IN-VITRO ACTIVITIES OF THE LICHEN SECONDARY METABOLITES VULPINIC ACID, (-USNIC ACID, AND (-)-USNIC ACID AGAINST AEROBIC AND ANAEROBIC MICROORGANISMS())

Secondary metabolites of different species of lichen were tested for t heir activities against a variety of microbial species. While gram-neg ative rods and fungi were not inhibited by these compounds, Staphyloco ccus aureus, Enterococcus faecalis, Enterococcus faecium, and some ana erobic species (Bacteroides and Clostridium species) were susceptible at the concentrations tested. Vulpinic acid generally was less active than usnic acid, regardless of its stereochemistry. The susceptibility to usnic acid was not impaired in clinical isolates of S. aureus resi stant to methicillin and/or mupirocin.