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Abstract
Isolation of volatile concentrate from the dried leaves of Aloysia triphylla (L'Herit.) Britton (lemon verbena) and the dried flowers of Calendula officinalis L. were obtained by supercritical extraction with CO2. To obtain a pure volatile extract devoid of cuticular waxes, the extraction products were fractionated in two separators operating in series. A good extraction process was obtained operating at 90 bar and 50°C in the extraction vessel, at 90 bar and at −5°C in the first separator and at a pressure between 20 and 15 bar and temperatures in the range (10–20°C) in the second one.
The composition of the volatile concentrate has been analyzed by GC/MS. The volatile concentrate of A. triphylla was found to contain: phytol (11.6%), spathulenol (7.1%), caryophyllene oxide (5.6%), methyl 9,12,15-octadecatrienoate (5.6%) and α-curcumene (4.6%). The volatile concentrate of C. officinalis was found to consist of: methyl hexadecanoate (23.8%), methyllinoleate (18.6%), methyl 9,12,15-octadecatrienoate (17.2%), methyloctadecanoate (4.8%), methyl tetradecanoate (4.6%), γ-cadinene and cubenol (4.0%), ω-cadinene (3.2%), α-cadinol (1.8%) and oplopanone (1.3%). To complete the investigation, a comparison with the hydrodistilled oil has been carried out.
On the exhausted matrix a further extraction at higher pressure (320 bar) and 50°C with a single separator was performed for the extraction of lutein from Calendula flowers, the amount of lutein obtained was determined by spectrophotometric measurements.