/thymol-rich EOs showed the best capacity for preventing lipid peroxidation, and scavenging the 2,2 '-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and peroxyl free radicals, as well as for inhibiting lipoxygenase and alpha-amylase. However, Th. caespititius and Th. lotocephalus 1,8-cineole and linalool rich EOs were the best inhibitors of alpha-glucosidase. T. capitata, Th. lotocephalus and Th. albicans EOs were the most active for inhibiting acetylcholinesterase. Th. caespititius and Th. mastichina EOs were the main scavengers of nitric oxide (NO) radicals. The comparison between the present data with a survey of the existing literature on the in vitro biological activities of the essential oils isolated from the same species from Portuguese origin, using other methodologies, showed some differences. For instance the use of two oxidizable substrates (egg yolk and lecithin liposomes) led to distinct results mainly for those samples with relatively low activity. In addition, the EOs capacity for scavenging peroxyl radicals was also influenced by the presence of cyclodextrins, as a synergism seemed to occur between EOs and those carbohydrates.
- Changes in the chemical parameters during the production of água-mel from PortugalPublication . Miguel, Maria; AAZZA, Smail; Antunes, Maria Dulce; Faleiro, Maria LeonorAgua-mel is a honey-based traditional product typically produced in southern Portugal. The evolution of some parameters during its production using two distinct containers (aluminium and stainless steel with a water cooling system) and two heating sources (gas heating and electricity) were evaluated. All parameters, except moisture, increased over time, reaching a 'plateau' after 8 h of heating. Moisture, free acidity, HMF (hydroxymethylfurfural), colour, melanoidins, phenols and glucose depended on the producer and procedure for obtaining agua-mel. Kinetic parameters and correlation coefficients were determined. In general, changes in parameters during agua-mel production followed zero- and/or first-order kinetics, depending on the producer and heating system.
- Chemical characterization and biological properties assessment of Euphorbia resinifera and Euphorbia officinarum Moroccan PropolisPublication . Boutoub, Oumaima; El-Guendouz, Soukaina; Matos, Isabel; El Ghadraoui, Lahsen; Costa, Maria Clara; Carlier, Jorge; Faleiro, Maria Leonor; Figueiredo, Ana Cristina; Estevinho, Letícia M.; Miguel, MariaAlthough the plants of the genus Euphorbia are largely exploited by therapists in Morocco, the composition and antibacterial activities of propolis from these plants are still unknown. To address this gap, this study aimed to characterize the pollen type, the volatile compounds, and the phenolic and mineral profiles of three Euphorbia propolis samples collected in Morocco and evaluate their antimicrobial activities. The minimum inhibitory concentration of the propolis samples was determined by the microdilution method, and the anti-adherence activity was evaluated by the crystal violet assay. The examination of anti-quorum-sensing proprieties was performed using the biosensor Chromobacterium violaceum CV026. Pollen analysis revealed that Euphorbia resinifera pollen dominated in the P1 sample (58%), while E. officinarum pollen dominated in the P2 and P3 samples (44%). The volatile compounds were primarily composed of monoterpene hydrocarbons, constituting 35% in P1 and 31% in P2, with α-pinene being the major component in both cases, at 16% in P1 and 15% in P2. Calcium (Ca) was the predominant mineral element in both E. resinifera (P1) and E. officinarum (P2 and P3) propolis samples. Higher levels of phenols, flavonoids and dihydroflavonoids were detected in the E. officinarum P2 sample. The minimum inhibitory concentration (MIC) value ranged from 50 to 450 µL/mL against Gram-positive and Gram-negative bacteria. Euphorbia propolis displayed the ability to inhibit quorum sensing in the biosensor C. violaceum CV026 and disrupted bacterial biofilm formation, including that of resistant bacterial pathogens. In summary, the current study evidences the potential use of E. officinarum propolis (P2 and P3) to combat important features of resistant pathogenic bacteria, such as quorum sensing and biofilm formation.
