IQG-607 abrogates the synthesis of mycolic acids and displays intracellular activity against Mycobacterium tuberculosis in infected macrophages

In this work, the antitubercular activity of a pentacyano(isoniazid)ferrate(II) compound (IQG-607) was investigated using a macrophage model of Mycobacterium tuberculosis infection. Importantly, treatment of M.-tuberculosis-infected macrophages with IQG-607 significantly diminished the number of CFU compared with the untreated control group. The antitubercular activity of IQG-607 was similar to that observed for the positive control drugs isoniazid and rifampicin. Nevertheless, higher concentrations of IQG-607 produced a significantly greater reduction in bacterial load compared with the same concentrations of isoniazid. Analysis of the mechanism of action of IQG-607 revealed that the biosynthesis of mycolic acids was blocked. The promising activity of IQG-607 in infected macrophages and the experimental determination of its mechanism of action may help in further studies aimed at the development of a new antimycobacterial agent.