The chemical composition of the essential oil of Ptilostemon gnaphaloides subsp. pseudofruticosus (Asteraceae) growing in Kythira Island, Greece

Ptilostemon is a small genus of the subtribe Carduinae (Asteraceae) that includes 15 species as annual or perennial herbs or small shrubs, spread in the Mediterranean arch, from Crimea and Turkey to the Iberian Peninsula and Morocco. Several species of this genus have been studied for the content of non-volatile metabolites whereas few investigations have been carried out on their essential oils. In the present study the chemical composition of the essential oil from aerial parts of Ptilostemon gnaphaloides subsp. pseudofruticosus, belonging to Section Ptilostemon, endemic of South Greece and Turkey, and collected in the island of Kythira, was analyzed by GC-MS. The result showed the presence of large quantity of sesquiterpene hydrocarbons with germacrene D (20.0%) as the most abundant component, followed by (E)-caryophyllene (6.8%). Among the other metabolites hexacosane (29.1%) and manoyl oxide (12.1%) were the most abundant.