RESUMEN

INTRODUCTION: Benznidazole, the drug of choice for treating Chagas Disease (CD), has significant limitations, such as poor cure efficacy, mainly in the chronic phase of CD, association with side effects, and parasite resistance. Understanding parasite resistance to benznidazole is crucial for developing new drugs to treat CD. AREAS COVERED: Here, the authors review the current understanding of the molecular basis of benznidazole resistance. Furthermore, they discuss the state-of-the-art methods and critical outcomes employed to evaluate the efficacy of potential drugs against T. cruzi, aiming to select better compounds likely to succeed in the clinic. Finally, the authors describe the different strategies employed to overcome resistance to benznidazole and find effective new treatments for CD. EXPERT OPINION: Resistance to benznidazole is a complex phenomenon that occurs naturally among T. cruzi strains. The combination of compounds that inhibit different metabolic pathways of the parasite is an important strategy for developing a new chemotherapeutic protocol.

Asunto(s)

Enfermedad de Chagas , Descubrimiento de Drogas , Resistencia a Medicamentos , Nitroimidazoles , Tripanocidas , Trypanosoma cruzi , Trypanosoma cruzi/efectos de los fármacos , Nitroimidazoles/farmacología , Enfermedad de Chagas/tratamiento farmacológico , Enfermedad de Chagas/parasitología , Tripanocidas/farmacología , Humanos , Animales , Descubrimiento de Drogas/métodos , Desarrollo de Medicamentos

RESUMEN

The application of computer-aided drug discovery (CADD) approaches has enabled the discovery of new antimicrobial therapeutic agents in the past. The high prevalence of methicillin-resistantStaphylococcus aureus(MRSA) strains promoted this pathogen to a high-priority pathogen for drug development. In this sense, modern CADD techniques can be valuable tools for the search for new antimicrobial agents. We employed a combination of a series of machine learning (ML) techniques to select and evaluate potential compounds with antibacterial activity against methicillin-susceptible S. aureus (MSSA) and MRSA strains. In the present study, we describe the antibacterial activity of six compounds against MSSA and MRSA reference (American Type Culture Collection (ATCC)) strains as well as two clinical strains of MRSA. These compounds showed minimal inhibitory concentrations (MIC) in the range from 12.5 to 200 µM against the different bacterial strains evaluated. Our results constitute relevant proven ML-workflow models to distinctively screen for novel MRSA antibiotics.

Asunto(s)

Antibacterianos , Staphylococcus aureus Resistente a Meticilina , Antibacterianos/farmacología , Staphylococcus aureus , Meticilina/farmacología , Pruebas de Sensibilidad Microbiana

RESUMEN

INTRODUCTION: Chagas disease (CD) imposes social and economic burdens, yet the available treatments have limited efficacy in the disease's chronic phase and cause serious adverse effects. To address this challenge, target-based approaches are a possible strategy to develop new, safe, and active treatments for both phases of the disease. AREAS COVERED: This review delves into target-based approaches applied to CD drug discovery, emphasizing the studies from the last five years. We highlight the proteins cruzain (CZ), trypanothione reductase (TR), sterol 14 α-demethylase (CPY51), iron superoxide dismutase (Fe-SOD), proteasome, cytochrome b (Cytb), and cleavage and polyadenylation specificity factor 3 (CPSF3), chosen based on their biological and chemical validation as drug targets. For each, we discuss its biological relevance and validation as a target, currently related challenges, and the status of the most promising inhibitors. EXPERT OPINION: Target-based approaches toward developing potential CD therapeutics have yielded promising leads in recent years. We expect a significant advance in this field in the next decade, fueled by the new options for Trypanosoma cruzi genetic manipulation that arose in the past decade, combined with recent advances in computational chemistry and chemical biology.

