Extraction of Juniperus oxycedrus ssp. oxycedrus essential oil by supercritical carbon dioxide: influence of some process parameters and biological activity

Abstract

Supercritical carbon dioxide extraction of the leaves and berries of Juniperus oxycedrus L. ssp. oxycedrus, coupled with a two-stage separation, allowed the entrapment of cuticular waxes in the first separator (90 bar, −10°C), thereby allowing pure essential oils to be collected in the second separator (15 bar, 10°C). An extraction carried out on a charge of leaves, at 90 bar and 50°C, gave a yield of 0.8% (w/w) with respect to the charged material, of an oil whose major constituents were germacrene D (15.9%), manoyl oxide (10.2%) and 1-epicubenol (5.4%). The berry oil obtained, at the same pressure and temperature as those for the leaves, gave a yield of 0.45% (w/w) and was composed chiefly of germacrene D (13.8%), α-pinene (10.5%) and β-myrcene (8.1%). At a constant temperature of 50°C, different extraction pressures (80, 90 and 100 bar) were tested in order to obtain the juniper wood essential oil. The extraction yield depended strongly on the extraction pressure, reaching a maximum of 14.7% (w/w) at 100 bar. The main constituents in the extract were δ-cadinene, calamenene, cubenol and 1-epi-cubenol. Hydrodistillation of the wood of J. oxycedrus gave a yield of 11.0% (w/w) of essential oil, with a reduced level of sesquiterpene hydrocarbons and an enhanced amount of oxygenated sesquiterpenes, with respect to the oil obtained by supercritical carbon dioxide extraction. The extracts obtained at different pressures were tested for cytotoxicity, antiviral and antimicrobial activities. The results showed that the extracts of leaves and berries obtained at 200 bar were cytotoxic against different cell lines used to support virus growth. As far as antiviral activiy is concerned, some of the extracts were active against a single-stranded RNA + virus (Poliovirus-1). When tested for antimicrobial activity, none of the samples were shown to be active.

Leaf Essential Oil of Juniperus oxycedrus L. (Cupressaceae) Harvested in Northern Tunisia: Composition and Intra‐Specific Variability

“…The obtained yields of J. oxycedrus essential oil were generally lower than the yield reported by Salido et al [15] for J. oxycedrus from Spain (0.27%) and that of essential oil from Sardinia (Italy), obtained by supercritical CO 2 distillation [17], and higher than that of essential oil from Sardinia (Italy), obtained by hydrodistillation (0.04%) [18]. Moreover, regarding the differences in the yields of essential oil in relation to the phenological phases of the tree, the highest yields were obtained in the third phase (July 2005), except for Makthar J. oxycedrus essential oil, which showed the maximum yield in the second harvest season.…”

Comparison of supercritical CO2 and hexane extraction of lipids from sorghum distillers grains

“…The solubility of solutes in SC-CO 2 and the selectivity of SC-CO 2 extraction can be modified with changes in the extraction temperature and pressure [7]. SC-CO 2 has been used to extract plant materials, especially lipids [8], essential oils [9][10][11], flavors [12,13] and herbal medicines [14][15][16][17]. Supercritical fluid extraction of different materials has been reviewed by Lang and Wai [18], Meireles and Angela [19], and Wang and Weller [7].…”

New extraction technique for alkaloids

“…Natural products are extracted by conventional methods such as Soxhlet and room temperature solvent extraction, [1][2][3][4][5][6][7] or by ultrasound, [8][9][10][11][12][13][14] microwaves, [15][16][17][18] supercritical solvents [19][20][21][22][23][24][25][26][27][28][29][30] or other methods. [31][32][33][34] In this paper a new method is developed to extract alkaloids, which are among the most important groups of secondary metabolites.…”