Abstract
The antibiotic activity of lichenic compounds atranorin, physodic, and stictic acid isolated from Menegazzia terebrata were analyzed. The antibiotic bioactivity was assessed against eight bacterial inoculums i.e., 3 g positive and 5 g negative by analyzing the minimal inhibitory
concentrations (MICs) using the broth tube dilution method. All lichenic compounds showed antibiotic activities. The maximum bacterial growth inhibition activity was observed by atranorin (MIC, 0.030-0.5 mg/mL) and the minimum in physodic acid (MIC, 1 mg/mL). Stictic acid (MIC, 0.25-0.5
mg/mL) exhibited moderate antibiotic activity. Among the tested bacterial inoculums, all lichenic compounds reported antibacterial activity against a streptomycin-resistant strain of Pseudomonas aeruginosa. As a result, the study referred to the antibiotic potential of lichenic compounds,
which could be developed further for pharmaceutical purposes.