RESUMO
BACKGROUND: Near to 5-7 million people are infected with T. cruzi in the world, and about 10,000 people per year die of problems associated with this disease. METHODS: Herein, the synthesis, antitrypanosomal and antimycobacterial activities of seventeen coumarinic N-acylhydrazonic derivatives have been reported. RESULTS: These compounds were synthesized using methodology with reactions global yields ranging from 46%-70%. T. cruzi in vitro effects were evaluated against trypomastigote and amastigote, forming M. tuberculosis activity towards H37Rv sensitive strain and resistant strains. DISCUSSION: Against T. cruzi, the more active compounds revealed only moderate activity IC50/96h~20 µM for both trypomastigotes and amastigotes intracellular forms. (E)-2-oxo-N'- (3,4,5-trimethoxybenzylidene)-2H-chromene-3-carbohydrazide showed meaningful activity in INH resistant/RIP resistant strain. CONCLUSION: These compound acting as multitarget could be good leads for the development of new trypanocidal and bactericidal agents.
Assuntos
Cumarínicos/química , Hidrazonas/síntese química , Hidrazonas/farmacologia , Nitrogênio/química , Trypanosoma/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Antiprotozoários/síntese química , Antiprotozoários/química , Antiprotozoários/farmacologia , Técnicas de Química Sintética , Farmacorresistência Bacteriana/efeitos dos fármacos , Hidrazonas/química , Mycobacterium tuberculosis/efeitos dos fármacosRESUMO
Chagas disease is a neglected illness endemic in Latin America that mainly affects rural populations. The etiological agent of Chagas disease is the protozoan Trypanosoma cruzi, which has three different parasite stages and a dixenous life cycle that includes colonization of the vertebrate and invertebrate hosts. During its life cycle, T. cruzi is subjected to stress conditions, including variations in nutrient availability and pH, which impact parasite survival and differentiation. The plasticity of mitochondrial function in trypanosomatids has been defined as mitochondrial activity related to substrate availability. Thus, mitochondrial remodeling and autophagy, which is a constitutive cellular process of turnover and recycling of cellular components, may constitute a response to the nutritional and pH stress in the host. To assess these processes, epimastigotes were subjected to acidic, alkaline, and nutritional stress conditions, and mitochondrial function and its influence on the autophagic process were evaluated. Our data demonstrated that the three stress conditions affected the mitochondrial structure, inducing organelle swelling and impaired oxidative phosphorylation. Stressed epimastigotes produced increased ROS levels and overexpressed antioxidant enzymes. The stress conditions resulted in an increase in the number of autophagosomes and exacerbated the expression of different autophagy-related genes (Atgs). A correlation between mitochondrial dysfunction and autophagic phenotypes was also observed. After 24 h, acid stress and nutritional deprivation induced metacyclogenesis phenotypes (mitochondrial remodeling and autophagy). On the other hand, alkaline stress was transient due to insect blood feeding and culminated in an increase in autophagic flux as a survival mechanism.
