Tuberculosis (TB -
Mycobacterium tuberculosis
) is an ancient infectious disease that has appeared once again
as a serious worldwide health problem and now comprises the second leading cause of death resulting from a single
infection. The prevalence of multidrug resistance (MDR) TB is increasing and therapeutic options for treatment are
not always accessible; in fact, some patients do not respond to the available drugs. Therefore, there is an urgent
need to develop novel anti-TB agents. The aim of the present study was to screen extracts of
Aristolochia taliscana
,
a plant used in traditional Mexican medicine to treat cough and snake bites, for antimycobacterial activity. The
hexanic extract of
A. taliscana was tested by microdilution alamar blue assay against
Mycobacterium
strains and
bioguided fractionation led to the isolation of the neolignans licarin A, licarin B and eupomatenoid-7, all of which
had antimycobacterial activity. Licarin A was the most active compound, with minimum inhibitory concentrations
of 3.12-12.5 μg/mL against the following
M. tuberculosis strains: H37Rv, four mono-resistant H37Rv variants and 12
clinical MDR isolates, as well as against five non-tuberculous mycobacteria (NTM) strains. In conclusion, licarin A
represents a potentially active anti-TB agent to treat MDR
M. tuberculosis and NTM strains.