Asunto(s)

Enfermedad de Chagas , Trypanosoma cruzi , Humanos , Enfermedad de Chagas/tratamiento farmacológico , Trypanosoma cruzi/genética , Descubrimiento de Drogas

RESUMEN

Chagas disease and Human African Trypanosomiasis, caused by Trypanosoma cruzi and T. brucei, respectively, pose relevant health challenges throughout the world, placing 65 to 70 million people at risk each. Given the limited efficacy and severe side effects associated with current chemotherapy, new drugs are urgently needed for both diseases. Here, we report the screening of the Pathogen Box collection against cruzain and TbrCatL, validated targets for Chagas disease and Human African Trypanosomiasis, respectively. Enzymatic assays were applied to screen 400 compounds, validate hits, determine IC50 values and, when possible, mechanisms of inhibition. In this case, 12 initial hits were obtained and ten were prioritized for follow-up. IC50 values were obtained for six of them (hit rate = 1.5%) and ranged from 0.46 ± 0.03 to 27 ± 3 µM. MMV687246 was found to be a mixed inhibitor of cruzain (Ki = 57 ± 6 µM) while MMV688179 was found to be a competitive inhibitor of cruzain with a nanomolar potency (Ki = 165 ± 63 nM). A putative binding mode for MMV688179 was obtained by docking. The six hits discovered against cruzain and TbrCatL are of great interest for further optimization by the medicinal chemistry community.

RESUMEN

Trypanosoma cruzi is a parasite that infects about 6-7 million people worldwide, mostly in Latin America, causing Chagas disease. Cruzain, the main cysteine protease of T. cruzi, is a validated target for developing drug candidates for Chagas disease. Thiosemicarbazones are one of the most relevant warheads used in covalent inhibitors targeting cruzain. Despite its relevance, the mechanism of inhibition of cruzain by thiosemicarbazones is unknown. Here, we combined experiments and simulations to unveil the covalent inhibition mechanism of cruzain by a thiosemicarbazone-based inhibitor (compound 1). Additionally, we studied a semicarbazone (compound 2), which is structurally similar to compound 1 but does not inhibit cruzain. Assays confirmed the reversibility of inhibition by compound 1 and suggested a two-step mechanism of inhibition. The Ki was estimated to be 36.3 µM and Ki* to be 11.5 µM, suggesting the pre-covalent complex to be relevant for inhibition. Molecular dynamics simulations of compounds 1 and 2 with cruzain were used to propose putative binding modes for the ligands. One-dimensional (1D) quantum mechanics/molecular mechanics (QM/MM) potential of mean force (PMF) and gas-phase energies showed that the attack of Cys25-S- on the C═S or C═O bond yields a more stable intermediate than the attack on the C═N bond of the thiosemicarbazone/semicarbazone. Two-dimensional (2D) QM/MM PMF revealed a putative reaction mechanism for compound 1, involving the proton transfer to the ligand, followed by the Cys25-S- attack at C═S. The ΔG and energy barrier were estimated to be -1.4 and 11.7 kcal/mol, respectively. Overall, our results shed light on the inhibition mechanism of cruzain by thiosemicarbazones.

Asunto(s)

Enfermedad de Chagas , Semicarbazonas , Tiosemicarbazonas , Trypanosoma cruzi , Humanos , Tiosemicarbazonas/química , Tiosemicarbazonas/farmacología , Cisteína Endopeptidasas/química , Proteínas Protozoarias/química , Inhibidores de Cisteína Proteinasa/química

RESUMEN

The Brazilian Compound Library (BraCoLi) is a novel open access and manually curated electronic library of compounds developed by Brazilian research groups to support further computer-aided drug design works, available on https://www.farmacia.ufmg.br/qf/downloads/ . Herein, the first version of the database is described comprising 1176 compounds. Also, the chemical diversity and drug-like profiles of BraCoLi were defined to analyze its chemical space. A significant amount of the compounds fitted Lipinski and Veber's rules, alongside other drug-likeness properties. A comparison using principal component analysis showed that BraCoLi is similar to other databases (FDA-approved drugs and NuBBEDB) regarding structural and physicochemical patterns. Furthermore, a scaffold analysis showed that BraCoLi presents several privileged chemical skeletons with great diversity. Despite the similar distribution in the structural and physicochemical spaces, Tanimoto coefficient values indicated that compounds present in the BraCoLi are generally different from the two other databases, where they showed different kernel distributions and low similarity. These facts show an interesting innovative aspect, which is a desirable feature for novel drug design purposes.

