Azole-based non-peptidomimetic plasmepsin inhibitors.

The spread of drug-resistant malaria parasites urges the search for new antimalarial drugs. Malarial aspartic proteases - plasmepsins (Plms) - are differentially expressed in multiple stages of the Plasmodium parasite's lifecycle and are considered as attractive drug targets. We report the development of novel azole-based non-peptidomimetic plasmepsin inhibitors that have been designed by bioisosteric substitution of the amide moiety in the Actelion amino-piperazine inhibitors. The best triazole-based inhibitors show submicromolar potency toward Plm II, which is comparable to that of the parent Actelion compounds. The new inhibitors can be used as a starting point for the development of a resistance-free antimalarial drug targeting the non-digestive Plm IX or X, which are essential for the malaria parasite life cycle.