Assuntos
Mitocôndrias/patologia , Estresse Fisiológico , Trypanosoma cruzi/fisiologia , Animais , Autofagossomos/metabolismo , Autofagia/fisiologia , Doença de Chagas/parasitologia , Humanos , Concentração de Íons de Hidrogênio , Estágios do Ciclo de Vida/fisiologia , Microscopia Eletrônica de Transmissão , Mitocôndrias/ultraestrutura , Espécies Reativas de Oxigênio/metabolismo , Trypanosoma cruzi/citologiaRESUMO
BACKGROUND: Chagas disease, which is caused by the protozoan Trypanosoma cruzi, is endemic to Latin America and mainly affects low-income populations. Chemotherapy is based on two nitrocompounds, but their reduced efficacy encourages the continuous search for alternative drugs. Our group has characterised the trypanocidal effect of naphthoquinones and their derivatives, with naphthoimidazoles derived from ß-lapachone (N1, N2 and N3) being the most active in vitro. OBJECTIVES: In the present work, the effects of N1, N2 and N3 on acutely infected mice were investigated. METHODS: in vivo activity of the compounds was assessed by parasitological, biochemical, histopathological, immunophenotypical, electrocardiographic (ECG) and behavioral analyses. FINDINGS: Naphthoimidazoles led to a decrease in parasitaemia (8 dpi) by reducing the number of bloodstream trypomastigotes by 25-50% but not by reducing mortality. N1 protected mice from heart injury (15 dpi) by decreasing inflammation. Bradycardia was also partially reversed after treatment with N1 and N2. Furthermore, the three compounds did not reverse hepatic and renal lesions or promote the improvement of other evaluated parameters. MAIN CONCLUSION: N1 showed moderate trypanocidal and promising immunomodulatory activities, and its use in combination with benznidazole and/or anti-arrhythmic drugs as well as the efficacy of its alternative formulations must be investigated in the near future.
Assuntos
Doença de Chagas/tratamento farmacológico , Naftoquinonas/uso terapêutico , Nitroimidazóis/uso terapêutico , Tripanossomicidas/uso terapêutico , Doença Aguda , Animais , Anti-Inflamatórios , Modelos Animais de Doenças , Eletrocardiografia , Masculino , Camundongos , Naftoquinonas/química , Nitroimidazóis/química , Parasitemia/tratamento farmacológico , Fatores de Tempo , Tripanossomicidas/químicaRESUMO
Ortho-Quinones represent a special class of redox active compounds associated with a spectrum of pronounced biological activities, including selective cytotoxicity and antimicrobial actions. The modification of the quinone ring by simple nitrogen and sulphur substitutions leads to several new classes of compounds with their own, distinct redox behaviour and equally distinct activities against cancer cell lines and Trypanosoma cruzi. Some of the compounds investigated show activity against T. cruzi at concentrations of 24.3 and 65.6 µM with a selectivity index of around 1. These results demonstrate that simple chemical modifications on the ortho-quinone ring system, in particular, by heteroatoms such as nitrogen and sulphur, transform these simple redox molecules into powerful cytotoxic agents with considerable "potential", not only in synthesis and electrochemistry, but also, in a broader sense, in health sciences.
RESUMO
BACKGROUND: Approximately, 5-7 million people are infected with T. cruzi in the world, and approximately 10,000 people per year die of complications linked to this disease. METHODS: This work describes the construction of a new family of hidrazonoyl substituted derivatives, structurally designed exploring the molecular hybridization between megazol and nitrofurazone. RESULTS AND DISCUSSION: The compounds were evaluated for their in vitro activity against bloodstream trypomastigotes of Trypanosoma cruzi, etiological agent of Chagas disease, and for their potential toxicity to mammalian cells. CONCLUSION: Among these hydrazonoyl derivatives, we identified the derivative (4) that showed trypanocidal activity (IC50/24 h = 15.0 µM) similar to Bz, the standard drug, and low toxicity to mammalian cells, reaching an SI value of 18.7.
