Chemical Composition of the Essential Oils of Achillea millefolium L Isolated by Different Distillation Methods

The chemical composition of the essential oil from flowering tops of Achillea millefolium L. isolated by different distillation methods was Studied. Samples were hydrodistilled with Clevenger-type (HD), simultaneous microdistillation-extraction (SMDE), and microwave (MAHD) apparatus. The yields were 0.46% +/- 0.03 for the HD and 0.48% +/- 0.03 for the MAHD (v/w, volume/dry weight). The oils were analyzed by GC and GC/MS and a total of 58 Components were detected. The major compounds in the oils were 1,8-cineole (10.4-17.2%), sabinene (11.6-14.6%), alpha-terpineol (4.4-5.2%), terpinen-4-ol (2.4-5.7%), and, among sesquiterpenes, gamma-eudesmol (8.7-17.9%) and 6S,7R-bisabolone (4.4-14.9%). From a qualitative point of view, no relevant differences between the different methods of isolation were observed, while statistically significant differences on relative percentage were noticed. Oils obtained by HD showed a higher amount of monoterpenoid compounds (69.2%), while L-SMDE, H-SMDE and MAHD were richer in sesquiterpenes (47.9%, 42.7% and 47.6%, respectively).