Asunto(s)

Diseño de Fármacos , Brasil , Bases de Datos Factuales

RESUMEN

Cryptococcus neoformans is a fungus responsible for infections in humans with a significant number of cases in immunosuppressed patients, mainly in underdeveloped countries. In this context, the thiazolylhydrazones are a promising class of compounds with activity against C. neoformans. The understanding of the structure-activity relationship of these derivatives could lead to the design of robust compounds that could be promising drug candidates for fungal infections. Specifically, modern techniques such as 4D-QSAR and machine learning methods were employed in this work to generate two QSAR models (one 2D and one 4D) with high predictive power (r2 for the test set equals to 0.934 and 0.831, respectively), and one random forest classification model was reported with Matthews correlation coefficient equals to 1 and 0.62 for internal and external validations, respectively. The physicochemical interpretation of selected models, indicated the importance of aliphatic substituents at the hydrazone moiety to antifungal activity, corroborating experimental data.Communicated by Ramaswamy H. Sarma.

Asunto(s)

Cryptococcus neoformans , Relación Estructura-Actividad Cuantitativa , Humanos , Antifúngicos/farmacología , Antifúngicos/química , Aprendizaje Automático

RESUMEN

RI76 is a novel 2-thiazolylhydrazone compound with reported antifungal activity. In preclinical drug development, it is fundamental to know the impurity profile and to understand degradation mechanisms of the molecule. In our study, RI76 was subjected to forced degradation conditions, and a stability-indicating HPLC-DAD method was developed and validated. Separation was carried out on a C18 column (150 × 4.6 mm i.d., 5 µm) maintained at 40°C using a 1 mL/min flow rate of 2 mM ammonium acetate with 0.1% formic acid (pH 3.0) and acetonitrile in gradient mode. The method was linear in the range of 0.7-91 µg/mL for RI76 and 0.7-25 µg/mL for its degradation product PD76. The formation of a major degradation product was quickly observed when RI76 was in aqueous solution. The chemical structure of this product, named PD76, was proposed based on LC-UV-MS experiments, synthesized in-house, and confirmed by NMR spectroscopy and chromatographic analysis. In vitro antifungal activity assays demonstrated that this resultant product shows a promising activity against clinically important Candida and Cryptococcus strains, matching or surpassing the activity of its precursor and of well-established antifungal drugs.

Asunto(s)

Antifúngicos/análisis , Antifúngicos/farmacología , Antifúngicos/química , Antifúngicos/farmacocinética , Candida/efectos de los fármacos , Cromatografía Líquida de Alta Presión/métodos , Cryptococcus/efectos de los fármacos , Estabilidad de Medicamentos , Límite de Detección , Modelos Lineales , Reproducibilidad de los Resultados

RESUMEN

Aim: All-trans retinoic acid (ATRA) shows erratic oral bioavailability when administered orally against leukemia, which can be solved through its incorporation in self-nanoemulsifying drug-delivery systems (SEDDS). The SEDDS developed contained a hydrophobic ion pair between benzathine (BZT) and ATRA and was enriched with tocotrienols by the input of a palm oil tocotrienol rich fraction (TRF) in its composition. Results: SEDDS-TRF-ATRA-BZT allowed the formation of emulsions with nanometric size that retained ATRA within their core after dispersion. Pharmacokinetic parameters after oral administration of SEDDS-TRF-ATRA-BZT in mice were improved compared with what was seen for an ATRA solution. Moreover, SEDDS-TRF-ATRA-BZT had improved activity against HL-60 cells compared with SEDDS without TRF. Conclusion: SEDDS-TRF-ATRA-BZT is a promising therapeutic choice over ATRA conventional medicine.

Asunto(s)

Sistemas de Liberación de Medicamentos , Tretinoina , Administración Oral , Animales , Disponibilidad Biológica , Emulsiones , Ratones

RESUMEN

Quantitative nuclear magnetic resonance (qNMR) is an analytical technique that offers numerous advantages in pharmaceutical applications including minimum sample preparation and rapid data collection times with no need for response factor corrections, being a powerful tool for assaying drug content in both drug discovery and early drug development. In the present work, we have applied qNMR, using both the internal standard and the electronic reference to access in vivo concentrations 2 calibration methods, to assess the purity of RI76, a novel antifungal drug candidate. NMR acquisition and processing parameters were optimized in order to obtain spectra with intense, well-resolved signals of completely relaxed nuclei. The analytical method was validated following current guidelines, demonstrating selectivity, linearity, accuracy, precision, and robustness. The calibration approaches were statistically compared, and no significant difference was observed when comparing the obtained results and their dispersion in terms of relative standard deviation. The proposed qNMR method may, therefore, be used for both qualitative and quantitative assessments of RI76 in early drug development and for characterization of this compound.

