New trans–b–bergamotene derivatives in the root and the flower essential oils of Cyanthillium cinereum (L.) H. Rob. from C^ote d’Ivoire
Résumé
Root and flower essential oils of Cyanthillium cinereum (L.) H. Rob.
(Synonym Vernonia cinerea (L.) Less.) (Asteraceae) collected in
Southern C^ote d’Ivoire was investigated using a combination of
chromatographic and spectroscopic techniques. The root oil composition
was dominated by trans–b–bergamotene (20.7%),
b–elemene (19.0%), cyperene (10.6%), germacrene A (7.1%)
and b–pinene (3.8%), whereas c–humulene (31.0%), (E)–b–
caryophyllene (17.0%), trans–b–bergamotene (7.7%), b–pinene
(7.5%) and (E)–b–farnesene (6.0%) were the major components
of flower oil. Two new compounds bearing the trans–b–
bergamotene framework were identified: trans–b–bergamotenone
and (E)–trans–b–bergamotenol.