Assuntos
Hidrazonas/síntese química , Hidrazonas/farmacologia , Tripanossomicidas/síntese química , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Linhagem Celular , Técnicas de Química Sintética , Hidrazonas/química , Relação Estrutura-Atividade , Tripanossomicidas/químicaRESUMO
BACKGROUND: Although several research efforts have been made worldwide to discover novel drug candidates for the treatment of Chagas disease, the nitroimidazole drug benznidazol remains the only therapeutic alternative in the control of this disease. However, this drug presents reduced efficacy in the chronic form of the disease and limited safety after long periods of administration, making it necessary to search for new, more potent and safe prototypes. OBJECTIVE: We described herein the synthesis and the trypanocidalaction of new functionalized carbohydrazonamides (2-10) against trypomastigote forms of Trypanosoma cruzi. METHODS: These compounds were designed through the application of molecular hybridization concept between two potent anti-T. cruzi prototypes, the nitroimidazole derivative megazol (1) and the cinnamyl N-acylhydrazone derivative (14) which have been shown to be twice as potent in vitro as benznidazole. RESULTS: The most active compounds were the (Z)-N'-((E)-3-(4-nitrophenyl)-acryloyl)-1-methyl-5- nitro-1H-imidazol-2-carbohydrazonamide (6) (IC50=9.50 µM) and the (Z)-N'-((E)-3-(4- hydroxyphe-nyl)-acryloyl)-1-methyl-5-nitro-1H-imidazol-2-carbohydrazonamide (8) (IC50=12.85 µM), which were almost equipotent to benznidazole (IC50=10.26 µM) used as standard drug. The removal of the amine group attached to the imine subunit in the corresponding N-acylhydrazone derivatives (11-13) resulted in less potent or inactive compounds. The para-hydroxyphenyl derivative (8) presented also a good selectivity index (SI = 32.94) when tested against mammalian cells from Swiss mice. CONCLUSION: The promising trypanocidal profile of new carbohydrazonamide derivatives (6) and (8) was characterized. These compounds have proved to be a good starting point for the design of more effective trypanocidal drug candidates.
Assuntos
Doença de Chagas/tratamento farmacológico , Tripanossomicidas/síntese química , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Células Cultivadas , Desenho de Fármacos , Macrófagos Peritoneais/efeitos dos fármacos , Camundongos , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade , Tripanossomicidas/químicaRESUMO
Naphthoquinones are of key importance in organic synthesis and medicinal chemistry. In the last few years, various synthetic routes have been developed to prepare bioactive compounds derived or based on lapachones. In this sense, this review is mainly focused on the synthetic aspects and strategies used for the design of these compounds on the basis of their biological activities for the development of drugs against the neglected diseases leishmaniases and Chagas disease and also cancer. Three strategies used to develop bioactive quinones are discussed and categorized: (i) C-ring modification, (ii) redox centre modification and (iii) A-ring modification. Framed within these strategies for the development of naphthoquinoidal compounds against T. cruzi. Leishmania and cancer, reactions including copper-catalyzed azide-alkyne cycloaddition (click chemistry), palladium-catalysed cross couplings, C-H activation reactions, Ullmann couplings and heterocyclisations reported up to July 2019 will be discussed. The aim of derivatisation is the generation of novel molecules that can potentially inhibit cellular organelles/processes, generate reactive oxygen species and increase lipophilicity to enhance penetration through the plasma membrane. Modified lapachones have emerged as promising prototypes for the development of drugs against leishmaniases, Chagas disease and cancer.
Assuntos
Antineoplásicos/farmacologia , Antiprotozoários/farmacologia , Doença de Chagas/tratamento farmacológico , Doenças Negligenciadas/tratamento farmacológico , Neoplasias/tratamento farmacológico , Quinonas/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Antiprotozoários/síntese química , Antiprotozoários/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Leishmania/efeitos dos fármacos , Neoplasias/patologia , Quinonas/síntese química , Quinonas/química , Trypanosoma cruzi/efeitos dos fármacosRESUMO
Thirty four halogen and selenium-containing quinones, synthesized by rhodium-catalyzed C-H bond activation and palladium-catalyzed cross-coupling reactions, were evaluated against bloodstream trypomastigotes of T. cruzi. We have identified fifteen compounds with IC50/24 h values of less than 2 µM. Electrochemical studies on A-ring functionalized naphthoquinones were also performed aiming to correlate redox properties with trypanocidal activity. For instance, (E)-5-styryl-1,4-naphthoquinone 59 and 5,8-diiodo-1,4-naphthoquinone 3, which are around fifty fold more active than the standard drug benznidazole, are potential derivatives for further investigation. These compounds represent powerful new agents useful in Chagas disease therapy.
