Resumo

Introduction: Ilex paraguariensis A. St-Hil. (Aquifoliaceae) is a native plant species from South America that is mainly found in Brazil, Paraguay, Uruguay and Argentina. It is popularly known as yerba mate and the infusion of its leaves and twigs, named ‘chimarrão’, ‘tererê’ or mate, is used for preparing food and stimulating drinks. Its phytochemical profile shows the presence of polyphenols (chlorogenic acid) and xanthines (caffeine, theophylline and theobromine) as main constituents, followed by saponins and flavonoids. However, few studies portray the neuropharmacological profile of this plant. Thus, the aim of the present study was to evaluate the putative effects on animal tests of anxiety after acute and subacute administration of aqueous and ethanolic extracts of Ilex paraguariensis. Methods: Swiss male mice (3-4 month) were intragastrically pretreated with the aqueous and ethanolic extract (60 - 600mg/kg) or vehicle (saline). Animals were evaluated in the elevated plus maze (EPM) and in the black and white box (BWB), 1h after acute or subacute administration (three doses in 24h). The following parameters were evaluated: time and entries in open arms, total of entries, enclosed arm entries, stretch attend postures, head-dipping, rearing, grooming (EPM); and latency to enter into the dark compartment and time spent on the light side, besides the number of transitions between compartments (BWB). Subsequently, the open field test was performed to check the locomotor activity of animals. All protocols were approved by local Ethics Committee (23080.013794/2009-71/CEUA/UFSC). Data were analyzed by one way ANOVA followed by Dunnett's test. Results: There was a significant increase in the number of enclosed arm entries (control: 12.8 ± 5.6; 300mg/kg: 25.1 ± 13.6) and total of entries (control: 16.2 ± 7.4 ; 300mg/kg: 28.3 ± 15.1) in the EPM test, parameters related to locomotor activity, after the subacute treatment with the ethanolic extract. However, no other parameters were significantly altered after the acute or subacute treatment with both extracts in the range of doses here tested. In the open field test, animals subacutely treated with 600mg/kg of ethanolic extract showed an increase in locomotor activity too (control: 104,9±40,2; 600mg/kg: 152,0±25,9). Discussion: Our results showed that the aqueous and ethanolic extracts obtained from leaves of Ilex paraguariensis did not promote any significant changes in the behavioral parameters related to anxiety. However, the increase in the entries into the enclosed arms can be attributed to the stimulating action of the extract, as confirmed in the open-field, probably resulting from the presence of methylxanthines in this extract. Financial support: CNPq