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

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, -10degreesC), thereby allowing pure essential oils to be collected in the second separator (15 bar, 10degreesC). An extraction carried out on a charge of leaves, at 90 bar and 50degreesC, 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%), alpha-pinene (10.5%) and beta-myrcene (8.1%). At a constant temperature of 50degreesC, 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 delta-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 activity 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. Copyright (C) 2003 John Wiley Sons, Ltd.