Chemical variations of the essential oils in flower heads of Chrysanthemum indicum L. from China

The volatile compositions of hydrodistilled essential oils in the flower heads of Chrysanthemum indicum L. from eight populations in China were analyzed by GC/MS. A total of 169 compounds representing 88.79-99.53% of the oils were identified, and some remarkable differences were found in the constituent percentages of the eight populations. The predominant components of the essential oils were 1,8-cineole (0.62-7.34%), (+)-(1R,4R)-camphor (0.17-27.56%), caryophyllene oxide (0.54-5.8%), β-phellandrene (0.72-1.87%), (-)-(1S,2R,4S)-borneol acetate (0.33-8.46%), 2-methyl-6-(p-tolyl)hept-2-ene (0.3-8.6%), 4,6,6-trimethylbicyclo[3.1.1]hept-3-en-2-yl acetate (0.17-26.48%), and hexadecanoic acid (0.72-15.97%). The chemotaxonomic value of the essential-oil compositions was discussed according to the results of cluster analysis (CA) and principal-component analysis (PCA). The eight populations were divided into five groups as different chemotypes (Groups A-E), and the scores together with the loadings revealed clearly different chemical properties of each population. In conclusion, GC/MS in combination with chemometric techniques provided a flexible and reliable method for characterizing the essential oils of different populations of C. indicum L.