Essential oil and bioactivity of two juniper species from Bulgaria and Slovakia

• Published in: Molecules (Basel, Switzerland) Switzerland), 2021-06, Vol.26 (12 p.3659-)
• Main Authors: Jeliazkov, Valtcho D, Cantrell, Charles L., Semerdjieva, Ivanka, Radoukova, Tzenka, Stoyanova, Albena, Maneva, Vasilina, Kacaniova, Miroslava, Astatkie, Tess, Borisova, Daniela, Dincheva, Ivayla, Salamon, Ivan
• Format: Article
• Language: English
• Subjects: acetates; bioactive properties; Bulgaria; chemotypes; dioecy; essential oils; etoposide; hydrodistillation; industry; Juniperus sabina; leaves; Podophyllum hexandrum; sabinene; Slovakia; steam distillation; toxins; wood
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules26123659

Junipers contain natural products, the most important being essential oil (EO) and podophyllo-toxin. The essential oil (EO) of juniper species has wide applications in various products. Podo-phyllotoxin is a toxin currently extracted from the Himalayan mayapple (Podophyllum hexandrum Royle), it is used as a precursor to the commercially available anti-cancer drugs etoposide and teniposide, and it is found in some junipers. The EO profile and podophyllotoxin concentration depend on juniper species, sex (most junipers are dioecious), but may also depend on subspe-cies/chemotype, the environment, the plant part from which it is extracted (leaves, galbuli, or wood), and the extraction procedure. Two separate studies are described here: The objective of the first study was to assess variability in EO profile and podophyllotoxin concentration of Juniperus sabina, and J. excelsa depending on the location and sex of the tree. Overall, the EO of J. sabina (1.98%) was higher than that of J. excelsa (1.16%). The EO content in J. excelsa varied from 0.69 to 1.87%, whereas the EO content in J. sabina was 1.3-2.1%. The main EO constituents of J. excelsa were a-cedrol (29.09-32.5%), a-limonene (24.14-26.36%) and a-pinene (19.71-22.53%), while the ones in J. sabina were sabinene (16.68-30.98%), terpinene-4-ol (9.25-13.63%), myrtenyl acetate (1.32-23.02%), elemol (8.45-13.70%), and a-cadinol (3.47-3.77%). Podophyllotoxin yield from the leaves of eighteen J. sabina accessions was 0.07-0.32% (w/w) while it was not found in J. excelsa accessions. The objective of the second experiment was to assess the effect of EO extraction (hydrodistillation using Clevenger type apparatus vs steam distillation in a semi-commercial facility) on EO profile and bioactivity of J. sabina and J. excelsa. The extraction type did not significantly alter the EO compo-sition. Overall, the EO profile of the two junipers and accessions was quite different and may be of interest to the EO industry utilizing juniper leaf essential oil. However, J. sabina and J. excelsa are protected species and therefore, their natural populations may not be utilized for commercial production of EO of podophyllotoxin. Therefore, it is suggested that breeding and selection programs be developed with the two junipers to identify chemotypes with (1) high EO content and desirable composition (in both junipers), and (2) high concentration of podophyllotoxin in J. sabina. Such chemotypes can be eventually developed into agric