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1.
J Enzyme Inhib Med Chem ; 35(1): 21-30, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-31619095

RESUMO

Trypanosoma cruzi carbonic anhydrase (TcCA) has recently emerged as an interesting target for the design of new compounds to treat Chagas disease. In this study we report the results of a structure-based virtual screening campaign to identify novel and selective TcCA inhibitors. The combination of properly validated computational methodologies such as comparative modelling, molecular dynamics and docking simulations allowed us to find high potency hits, with KI values in the nanomolar range. The compounds also showed trypanocidal effects against T. cruzi epimastigotes and trypomastigotes. All the candidates are selective for inhibiting TcCA over the human isoform CA II, which is encouraging in terms of possible therapeutic safety and efficacy.


Assuntos
Inibidores da Anidrase Carbônica/farmacologia , Anidrases Carbônicas/metabolismo , Doença de Chagas/tratamento farmacológico , Ciclamatos/farmacologia , Tripanossomicidas/farmacologia , Inibidores da Anidrase Carbônica/síntese química , Inibidores da Anidrase Carbônica/química , Doença de Chagas/metabolismo , Ciclamatos/síntese química , Ciclamatos/química , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Humanos , Modelos Moleculares , Estrutura Molecular , Testes de Sensibilidade Parasitária , Relação Estrutura-Atividade , Tripanossomicidas/síntese química , Tripanossomicidas/química , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/enzimologia
4.
Chem Biodivers ; 16(11): e1900359, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31544347

RESUMO

The objective of this study was to evaluate the chemical composition, and the trypanocidal and antibacterial activities of the essential oils from four species of Annonaceae: Bocageopsis multiflora (Mart.) R.E.Fr., Duguetia quitarensis Benth., Fusaea longifolia (Aubl.) Saff., and Guatteria punctata (Aubl.) R.A.Howard. The chemical composition of the essential oils from the aerial parts yielded 23, 20, 21 and 23 constituents, respectively, which were identified by GC/MS. The trypanocidal activity was evaluated against the amastigote and trypomastigote forms of T. cruzi. The antibacterial activity was evaluated by the microdilution method against enterohemorrhagic Escherichia coli, Pseudomonas aeruginosa, Streptococcus mutans, Streptococcus pyogenes, and methicillin-resistant Staphylococcus aureus. The results of trypanocidal activity showed that the essential oils of the four species were active at the tested concentrations, with G. punctata essential oil being the most active, with IC50 =0.029 µg/mL, and selectivity index (SI)=32, being 34 times more active than the reference drug benznidazole. All EOs showed strong antibacterial activity (minimum inhibitory concentrations of 4.68-37.5 µg/mL) against strains of S. mutans.


Assuntos
Annonaceae/química , Antibacterianos/farmacologia , Óleos Voláteis/farmacologia , Tripanossomicidas/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Testes de Sensibilidade Parasitária , Pseudomonas aeruginosa/efeitos dos fármacos , Especificidade da Espécie , Streptococcus mutans/efeitos dos fármacos , Streptococcus pyogenes/efeitos dos fármacos , Tripanossomicidas/química , Tripanossomicidas/isolamento & purificação , Trypanosoma cruzi/efeitos dos fármacos
5.
Molecules ; 24(18)2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31487860

RESUMO

Leishmanicidal drugs have many side effects, and drug resistance to all of them has been documented. Therefore, the development of new drugs and the identification of novel therapeutic targets are urgently needed. Leishmania mexicana trypanothione reductase (LmTR), a NADPH-dependent flavoprotein oxidoreductase important to thiol metabolism, is essential for parasite viability. Its absence in the mammalian host makes this enzyme an attractive target for the development of new anti-Leishmania drugs. Herein, a tridimensional model of LmTR was constructed and the molecular docking of 20 molecules from a ZINC database was performed. Five compounds (ZINC04684558, ZINC09642432, ZINC12151998, ZINC14970552, and ZINC11841871) were selected (docking scores -10.27 kcal/mol to -5.29 kcal/mol and structurally different) and evaluated against recombinant LmTR (rLmTR) and L. mexicana promastigote. Additionally, molecular dynamics simulation of LmTR-selected compound complexes was achieved. The five selected compounds inhibited rLmTR activity in the range of 32.9% to 40.1%. The binding of selected compounds to LmTR involving different hydrogen bonds with distinct residues of the molecule monomers A and B is described. Compound ZINC12151998 (docking score -10.27 kcal/mol) inhibited 32.9% the enzyme activity (100 µM) and showed the highest leishmanicidal activity (IC50 = 58 µM) of all the selected compounds. It was more active than glucantime, and although its half-maximal cytotoxicity concentration (CC50 = 53 µM) was higher than that of the other four compounds, it was less cytotoxic than amphotericin B. Therefore, compound ZINC12151998 provides a promising starting point for a hit-to-lead process in our search for new anti-Leishmania drugs that are more potent and less cytotoxic.