Asunto(s)

Antifúngicos/química , Espectroscopía de Resonancia Magnética/métodos , Tiazoles/química , Acetanilidas/química , Acetanilidas/normas , Calibración , Cromatografía Líquida de Alta Presión , Límite de Detección , Reproducibilidad de los Resultados

RESUMEN

Cryptococcosis is an opportunistic or primary fungal infection considered to be the most prevalent fatal fungal disease worldwide. Owing to the limited number of available drugs, it is necessary to search for novel antifungal compounds. In the present work, we assessed the antifungal efficacy of three thiazole derivatives (1, 2, and 3). We conducted in vitro and in vivo assays to investigate their effects on important virulence factors, such as capsule and biofilm formation. In addition, the phagocytosis index of murine macrophages exposed to compounds 1, 2, and 3 and the in vivo efficacy of 1, 2, and 3 in Galleria mellonella infected with Cryptococcus spp. were evaluated. All compounds exhibited antifungal activity against biofilms and demonstrated a reduction in biofilm metabolic activity by 43-50% for C. gattii and 26-42% for C. neoformans. Thiazole compounds promoted significant changes in the capsule thickness of C. gattii compared to that of C. neoformans. Further examination of these compounds suggests that they can improve the phagocytosis process of peritoneal murine macrophages in vitro, causing an increase in the phagocytosis rate. Survival percentage was examined in the invertebrate model Galleria mellonella larvae, and only compound 3 could increase the survival at doses of 5 mg/kg after infection with C. gattii (P = .0001) and C. neoformans (P = .0007), similar to fluconazole at 10 mg/kg. The results demonstrated that thiazole compounds, mainly compound 3, have potential to be used for future studies in the search for new therapeutics for cryptococcosis.

Asunto(s)

Antifúngicos/farmacología , Biopelículas/efectos de los fármacos , Criptococosis/microbiología , Cryptococcus/efectos de los fármacos , Cryptococcus/patogenicidad , Tiazoles/farmacología , Factores de Virulencia/antagonistas & inhibidores , Animales , Antifúngicos/química , Biopelículas/crecimiento & desarrollo , Células Cultivadas , Criptococosis/inmunología , Modelos Animales de Enfermedad , Polisacáridos Fúngicos/biosíntesis , Larva/microbiología , Larva/fisiología , Macrófagos/efectos de los fármacos , Macrófagos/microbiología , Ratones , Estructura Molecular , Mariposas Nocturnas , Fagocitosis/efectos de los fármacos , Análisis de Supervivencia , Tiazoles/química

RESUMEN

Candidiasis is an opportunistic fungal infection with Candida albicans being the most frequently isolated species. Treatment of these infections is challenging due to resistance that can develop during therapy, and the limited number of available antifungal compounds. Given this situation, the aim of this study was to evaluate the antifungal activity of four thiazolylhydrazone compounds against C. albicans. Thiazolylhydrazone compounds 1, 2, 3, and 4 were found to exert antifungal activity, with MICs of 0.125⁻16.0 µg/mL against C. albicans. The toxicity of the compounds was evaluated using human erythrocytes and yielded LC50 > 64 µg/mL. The compounds were further evaluated using the greater wax moth Galleria mellonella as an in vivo model. The compounds prolonged larval survival when tested between 5 and 15 mg/kg, performing as well as fluconazole. Compound 2 was evaluated in murine models of oral and systemic candidiasis. In the oral model, compound 2 reduced the fungal load on the mouse tongue; and in the systemic model it reduced the fungal burden found in the kidney when tested at 10 mg/kg. These results show that thiazolylhydrazones are an antifungal towards C. albicans with in vivo efficacy.

