1,720,992 research outputs found
4-Methylcoumarins as antioxidants: Scavenging of peroxyl radicals and inhibition of human low-density lipoprotein oxidation
No full textThe antioxidant activity of eight synthetic 4-methylcoumarins was systematically studied. The antioxidant capacity was measured using: (i) a competition kinetic test, to measure the relative capacity to quench peroxyl radical; (ii) the in vitro oxidative modification of human low-density lipoprotein, initiated by AAPH or catalyzed by copper. In both models, the ortho-OH substitutes were found to be better antioxidant than the meta one. The most efficient antioxidant was the 7,8-dihydroxy-4-methylcoumarin and the corresponding diacetoxy-substituted was unexpectedly a good antioxidant. Finally, the presence of an ethoxycarbonylethyl substituent at the C-3 position increased the antioxidant capacity of both 7,8-dihydroxy-4-methylcoumarin and 7,8-diacetoxy-4-methylcoumarin. (C) 2010 Elsevier Masson SAS. All rights reserved
Metabolic transformation of apple polyphenols in human body
Full text linkRationale: Fruit and vegetables are claimed to have beneficial effect on human health mostly due to their high polyphenol (PP)
content. (1) Regular consumption is protective against age related diseases and different forms of cancer (2). As PP are largely metabolized both by the human organism and gut microbiota, identification of the forms of metabolites and the kinetics of their appearance into the circulation is essential for understanding their possible bioactivity in humans.
Methods: In order to evaluate absorption and transformation of apple polyphenols, a human single-dose crossover controlled blind
experiment was designed. In 2 different sessions 12 subjects were supplemented with apple juice (1 g/l total PF) or polyphenol
enriched apple juice (4 g/l total PF). Urine and plasma samples were collected at different time points and analyzed using an
untargeted metabolomics approach.
Results: Scarcely metabolized polyphenols were recognized as potential biomarkers. These compounds showed two different kinetic
patterns. Epicatechin methyl sulfate, ferulic acid sulfate and phloretin glucuronide reached their maximal concentration 1 hour after apple juice supplementation. While, the methyl, sulfate and glucuronide conjugates of valerolactons had their peak concentration 5 hours after the supplementation. The concentration of the majority of the biomarkers showed an increase four times greater in high PP
diet than in low.
Conclusion: Untargeted metabolomics allowed identification of biomarkers of apple consumption and demonstrated that an increase
in polyphenol intake corresponds to an increase of circulating metabolites within the limits of ‘normal’ consumption. Thus, if the beneficial effects of these compounds are confirmed, it might prove beneficial to increase their plasma concentration by increasing their intake or choosing polyphenols richer food
Glicosinolates in food
No full textGlucosinolates are secondary plant metabolites that have attracted researcher’s
attention due to their potential chemopreventive activity. More than 120 different
glucosinolates have been identified in plants, and several of these compounds
have been studied for the potential anti-cancerogenic effect of their metabolic
breakdown products (mainly ITCs).
Glucosinolates are peculiar of vegetables belonging to Brassicaceae family but
are present also in few other species (capers, papaya, and moringa) used for
human consumption. The type and concentration of glucosinolates in food are
highly variable depending on several factors, such as genetics, cultivation site,
cultivar, growth conditions, developmental stage, plant tissue, post-harvest handling,
and food preparation methods. As types and concentration are also the
main determinant of their biological activities, estimates of their content in food
are essential tool to understand if a certain diet is adequate to deliver qualitatively
and quantitatively appropriate glucosinolates and ITCs.
