Synthesis of novel (-)-Camphene-based thiosemicarbazones and evaluation of anti-<i>Mycobacterium tuberculosis</i> activity

<p>In this work the aim of study was the synthesis and evaluation of <i>in vitro</i> anti-<i>Mycobacterium tuberculosis</i> activity as well as the cytotoxicity in VERO cells of a series of 17 novel thiosemicarbazones derived from the natural monoterpene (-)-camphene by REMA and MTT methods. Overall, the majority of tested compounds exhibited considerable inhibitory effects on the growth of <i>M. tuberculosis</i> H₃₇Rv, especially the derivatives <b>3</b>, <b>4a–c</b>, <b>4f</b>, <b>4i</b>, <b>4k</b>, <b>5</b> and <b>6a–b</b>. MIC values of 20 tested compounds ranged from 3.9 to > 250 μg/mL. It was found that when inserting new nitrogenous groups to the (-)-camphene increased the anti-<i>M. tuberculosis</i> activity of some compounds. The SI was calculated for all compounds that showed highly potent anti-<i>M. tuberculosis</i> activity and the best SI values were 21.36, 26.92 and 31.62 (<b>4b</b>, <b>6a</b> and <b>6b</b>), and may be considered potential candidates for future antituberculosis drugs.</p