1,720,958 research outputs found
The effect of green (brazilian) propolis on the expression levels of miRNAs related to oxidative stress and inflammation.
No full textCHARACTERIZED PROPOLIS EXTRACTS, OBTAINED WITH STANDARDIZED EXTRACTION METHOD, SHOWN SIMILAR CHEMICAL PROFILE (HPLC-ESI-MSN) AND IN VITRO ANTIBACTERIAL, ANTIOXIDANT AND ANTI-INFLAMMATORY ACTIVITY TROUGH EVALUATION OF EXPRESSION OF miRNAS, mRNAS AND PROTEINS
No full textDespite the great number of investigations, thè common scientific approaches to study biological activities of propolis present some limitations due to thè high naturai variability of propolis and different extraction methods used. Therefore, thè results obtained so far are often not comparable each other and are poorly reproducible. The aim of this work is thè development of a new extraction method to obtain standardized propolis extracts to be studied in vitro for thè determination of anti-inflammatory, antioxidant and antibacterial activities. The standardized extraction method was set and posited as patent (Multi Dynamic Extraction method M.E.D.®) and thè extracts obtained were characterized; they shown similar chemical profiles (HPLC-ESI-MSn) even if formulated differently (dry, glyceric, glycolic, hydroalcoholic and oily extracts)1.
The antioxidant activity of formulated extracts was firstly determined in vitro (TROLOX) and then, to better clarify thè intracellular mechanisms behind thè antioxidant and anti-inflammatory activities, miRNA, mRNA (RT-qPCR) and their protein validated target (ELISA) changes were evaluated2. Propolis M.E.D.® extracts showed similar antioxidant TROLOX values related to thè amount of polyphenols; moreover, they are able to reduce thè oxidative stress and inflammation level in HaCat cells acting on expression levels of mRNAs coding for NFE2L2, GPX2 and TNF-a and NFE2L2 protein2. These results highlight a possible molecular mechanism of action of Propolis M.E.D.® behind thè antioxidant and anti-inflammatory activity. To test antibacterial activity, different propolis M.E.D.® extracts were tested (MIC) against several strains (ATCC, antibiotics resistant and susceptible) and showed comparable MIC values related to thè amount of standardized polyphenols complex
ACTIVITY STUDIES OF CHARACTERIZED, STANDARDIZED AND HIGHLY PURIFIED PROPOLIS EXTRACT
Full text linkPropolis is a resinous substance collected and transformed by honeybees from various plant sources. It is rich in polyphenols compounds that vary depending on geographical and botanical origin. The new patented productive process, called M.E.D.® (Dynamic Multi Extraction), is able to extract the completeness of polyphenolic fractions present that are: phenolic acids, bioflavonoids (aglycons and glycosylated forms) in a specific blend of brown propolis, coming from selected areas. Thanks to M.E.D. ® process it is possible to obtain the first standardized and highly purified polyphenols extract from propolis. The standardization is based on the content of the functional compounds such as total polyphenols in which six of them (Apigenin, Pinocembrine, Pinobanskine, Chrysin, Galangine, Quercetine) represent more than 25%, signifying a quality indicator of extraction method.
The characterization is performed with HPLC-UV-ESI-MS and tandem mass to give us a qualitative and quantitative profile of purified polyphenols extract and its derivatives.
Based on this standardized and purified polyphenols complex, we have been performed in vitro studies to test its antimicrobial activity against a large panel of microorganisms, in particular against Staphylococcus aureus spp. and Staphylococcus aureus Methicillin- Resistant spp; Streptococci spp
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
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
Chemical Composition and Antioxidant Activity of Propolis Prepared in Different Forms and in Different Solvents Useful for Finished Products
Full text linkDifferent products from a unique propolis extract obtained by using various solvents such as hydroalcoholic, glycolic (98% propylene glycol), and glyceric solutions, and oil, as well as in powder form, named ESIT12, were prepared. The molecular composition of the different preparations was evaluated and their antioxidant activity determined. All the preparations showed a quite similar polyphenol composition and comparable percentage even if ESIT12 was found to be richer in phenolic acids (caffeic, coumaric, ferulic, and isoferulic). Overall, flavones and flavonols ranged from ~20% up to ~36% in the glyceric extract, while flavanones and diidroflavonols were between ~28% and ~41%. Besides their quite similar composition, glycolic and hydroalcoholic extracts were found to be richer in the total polyphenols content. When the antioxidant properties were determined for the four preparations, the activity was similar among them, thus revealing that it is strictly related to the polyphenols content for propolis products whose composition is quite comparable. To date, very few data are available on propolis composition in glyceric and glycolic extracts and information has never been published on propolis in oil. This study could be of interest to the food and nutraceutical industries to choose suitable solvents and conditions to produce propolis preparations useful for active finished products
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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