p‑Alkoxy-Substituted Anisomycins with Potent Anti-Trypanosomiasis Activity and Expanded Modes of Action

Neglected tropical diseases caused by trypanosomatid parasites present a major public healthcare issue, partly due to emerging resistance. Attachment of ω-alkynyl chains characteristic of the lipid tails of antiparasitic peptides to the p-position of anisomycin gave ethers exhibiting potent activity, rivalling that of the parent ribosomal inhibitor, especially against resistant Leishmania strains. Single-particle cryoelectron microscopy analysis revealed that O-propargyl anisomycin binds to the highly conserved peptidyl transferase center of the ribosome similar to the parent inhibitor. Thermal proteomic profiling and gene ontology analysis demonstrated that O-propargyl anisomycin exhibited a broader mode of action, including activity against glycosome-associated proteins. Alkynyl substituents improved antiparasitic activity against resistant strains, likely by enlarging the mode of action, offering a novel path toward therapy against trypanosomatid infections.