The essential oils from the leaves of Hypericum perforatum (A) and H. sampsonii (B) were obtained by steam distillation, respectively. The chemical compositions were separated and identified by GC - MS. 71 components were determined and quantified (A and B including 53 and 30 in them, respectively). The relative contents in the essential oils were determined by area normalization. The main compositions are terpenoids (sesquiterpens) and hydrocarbons, The compositions of the essential oil of H.sa...
