Comparison of essential oils from Cistus species growing in Sardinia.

Cistus genus is present in Sardinia with large populations of C. monspeliensis, C. salvifolius, C. creticus subsp. eriocephalus and few stations of C. albidus, C. creticus subsp. creticus and C. creticus subsp. corsicus. No chemical studies are currently being carried on Cistus species of Sardinia. The essential oils have shown six different profiles. C. creticus subsp. eriocephalus showed a high amount of manoyl oxide and its isomer (70%). C. salvifolius has pointed out the group of labdans, (20%); another consistent percentage is made of perfumed molecules as ionone and its derivate. Several linear hydrocarbons were produced by C. monspeliensis, and the heneicosane was the most represented element. In C. albidus no labdane-type diterpenes were identified. Analysis of C. creticus subsp creticus revealed several oxygenated sesquiterpenes and labdane-type diterpenes, especially manoyl oxide. C. creticus subsp. corsicus was qualitatively very similar to C. creticus subsp. creticus, notably concerning the labdane-type compounds.