An assessment of the behavior of carvacrol – rich wild Lamiaceae species from the eastern Aegean under cultivation in two different environments

Abstract

Essential oil concentration and composition of selected wild biotypes of Coridothymus capitatus, Satureja thymbra, Origanum onites, and Origanum hirtum from the Greek island of Ikaria in the Eastern Aegean were assessed under cultivation in comparison with plants growing in their native environment. Eight biotypes (two from each species) were cultivated under rainfed conditions in two different habitats (Ikaria and Athens) using vegetative propagation material from the native plants. The cultivated plants were harvested for essential oil determination and analysis in the second year from their establishment in the field. In addition, wild plants from the same biotypes growing in their natural habitats in Ikaria were sampled and analyzed for comparative purposes. The values of the essential oil concentration, both under cultivation and under natural conditions, detected in this work for all biotypes and species, were higher than those reported in the existing literature. Carvacrol, p-cymene, γ-terpinene, and caryophyllene were the main constituents of the essential oil in all four species and biotypes. The carvacrol percentages detected in this work were close to the highest values recorded by other investigators for C. capitatus (66.58–77.78%), O. onites (74.86–80.43%) and O. hirtum (72.32–82.61%), but significantly higher than those recorded for S. thymbra (41.71–49.22%). The absence of a significant location effect on oil concentration indicates that the transfer of the biotypes from their native habitats and their cultivation in other environments did not significantly affect this very important trait and, accordingly, the observed high oil concentrations recorded could be ascribed mainly to the local biotypes. There was a tendency for higher values in carvacrol percentage and lower ones for γ-terpinene and p-cymene under cultivation, when compared to the same biotypes growing in their natural habitats. No differences were detected for caryophyllene.