Search results for "Centaur"

Volatile components from flowers of Centaurea nicaeensis All., C. parlatoris Helder, C. solstitialis L., ssp. schouwii (DC.) Dostàl wild growing in S…

2008

The volatile constituents of the flowerheads of Centaurea nicaeensis All., C. parlatoris Helder and C. solstitialis L. ssp. schouwii (DC.) Dostal were extracted by hydrodistillation and analysed by GC and GC-MS. Altogether 113 components were identified. Fatty acids and hydrocarbons were the most abundant components in the oils. Caryophyllene and caryophyllene oxide were the main compounds of the sesquiterpene fraction. The study on the biological activity of the oils shows no significant activity.

Structure and stereochemistry of stenophyllolide, a germacrolide from Centaurea aspera var. Stenophylla

1984

Abstract A crystalline compound, named stenophyllolide, obtained from an extract of Centaurea aspera var. stenophylla was shown to be 9β,15-dihydroxygermacra-1(10),4,11-trien-6α,12-olide by X-ray analysis. The molecular structure of stenophyllolide was solved with orthorhombic space group P2 1 2 1 2 1 , a = 11.719 (5), b = 13.389 (5), c = 8.646 (5) A for Z = 4, by direct methods and refined to a final R of 0.06 for 1198 observed reflections.

Sesquiterpene lactones from Centaurea alba and C. conifera

1995

Abstract The aerial parts of Centaurea alba yielded five know germacranolides: salonitenolide, 11β, 13-dihydrosalonitenolide, salonitenolide 8- O -(4′-acetoxy-5′-hydroxy)-angelate, cnicin 4′-O-acetate and cnicin. The aerial parts of C. conifera yielded loliolide, 1β,6α-dihydroxy-4(15)-eudesmene, chlorojanerin, chlorohyssopifolin A (centaurepensin) and its C-17 epimer. The latter compound is described for the first time.

Cytotoxic activity of some natural and syntetic sesquiterpene lactones

2006

Several natural and synthetic sesquiterpene lactones with different skeletons were tested and found to be active against nine cancer cell lines. Elemane (4), heliangolane (5) and their hydroxy analogues 9 and 10, all containing an α,β-unsaturated aldehyde substituent, were the most potent compounds.

Nuevo híbrido del género Centaurea L. (Compositae) sección Seridia (Juss.) Czerep

2010

[EN] A new hybrid of the Centaurea L. genus (Compositae) is described: Centaurea x subdecurrens nothosubsp. oblanceolata (C. aspera subsp. stenophylla x C. seridis. subsp. cruenta). It is only found at the contact areas between the parental species, and is therefore a very rare taxon. Key words: Centaurea, hybrid, taxonomy.

Cytotoxic and chemotaxonomic study of isolated metabolites from Centaurea aegyptiaca

2020

Antiproliferative activity against leukemia cells of sesquiterpene lactones from the Turkish endemic plant Centaurea drabifolia subsp. detonsa

2017

The apolar organic extract obtained from aerial parts of Centaurea drabifolia Sibth. & Sm. subsp. detonsa (Bornm.) Wagenitz, growing wild in Turkey, was investigated for the first time for its secondary metabolite composition. Seven sesquiterpene lactones belonging to the guaiane class (1-7), including the new compound 4, along with a fatty acid lactone derivative (8), were isolated. The structures of these compounds were established by spectroscopic analysis, including 2D NMR spectroscopic techniques, with the stereostructure of the new guaiane 4 determined with the help of MTPA derivatization. Cytotoxic activities of compounds 1-7 were evaluated against two cancer cell lines, namely acute…

Volatile components from aerial parts of Centaurea gracilenta and C. ovina ssp. besserana growing wild in Bulgaria

2011

The essential oils of Centaurea gracilenta Velen. (CG) and C. ovina Pall. ex Willd. ssp. besserana (DC.) Dostál (COB) growing wild in Bulgaria, were studied by GC and GC-MS. Forty-five compounds for CG, representing the 90.1% of the oil, and 68 compounds for COB, representing the 91.9% of the oil, were identified. The oils were rich in sesquiterpenoids (33.4% for CG and 27.3% for COB), hydrocarbons (28.3% for CG and 10.7% for COB) and carbonylic compounds (12.7% for CG and 13.1% for COB). Fatty acids were abundant only for COB (31.3%). beta-Eudesmol (12.8%), nonacosane (11.8%) and p-vinyl guiacol (7.5%) were recognized as the main constituents for CG, while hexadecanoic acid (21.4%), spathu…

Correlation of the highest-energy cosmic rays with the positions of nearby active galactic nuclei

2008

Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of the cosmic rays with the ighest-energies, which are correlated with the positions of relatively nearby active galactic nuclei (AGN) [Pierre Auger Collaboration, Science 318 (2007) 938]. The correlation has maximum significance for cosmic rays with energy greater than ~6 x 1019 eV and AGN at a distance less than ~75 Mpc. We have confirmed the anisotropy at a confidence level of more than 99% through a test with parameters specified a priori, using an independent data set. The observed correlation is compatible with the hypothesis that cosmic rays with the highest-energies originate fro…

Copper binding capacity of root exudates of cultivated plants and associated weeds

2001

International audience; Cu binding to root exudates of two cultivated plants, wheat (Triticum aestivum) and rape (Brassica napus), and two weeds associated with wheat, dog daisy (Matricaria inodora) and cornflower (Centaurea cyanus), was studied in vitro under hydroponic and sterile conditions. Nutrient solutions were prepared with or without P. A MetPLATE microbiological test was used to assess the metal complexing capacity of root exudates. In the P-deficient solutions, no exudation was observed for any of the four plants; consequently, no Cu binding occurred. When P was present in the nutrient solutions, the plant exudates displayed differing abilities to complex Cu. No difference was de…