Citrus essential oils and main terpenes: chemical composition and good litholytic activity on gallstones

We studied the gallstone dissolving capacity of Moroccan citrus (C) essential oils; C. clementina, C. aurantium, C. sinensis and C. paradisi. Their litholytic activity was compared to that of their main constituents revealed by a gas chromatography-mass spectrometry (GC–MS) analysis; limonene, linalool and γ-terpinene and to the Methyl tertbutyl ether (MTBE) standard as well. Gallstone sample was classified as a cholesterol type after a quantification analysis, using UV-spectrophotometer. The hydrocarbon compounds predominated the chemical composition of the oils, limonene was the commonly major identified compound, representing between 72.06 and 88.49 %. The citrus essential oils caused a deterioration in the morphological appearance of gallstone samples. The C. sinensis essential oil manifested with remarkable litholytic activity after a day of incubation, reached to a dissolution capacity of 95.78 ± 0.49 %, the same for C. clementina with 94.81 ± 1.30 % and C. aurantium with 92.99 ± 2.04 %. These oils were more effective than MTBE standard. In last position, C. paradisi essential oil exhibited the less high dissolution of 87.68 ± 1.82 %, comparing with other oils. Linalool showed a good litholytic activity, better than that of MTBE and similar to that of limonene. Therefore, in addition to limonene role, also the other constituents may have, as a natural mixture, an important additive effect in the gallstone dissolution of each essential oil.