Dry leaves of Menlba piperita L. 'Kliment-63' and 'Zefir' of 1997 crop were used.

The oil yield from 'Zefir' was 0.97% and that from 'Kliment-63' was 0.54%. The oil from 'Zefir' was found to be rich in menthol (46.2-50.2%) and menthyl acetate (16.8-22.5%). In the oil from 'Kliment-63,' the content of these components was lower, while the menthone content was higher (20.0-23.1%).

Mentha rotundifolia leaves were collected in the second week of November 2004 in two localities of Algeria (Rouina: altitude 250 m, Miliana: altitude 780 m) within the region of Ain-Defla located in northern Algeria.

Thirty-nine compounds were identified in leaf oil of sample 1 (Rouina, Algeria), the main one being cis-piperitone oxide. Thirty-nine compounds were identified in leaf oil of sample 2 (Miliana, Algeria). The main one being piperitenone oxide.

The aerial parts of T. chamaedrys were collected at the flowering stage in June 2004 near Corti, Corsica, France and near Oristano, Sardinia, Italy

The Corsican and Sardinian oils of T. chamaedrys investigated in this study were qualitatively similar but they differed by the amount of their major components. The major components were beta-caryophyllene (29.0% and 27.4%, respectively) and germacrene D (19.4% and 13.5%, respectively), followed by alpha-humulene (6.8%) and delta-cadinene (5.4%) in the Corsican oil and by caryophyllene oxide (12.3%) and alpha-humulene (6.5%) in the Sardinian oil. These quantitative differences are also noticeable on the amounts of the different class compounds. Especially, the monoterpene hydrocarbons amounted for 10.3% and 4.1% in Sardinian and Corsican oils respectively and the oxygenated sesquiterpenes amounted for 18.9% and only 7.4% in both oils, respectively. Both oils were qualitatively rather similar in comparison with those reported in the literature from various geographic regions. However, among the 87 components identified in this study, 47 minor components (< 0.6%) reported were identified for the first time in T. chamaedrys oil. This study confirms the quantitative variability of the major components according to the plant origin.

The aerial parts of T. flavum were collected in different periods from December to July 2006, from plants growing along the Ionic coast of Sicily (Italy). LF 1-LF 2-LF 3: represent the composition of leaf oils of plant samples collected in December (vegetative stage), February (pre-flowering stage) and April (budding stage) respectively; FL: flower oil; FR: fruit oil.

Some components, in all investigated plant parts, remained more or less constant during all the different phases of the plant cycle life. Worthy of note, considering the leaf oils, was that beta-pinene, limonene and germacrene D increased in the pre-flowering stage, while a series of esters and alpha-copaene, beta-caryophyllene, viridiflorol, Tmuurolol and phytol increased in the budding stage (LF3); the vegetative stage oil is generally characterized by a rich chemical composition and some constituents such as isoamyl hexanoate, alpha-humulene, bicyclogermacrene, beta-bisabolene and alpha-bisabolol reached their highest levels in this oil. In the flower oil, linalool and 1-octen-3-yl acetate were the main components compared to the amounts found in the other oils. Fruit oil composition was relatively oil poor, with beta-bisabolene, caryophyllene oxide, cadin-4-en-1-ol and phytone as the major constituents.

Plant materials were collected from the following localities in north western Turkey. A = Trabzon: Caykara, Soganli dag on July 28, 1994; B = Bayburt: Caykara, Mohakambo yaylasi on July 25, 1994; C = Trabzon: Koprubasi, Vizara yaylasi on July 20, 1994.

One hundred and four compounds were identified representing 97.5-99.5% of the total components detected in thymol/carvacrol (50.14/10.67%), thymol/linalool (23.14/20.24%) and linalool/alpha-terpinyl acetate/geraniol (21.55/16.70/11.17%) rich oils.