Behavioral effects of essential oils from Lippia alba (Mill.) N.E.!Brown chemotypes

This work presents behavioral effects of three chemotypes of essential oils (EO) from Lippin alba (Mill.) N.E. Brown (Verbenaceae) on elevated plus maze, open field and rota rod tests and also on rectal temperature in mice. The results showed that all three EO increased significantly not only the number and percentage of entries, but also the time and percentage of time of permanence in the open arms. Greater effects were presented by EO II (50 mg/kg, i. p.) as related to controls for all parameters studied. In the open field test, while EO I(200 mg/kg, i. p.) decreased only the number of rearing as compared to controls, EO II and III (100 and 200 mg/kg, i. p., respectively) decreased both the number of rearing and grooming as compared to controls. None of them altered the number of crossings. In the rota rod test, only EO II (200 mg/kg, i. p.) decreased the time of permanence on the bar related to controls. All three EO decreased the rectal temperature at the doses of 100 and 200 mg/kg, i.p. EO I contains citral, beta-myrcene and limonene as the main constituents, while citral and limonene are present in EO II, and carvone and limonene in EO III. Citral and beta-myrcene seem to be the main active components of EO I and II, However, carvone and limonene are also active and probably responsible for the effects observed with EO III. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.