RESUMO
Nifurtimox is a nitroheterocyclic drug employed for treatment of trypanosomiases (Chagas disease and West African sleeping sickness); its use for certain cancers has also been assessed. Despite having been in the market for over 50 years, knowledge of nifurtimox is still fragmentary and incomplete. Relevant aspects of the chemistry and biology of nifurtimox are reviewed to summarize the current knowledge of this drug. These comprise its chemical synthesis and the preparation of some analogues, as well as its chemical degradation. Selected physical data and physicochemical properties are also listed, along with different approaches toward the analytical characterization of the drug, including electrochemical (polarography, cyclic voltammetry), spectroscopic (ultraviolet-visible, nuclear magnetic resonance, electron spin resonance), and single crystal X-ray diffractometry. The array of polarographic, ultraviolet-visible spectroscopic, and chromatographic methods available for the analytical determination of nifurtimox (in bulk drug, pharmaceutical formulations, and biological samples), are also presented and discussed, along with chiral chromatographic and electrophoretic alternatives for the separation of the enantiomers of the drug. Aspects of the drug likeliness of nifurtimox, its classification in the Biopharmaceutical Classification System, and available pharmaceutical formulations are detailed, whereas pharmacological, chemical, and biological aspects of its metabolism and disposition are discussed.
Assuntos
Doença de Chagas , Farmácia , Humanos , Nifurtimox/química , Nifurtimox/farmacologia , Nifurtimox/uso terapêutico , Doença de Chagas/tratamento farmacológico , Preparações FarmacêuticasRESUMO
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/químicaRESUMO
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 fármacosRESUMO
OBJECTIVE: This work aims to collect publications of available drugs for reposition and new substance development against the Chagas disease, since they represent the beginning of a path for new discoveries of viable alternatives to improve the prognosis of millions of patients around the world. PATIENTS AND METHODS: An extended research on English and Portuguese-language literature in the Scientific Electronic Library Online - Scielo, SciFinder and PubMed - database was made. The bibliography was screened using the keywords "Chagas Disease" and "Treatment". RESULTS: Despite the low resources available for research and development of drugs against Chagas disease, the knowledge produced in this area is large but not directly proportional to the therapeutic advances. Two categories were analyzed, such as drug repositioning, and new substances were researched. CONCLUSIONS: Even if great findings were reported, more efforts are necessary to find new therapies against Trypanosoma cruzi (T. cruzi).
Assuntos
Doença de Chagas/tratamento farmacológico , Tripanossomicidas/uso terapêutico , Doença de Chagas/diagnóstico , Reposicionamento de Medicamentos , Humanos , Estrutura Molecular , Nifurtimox/química , Nifurtimox/farmacologia , Nifurtimox/uso terapêutico , Nitroimidazóis/química , Nitroimidazóis/farmacologia , Nitroimidazóis/uso terapêutico , Prognóstico , Tripanossomicidas/química , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacosRESUMO
Chagas disease has spread throughout the world mainly because of the migration of infected individuals. In Brazil, only benznidazole (Bnz) is used; however, it is toxic and not active in the chronic phase, and cases of resistance are described. This work aimed at the synthesis and the trypanocidal evaluation in vitro and in vivo of six new Bnz analogues (3-8). They were designed by exploring the bioisosteric substitution between the amide group contained in Bnz and the 1,2,3-triazole ring. All the compounds were synthesized in good yields. With the exception of compound 7, the in vitro biological evaluation shows that all Bnz analogues were active against the amastigote form, whereas only compounds 3, 4, 5, and 8 were active against trypomastigote. Compounds 4 and 5 showed the most promising activities in vitro against the form of trypomastigote, being more active than Bnz. In vivo evaluation of compounds, 3-8 showed lower potency and higher toxicity than Bnz. Although the 1,2,3-triazole ring has been described in the literature as an amide bioisostere, its substitution here has reduced the activity of the compounds and made them more toxic. Thus, further molecular optimization could provide novel therapeutic agents for Chagas' disease.
