RESUMEN
Infections with protozoan parasites are a major cause of disease and mortality in many tropical countries of the world. Diseases caused by species of the genera Trypanosoma (Human African Trypanosomiasis and Chagas Disease) and Leishmania (various forms of Leishmaniasis) are among the seventeen "Neglected Tropical Diseases" (NTDs) defined by the WHO. Furthermore, malaria (caused by various Plasmodium species) can be considered a neglected disease in certain countries and with regard to availability and affordability of the antimalarials. Living organisms, especially plants, provide an innumerable number of molecules with potential for the treatment of many serious diseases. The current review attempts to give an overview on the potential of such plant-derived natural products as antiprotozoal leads and/or drugs in the fight against NTDs. In part I, a general description of the diseases, the current state of therapy and need for new therapeuticals, assay methods and strategies applied in the search for new plant derived natural products against these diseases and an overview on natural products of terpenoid origin with antiprotozoal potential were given. The present part II compiles the current knowledge on natural products with antiprotozoal activity that are derived from the shikimate pathway (lignans, coumarins, caffeic acid derivatives), quinones of various structural classes, compounds formed via the polyketide pathways (flavonoids and related compounds, chromenes and related benzopyrans and benzofurans, xanthones, acetogenins from Annonaceae and polyacetylenes) as well as the diverse classes of alkaloids. In total, both parts compile the literature on almost 900 different plant-derived natural products and their activity data, taken from over 800 references. These data, as the result of enormous efforts of numerous research groups world-wide, illustrate that plant secondary metabolites represent an immensely rich source of chemical diversity with an extremely high potential to yield a wealth of lead structures towards new therapies for NTDs. Only a small percentage, however, of the roughly 200,000 plant species on earth have been studied chemically and only a small percentage of these plants or their constituents has been investigated for antiprotozoal activity. The repository of plant-derived natural products hence deserves to be investigated even more intensely than it has been up to present.
Asunto(s)
Antiprotozoarios/uso terapéutico , Productos Biológicos/uso terapéutico , Enfermedades Desatendidas/tratamiento farmacológico , Extractos Vegetales/uso terapéutico , Plantas Medicinales/química , Infecciones por Protozoos/tratamiento farmacológico , Animales , Antiprotozoarios/química , Antiprotozoarios/metabolismo , Productos Biológicos/química , Productos Biológicos/metabolismo , Humanos , Fitoterapia , Extractos Vegetales/química , Extractos Vegetales/metabolismo , Plantas Medicinales/metabolismoRESUMEN
Infections with protozoan parasites are a major cause of disease and mortality in many tropical countries of the world. Diseases caused by species of the genera Trypanosoma (Human African Trypanosomiasis and Chagas Disease) and Leishmania (various forms of Leishmaniasis) are among the seventeen "Neglected Tropical Diseases" (NTDs) defined as such by WHO due to the neglect of financial investment into research and development of new drugs by a large part of pharmaceutical industry and neglect of public awareness in high income countries. Another major tropical protozoan disease is malaria (caused by various Plasmodium species), which -although not mentioned currently by the WHO as a neglected disease- still represents a major problem, especially to people living under poor circumstances in tropical countries. Malaria causes by far the highest number of deaths of all protozoan infections and is often (as in this review) included in the NTDs. The mentioned diseases threaten many millions of lives world-wide and they are mostly associated with poor socioeconomic and hygienic environment. Existing therapies suffer from various shortcomings, namely, a high degree of toxicity and unwanted effects, lack of availability and/or problematic application under the life conditions of affected populations. Development of new, safe and affordable drugs is therefore an urgent need. Nature has provided an innumerable number of drugs for the treatment of many serious diseases. Among the natural sources for new bioactive chemicals, plants are still predominant. Their secondary metabolism yields an immeasurable wealth of chemical structures which has been and will continue to be a source of new drugs, directly in their native form and after optimization by synthetic medicinal chemistry. The current review, published in two parts, attempts to give an overview on the potential of such plant-derived natural products as antiprotozoal leads and/or drugs in the fight against NTDs.