Assuntos
Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Leishmania mexicana/efeitos dos fármacos , Leishmania mexicana/enzimologia , NADH NADPH Oxirredutases/antagonistas & inibidores , NADH NADPH Oxirredutases/química , Tripanossomicidas/química , Tripanossomicidas/farmacologia , Sequência de Aminoácidos , Sítios de Ligação , Relação Dose-Resposta a Droga , Ligações de Hidrogênio , Conformação Molecular , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Estrutura Molecular , Farmacocinética , Proteínas Recombinantes/química , Relação Estrutura-Atividade
6.
Exp Parasitol ; 206: 107730, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31494215

RESUMO

Phospholipids are the main component of membranes and are responsible for cell integrity. Alkylphospholipid analogues (APs) were first designed as antitumoral agents and were later tested against different cell types. Trypanosoma cruzi, the Chagas disease etiological agent, is sensitive to APs (edelfosine, miltefosine and ilmofosine) in vitro. We investigated the effect of synthetic ring substituted AP against epimastigotes, amastigotes and trypomastigotes. TCAN26, could inhibit the in vitro growth of epimastigotes and amastigotes with the 50% inhibitory concentrations (IC50) in the nanomolar range. Trypomastigotes lysis was also induced with 24-h treatment and a LC50 of 2.3 µM. Ultrastructural analysis by electron microscopy demonstrated that TCAN26 mainly affected the parasite's membranes leading to mitochondrial and Golgi cisternae swelling, membrane blebs, and autophagic figures in the different parasite developmental stages. While the Golgi of the parasites was significantly affected, the Golgi complex of the host cells remained normal suggesting a specific mechanism of action. In summary, our results suggest that TCAN 26 is a potent and selective inhibitor of T. cruzi growth probably due to disturbances of phospholipid biosynthesis.


Assuntos
Adamantano/farmacologia , Fosforilcolina/análogos & derivados , Fosforilcolina/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Adamantano/química , Animais , Antiprotozoários/química , Antiprotozoários/farmacologia , Autofagia/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Relação Dose-Resposta a Droga , Citometria de Fluxo , Complexo de Golgi/efeitos dos fármacos , Concentração Inibidora 50 , Dose Letal Mediana , Macrófagos Peritoneais/efeitos dos fármacos , Camundongos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Microscopia Imunoeletrônica , Mitocôndrias/efeitos dos fármacos , Fosforilcolina/química , Tripanossomicidas/química , Trypanosoma cruzi/crescimento & desenvolvimento , Trypanosoma cruzi/ultraestrutura
7.
Eur J Med Chem ; 182: 111610, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31434040

