CHEMICAL COMPOSITION OF THE ESSENTIAL OILS FROM THYMUS MASTICHINA OVER A DAY PERIOD

The content of this article has previously been published in Part I of the International Conference on Medicinal and Aromatic Plants proceedings, Acta Horticulturae number 576.

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In the present work, the aerial parts of T. mastichina maintained in pots, on a sandy soil and fertilized every fifteen days with a solution 1:3:1 (N:P:K) and 0.4 % Mg, were collected over a day period, during the flowering phase.
The oils were isolated from both the fresh leaves and the fresh flowers by hydrodistillation and analyzed by GC and GC/MS. The highest oil yields were obtained from the flowers, the highest ones (2.0 % and 2.2 %, v/w) being ob-served when the flowers were collected at 12 h and 17 h, respectively.
The major component of the essential oils was 1,8-cineole, present in higher amounts in the leaf oils than in the flower oils.
The minimal percentages detected in the leaf and the flower oils were 50.2 % and 46.7 %, respectively, observed at 23 h, while the maxi-mal ones were 61.0 % and 50.2 %, at 12 h.
Camphor, -terpineol+borneol and terpinen-4-ol were also in higher amounts in the leaf oils than in the flower oils.
In both the leaf and the flower oils, more elevated concentrations of -terpineol+borneol were detected at 23 h (9.7 % and 8.2 %, respectively). -Pinene, camphene, sabinene and -pinene were the monoterpene hydrocarbons whose concentrations exceeded 1.0 %. The flower oils were richer in -pinene, sabinene, -pinene and myrcene than the leaf oils.
The most im-portant quantitative difference was observed for myrcene.
The concentration of this compound was ten times superior in the flower oils relative to the leaf oils.
Higher levels of p-cymene were observed in the leaf oils than in the flower oils.
In almost all samples, elemol was the sole sesquiterpene whose concentration exceeded 1.0 %.