Quinolone-isoniazid hybrids: synthesis and preliminary <i>in vitro</i> cytotoxicity and anti-tuberculosis evaluation.
Beteck RM, Seldon R, Jordaan A, Warner DF, Hoppe HC, Laming D, Legoabe LJ, Khanye SD.
Herein, we propose novel quinolones incorporating an INH moiety as potential drug templates against TB. The quinolone-based compounds bearing an INH moiety attached <i>via</i> a hydrazide-hydrazone bond were synthesised and evaluated against <i>Mycobacterium tuberculosis</i> H37Rv (MTB). The compounds were also evaluated for cytotoxicity against HeLa cell lines. These compounds showed significant activity (MIC<sub>90</sub>) against MTB in the range of 0.2-8 μM without any cytotoxic effects. Compounds <b>10</b> (MIC<sub>90</sub>; 0.9 μM), <b>11</b> (MIC<sub>90</sub>; 0.2 μM), <b>12</b> (MIC<sub>90</sub>; 0.8 μM) and compound <b>15</b> (MIC<sub>90</sub>; 0.8 μM), the most active compounds in this series, demonstrate activities on par with INH and superior to those reported for the fluoroquinolones. The SAR analysis suggests that the nature of substituents at positions -1 and -3 of the quinolone nucleus influences anti-MTB activity. Aqueous solubility evaluation and <i>in vitro</i> metabolic stability of compound <b>12</b> highlights favourable drug-like properties for this compound class.