Seasonal variations during two years in the essential oil of Lippia dulcis Trevir., an exotic aromatic of the Amazon

Lippia dulcis Trevir. (Verbenaceae) is an aromatic plant occurring in the Amazon that has leaves and flowers with a sweet taste. The objective of this study was to evaluate the influence of seasonal variation during two consecutive years on the content and chemical composition of the essential oil (EO) of L. dulcis leaves. The EO content and chemical composition were influenced by precipitation, temperature, and plant age. The EO content ranged from .1 to .5%. The chemical profile of the EO did not vary significantly among seasons. The main constituents identified were the oxygenated bisabolane-type sesquiterpenes epi-α-bisabolol and hernandulcin. The highest concentration of hernandulcin was observed in the dry period, characterized by mild temperatures and the juvenile stage of plant growth. The highest concentrations of epi-α-bisabolol were observed in the hottest and wettest season of each year.