Gas-chromatographic analyses of volatile organic compounds in essential oils extracted from Slovak juniper berries and needles (Juniperus communis L.)

Abstract

Juniper essential oils (EOs) are mainly extracted from berries; however, nowadays studies point to needles as a viable source of EOs. Total qualitative-quantitative profiles of individual volatile organic compounds (VOCs) of EOs extracted from berries, old and young needles, gathered from the same locality, were obtained by GC–MS and GC–FID analyses. Moreover, qualitative-quantitative differences were determined among particular EOs within two subsequent years. Generally, VOC profiles of EOs were mainly represented by monoterpenes, sesquiterpenes and their oxygenated derivatives. Depending on the harvest year, α-pinene (27.70–35.42 %) was the most abundant VOC in juniper berry EOs, followed by germacrene D, sabinene, myrcene, germacrene B and β-pinene. Overall, needle EOs were primarily characterised by sabinene, α-pinene, γ-terpinene and terpinen-4-ol, but with an intense dependence on the needle age and harvest year. β-Ylangene and α-cubebene were specific to berry EOs, whereas trans-2-hexenal was specific to needle EOs. Discriminant analysis achieved 100 % accuracy of correctly classified EOs according to the raw material and harvest year. α-Cubebene, germacrene B, γ-muurolene, one unknown compound and trans-2-hexenal were identified as the most significant for discrimination according to the source, while juniper camphort, cis-2-p-menthen-1-ol, terpinen-4-ol and β-elemene played dominant roles in discrimination according to the harvest year.