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.
DittrichM. (1977) Cinareae - systematic review. In The Biology and Chemistry of the Compositae. HeywoodVH, HarborneJB, TurnerBL (Eds). Academic Press, London, New York, San Francisco, 999–1015.
WagenitzG, HellwigFH. (1996) Evolution of characters and phylogeny of Centaureinae. In: HindDJN, BeentjeHJ. (Eds) Compositae. Systematics. Proceedings of the International Compositae Conference. Vol. 1, Royal Botanic Gardens, Kew, UK, 491–510.
4.
GreuterW, WagenitzG, AgababianM, HellwigF. (2001) Proposal to conserve the name Centaurea (Compositae) with a conserved type. Taxon, 50, 1201–1205.
5.
GreuterW. (2003) The Euro+Med treatment of Cardueae (Compositae) - generic concepts and required new names. Willdenowia, 33, 49–61.
6.
WagenitzG. (1975) Pollenomorphologie und Systematik in der Gattung Centaurea L. s.l. Flora, 142, 213–279.
7.
HellwigFH. (2004) Centaureinae (Asteraceae) in the Mediterranean - history of ecogeographical radiation. Plant Systematics and Evolution, 246, 137–162.
8.
KožuharovS. (Ed.) (1992) A field guide to the Bulgarian vascular plants. Sofia: Bulgarian Academy of Sciences.
9.
VelchevV. (Ed.) (1992) Atlas of the endemic plants in Bulgaria. Sofia: Bulgarian Academy of Sciences.
10.
DostálJ. (1976) GenusCentaurea L. In: TutinTG, HeywoodVH., BurgesNA., MooreDM, ValentineDH, WaltersSM, WebbDA (Eds.) Flora Europaea. Cambridge University Press, London New York Melbourne, vol. 4, 254–301.
11.
Garsia-JacasN, SusannaA, MozaffarianR, IlarsanR. (2000) The natural delimitation of Centaurea (Asteraceae: Cardueae): ITS sequence analysis of the Centaurea jacea group. Plant Systematics and Evolution, 223, 185–199.
12.
Garsia-JacasN, SusannaA, GarnatjeT, VilatersanaR. (2001) Generic delimitation and phylogeny of the subtribe Centaureinae (Asteraceae): a combined nuclear and chloroplast DNA analysis. Annals of Botany (London), 87, 503–515.
13.
FontM, GarnatjeT, Garcia-JacasN, SusannaA. (2002) Delineation and phylogeny of Centaurea sect. Acrocentron based on DNA sequences: a restoration of the genus Crocodylium and indirect evidence of introgression. Plant Systematics and Evolution, 234, 15–26.
14.
BanchevaS, RaimondoFM. (2003) Biosystematic studies of seven Balkan species from genus Cyanus (Compositae). Bocconea, 16, 507–527.
15.
BanchevaS, GeraciA, RaimondoFM. (2006) Genetic diversity in Centaurea cineraria gr. (Asteraceae) in Sicily using isozymes. Plant Biosystems, 140, 10–16.
16.
BanchevaS, GreilhuberJ. (2006) Genome size in Bulgarian Centaurea s.l. (Asteraceae). Plant Systematics and Evolution, 257, 95–117.
17.
ChristensenLP, LamJ. (1990) Acetylenes and related compounds in Cynareae. Phytochemistry, 29, 2753–2785.
18.
ChristensenLP, LamJ. (1991) Acetylenes and other constituents from Centaurea species. Phytochemistry, 30, 3289–3292.
19.
QuintanaN, WeirTL, DuJ, BroecklingCD, RiederJP, StermitzFR, PaschkeMW, VivancoJM. (2008) Phytotoxic polyacetylenes from the roots of Russian knapweed [Acroptilon repens (L.) DC]. Phytochemistry, 69, 2572–2578.
20.
BentameneA, BazM, BouchehamR, BenayacheS, CrecheJ, BenayacheF. (2008) Flavonoid aglycones from Centaurea sphaerocephala. Chemistry of Natural Compounds, 44, 234–235.
21.
AkkalS, BenayacheF, MedjroubiK, TillequinF. (2007) Flavonol glycosides from Centaurea furfuracea. Antiplasmodial and cytotoxic activities. Chemistry of Natural Compounds, 43, 319–320.
22.
ShoebM, MacManusSM, KumarasamyY, JasparM, NaharL, Thoo-LinPK, NazemiyehH, SarkerSD. (2006) Americanin, a bioactive dibenzylbutyrolactone lignan, from the seeds of Centaurea americana. Phytochemistry, 67, 2370–2375.
23.
ErdemgilFZ, RosselliS, MaggioA, RaccugliaRA, KisielW, MichalskaK, CelikS, BrunoM. (2006) An unusual pregnane derivative and dibenzylbutyrolactone lignans from Centaurea sclerolepis. Polish Journal of Chemistry, 80, 647–650.