Assuntos
Técnicas Eletroquímicas , Quinonas/farmacologia , Ródio/química , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Catálise , Relação Dose-Resposta a Droga , Macrófagos/efeitos dos fármacos , Camundongos , Estrutura Molecular , Quinonas/síntese química , Quinonas/química , Relação Estrutura-Atividade , Tripanossomicidas/síntese química , Tripanossomicidas/químicaRESUMO
The QSAR study of 34 2-aryl-naphthoimidazoles screened so far revealed that σi is the most important factor for their lytic activity on the bloodstream trypomastigote forms of T. cruzi, the etiologic agent of Chagas disease. Based on this result, 16 new N-alkyl-naphthoimidazoles derived from 6,6-dimethyl-3,4,5,6-tetrahydrobenzo[7,8]chromene[5,6-d]imidazole (the product of the reaction of ß-lapachone with paraformaldehyde) by its reaction with halo-alkanes were prepared and evaluated against the parasite and peritoneal macrophages. The N1-n-hexyl and N3-n-hexyl naphthoimidazoles were 2.2 and 3.2 times more active than the standard drug benznidazole with selectivity indices of 2.7 and 13.4, respectively.
RESUMO
We report herein a straightforward and efficient one-step reaction to prepare new nor-ß-lapachone derivatives tethered with phenylthio groups at position 3 of the furan ring. We have screened the compounds on bloodstream trypomastigotes of Trypanosoma cruzi, the causative agent of Chagas disease, aimed at finding a new prototype with high trypanocidal activity. The new compounds possess a broad range of activity (IC50/24h from 9.2 to 182.7 µM), higher than the original quinone (391.5 µM) and four of them higher than standard drug benznidazole (103.6 µM). The most active was compound 13b (9.2 µM), being 11 times active than benznidazole and the less toxic derivative to heart muscle cells.
Assuntos
Benzofuranos/química , Naftoquinonas/química , Tripanossomicidas/síntese química , Animais , Benzofuranos/uso terapêutico , Benzofuranos/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Doença de Chagas/tratamento farmacológico , Embrião de Mamíferos/citologia , Coração/efeitos dos fármacos , Humanos , Camundongos , Miocárdio/citologia , Miocárdio/metabolismo , Naftoquinonas/uso terapêutico , Naftoquinonas/toxicidade , Relação Estrutura-Atividade , Tripanossomicidas/uso terapêutico , Tripanossomicidas/toxicidade , Trypanosoma cruzi/efeitos dos fármacosRESUMO
Nitroimidazoles exhibit high microbicidal activity, but mutagenic, genotoxic and cytotoxic properties have been attributed to the presence of the nitro group. However, we synthesised nitroimidazoles with activity against the trypomastigotes of Trypanosoma cruzi, but that were not genotoxic. Herein, nitroimidazoles (11-19) bearing different substituent groups were investigated for their potential induction of genotoxicity (comet assay) and mutagenicity (Salmonella/Microsome assay) and the correlations of these effects with their trypanocidal effect and with megazol were investigated. The compounds were designed to analyse the role played by the position of the nitro group in the imidazole nucleus (C-4 or C-5) and the presence of oxidisable groups at N-1 as an anion receptor group and the role of a methyl group at C-2. Nitroimidazoles bearing NO2 at C-4 and CH3 at C-2 were not genotoxic compared to those bearing NO 2 at C-5. However, when there was a CH3 at C-2, the position of the NO2 group had no influence on the genotoxic activity. Fluorinated compounds exhibited higher genotoxicity regardless of the presence of CH3 at C-2 or NO2 at C-4 or C-5. However, in compounds 11 (2-CH3; 4-NO2; N-CH2OHCH2Cl) and 12 (2-CH3; 4-NO2; N-CH2OHCH2F), the fluorine atom had no influence on genotoxicity. This study contributes to the future search for new and safer prototypes and provide.
