1,3-Thiazole derivatives as privileged structures for anti-Trypanosoma cruzi activity: Rational design, synthesis, in silico and in vitro studies

Recent Progress in Thiazole, Thiosemicarbazone, and Semicarbazone Derivatives as Antiparasitic Agents Against Trypanosomatids and Plasmodium spp

Neglected tropical diseases (NTDs), including Chagas disease, human African trypanosomiasis (HAT), leishmaniasis, and malaria, remain a major global health challenge, disproportionately affecting low-income populations. Current therapies for these diseases suffer from significant limitations, such as reduced efficacy, high toxicity, and emerging parasite resistance, highlighting the urgent need for new therapeutic strategies. In response, substantial efforts have been directed toward the synthesis of new molecules with improved potency, selectivity, and pharmacokinetic profiles. However, despite many of these compounds exhibiting favorable ADMET (absorption, distribution, metabolism, excretion, and toxicity) profiles and strong in vitro activity, their translation into in vivo models remains limited. Key challenges include the lack of investment, the absence of fully representative experimental models, and difficulties in extrapolating cell-based assay results to more complex biological systems. In this review, we analyzed the latest advancements (2019-2024) in the development of these compound classes, correlating predictive parameters with their observed biological activity. Among these parameters, we highlighted the partition coefficient (LogP), which measures a compound's lipophilicity and influences its ability to cross biological membranes, and Caco-2 cell permeability, an in vitro model widely used to predict intestinal drug absorption. Additionally, we prioritized the most promising molecules and structural classes for pharmaceutical development, discussing structure-activity relationships (SARs) and the remaining challenges that must be overcome to enable the clinical application of these compounds in the treatment of NTDs.

Design, Synthesis, and In Silico Molecular Docking Studies of Adamantanyl Hydrazinylthiazoles as Potential Antidiabetic Agents

Diabetes mellitus (DM) is a widespread disease that poses a major threat to millions of people. To address this issue, we have synthesized seventeen new 4-(adamantan-1-yl)-(2-(arylidene)hydrazinyl)thiazoles (3a-q) via Hantzsch synthetic approach. The molecular structures of all the compounds were confirmed using FT-IR, 1H- and 13C-NMR spectroscopy, and HR-mass spectrometry. Protein kinase, α-amylase, glycation, and oxidation inhibition potential of all compounds were also investigated, and it was found that compounds 3b, 3c, 3e-3g, and 3i-3q have shown excellent α-amylase inhibition (IC50 = 7.91 ± 0.07 to 28.57 ± 0.1 µM), compounds 3c, 3e, 3i, 3k, and 3p (IC50 = 30.6 ± 0.06 to 37.8 ± 0.005 ppm) were found to be highly potent anti-glycating agents, and compounds 3c, 3g, 3h, 3k, and 3m were found to be more potent protein kinase inhibitors as compared to standards. The compounds 3b, 3c, 3d, 3e, 3f, 3g, 3i, 3k, 3l, 3m, 3n, 3p, and 3q have shown good antioxidant potential (IC50 = 27.5 ± 0.09 to 48.8 ± 0.09 µM) as compared to standard ascorbic acid (IC50 = 51.3 ± 0.1 µM). The biocompatibility of all samples was also tested by employing brine shrimp lethality and in vitro hemolytic assays and was found to be safe to human erythrocytes at tested concentrations. Furthermore, the molecular docking simulation study also revealed that almost all synthesized compounds have potential interactions with target proteins at the molecular level.

Synthesis and Biological Evaluation of New Chalcogen Semicarbazone (S, Se) and Their Azole Derivatives against Chagas Disease

Chagas disease is caused by the eukaryote parasite Trypanosoma cruzi. Current treatment exhibits limited efficacy and selenium-based compounds emerged as promising candidates for new therapies which is surpassing its bioisoster, sulfur. We designed new thiosemicarbazones, thiazoles, selenosemicarbazones and selenazoles, using isosteric substitution. We synthesized 57 new chalcogen compounds which were evaluated against T. cruzi, C2C12 cells and cruzain, the main target of this parasite. Additionally, human cathepsin L, was tested for selectivity. Three compounds were selected, based on their activity against the intracellular amastigotes (EC50 < 1 μM, SI > 10) and cruzain (IC50 < 100 nM, SI > 5.55) which compared favorably with the approved drug, Benznidazole, and the well-established cruzain inhibitor K777. Seleno-compounds demonstrated enhanced activity and selenazoles showed a decrease in selenium-associated toxicity. Compound 4-methyl-2-(2-(1-(3-nitrophenyl)ethylidene)hydrazineyl)-1,3-selenazole (Se2h) emerged as a promising candidate, and its binding to cruzain was investigated. Pharmacokinetic assessment was conducted, showing a favorable profile for subsequent in vivo assays.

