Resumo

Natural products provide major sources of innovative bioactive compounds. Traditional usage is an important strategy to achieve new substances systematically. Brazilian indigenous Mbyá-Guarani communities have a rich heritage about medicinal plants uses. For infectious disease treatment, specifically, cough with abundant secretion, a specific plant is employed. Regarding infectious diseases on the hospital perspective, nosocomial infections are well known to be one of the most challenging problems when the microbial are organized in biofilms, a complex way of life notably more resistant to antibiotics and the host immune system. The aim of this work was to investigate antibiotic and antibiofilm activities of this plant supported by Mbyá-Guarani traditional usage against the pathogens Pseudomonas aeruginosa and Staphylococcus epidermidis. Aqueous, hydroalcoholic, acetonitrile and ethyl acetate extracts from plant barks had antibiofilm and antibiotic activities assayed against P. aeruginosa and S. epidermidis. The in vitro activity was corroborated by kinetic growth curve and scanning electron microscopy (SEM). Also, hemolytic activity against human erythrocytes of active extracts were performed. Aqueous, hydroalcoholic and acetonitrile extracts strongly inhibited the biofilm formation for both pathogens; in contrast, ethyl acetate extract showed effect only upon S. epidermidis biofilm formation. The hydroalcoholic extract acted inhibiting the bacterial adhesion without antibiotic activity to S. epidermidis. Otherwise, for P. aeruginosa, the extract inhibited the biofilm formation as a consequence of a bactericidal effect. This fact was evidenced by SEM images that demonstrated distinct profiles of bacterial adhesion, matrix production, and bacterial morphology. In addition, hydroalcoholic extract did not promote a significant hemolytic activity against human erythrocytes. Furthermore, our study confirms the ethnopharmacological usage of plants by Indians Mbyá-Guarani for cough with secretion, emphasizing the importance of indigenous knowledge in the search for new bioactive agents.