RESUMO

Drug therapy for Chagas disease remains a major challenge as potential candidate drugs have failed clinical trials. Currently available drugs have limited efficacy and induce serious side effects. Thus, the discovery of new drugs is urgently needed in the fight against Chagas' disease. Here, we synthesized and evaluated the biological effect of pyrazole-imidazoline (1a-i) and pyrazole-tetrahydropyrimidine (2a-i) derivatives against relevant clinical forms of Trypanosoma cruzi. The structure-activity relationship (SAR), drug-target search, physicochemical and ADMET properties of the major active compounds in vitro were also assessed in silico. Pyrazole derivatives showed no toxicity in Vero cells and also no cardiotoxicity. Phenotypic screening revealed two dichlorinated pyrazole-imidazoline derivatives (1c and 1d) with trypanocidal activity higher than that of benznidazole (Bz) against trypomastigotes; these were also the most potent compounds against intracellular amastigotes. Replacement of imidazoline with tetrahydropyrimidine in the pyrazole compounds completely abolished the trypanocidal activity of series 2(a-i) derivatives. The physicochemical and ADMET properties of the compounds predicted good permeability, good oral bioavailability, no toxicity and mutagenicity of 1c and 1d. Pyrazole nucleus had high frequency hits for cruzipain in drug-target search and structure activity relationship (SAR) analysis of pyrazole-imidazoline derivatives revealed enhanced activity when chlorine atom was inserted in meta-positions of the benzene ring. Additionally, we found evidence that both compounds (1c and 1d) have the potential to interact non-covalently with the active site of cruzipain and also inhibit the cysteine proteinase activity of T. cruzi. Collectively, the data presented here reveal pyrazole derivatives with promise for further optimization in the therapy of Chagas disease.


Assuntos
Doença de Chagas/tratamento farmacológico , Imidazolinas/farmacologia , Pirazóis/farmacologia , Pirimidinas/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Células Cultivadas , Relação Dose-Resposta a Droga , Humanos , Imidazolinas/química , Estrutura Molecular , Testes de Sensibilidade Parasitária , Pirazóis/química , Pirimidinas/química , Relação Estrutura-Atividade , Tripanossomicidas/síntese química , Tripanossomicidas/química , Células Vero
9.
Eur J Med Chem ; 180: 191-203, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31306906

RESUMO

Chagas disease is an illness caused by the protozoan parasite Trypanosoma cruzi. The current chemotherapy is based on benznidazole, and, in some countries, Nifurtimox, which is effective in the acute phase of the disease, but its efficacy in the chronic phase remains controversial. It can also cause serious side effects that lead sufferers to abandon treatment. In the present work, is reported the synthesis and trypanocidal activity of new 2-(phenylthio)ethylidene thiosemicarbazones (4-15) and 1,3-thiazoles (16-26). The cyclization of thiosemicarbazones into 1,3-thiazoles presents an improvement in the cytotoxic profile for T. cruzi parasite, denoting selective compounds. Compound 18 was identified as the most promising of all compounds tested, showing an IC50 of 2.6 µM for the trypomastigote form and a non-cytotoxic effect on mouse spleen cells, reaching a selective index of 95.1. Among the 22 compounds tested, six compounds present a better trypanocidal activity, and five compounds have an equipotent activity compared to benznidazole. Flow cytometry and ultrastructural analysis were performed and indicate that compound 18 causes parasite cell death through apoptosis and acts via an autophagic pathway.


Assuntos
Desenho de Drogas , Tiazóis/farmacologia , Tiossemicarbazonas/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Relação Dose-Resposta a Droga , Estrutura Molecular , Testes de Sensibilidade Parasitária , Relação Estrutura-Atividade , Tiazóis/síntese química , Tiazóis/química , Tiossemicarbazonas/síntese química , Tiossemicarbazonas/química , Tripanossomicidas/síntese química , Tripanossomicidas/química
10.
Eur J Med Chem ; 180: 213-223, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31306908

RESUMO

Reactions of Ni(II) and Pd(II) precursors with S-benzyl-N-(ferrocenyl)methylenedithiocarbazate (HFedtc) led to the formation of heterobimetallic complexes of the type [MII(Fedtc)2] (M = Ni and Pd). The characterization of the compounds involved the determination of melting point, FTIR, UV-Vis, 1H NMR, elemental analysis and electrochemical experiments. Furthermore, the crystalline structures of HFedtc and [NiII(Fedtc)2] were determined by single crystal X-ray diffraction. The compounds were evaluated against the intracellular form of Trypanosoma cruzi (Tulahuen Lac-Z strain) and the cytotoxicity assays were assessed using LLC-MK2 cells. The results showed that the coordination of HFedtc to Ni(II) or Pd(II) decreases the in vitro trypanocidal activity while the cytotoxicity against LLC-MK2 cells does not change significantly. [PdII(Fedtc)2] showed the greater potential between the two complexes studied, showing an SI value of 8.9. However, this value is not better than that of the free ligand with an SI of 40, a similar value to that of the standard drug benznidazole (SI = 48). Additionally, molecular docking simulations were performed with Trypanosoma cruzi Old Yellow Enzyme (TcOYE), which predicted that HFedtc binds to the protein, almost parallel to the flavin mononucleotide (FMN) prosthetic group, while the [NiII(Fedtc)2] complex was docked into the enzyme binding site in a significantly different manner. In order to confirm the hypothetical interaction, in vitro experiments of fluorescence quenching and enzymatic activity were performed which indicated that, although HFedtc was not processed by the enzyme, it was able to act as a competitive inhibitor, blocking the hydride transfer from the FMN prosthetic group of the enzyme to the menadione substrate.