DNA G-quadruplexes in the genome of Trypanosoma cruzi as potential therapeutic targets for Chagas disease: Dithienylethene ligands as effective antiparasitic agents

Chagas disease is caused by the parasite Trypanosoma cruzi and affects over 7 million people worldwide. The two actual treatments, Benznidazole (Bzn) and Nifurtimox, cause serious side effects due to their high toxicity leading to treatment abandonment by the patients. In this work, we propose DNA G-quadruplexes (G4) as potential therapeutic targets for this infectious disease. We have found 174 PQS per 100,000 nucleotides in the genome of T. cruzi and confirmed G4 formation of three frequent motifs. We synthesized a family of 14 quadruplex ligands based in the dithienylethene (DTE) scaffold and demonstrated their binding to these identified G4 sequences. Several DTE derivatives exhibited micromolar activity against epimastigotes of four different strains of T. cruzi, in the same concentration range as Bzn. Compounds L3 and L4 presented remarkable activity against trypomastigotes, the active form in blood, of T. cruzi SOL strain (IC50 = 1.5-3.3 μM, SI = 25-40.9), being around 40 times more active than Bzn and displaying much better selectivity indexes.

Trypanosoma cruzi killing and immune response boosting by novel phenoxyhydrazine-thiazole against Chagas disease

Trypanosoma cruzi (T. cruzi) causes Chagas, which is a neglected tropical disease (NTD). WHO estimates that 6 to 7 million people are infected worldwide. Current treatment is done with benznidazole (BZN), which is very toxic and effective only in the acute phase of the disease. In this work, we designed, synthesized, and characterized thirteen new phenoxyhydrazine-thiazole compounds and applied molecular docking and in vitro methods to investigate cell cytotoxicity, trypanocide activity, nitric oxide (NO) production, cell death, and immunomodulation. We observed a higher predicted affinity of the compounds for the squalene synthase and 14-alpha demethylase enzymes of T. cruzi. Moreover, the compounds displayed a higher predicted affinity for human TLR2 and TLR4, were mildly toxic in vitro for most mammalian cell types tested, and LIZ531 (IC50 2.8 μM) was highly toxic for epimastigotes, LIZ311 (IC50 8.6 μM) for trypomastigotes, and LIZ331 (IC50 1.9 μM) for amastigotes. We observed that LIZ311 (IC50 2.5 μM), LIZ431 (IC50 4.1 μM) and LIZ531 (IC50 5 μM) induced 200 μg/mL of NO and JM14 induced NO production in three different concentrations tested. The compound LIZ331 induced the production of TNF and IL-6. LIZ311 induced the secretion of TNF, IFNγ, IL-2, IL-4, IL-10, and IL-17, cell death by apoptosis, decreased acidic compartment formation, and induced changes in the mitochondrial membrane potential. Taken together, LIZ311 is a promising anti-T. cruzi compound is not toxic to mammalian cells and has increased antiparasitic activity and immunomodulatory properties.

Structural investigation of Trypanosoma cruzi Akt-like kinase as drug target against Chagas disease

According to the World Health Organization, Chagas disease (CD) is the most prevalent poverty-promoting neglected tropical disease. Alarmingly, climate change is accelerating the geographical spreading of CD causative parasite, Trypanosoma cruzi, which additionally increases infection rates. Still, CD treatment remains challenging due to a lack of safe and efficient drugs. In this work, we analyze the viability of T. cruzi Akt-like kinase (TcAkt) as drug target against CD including primary structural and functional information about a parasitic Akt protein. Nuclear Magnetic Resonance derived information in combination with Molecular Dynamics simulations offer detailed insights into structural properties of the pleckstrin homology (PH) domain of TcAkt and its binding to phosphatidylinositol phosphate ligands (PIP). Experimental data combined with Alpha Fold proposes a model for the mechanism of action of TcAkt involving a PIP-induced disruption of the intramolecular interface between the kinase and the PH domain resulting in an open conformation enabling TcAkt kinase activity. Further docking experiments reveal that TcAkt is recognized by human inhibitors PIT-1 and capivasertib, and TcAkt inhibition by UBMC-4 and UBMC-6 is achieved via binding to TcAkt kinase domain. Our in-depth structural analysis of TcAkt reveals potential sites for drug development against CD, located at activity essential regions.