Asunto(s)
Antiprotozoarios/uso terapéutico , Productos Biológicos/uso terapéutico , Enfermedades Desatendidas/tratamiento farmacológico , Extractos Vegetales/uso terapéutico , Plantas Medicinales/química , Plantas Medicinales/metabolismo , Infecciones por Protozoos/tratamiento farmacológico , Animales , Antiprotozoarios/química , Antiprotozoarios/metabolismo , Productos Biológicos/química , Productos Biológicos/metabolismo , Humanos , Fitoterapia , Extractos Vegetales/química , Extractos Vegetales/metabolismoRESUMEN
Chagas' disease, caused by the protozoan Trypanosoma cruzi, represents a serious health problem in Latin America, and the available chemotherapy, which is based on 2 nitro-derivatives, is not satisfactory. In folk medicine, natural products including naphthoquinones have been employed for the treatment of different parasitic diseases. In the pursuit of alternative drugs for Chagas' disease, we investigated the mechanism of action of the triazolic naphthoquinone (TN; 2,2-dimethyl-3-(4-phenyl-1H-1,2,3-triazol-1-yl)-2,3-dihydronaphtho[1,2-b]furan-4,5-dione), which is the most active compound against T. cruzi trypomastigotes among a series of naphthofuranquinones. TN was active against the 3 parasite forms producing a dose-dependent inhibitory effect. In epimastigotes, TN induced reservosome disruption, flagellar blebbing, Golgi disorganization, the presence of cytosolic concentric membrane structures and abnormal multiflagellar parasites. The treatment also led to the appearance of well-developed endoplasmic reticulum profiles surrounding organelles that associated with an increase in monodansylcadaverine labelling, suggesting autophagy as part of the TN mechanism of action. Interestingly, no ultrastructural damage was detected in the mitochondria of naphthoquinone-treated epimastigotes. Flow cytometric analysis demonstrated an impairment of mitosis, an increase in ROS production and the maintenance of mitochondrial membrane potential. TN could be a good starting point in the investigation of a chemotherapeutic approach for the treatment of Chagas' disease.
Asunto(s)
Naftoquinonas/farmacología , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Autofagia/efectos de los fármacos , Citometría de Flujo , Concentración 50 Inhibidora , Macrófagos Peritoneales/efectos de los fármacos , Ratones , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Mitosis/efectos de los fármacos , Orgánulos/efectos de los fármacosRESUMEN
Infections with protozoan parasites are a major cause of disease and mortality in many tropical countries of the world. Diseases caused by species of the genera Trypanosoma (Human African Trypanosomiasis and Chagas Disease) and Leishmania (various forms of Leishmaniasis) are among the seventeen "Neglected Tropical Diseases" (NTDs) defined as such by WHO due to the neglect of financial investment into research and development of new drugs by a large part of pharmaceutical industry and neglect of public awareness in high income countries. Another major tropical protozoan disease is malaria (caused by various Plasmodium species), which -although not mentioned currently by the WHO as a neglected disease- still represents a major problem, especially to people living under poor circumstances in tropical countries. Malaria causes by far the highest number of deaths of all protozoan infections and is often (as in this review) included in the NTDs. The mentioned diseases threaten many millions of lives world-wide and they are mostly associated with poor socioeconomic and hygienic environment. Existing therapies suffer from various shortcomings, namely, a high degree of toxicity and unwanted effects, lack of availability and/or problematic application under the life conditions of affected populations. Development of new, safe and affordable drugs is therefore an urgent need. Nature has provided an innumerable number of drugs for the treatment of many serious diseases. Among the natural sources for new bioactive chemicals, plants are still predominant. Their secondary metabolism yields an immeasurable wealth of chemical structures which has been and will continue to be a source of new drugs, directly in their native form and after optimization by synthetic medicinal chemistry. The current review, published in two parts, attempts to give an overview on the potential of such plant-derived natural products as antiprotozoal leads and/or drugs in the fight against NTDs.