RESUMEN

OBJECTIVES: Candida albicans is a commensal organism and opportunistic pathogen associated both with superficial (mucosal and cutaneous) and systemic infections. Extensive use of antifungal agents has led to reduced susceptibility to the few existing drugs, which has encouraged the search for novel antifungal agents. Therefore, the present study investigated the antifungal activity of 2,6-bis[(E)-(4-pyridyl)methylidene]cyclohexanone (PMC) against C. albicans. METHODS: The in vitro activity of PMC was evaluated against C. albicans. Additionally, an invertebrate infection model in Caenorhabditis elegans as well as two infected murine models of oral and systemic candidiasis were used to determine the antifungal efficacy of PMC in vivo. RESULTS: Minimum inhibitory concentrations (MICs) of PMC ranged from 4-32µg/mL against nine clinical and two reference C. albicans isolates. Interestingly, PMC inhibited filamentation in vitro at subinhibitory concentrations similar to fluconazole. PMC also showed low toxicity against murine macrophages and human erythrocytes. In the invertebrate infection model, PMC was efficient in prolonging survival of C. elegans infected with C. albicans SC5314. Treatment with PMC was efficient both in murine models of systemic and oral candidiasis and was similar to that observed with conventional drug treatments (nystatin and fluconazole). CONCLUSIONS: The results of this study indicate the therapeutic potential of PMC as it was able to inhibit filamentation of C. albicans in vitro. These alterations to the fungi by PMC resulted in a reduction of oral and systemic infection in mice. In conclusion, we present promising evidence of the anticandidal activity of PMC in vitro and in vivo.

Asunto(s)

Antifúngicos/síntesis química , Candida albicans/efectos de los fármacos , Candidiasis/tratamiento farmacológico , Ciclohexanonas/síntesis química , Animales , Antifúngicos/química , Antifúngicos/farmacología , Caenorhabditis elegans , Ciclohexanonas/química , Ciclohexanonas/farmacología , Modelos Animales de Enfermedad , Farmacorresistencia Fúngica/efectos de los fármacos , Femenino , Fluconazol/farmacología , Humanos , Ratones , Pruebas de Sensibilidad Microbiana

RESUMEN

In the search for new antifungal agents, a novel series of fifteen hydrazine-thiazole derivatives was synthesized and assayed in vitro against six clinically important Candida and Cryptococcus species and Paracoccidioides brasiliensis. Eight compounds showed promising antifungal activity with minimum inhibitory concentration (MIC) values ranging from 0.45 to 31.2 µM, some of them being equally or more active than the drug fluconazole and amphotericin B. Active compounds were additionally tested for toxicity against human embryonic kidney (HEK-293) cells and none of them exhibited significant cytotoxicity, indicating high selectivity. Molecular modeling studies results corroborated experimental SAR results, suggesting their use in the design of new antifungal agents.

Asunto(s)

Antifúngicos/química , Antifúngicos/farmacología , Candida/efectos de los fármacos , Cryptococcus/efectos de los fármacos , Paracoccidioides/efectos de los fármacos , Tiazoles/química , Tiazoles/farmacología , Antifúngicos/síntesis química , Candidiasis/tratamiento farmacológico , Criptococosis/tratamiento farmacológico , Células HEK293 , Humanos , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Paracoccidioidomicosis/tratamiento farmacológico , Relación Estructura-Actividad , Tiazoles/síntesis química

RESUMEN

Chagas disease remains a major health problem in South America, and throughout the world. The two drugs clinically available for its treatment have limited efficacy and cause serious adverse effects. Cruzain is an established therapeutic target of Trypanosoma cruzi, the protozoan that causes Chagas disease. Our group recently identified a competitive cruzain inhibitor (compound 1) with an IC50 = 15 µM that is also more synthetically accessible than the previously reported lead, compound 2. Prior studies, however, did not propose a binding mode for compound 1, hindering understanding of the structure-activity relationship and optimization. Here, the cruzain binding mode of compound 1 was investigated using docking, molecular dynamics (MD) simulations with ab initio derived parameters, ab initio calculations, and MM/PBSA. Two ligand protonation states and four binding poses were evaluated. A careful ligand parameterization method was employed to derive more physically meaningful parameters than those obtained by automated tools. The poses of unprotonated 1 were unstable in MD, showing large conformational changes and diffusing away from the binding site, whereas the protonated form showed higher stability and interaction with negatively charged residues Asp161 and Cys25. MM/PBSA also suggested that these two residues contribute favorably to binding of compound 1. By combining results from MD, ab initio calculations, and MM/PBSA, a binding mode of 1 is proposed. The results also provide insights for further optimization of 1, an interesting lead compound for the development of new cruzain inhibitors.

