Isolamento do principal constituinte ativo do óleo essencial de Lippia alba (Mill.) N. E. Brown com potencial anestésico geral e estudo do mecanismo de ação

Abstract

Lippia alba (Mill.) N. E. Brown is an aromatic herb commonly used as sedative and for the treatment of gastrointestinal disturbs. Many literature data confirm the sedative property of the essential oil (EO) of this species; however, just recently its anesthetic activity was confirmed. The present study reports the isolation of two major chemical constituents of the EO of L. alba, linalool and eucalyptol, and also the evaluation of their anesthetic activity in juveniles of silver catfish (Rhamdia quelen). Additionally, linalool was defined as the major active compound of the EO with anesthetic property, and eucalyptol did not presented activity in the tested concentration. The involvement of GABAergic system on the mechanism of action of the EO and its major constituent was also studied. The results showed that the EO contains one or more compounds which act in synergism with linalool and also by different mechanism. Benzodiazepine like effect was detected for the EO of L. alba, but not for linalool. In addition, this work brings a case report of contact dermatitis caused by the leaves of L. alba chemotype linalool. Finally, to establish a good quality of the plant material, after yield and chemical composition analyses of the EO, 1,0 x 0,8 m was defined as the better spacing for cultivation of L. alba. The results are presented in three manuscripts.