The bark essential oil composition and chemotaxonomical appraisal of Cedrelopsis grevei H. Baillon from Madagascar

Cedrelopsis grevei is an aromatic and endemic tree of Madagascar. Its essential oil, resulting from its bark, and known under the name katrafay oil, is used in Madagascar in traditional medicine and in aromatherapy in the areas of the North. The chemical composition of this oil shows a great variability. This work proposed to study some determinants of this variability. Sampling was carried out tree by tree, in six representative sites of the distribution area of the species, followed by distillation and analysis by GC-MS. Twenty one samples were thus analyzed and 71 molecules were identified in at least one sample. A principal components analysis was performed considering the thirteen principal compounds identified in these essential oils. Four chemical patterns were distinguished. The first is characterized by eudesmane skeletons, mainly represented by selinenes (3.417.2%) and eudesmols (9.9-37.8% and 0-11.1% for the [alpha]- and [gamma]- isomers, respectively); the second is rich in a-pinene (2.1-30.0%) and copaborneol (4.7-20.0%); the third is dominated by [alpha]-copaene (5.9-11.8%) and ishwarane (13.7-22.1%), and the last by cadinane skeletons (cadinenes 0.5-35.2%, T-muurolol 0-11.8% and [alpha]-cadinol 0-6.7%). Variable amounts of [alpha]-bisabolol were found in samples belonging to these four groups. Our study indicates a linkage between the zone of gathering and the essential oil chemical composition. There was not much variability between trees in the same zone, but there were big differences from one zone to another. These results make it possible to propose methods for sustainable collection and durable management of the species.