5-Nitroisatin-derived thiosemicarbazones: potential antileishmanial agents

Abstract

A series of 29 previously reported N⁴-substituted 5-nitroisatin-3-thiosemicarbazones 2–30 has been screened for leishmanicidal potential. Compounds 2–4, 7, 8, 10–13, 15–19, 21, 23, 24, 26, 28 and 30 exhibited good to excellent antileishmanial activities with IC₅₀ values ranging from 0.44 ± 0.02 to 32.38 ± 0.66 µg/mL. Of these, 5, 7, 19 and 28 proved to be the most active antileishmanial agents, displaying activities with IC₅₀ values 1.78 ± 0.35, 0.44 ± 0.02, 1.91 ± 0.04 and 4.28 ± 0.75 µg/mL, respectively, which were even better than the standard drug, pentamidine (IC₅₀ = 5.09 ± 0.04 µg/mL). This study presents the first example of exhibition of leishmanicidal potential by isatin-thiosemicarbazones and as such furnishes a solid basis for further research on these compounds to develop more potent antileishmanial agents.

• Isatin-thiosemicarbazones
• leishmanicidal activity
• Leishmania major