Discovery of quinolone derivatives as antimycobacterial agents?

RSC Advances Pub Date: 2021-07-08 DOI: 10.1039/D0RA09250A

Abstract

Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis (M. tuberculosis), is an important public health issue. Current first-line drugs administered to TB patients have been in use for over 40 years, whereas second-line drugs display strong side effects and poor compliance. Additionally, designing effective regimens to treat patients infected with multi- and extremely-drug-resistant (MDR and XDR) strains of TB is challenging. In this report, we screened our compound library and identified compound 1 with antituberculosis activity and a minimal inhibitory concentration (MIC) against M. tuberculosis of 20 μg mL?1. Structure optimization and the structure–activity relationship of 1 as the lead compound enabled the design and synthesis of a series of quinolone derivatives, 6a1–6a2, 6b1–6b36, 6c1, 6d1–6d14, 7a1–7a2, 7b1–7b2, 7c1, 8a1–8a5, 9a1–9a4 and 10a1–10a6. These compounds were evaluated in vitro for anti-tubercular activity against the M. tuberculosis H37Rv strain. Among them, compounds 6b6, 6b12 and 6b21 exhibited MIC values in the range of 1.2–3 μg mL?1 and showed excellent activity against the tested MDR-TB strain (MIC: 3, 2.9 and 0.9 μg mL?1, respectively). All three compounds were non-toxic toward A549 and Vero cells (>100 and >50 μg mL?1, respectively). In addition, an antibacterial spectrum test carried out using compound 6b21 showed that this compound specifically inhibits M. tuberculosis. These can serve as a new starting point for the development of anti-TB agents with therapeutic potential.

Graphical abstract: Discovery of quinolone derivatives as antimycobacterial agents
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