Assuntos
Animais , Camundongos , Dano ao DNA/efeitos dos fármacos , Nitroimidazóis/química , Nitroimidazóis/toxicidade , Salmonella/efeitos dos fármacos , Trypanosoma cruzi/efeitos dos fármacos , Ensaio Cometa , Relação Dose-Resposta a Droga , Testes de Mutagenicidade , Relação Estrutura-AtividadeRESUMO
Nitroimidazoles exhibit high microbicidal activity, but mutagenic, genotoxic and cytotoxic properties have been attributed to the presence of the nitro group. However, we synthesised nitroimidazoles with activity against the trypomastigotes of Trypanosoma cruzi, but that were not genotoxic. Herein, nitroimidazoles (11-19) bearing different substituent groups were investigated for their potential induction of genotoxicity (comet assay) and mutagenicity (Salmonella/Microsome assay) and the correlations of these effects with their trypanocidal effect and with megazol were investigated. The compounds were designed to analyse the role played by the position of the nitro group in the imidazole nucleus (C-4 or C-5) and the presence of oxidisable groups at N-1 as an anion receptor group and the role of a methyl group at C-2. Nitroimidazoles bearing NO2 at C-4 and CH3 at C-2 were not genotoxic compared to those bearing NO 2 at C-5. However, when there was a CH3 at C-2, the position of the NO2 group had no influence on the genotoxic activity. Fluorinated compounds exhibited higher genotoxicity regardless of the presence of CH3 at C-2 or NO2 at C-4 or C-5. However, in compounds 11 (2-CH3; 4-NO2; N-CH2OHCH2Cl) and 12 (2-CH3; 4-NO2; N-CH2OHCH2F), the fluorine atom had no influence on genotoxicity. This study contributes to the future search for new and safer prototypes and provide.
Assuntos
Dano ao DNA/efeitos dos fármacos , Nitroimidazóis/química , Nitroimidazóis/toxicidade , Salmonella/efeitos dos fármacos , Trypanosoma cruzi/efeitos dos fármacos , Animais , Ensaio Cometa , Relação Dose-Resposta a Droga , Camundongos , Testes de Mutagenicidade , Relação Estrutura-AtividadeRESUMO
The available treatment for the prevention and cure of Chagas disease, caused by the protozoan Trypanosoma cruzi, is still unsatisfactory. Thus, there is an urgent need to develop new drugs. In the last few years, our research group has focused on finding a new chemical entity able to target the infectious bloodstream trypomastigotes. In this study, we assayed 16 ß-lapachone analogous with modifications in the pyran and aromatic ring to find a new prototype with high trypanocidal activity. Interestingly, two ortho-naphthoquinones presented the best trypanocidal profile (8c and 8d with an IC50/24 h of 26.9 ± 1.3 and 23.5 ± 2.5 µM, respectively), which were 4 to 17 times more effective than ß-lapachone (391.5 ± 16.5 µM) and the standard drug benznidazole (103.6 ± 0.6 µM). The introduction of a hydroxyl group on the compounds' aromatic ring modulated their biological profile by increasing their activity not only for cancer cells (MDAMB435), as previously described in literature, but also against T. cruzi. The Structure-Activity Relationship (SAR) study indicated that this introduction modulated HOMO and MEP parameters, improving the trypanocidal activity.