- Edible coatings enriched with essential oils on apples impair the survival of bacterial pathogens through a simulated gastrointestinal systemPublication . Vieira, Ana; Guerreiro, Adriana; Antunes, Maria Dulce; Miguel, Maria; Faleiro, Maria LeonorEdible coatings supplemented with essential oil components have been investigated to control spoilage microorganisms. In this study, the survival of Listeria monocytogenes and Salmonella enterica serovar Typhimurium on apples treated with edible coatings based on sodium alginate (2%) (ECs) and supplemented with essential oil components, namely eugenol (Eug) at 0.2% or in combination with 0.1% (v/v) of Eug and citral (Cit) at 0.15% was determined. Both bacterial pathogens were exposed on apples treated with ECs supplemented with Eug or Eug + Cit and challenged with gastrointestinal fluids and their survival was examined. Both pathogens were able to survive on the surface of 'Bravo de Esmolfe' apple. The use of ECs in fresh-cut fruits impaired the survival of both bacterial populations over 72 h at 4 °C. The exposure of the pathogens on apples with ECs supplemented with Eug and Cit and challenged with gastrointestinal fluids significantly reduced their survival. This study evidences that the use of alginate edible coating enriched with Eug or the combination of Eug and Cit can contribute to the safer consumption of minimally processed fruits.
- Establishment of an induced pluripotent cell line (ABCRIi001-A) from an elderly female for ageing researchPublication . Esteves, Filipa; Vilhena Catarino Brito, David; Rajado, Ana Teresa; Silva, Nádia; Apolónio, Joana; Roberto, Vânia; Andrade, Raquel; Calado, Sofia; Faleiro, Maria Leonor; Albuquerque Andrade de Matos, Carlos Adriano; Marques, Nuno; Marreiros, Ana; Nzwalo, Hipólito; Pais, Sandra; Palmeirim, Isabel; Simãoa, Sónia; Joaquim, Natércia; Miranda, Rui; Pêgas, António; Raposo, Daniela Marques; Sardo, Ana; Araújo, Inês; Nóbrega, Clévio; Castelo-Branco, Pedro; Bragança, JoséHuman induced pluripotent stem cells (hiPSCs) hold promises to model and understand human diseases, including those associated with ageing. Here, we describe ABCRIi001-A, a hiPSC line generated from peripheral blood mononuclear cells (PBMCs) of a 79-year-old female enrolled in a study for development of an ageing score (ALFA Score). PBMCs were reprogrammed using three Sendai virus-based reprogramming vectors (hKOS, hc-Myc, and hKlf4). ABCRIi001-A showed normal morphology and karyotype, viral clearance, absence of genomic aberrations, and their pluripotency was confirmed by expression of pluripotency-related markers and their ability to differentiate into the three germ layers. ABCRIi001-A is valuable for ageing-related studies.
- Foeniculum vulgare Essential Oils: Chemical Composition, Antioxidant and Antimicrobial ActivitiesPublication . Miguel, Maria Graça; Cruz, Claudia; Faleiro, Maria Leonor; Simoes, M. T. F.; Figueiredo, A. C.; Barroso, J. G.; Pedro, L. G.The essential oils from Foeniculum vulgare commercial aerial parts and fruits were isolated by hydrodistillation, with different distillation times (30 min, I h, 2 h and 3 h), and analyzed by GC and GC-MS. The antioxidant ability was estimated using four distinct methods. Antibacterial activity was determined by the agar diffusion method. Remarkable differences, and worrying from the quality and safety point of view, were detected in the essential oils. trans-Anethole (31-36%), alpha-pinene (14-20%) and limonene (11-13%) were the main components of the essentials oil isolated from F. vulgare dried aerial parts, whereas methyl chavicol (= estragole) (79-88%) was dominant in the fruit oils. With the DPPH method the plant oils showed better antioxidant activity than the fruits oils. With the TBARS method and at higher concentrations, fennel essential oils showed a pro-oxidant activity. None of the oils showed a hydroxyl radical scavenging capacity >50%, but they showed an ability to inhibit 5-lipoxygenase. The essential oils showed a very low antimicrobial activity. In general, the essential oils isolated during 2 h were as effective, from the biological activity point of view, as those isolated during 3 h.