Antimicrobial activity of fumarprotocetraric acid, lecanoric acid, protocetraric acid and stictic acid isolated from different species of lichen

The antimicrobial activity of fumarprotocetraric acid, lecanoric acid, protocetraric acid and stictic acid isolated from the lichens Cladonia furcata (Huds.) Schrad., Ochrolechia androgyna (Hoffm.) Arn., Parmelia caperata (L.) Ach. and Parmelia conspresa (Ach.) Ach. was studied for the following microorganisms: Bacillus mycoides, Bacillus subtilis, Staphylococcus aureus, Enterobacter cloaceae, Escherichia coli, Klebsiella pneumoniae, Aspergillus flavus (ATCC 9170), Aspergillus fumigatus, Botrytis cinerea, Candida albicans, Fusarium oxysporum, Mucor mucedo (ATCC 52568), Paecilomyces variotii (ATCC 22319), Penicillium purpurescens, Penicillium verrucosum, Trichoderma harsianum. Aspergillus flavus, Mucor mucedo and Paecilomyces variotii are ATCC type, and the other microorganisms are clinical isolates. The antimicrobal activity was estimated by determining the minimum inhibitory concentration (MIC) by the Broth tube Dilution method. The tested lichen components ihibited growth of all the tested microrganisms. The bacteria showed a bigger sensitivity relative to fungi. The lowest MIC value (0.031mg/mL) was measured for the fumarprotocetraric acid related to the Klebsiella pneumoniae species. The weakest antimicrobial activity was found in stictic acid, which inhibited most of the tested microorganisms in significantly higher concentrations. Generally, all the components had relatively strong antimicrobial activity against the tested microorganisms.