Assuntos
Naftoquinonas/química , Piranos/química , Tripanossomicidas/química , Trypanosoma cruzi/efeitos dos fármacos , Animais , Doença de Chagas/sangue , Doença de Chagas/tratamento farmacológico , Modelos Animais de Doenças , Concentração Inibidora 50 , Camundongos , Modelos Biológicos , Modelos Moleculares , Estrutura Molecular , Naftoquinonas/farmacologia , Testes de Sensibilidade Parasitária , Piranos/farmacologia , Relação Estrutura-Atividade , Tripanossomicidas/farmacologia , Trypanosoma cruzi/crescimento & desenvolvimento , Trypanosoma cruzi/patogenicidadeRESUMO
In our continued search for novel trypanocidal compounds, twenty-six derivatives of para- and ortho-naphthoquinones coupled to 1,2,3-triazoles were synthesized. These compounds were evaluated against the infective bloodstream form of Trypanosoma cruzi, the etiological agent of Chagas disease. Compounds 17-24, 28-30 and 36-38 are described herein for the first time. Three of these novel compounds (28-30) were found to be more potent than the standard drug benznidazole, with IC50/24h values between 6.8 and 80.8µM. Analysis of the toxicity to heart muscle cells led to LC50/24h of <125, 63.1 and 281.6µM for 28, 29 and 30, respectively. Displaying a selectivity index of 34.3, compound 30 will be further evaluated in vivo. The electrochemical properties of selected compounds were evaluated in an attempt to find correlations with trypanocidal activity, and it was observed that more electrophilic quinones were generally more potent.
Assuntos
Naftoquinonas/química , Triazóis/química , Tripanossomicidas/síntese química , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Cristalografia por Raios X , Técnicas Eletroquímicas , Eletrodos , Camundongos , Conformação Molecular , Miócitos Cardíacos/citologia , Relação Estrutura-Atividade , Triazóis/síntese química , Triazóis/toxicidade , Tripanossomicidas/química , Tripanossomicidas/toxicidade , Trypanosoma cruzi/efeitos dos fármacosRESUMO
Naphthoquinoidal compounds are of great interest in medicinal chemistry. In recent years, several synthetic routes have been developed to obtain bioactive molecules derived from lapachones. In this mini-review, we focus on the synthetic aspects and strategies used to design these compounds and on the biological activities of these substances for the development of drugs against the neglected diseases leishmaniasis and Chagas disease as well as malaria, tuberculosis and cancer. Three strategies used to develop bioactive naphthoquinoidal compounds are discussed: (i) C-ring modification, (ii) redox centre modification and (iii) A-ring modification. Among these strategies, reactions such as copper-catalysed azide-alkyne cycloaddition (click chemistry), palladium-catalysed cross couplings, and heterocyclisations will be discussed for the development of naphthoquinoidal compounds against Trypanosoma cruzi, Leishmania and cancer. The aim of derivatisation is the generation of novel molecules that inhibit cellular organelles/processes, generate reactive oxygen species (ROS) and increase lipophilicity to enhance penetration through the plasma membrane. Modified lapachones have emerged as promising prototypes for the development of drugs against neglected diseases and cancer.
Assuntos
Leishmania/efeitos dos fármacos , Naftoquinonas/síntese química , Naftoquinonas/farmacologia , Neoplasias/tratamento farmacológico , Trypanosoma cruzi/efeitos dos fármacos , Animais , Membrana Celular/química , Doença de Chagas/tratamento farmacológico , Humanos , Interações Hidrofóbicas e Hidrofílicas , Leishmaniose/tratamento farmacológico , Malária/tratamento farmacológico , Naftoquinonas/química , Espécies Reativas de Oxigênio/metabolismo , Tuberculose/tratamento farmacológicoRESUMO
BACKGROUND: Naphthoquinones (NQs) are privileged structures in medicinal chemistry due to the biological effects associated with the induction of oxidative stress. The present study evaluated the activities of sixteen NQs derivatives on Trypanosoma cruzi. RESULTS: Fourteen NQs displayed higher activity against bloodstream trypomastigotes of T. cruzi than benznidazole. Further assays with NQ1, NQ8, NQ9 and NQ12 showed inhibition of the proliferation of axenic epimastigotes and intracelulluar amastigotes interiorized in macrophages and in heart muscle cells. NQ8 was the most active NQ against both proliferative forms of T. cruzi. In epimastigotes the four NQs induced mitochondrial swelling, vacuolization, and flagellar blebbing. The treatment with NQs also induced the appearance of large endoplasmic reticulum profiles surrounding different cellular structures and of myelin-like membranous contours, morphological characteristics of an autophagic process. At IC50 concentration, NQ8 totally disrupted the ΔΨm of about 20% of the parasites, suggesting the induction of a sub-population with metabolically inactive mitochondria. On the other hand, NQ1, NQ9 or NQ12 led only to a discrete decrease of TMRE + labeling at IC50 values. NQ8 led also to an increase in the percentage of parasites labeled with DHE, indicative of ROS production, possibly the cause of the observed mitochondrial swelling. The other three NQs behaved similarly to untreated controls. CONCLUSIONS: NQ1, NQ8, NQ9 and NQ12 induce an autophagic phenotype in T. cruzi epimastigoted, as already observed with others NQs. The absence of oxidative stress in NQ1-, NQ9- and NQ12-treated parasites could be due to the existence of more than one mechanism of action involved in their trypanocidal activity, leaving ROS generation suppressed by the detoxification system of the parasite. The strong redox effect of NQ8 could be associated to the presence of the acetyl group in its structure facilitating quinone reduction, as previously demonstrated by electrochemical analysis. Further experiments using biochemical and molecular approaches are needed to better characterize ROS participation in the mechanism of action of these NQs.
