Chemical composition of essential oil of common juniper (Juniperus communis L.) branches from Estonia

Abstract

For the treatment of the urinary system and kidney diseases, common juniper (Juniperus communis L.) fruits are widely used. This raw material is included in the European Pharmacopoeia (Ph.Eur.) and is one of the most popular kinds of official medicinal plant material with diuretic and uroantiseptic activity. However, the main biomass of bushes consists of green branches, which also contain a significant amount of essential oil that can be used in pharmaceutical practice. The branches become waste during bush cutting. So, it is advisable to investigate the chemical composition of essential oil isolated from common juniper branches from different regions of Estonia to prove the possibility of using this essential oil and branches in pharmaceutical practice.
 Aim. Therefore, the aim of the research was to determine the chemical composition of essential oil from common juniper (J. communis L.) branches from Estonia.
 Materials and Methods. The branches of juniper shrubs were collected in the summer months from 27 different habitats in Estonia. The essential oil was isolated from fresh juniper branches by the modified distillation method described in the European Pharmacopoeia monograph of Juniperi pseudo-fructus. GC/MS analysis was carried out using an Agilent 5975 Series MSDMSD, Agilent7890A GC (Agilent Technologies, Inc.) with two detectors (MSMS and FID) on a fused silica capillary column (30 m x 0.25 mm) with a bonded stationary phase: poly(5 %-diphenyl-95 %-dimethyl)siloxane (DB-5). The carrier gas was helium with a split ratio of 1:30, and the flow rate of 1.3 mL/min was applied. The temperature program was from 50°–240˚C at 2˚C/min and the injector temperature was 300˚C. The MS detector was operated in the EIEI mode of 70 eV and at a scan rate of 2 scans/s with a mass acquisition range of 20–400 u.
 Research results. The average amount of juniper essential oil in branches extracted during distillation using the Ph. Eur. method was 0.23±0.04 ml. 103 substances were identified in 27 different samples of juniper branches and quantified by the GC/MS method. The dominant components of Estonian common juniper essential oil are α-pinene (37.5-69.3 %), pinene, sabinene, β-myrcene and β-phellandrene. The juniper essential oils from Estonian raw materials were compared with Serbian, Iran, Portuguese, French and Greek ones. It was established that the common juniper growing in Estonia belongs to the α-pinene chemotype.
 Conclusions. Common juniper growing in Estonia belongs to the α-pinene chemotype. 103 substances were identified, and their assay was established in 27 different samples of juniper branches. The dominant components of Estonian common juniper essential oil are α-pinene (37.5-69.3 %), so it could be used as a source of a-pinene for the pharmaceutical industry.
 As the essential oils of common juniper branches didn’t meet all the requirements of the European Pharmacopoeia for juniper berries oil, so separate regulatory documentation must be developed for the essential oil from the branches