Characterization of the activity of (+)-usnic acid and its new derivatives against M. tuberculosis and selected non-tuberculous mycobacterium strains

Due to the rising incidence of tuberculosis (TB) worldwide and the emergence of multidrug resistant (MDR) strains, the development of new antituberculous drugs to reduce the duration of the treatment and fight MDR-TB is urgently needed. Usnic acid is reported to have antimycobacterial properties in vitro on susceptible and resistant strains, but because of its rapid metabolism and toxicity prevents further exploitation. The aim of this study is to characterize the activity of usnic acid and its derivatives, against M. tuberculosis susceptible, resistant and MDR strains and selected non-tuberculous mycobacterium strains.