Assuntos
Antiprotozoários/farmacologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Dilatação Mitocondrial , Naftoquinonas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Concentração Inibidora 50 , Macrófagos/efeitos dos fármacos , Macrófagos/parasitologia , Camundongos , Mitocôndrias/fisiologia , Testes de Sensibilidade ParasitáriaRESUMO
We report herein the synthesis and trypanocidal profile of new (E)-cinnamic N-acylhydrazones (NAHs) designed by exploiting molecular hybridization between the potent cruzain inhibitors (E)-1-(benzo[d][1,3]dioxol-5-yl)-3-(4-bromophenyl)prop-2-en-1-one and (E)-3-hydroxy-N'-((2-hydroxynaphthalen-1-yl)methylene)-7-methoxy-2-naphthohydrazide. These derivatives were evaluated against both amastigote and trypomastigote forms of Trypanosoma cruzi and lead us to identify two compounds that were approximately two times more active than the reference drug, benznidazole, and with good cytotoxic index. Although designed as cruzain inhibitors, the weak potency displayed by the best cinnamyl NAH derivatives indicated that another mechanism of action was likely responsible for their trypanocide action.
Assuntos
Cinamatos/química , Desenho de Fármacos , Hidrazonas/síntese química , Hidrazonas/farmacologia , Tripanossomicidas/síntese química , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Técnicas de Química Sintética , Cisteína Endopeptidases , Hidrazonas/química , Hidrazonas/toxicidade , Concentração Inibidora 50 , Camundongos , Proteínas de Protozoários/antagonistas & inibidores , Tripanossomicidas/química , Tripanossomicidas/toxicidade , Trypanosoma cruzi/enzimologiaRESUMO
Five 2-hydroxy-3-substituted-aminomethyl naphthoquinones, nine 1,2,3-triazolic para-naphthoquinones, five nor-ß-lapachone-based 1,2,3-triazoles, and several other naphthoquinonoid compounds were synthesized and evaluated against the infective bloodstream form of Trypanosoma cruzi, the etiological agent of Chagas disease, continuing our screening program for new trypanocidal compounds. Among all the substances, 16-18, 23, 25-29 and 30-33 were herein described for the first time and fifteen substances were identified as more potent than the standard drug benznidazole, with IC(50)/24h values in the range of 10.9-101.5 µM. Compounds 14 and 19 with Selectivity Index of 18.9 and 6.1 are important structures for further studies.