Assuntos
Doença de Chagas/tratamento farmacológico , Nitroimidazóis/química , Triazóis/química , Tripanossomicidas/química , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Doença de Chagas/veterinária , Masculino , Camundongos , Nifurtimox/química , Nifurtimox/farmacologia , Nifurtimox/uso terapêutico , Nitroimidazóis/farmacologia , Nitroimidazóis/uso terapêutico , Tripanossomicidas/farmacologia , Tripanossomicidas/uso terapêutico , Trypanosoma cruzi/efeitos dos fármacosRESUMO
Chagas disease is caused by the parasite Trypanosoma cruzi and is regularly found among particular people living in Central and South America. Paediatric Chagas disease occurs in 1-10% of infants of infected mothers. The major important point considered in the treatment of congenital Chagas disease focuses on killing the parasite in acute infection and managing signs and symptoms in later stages. Nowadays, two drugs benznidazole and nifurtimox are currently available in the market for the treatment of paediatric Chagas disease.
Assuntos
Antiparasitários/farmacologia , Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Descoberta de Drogas , Nifurtimox/farmacologia , Nitroimidazóis/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Antiparasitários/síntese química , Antiparasitários/química , Humanos , Nifurtimox/síntese química , Nifurtimox/química , Nitroimidazóis/síntese química , Nitroimidazóis/química , Testes de Sensibilidade ParasitáriaRESUMO
American Trypanosomiasis or Chagas disease is a prevalent, neglected and serious debilitating illness caused by the kinetoplastid protozoan parasite Trypanosoma cruzi. The current chemotherapy is limited only to nifurtimox and benznidazole, two drugs that have poor efficacy in the chronic phase and are rather toxic. In this scenario, more efficacious and safer drugs, preferentially acting through a different mechanism of action and directed against novel targets, are particularly welcome. Cruzipain, the main papain-like cysteine peptidase of T. cruzi, is an important virulence factor and a chemotherapeutic target with excellent pre-clinical validation evidence. Here, we present the identification of new Cruzipain inhibitory scaffolds within the GlaxoSmithKline HAT (Human African Trypanosomiasis) and Chagas chemical boxes, two collections grouping 404 non-cytotoxic compounds with high antiparasitic potency, drug-likeness, structural diversity and scientific novelty. We have adapted a continuous enzymatic assay to a medium-throughput format and carried out a primary screening of both collections, followed by construction and analysis of dose-response curves of the most promising hits. Using the identified compounds as a starting point a substructure directed search against CHEMBL Database revealed plausible common scaffolds while docking experiments predicted binding poses and specific interactions between Cruzipain and the novel inhibitors.
Assuntos
Antiprotozoários/farmacologia , Ensaios de Triagem em Larga Escala/métodos , Kinetoplastida/efeitos dos fármacos , Proteínas de Protozoários/antagonistas & inibidores , Antiprotozoários/química , Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Cisteína Endopeptidases/química , Cisteína Endopeptidases/metabolismo , Interações Hospedeiro-Parasita/efeitos dos fármacos , Humanos , Kinetoplastida/enzimologia , Kinetoplastida/fisiologia , Simulação de Acoplamento Molecular , Estrutura Molecular , Nifurtimox/química , Nifurtimox/farmacologia , Nitroimidazóis/química , Nitroimidazóis/farmacologia , Domínios Proteicos , Proteínas de Protozoários/química , Proteínas de Protozoários/metabolismo , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/enzimologia , Trypanosoma cruzi/fisiologiaRESUMO
BACKGROUND & OBJECTIVE: Chagas disease or American trypanosomiasis is a major parasitic disease in Latin America with restricted available treatment: nifurtimox and benznidazole. These two drugs are ineffective in the chronic phase of the disease; therefore, there is a need for the development of new, efficient and safe drugs for the treatment of this pathology. With this goal, one of the promising targets is trypanothione reductase (TR), a key enzyme in the metabolism of Trypanosoma cruzi. CONCLUSION: In this review, we analyse the importance of TR as a drug target, as well as the well-known and new inhibitors reported in the last decade as potential therapeutic agents for Chagas disease.
