Yield and Essential Oil Composition of Lippia citriodora H.B.K. Leaves and Flowers in Semi-Arid Conditions.

Lippia citriodora H.B.K is an herbal species which contains several aroma compounds and the leaves of the plant are utilized as a seasoning for food preparations and flavoring beverages. In this study, the essential oil composition of the L. citriodora growing in semi-arid ecological conditions in Diyarbakır Turkey was determined at different plant parts taken from the upper (leaves and flowers), middle (leaves), and lower portions (leaves). The highest essential oil content (3.7 µl/g in w/w) was obtained from the lower part of the plant. The essential oil of L. citriodora was analyzed by GC/MS and GC/FID. Although the major essential oil composition of the oil was obtained as caryophyllene oxide, limonene, geranial, and neral, caryophyllene oxide and limonene showed significant changes with respect to different plant parts. While the rate of caryophyllene oxide gradually decreases from the lower parts of the plant to the upper parts; it was observed that the limonene ratio increases towards the upper parts of the plant. Principal component analysis (PCA) on the basis of the contents of the 31 compounds showed that two principal components had an eigen value greater than 1 and the first principal component explained 80. 39% of the total variation. In addition to the remarkable chemical differences of L. citriodora essential oil regarding the caryophyllene oxide and limonene, the proportion of these compounds has been observed to be significantly higher than the literature values. [ABSTRACT FROM AUTHOR]