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 superc ritical fluid extraction with carbon dioxide, CO2. The choice of the proper value of CO2 density is the crucial point influencing solvent power and se lectivity, the main factors determining oil composition. In circuit to obta in a pure essential oil deprived of cuticular waxes, the extraction product s were fractionated in two separators operated in series. A good process pe rformance 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 anot her parameter that determines the composition of the essential oil extracte d. Indeed, lower molecular weight and less polar compounds were more readil y extracted, since the other families of compounds exhibit higher diffusion times. The oil extracted also contained small quantities of water. The wat er yield was measured and the possible role of water in the extraction proc ess is discussed. A comparison with the oil obtained by hydrodistillation i s also given. Finally, the cytotoxic and antimicrobial activity of the vari ous extracts has been assayed. Copyright (C) 2001 John Wiley & Sons, Ltd.