A novel class of compounds may now combat Kala-azar or leishmaniasis . Known as aryloxy cyclohexane-based mono and bis imidazoles, the compounds stifle the growth of Leishmania donovani , the parasite that causes Kala-azar1.

The researchers successfully tested the efficacy of the compounds in lab as well as animal models. The compounds could be a new drug candidate against Kala-azar. To the problem of drug resistance, the researchers synthesized the new compounds and studied their effects in cell culture and animals against leishmania parasites.

All the compounds showed response against both forms of the parasite — promastigote and amastigote (promastigotes enter the human body through sand-fly bites and morph into amastigotes). Compounds having anti-amastigote activity were picked up for animal studies since amastigotes are responsible for the disease.

Thirteen compounds showed very promising results in cell culture. Of them, one compound known as bis methylimidazole with 2-fluoro, 4-nitro aryloxy group significantly inhibited the growth of parasites in animals.

These compounds are better than the existing drugs like sodium stibogluconate and pentamidine and provide new lead for anti-leishmanial agents, the researchers say.