Evaluation and discovery of novel benzothiazole derivatives as promising hits against Leishmania infantum.

An early exploration of the benzothiazole class against two kinetoplastid parasites, Leishmania infantum and Trypanosoma cruzi, has been performed after the identification of a benzothiazole derivative as a suitable antileishmanial initial hit. The first series of derivatives focused on the acyl fragment of its class, evaluating diverse linear and cyclic, alkyl and aromatic substituents, and identified two other potent compounds, the phenyl and cyclohexyl derivatives. Subsequently, new compounds were designed to assess the impact of the presence of diverse substituents on the benzothiazole ring or the replacement of the endocyclic sulfur by other heteroatoms. All compounds showed relatively low cytotoxicity, resulting in decent selectivity indexes for the most active compounds. Ultimately, the in vitro ADME properties of these compounds were assessed, revealing a satisfying water solubility, gastrointestinal permeability, despite their low metabolic stability and high lipophilicity. Consequently, compounds 5 and 6 were identified as promising hits for further hit-to-lead exploration within this benzothiazole class against L. infantum, thus providing promising starting points for the development of antileishmanial candidates.

The use of Sulfonamide Derivatives in the Treatment of Trypanosomatid Parasites including Trypanosoma cruzi, Trypanosoma brucei, and Leishmania ssp.

More than 10 million people around the world are afflicted by Neglected Tropical Diseases, such as Chagas Disease, Human African Trypanosomiasis, and Leishmania. These diseases mostly occur in undeveloped countries that suffer from a lack of economic incentive, research, and policy for new compound development. Sulfonamide moieties are effective scaffolds present in several compounds that are determinants to treat various diseases, principally neglected tropical diseases. This review article examines the contribution of these scaffolds in medicinal chemistry in the last five years, focusing on three trypanosomatid parasites: Trypanosoma cruzi, Trypanosoma brucei, and Leishmania ssp. We also present perspectives for their use in drug designs in an effort to contribute to new drug development. In addition, we consider the physicochemical parameters, whose molecules all presented according to Lipinski's rule. The correlation between the selective index and LogP was evaluated, showing that sulfonamide derivatives can act differently against each trypanosomatid parasite. Moreover, the approaches of novel drugs and technologies are very important for the eventual drug discovery against trypanosomatid diseases.

Hit-to-lead optimization of a benzene sulfonamide series for potential antileishmanial agents.

A series of benzene sulphonamides with good potency and selectivity against Leishmania spp. intracellular amastigotes was identified by high-throughput screening. Approximately 200 compounds were synthesized as part of a hit-to-lead optimization program. The potency of the series appears to be strongly dependent on lipophilicity, making the identification of suitable orally available candidates challenging due to poor pharmacokinetics. Despite not identifying a clinical candidate, a likely solvent exposed area was found, best exemplified in compound 29. Ongoing detailed mode-of-action studies may provide an opportunity to use target-based medicinal chemistry to overcome the issues with the current series.