Antimycobacterial neolignans isolated from Aristolochia taliscana

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 ìg/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.

Analysis of the Cell Lysate Proteome of a Korean Mycobacterium tuberculosis Isolate K01 with H37Rv and H37Ra Strains

Despite recent economic prosperity, Korea still has high prevalence of tuberculosis. Molecular biologic characterization of Korean Mycobacterium tuberculosis strains might provide a deeper understanding of the forces contributing to the spread of tuberculosis in Korea. Therefore, we analyzed the cell lysate proteome of a representative Korean Mycobacterium tuberculosis isolate (K01) in comparison with laboratory reference strains H37Rv and H37Ra. Seven spots were strongly expressed only in K01 strain compared with M. tuberculosis H37Rv and H37Ra. Through continuous MALDI-MS analysis, these spots were identified as hypothetical protein Rv3849, secreted immunogenic protein Mpt64, Acetyl/propionyl-CoA Carbpxylase (AccD1), alkyl hydroperoxide reductase C (AhpC), N-acetylmuramyl-L-alanine amidase, a putative UDP glucose epimerase, and a transposase. A deeper study of these proteins may provide a clue in the development of effective new anti-tuberculosis vaccines against Korean M. tuberculosis isolates.