1,720,973 research outputs found
Iridoids and phenylethanoid glycosides from the aerial parts of Ajuga tenorei, an endemic Italian species
No full textWe report the first analysis in absolute, and in particular, concerning the phytochemical pattern, about an endemic Italian species, Ajuga tenorei C. Presl. The analysis, performed by means of techniques such as Column Chromatography and NMR spectroscopy and Mass spectrometry, led to the isolation and the identification of five compounds namely verbascoside (1), echinacoside (2), ajugoside (3), harpagide (4) and 8-O-acetylharpagide (5). The presence of these compounds is important from both chemotaxonomic and ethno-pharmacological point of view. For what concerns the first point is confirmed the correct botanical classification of the species. The isolated compounds are also known to exert peculiar pharmacological activities and their presence may give a rationale to the historical medicinal properties associated to the Ajuga genus in general, since these plants have a long traditional use in many parts of the world. Such fact might suggest the use of also this species in this sense
Phytochemicals from the rhizomes of Iris marsica I. Ricci & Colas. collected from Majella National Park
No full textFirst total phytochemical analysis on the aerial parts of an endemic Italian species: Ajuga tenorei C. Presl
No full textIn this work, we report the first analysis in absolute about an endemic Italian plant, Ajuga tenorei C. Presl and in particular we focused on its phytochemical pattern. A. tenorei C. Presl (A. acaulis Brocchi), better known with the common name of Tenore's Bugle, is a herbaceous perennial plant belonging to the tribe Ajugoideae of the Lamiaceae family. From a botanical standpoint, this species is mainly characterized by the fact that it has no stem or this is very short for which it can be easily distinguished from the other species of the genus. Its height can reach up to 10 cm. Its leaves are all collected in a basal rosette and have an oblanceolate shape and are crenate. The flowers are small and are blue-violet colored blooming from May to June. Its habitat is represented by rocky forests and calcareous soils from 1200 to 2200 m a.s.l. This species is endemic in Italy, typically located in the Central and Southern regions even with many exceptions. Several species of the Ajuga genus own an ancient traditional use in folk medicine in many areas of the world for several disorders and against several diseases but are also noted for other pharmaceutical activities. The studied sample was collected within the “Majella” National Park territory and in particular, in the town of Rivisondoli in the province of L’Aquila (Abruzzo Region, Central Italy) (geographic coordinates: 41°86'13'' N; 13°98'99'' E) during August, 2015 at an altitude of about 1750 m a.s.l. The phytochemical analysis was performed on the ethanolic extract and we used techniques such as classical Column Chromatography for the separation of the polar compounds and NMR spectroscopy and Mass spectrometry for their identification.
This procedure evidenced the presence of five compounds namely verbascoside (1), echinacoside (2), ajugoside (3), harpagide (4) and 8-O-acetylharpagide (5), which are important for two different points of view: chemotaxonomy and ethno-pharmacology. For what concerns the first one, all these compounds have already been reported in the genus and in the family but also in other correlated families like Scrophulariaceae or Orobanchaceae confirming the botanical classification of this species and the systematic proximity of all these families. By the way compounds (1) and (2) are very common phenyl-ethanoid glycosides and the iridoid compounds (3), (4) and (5) are considered chemotaxonomic markers respectively of the genus and the family. For what concerns the second point, instead, they all present strong pharmacological activities i.e. anti-inflammatory and anti-bacterial which might suggest the possibility of a future employment of this species in medicine, too
Study on the molecular composition of an indigenous Italian species. Coristospermum cuneifolium (Guss.) Bertol
No full textIn this work, the first complete phytochemical analysis of an Italian native species called Coristospermum cuneifolium (Guss.) Bertol. [previously classified as Ligusticum lucidum Mill. subsp. cuneifolium (Guss.) Tammaro)], is reported. Both the polar and the less polar compounds were investigated and this was performed by means of chromatographic and spectroscopic techniques. This study allowed the isolation and the identification of eleven constituents, with chemosystematic and pharmacologic relevance, belonging to different classes of natural products. In particular, these were rutin (1), vervenone-5-O-β-D-glucopyranoside (2), vervenone-8-O-β-D-glucopyranoside (3), siphonoside (4), chlorogenic acid (5), quinic acid (6), (8S,9R)-9-acetoxy-8-O-isovaleroyl-8,9-dihydrooroselol (7), peucenidin (8), oxypeucedanin (9), 7-hydroxycoumarin (10) and pheophorbide A ethyl ester (11). The chemotaxonomic markers of the family were recognized together with compounds resulted to be new phytochemicals for the genus or with a limited distribution in Apiaceae. These constituents may be considered as further taxonomic markers for classification of the Apioideae subfamily. The presence of these metabolites also permitted to provide a phytochemical rationale for the use of Ligusticum s.l. in traditional medicine and proved that also C. cuneifolium has a potential in medicine field as well, since cytotoxic components, that might represent a further specific pharmacological property, were recognized
Secondary metabolites with ecologic and medicinal implications in Anthemis cretica subsp. petraea from Majella National Park
Get PDFAnthemis cretica subsp. petraea (Ten.) Greuter is a plant belonging to the Asteraceae family and endemic of central Italy. In this paper, the first analysisof the ethanolic fraction of samples collected in the Majella National Park is reported. Seven compounds were isolated and identified namely parthenolide (1), 9α-acetoxyparthenolide (2), tamarixetin (3), 7-hydroxycoumarin (4), 4'-hydroxyacetophenone (5), leucanthemitol (conduritol F) (6),and proto-quercitol (7). Isolation of the compounds was achieved by means ofcolumn chromatography (CC), while their identification was achieved through spectroscopic and spectrometric techniques. The presence of these compounds is of great relevance. Compounds 1 and 2 are chemosystematic markers of the family, thus confirming the correct botanical classification of the species. Conversely, compounds 3, 5,and 7 were identified for the first time in the species and, instead, confirm the tendency of endemic entities to develop characteristic metabolite patterns in respect to cosmopolite species. Moreover, the presence of compounds 6 and 7 has ecologic implications and may be linked to this taxon’s adaption to dry environments. The production of these osmolytes may, in fact, represent the reason why this species is able to survive in extreme conditions of aridity. Lastly, from a medicinal standpoint, the isolated compounds are endowed with interesting biological activities and may justify, on a molecular base, the widespread traditional uses of the Anthemis species, as well as a basis for the use ofthe subspecies petraea
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
- …
