Concentration of Ruta graveolens active compounds using SC-CO2 extraction coupled with fractional separation

Supercritical CO2 (SC-CO2) extraction coupled with fractional separation of the extracts, has been used to concentrate the active principles of Ruta graveolens. Using 250 bar, 40 degrees C for the extraction process and cooling the first separator to -10 degrees C, an efficient extraction and fractionation was obtained. Different particle sizes of the vegetable matter were tested (from 0.20 to 0.80 mm); they indicated that the extraction process was faster when particle size was smaller; i.e., internal mass transfer controlled the process. Fractional separation allowed the selective elimination of cuticular waxes, that represented about 78% w/w of the total extract produced by SC-CO-2 processing. The extract collected in the second separator was concentrated in active compounds up to 87% w/w. For comparison purposes, extraction was also performed using an organic solvent: the extract obtained using ethyl-acetate, contained low percentages of active compounds, mainly due to the co-extraction of large quantities of waxes.