Fatty acid composition of the cypselae of two endemic Centaurea species (Asteraceae)

Abstract

The fatty acid composition of cypselae of two endemic species from Macedonia, Centaurea galicicae and C. tomorosii, is analysed for the first time, using GC/MS (gas chromatography/mass spectrometry). In the cypselae of C. galicicae, 11 fatty acids were identified, palmitic (hexadecanoic) acid (32.5%) being the most dominant. Other fatty acids were elaidic [(E)-octadec-9-enoic] acid (13.9%), stearic (octadecanoic) acid (12.8%) and linoleic [(9Z,12Z)-9,12-octadecadienoic] acid (10.6%). Of the 11 identified fatty acids, seven were saturated fatty acids, which represented 41.5% of total fatty acids, while unsaturated fatty acids altogether constituted 58.5%. In the cypselae of C. tomorosii, five fatty acids were identified. The major fatty acid was linolelaidic [(9E,12E)-octadeca- 9,12-dienoic] acid (48.8%). The second most dominant fatty acid was oleic [(9Z)-octadec-9-enoic] acid (34.2%). Thus, unsaturated fatty acids were present with 83%. The other three fatty acids identified were saturated fatty acids, which represented 17% of total fatty acids. As a minor fatty acid, levulinic (4-oxopentanoic) acid was determined in both C. galicicae and C. tomorosii (0.3% and 3.2%, respectively). The obtained results differ from published data on dominant fatty acids in the cypselae of other species belonging to the same section as the species investigated in the present paper (section Arenariae, subgenus Acrolophus, genus Centaurea). They also, differ from published data referable to other genera belonging to the same tribe (Cardueae). The general chemotaxonomic significance of fatty acids is discussed. © 2017 Institute of Botany and Botanical Garden Jevremovac, Belgrade.