Asunto(s)
Plantas Medicinales/metabolismo , Plantas Medicinales/química , Infecciones por Protozoos/tratamiento farmacológico , Productos Biológicos/metabolismo , Productos Biológicos/uso terapéutico , Productos Biológicos/química , Humanos , Extractos Vegetales/metabolismo , Extractos Vegetales/uso terapéutico , Extractos Vegetales/química , Animales , Fitoterapia , Antiprotozoarios/metabolismo , Antiprotozoarios/uso terapéutico , Antiprotozoarios/químicaRESUMEN
Due to limited efficacy and considerable toxicity, the therapy for Chagas' disease is far from being ideal, and thus new compounds are desirable. Diamidines and related compounds such as arylimidamides have promising trypanocidal activity against Trypanosoma cruzi. To better understand the mechanism of action of these heterocyclic cations, we investigated the kinetoplast DNA (kDNA) binding properties and trypanocidal efficacy against T. cruzi of 13 compounds. Four diamidines (DB75, DB569, DB1345, and DB829), eight arylimidamides (DB766, DB749, DB889, DB709, DB613, DB1831, DB1852, and DB2002), and one guanylhydrazone (DB1080) were assayed in thermal denaturation (T(m)) and circular dichroism (CD) studies using whole purified T. cruzi kDNA and a conserved synthetic parasite sequence. The overall CD spectra using the whole kDNA were similar to those found for the conserved sequence and were indicative of minor groove binding. Our findings showed that some of the compounds that exhibited the highest trypanocidal activities (e.g., DB766) caused low or no change in the T(m) measurements. However, while some active compounds, such as DB766, induced profound alterations of kDNA topology, others, like DB1831, although effective, did not result in altered T(m) and CD measurements. Our data suggest that the strong affinity of amidines with kDNA per se is not sufficient to generate and trigger their trypanocidal activity. Cell uptake differences and possibly distinct cellular targets need to be considered in the final evaluation of the mechanisms of action of these compounds.
Asunto(s)
Amidinas/metabolismo , Amidinas/farmacología , ADN de Cinetoplasto/metabolismo , Tripanocidas/metabolismo , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Amidinas/química , Secuencia Conservada , ADN de Cinetoplasto/química , Relación Dosis-Respuesta a Droga , Pruebas de Sensibilidad Parasitaria , Relación Estructura-Actividad , Termodinámica , Tripanocidas/químicaRESUMEN
El crecimiento es una de las características de naturaleza cuantitativa que influye en la calidad de la canal. En el presente estudio se identificaron las regiones cromosomales responsables para la variación del crecimiento en el cromosoma 5 en una población de ganado criollo romosinuano. Se evaluaron en 72 progenies las características de peso alnacimiento, peso al destete, peso a los 12 meses y a los 16 meses, área de ojo del lomo alos 12 y 16 meses, espesor de grasa dorsal a los 12 y 16 meses, espesor de grasa del anca a los 12 y 16 meses, ganancia diaria predestete y posdestete, al igual que los genotipos de tres polimorfismos de nucleótido simple de los genes MYF5, PDE1B e IGF1 y decuatro microsatélites BM6026, CSSM34, RM500, ETH10, distribuidos a lo largo del cromosoma. Se realizó un análisis de regresión linear el cual mostró el efecto de seis loci de rasgos cuantitativos (QTL) asociados a características de crecimiento. Cinco QTL fueron significativos (p≤0,05) para las características de peso al nacimiento, peso a los16 meses, área del ojo de lomo a los 12 y 16 meses y ganancia diaria posdestete y un QTL se encontró con una significancia de p≤0,01 para la característica ganancia diaria predestete. Los resultados demostraron que los genes MYF5, PDE1B, IGF1 pueden ser genes candidatos posicionales que inciden en la variación del crecimiento para la calidad de la canal en el ganado romosinuano.
