Insights into the antimicrobial potential of acorn extracts (Quercus ilex and Quercus suber)

Acorns, frequently left uncollected in the fields, have been a part of the traditional medicine of different cultures. Among the different properties associated with them, their antimicrobial potential is of particular importance. However, this characterization has long been superficial and has not ventured into other topics such as biofilm inhibition. Thus, the current work aimed to characterize the antimicrobial and antibiofilm potential of an array of phenolic rich extracts attained from acorns, two different acorn varieties Q. ilex and Q. suber, considering the fruit and shell separately, fresh and after heat-treating the acorns to aid in the shelling process. To accomplish this, the extracts’ capacity to inhibit an array of different microorganisms was evaluated, the minimum bactericidal concentration (MBC) was determined, time-death curves were drawn whenever an MBC was found and the antibiofilm potential of the most effective extracts was drawn. The overall results showed that Gram-positive microorganisms were the most susceptible out of all the microorganisms tested, with the shell extracts being the most effective overall, exhibiting bactericidal effect against S. aureus, B. cereus and L. monocytogenes as well as being capable of inhibiting biofilm formation via the two S. aureus strains. The attained results demonstrated that acorn extracts, particularly shell extracts, pose an interesting antimicrobial activity which could be exploited in an array of food, cosmetic and pharmaceutical applications.info:eu-repo/semantics/publishedVersio

Selective activity of an anthocyanin-rich, purified blueberry extract upon pathogenic and probiotic bacteria

Blueberry extracts have been widely recognized as possessing antimicrobial activity against several potential pathogens. However, the contextualization of the interaction of these extracts with beneficial bacteria (i.e., probiotics), particularly when considering the food applications of these products, may be of importance, not only because their presence is important in the regular gut microbiota, but also because they are important constituents of regular and functional foodstuffs. Therefore, the present work first sought to demonstrate the inhibitory effect of a blueberry extract upon four potential food pathogens and, after identifying the active concentrations, evaluated their impact upon the growth and metabolic activity (organic acid production and sugar consumption) of five potential probiotic microorganisms. Results showed that the extract, at a concentration that inhibited L. monocytogenes, B. cereus, E. coli and S. enteritidis (1000 μg mL−1), had no inhibitory effect on the growth of the potential probiotic stains used. However, the results demonstrated, for the first time, that the extract had a significant impact on the metabolic activity of all probiotic strains, resulting in higher amounts of organic acid production (acetic, citric and lactic acids) and an earlier production of propionic acid.info:eu-repo/semantics/publishedVersio

Chitosan nanoparticles production: optimization of physical parameters, biochemical characterization, and stability upon storage

Ionic gelation is among the simplest processes for the development of chitosan nanoparticles reported so far in the literature. Its one‑shot synthesis process in conjunction with the mild reaction conditions required are among the main causes for its success. In this work, we sought to optimize a set of physical parameters associated with the ionic gelation process at two different pH values. Following that, the NPs’ freeze‑drying and long‑term storage stability were assayed, and their biocompatibility with HaCat cells was evaluated. The results show that NPs were more homogenously produced at pH 5, and that at this pH value, it was possible to obtain a set of optimum production conditions. Furthermore, of the assayed parameters, TPP addition time and overall reaction time were the parameters which had a significant impact on the produced NPs. Nanoparticle freeze‑drying led to particle aggregation, and, of the cryoprotectants, assayed mannitol at 10% (w/v) presented the best performance, as the NPs were stable to freeze‑drying and maintained their size and charge in the long‑term stability assay. Lastly, the chitosan NPs presented no toxicity towards the HaCat cell line.info:eu-repo/semantics/publishedVersio

Antiadhesive and antibiofilm effect of malvidin-3-glucoside and malvidin-3-glucoside/neochlorogenic acid mixtures upon staphylococcus

