Chemical variation in the essential oil ofEphedra sinica from Northeastern China

Hydro-distillated volatile oils of Ephedra sinica Stapf. from six populations of Inner Mongolia in Northeastern China were analyzed by using GC/MS. Ninety-nine compounds were identified in the oils and a relatively high variation in their contents was found. The main constituents of the essential oils were α-terpineol (19.28–52.23%), p-vinylanisole (0.59–11.64%), 3-methyl-2-buten-1-ol (0–5.44%), tetramethylpyrazine (0.63–8.99%), terpine-4-ol (1.17–4.37%), α-linalool (1.62–5.15%), phytol (1.24–15.73%), γ-eudesmol (0–7.77%), and eudesm-7(11)-en-4-ol (0.41–6.13). Six populations were divided into two chemotypes based on cluster analysis and principal component analysis (PCA); one rich in α-terpineol and p-vinylanisole, and the other rich in phytol, γ-eudesmol, and eudesm-7(11)-en-4-ol.