Time filter

Source Type

Sampaio A.C.,University of Trás os Montes e Alto Douro | Sampaio A.C.,Center for Research and Technology of Agro Environmental and Biological science | Mendes R.J.,University of Trás os Montes e Alto Douro | Castro P.G.,University of Trás os Montes e Alto Douro | And 2 more authors.
Ecotoxicology and Environmental Safety | Year: 2017

Solid lipid nanoparticles (SLNs) are used as carriers for drug delivery, and are high biocompatible and designed to endure in the host organism. Despite its current industrial production is low, many of these substances are available on the market, and much more are in the production pipeline. As a result, many of them will end in aquatic systems raising the question whether they can pose a risk to aquatic biota and the associated ecological processes. Microbial decomposers of plant litter, play a key role in forested streams being responsible for the energy flow between terrestrial and aquatic environments. Here, we investigated the effects of SLNs on alder leaf litter decomposition by aquatic microbes. Alder leaves were immersed in a stream of Northeast Portugal to allow microbial colonization before being exposed in microcosms of two types of SLNs at two concentrations for 42 days. Results showed that rates of leaf decomposition decreased with exposure to SLNs. Bacterial biomass was not inhibited by SLNs, and cultivable fungi densities remained constant (SLN-A) or increased (SLN-C) compared with control microcosms. The type and concentration of SLNs influenced differently the leaf colonization by fungi as well as fungal sporulation rate. These effects were accompanied by changes in the community extraenzymatic profile: the activities of alkaline phosphatase, acidic phosphatase, Naphthol-AS-BI-phosphohydrolase (P cycle) and lipases increased in the SLNs microcosms. This study provided the first evidence of the adverse effects of the release of SLNs to streams on leaf litter decomposition. Those effects seem to depend on the composition and concentration of SLNs, as well on the microbial target group, or enzyme. Thus, prior to massive industrial production of these nanomaterials, some measures should be taken to avoid environmental impact affecting the microbial communities responsible for detritus decomposition. © 2016 Elsevier Inc.


Soares J.P.,University of Trás os Montes e Alto Douro | Silva A.M.,Center for Research and Technology of Agro Environmental and Biological science | Peixoto F.,Center for Research and Technology of Agro Environmental and Biological science | Gaivao I.,Animal and Veterinary Research Center | Mota M.P.,University of Trás os Montes e Alto Douro
Age | Year: 2015

Regular physical exercise has been shown to be one of the most important lifestyle influences on improving functional performance, decreasing morbidity and all causes of mortality among older people. However, it is known that acute physical exercise may induce an increase in oxidative stress and oxidative damage in several structures, including DNA. Considering this, the purpose of this study was to identify the effects of 16 weeks of combined physical exercise in DNA damage and repair capacity in lymphocytes. In addition, we aimed to investigate the role of oxidative stress involved in those changes. Fifty-seven healthy men (40 to 74 years) were enrolled in this study. The sample was divided into two groups: the experimental group (EG), composed of 31 individuals, submitted to 16 weeks of combined physical exercise training; and the control group (CG), composed of 26 individuals, who did not undergo any specifically orientated physical activity. We observed an improvement of overall physical performance in the EG, after the physical exercise training. A significant decrease in DNA strand breaks and FPG-sensitive sites was found after the physical exercise training, with no significant changes in 8-oxoguanine DNA glycosylase enzyme activity. An increase was observed in antioxidant activity, and a decrease was found in lipid peroxidation levels after physical exercise training. These results suggest that physical exercise training induces protective effects against DNA damage in lymphocytes possibly related to the increase in antioxidant capacity. © 2015, American Aging Association.


Soares J.P.,Research Center in Sports science | Silva A.M.,Center for Research and Technology of Agro Environmental and Biological science | Fonseca S.,Research Center in Sports science | Peixoto F.,Center for Research and Technology of Agro Environmental and Biological science | And 2 more authors.
Experimental Gerontology | Year: 2015

Age-related DNA damage has been regarded as one of the possible explanations of aging, and these age-related changes have been associated with lifestyle variables. Considering this, the purpose of this study was to investigate how age and lifestyle may affect DNA damage, DNA repair capacity and endogenous biomarkers of oxidative stress. Sixty-one healthy men (40 to 89. yrs) were enrolled in this study. The results showed that DNA strand breaks (DNA SBs) and DNA repair capacity were greater in the older group (> = 65. yrs) compared to the younger group (< 65 yrs) (p < 0.05). FPG-sensitive sites, total antioxidant capacity and lipid peroxidation (MDA) were not statistically different between groups. The correlation test showed that DNA damage variables were not correlated with any lifestyle variable excepting DNA SBs which was correlated with aerobic capacity (6MWT). DNA SBs and DNA repair were positively correlated with age. The multiple regression analysis revealed that the aerobic capacity (6MWT) and MDA were the predictors for the variation of DNA SBs (41.9%). In conclusion these results suggest that DNA SB damage increases with age but not FPG-sensitive sites. Moreover, base excision repair capacity increases with age without the increase of oxidative damage to DNA. The most predictable variables of DNA SBs were the aerobic capacity and MDA. © 2015 Elsevier Inc.