Several reports on the biological activity of anthocyanin-rich extracts have been made. However, despite the association of said activity with their anthocyanin content, to the best of our knowledge, there are no previous works regarding the antimicrobial, antibiofilm and/or antiadhesive properties of anthocyanins alone. Therefore, the present work aimed to determine the effects of malvidin-3-glucoside, a major component of a previously reported extract, and the impact of its association with neochlorogenic acid (the only non-anthocyanin phenolic present in said extract), upon several Staphylococcus strains with varying resistance profiles. Results show that, while malvidin- 3-glucoside and malvidin-3-glucoside/neochlorogenic acid mixtures were unable to considerably inhibit bacterial growth after 24 h, they still possessed an interesting antibiofilm activity (with reductions of biofilm entrapped cells up to 2.5 log cycles, metabolic inhibition rates up to 81% and up to 51% of biomass inhibition). When considering the bacteria’s capacity to adhere to plain polystyrene surfaces, the inhibition ranges were considerably lower (21% maximum value). However, when considering polystyrene surfaces coated with plasmatic proteins this value was considerably higher (45% for adhesion in the presence of extract and 39% for adhesion after the surface was exposed to extract). Overall, the studied anthocyanins showed potential as future alternatives to traditional antimicrobials in adhesion and biofilm formation prevention.info:eu-repo/semantics/publishedVersio

Frequência de isolados clínicos de escherichia coli produtores de β-lactamases de largo espectro

Foi objectivo deste estudo determinar a frequência de isolados de E. coli produtores de β-lactamases de largo espectro (ESBLs) tanto em infecções nosocomiais como da comunidade, e avaliar a susceptibilidade aos antibióticos entre as estirpes produtoras e não produtoras de ESBLs. Dos 131 isolados investigados apenas 9 (6.8%) se enquadraram nos critérios definidos pelo CLSI para screening de ESBLs, e a sua presença foi confirmada por Etest ESBL. Estes isolados provieram maioritariamente de infecções da comunidade em doentes com idade avançada e história de hospitalização prévia. A maioria (66.6%) mostrou resistência simultânea aos β-lactâmicos estudados, às quinolonas e aos aminoglicosídeos.It was the purpose of this study to determine the frequency of extended­spectrum β­Lactamases (ESBLs) producing isolates in E. coli, from hospital acquired and community infections, and to evaluate antibiotic susceptibility between ESBL producing and non­producing strains. Of 131 isolates investigated only 9 (6.8%) fulfil CLSI screening criteria for ESBL, and its production was confirmed by ESBL Etest. This strains were mainly recovered form community infections in old aged patients, with an history of previous hospitalisation. The majority (66.6%) showed simultaneous resistance to the studied β­lactams, the quinolones and aminoglycosides

Understanding the anti-obesity potential of an avocado oil-rich cheese through an in vitro co-culture intestine cell model

Nowadays, with consumers’ requirements shifting towards more natural solutions and the advent of nutraceutical-based approaches, new alternatives for obesity management are being developed. This work aimed to show, for the first time, the potential of avocado oil-fortified cheese as a viable foodstuff for obesity management through complex in vitro cellular models. The results showed that oleic and palmitic acids’ permeability through the Caco-2/HT29-MTX membrane peaked at the 2h mark, with the highest apparent permeability being registered for oleic acid (0.14 cm/s). Additionally, the permeated compounds were capable of modulating the metabolism of adipocytes present in the basal compartment, significantly reducing adipokine (leptin) and cytokine (MPC-1, IL-10, and TNF-α) production. The permeates (containing 3.30 µg/mL of palmitic acid and 2.16 µg/mL of oleic acid) also presented an overall anti-inflammatory activity upon Raw 264.7 macrophages, reducing IL-6 and TNF-α secretion. Despite in vivo assays being required, the data showed the potential of a functional dairy product as a valid food matrix to aid in obesity management.info:eu-repo/semantics/publishedVersio

Chitosan nanoparticles as bioactive vehicles for textile dyeing: a proof of concept

