Abstract

In Chile there is a diverse and abundant lichenic mycobiota in terms of biomass. Within this diversity, Pseudocyphellaria Vainio (Lobariaceae, lichenized Ascomycota) is one of the lichen genera with the highest number of species (fifty-four) in the country and is distributed from north to south from Cerro Moreno (23°27ʹ52ʺ S). to Cabo de Hornos (55°58ʹ48ʺ S). 72% of the species in this genus are endemic to southern South America. A widely distributed species in Chile is Pseudocyphellaria berberina (G. Forst.) D.J. Galloway and P. James, it is present from Isla Mocha to Tierra del Fuego and is also found in the Archipelago de Juan Fernández. In this work, the identification and characterization of the major metabolites present in Pseudocyphellaria berberina was carried out and their antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa was evaluated. The major metabolites were spectroscopically characterized and identified as pseudocyphellarine A, 22-hydroxystictan-3-one, and physiosporin. Compounds derived from shikimic acid, such as calicin and pulvinic dilactone, were also isolated. The antimicrobial evaluation was carried out by the broth microdilution method. Physiosporin showed an inhibitory (MIC= 246 μg/mL) and bactericidal (CMB= 492 μg/mL) effect on S. aureus. 22-hydroxystictan-3-one on the other hand prevented the adhesion of S. aureus at sub-inhibitory concentrations. The antimicrobial activity of these compounds has not been previously reported; therefore, they are promising candidates to advance in the evaluation of their bioactivity.