INTRODUÇÃOLippia alba ocorre nas américas Central e do Sul, habitando praticamente todas as regiões do Brasil, onde é muito empregada como medicinal, pelas suas propriedades sedativa, carminativa, analgésica, espasmolítica e emenagoga (Zétola et al., 2002;Vale et al., 1999;Matos et al., 1996) Unitermos: Lippia alba, Verbenaceae, óleo essencial, citral, carvona, linalol.ABSTRACT: "Analysis of the essential oil from leaves of three Lippia alba (Mill.) N. E. Br. (Verbenaceae) chemotypes cultivated on the same conditions". The composition of Lippia alba essential oil varies in a manner that different chemotypes are recognized. This work deals with the analysis of the essential oil from three chemotypes of L. alba from different regions of Brazil, cultivated in similar conditions, to verify if the differences in their chemical composition can be due to environmental conditions or may be due to infra-specifi c genetic variation. The infl uence of fl owering was investigated regarding essential oil yield and composition. The chemotypes producing citral, carvone and linalol were denominated chemotypes 1, 2 and 3, respectively. The essential oils were obtained by hydrodistillation of the leaves, at fl owering and vegetative growth stages. Essential oils were analyzed by GC and GC/MS. A better yield was obtained from plants at vegetative stage. The composition of the essential oils remained unchanged after cultivation in the same conditions, and did not vary qualitatively during fl owering and vegetative periods. Relative percentages of the major compounds changed during fl owering period. Data obtained allow us to reinforce the idea that differences in the essential oil composition of the three chemotypes are due to genotypic variations and that the essential oil extraction during the vegetative period enables a better yield and higher percentages of the major compounds.

.J.A. As ervas cidreiras do Nordeste do Brasil. Estudo de três quimiotipos de Lippia alba (Mill.) N. E. Brown (Verbenaceae) Parte II -Farmacoquímica. Rev. Bras. Farm., v. 77, n. 4, p. 137-141, 1996. 11 Ellis, M.D. ; Baxendale, F. P. Toxity of seven monoterpenoids to tracheal mites (Acari: Tarsonemidae) and their honey bee (Hymenoptera : Apidae) hosts when applied as fumigants.

Tuberculosis (TB), caused by Mycobacterium tuberculosis, is the world's number one killer among infectious diseases. The search for new natural products that can act as drugs against TB has received increased attention during the last years. In this work we describe the isolation and identification of the active antimycobacterial principles of the dichloromethane extract from Lippia lacunosa Mart. & Schauer, Verbenaceae. Compounds were evaluated for their in vitro activity against Mycobacterium tuberculosis (susceptible and rifampicin resistant strain) using a redox bioassay. From the dichloromethane extract of L. lacunosa leaves, seven methoxy-flavones named cirsimaritin (1), eupatilin (2), eupatorin (3), salvigenin (4), 3′-O-methyl-eupatorin (5), 3′,7-dimethoxy-5,6,4′-trihydroxyflavone (6), and 7′-O-methylapigenin (7), and one triterpene, named oleanolic acid (8), were isolated. All compounds were found to display antimycobacterial activity against susceptible strain, with MIC ranging from 25 to 200 µg/mL. None of them was active against rifampicin resistant strain. This is the first report in the antimycobacterial activity of 6-substituted flavones, as well as the first report of the occurrence of these substances in L. lacunosa.