Intraspecific chemical variability of essential oil from leaves of Cupressus atlantica Gaussen, an endemic and endangered coniferous species in Morocco

The composition of essential oils isolated from leaves of 11 natural populations of Cupressus atlantica, an endemic and endangered coniferous species from Morocco, was investigated by GC-MS. In total, 42 essential oil components were identified, accounting for 73.1–97.7% of the total oil. Monoterpene (25.2–84.9%) and sesquiterpene hydrocarbons (12.2–46.8%) were the principal subclasses of compounds, with α-pinene (15–65.4%), germacrene D (5.9–30.5%), δ-3-carene (2–16.6%) and γ-cadinene (1.3–9.8%) as the main constituents. The results of the oil composition were analysed by hierarchical cluster and principal component analysis that established three main groups of essential oils. These oils were differentiated by the content of the major constituents (α-pinene, germacrene D, δ-3-carene and γ-cadinene), geographical location and climatic characteristics.