Selection of genotypes (citral chemotype) of Lippia alba (Mill.) N. E. Brown regarding seasonal stability of the essential oils chemical profile

Abstract The Lippia alba essential oil has been used for the preparation of cosmetics, which makes important the search for a plant that presents chemical and sensorial properties with greater stability under varying environmental conditions. In this context, the objective of this work was to identify genotypes of L . alba that are stable regarding to essential oil profile in two seasons. For this purpose, we extracted by hydrodistillation and analyzed by GC-FID and GC–MS the essential oils eight L . alba genotypes from plants collected in the summer and winter, to estimate the variation of the metabolites between and within genotypes. Afterwards, the data on geranial and neral concentrations were submitted to analysis of variance (ANOVA) and testing of the means. Then the metabolites data were submitted to the t -test at 5% probability, to compare the two seasons and submitted to cluster analysis by UPGMA. We formulated an index to assess the chemical profile stability according to the genotype, called the Genotype Chemical Profile Stability Index (GCPSI), based on the production of the metabolites between the seasons. All told, 63 metabolites were identified in the essential oil of the genotypes, of which 31 were listed and used as the data for calculating GCPSI. The environment (season) had a stronger influence on the number of metabolites than the total quality of the essential oil. Citral and its isomers geranial and neral were stable during the seasons. In general, the essential oil chemical profile was grouped according to the season. The lowest estimated GCPSI was 84.00% (genotype UFRRJ ECB011) and the highest was 95.40% (UFRRJ ECB005). Of the genotypes evaluated, UFRRJ ECB005 was the most chemically stable. Therefore, we recommend that it be studied regarding its productive potential.