1,721,056 research outputs found
Oxidative Stress, Antioxidant Capabilities, and Bioavailability: Ellagic Acid or Urolithins?
No full textOxidative stress (OS), triggered by overproduction of reactive oxygen and nitrogen
species, is the main mechanism responsible for several human diseases. The available one-target
drugs often face such illnesses, by softening symptoms without eradicating the cause. Differently,
natural polyphenols from fruits and vegetables possess multi-target abilities for counteracting OS,
thus representing promising therapeutic alternatives and adjuvants. Although in several in vitro
experiments, ellagitannins (ETs), ellagic acid (EA), and its metabolites urolithins (UROs) have
shown similar great potential for the treatment of OS-mediated human diseases, only UROs have
demonstrated in vivo the ability to reach tissues to a greater extent, thus appearing as the main
molecules responsible for beneficial activities. Unfortunately, UROs production depends on individual
metabotypes, and the consequent extreme variability limits their potentiality as novel therapeutics, as
well as dietary assumption of EA, EA-enriched functional foods, and food supplements. This review
focuses on the pathophysiology of OS; on EA and UROs chemical features and on the mechanisms of
their antioxidant activity. A discussion on the clinical applicability of the debated UROs in place of
EA and on the effectiveness of EA-enriched products is also includedOxidative stress (OS), triggered by overproduction of reactive oxygen and nitrogen species, is the main mechanism responsible for several human diseases. The available one‐target drugs often face such illnesses, by softening symptoms without eradicating the cause. Differently, natural polyphenols from fruits and vegetables possess multi‐target abilities for counteracting OS, thus representing promising therapeutic alternatives and adjuvants. Although in several in vitro experiments, ellagitannins (ETs), ellagic acid (EA), and its metabolites urolithins (UROs) have shown similar great potential for the treatment of OS‐mediated human diseases, only UROs have demonstrated in vivo the ability to reach tissues to a greater extent, thus appearing as the main molecules responsible for beneficial activities. Unfortunately, UROs production depends on individual metabotypes, and the consequent extreme variability limits their potentiality as novel therapeutics, as well as dietary assumption of EA, EA‐enriched functional foods, and food supplements. This review focuses on the pathophysiology of OS; on EA and UROs chemical features and on the mechanisms of their antioxidant activity. A discussion on the clinical applicability of the debated UROs in place of EA and on the effectiveness of EA‐enriched products is also included
Nanotechnology application in food packaging: a plethora of opportunities versus pending risks assessment and public concerns
No full textEnvironmental factors, oxidation and microorganisms contamination, are the major causes for food spoilage, which leads
to sensory features alteration, loss of quality, production of harmful chemicals and growth of foodborne pathogens capable
to cause severe illness. Synthetic preservatives, traditional conserving methods and food packaging (FP), although
effective in counteracting food spoilage, do not allow the real-time monitoring of food quality during storage and
transportation and assent a relatively short shelf life. In addition, FP may protect food by the spoilage caused by external
contaminations, but is ineffective against foodborne microorganisms. FP preservative functionalities could be improved
adding edible natural antioxidants and antimicrobials, but such chemicals are easily degradable. Nowadays, thanks to
nanotechnology techniques, it is possible to improve the FP performances, formulating and inserting more stable
antioxidant/antimicrobial ingredients, improving mechanical properties and introducing intelligent functions. The stateof-
the-art in the field of nanomaterial-based improved FP, the advantages that might derive from their extensive
introduction on the market and the main concerns associated to the possible migration and toxicity of nanomaterials,
frequently neglected in existing reviews, have been herein discussed
Paradox Role of Oxidative Stress in Cancer: State of the Art
No full textThe modulation of oxidative stress is essential for the maintenance of redox homeostasis in healthy and cancer cells [...
MiRNA Regulation of Glutathione Homeostasis in Cancer Initiation, Progression and Therapy Resistance
No full textGlutathione (GSH) is the most abundant antioxidant that contributes to regulating the cellular production of Reactive Oxygen Species (ROS) which, maintained at physiological levels, can exert a function of second messengers in living organisms. In fact, it has been demonstrated that moderate amounts of ROS can activate the signaling pathways involved in cell growth and proliferation, while high levels of ROS induce DNA damage leading to cancer development. Therefore, GSH is a crucial player in the maintenance of redox homeostasis and its metabolism has a role in tumor initiation, progression and therapy resistance. Our recent studies have demonstrated that neuroblastoma cells resistant to etoposide, a common chemotherapeutic drug, show a partial monoallelic deletion of the locus coding for miRNA 15a and 16-1. leading to a loss of these miRNAs and the activation of GSH-dependent responses. Therefore, the aim of this review is to highlight the role of specific miRNAs in the modulation of intracellular GSH levels in order to take into consideration the use of modulators of miRNA expression as a useful strategy to better sensitize tumors to current therapies
Development of a Fast, Low‐Cost, Conservative and Ecological Method for Quantifying Gallic Acid in Polymeric Formulations by FTIR Spectroscopy in Solution
No full textThe beneficial polyphenol gallic acid (GA) is often loaded in
polymeric systems to improve its poor bioavailability and low
stability, therefore quantifying its concentration is mandatory.
Chromatography is expensive, time long and non-ecological;
partial least square-based near-infrared technique requires
interpretative chemometrics tools; ultraviolet/visible (UV-Vis)
method is non-specific and destructive. Herein, using Fourier
transform infrared (FTIR) spectroscopy, a fast, low-cost, ecological
and conservative method for quantifying GA in polymer
matrices was developed, by acquiring spectra of GA solutions
at different GA concentrations (CGAs). Selected spectral data
and CGAs were used to build a linear regression model by least
squares approach, subsequently validated adopting samples of
three different GA polymer formulations, as validation sets. Test
samples were analyzed by FTIR technique and the model was
used to determine CGAs, which were predicted with minimal
absolute errors (0.01-0.03). This method is robust and extendable
also to other precious polymeric matrices or valuable
substances
Polyester-Based Dendrimer Nanoparticles Combined with Etoposide Have an Improved Cytotoxic and Pro-Oxidant Effect on Human Neuroblastoma Cells
No full textEtoposide (ETO) is a cytotoxic drug that exerts its effect by increasing reactive oxygen species (ROS) production. Although ETO is widely used, fast metabolism, poor solubility, systemic toxicity, and multi-drug resistance induction all limit its administration dosage and its therapeutic efficiency. In order to address these issues, a biodegradable dendrimer was prepared for entrapping and protecting ETO and for enhancing its solubility and effectiveness. The achieved dendrimer complex with ETO (CPX 5) showed the typical properties of a well-functioning delivery system, i.e., nanospherical morphology (70 nm), optimal Z-potential (−45 mV), good drug loading (37%), very satisfying entrapment efficiency (53%), and a remarkably improved solubility in biocompatible solvents. In regards to its cytotoxic activity, CPX 5 was tested on neuroblastoma (NB) cells with very promising results. In fact, the dendrimer scaffold and ETO are able to exert per se a cytotoxic and pro-oxidant activity on human NB cells. When CPX 5 is combined with ETO, it shows a synergistic action, slowly releasing the drug over time and significantly improving and protracting bioactivity. On the basis of these findings, the prepared ETO reservoir represents a novel biodegradable and promising device for the delivery of ETO into NB cells
Editorial: Redox metabolism: a double edge sword sustaining the adaptive resistance to therapy in cancer
Full text linkNo abstract available
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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