Essential oil constituents of Eclipta prostrata (L.) L. and Vernonia amygdalina Delile.

The chemical composition of the essential oils from the leaves and stem bark of Eclipta prostrata (L.) L. and the aerial parts of Vernonia amygdalina Delile (Asteraceae) have been analyzed by capillary gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The investigation led to the identification of 33 and 30 compounds in the oils of the leaves and stem of E. prostrate, respectively, and 40 compounds in the oil of V. amygdalina. While the oil of the leaves of E. prostrata was highly dominated by sesquiterpenoids (89.3%), the stem bark was comprised of sesquiteprenoids (47.7%), straight chain hydrocarbons (25.6%) and monoterpenoids (11.1%). The main constituents of both oils were P-caryophyllene (47.7% and 15.9%) and a-humulene (31.8 and 12.9%) in the leaves and stem, respectively. In addition, (E)-beta-farnesene (10.0%) was also identified in significant amount in the stem bark. On the other hand, the major component of V. amygdalina oil was alpha-muurolol (45.7%).