The aim of this chapter is to describe qualitative and quantitative glucosinolate
distribution among commonly eaten food, as well as the effect of the post-harvest
handling on the glucosinolate food content
Effects of olive polyphenols administration on nerve growth factor and brain-derived neurotrophic factor in the mouse brain
No full textObjective: Polyphenols are chemicals derived from plants known to possess antioxidant and anti-inflammatory properties. High intake of fruit and vegetables is believed to be beneficial to human health. Various studies have suggested that dietary polyphenols may protect against cancer and cardiometabolic and neurodegenerative diseases. Nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are neurotrophins that play key roles in brain cell development, growth, and survival. The aim of this study was to investigate whether or not administration of olive (Olea europaea L.) polyphenols could have an effect on NGF and BDNF content and the expression of their receptors, TrkA and TrkB, respectively, in the mouse brain. Methods: NGF and BDNF were measured by enzyme-linked immunosorbent assay. TrkA and TrkB were measured by Western blotting. Results: We found NGF and BDNF elevation in the hippocampus and olfactory bulbs and a decrease in the frontal cortex and striatum. These data were associated with potentiated expression of TrkA and TrkB in the hippocampus and olfactory bulbs but no differences between groups in the striatum and frontal cortex. Polyphenols did not affect some behavioral mouse parameters associated with stressing situations. Conclusions: Altogether, this study shows that olive polyphenols in the mouse may increase the levels of NGF and BDNF in crucial areas of the limbic system and olfactory bulbs, which play a key role in learning and memory processes and in the proliferation and migration of endogenous progenitor cells present in the rodent brain. © 2013 Elsevier Inc
SCREENING GROWTH CONDITIONS TO INCREASE ANTHOCYANINS AND GLUCOSINOLATES CONTENT IN BROCCOLI SPROUTS
No full textBroccoli (Brassicaceae) are an excellent dietary source of micronutrients (vitamins and minerals) and health-promoting phytochemicals (glucosinolates and phenolic compounds). Glucosinolates are a class of organic compounds derived from glucose and different aminoacids, and characterized by the high number of different side chains. Anthocyanins represent the largest group of natural, water-soluble plant pigments, and approximately 400 anthocyanins have been determined. Glucosinolates and anthocyanins protects plants against various biotic and abiotic stresses and possess antioxidant and antinflammatory activity in humans. In addition, glucosinolates have gained much attention due to the anticarcinogenic activity of isothiocyanates, their major hydrolysis products, molecules able to induce phase 2 detoxication enzymes and protect animals against chemically induced cancer (Zhang, 2012). Young broccoli plant are an especially good source of glucosinolates and anthocyanins and several studies report that growth and environmental conditions could affect the profiles of these secondary plant metabolites (Perez-Balibrea et al., 2008).
We previously developed a rapid and sensitive LC-MS (MRM) method for direct and simultaneous quantification of 14 glucosinolates in broccoli sprouts. In this study, the effect of different abiotic stresses and hormones involved in plant defence responses of the accumulation of glucosinolates and anthocyanins in broccoli sprouts was investigated. Quantitative results show that all treatments modify glucosinolates and anthocyanins profile. In particular, light grown broccoli sprouts treated with sucrose show glucosinolates and anthocyanins levels double than control. This work was ,supported by Italian Ministry of Agriculture, Food & Forestry (MiPAAF) grant "NUTRIGEA" (DM 30281 23112/2009)
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
One site on the apoB-100 specifically binds 17-beta-estradiol and regulates the overall structure of LDL.
No full textThe major protein component (apoB-100) of low-density lipoprotein (LDL) is known as a multipotential molecule the several functional regions of which can all be affected by key structural modifications driven by specific domains. Based on our previous report on structural and conformational modifications of apoB-100 in the presence of 17-beta-estradiol (E2), we characterized the interaction between E2 and the apoB-100 and further explored the induced alterations in terms of the structural arrangement of the whole LDL particle. We report evidence for the existence on apoB-100 of a single specific and saturable binding site for E2, the occupancy of which modifies the overall structure of the protein, inducing an increase in the alpha-helix fraction. As a consequence, the structure of the LDL particle is deeply perturbed, with a change in the arrangement of both the outer shell and lipid core and an overall volume shrinkage. The evidence of a regulation of apoB-100 structure by a physiological ligand opens new perspectives in the study of the biological addressing of the LDL particle and suggests a novel rationale in the search for mechanisms underlying the beneficial role of E2 in decreasing the risk of early lesions in atherosclerosis
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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