The essential oil obtained by steam distillation from leaves of Oonamomi (Xanthium canadense Mill.) has been stadied. The constituents were separated by means of column chromatography and preparative gas chromatography and were identified by GC, MS, IR and NMR.
Twelve terpenoid compounds and sixteen alkane were recognized as the constituents of the essential oil, among which germacrene-D (28.5%), cis-2-hexen-1-ol, limonene, δ-elemene, β-caryophyllene, α-humulene, β-selinene and δ-cadinene were main components.
Two oxygen-containing guaiene compounds were isolated and their respective stractures were assigned to be 6, 11-oxyguaja-4, 9-diene (27) and 4-hydroxyguaja-6 (7), 10 (14) -diene (31) based on the chemical and spectral evidence.