Enantiomeric Distribution of Terpenoids in Juniperus Essential Oils: Composition of Juniperus horizontalis and Juniperus scopulorum Leaf Essential Oils From Southwestern Idaho

Abstract

The essential oils from the leaves and twigs of Juniperus horizontalis and Juniperus scopulorum, growing in southwestern Idaho, were obtained by hydrodistillation and analyzed by gas chromatography–mass spectrometry (GC-MS) and gas chromatography–flame ionization detection (GC(FID)). The major components in the essential oil of J horizontalis were α-pinene, 16.9%, predominantly ( + )-α-pinene; sabinene, 37.1%, exclusively ( + )-sabinene; myrcene, 5.0%; and terpinene-4-ol, predominantly ( + )-terpinen-4-ol. The essential oil of J scopulorum was rich in sabinene, 29.8%, exclusively ( + )-sabinene; terpinene-4-ol, 13.2%, nearly racemic; α-elemol, 9.7%; and 8α-acetoxyelemol, 6.4%. In addition, 12 commercial Juniperus communis fruit essential oils were analyzed by chiral GC-MS. α-Pinene showed considerable variation in enantiomeric distribution, depending on geographical location. The dominant enantiomer of sabinene in J communis essential oils was ( + )-sabinene.