Structure-activity relationship of natural and synthetic coumarin derivatives against <i>Mycobacterium tuberculosis</i>

Aim: Eight coumarin derivatives ( 1a-h ) obtained from natural (-)-mammea A/BB ( 1 ) and 13 synthetic coumarins ( 2-14 ) had their cytotoxicity and biological activity evaluated against Mycobacterium tuberculosis H 37 Rv reference strain and multidrug-resistant clinical isolates. Materials & methods: Anti- M. tuberculosis activity was evaluated by resazurin microtiter assay plate, and the cytotoxicity of natural and synthetic products using J774A.1 macrophages by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. Results: Compounds 1g , 5 , 6 , 12 and 14 were more active against M. tuberculosis H 37 Rv and multidrug-resistant clinical isolates with MIC values ranging from 15.6 to 62.5 μg/ml. Conclusion: These results demonstrate that the coumarin derivatives were active against multidrug-resistant clinical isolates, becoming potential candidates to be used in the treatment of resistant tuberculosis.