Assuntos
Compostos de Benzil/farmacologia , Complexos de Coordenação/farmacologia , Inibidores Enzimáticos/farmacologia , Hidrazinas/farmacologia , Metalocenos/farmacologia , NADPH Desidrogenase/antagonistas & inibidores , Níquel/farmacologia , Paládio/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/química , Complexos de Coordenação/metabolismo , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Humanos , Hidrazinas/química , Macaca mulatta , Metalocenos/química , Simulação de Acoplamento Molecular , Estrutura Molecular , NADPH Desidrogenase/química , NADPH Desidrogenase/metabolismo , Níquel/química , Níquel/metabolismo , Paládio/química , Paládio/metabolismo , Relação Estrutura-Atividade , Tripanossomicidas/química , Tripanossomicidas/metabolismo , Trypanosoma cruzi/metabolismo
11.
Inorg Chem ; 58(15): 10129-10138, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31310108

RESUMO

A series of 16 "3 + 2" mixed-ligand complexes of the general composition [ReO(L1)(L2)] (H2L1a-H2L1d = tridentate thiosemicarbazones having a phenyl group with 4-H, 4-F, 3,5-di-F, and 4-CF3 substituents; HL2a-HL2d = bidentate N,N-diethyl-N'-benzoylthioureas with 4-H, 4-F, 3,5-di-F, and 4-CF3 substituents at the benzoyl groups) have been synthesized and characterized by spectroscopic methods and X-ray diffraction. Irrespective of the individual fluorine substitution, the complexes are stable and possess the same general structure. Some systematic electronic effects of the fluorine-substitution patterns of the ligands have been found on the 13C NMR chemical shifts of the N-C═N carbon atoms of the {L1}2- and the C═O carbon atoms of the {L2}- ligands. Antiparasitic properties of the rhenium complexes have been tested against epimastigotes and trypomastigotes forms of two Trypanosoma cruzi strains and the amastigotes form of one of them. The results of this study indicate that the activity of the rhenium complexes can clearly be modulated by fluorine substitution of their ligands. Some of the fluorinated compounds show a high activity against epimastigotes and trypomastigotes forms of the parasites. Reactions between (NBu4)[TcOCl4] and two representatives of the fluorinated ligands (H2L1b, 4-F-substituted, and H2L1c, 4-CF3-substituted) form stable complexes of the composition [TcOCl(L1b)] and [TcOCl(L1c)]. Subsequent reactions of these products with HL2b (4-F-substituted) give the corresponding [TcO(L1)(L2)] mixed-ligand complexes. Also, the technetium compounds are stable as solids and in solutions and have structures corresponding to those of their rhenium analogues.


Assuntos
Complexos de Coordenação/farmacologia , Halogenação , Rênio/farmacologia , Tiossemicarbazonas/farmacologia , Tioureia/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Cristalografia por Raios X , Haplorrinos , Ligantes , Modelos Moleculares , Estrutura Molecular , Testes de Sensibilidade Parasitária , Rênio/química , Tiossemicarbazonas/química , Tioureia/química , Tripanossomicidas/síntese química , Tripanossomicidas/química
12.
Eur J Med Chem ; 179: 765-778, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31284086

