305,323 research outputs found
Biological activity of ethanol extract from leaves of Rosmarinus eriocalyx
No full textAging or senescence is a complex and inevitable process, which is not only attributed to individual genetic variation but also to external factors such as environmental conditions, nutrition, alcohol, and diseases [1]. The most widely accepted theory, that have been proposed to explain aging, is the free radical theory [2]. Aging and related diseases result from accumulated oxidative damage to cell constituents and tissues caused by excessive exposure to free radicals. Antioxidants, which mediate the imbalance between intracellular antioxidant defenses and oxidative damage by reducing the reactive oxygen species (ROS) levels, are believe to be able to reduce stress-induced premature senescence or slow down replicative senescence [3].
Rosmarinus eriocalyx (Jord. & Fourr.) is an aromatic evergreen bush belonging to Lamiaceae family and endemic to Algeria, Morocco and Spain, where it is used as a condiment to flavor soup and meat and as a traditional remedy [4]. The plant volatile fraction is characterized by the monoterpene ketone camphor, whereas its ethanolic extracts are rich sources of phenolic acids and diterpenes such as rosmarinic acid, carnosic acid and carnosol that are the main responsible for the noteworthy antioxidant activity [5].
In this setting, we aimed to evaluate R. eriocalyx biological activity in order to propose the plant as an anti-aging agent. For this purpose, we determined the cytotoxic activity of polar extracts obtained from leaves, flowers, and stems of R. eriocalyx on human fibroblast and human tumor cell lines (A375, MDA-MB 231, and T98G) by MTT assay [6]. Results showed that the ethanolic extract of leaves resulted the most active against A375 human melanoma cell line (IC50 value of 17.8 μg/ml). The total phenolic content values reported for R. eriocalyx ethanolic and aqueous extracts showed slight differences and free radical scavenging activity was stronger for ethanolic extracts than aqueous ones. On this basis, we selected the R. eriocalyx ethanolic extract to determine the antioxidant activity on human fibroblast by measuring its ability to prevent oxidation in cells using a ROS fluorescent probe (DCFH-DA) [7]. Results showed a remarkable activity in preventing oxidation of cells induced by 2.2’-azobis -2-amidinopropane (ABAP). Afterwards, we tested the same extract on the H2O2-induced premature senescence in young fibroblast cells where -galactosidase (SA--gal) activity was used to measure cell senescence [8]. Preliminary data showed a reduction of H2O2 stress-induced premature senescence indicating the potential of R. eriocalyx leaf extract to be formulated as an anti-aging agent.
References
[1] N. Getoff. Anti-aging and aging factors in life. The role of free radicals. Radiat. Phys. Chem. 2007, 76,1577-1586.
[2] D. Harman. Aging: a theory based on free radical and radiation chemistry. J. Gerontol. 1956, 11, 298-300.
[3] D. Fusco, G. Colloca, M.R. Lo Monaco, M. Cesari. Effects of antioxidant supplementation on the aging process. Clin. Interv. Aging. 2007, 2, 377-387.
[4] M.S. Bendeddouche, H. Benhassaini, Z. Hazem, A. Romane. Essential oil analysis and antibacterial activity of Rosmarinus tournefortii from Algeria. Nat. Prod. Commun. 2011, 6, 1511-1514.
[5] H. Bendif, M. Boudjeniba, M. Djamel Miara, L. Biqiku, M. Bramucci, G. Caprioli, G. Lupidi, L. Quassinti, G. Sagratini, L.A. Vitali, S. Vittori, F. Maggi. Rosmarinus eriocalyx: An alternative to Rosmarinus officinalis as a source of antioxidant compounds. Food Chem. 2017, 218, 78-88.
[6] L. Quassinti, G. Lupidi, F. Maggi, F. Papa, S. Vittori, A. Bianco, M. Bramucci . Antioxidant and antiproliferative activity of Hypericum hircinum L. subsp. majus (Aiton) N. Robson essential oil. Nat. Prod. Res. 2013, 27, 862-868.
[7] K.L. Wolfe, R.H. Liu. Cellular antioxidant activity (CAA) assay for assessing antioxidants, foods, and dietary supplements. J. Agric. Food Chem. 2007, 55, 8896-8907.
