ESSENTIAL OILS FROM JUNIPERUS PSEUDOSABINA: OPTIMIZING EXTRACTION CONDITIONS AND EVALUATING THEIR BIOLOGICAL ACTIVITY

Introduction. The genus Juniperus ranks second in prevalence among coniferous plants and is the largest in the family Cupressaceae. Many juni-perus species have long been used in folk medicine, as well as in the food and perfume industries, due to their high content of essential oils, which exhibit a broad spectrum of biological activity. However, only one study has been devoted to the essential oils of Juniperus pseudosabina from various populations in Kazakhstan, China, and Mongolia, and no data on their biological activity were presented. In the present work, the component composi-tion and biological activity of the essential oil of Juniperus pseudosabina from the flora of Buryatia are reported for the first time. The aim of this work was to select optimal parameters for the extraction of essential oils from the woody greenery of Juniperus pseudosabina and to determine their biological activity. Material and Methods. The woody greenery of J. pseudosabina were collected in September 2025 in the Tunkinsky District of the Republic of Burya-tia. Essential oils were isolated by hydrodistillation under varying extraction durations (1, 2, 3, 4, and 5 hours) and degrees of raw material comminu-tion (whole, 7 mm, 5 mm, 3 mm, and 0.5 mm). The qualitative composition and quantitative content of components were determined by GC-MS, an-tibacterial activity was assessed using the disk-diffusion method and the serial dilution method, and antiradical activity was evaluated using the DPPH test. Results. Hydrodistillation revealed a dependence of the essential oil yield from J. pseudosabina woody greens on technological parameters: at the same degree of grinding (0.5 mm), the maximum yield was recorded after 3 h of extraction (11.9±0.5%); an increase in particle size (3–7 mm and in-tact raw material) at the same extraction time was accompanied by a decrease in yield. GC-MS analysis identified up to 58 compounds of terpene na-ture, with the group composition characterized by the predominance of sesquiterpenes. Comparative analysis showed that the qualitative composition was close to literature data for samples from adjacent regions; however, quantitative ratios varied depending on extraction time and degree of grind-ing. The essential oils exhibited low antiradical activity in the DPPH test, which is generally characteristic of essential oils of other Juniperus species and varies considerably depending on the juniper species, chemotype, as well as experimental conditions (free radical concentration, incubation time, and solvent). Antimicrobial screening demonstrated selective action: gram-positive bacteria (S. pyogenes, S. aureus) and, to a lesser extent, the fungus C. albicans were susceptible, while gram-negative strains (E. coli, P. aeruginosa, K. pneumoniae) were resistant. Conclusions. It was shown that the optimal parameters for the isolation of essential oils from the woody greenery of Juniperus pseudosabina by hy-drodistillation are: particle size – 0.5 mm, and extraction duration – 3 hours. For the first time, the qualitative composition and quantitative content of components of the essential oils from the woody greenery of J. pseudosabina from the flora of Buryatia have been studied. It was established that the major components are α-pinene, sabinene, 4-hydroxygermacra-1(10),5-diene, elemol, α-cadinol, and δ-cadinene. It was found that the essential oils exhibit low antiradical activity and selective antibacterial activity against Gram-positive bacteria and fungi. The data obtained indicate the promise of further study of this species and may also characterize J. pseudosabina as a source of valuable essential oils.