In recent years bioactive textiles have risen to the forefront of consumers perception due to their potential protection against virus, fungi and bacteria. However, traditional textile staining is an eco-damaging process that and current methods of textile functionalization are expensive, complicated and with great environmental impact. With that in mind, this work sought to show a possible solution for this problematic through the usage of a novel one step textile dyeing and functionalization method based upon nanoencapsulated textile dyes (NTDs). To do so navy blue everzol NTDs were produced with chitosan, cotton dyed, characterized through FTIR and SEM and biological potential evaluated through biocompatibility screening and antimicrobial activity against skin pathogens. The data obtained showed that NTDs effectively dyed the target textile through a coating of the cotton fibre and that NTDs formed hydrogen bonds with the cellulose fibre via electrostatic interactions of the chitosan amino groups with cotton sulphate groups. From a biocompatibility perspective NTDs dyed cotton had no deleterious effects upon a skin cell line, as it promoted cellular metabolism of HaCat cells, while traditionally died cotton reduced it by 10%. Last but not least, NTDs dyed cotton showed significant antimicrobial activity as it reduced viable counts of MRSA, MSSA and A. baumannii between 1 and 2 log of CFU while traditional dyed cotton had no antimicrobial activity. Considering these results the novel method proposed shows is a viable and ecological alternative for the development of antimicrobial textiles with potential biomedical applications.info:eu-repo/semantics/publishedVersio

Insights into the biocompatibility and biological potential of a chitosan nanoencapsulated textile dye

Traditionally synthetic textile dyes are hazardous and toxic compounds devoid of any biological activity. As nanoencapsulation of yellow everzol textile dye with chitosan has been shown to produce biocompatible nanoparticles which were still capable of dyeing textiles, this work aims to further characterize the biocompatibility of yellow everzol nanoparticles (NPs) and to ascertain if the produced nanoencapsulated dyes possess any biological activity against various skin pathogens in vitro assays and in a cell infection model. The results showed that the NPs had no deleterious effects on the HaCat cells’ metabolism and cell wall, contrary to the high toxicity of the dye. The biological activity evaluation showed that NPs had a significant antimicrobial activity, with low MICs (0.5–2 mg/mL) and MBCs (1–3 mg/mL) being registered. Additionally, NPs inhibited biofilm formation of all tested microorganisms (inhibitions between 30 and 87%) and biofilm quorum sensing. Lastly, the dye NPs were effective in managing MRSA infection of HaCat cells as they significantly reduced intracellular and extracellular bacterial counts.info:eu-repo/semantics/publishedVersio

Formulações de entrega de peptídeos antimicrobianos para a cicatrização de feridas

National Patent (INPI)A presente divulgação diz respeito a formulações de entrega de peptídeos antimicrobianos para a cicatrização de feridas, em particular diz respeito a uma composição que compreende pelo menos um polímero, pelo menos um péptido antimicrobiano compreendendo pelo menos uma sequência 95% idêntica à sequência seq. id 1, em particular idêntica à seq id 1. e com uma quantidade terapeuticamente eficaz de todos componentes anteriores.info:eu-repo/semantics/publishedVersio

Laccase immobilization on enzymatically functionalized polyamide 6,6 fibres

Polyamide matrices, such as membranes, gels and non-wovens, have been applied as supports for enzyme immobilization, although in literature the enzyme immobilization on woven nylon matrices is rarely reported. In this work, a protocol for a Trametes hirsuta laccase immobilization using woven polyamide 6,6 (nylon) was developed. A 24 full factorial design was used to study the influence of pH, spacer (1,6-hexanediamine), enzyme and crosslinker concentration on the efficiency of immobilization. The factors enzyme dosage and spacer seem to have played a critical role in the immobilization of laccase onto nylon support. Under optimized working conditions (29 U mL−1 of laccase, 10% of glutaraldehyde, pH = 5.5, with the presence of the spacer), the half-life time attained was about 78 h (18% higher than that of free enzyme), the protein retention was 30% and the immobilization yield was 2%. The immobilized laccase has potential for application in the continuous decolourization of textile effluents, where it can be applied into a membrane reactor