The chemical composition of the aerial part’s essential oil of an unexplored Vernonia species (Asteraceae) collected in Dhofar region, Oman: Vernonia arabica F. G. Davies

The genus Vernonia Schreb., included within the Asteraceae family, has a large geographical distribution. It has a complex nomenclatural history since, up to a couple of decades ago, it included more than 1000 species, but many of them have been recently moved to other genera, such as Lepidaploa, Vernonanthura, and Distephanus, etc. This is the first report regarding the chemical composition of the essential oil from the aerial parts of Vernonia arabica F.G. Davies. Its essential oil (Va) was characterised by oxygenated sesquiterpenes (39.48%), with shyobunol (9.59%) and endo-1-bourbonanol isomers (9.13% and 4.64%, respectively) as main metabolites. The chemical composition of Va was compared with all the other essential oils of plants formerly indicated as Vernonia, before the botanical revision, showing a peculiar chemical profile, very different with respect to all the other taxa, being shyobunol and endo-1-bourbonanol never detected in any formerly Vernonia species.