Fresh plant samples of A. arborescens growing in Sicily were collected from five different sites: Petru (N 37° 59′ 46″, E 13° 38′ 53″, 69 m); Diga (N 37° 57′ 23″, E 13° 39′ 05″, 198 m), Felice (N 37° 56′ 44″, E 13° 36′ 38″, 484 m), Torto (N 37° 57′ 53″, E 13° 46′ 30″, 55 m) and Artese (N 37° 58′ 28″, E 13° 44′ 13″, 10 m) in January 2010.

Forty-three compounds, accounting for more than 92% of the oil, were identified. Monoterpene fraction with the exception of Petru population was higher than the sesquiterpene fraction. beta-Thujone (20.5-55.9%), chamazulene (15.2-49.4%), camphor (1.3-10.7%) and germacrene D (2.3-3.4%) were the main compounds.