1,720,961 research outputs found
Flavonoids from carnation (Dianthus caryophyllus) and their antifungal activity
No full textA flavonoid glycoside, kaempferol 3-O-beta-D-glucopyranosyl (1 -> 2)-O-beta-D-glucopyranosyl (1 -> 2)-O-[alpha-L-rhamnopyranosyl-(1 -> 6)]-beta-D-glucopyranoside (1), along with two known C- and O-flavonoid glycosides (2 and 3, respectively), were isolated from carnation (Dianthus caryophyllus). The structures of the isolated compounds have been elucidated unambiguously by UV, MS, and a series of ID and 2D NMR analyses. The isolated compounds and other flavonoid glycoside analogues exhibited antifungal activity against different Fusarium oxysporum f.sp. dianthi pathotypes. (C) 2008 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved
Paviosides A-H, eight new oleane type saponins from Aesculus pavia with cytotoxic activity
No full textA phytochemical analysis of Aesculus pavia has led to the isolation of eight novel triterpenoid saponins, based on oleane type skeleton and named paviosides A-H (1a, 1b-4a, 4b). On the basis of chemical, and 2D NMR and mass spectrometry data, the structures of the new compounds were elucidated as 3-O-[beta-D-xylopyranosyl(1 -> 2)] [-beta-D-glucopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (1a), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-glucopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (1b), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-galactopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (2a), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-galactopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (2b), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-xylopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (3a), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-xylopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (3b), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-xylopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl protoaescigenin (4a), and 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-xylopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl protoaescigenin (4b). The compounds showed cytotoxic activity on J-774, murinemonocyte/macrophage, and WEHI-164, murine fibrosarcoma, cell lines. Among them, paviosides E-H (3a, 3b and 4a, 4b) showed higher activity with values ranging from 2.1 to 3.6 mu g/mL. Structure-activity relationship studies indicated the positive effect on the activity of xylose unit in the place of glucose, while a little detrimental effect is observed when glucose is substituted by galactose. The aglycone structure and the presence of a tigloyl or an angeloyl group at C-21 do not affect significantly the inhibitory activity on both tested cell lines. (C) 2012 Elsevier Ltd. All rights reserved
Aesculus pavia foliar saponins: defensive role against the leafminer Cameraria ohridella.
Full text linkThe effects of phytoestrogens have been studied in the hypothalamic-pituitary-gonadal axis and in various
non-gonadal targets. Epidemiologic and experimental evidence indicates a protective effect of phytoestrogens
also in colorectal cancer. The mechanism through which estrogenic molecules control colorectal cancer tumorigenesis
could possibly involve estrogen receptor β, the predominantly expressed estrogen receptor subtype in
colon mucosa.
To validate this hypothesis, we therefore used an engineered human colon cancer cell line induced to overexpress
estrogen receptor β, beside its native cell line, expressing very low levels of ERβ and not expressing
ERα; as a phytoestrogenic molecule, we used kaempferide triglycoside, a glycosylated fl avonol from a Dianthus
caryophyllus cultivar. The inhibitory properties of this molecule toward vegetal cell growth have been previously
demonstrated: however, no data on its activity on animal cell or information about the mechanism of this
activity are available. Kaempferide triglycoside proved to inhibit the proliferation of native and estrogen receptor
β overexpressing colon cancer cells through a mechanism not mediated by ligand binding dependent estrogen
receptor activation. It affected HCT8 cell cycle progression by increasing the G0/G1 cell fraction and in
estrogen receptor β overexpressing cells increased two antioxidant enzymes. Interestingly, the biological effects
of this kaempferide triglycoside were strengthened by the presence of high levels of estrogen receptor β.
Pleiotropic molecular effects of phytoestrogens may explain their protective activity against colorectal cancer
and may represent an interesting area for future investigation with potential clinical application
Pavietin, a coumarin from Aesculus pavia with antifungal activity
No full textA new prenylated coumarin, S-6-[2-(hydroxymethyl)butoxyl-7-hydroxy-4-methyl-2H-chromen-2-one (1), named pavietin, has been isolated from the leaves of an Aesculus pavia genotype along with three known flavonol glycosides, quercetin 3-O-alpha-rhamnoside (quercitrin, 2), quercetin 3-O-alpha-arabinoside (3), and isorhamnetin 3-O-alpha-arabinoside (distichin, 4). The chemical structure of compound 1 was determined by chemical and spectroscopic methods, inclusive of UV, MS, and ID and 2D NMR experiments. It showed appreciable antimicrobial properties against several pathogens, displaying a significant antifungal activity toward one of the main fungal parasites of Aesculus species, Guignardia aesculi. The same biological tests performed with a mixture of flavonoids 2-4 resulted in weak or no activity. Compound 1 was undetectable in Aesculus hippocastanum, a closely related species lacking resistance to fungal pathogens. The possible role of 1 in plant resistance is discussed
Kaempferide triglycoside: a factor of resistance of carnation (Dianthus caryophyllus) to Fusarium oxysporum f. sp. dianthi.
No full textA kaempferide triglycoside has been found as a constitutive component in an uninfected carnation (Dianthus caryoplyllus) of the cultivar Novada. The chemical structure has been determined mainly by the use of spectroscopic methods, including 2D NMR experiments. It showed a strong activity in restricting fungal parasite development, which could contribute to the known ability of carnation cv. Novada to resist to Fusarium oxysporum f. sp. dianthi infection
Phenol Composition and Susceptibility to FusariumOxysporum Dianthi in Carnation
No full textPhenol composition of two carnation (Dianthus caryophyllus) cvs “Gloriana” and “Roland”, partially and highly resistant
to F. oxysporum f. sp. dianthi, respectively, has been investigated with the aim of assessing the possible role of phenolic
constituents both as biochemical markers of resistance and antifungal molecules. Analyses were performed through chromatography, NMR and MS methods. The results indicate that protocatechuic and vanillic acids are present in healthy and infected tissues of both
cvs; the flavonol glycoside peltatoside. 2,6-Dimethoxybenzoic acid was detected in small amounts only in infected “Gloriana” cv
while the highly resistant “Roland” cv contained the flavone datiscetin. This latter compound, due to its noticeable antifungal
activity evidenced in in vitro trials, could be conceived both as a biochemical marker of resistance towards this pathogen and
as a phytoanticipin
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
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