GC-FID/MS screening of supercritical CO2 extracts of peels from Citrus aurantium L.

The peels of Citrus aurantium L. from Dubrovnik region (south Croatia) were extracted first time by supercritical CO2 (SC-CO2) at 40 °C and 10 MPa at 1.76 kg/h to obtain enriched extracts in comparison with simple pressing of the peels. The extracts were analyzed in detail by gas chromatography and mass spectrometry (GC-FID/MS). Seven volatiles were found with simple pressing, with monoterpene limonene as predominant (88.2 %), while other abundant compounds were β-myrcene (1.7 %), linalyl acetate (1.8 %) and 7-methoxy-8-(2-formyl-2- methylpropyl)coumarin (2.8 %). SC-CO2 extraction provided enriched profiles of volatiles and semi-volatiles with respect to oxygenated monoterepene and sesquiterpene as well as coumarin derivatives for all the samples due to the high penetration inside plant materials and solvent power of SC-CO2 that is known for SFE method [1, 2]. Monoterpene hydrocarbons dominated in all the samples, with limonene as predominant compound (54.3 %). The principal oxygenated monoterpenes were linalool (5.9 %), α-terpineol (0.7 %), linalyl acetate (5.0 %), geranyl acetate (0.4 %), (Z)-citral (0.5 %) and (E)-citral (0.7 %). Coumarin derivatives were identified by SC-CO2 extraction among significant compounds. Isogeijerin (7-methoxy-6-(3-methyl-2-oxobutyl)-2H-1- benzopyran-2-one) dominated (11.2 %). Scoparone (6, 7-dimethoxycoumarin) was present with lower abundance (0.1 %). As well as bergapten (0.7 %), osthole (7-methoxy-8-(3-methyl-2- butenyl)coumarin ; 0.9 %) and 7-methoxy-8-(2-formylpropyl)coumarin (0.2 %).