Assuntos
Doença de Chagas/tratamento farmacológico , Sistemas de Liberação de Medicamentos , NADH NADPH Oxirredutases/metabolismo , Tripanossomicidas/química , Tripanossomicidas/uso terapêutico , Trypanosoma cruzi/enzimologia , Animais , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Humanos , Estrutura Molecular , Nifurtimox/química , Nifurtimox/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacosRESUMO
For years, Chagas disease treatment has been limited to only two drugs of highly questionable and controversial use (Nifurtimox(®) and Benznidazole(®)). In the search of effective drugs, many efforts have been made, but only a few structures have emerged as actual candidates. Heading into this, the multitarget-directed approach appears as the best choice. In this framework, indazoles were shown to be potent Trypanosoma cruzi growth inhibitors, being able to lead both the formation of reactive oxygen species and the inhibition of trypanothione reductase. Herein, we discuss the main structural factors that rule the anti-T. cruzi properties of indazoles, and how they would be involved in the biological properties as well as in the action mechanisms, attempting to make parallels between the old paradigms and current evidences in order to outline what could be the next steps to follow in regard to the future drug design for Chagas disease treatment.
Assuntos
Indazóis/química , Tripanossomicidas/química , Trypanosoma cruzi/metabolismo , Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Desenho de Fármacos , Humanos , Indazóis/farmacologia , Indazóis/uso terapêutico , NADH NADPH Oxirredutases/antagonistas & inibidores , NADH NADPH Oxirredutases/metabolismo , Nifurtimox/química , Nifurtimox/farmacologia , Nifurtimox/uso terapêutico , Nitroimidazóis/química , Nitroimidazóis/farmacologia , Nitroimidazóis/uso terapêutico , Proteínas de Protozoários/antagonistas & inibidores , Proteínas de Protozoários/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Tripanossomicidas/farmacologia , Tripanossomicidas/uso terapêutico , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/enzimologiaRESUMO
EVALUATION OF: Hall BS, Bot C, Wilkinson SR. Nifurtimox activation by trypanosomal type I nitroreductases generates cytotoxic nitrile metabolites. J. Biol. Chem. 286, 13088-13095 (2011). The prodrug nifurtimox has been one of the pharmacologic alternatives to treat Chagas disease and currently forms part of a combinational therapy to treat West African trypanosomiasis. Despite this, nifurtimox's mechanism of action is only partially understood and has been related to induction of oxidative stress in the target cell. An alternative mechanism involving reductive activation by a eukaryotic type I nitroreductase has been described. Bloodstream form Trypanosoma brucei overexpressing enzymes, proposed to metabolize nifurtimox, were generated and only cells with elevated levels of the nitroreductase displayed altered susceptibility to the drug, implying that it has a key role in drug action. Reduction of nifurtimox by trypanosomal type I nitroreductases was shown to be insensitive to oxygen and yielded a product characterized by liquid chromatography/mass spectrometry as an unsaturated open chain nitrile. This nitrile inhibited both parasite and mammalian cell growth at equivalent concentrations, in marked contrast to the parental prodrug. These studies indicated that nifurtimox selectivity against T. brucei could be the result of the expression of a parasite-encoded type I nitroreductase.