Vazzana M.,Messina University | Andreani T.,University of Trás os Montes e Alto Douro | Andreani T.,Center for Research and Technology of Agro Environmental and Biological science | Fangueiro J.,University of Coimbra | And 7 more authors.
Biomedicine and Pharmacotherapy | Year: 2015

Tramadol hydrochloride (TrHC) is a synthetic analgesic drug exhibiting opioid and non-opioid properties, acting mainly on the central nervous system. It has been mostly used to treat pain, although its use to treat anxiety and depression has also been documented. These properties arise from the fact that they inhibit serotonin (5-HT) reuptake augmenting 5-HT concentration on the synaptic cleft. Despite this, TrHC has also been described to have several side effects which are mainly due to its fast metabolization and excretion which in turn requires multiple doses per day. To surpass this limitation, new pharmaceutical formulations are being developed intending the protection, target and sustained delivery as well as a reduction on daily dose aiming a reduction on the side effects. In the present work we have revised the efficacy, safety, biological and adverse effects of TrHC, and the added value of developing a novel drug delivery system for topical administration. © 2015 Elsevier Masson SAS.


Fangueiro J.F.,Fernando Pessoa University | Andreani T.,Fernando Pessoa University | Andreani T.,Center for Research and Technology of Agro Environmental and Biological science | Andreani T.,University of Trás os Montes e Alto Douro | And 7 more authors.
International Journal of Pharmaceutics | Year: 2014

In the present study we have developed lipid nanoparticle (LN) dispersions based on a multiple emulsion technique for encapsulation of hydrophilic drugs or/and proteins by a full factorial design. In order to increase ocular retention time and mucoadhesion by electrostatic attraction, a cationic lipid, namely cetyltrimethylammonium bromide (CTAB), was added in the lipid matrix of the optimal LN dispersion obtained from the factorial design. There are a limited number of studies reporting the ideal concentration of cationic agents in LN for drug delivery. This paper suggests that the choice of the concentration of a cationic agent is critical when formulating a safe and stable LN. CTAB was included in the lipid matrix of LN, testing four different concentrations (0.25%, 0.5%, 0.75%, or 1.0%wt) and how composition affects LN behavior regarding physical and chemical parameters, lipid crystallization and polymorphism, and stability of dispersion during storage. In order to develop a safe and compatible system for ocular delivery, CTAB-LN dispersions were exposed to Human retinoblastoma cell line Y-79. The toxicity testing of the CTAB-LN dispersions was a fundamental tool to find the best CTAB concentration for development of these cationic LN, which was found to be 0.5 wt% of CTAB. © 2013 Elsevier B.V. All rights reserved.


Fangueiro J.F.,Fernando Pessoa University | Andreani T.,Fernando Pessoa University | Andreani T.,Center for Research and Technology of Agro Environmental and Biological science | Andreani T.,University of Trás os Montes e Alto Douro | And 5 more authors.
Colloids and Surfaces B: Biointerfaces | Year: 2012

Solid lipid nanoparticles (SLNs) produced from multiple emulsions technology theoretically enclose an inner aqueous compartment suitable for hydrophilic biomolecules. This paper reports a 33 full factorial design study to optimize SLNs formulations for hydrophilic biomolecules. The concentrations of solid lipid, lipophilic and hydrophilic emulsifiers were set as the 3 independent variables. Mean particle size (Z-Ave), polydispersity index (PI) and zeta potential (ZP) were set as the dependent variables. The selected optimized parameters were set as 1.0wt% of solid lipid, 0.25wt% of lipophilic emulsifier and 1.5wt% of hydrophilic emulsifier. The coating of SLNs with sodium alginate was found to improve the ZP of the lipid particles and these results suggest that the ideal concentration was 0.75wt%. The influence of low pH (i.e., about 2-3) in the inner aqueous phase was stronger than higher pH values, contributing for the production of larger droplet sizes. Nevertheless, these systems can be useful for the incorporation of biomolecules requiring a pH ranging between 4 and 10. SLNs based on multiple emulsions technology were found to be a promising approach for the incorporation of several hydrophilic drugs, such as proteins and peptides. © 2012 Elsevier B.V.


Andreani T.,University of Trás os Montes e Alto Douro | Andreani T.,Center for Research and Technology of Agro Environmental and Biological science | Fangueiro J.F.,Center for Research and Technology of Agro Environmental and Biological science | Fangueiro J.F.,University of Coimbra | And 5 more authors.
Current Pharmaceutical Design | Year: 2015

Hydrophilic polymers are the most common group of polymers used in the preparation of modifiedrelease drug delivery systems. This is due to their versatility, low cost, high production yield, as well as easy manufacturing and adequate in vitro/in vivo correlation. In normal physiological conditions, the matrix controls the release of the loaded drug over time through a process of diffusion and/or erosion of the matrix, depending on its physicochemical composition. This is particularly relevant when describing the pharmacokinetic profile of nanosized drug delivery systems (nanoparticles). The use of mathematical models became an important tool to characterize the pharmacokinetics of drugs loaded in nanoparticles to improve the drug bioavailability and to establish bioequivalence. Therefore, the drug release profile can be predicted by a minimum number of experimental studies, since the mathematical equations reveal the dissolution rate of the drug loaded in the hydrophilic matrix. The present paper discusses the use of mathematical models when developing modified-release drug delivery systems of nanometer size composed of hydrophilic polymers. © 2015 Bentham Science Publishers


