Essential oil variation in Lippia glandulosa Schauer

The oils of 14 samples of Lippia glandulosa collected in the Lavrado area, Roraima state, North Brazil, were obtained by hydrodistillation and analyzed by GC and GC/MS. Two chemical groups were characterized in the oils, one which was rich in thymol (46.3-78.1%), and another containing beta-caryophyllene (17.3-59.4%) as the major component. In the first group the compounds p-cyrnene (5.1-7.2%) and beta-caryophyllene (4.1-9.2%) have been associated to thymol in six of the analyzed oil samples. On the other hand, the second group showed variable association with (E)-nerolidol (0.7-23.6%), trans-alpha-bergamotene (0.2-19.3%), alpha-alaskene (3.4-16.0%), alpha-pinene (1.2-7.8%), alpha-humulene (2.6-6.0%), caryophyllene oxide (1.9-6.0%) and linalool (0.9-5.0%), in the other eight oil samples, justifying the field observation concerning the plant scent variability at the same collection site and the chemical composition differentiation observed to L. glandulosa.