Determination of chemical constituents of leaf and stem essential oils of Artemisia monosperma from central Saudi Arabia.

The leaf and stem essential oils of Artemisia monosperma from the desert region of central Saudi Arabia were analysed by gas chromatography-based techniques (GC-FID, GC-MS, Co-GC, LRI determination, database and literature search) using polar as well as non-polar columns, which resulted in the identification of 130 components, of which 81 were common to both oils. In the leaf oil 120 compounds were identified, while 91 were identified in the stem oil accounting for 98.4% and 99.7% of the oil composition, respectively. The major constituents of the leaf oil were beta-pinene (50.3%), a-terpinolene (10.0%), limonene (5.4%) and a-pinene (4.6%), while the major constituents of the stem oil were beta-pinene (36.7%), a-terpinolene (6.4%), limonene (4.8%), beta-maaliene (3.7%), shyobunone (3.2%) and a-pinene (3.1%). The two oils showed an important qualitative similarity. However, some specific constituents (39 in the leaf oil and 10 in the stem oil) allow differentiation of the two essential oils.