Yield and chemical variability of the essential oil isolated from aerial parts of wild Origanum compactum Benth. From Moroccan Western Rif

The objective was to investigate the yield and the chemical composition of O. compactum essential oil isolated from plants collected in the North West of Morocco (Rif). Thirty six plant samples of native populations of O. compactum were collected during flowering. Essential oil yields varied drastically from 0.31% to 2.44% of dry matter. The highest yields were obtained from plants harvested in the eastern part of Tetouan province, (semi-arid climate). No direct correlation was observed between the yield and the altitude of the harvest areas, the soil pH and the contents of OM, K2O or P2O5. Analysis of the oil samples was carried out by GC, GC-MS and 13C NMR. According to statistical analysis, three groups were identified, dominated by carvacrol, thymol and carvacrol/thymol, respectively. These results may bring valuable information for the selection of wild plants to initiate the domestication of O. compactum in Morocco, species threatened by overharvesting.