RESUMO

Chagas disease, Human African Trypanosomiasis, and schistosomiasis are neglected parasitic diseases for which new treatments are urgently needed. To identify new chemical leads, we screened the 400 compounds of the Open Access Malaria Box against the cysteine proteases, cruzain (Trypanosoma cruzi), rhodesain (Trypanosoma brucei) and SmCB1 (Schistosoma mansoni), which are therapeutic targets for these diseases. Whereas just three hits were observed for SmCB1, 70 compounds inhibited cruzain or rhodesain by at least 50% at 5 µM. Among those, 15 commercially available compounds were selected for confirmatory assays, given their potency, time-dependent inhibition profile and reported activity against parasites. Additional assays led to the confirmation of four novel classes of cruzain and rhodesain inhibitors, with potency in the low-to mid-micromolar range against enzymes and T. cruzi. Assays against mammalian cathepsins S and B revealed inhibitor selectivity for parasitic proteases. For the two competitive inhibitors identified (compounds 7 and 12), their binding mode was predicted by docking, providing a basis for structure-based optimization efforts. Compound 12 also acted directly against the trypomastigote and the intracellular amastigote forms of T. cruzi at 3 µM. Therefore, through a combination of experimental and computational approaches, we report promising hits for optimization in the development of new trypanocidal drugs.


Assuntos
Cisteína Proteases/metabolismo , Inibidores de Cisteína Proteinase/farmacologia , Descoberta de Drogas , Malária/tratamento farmacológico , Schistosoma mansoni/metabolismo , Tripanossomicidas/farmacologia , Animais , Inibidores de Cisteína Proteinase/síntese química , Inibidores de Cisteína Proteinase/química , Relação Dose-Resposta a Droga , Malária/metabolismo , Estrutura Molecular , Testes de Sensibilidade Parasitária , Schistosoma mansoni/efeitos dos fármacos , Relação Estrutura-Atividade , Tripanossomicidas/síntese química , Tripanossomicidas/química , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/metabolismo , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/metabolismo
13.
Mem Inst Oswaldo Cruz ; 114: e190017, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31271593

RESUMO

BACKGROUND: Only benznidazole (Bnz) (1) and nifurtimox (Nfx) (2) are licensed for the treatment of Chagas disease although their safety and efficacy profile are far from ideal. Farmanguinhos from Fiocruz has developed seven nitroimidazole compounds (4-10) analogs of megazol (3). OBJECTIVES: To evaluate whether the genotoxic effect of 3 was abolished in the seven nitroimidazoles (4-10) analogs using the in vitro alkaline comet assay (CA) and the in vitro cytokinesis-block micronucleus assay (CBMN) in whole human blood cells (WHBC) and correlate this effect with their trypanocidal activity using bloodstream trypomastigote forms of Trypanosoma cruzi. METHODS: The toxicity of 3-10 to WHBC in the in vitro CA was determined using the fluorescein diacetate/ethidium bromide assay. DNA damage in the in vitro CA was evaluated according to tail size in four classes (0-3) and methyl methane-sulfonate (MMS) was used as a positive control. The cytotoxicity of 3-10 to WHBC in the CBMN was measured using the cytokinesis-block proliferation index and the replication index. The number of the micronucleate cells in 2,000 binucleate cells by experimental group was determined. Mitomycin C and N-deacetyl-N-methylcolchicine were used as positive controls. FINDINGS: Compound 3 showed a significant DNA strand break effect through the in vitro CA and highly significant clastogenic and/or aneugenic effect in the CBMN. Compounds 5, 6, 8, 9 and 10 showed negative results in the CBMN and positive results in the in vitro CA, while the inverse effect was observed for 4 and 7. MAIN CONCLUSIONS: Compound 10 was the most promising to proceed with the development as a drug candidate in the treatment of Chagas disease showing absence of chromosomal cytogenetic damage and high activity against T. cruzi, about two times higher than 3 and the clinical drug 1.


