ABSTRACT
The genus Lippia Houst. consists of approximately 200 species of which 46 have been chemically examined. Because most of the species are aromatic, the studies on the chemistry of this genus are mostly related with the composition of the essential oils and only a very few ones devoted to the non-volatile constituents. An outstanding feature of Lippia is the difference observed in the essential oil composition reported for the same species from different geographic origins. The mono-and sesquiterpenoids found in the essential oils for all but two of the Lippia species investigated so far are quite common and widespread in the plant kingdom, the exceptions being L. integrifolia (Gris.) Hieron. which produces ketones based on the unique sesquiterpene skeletons named lippifoliane and integrifoliane and L. dulcis Trev. which contains ()-hernandulcin, a sesquiterpenoid 1500 times sweeter than sucrose. Iridoids glucosides, phenylpropanoids, naphthoquinoids and flavonoids are the four types of significant nonvolatile secondary metabolites reported in Lippia.