Asunto(s)

Inhibidores de Cisteína Proteinasa/química , Modelos Moleculares , Proteínas Protozoarias/antagonistas & inhibidores , Quinolinas/química , Cisteína Endopeptidasas , Diseño de Fármacos , Ligandos , Estructura Molecular , Unión Proteica , Relación Estructura-Actividad , Termodinámica

RESUMEN

N-(2-butanoyloxyethyl)-4-(chloromethyl)-3-nitrobenzamide (NBCN) is a nitroaromatic bioreducible compound with cytotoxic effects in cancer cell lines. The aim of this work was to investigate the molecular mechanisms involved in cell death promoted by NBCN in HL60 cells. We observed that NBCN treatment increased intracellular ROS and reduced mitochondria membrane potential (ΔΨm). NBCN treatment also induced morphological changes, phosphatidylserine exposure, cell cycle arrest in G2/M-phase, DNA condensation and fragmentation, but it did not show cytotoxic effects on normal human peripheral blood mononuclear cells (PBMCs). NBCN-induced caspase 3- and 9-dependent DNA fragmentation, which was blocked by pretreatment with the broad-spectrum caspase inhibitor, z-VAD-fmk. Flow cytometry analysis demonstrated that NBCN also increased of the number of autophagic vesicles in HL60 cells, which was not observed when cells were pre-treated with bafilomycin A1. Taken together, these results indicate that NBCN triggered the mitochondrial apoptotic pathway and led to the onset of autophagic cell death, which contributed to its cytotoxic effects.

Asunto(s)

Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Benzamidinas/toxicidad , Clorometilcetonas de Aminoácidos/farmacología , Benzamidinas/química , Inhibidores de Caspasas/farmacología , Caspasas/metabolismo , Células Cultivadas , Fragmentación del ADN/efectos de los fármacos , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de los fármacos , Células HL-60 , Humanos , Leucocitos Mononucleares/citología , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/metabolismo , Puntos de Control de la Fase M del Ciclo Celular/efectos de los fármacos , Macrólidos/farmacología , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo

RESUMEN

Analogues of 8-chloro-N-(3-morpholinopropyl)-5H-pyrimido[5,4-b]indol-4-amine 1, a known cruzain inhibitor, were synthesized using a molecular simplification strategy. Five series of analogues were obtained: indole, pyrimidine, quinoline, aniline and pyrrole derivatives. The activity of the compounds was evaluated against the enzymes cruzain and rhodesain as well as against Trypanosoma cruzi amastigote and trypomastigote forms. The 4-aminoquinoline derivatives showed promising activity against both enzymes, with IC50 values ranging from 15 to 125µM. These derivatives were selective inhibitors for the parasitic proteases, being unable to inhibit mammalian cathepsins B and S. The most active compound against cruzain (compound 5a; IC50=15µM) is considerably more synthetically accessible than 1, while retaining its ligand efficiency. As observed for the original lead, compound 5a was shown to be a competitive enzyme inhibitor. In addition, it was also active against T. cruzi (IC50=67.7µM). Interestingly, the pyrimidine derivative 4b, although inactive in enzymatic assays, was highly active against T. cruzi (IC50=3.1µM) with remarkable selectivity index (SI=128) compared to uninfected fibroblasts. Both 5a and 4b exhibit drug-like physicochemical properties and are predicted to have a favorable ADME profile, therefore having great potential as candidates for lead optimization in the search for new drugs to treat Chagas disease.

Asunto(s)

Cisteína Endopeptidasas/efectos de los fármacos , Inhibidores de Cisteína Proteinasa/síntesis química , Inhibidores de Cisteína Proteinasa/farmacología , Proteínas Protozoarias/antagonistas & inhibidores , Inhibidores de Cisteína Proteinasa/química , Evaluación Preclínica de Medicamentos , Análisis Espectral/métodos , Trypanosoma cruzi/efectos de los fármacos , Trypanosoma cruzi/enzimología

