1,721,031 research outputs found
Comparative chemical composition, free radical-scavenging and cytotoxic properties of essential oils of six Stachys species from different regions of the Mediterranean Area
No full textThe chemical composition of essential oils of six Stachys species, S. cretica L ssp. vacillans Rech. fil., S. germanica L, S. hydrophila Boiss., S. nivea Labill., S. palustris L. and S. spinosa L., obtained by hydrodistillation, was studied by GC and GC-MS. All the oils have in common a great percentage of fatty acids and esters (24.2-58.5%) and a high amount of sesquiterpenes (16-35.9%). with the exception of the oil from S. palustris, which consisted mainly of carbonylic compounds (25.4%). The antioxidant activity by DPPH test and the anti proliferative activity on a series of human cancer cell lines (02, amelanotic melanoma and ACHN, renal cell adenocarcinoma) were investigated for all the oils. S. palustris, S. cretica and S. hydrophila showed the highest antiradical effect, with IC(50) values of 0.482, 0.652 and 0.664 mg/ml, respectively. The most anti proliferative essential oil against C32 cell line was the oil of S. germanica with a 77% of inhibition at a concentration of 100 mu g/ml. S. germanica, S. palustris and S. spinosa showed the most antiproliferative activity on ACHN cell line, at a concentration of 100 mu g/ml,with 81%, 77% and 73% inhibition, respectively
Protection against neurodegenerative diseases of Iris pseudopumila extracts and their constituents
No full textThe present study describes for the first time the in vitro properties of Iris pseudopumila flowers and rhizomes extracts and their constituents. The methanolic extract of rhizomes showed significant anti-inflammatory activity through inhibition of NO production in the murine monocytic macrophage cell line RAW 264.7. Among the isolated compounds, those which most effectively inhibited LPS-induced NO production were irisolidone and 7-methyl-tectorigenin-4′-O-[β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside], with IC50 values of 23.6 μM and 29.4 μM respectively. Isoorientin and isovitexin exhibited the most promising activity against AChE with IC50 of 26.8 μM and 36.4 μM, respectively. The same compounds exhibited also the higher activity against BChE
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
In vitro evaluation of the anti-proliferative and geno-protective activity of traditional preparations of ayurvedic crude drugs
No full textThe research of new botanicals is an important aspect of the modern research focused on prevention and cure of cancer. This project evaluated the in vitro geno-protective capacity (SOS-Chromotest) and anti-proliferative activity (MCF7, A549, MDA-MB-231, LoVo, HepG2, K562, Jurkat and IB3-1 cell lines) of two traditional preparations, decoction and mother tincture, of two ayurvedic crude drugs: Hemidesmus indicus roots and Azadirachta indica leaves. Our previous results demonstrated an interesting antileukemic effect1,2 of H. indicus decoction. In present study both H. indicus preparations possess anti-proliferative activity against all the cell lines considered. Among phytochemical markers, the most active, 2-hydroxy-4-methoxybenzaldehyde, showed an IC50 of 12.09±2.78 μg/ml against K562 and an IC50 of 13.15±5.57 μg/ml against Jurkat cells. The only relevant data for A. indica were against: MDA-MB-231 cell (IC50= 381.57±43.62 μg/ml) for decoction and K562 (IC50= 276.05±26.60 μg/ml) and Jurkat cells (IC50= 207.18±29.97 μg/ml) for mother tincture. Further analyses of anti-proliferative bioactivity for A. indica are still in progress.
In conclusion: H. indicus preparations were more effective than those of A. indica; mother tincture of both crude drugs showed a general wider anti-proliferative activity than decoction, in particular for H. indicus, it evidenced promising data against Jurkat (63.79±7.97 μg/ml), Hep-G2 (34.50±0.14) and LoVo (29.84±0.24); H. indicus mother tincture and decoction were more effective than 2-hydroxy-4-methoxybenzaldehyde against Hep-G2 cell, pointing out possible synergistic (agonistic) activity of minor compounds
Phytochemicals with potential anti-obesity properties
No full textIncidence of obesity has reached an alarming rate worldwide. Obesity is the most prevalent
nutritional disease and a major public health problem both in developed and undeveloped countries
increasing the risk of metabolic disorders, chronic and cardiovascular diseases. It has been shown
that obesity is associated with a chronic inflammatory status in adipose tissue and activation of
oxidative stress. In addition, it involves a disfunctional intestinal barrier inducing alteration in its
permeability. Plants provide a major dietary source of phytochemicals with anti-obesity potential
since many of them, having antioxidant properties, should be able to relieve oxidative stress
resulting from inflammation. In continuation of our studies on plants as a supply of valuable
compounds with anti-obesity potential, we have investigated by a classical electrophysiology
approach the effects of selected plant extracts on Model Planar Lipid Membranes (PLMs) made up
of dioleoyl-phosphatidylserine:dioleoyl-phosphatidylethanolamine:palmitoyl-oleoylphosphatidylcholine
(27:27:18, w:w:w), a surrogate of intestinal membranes. In particular, the
hydroalcholic (70% EtOH) extract from the dry tunics of A. cepa var. Tropea was effective in forming
channel-like pathways in the lipid bilayer. Electrophysiological data demonstrated that the extract
was able to interact with the PLMs forming stable pores. This effect was also detectable with
quercetin, the main component of the extract, that was able to interact with the PLMs and form
stable pores in the ranges of applied voltages from 60 to 20 mV and from -60 to -20mV. The
conductance values seemed to be inversely dependent on applied voltage thus suggesting that
quercetin like the whole extract of A.cepa forms aqueous ion pathways thus modulating membrane
permeability. Very interestingly, glycosylation of the molecule resulted in loss of activity
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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