Fangueiro J.F.,Fernando Pessoa University | Parra A.,University of Barcelona | Silva A.M.,University of Trás os Montes e Alto Douro | Silva A.M.,Center for Research and Technology of Agro Environmental and Biological science | And 5 more authors.
International Journal of Pharmaceutics | Year: 2014

Epigallocatechin gallate (EGCG) is a green tea catechin with potential health benefits, such as anti-oxidant, anti-carcinogenic and anti-inflammatory effects. In general, EGCG is highly susceptible to degradation, therefore presenting stability problems. The present paper was focused on the study of EGCG stability in HEPES (N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid) medium regarding the pH dependency, storage temperature and in the presence of ascorbic acid a reducing agent. The evaluation of EGCG in HEPES buffer has demonstrated that this molecule is not able of maintaining its physicochemical properties and potential beneficial effects, since it is partially or completely degraded, depending on the EGCG concentration. The storage temperature of EGCG most suitable to maintain its structure was shown to be the lower values (4 or -20 °C). The pH 3.5 was able to provide greater stability than pH 7.4. However, the presence of a reducing agent (i.e., ascorbic acid) was shown to provide greater protection against degradation of EGCG. A validation method based on RP-HPLC with UV-vis detection was carried out for two media: water and a biocompatible physiological medium composed of Transcutol®P, ethanol and ascorbic acid. The quantification of EGCG for purposes, using pure EGCG, requires a validated HPLC method which could be possible to apply in pharmacokinetic and pharmacodynamics studies. © 2014 Published by Elsevier B.V.


Severino P.,University of Campinas | Severino P.,Fernando Pessoa University | Andreani T.,Fernando Pessoa University | Andreani T.,University of Trás os Montes e Alto Douro | And 8 more authors.
European Journal of Medicinal Chemistry | Year: 2014

Insulin was used as model protein to developed innovative Solid Lipid Nanoparticles (SLNs) for the delivery of hydrophilic biotech drugs, with potential use in medicinal chemistry. SLNs were prepared by double emulsion with the purpose of promoting stability and enhancing the protein bioavailability. Softisan®100 was selected as solid lipid matrix. The surfactants (Tween®80, Span®80 and Lipoid®S75) and insulin were chosen applying a 22 factorial design with triplicate of central point, evaluating the influence of dependents variables as polydispersity index (PI), mean particle size (z-AVE), zeta potential (ZP) and encapsulation efficiency (EE) by factorial design using the ANOVA test. Therefore, thermodynamic stability, polymorphism and matrix crystallinity were checked by Differential Scanning Calorimetry (DSC) and Wide Angle X-ray Diffraction (WAXD), whereas the effect of toxicity of SLNs was check in HepG2 and Caco-2 cells. Results showed a mean particle size (z-AVE) width between 294.6 nm and 627.0 nm, a PI in the range of 0.425-0.750, ZP about -3 mV, and the EE between 38.39% and 81.20%. After tempering the bulk lipid (mimicking the end process of production), the lipid showed amorphous characteristics, with a melting point of ca. 30 °C. The toxicity of SLNs was evaluated in two distinct cell lines (HEPG-2 and Caco-2), showing to be dependent on the concentration of particles in HEPG-2 cells, while no toxicity in was reported in Caco-2 cells. SLNs were stable for 24 h in in vitro human serum albumin (HSA) solution. The resulting SLNs fabricated by double emulsion may provide a promising approach for administration of protein therapeutics and antigens. © 2014 Published by Elsevier Masson SAS.


Perez-Gregorio M.R.,CSIC - Institute of Advanced Chemistry of Catalonia | Regueiro J.,University of Vigo | Simal-Gandara J.,University of Vigo | Rodrigues A.S.,Polytechnic Institute of Viana do Castelo | And 2 more authors.
Critical Reviews in Food Science and Nutrition | Year: 2014

Flavonoids are a large and diverse group of polyphenolic compounds with antioxidant effects. While the flavonoid content and composition profile clearly reflect the genetic background of the cultivar, environmental conditions and agronomic practices are also determinants for the composition of crops at harvest. Considerable research has been directed toward understanding the nature of polyphenols in different products and the factors influencing their accumulation. This review examines the flavonoids as a class of compounds, the role these compounds play in the plant, their contributions to product quality, and recent research on the impacts of environmental factors and cultural practices on flavonoid content in onions, highlighting how this knowledge may be used to modulate their polyphenolic composition at harvest or during post-harvest handling. © 2014 Copyright Taylor and Francis Group, LLC.

Loading Center for Research and Technology of Agro Environmental and Biological science collaborators
Loading Center for Research and Technology of Agro Environmental and Biological science collaborators