Anti-mycobacterial activity of tamoxifen against drug-resistant and intra-macrophage Mycobacterium tuberculosis

Abstract

Recently, it has become a struggle to treat tuberculosis with the current commercial antituberculosis drugs because of the increasing emergence of multidrug-resistant (MDR) tuberculosis and extensively drug-resistant (XDR) tuberculosis. We evaluated here the antimycobacterial activity of tamoxifen, known as a synthetic anti-estrogen, against eight drugsensitive or resistant strains of Mycobacterium tuberculosis (TB), and the active intracellular killing of tamoxifen on TB in macrophages. The results showed that tamoxifen had antituberculosis activity against drug-sensitive strains (MIC, 3.125-6.25 μg/ml) as well as drugresistant strains (MIC, 6.25 to 12.5 μg/ml). In addition, tamoxifen profoundly decreased the number of intracellular TB in macrophages in a dose-dependent manner.