Assuntos
Antiprotozoários/farmacologia , Nifurtimox/farmacologia , Pró-Fármacos/farmacologia , Antiprotozoários/química , Humanos , Leishmania/efeitos dos fármacos , Modelos Moleculares , Estrutura Molecular , Nifurtimox/química , Pró-Fármacos/química , Trypanosoma brucei brucei/efeitos dos fármacosRESUMO
Chagas disease is caused by the trypanosomatid parasite Trypanosoma cruzi and threatens millions of lives in South America. As other neglected diseases there is almost no research and development effort by the pharmaceutical industry and the treatment relies on two drugs, Nifurtimox and Benznidazole, discovered empirically more than three decades ago. Nifurtimox, a nitrofurane derivative, is believed to exert its biological activity through the bioreduction of the nitro-group to a nitro-anion radical which undergoes redox-cycling with molecular oxygen. This hypothesis is generally accepted, although arguments against it have been presented. In the present work we studied the ability of Nifurtimox and five N-oxide-containing heterocycles to induce oxidative stress in T. cruzi. N-Oxide-containing heterocycles represent a promising group of new trypanosomicidal agents and their mode of action is not completely elucidated. The results here obtained argue against the oxidative stress hypothesis almost for all the studied compounds, including Nifurtimox. A significant reduction in the level of parasitic low-molecular-weight thiols was observed after Nifurtimox treatment; however, it was not linked to the production of reactive oxidant species. Besides, redox-cycling is only observed at high Nifurtimox concentrations (>400microM), two orders of magnitude higher than the concentration required for anti-proliferative activity (5microM). Our results indicate that an increase in oxidative stress is not the main mechanism of action of Nifurtimox. Among the studied N-oxide-containing heterocycles, benzofuroxan derivatives strongly inhibited parasite dehydrogenase activity and affected mitochondrial membrane potential. The indazole derivative raised intracellular oxidants production, but it was the least effective as anti-T. cruzi.
Assuntos
Óxidos N-Cíclicos/farmacologia , Nifurtimox/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Benzoxazóis/farmacologia , Células Cultivadas , Óxidos N-Cíclicos/química , Potenciais da Membrana/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Estrutura Molecular , Nifurtimox/química , Oxirredução/efeitos dos fármacos , Oxirredutases/efeitos dos fármacos , Oxirredutases/metabolismo , Oxigênio/metabolismo , Tripanossomicidas/química , Trypanosoma cruzi/crescimento & desenvolvimento , Trypanosoma cruzi/metabolismoRESUMO
Ten 5-nitro-2-furyl derivatives, with good to excellent in vitro anti-Trypanosoma cruzi activity, and nifurtimox were tested oral and intraperitoneally on healthy animals for its acute toxicity on murine models. According to animals' survival percentage, organ histological results, biochemical and haematological findings, three new derivatives, with toxicity like nifurtimox, were selected to test in vivo as antichagasic agents. Clearly, dependences between chemical structure and both acute toxicity and in vivo anti-T. cruzi activity were observed. 4-Hexyl-1-[3-(5-nitro-2-furyl)-2-propenylidene]semicarbazide displayed good profile as anti-T. cruzi agent and better acute toxicity profile than nifurtimox.
Assuntos
Doença de Chagas/tratamento farmacológico , Nifurtimox/química , Nifurtimox/uso terapêutico , Nitrofuranos/química , Nitrofuranos/uso terapêutico , Tripanossomicidas/química , Tripanossomicidas/uso terapêutico , Animais , Doença de Chagas/patologia , Feminino , Camundongos , Nifurtimox/toxicidade , Nitrofuranos/toxicidade , Relação Estrutura-Atividade , Tripanossomicidas/toxicidade , Trypanosoma cruzi/efeitos dos fármacosRESUMO
Electron spin resonance (ESR) spectra of radicals obtained from two analogues of the antiprotozoal drug nifurtimox by electrolytic and Trypanosoma cruzi reduction were analyzed. The electrochemistry of these compounds was studied using cyclic voltammetry. STO 3-21G ab initio and INDO molecular orbital calculations were performed to obtain the optimized geometries and spin distribution, respectively. The antioxidant effect of glutathione on the nitroheterocycle radical was evaluated. DMPO spin trapping was used to investigate the possible formation of free radicals in the trypanosome microsomal system. Nitro1 and Nitro2 nitrofuran analogues showed better antiparasitic activity than nifurtimox. Nitro2 produced oxygen redox cycling in T. cruzi epimastigotes. The ESR signal intensities were consistent with the trapping of either the hydroxyl radical or the Nitro2 analogue radicals. These results are in agreement with the biological observation that Nitro2 showed anti-Chagas activity by an oxidative stress mechanism.
