Abstract
Little is known about the immunomodulatory activity of essential oils isolated from Juniperus species. Thus, we isolated essential oils from the cones and leaves of eight juniper species found in Montana and in Kazakhstan, including J. horizontalis, J. scopolorum, J. communis, J. seravschanica, J. sabina, J. pseudosabina, J. pseudosabina subsp. turkestanica, and J. sibirica. We report here the chemical composition and innate immunomodulatory activity of these essential oils. Compositional analysis of the 16 samples of Juniper essential oils revealed similarities and differences between our analyses and those previously reported for essential oils from this species. Our studies represent the first analysis of essential oils isolated from the cones of four of these Juniper species. Several essential oil samples contained high levels of cedrol, which was fairly unique to three Juniper species from Kazakhstan. We found that these essential oils and pure (+)-cedrol induced intracellular Ca2+ mobilization in human neutrophils. Furthermore, pretreatment of human neutrophils and N-formyl peptide receptor 1 and 2 (FPR1 and FPR2) transfected HL60 cells with these essential oils or (+)-cedrol inhibited agonist-induced Ca2+ mobilization, suggesting these responses were desensitized by this pretreatment. In support of this conclusion, pretreatment with essential oils from J. seravschanica cones (containing 16.8% cedrol) or pure (+)-cedrol inhibited human neutrophil chemotaxis to N-formyl peptide. Finally, reverse pharmacophore mapping predicted several potential kinase targets for cedrol. Thus, our studies have identified cedrol as a novel neutrophil agonist that can desensitize cells to subsequent stimulation by N-formyl peptide.
Highlights
The genus Juniperus L. consists of 75 species, which grow mainly in the northern hemisphere [1]
Compositional analysis of 16 essential oils isolated from Juniper plants revealed similarities and differences between our analyses and those previous reported for essential oils from this species
Several of the essential oil samples from Juniper collected in Kazakhstan but not in Montana contained high levels of cedrol, which was fairly unique among the samples and was enriched in JSE, JSA, and JPS
Summary
The genus Juniperus L. consists of 75 species, which grow mainly in the northern hemisphere [1]. Juniperus is one of the main genera of the Cupressaceae family [2], and according to the generally accepted classification, the genus is divided into three sections distributed throughout the world [1,3,4]. These evergreen coniferous trees or shrubs thrive under a variety of environmental conditions. Among the least studied Juniperus are those growing in Kazakhstan. In Kazakhstan, the local names for Juniperus species are “arsha” (in Kazakh) and “mojjevelnik” (in Russian) [9,10]. As in Kazakhstan, a large part of Montana is occupied by steppes
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