Oil yield and composition of Juniperus oxycedrus L. from Bulgaria and Serbia

Abstract

Juniperus oxycedrus L. (Cupressaceae) is widely distributed in countries with a Mediterranean climate. The species is known for its large morphological and chemical variation and its debatable taxonomic status. The objective was to compare the essential oil content and composition of J. oxycedrus plants from Bulgaria and Serbia, and secondly, to quantify morphological variations of leaves. Тhe essential oil content in dried juniper leaves varied from 0.059% (Кopaonik, Serbia) to 0.240% (Markovo, Bulgaria). Around 40 EO constituents were identified, belonging to the groups of monoterpenes, sesquiterpenes, diterpenes, and phenylpropanoids. The monoterpene hydrocarbons and oxygenated monoterpenes were the predominant groups of compounds representing 36.8-66.2% of the total oil, with α-pinene, limonene, sabinene,
β-pinene, β-myrcene being the major constituents of this group. Overall, α-pinene was the major oil constituent in plants from all locations. The second largest group was the one of sesquiterpenes (sesquiterpene hydrocarbons, oxygenated sesquiterpenes), ranging from 19.3 tо 33.6%. There was no significant difference between the mean leaf width of the six combinations of location and tree sex, and the overall mean width was 1.24 mm. However, there was a significant difference between the mean leaf lengths. This study contradicts recent reports that the European populations of J. oxycedrus east of Italy belong to a newly identified species J. deltoides. The same reports claimed that ”the leaf oil of J. deltoides was lower in α-pinene and higher in limonene compared to J. oxycedrus”. In this study, none of the studied populations had a higher concentration of limonene than that of α-pinene. Therefore, this study demonstrated that the flora of the two countries includes indeed J. oxycedrus.