Essential oils from seven populations ofJuniperus brevifolia (Seub.) Antoine, an endemic species of the Azores

The composition of the essential oils isolated from twigs and from unripe berries of seven populations of Juniperus brevifolia (Seub.) Antoine, an endemic species of the Azorean archipelago, was analysed by GC and GC–MS. All oil samples were dominated by their monoterpene fraction (84–94%), limonene (41–79%) and α-pinene (6–40%) being the main oil components. The sesquiterpene fraction occurred in a concentration range of 1–10%. Diterpenes amounted to 6%, sandaracopimara-8(14),15-diene (up to 5%) being the main component of this fraction. Cluster analysis of the essential oils revealed two distinct groups, one from the twigs and the other from the berries. The enantiomeric composition of α-pinene and limonene showed a clear homogeneity between all the oil samples.