Growth is a quantitative trait that influences the carcass quality. In the present study, bovine chromosomal 5 regions responsible for growth variations have been identified in a Romosinuano creole cattle population. The traits birth weight, weaning weight,12 months weight, 16 months weight, the rib eye area at 12 and 16 months, back fatthickness at 12 and 16 months, rump fat thickness at 12 and 16 months, preweaning and postweaning daily gain were evaluated in 72 progenies, as well as the genotypes of 3 SNPs from the MYF5, PDE1B, IGF1 genes and 4 microsatellites (BM6026,CSSM34, RM500, ETH10) distributed along the chromosome. A linear regression analysis showed the six QTL effect associated with growth traits. Five QTL were significant at p≤0.05 for the triait birth weight, weight at 16 months, rib eye area at 12 and 16 months, and preweaning daily gain interval between 45 and 105 cM and aQTL showed a level significance of p ≤ 0.01 for the postweaning daily gain. It was demostrated according to the position of the QTLs identified in the present study, that the MYF5, PDE1B and IGF1 genes might be positional candidate genes affecting the growth variation for carcass quality in Romosinuano cattle.
Asunto(s)
Animales , Bovinos/genética , Ligamiento Genético , UltrasonidoRESUMEN
From a series of 1,3,4-thiadiazole-2-arylhydrazone derivatives of megazol screened in vitro against Trypanosoma cruzi, eight (S1 to S8) were selected for in vivo screening by single-dose oral administration (200 mg/kg of body weight) to infected mice at 5 days postinfection (dpi). Based on significant decreases in both parasitemia levels and mortality rates, S2 and S3 were selected for further assays. Despite having no in vivo effect, S1 was included since it was 2-fold more potent against trypomastigotes than megazol in vitro. Trypomastigotes treated with S1, S2, or S3 showed alterations of the flagellar structure and of the nuclear envelope. When assayed on intracellular amastigotes, the selectivity index (SI) for macrophages was in the range of >27 to >63 and for cardiac cells was >32 for S1 and >48 for megazol. In noninfected mice, S1 did not alter the levels of glutamic oxalacetic transaminase (GOT), glutamate pyruvate transaminase (GPT), or urea. S2 led to an increase in GOT, S3 to increases in GOT and GPT, and megazol to an increase in GOT. Infected mice were treated with each derivative at 50 and 100 mg/kg from dpi 6 to 15: S1 did not interfere with the course of infection or reduce the number of inflammatory foci in the cardiac tissue, S2 led to a significant decrease of parasitemia, and S3 decreased mortality. There was no direct correlation between the in vitro effect on trypomastigotes and amastigotes and the results of the treatment in experimental models, as S1 showed a high potency in vitro while, in two different schemes of in vivo treatment, no decrease of parasitemia or mortality was observed.
Asunto(s)
Enfermedad de Chagas/tratamiento farmacológico , Hidrazonas/farmacología , Tiadiazoles/farmacología , Trypanosoma cruzi/efectos de los fármacos , Alanina Transaminasa/sangre , Animales , Antiprotozoarios/química , Antiprotozoarios/farmacología , Aspartato Aminotransferasas/sangre , Peso Corporal , Células Cultivadas , Enfermedad de Chagas/mortalidad , Enfermedad de Chagas/parasitología , Hidrazonas/química , Técnicas In Vitro , Concentración 50 Inhibidora , Macrófagos Peritoneales/citología , Macrófagos Peritoneales/parasitología , Masculino , Ratones , Microscopía Electrónica de Rastreo , Miocitos Cardíacos/citología , Miocitos Cardíacos/parasitología , Parasitemia/tratamiento farmacológico , Parasitemia/mortalidad , Parasitemia/parasitología , Tiadiazoles/química , Trypanosoma cruzi/crecimiento & desarrollo , Trypanosoma cruzi/ultraestructura , Urea/sangreRESUMEN
SUMMARY: In a screening of 65 derivatives of natural quinones using bloodstream trypomastigotes of Trypanosoma cruzi, the 3 naphthoimidazoles derived from beta-lapachone - N1, N2 and N3--were selected as the most active. Investigation of their mode of action led to the characterization of mitochondrion, reservosomes and DNA as their main targets, and stimulated further studies on death pathways. Ultrastructural analysis revealed both autophagic (autophagosomes) and apoptotic-like (membrane blebbing) phenotypes. Flow cytometry analysis showed, in N2-treated trypomastigotes, a small increase of phosphatidylserine exposure, and a large increase in the percentage of necrosis, caused by N1 or N2. These death phenotypes were not detected in treated epimastigotes. The strong increase in labelling of monodansyl cadaverine, the inhibition of the death process by wortmannin or 3-methyladenine, the overexpression of ATG genes in treated epimastigotes, together with ultrastructural evidence point to autophagy as the predominant phenotype induced by the naphthoimidazoles. However, there are other pathways occurring concomitantly with variable intensities, justifying the need to detail the molecular features involved.