Assuntos
Técnicas de Química Sintética , Química Click , Descoberta de Drogas , Naftoquinonas/síntese química , Naftoquinonas/farmacologia , Triazóis/química , Trypanosoma cruzi/efeitos dos fármacos , Animais , Camundongos , Naftoquinonas/química , Naftoquinonas/toxicidade , Tripanossomicidas/síntese química , Tripanossomicidas/química , Tripanossomicidas/farmacologia , Tripanossomicidas/toxicidadeRESUMO
Trypanosoma cruzi is a hemoflagellate protozoan that causes Chagas' disease. The life cycle of T. cruzi is complex and involves different evolutive forms that have to encounter different environmental conditions provided by the host. Herein, we performed a functional assessment of mitochondrial metabolism in the following two distinct evolutive forms of T. cruzi: the insect stage epimastigote and the freshly isolated bloodstream trypomastigote. We observed that in comparison to epimastigotes, bloodstream trypomastigotes facilitate the entry of electrons into the electron transport chain by increasing complex II-III activity. Interestingly, cytochrome c oxidase (CCO) activity and the expression of CCO subunit IV were reduced in bloodstream forms, creating an "electron bottleneck" that favored an increase in electron leakage and H(2)O(2) formation. We propose that the oxidative preconditioning provided by this mechanism confers protection to bloodstream trypomastigotes against the host immune system. In this scenario, mitochondrial remodeling during the T. cruzi life cycle may represent a key metabolic adaptation for parasite survival in different hosts.
Assuntos
Complexo III da Cadeia de Transporte de Elétrons/metabolismo , Complexo II de Transporte de Elétrons/metabolismo , Estágios do Ciclo de Vida/fisiologia , Mitocôndrias/metabolismo , Proteínas de Protozoários/metabolismo , Trypanosoma cruzi/metabolismo , Adaptação Fisiológica/fisiologia , Animais , Doença de Chagas/imunologia , Doença de Chagas/metabolismo , Doença de Chagas/parasitologia , Complexo II de Transporte de Elétrons/imunologia , Complexo III da Cadeia de Transporte de Elétrons/imunologia , Humanos , Peróxido de Hidrogênio/imunologia , Peróxido de Hidrogênio/metabolismo , Mitocôndrias/imunologia , Proteínas de Protozoários/imunologia , Trypanosoma cruzi/crescimento & desenvolvimento , Trypanosoma cruzi/imunologiaRESUMO
Chagas disease (CD), caused by Trypanosoma cruzi, affects approximately eight million individuals in Latin America and is emerging in nonendemic areas due to the globalisation of immigration and nonvectorial transmission routes. Although CD represents an important public health problem, resulting in high morbidity and considerable mortality rates, few investments have been allocated towards developing novel anti-T. cruzi agents. The available therapy for CD is based on two nitro derivatives (benznidazole (Bz) and nifurtimox (Nf)) developed more than four decades ago. Both are far from ideal due to substantial secondary side effects, limited efficacy against different parasite isolates, long-term therapy, and their well-known poor activity in the late chronic phase. These drawbacks justify the urgent need to identify better drugs to treat chagasic patients. Although several classes of natural and synthetic compounds have been reported to act in vitro and in vivo on T. cruzi, since the introduction of Bz and Nf, only a few drugs, such as allopurinol and a few sterol inhibitors, have moved to clinical trials. This reflects, at least in part, the absence of well-established universal protocols to screen and compare drug activity. In addition, a large number of in vitro studies have been conducted using only epimastigotes and trypomastigotes instead of evaluating compounds' activities against intracellular amastigotes, which are the reproductive forms in the vertebrate host and are thus an important determinant in the selection and identification of effective compounds for further in vivo analysis. In addition, due to pharmacokinetics and absorption, distribution, metabolism, and excretion characteristics, several compounds that were promising in vitro have not been as effective as Nf or Bz in animal models of T. cruzi infection. In the last two decades, our team has collaborated with different medicinal chemistry groups to develop preclinical studies for CD and investigate the in vitro and in vivo efficacy, toxicity, selectivity, and parasite targets of different classes of natural and synthetic compounds. Some of these results will be briefly presented, focusing primarily on diamidines and related compounds and naphthoquinone derivatives that showed the most promising efficacy against T. cruzi.