RESUMEN

The pressing need for better drugs against Chagas disease, African sleeping sickness, and schistosomiasis motivates the search for inhibitors of cruzain, rhodesain, and Schistosoma mansoni CB1 (SmCB1), the major cysteine proteases from Trypanosoma cruzi, Trypanosoma brucei, and S. mansoni, respectively. Thiosemicarbazones and heterocyclic analogues have been shown to be both antitrypanocidal and inhibitory against parasite cysteine proteases. A series of compounds was synthesized and evaluated against cruzain, rhodesain, and SmCB1 through biochemical assays to determine their potency and structure-activity relationships (SAR). This approach led to the discovery of 6 rhodesain, 4 cruzain, and 5 SmCB1 inhibitors with 50% inhibitory concentrations (IC50s) of ≤ 10 µM. Among the compounds tested, the thiosemicarbazone derivative of peracetylated galactoside (compound 4i) was discovered to be a potent rhodesain inhibitor (IC50 = 1.2 ± 1.0 µM). The impact of a range of modifications was determined; removal of thiosemicarbazone or its replacement by semicarbazone resulted in virtually inactive compounds, and modifications in the sugar also diminished potency. Compounds were also evaluated in vitro against the parasites T. cruzi, T. brucei, and S. mansoni, revealing active compounds among this series.

Asunto(s)

Catepsina B/metabolismo , Cisteína Endopeptidasas/metabolismo , Inhibidores de Cisteína Proteinasa/síntesis química , Proteínas Protozoarias/metabolismo , Schistosoma mansoni/efectos de los fármacos , Schistosoma mansoni/enzimología , Tripanocidas/síntesis química , Animales , Inhibidores de Cisteína Proteinasa/química , Inhibidores de Cisteína Proteinasa/farmacología , Activación Enzimática/efectos de los fármacos , Tripanocidas/química , Tripanocidas/farmacología

RESUMEN

The nitroaromatic compound 4-bromomethyl-3-nitrobenzoic acid (ANB) is a promising antitumoral agent whose activity has recently been investigated. Forced degradation studies were conducted on ANB with a high-performance liquid chromatography-ultraviolet assay to establish its stability and selectivity. ANB was subjected to degradation studies under hydrolytic (acid and alkaline), oxidative and light exposition conditions. The compound showed greater lability only in acid and alkaline conditions by forming a major degradation product. The chromatographic separation of ANB and its degradation product was achieved on an octadecylsilane column using a mobile phase of methanol-water (80:20, v/v), pH 4.0 adjusted with formic acid, flow rate of 0.7 mL/min, ultraviolet diode array detection at λ 271 nm, injection volume of 20 µL and temperature of 30°C. The method was validated according to International Conference on Harmonization guidelines with respect to precision (average relative standard deviation 0.67%), accuracy (average 99.97%), linearity (y = 118730x + 12912; coefficient of determination > 0.999), specificity and robustness (p > 0.05). The degradation product formed as a result from the hydrolysis of nitrobenzyl bromide, corresponded to its benzyl alcohol, 4-hydroxymethyl-3-nitrobenzoic acid (ANOH) and was characterized by co-elution with a synthetic ANOH working standard.

Asunto(s)

Cromatografía Líquida de Alta Presión/métodos , Nitrobenzoatos/análisis , Nitrobenzoatos/química , Estabilidad de Medicamentos , Reproducibilidad de los Resultados

RESUMEN

Nitroheterocyclic compounds have received considerable interest as hypoxia-selective cytotoxins (HSC) for cancer treatment. In the present study, we investigated antitumor activity of an iodide analogue of metronidazole, 1-(2-iodoethyl)-2-methyl-5-nitroimidazole (MTZ-I), using Swiss mice bearing solid Ehrlich tumor. MTZ-I showed potent anti-cancer activity at a dose of 40 mg/kg. MTZ-I loaded solid lipid nanoparticles (SLN) were developed as an alternative colloidal carrier system to enhance tumor drug uptake. SLN were characterized for particle size, polydispersity index, zeta potential and entrapment efficiency. In addition, the influence of presence of the cationic lipid stearylamine (STE) on stability of formulation was assessed. The results of DSC study showed that MTZ-I exhibited interaction with STE.

Asunto(s)

Carcinoma de Ehrlich/tratamiento farmacológico , Carcinoma de Ehrlich/patología , Lípidos/química , Metronidazol/análogos & derivados , Metronidazol/administración & dosificación , Nanocápsulas/administración & dosificación , Nanocápsulas/química , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/química , Línea Celular Tumoral , Difusión , Ratones , Nanocápsulas/ultraestructura , Tamaño de la Partícula , Resultado del Tratamiento