Anti-trypanosomal activities and structural chemical properties of selected compound classes.

Potent compounds do not necessarily make the best drugs in the market. Consequently, with the aim to describe tools that may be fundamental for refining the screening of candidates for animal and preclinical studies and further development, molecules of different structural classes synthesized within the frame of a broad screening platform were evaluated for their trypanocidal activities, cytotoxicities against murine macrophages J774.1 and selectivity indices, as well as for their ligand efficiencies and structural chemical properties. To advance into their modes of action, we also describe the morphological and ultrastructural changes exerted by selected members of each compound class on the parasite Trypanosoma brucei. Our data suggest that the potential organelles targeted are either the flagellar pocket (compound 77, N-Arylpyridinium salt; 15, amino acid derivative with piperazine moieties), the endoplasmic reticulum membrane systems (37, bisquaternary bisnaphthalimide; 77, N-Arylpyridinium salt; 68, piperidine derivative), or mitochondria and kinetoplasts (88, N-Arylpyridinium salt; 68, piperidine derivative). Amino acid derivatives with fumaric acid and piperazine moieties (4, 15) weakly inhibiting cysteine proteases seem to preferentially target acidic compartments. Our results suggest that ligand efficiency indices may be helpful to learn about the relationship between potency and chemical characteristics of the compounds. Interestingly, the correlations found between the physico-chemical parameters of the selected compounds and those of commercial molecules that target specific organelles indicate that our rationale might be helpful to drive compound design toward high activities and acceptable pharmacokinetic properties for all compound families.

In search of novel agents for therapy of tropical diseases and human immunodeficiency virus.

Malaria, sleeping sickness, Chagas' disease, Aleppo boil, and AIDS are among the tropical diseases causing millions of infections and cases of deaths per year because only inefficient chemotherapy is available. Since the targeting of the enzymes of the polyamine pathway may provide novel therapy options, we aimed to inhibit the deoxyhypusine hydroxylase, which is an important step in the biosynthesis of the eukaryotic initiation factor 5A. In order to identify new lead compounds, piperidines were produced and biologically evaluated. The 3,5-diethyl piperidone-3,5-dicarboxylates 11 and 13 substituted with 4-nitrophenyl rings in the 2 and 6 positions were found to be active against Trypanosoma brucei brucei and Plasmodium falciparum combined with low cytotoxicity against macrophages. The corresponding monocarboxylates are only highly active against the T. brucei brucei. The piperidine oximether 53 demonstrated the highest plasmodicidal activity. Moreover, compounds 11 and 53 were also able to inhibit replication of HIV-1.