Open AccessAntibacterial activity of lichen secondary metabolite usnic acid is primarily caused by inhibition of RNA and DNA synthesis
Author(s) -
MaciągDorszyńska Monika,
Węgrzyn Grzegorz,
GuzowKrzemińska Beata
Publication year - 2014
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/1574-6968.12409
Subject(s) - usnic acid , bacillus subtilis , biology , escherichia coli , dna , rna , dna synthesis , bacteria , microbiology and biotechnology , staphylococcus aureus , mechanism of action , biochemistry , transcription (linguistics) , protein biosynthesis , antibacterial activity , dna replication , gene , lichen , in vitro , genetics , linguistics , botany , philosophy
Usnic acid, a compound produced by various lichen species, has been demonstrated previously to inhibit growth of different bacteria and fungi; however, mechanism of its antimicrobial activity remained unknown. In this report, we demonstrate that usnic acid causes rapid and strong inhibition of RNA and DNA synthesis in Gram‐positive bacteria, represented by Bacillus subtilis and Staphylococcus aureus , while it does not inhibit production of macromolecules ( DNA , RNA , and proteins) in Escherichia coli , which is resistant to even high doses of this compound. However, we also observed slight inhibition of RNA synthesis in a Gram‐negative bacterium, Vibrio harveyi . Inhibition of protein synthesis in B. subtilis and S. aureus was delayed, which suggest indirect action (possibly through impairment of transcription) of usnic acid on translation. Interestingly, DNA synthesis was halted rapidly in B. subtilis and S. aureus , suggesting interference of usnic acid with elongation of DNA replication. We propose that inhibition of RNA synthesis may be a general mechanism of antibacterial action of usnic acid, with additional direct mechanisms, such as impairment of DNA replication in B. subtilis and S. aureus .