Asunto(s)
Autofagia/efectos de los fármacos , Imidazoles/farmacología , Naftoquinonas/farmacología , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Membrana Celular/efectos de los fármacos , Membrana Celular/ultraestructura , Citometría de Flujo , Imidazoles/síntesis química , Imidazoles/química , Microscopía Electrónica , Naftoquinonas/síntesis química , Naftoquinonas/química , Pruebas de Sensibilidad Parasitaria , Fenotipo , Tripanocidas/síntesis química , Tripanocidas/química , Trypanosoma cruzi/genética , Trypanosoma cruzi/crecimiento & desarrollo , Trypanosoma cruzi/ultraestructuraRESUMEN
Electron microscopy may be useful in chemotherapy studies at distinct levels, such as the identification of subcellular targets in the parasites and the elucidation of the ultimate drug mechanism of action, inferred by the alterations induced by antiparasitic compounds. In this review we present data obtained by electron microscopy approaches of different parasitic protozoa, such as Trypanosoma cruzi, Leishmania spp., Giardia lamblia and trichomonads, under the action of drugs, demonstrating that the cell architecture organization is only determined in detail at the ultrastructural level. The transmission electron microscopy may shed light (i.e. electrons) not only on the affected compartment, but also on the manner it is altered, which may indicate presumable target metabolic pathways as well as the actual toxic or lethal effects of a drug. Cytochemical and analytical techniques can provide valuable information on the composition of the altered cell compartment, permitting the bona fide identification of the drug target and a detailed understanding of the mechanism underneath its effect. Scanning electron microscopy permits the recognition of the drug-induced alterations on parasite surface and topography. Such observations may reveal cytokinetic dysfunctions or membrane lesions not detected by other approaches. In this context, electron microscopy techniques comprise valuable tools in chemotherapy studies.
Asunto(s)
Antiprotozoarios/farmacología , Eucariontes/efectos de los fármacos , Microscopía Electrónica/métodos , Animales , Sistemas de Liberación de Medicamentos , Eucariontes/ultraestructura , Humanos , Infecciones por Protozoos/tratamiento farmacológico , Infecciones por Protozoos/parasitologíaRESUMEN
BACKGROUND: The Frontal Assessment Battery (FAB) is a short tool for the assessment of executive functions consisting of six subtests that explore different abilities related to the frontal lobes. Several studies have indicated that executive dysfunction is the main neuropsychological feature in Parkinson's disease (PD). GOALS: To evaluate the clinical usefulness of the FAB in identifying executive dysfunction in PD; to determine if FAB scores in PD are correlated with formal measures of executive functions; and to provide normative data for the Portuguese version of the FAB. METHODS: The study involved 122 healthy participants and 50 idiopathic PD patients. We compared FAB scores in normal controls and in PD patients matched for age, education and Mini-Mental State Examination (MMSE) score. In PD patients, FAB results were compared to the performance on tests of executive functioning. RESULTS: In the healthy subjects, FAB scores varied as a function of age, education and MMSE. In PD, FAB scores were significantly decreased compared to normal controls, and correlated with measures of executive functions such as phonemic and semantic verbal fluency tests, Wisconsin Card Sorting Test and Trail Making Test Part A and Part B. CONCLUSION: The FAB is a useful tool for the screening of executive dysfunction in PD, showing good discriminant and concurrent validities. Normative data provided for the Portuguese version of this test improve the accuracy and confidence in the clinical use of the FAB.