24.
KoukoulitsaE, SkaltsaH, KariotiA, DemetzosC, DimasK. (2002) Bioactive sesquiterpene lactones from Centaurea species and their cytotoxic/cytostatic activity against human cell lines in vitro. Planta Medica, 68, 649–652.
25.
JanackovicP, TesevicV, MilosavljevicS, VajsV, MarinPD. (2004) Sesquiterpene lactones, lignans and flavones of Centaurea affinis. Biochemical Systematics and Ecology, 32, 355–357.
26.
RosselliS, MaggioA, RaccugliaRA, SimmondsMSJ, ArnoldNA, BrunoM. (2006) Guaianolides from the aerial parts of Centaurea hololeuca. Natural Product Communications, 1, 281–285.
27.
KariotiA, SkaltsaH, LazariD, SokovicM, GarciaB, HarvalaC. (2002) Secondary metabolites from Centaurea deusta with antimicrobial activity. Zeitschrift fuer Naturforschung, Journal of Biosciences, 57C, 75–80.
28.
YesiladaE, GurbuzI, ShibataH. (1999) Screening of Turkish anti-ulcerogenic folk remedies for anti-Helicobacter pylori activity. Journal of Ethnopharmacology, 66, 289–293.
29.
KeryA, TawaijHAA, Al-KazrajiNK. (1985) Methylated flavones from Centaurea phyllocephala L. Herba Hungarica, 24, 183–194.
BarreroAF, OltraJE, AlvarezM, RaslanDS, SaudeDA, AkssiraM. (2000) New source and antifungal activity of sesquiterpene lactones. Fitoterapia, 71, 60–64.
32.
StevensKL, MerrilGB. (1985). Sesquiterpene lactones and allelochemicals from Centaurea species. ACS Symposium Series, 268, 83–98.
33.
TukovFF, AnandS, GadepalliRSVS, GunatilakaAAL, MathewsJC, RimoldiMJ. (2004) Inactivation of the cytotoxic activity of repin, a sesquiterpene lactone from Centaurea repens. Chemical Research in Toxicology, 17, 1170–1176.
34.
ShoebM, CelikS, NaharL, MacManusSM, Kong-Thoo-LinP, JasparsM, SarkerSD. (2007).Two salonitenolide derivatives from the aerial parts of Centaurea gigantea inhibit the growth of colorectal cancer cells in vitro. Natural Product Communications, 2, 121–125.
35.
FormisanoC, MignolaE, SenatoreF, BanchevaS, BrunoM, RosselliS. (2008) Volatile constituents of the aerial parts of Centaurea sibthorpii (Sect. Carduiformes, Asteraceae) from Greece and their biological activity. Natural Product Research, 22, 840–845.
36.
FormisanoC, RiganoD, SenatoreF, BrunoM, RosselliS.RaimondoFM, SpadaroV. (2008) Chemical composition of the essential oils of Centaurea sicana and C. giardinae growing wild in Sicily. Natural Product Communications, 3, 919–922.
37.
Garcia-JacasN, UysalT, RomashchenkoK, Suàrez-SantiagoVN, ErtuğrrulK, SusannaA. (2006). Centaurea revisited: A molecular survey of the Jacea group. Annals of Botany, 98, 741–753.
38.
TrendafilovaA, TodorovaM, BanchevaS. (2008) Secondary metabolites from Centaurea moesiaca. Biochemical Systematics and Ecology35, 544–548.
39.
ShoebM, MacManusSM, JasparsM, NaharL, Kong-Thoo-LinP, CelikS, SarkerSF. (2007) Lignans and flavonoids from the seeds of Centaurea bornmuelleri Hausskn. ex Bornm. and Centaurea huber-marathii Wagenitz. Polish Journal of Chemistry, 81, 39–44.
40.
FlaminiG, TebanoM, CioniPL, BagciY, DuralH, ErtugrulK, UysalT, SavranA. (2006) A multivariate statistical approach to Centaurea classification using essential oil composition data of some species from Turkey. Plant Systematics and Evolution, 261, 217–228.
41.
JenningsW, ShibamotoT. (1980) Qualitative Analysis of Flavour and Fragrance volatiles by Glass Capillary Gas Chromatography. Academic Press, New York.
42.
DaviesNW. (1990) Gas chromatographic retention indexes of monoterpenes and sesquiterpenes on methyl silicone and Carbowax 20M phases. Journal of Chromatography A, 503, 1–24.
43.
AdamsRP. (2007) Identification of Essential Oil Components by Gas Chromatography/Mass Spectroscopy, 4th Edn, Allured Publishing Co. Carol Stream, Illinois.
