CNS activities of liquid and spray-dried extracts from Lippia alba—Verbenaceae (Brazilian false melissa)

Abstract

The CNS activity of Lippia alba liquid and spray-dried extracts, containing the non-volatile fraction from the leaves, was investigated. L. alba liquid extracts were prepared by percolation with EtOH 40, 60 or 80%. The liquid extracts, named ES 40%, ES 60% and ES 80%, were concentrated, the ethanol eliminated and then tested in Swiss mice to evaluate its sedative and anticonvulsant effects. The animals received the extracts, orally, in doses corresponding to 200 mg of dry residue by kilogram of body weight. All mice were evaluated in the barbiturate-induced sleep test. Similarly, other groups of mice were submitted to convulsions induced by pentylenetetrazol (PTZ). The concentrated extract obtained from ES 80% showed the most significant sedative and myorelaxant effects as well as the highest total flavonoid content (66 mg/100 g, expressed in apigenin). Two spray-dried powders, SDP 1 and SDP 2, were prepared from ES 80% using as excipients, respectively, colloidal silicon dioxide (CSD) and CSD associated to β-cyclodextrin. Only SDP 1 showed sedative profile similar to that presented by ES 80. In conclusion, we demonstrated that the non-volatile fraction of L. alba, extracted in ethanol 80% (v/v), presents sedative and myorelaxant effects and that, among the tested extracts, this presents the highest flavonoid content. We demonstrated also the technological feasibility of spray-dried extracts and the influence of the excipient on its sedative properties.