Desorption of lemon peel oil by supercritical carbon dioxide: Deterpenation and psoralens elimination

Citrus peel oils, obtained by cold pressing, contain large quantities of hydrocarbon terpenes and smaller amounts of psoralens. Some of these latter compounds can exhibit phototoxic activity. Desorption of "Eureka" lemon peel oil by supercritical C02 from a polar adsorbent was performed to selectively eliminate hydrocarbon terpenes and psoralens by operating at different C02 densities. The various fractions obtained were analyzed by GC-MS. Four fractions were characterized: terpenic fraction, deterpenated fraction, waxes, and residue. The deterpenated fraction contained about 76% of oxygenated terpenes. All coumarins and psoralens contained in the starting material were concentrated in the waxes and in the residue. Particular attention was dedicated to ascertaining the elimination of bergapten and oxypeucedanin whose photosensitizing activity is well known. © 1994