Assuntos
Nitroimidazóis/toxicidade , Tripanossomicidas/toxicidade , Células Sanguíneas/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaio Cometa/métodos , Dano ao DNA , Humanos , Testes para Micronúcleos/métodos , Nifurtimox/química , Nifurtimox/toxicidade , Nitroimidazóis/química , Valores de Referência , Reprodutibilidade dos Testes , Tiadiazóis/química , Tiadiazóis/toxicidade , Fatores de Tempo , Tripanossomicidas/química , Trypanosoma cruzi/efeitos dos fármacos
14.
Acta Trop ; 198: 105080, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31299283

RESUMO

Neglected tropical diseases (NTDs) constitute a group of infectious diseases prevalent in countries with tropical and subtropical climate that affect the poorest individuals and produce high chronic disability associated with serious problems for the health system and socioeconomic development. Chagas disease or American trypanosomiasis is included on the NTDs list. However, even though this disease affects more than 10 million people, mostly in Latin America, causing the death of over 10,000 people every year, only two drugs are approved for its treatment, benznidazole and nifurtimox. These antiparasitic agents were developed almost half a century ago and present several biopharmaceutical disadvantages such as low aqueous solubility and permeability limiting their bioavailability. In addition, both therapeutic agents are available only as tablets and a liquid pediatric formulation is still lacking. Therefore, novel pharmaceutical strategies to optimize the pharmacotherapy of Chagas disease are urgently required. In this regard, nanotechnological approaches may be a crucial alternative for the delivery of both drugs ensuring an effective pharmacotherapy although the successful bench-to-bedside translation remains a major challenge. The present work reviews in detail the formulation and in-vitro/in-vivo analysis of different nanoformulations of nifurtimox and benznidazole in order to enhance their solubility, dissolution, bioavailability and trypanocidal activity.


Assuntos
Doença de Chagas/tratamento farmacológico , Nanoestruturas , Nifurtimox/uso terapêutico , Nitroimidazóis/uso terapêutico , Tripanossomicidas/uso terapêutico , Formas de Dosagem , Humanos , Nifurtimox/administração & dosagem , Nifurtimox/química , Nitroimidazóis/administração & dosagem , Nitroimidazóis/química , Tripanossomicidas/administração & dosagem , Tripanossomicidas/química
15.
Int J Mol Sci ; 20(11)2019 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-31181717

RESUMO

Small-molecule compounds that have promising activity against macromolecular targets from Trypanosoma cruzi occasionally fail when tested in whole-cell phenotypic assays. This outcome can be attributed to many factors, including inadequate physicochemical and pharmacokinetic properties. Unsuitable physicochemical profiles usually result in molecules with a poor ability to cross cell membranes. Quantitative structure-activity relationship (QSAR) analysis is a valuable approach to the investigation of how physicochemical characteristics affect biological activity. In this study, artificial neural networks (ANNs) and kernel-based partial least squares regression (KPLS) were developed using anti-T. cruzi activity data for broadly diverse chemotypes. The models exhibited a good predictive ability for the test set compounds, yielding q2 values of 0.81 and 0.84 for the ANN and KPLS models, respectively. The results of this investigation highlighted privileged molecular scaffolds and the optimum physicochemical space associated with high anti-T. cruzi activity, which provided important guidelines for the design of novel trypanocidal agents having drug-like properties.


Assuntos
Aprendizado de Máquina , Relação Quantitativa Estrutura-Atividade , Tripanossomicidas/química , Trypanosoma cruzi/efeitos dos fármacos , Tripanossomicidas/farmacologia
16.
Molecules ; 24(11)2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31167374

