Chemical diversity and influence of plant age on the essential oil from Lippia sidoides Cham. germplasm

Pepper-rosmarin (Lippia sidoides Cham.) is a medicinal and aromatic species that is native to northeastern Brazil and has pronounced pharmacological, agronomical and economic importance. The objective of this study was to evaluate the chemical diversity of L. sidoides genotypes from the Active Germplasm Bank of the Federal University of Sergipe, and the influence of plant age on the content and chemical composition of its essential oil. Ten genotypes were analyzed in the years 2006 and 2012. The major compound of the genotypes was thymol, except for genotype LSID104, which present carvacrol as major compound. Age influenced the contents of essential oils in L. sidoides genotypes, and higher values were observed in two-year-old plants. Variations were observed in the proportions of the chemical constituents of the essential oils of the genotypes because of the aging process. There was low genetic control for the essential oil content; however, the chemical polymorphism in relation to the compounds thymol and carvacrol was caused by genotypes. Two clusters were detected by multivariate analysis for both ages. Cluster I was represented by the genotype LSID104, whereas cluster II was represented by genotypes LSID002, LSID003, LSID004, LSID005, LSID006, LSID102, LSID103, LSID105 and LSID301.