Five known flavonoids (1-5) and three sesquiterpene lactones (6-8) are reported for the first time from the endemic species Centaurea sulphurea Willd. (Asteraceae). Compound 7 is a new heliangolide (6R, 7R, 8S, 3'R)-8α-(3’,4’-dihydroxy-methylene-2’-butanoyloxy)-15-oxo-helianga-1(10), 4(5), 11(13)-trien-6,12-olide, named as sulphurein.
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6.
SkaltsaH, LazariD, GeorgiadouE, KakavasS, ConstantinidisT. (1999) Sesquiterpene lactones from Centaurea species: C. thessala Hausskn. subsp. drakiensis (Freyn & Sint.) Georg and C. attica Nym. subsp. attica. Planta Medica, 65, 393;
7.
SkaltsaH, LazariD, PanagouleasC, GeorgiadouE, GarciaB, SokovicM. (2000) Sesquiterpene lactones from Centaurea species: C. thessala and C. attica. Antifungal activity. Phytochemistry, 55, 903–908;
8.
RosselliS, MaggioAM, RaccugliaRA, SimmondsMSJ, ArnoldAN, BrunoM. (2006) Guaianolides from the aerial parts of Centaurea hololeuca. Natural Product Communications, 1, 281–285.
9.
RosselliS, MaggioA, RaccugliaRA, BrunoM. (2003) Rearrangement of germacranolides. Synthesis and absolute configuration of elemane and heliangolane derivatives from cnicin. European Journal of Organic Chemistry, 14, 2690–2694;
NowakG, DrozdzB, GeorgiadisT. (1984) Sesquiterpene lactones. XXIX. Cnicin in species of the subgenus Acrolophus (Cass.) Dobrocz. Acta Societatis Botanicorum Poloniae, 53, 199–205.
