Search results for "Centaurea"
showing 10 items of 89 documents
Cytotoxic activity of some natural and synthetic guaianolides
2005
Several natural guaianolides and synthetic derivatives of repin (1) were tested and found to be active against tumor cell replication. Repin (1) and both mono- and di-halohydrin analogues (2, 7-9, 11, 12) showed significant antitumor potency. A more effective compound (17) was obtained by esterificating repin with the paclitaxel side chain.
Volatile Components of Centaurea Bracteata and C. Pannonica subsp. Pannonica growing wild in Croatia
2010
This paper reports on the volatile components of oils from the aerial parts (CBA) and roots (CBR) of Centaurea bracteata Scop. and aerial parts of C. pannonica (Heuffel) Simonkai subsp. pannonica (CPA), two Asteraceae growing wild in Croatia. The volatile components, obtained by hydrodistillation, were determined by GC-MS analysis. The yields (w/w) of the dried oils were 0.10% (CBA), 0.22% (CBR) and 0.09% (CPA), respectively. A total of 91 compounds were identified accounting for 91.1%, 93.3% and 87.9% of the total oil for CBA, CBR and CPA, respectively. All the samples were characterized mainly by hydrocarbons (7.1-34.1%), fatty acids (9.7-45.9%), and oxygenated sesquiterpenes (15.2-16.6%…
Components from the Essential oil of Centaurea aeolica Guss. and C-diluta Aiton from Sicily, Italy
2015
Volatile components from florets, leaves and stems and branches of Centaurea aeolica Guss. harvested in Lipari, Sicily, Italy, were analysed by gas phase chomatography (GC) and gas chomatography mass spectrometry (GC-MS). The main constituents were β-eudesmol, caryophyllene oxide, ( E )-12-norcaryophyll-5-en-2-one and hexahydrofarnesylacetone in flowers, hexahydrofarnesylacetone, 2-methyloctadecane and tricosane in the leaves and hexadecanoic acid , caryophyllene oxide and β-eudesmol in the stems and branches . The analysis of the essential oil of the aerial parts of Centaurea diluta Aiton gave mainly fatty acids and derivatives, the main ones being hexadecanoic acid and (Z,Z)-9,12-octadeca…
Gel-electrophoretic description of European populations ofTerellia virens (Loew) (Diptera, Tephritidae); implications for its use as an agent for the…
1991
Allozyme frequencies of 15 enzyme loci, 14 of which were polymorphic, were used to characterize sevenTerellia virens populations originating from three allopatrically distributedCentaurea species. The two populations whose origins were geographically furthest apart, from Israel (onC. iberica) and from Switzerland (onC. vallesiaca), showed relatively high values of genetic distance from the 5 populations sampled in Austria and Hungary (onC. maculosa) (Nei's D>0.07). The latter five displayed a high degree of genetic similarity. No diagnostic (fixed) allelic differences were observed between these three groups ofT. virens populations, but they could be well characterized by significant differ…
Volatile components of aerial parts of Centaurea nigrescens an C. stenolepis growing wild in the Balkans
2010
The volatile constituents of the aerial parts of Centaurea nigrescens Willd, collected in Romania and of two samples of C. stenolepis A. Kerner from Bulgaria and Romania were obtained by hydrodistillation and analyzed. The main components of C. stenolepis were caryophyllene oxide (6.9-15.6%), hexahydrofarnesyl acetone (6.5-4.4%), heptacosane (6.0-4.9%) and p-vinyl guiacol (4.3-5.0%). The main components of C. nigrescens were caryophyllene oxide (9.9%), β-eudesmol (9.5%), spathulenol (7.6%), heptacosane (6.1%) and p-vinyl guiacol (5.5%). The chemotaxonomic significance with respect to their co-location in Sections Lepteranthus and Nigrescentes, respectively, is discussed.
Chemical composition of the essential oils of Centaurea formanekii and C. orphanidea ssp. thessala, growing wild in Greece.
2012
The volatile constituents of the aerial parts of Centaurea formanekii Halacsy and the aerial parts, capitula and roots of C. orphanidea Heldr. & Sart. ex Boiss. ssp. thessala (Hausskn.) Dostál from Greece were extracted by hydrodistillation and analyzed. The main components in C. formanekii were hexadecanoic acid (13.6%), δ-elemene (9.1%), and spathulenol (6.9%). The main components in C. orphanidea ssp. thessala were γ-elemene (26.1%) and caryophyllene oxide (13.2%) in the aerial parts, hexadecanoic acid (33.5%) and heptacosane (6.3%) in the capitula, and hexadecanoic acid methyl ester (22.0%) and α-chamigrene (14.0%) in the roots. The chemotaxonomic significance with respect to other…
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%). β-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%), spathule…
Chemical composition of the essential oils of Centaurea sicana and C. giardinae growing wild in Sicily
2008
The essential oils of Centaurea sicana (S) and C. giardinae (G) were studied by GC and GC-MS. Thirty constituents for S, representing 81.5% of the total oil, and 24 compounds for G (94.2% of the total) were identified. The oils were rich in sesquiterpenoids (47.9% for S and 54.7% for G) and hydrocarbons (25.9% for S and 31.7% for G). Germacrene D (13.3%), ( E)-β-farnesene (8.3%), nonacosane (7.3%), heptacosane (6.5%) and phytol (6%) were recognized as the main constituents for S, while caryophyllene oxide (17.7%), nonacosane (14.5%), germacrene D (11.5%), caryophyllene (11.2%) and heptacosane (10.3%) were the main compounds for G.
Cytotoxicity of 40 Egyptian plant extracts targeting mechanisms of drug-resistant cancer cells
2019
Abstract Background The multidrug resistance (MDR) phenotype encounters a major challenge to the success of established chemotherapy in cancer patients. We hypothesized that cytotoxic medicinal plants with novel phytochemicals can overcome MDR and kill MDR-cells with similar efficacy as drug sensitive cells. Purpose We evaluated plant extracts from an unexplored ecosystem in Egypt with unusual climate and nutrient conditions for their activity against sensitive and multidrug-resistant cancer cell lines. Material and methods/study design Methylene chloride: methanol (1:1) and methanol: H2O (7:3) extracts of 40 plants were prepared resulting in a sum of 76 fraction containing compounds with v…
The essential oil composition of Centaurea immanuelis-loewii Degen growing wild in Bulgaria and chemotaxonomy of section Acrocentron
2021
In the present study, the chemical composition of the essential oil from aerial parts of the Balkan endemic, Centaurea immanuelis-loewii Degen (sect. Acrocentron, Asteraceae), collected in Bulgaria was evaluated by GC-MS. The main components of the oil were β-caryophyllene (23.2%), germacrene D (13.7%) and caryophyllene oxide (12.4%). Furthermore, a complete literature review on the composition of the essential oils of all the other taxa of Centaurea, belonging to section Acrocentron, studied so far, was performed and the chemotaxonomical variations in the composition of the essential oils is discussed.