1,720,992 research outputs found
Antioxidant activity of Laurus nobilis
No full textLaurus nobilis L. (Lauraceae) is an evergreen tree widely distributed in the Mediterranean area and the leaves are extensively used as a spice for culinary and flavouring purposes. In the Sardinian traditional medicine the leaves decoction or infusion are widely used in the treatment of different diseases (1). Previous phytochemical investigations lead to the isolation of several classes of secondary metabolites and in particular sesquiterpene lactones, alkaloids, catechin and procyanidine derivatives, flavonoids and megastigmane glucosides (2).
In this work the antioxidant properties of L. nobilis extracts were investigated. Sequential extracts were prepared using solvents in increasing polarity (petroleum ether, chloroform and methanol). In addition the leaves infusion was prepared and analysed. The residues were evaluated for their antioxidant activity with different in vitro methods (DPPH, TEAC and BR) (3). The antioxidant activity was established in the methanol extract. Phytochemical investigations lead to the isolation of five kaempferol-O-glycosides, five quercetin-O-glycosides and one catechin. In addition a flavone C-glycoside, 5,7,4’-trihydroxy-6-C--D-glyucopyrano-2’’-O--L-rhamnopyranoside was isolated and characterized. Structures of isolated compounds were achieved on the basis of HR-MS spectra as well as 1D and 2D NMR experiments. The our results showed a linear correlation between the antioxidant activity and the total phenol content of the extracts. The our results showed that the total antioxidant capacities from DPPH, TEAC and BR assays were highly correlated with phenolic content (r2 = 0,915, 0,971 and 0,952, respectively).
References: 1. Loi M.C.et al.. (2004) Fitoterapia 75, 277-295. 2. De Marino S. et al.( 2004) J. Agric. Food. Chem.52, 7525-7531 and references therein. 3. Cervellati R. et al. (2002) J. Agric. Food Chem., 50, 7504-7509
Effects of differential extraction of Verbena officinalis on rat models of inflammation, cicatrization and gastric damage
No full textPlanta Med. 2007 Mar;73(3):227-35. Epub 2007 Mar 12.
Effects of differential extraction of Verbena officinalis on rat models of inflammation, cicatrization and gastric damage.
Speroni E, Cervellati R, Costa S, Guerra MC, Utan A, Govoni P, Berger A, Müller A, Stuppner H.
Source
Dipartimento di Farmacologia, Università di Bologna, Bologna, Italy. [email protected]
Abstract
Verbena officinalis L. is used in folk medicine for the treatment of inflammatory disorders, skin burns, abrasions, and gastric diseases. Extracts obtained with different solvents (methanol, VoME; enriched flavonoids, VoEF; supercritical CO2, VoCO2) were evaluated for anti-inflammatory, gastroprotective and cicatrizing activities. Additionally, the antioxidant capacity was determined in vitro. In order to confirm the activities investigated, histological observations were performed. All extracts induce a remarkable anti-inflammatory activity. The gastric damage is significantly reduced by all extracts administered, whereby the most pronounced protection is observed for the VoCO2 and VoEF extracts. Finally, a wound healing effect is obtained particularly by the CO2 extract, suggesting the presence of some lipophilic active principles. Histological evidence confirms the results evaluated with the animal procedures. The results obtained after oral administration of V. officinalis extracts are also in agreement with the antioxidant capacity evaluated in vitro, confirming the relationship between pharmacological activities and antiradical efficacy
Evaluation of in vitro antioxidant properties of some traditional Sardinian medicinal plants: Investigation of the high antioxidant capacity of Rubus ulmifolius
No full textThe antioxidant capacities of 11 botanical species used in the tradition of Sardinia as teas beverages or as decoction for medicinal
purposes were evaluated using different in vitro methods (BR, TEAC, DPPH and FC). Among the various species, Rubus ulmifolius,
resulted the more active with all the used methods. Phytochemical investigation on the extract yields in the isolation of several phenolic
compounds namely caffeic acid, ferulic acid, quercetin-3-O-glucuronide, kaempferol-3-O-glucuronide, kaempferol-3-O-(600-p-coumaroyl)-
b-D-glucopyranoside, kaempferol-3-O-(600-caffeoyl)-b-D-glucopyranoside, chlorogenic acid, 4-caffeoylquinic acid and 5-caffeoylquinic
acid. The antioxidant activity of isolated compounds was also evaluated
Deoxypodophyllotoxin content and antioxidant activity of aerial parts of Anthriscus sylvestris Hoffm.
Full text linkDeoxypodophyllotoxin content of the aerial parts of Anthriscus sylvestris Hoffm. growing at different altitudes was evaluated in comparison to the roots. The lignan accumulation in ground parts was at least double compared to aerial ones.
In addition antioxidant-guided fractionation of the crude methanol extract of aerial parts was performed with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) test. Active fractions contained mainly luteolin-7-O-glucoside and chlorogenic acid. Antioxidant properties of both crude extract and isolated compounds were also investigated with the Briggs-Rauscher (BR) oscillating reaction. A satisfactory agreement between the results obtained with the two methods was observed
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
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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