Chemical variability of essential oils of Lippia alba (Miller) N. E. Brown growing in Costa Rica and Argentina.

Lippia alba (Verbenaceae) is a shrub whose essential oil has important biological, pharmacological, and aromatizing properties. The species has a natural range from Central America to Argentina, being cultivated for its commercial value in Brazil, Argentina and Guatemala, and has been introduced into India and Spain. To reach the economic potential of the plant, the present study was aimed at evaluating L. alba for different chemotypes. The composition of the essential oil from two native populations of L. alba, collected from Argentina and two accessions from Costa Rica, were screened by GC and GC-MS. The results obtained led us to adopt the concept of a biodistribution map, as was proposed previously for the species, representing an approach to the natural biological distribution of the species in America based on the chemotypes described and their geographical distribution. Moreover, the biodiversity reported for the species (seven of eight chemotypes described for L. alba are present in Argentina) suggests the southern region of South America as the centre of distribution for L. alba.