Essential oil composition of Thymus lotocephallus G.!Lopez & R.!Morales, collected during flowering and vegetative phases

The aerial parts of Thymus lotocephalus were collected during the flowering and vegetative phases of the plant in the Algarve, Portugal. The oils were isolated by hydrodistillation and distillation-extraction and analysed by GC and GC-MS. The oil isolated from the flowers was obtained in a yield of 0.9%, whereas those isolated from the leaves during flowering and vegetative phases showed lower yields, 0.7% and 0.2% (v/w), respectively. The oils isolated from both the flowers and the leaves were dominated by the oxygen-containing monoterpenes (57-64%). The monoterpene hydrocarbons (11-22%) and the oxygen-containing sesquiterpenes (7-14%) were the two other main fractions of these oils. 1,8-Cineole (10-19%), linalyl acetate (6-14%) and linalol (4-12%) were the main components of all the oils studied. Intermedeol (2-4%), beta -caryophyllene oxide (2-3%) and viridiflorol (1-3%) were the main components of the oxygen-containing sesquiterpene fraction. The diterpene abietatriene was present in trace amounts (<0.05%) in all the oils. Depending on the plant part studied and on the isolation procedure used, these oils can be characterized either by 1,8-cineole/linalol/linalyl acetate or 1,8-cineole type. Copyright (C) 2001 John Wiley & Sons, Ltd.