Essential oil composition and biomass productivity of Moroccan endemic Thymus satureioides Coss. Ball. growing in the Agoundis Valley

Abstract

Thymus satureioides Coss. & Ball. (Th. satureioides) is an endemic thyme of Morocco. Thirty two samples of wild T. satureioides were collected from High Atlas Mountains (Valley of Agoundis). The essential oils (EO) isolated by hydrodistillation from the aerial parts were analysed by gas chromatography-mass spectrometry (GC-MS). The yield of EO ranged from 0.2 to 2.3%. Twenty six components, representing more than 95% of the oil, were fully characterized. Borneol was the main constituent. Its proportion varied between 22.7 and 37.5%. Cluster analysis of the identified components grouped the samples into three main chemotypes, borneol/carvacrol (B/Ca), borneol/camphene/carvacrol (B/C/Ca) and borneol/camphene/α-pinene (B/C/P). Other constituents were identified in significant amounts: α-terpineol (3.1 to 10.6%), 3-carene (1.5 to 10.5%) and p-cymene (2.3 to 8%). The fresh matter productivity average of T. satureioides was around 1.3 t/ha, revealing low potential of exploitation for collectors. This study has shown that the thyme growing in the valley of Agoundis is dominated by borneol chemotypes, showing different level of essential oil yield, according to locations and/or genotyes within general low potential of biomass production.