Assuntos
Antiprotozoários/química , Nifurtimox/química , Nitrofuranos/química , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/fisiologia , Animais , Antiprotozoários/farmacologia , Eletroquímica , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres/análise , Nifurtimox/farmacologia , Nitrofuranos/farmacologia , Detecção de SpinRESUMO
In a search for antichagasic drugs, 14 new 4-(nitroarylidene)-1,2,6-thiadiazin-3,5-dione 1,1-dioxide derivatives were synthesized and tested in vitro against the epimastigote form of Trypanosoma cruzi and some of them showed important antiprotozoan activity. Attempts to synthesize new 4-(nitroarylidene)-3,5-diamino-1,2,6-thiadiazine 1,1-dioxides were unsuccessful. The antichagasic properties of nitroarylidene-malononitrile and nitroarylidene-cyanoacetamide derivatives, thus obtained, were also tested. The cytotoxic properties against Vero cells of compounds which showed remarkable in vitro antichagasic activity were evaluated. All compounds tested exhibited high toxicity percentages at 100 micrograms/ml. However, compound 3c showed in vitro antichagasic and cytotoxic properties such as nifurtimox at the dose of 10 micrograms/ml.
Assuntos
Tiadiazinas/síntese química , Tripanossomicidas/síntese química , Animais , Chlorocebus aethiops , Humanos , Espectroscopia de Ressonância Magnética , Nifurtimox/química , Nifurtimox/farmacologia , Nifurtimox/toxicidade , Nitroimidazóis/química , Nitroimidazóis/farmacologia , Nitroimidazóis/toxicidade , Espectrofotometria Infravermelho , Tiadiazinas/farmacologia , Tiadiazinas/toxicidade , Tripanossomicidas/farmacologia , Tripanossomicidas/toxicidade , Trypanosoma cruzi/efeitos dos fármacos , Células VeroRESUMO
Electrochemical studies (Formal Potentials and Coulometry) were performed on several analogues of Nifurtimox, in order to gain insight on the proposed mechanism of action of these drugs. It is thought that Nifurtimox shows part of its trypanocidal activity via an electron transfer process, leading to the production of active oxygen species that kill the parasite. Formal potentials provide relevant data about the feasibility of electron transfer in vivo. All analogues tested contained the nitro group, which is the most easily reducible group in the parent drug Nifurtimox. The formal potentials values determined ranged from -1.86 to -0.46 V. Coulometric runs were carried out to study the one-electron transfer process. A good correlation between formal potentials and biological activity was found.
Assuntos
Nifurtimox/farmacologia , Animais , Fenômenos Químicos , Físico-Química , Eletroquímica , Transporte de Elétrons , Nifurtimox/química , Relação Estrutura-Atividade , Trypanosoma cruzi/efeitos dos fármacosRESUMO
Substitution of nifurtimox tetrahydrothiazine moiety by triazol-4-yl, benzimidazol-l-yl, pyrazol-l-yl or related aromatic nitrogen heterocycles determines changes in the quantum chemistry descriptors of the molecule, namely, (a) greater negative LUMO energy; (b) lesser electron density on specific atoms, especially on the nitro group atoms, and (c) modification of individual net atomic charges at relevant atoms. These variations correlate with the greater capability of nifurtimox analogues for redox-cycling and oxygen radical production, after one-electron reduction by ascorbate or reduced flavoenzymes. Variation of the nitrofurans electronic structure can also explain the greater activity of nifurtimox analogues as inhibitors of glutathione reductase and Trypanosoma cruzi growth, although other factors, such as molecular hydrophobicity and connectivity may contribute to the latter inhibition.