RESUMO

Human African trypanosomiasis (HAT), also commonly known as sleeping sickness, is a neglected tropical disease affecting millions of people in poorly developed regions in sub-Saharan Africa. There is no satisfactory treatment for this infection. The investment necessary to bring new drugs to the market is a big deterrent to drug development, considering that the affected communities form a non-lucrative sector. However, natural products and many sesquiterpene lactones (STLs) in particular are very strong trypanocides. Research and applications of nano-drug delivery systems such as nanoparticles (NPs) have undergone unprecedented growth in the recent past. This is mainly due to the advantages offered by these systems, such as targeted delivery of the drug to the place of action (cell, parasite, etc), sustained release of the drug, increased bioavailability, reduced drug dosage, and reduction of undesired side effects, among others. In this study, the STLs α-santonin, arglabin, schkuhrin II, vernolepin, and eucannabinolide, all trypanocides, were loaded into polylactic acid (PLA) NPs through an emulsification-diffusion method. The NPs were stable, homogenous, and spherical in shape with a rounded knotty depression like a navel orange. The average particle sizes were 202.3, 220.3, 219.5, 216.9, and 226.4 nm for α-santonin, arglabin, schkuhrin II, vernolepin, and eucannabinolide, respectively. The NPs had encapsulation efficiencies of 94.6, 78.1, 76.8, 60.7, and 78.9% for α-santonin, arglabin, schkuhrin II, vernolepin, and eucannabinolide, respectively. The NPs loaded with arglabin, vernolepin, and eucannabinolide exhibited considerable antitrypanosomal activity against Trypanosoma brucei rhodesiense (Tbr) with free drug equivalent IC50 values of 3.67, 1.11 and 3.32 µM, respectively. None of the NP formulations displayed cytotoxicity towards mammalian cells (rat skeletal myoblast cell line L6). These results provide new insights into the possibility of incorporating STLs into nanoparticles, which may provide new options for their formulation in order to develop new drugs against HAT.


Assuntos
Lactonas/química , Nanopartículas/química , Poliésteres/química , Sesquiterpenos/química , Tripanossomicidas/química , Tripanossomicidas/farmacologia , Fenômenos Químicos , Composição de Medicamentos , Liberação Controlada de Fármacos , Humanos , Estrutura Molecular , Nanopartículas/ultraestrutura , Trypanosoma brucei rhodesiense/efeitos dos fármacos
17.
Eur J Med Chem ; 176: 162-174, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31103897

RESUMO

Chagas disease is a neglected protozoan disease that affects more than eight million people in developing countries. Due to the limited number and toxicity profiles of therapies in current use, new drugs are urgently needed. In previous studies, we reported the isolation of two related antitrypanosomal neolignans from Nectandra leucantha (Lauraceae). In this work, a semi-synthetic library of twenty-three neolignan derivatives was prepared to explore synthetically accessible structure activity relationships (SAR) against Trypanosoma cruzi. Five compounds demonstrated activity against trypomastigotes (IC50 values from 8 to 64 µM) and eight showed activity against intracellular amastigotes (IC50 values from 7 to 16 µM). Eighteen derivatives demonstrated no mammalian cytotoxicity up to 200 µM. The phenolic acetate derivative of natural dehydrodieugenol B was effective against both parasite forms and eliminated 100% of amastigotes inside macrophages. This compound caused rapid and intense depolarization of the mitochondrial membrane potential, with decreased levels of intracellular reactive oxygen species being observed. Fluorescence assays demonstrated that this derivative affected neither the permeability nor the electric potential of the parasitic plasma membrane, an effect also corroborated by scanning electron microscopy studies. Structure-activity relationship studies (SARs) demonstrated that the presence of at least one allyl side chain on the biaryl ether core was important for antitrypanosomal activity, and that the free phenol is not essential. This set of neolignan derivatives represents a promising starting point for future Chagas disease drug discovery studies.


Assuntos
Anisóis/farmacologia , Lignanas/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Anisóis/síntese química , Anisóis/química , Anisóis/toxicidade , Linhagem Celular , Membrana Celular/efeitos dos fármacos , Humanos , Lignanas/síntese química , Lignanas/química , Lignanas/toxicidade , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos Endogâmicos BALB C , Estrutura Molecular , Testes de Sensibilidade Parasitária , Espécies Reativas de Oxigênio/metabolismo , Relação Estrutura-Atividade , Tripanossomicidas/síntese química , Tripanossomicidas/química , Tripanossomicidas/toxicidade , Trypanosoma cruzi/crescimento & desenvolvimento , Trypanosoma cruzi/metabolismo
18.
Dalton Trans ; 48(22): 7644-7658, 2019 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-31049548

