Atividade antibacteriana, antifúngica e moduladora da atividade antimicrobiana de frações obtidas de Lygodium venustum SW (Antibacterial, antifungal and antimicrobial modulatory activities of fractions from Lygodium venustum SW)

The traditional use of plants in popular medicine has also indicated the way in the search for pharmacological agents. The need for new drugs is evidenced by the strong resistance of microorganisms. The fern Lygodium venustum had its antimicrobial potential measured, in this work, by the broth microdilution method. Its ability to modulate the action of antibiotics was also tested. Its hexane, dichloromethane and methanol fractions obtained from the ethanolic extract of fresh leaves were assayed. The Minimum Inhibitory Concentration was evaluated from the standard strains of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Candida albicans, Candida tropicalis and Candida krusei. To check the modulating activity of antibiotics were used multi-resistant strains of P. aeruginosa, E. coli and S. aureus and the same yeast strains used in CIM. The drugs used in modulating were antifungal and aminoglycosides. All results showed MIC ≥1024μg/mL activity. The fractions neither enhanced the action of antifungal agents against strains of Candida, nor the aminoglycosides against P. aeruginosa. However, interesting results potentiating the action of these were obtained against the E. coli and S. aureus. Such results suggest that secondary metabolites which are in this plant may be used to create new drugs in combination with aminoglycosides. This was the first report of activity-modifying action of antibiotics for fractions obtained from a fern family Lygodiaceae.