Extraction of Santolina insularis essential oil by supercritical carbon dioxide:: influence of some process parameters and biological activity

Santolina insularis was used to obtain its essential oil by means of supercritical fluid extraction with carbon dioxide, CO2. The choice of the proper value of CO2 density is the crucial point influencing solvent power and selectivity, the main factors determining oil composition. In circuit to obtain a pure essential oil deprived of cuticular waxes, the extraction products were fractionated in two separators operated in series. A good process performance was obtained working at 90 bar and 50 degreesC in the extraction vessel, at 90 bar and -12 degreesC in the first separator and at 20 bar and 15 degreesC in the second separator. The extraction time proved to be another parameter that determines the composition of the essential oil extracted. Indeed, lower molecular weight and less polar compounds were more readily extracted, since the other families of compounds exhibit higher diffusion times. The oil extracted also contained small quantities of water. The water yield was measured and the possible role of water in the extraction process is discussed. A comparison with the oil obtained by hydrodistillation is also given. Finally, the cytotoxic and antimicrobial activity of the various extracts has been assayed. Copyright (C) 2001 John Wiley & Sons, Ltd.