RESUMO

In the search for a more effective chemotherapy for the treatment of Chagas' disease and human African trypanosomiasis, caused by Trypanosoma cruzi and Trypanosoma brucei parasites, respectively, the use of organometallic compounds may be a promising strategy. In this work, eight new heterobimetallic compounds are described including four 5-nitrofuryl containing thiosemicarbazones as bioactive ligands (HL1-HL4) and dppf = 1,1'-bis(diphenylphosphino) ferrocene as an organometallic co-ligand. Complexes of the formula [MII(L)(dppf)](PF6) with M = Pd or Pt were synthesized and fully characterized in the solid state and in solution, including the determination of the molecular structure of four of them by single crystal X-ray diffraction methods. Most compounds showed activity in the low micromolar or submicromolar range against both parasites, with the platinum compounds being more active than the palladium analogues. Activity was significantly increased by generation of the M-dppf compounds (3-24 fold increase with respect to free ligands HL for T. cruzi and up to 99 fold increase with respect to HL for T. brucei). The inclusion of the organometallic co-ligand also led to lower toxicity in mammalian cells and higher selectivity towards both parasites when compared to the free HL compounds. The complexes interact with DNA and affect the redox metabolism of the parasites. Furthermore, the most active and selective compound of the new series showed no in vivo toxicity in zebrafish embryos.


Assuntos
Compostos Ferrosos/química , Metalocenos/química , Compostos Organometálicos/química , Compostos Organometálicos/farmacologia , Paládio/química , Platina/química , Tripanossomicidas/química , Tripanossomicidas/farmacologia , Células A549 , Animais , Bovinos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Ligantes , Compostos Organometálicos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Soroalbumina Bovina/metabolismo , Tripanossomicidas/metabolismo , Trypanosoma cruzi/efeitos dos fármacos
19.
Eur J Med Chem ; 174: 292-308, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31051403

RESUMO

Different compounds have been investigated as potent drugs for trypanosomiasis treatment, but no new drug has been marketed in the past 3 decades. 4-Thiazolidinone/thiazole as privileged structures and thiosemicarbazides cyclic analogs are well known scaffolds in novel antitrypanosomal agent design. We present here the design and synthesis of new hybrid molecules bearing thiazolidinone/thiazole cores linked by the hydrazone group with various molecular fragments. Structure optimization led to compounds with phenyl-indole or phenyl-imidazo[2,1-b][1,3,4]thiadiazole moieties showing excellent antitrypanosomal activity towards Trypanosoma brucei brucei and Trypanosoma brucei gambiense. Biological study allowed identifying compounds with the submicromolar levels of IC50, good selectivity indexes and relatively low cytotoxicity upon human primary fibroblasts as well as low acute toxicity.


Assuntos
Tiazolidinas/farmacologia , Tripanossomicidas/farmacologia , Animais , Linhagem Celular , Humanos , Concentração Inibidora 50 , Masculino , Camundongos , Estrutura Molecular , Relação Estrutura-Atividade , Tiazolidinas/síntese química , Tiazolidinas/química , Tiazolidinas/toxicidade , Tripanossomicidas/síntese química , Tripanossomicidas/química , Tripanossomicidas/toxicidade , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei gambiense/efeitos dos fármacos
20.
Pak J Pharm Sci ; 32(2 (Supplementary)): 825-829, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31103978

RESUMO

Trans-sialidase of Trypanosoma cruzi (TcTS) is a key enzyme in the infection process from parasite to host; therefore, it has been considered an important target for developing new anti-Chagas drugs. Different compounds with trypanocidal activity and/or inhibition of TcTS have been reported; however, some benzoic acid derivatives have shown high enzymatic inhibition but low trypanocidal activity and viceversa. These results show that each compound may possess a different mechanism of action. Based on the above, the compound 4-amino-3-nitrobenzoic acid (16), a potent TcTS inhibitor (77% inhibition in enzymatic assays) was selected to evaluate its effects on the expression level of the TS gene in T. cruzi epimastigotes and determine its involvement in the mechanism of action. Results showed an increase in the expression level of the TcTS gene, which confirmed that compound 16, has a direct effect on TcTS.


Assuntos
Glicoproteínas/genética , Neuraminidase/genética , Nitrobenzoatos/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Nitrobenzoatos/química , Reação em Cadeia da Polimerase em Tempo Real , Tripanossomicidas/química
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