Use of Resazurin for Studying the Intracellular Activity of Low Molecular Weight Anti-Tuberculosis Compounds

The use of the redox indicator resazurin for estimating the intracellular activity of the original derivative of pyrano[3,2-b]indolone Pyr056 with anti-tuberculosis activity in vitro was proposed in the work. The estimation of the number of M. tuberculosis in the cultures of infected macrophage cell line RAW264.7 treated with Pyr056 by counting CFU and by measuring the fluorescence intensity of reduced resazurin demonstrated a high degree of positive correlation (r = 0.982). On the one hand, this result opens up the prospect of further study of the anti-tuberculosis activity of Pyr056, including in vivo experiments; on the other hand, the possibility of using resazurin for rapid and accurate estimation of the efficiency of experimental compounds against various intracellular pathogens, including M. tuberculosis, especially in the case of limited time and resources.