[8] D.J. Kurz, S. Decary, Y. Hong, J.D. Erusalimsky. Senescence-associated -galactosidase reflects an increase in lysosomal mass during replicative ageing of human endothelial cells. J. Cell Sci. 2000, 113, 3613–3622
The governance of offshoring and its effects at home: The role of codetermination in the international organization of German firms
No full textThis paper focuses on the links between labor market institutions and offshoring, with specific reference to the role of codetermination in shaping the international operations of German firms. We use case studies to illustrate how works councils deal with three important aspects of offshoring processes: the timeliness of information they receive from the management, the negotiation of compensation mechanisms and the design of alternative strategies. While we found no evidence of works councils impeding offshoring, there are elements to suggest that they may influence the way such decisions are taken, and moderate their effects on employment in the home country
The governance of offshoring and its effects at home.The role of codetermination in the international organization of German firms
No full textThis paper focuses on the links between labor market institutions and
offshoring, with specific reference to the role of codetermination in shaping the
international operations of German firms. We use case studies to illustrate how
works councils deal with three important aspects of offshoring processes: the
timeliness of information they receive from the management, the negotiation of
compensation mechanisms, and the design of alternative strategies. While we found
no evidence of works councils impeding offshoring, there are elements to suggest
that they may influence the way such decisions are taken and moderate their effects
on employment in the home country
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Determinazione di cortisolo e cortisone in saliva mediante HPLC-UV-SPE
No full textIl cortisolo ((11β)-11,17,21-triidrossipregn-4-ene-3,20-dione), noto anche come idrocortisone, è il più importante glucocorticoide nell’uomo ed è sintetizzato sotto l’influenza diretta dell’ormone adrenocorticotropo (ACTH). Nell’uomo, in assenza di stress, vengono secreti secondo un ritmo circadiano dagli 8 ai 25 μg di cortisolo nell’arco delle 24 ore e si ha la massima produzione tra le 8:00 e le 10:00 del mattino, quando l’asse ipotalamo-ipofisi-surrene è in piena attività. Il cortisone (17,21-diidrossipregn-4-en-3,11,20-trione) è la forma inattiva del cortisolo e si differenzia da esso per la presenza in posizione 11 di un gruppo chetonico al posto dell’ossidrile. La trasformazione bidirezionale del cortisolo a cortisone avviene per azione dell’enzima 11β-idrossisterido-deidrogenasi (11β-HSD) che ne modula anche la bioattività regolandone l’azione nei tessuti bersaglio (tra cui le ghiandole salivari) con un meccanismo prerecettoriale. Recentemente, la saliva è sempre più considerata una matrice che può fornire utili informazioni sul funzionamento di vari organi all'interno del corpo; in particolare, il cortisolo salivare ha ricevuto molta attenzione come biomarker di stress psicologico e i suoi livelli possono essere correlati a malattie mentali e/o fisiche. Pertanto l’analisi dei campioni di saliva è utile per confermare i ritmi diurni di cortisolo e cortisone nelle condizioni basali. Lo scopo di questo studio è lo sviluppo di un metodo cromatgrafico a fase inversa per l’analisi dei due steroidi in saliva. A tal fine è stato utilizzato un sistema HPLC a fase inversa accoppiato ad un detector UV. Inoltre, è stata sviluppata una procedura di estrazione in fase solida (SPE) per la purificazione dei campioni salivari. Sono stati ottenuti buoni risultati in termini di resa di estrazione, linearità e precisione. I risultati preliminari su campioni di volontari sani sembrano promettenti
Small acidic peptides are bound to E. coli DNA.
No full textLow molecular weight peptides have been isolated by alkali extraction from deproteinized DNA of E. coli cells grown in the presence of radioactive glutamic acid or orthophosphate. The labeled peptides, purified by gel filtration chromatography on Sephadex G25 and G10, contain prevailingly glutamic acid, aspartic acid, glycine, serine and alanine. Electrophoretic studies at different pH show that some peptide fractions contain a phosphoric residue. The N-terminus of the phosphorylated peptides is apparently blocked and they were able to bind to DNA in the presence of Mg2+ ions. Moreover the acidic peptides extracted from E. coli DNA show a sharp activity in the control of lambda phage DNA transcription 'in vitro'
Relationship between the -374 T/A RAGE gene polymorphism and severity of coronary atherosclerosis
No full textPurification of swine serum angiotensin converting enzyme with high recovery of activity using lisinopril coupled to epoxy-activated sepharose 6B.
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