Agronomic evaluation and identification of Lippia alba chemotypes from Distrito Federal, Brazil

Agronomic evaluation and identification of Lippia alba chemotypes from Distrito Federal, Brazil The main objective of this work was to describe the essential oil profile of 16 genotypes of Lippia alba from the germplasm collection of the Universidade de Bras lia and to analyze its potential of production. A field assay was carried out in the rural area of Distrito Federal and the following parameters were analyzed: flowering period, growing habit, foliar area, length of the main branch, fresh and dry weight of the biomass (leaves and branches), essential oil content and profile of the constituent volatile oils. Essential oil was extracted using a modified Clevenger apparatus and the constituent volatile oils were analyzed by gas chromatography and GC/MS. The experimental design was randomized blocks with three plants per plot. The following chemotypes were reported: citral-limonene, citral-myrcene, limonene-carvone, citral, linalool, myrcene and linalool-limonene. Higher levels of linalool were found in genotype L. 16 (89.8%); myrcene in L. 37 (47.6%); limonene in L. 27 (36.0%); carvone in L. 27 (46.9%) and citral in L. 17 (56.7%). The genotypes with the highest leaf area and leaf length of the main branch seem to be correlated with the best yield of essential oil and the higher level of linalool. The yield of essential oil was inversely proportional to the dry weight of biomass. The accessions which presented the highest average yield of the major essential constituent oils were: L. 16 (0.77 g pl(-1)) as a source of raw material for linalool production; L. 17 (0.17 g pl(-1)) as source of myrcene; L. 27 as source of limonene (0.17 g pl(-1)) and carvone (0.21 g pl(-1)); and L. 38 (0.24 g pl(-1)) as a citral source.