Asunto(s)
Procesos Mentales , Pruebas Neuropsicológicas , Enfermedad de Parkinson/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Análisis de Varianza , Cognición , Humanos , Persona de Mediana Edad , Enfermedad de Parkinson/psicología , Portugal , Adulto JovenRESUMEN
In the search for new therapeutic agents for Chagas' disease, we screened extracts obtained from the Brazilian plant Pterodon pubescens found commercially in the medicinal flora market. We investigated the potential trypanocidal effect of the oleaginous ethanolic extract of P. pubescens seeds and its fractions (PF1, PF1.1, PF1.2, and PF1.3) and of geranylgeraniol (GG-OH), the sole component of the hexane fraction (PF1.2). In experiments with bloodstream trypomastigotes of Trypanosoma cruzi, performed at 37 degrees C in culture medium, PF1.2 and GG-OH showed similar potency, while the oleaginous extract from P. pubescens seeds and the other fractions were about three times less active. GG-OH inhibited the proliferation of intracellular amastigotes, at concentrations which do not affect the mammalian host cell. Transmission electron microscopy and flow cytometry analysis indicate the mitochondrion, an organelle that plays a central role in apoptosis, of both epimastigotes and of trypomastigotes as the major target of GG-OH. On the other hand, the ultrastructural images of the endoplasmic reticulum profiles, myelin-like figures, and concentric membranous arrangements inside damaged mitochondrion are suggestive of an autophagic pathway leading to parasite death. Because the different forms of cell death share some morphological features such as mitochondrial collapse, further studies are needed to disclose the trypanocidal action of GG-OH.
Asunto(s)
Diterpenos/farmacología , Fabaceae/química , Aceites de Plantas/farmacología , Semillas/química , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Diterpenos/química , Relación Dosis-Respuesta a Droga , Aceites de Plantas/química , Factores de Tiempo , Tripanocidas/química , Trypanosoma cruzi/ultraestructuraRESUMEN
Aromatic diamidines and related compounds are DNA minor groove binders that have been screened against a variety of pathogenic microorganisms such as bacteria, fungi and protozoa and show promising results. Parasitic infections are widespread in developing countries and are major contributors to human mortality and morbidity, causing considerable economic hardship. Trypanosomes are unicellular protozoan organisms that cause serious public health problems in developing countries: African trypanosomiasis (sleeping sickness) in Africa, and Chagas' disease, in Latin America. Sleeping sickness, caused by sub-species of Trypanosome brucei (T. brucei gambiense and T. brucei rhodesiense), is a fatal disease if left untreated, with about 60 million people currently at risk. Trypanosoma cruzi is the etiological agent of Chagas' disease, an important parasitic illness that affects nearly 17 million individuals in endemic areas. The fact that the available clinical drugs are expensive, toxic, require long treatment periods, frequently exhibit reduced activity towards certain parasite strains and evolutive stages, and are beginning to show development of resistance, demonstrates the urgent need for the development of new drugs for both pathologies. For some time much attention has been focused on the effect of diamidines (and related compounds) on African trypanosomes. However more recent studies have pointed to their potential activity against T.cruzi. In this review the current therapeutic state of the art of aromatic diamidines and related compounds used against T.brucei and T.cruzi is reviewed with a focus on their potential use as antiparasitic drugs for the treatment of both these important neglected diseases.
Asunto(s)
Pentamidina/uso terapéutico , Tripanocidas/uso terapéutico , Tripanosomiasis Africana/tratamiento farmacológico , Animales , Enfermedad de Chagas/tratamiento farmacológico , Resistencia a Medicamentos , Humanos , Pentamidina/química , Pentamidina/farmacología , Tripanocidas/química , Trypanosoma brucei brucei/efectos de los fármacos , Trypanosoma cruzi/efectos de los fármacosRESUMEN
This study describes the design, synthesis and trypanocidal evaluation of new azaheterocyclic derivatives (4-8). These compounds were designed as megazol (1) analogs based on bioisosterism tools and were synthesized to investigate the possible pharmacophoric contribution of the 1,2,4-triazole nucleus, the position of the heterocyclic nucleus and presence of the nitro group, to the activity against the bloodstream trypomastigote forms of Trypanosoma cruzi. The most potent compound was 6, a nitro derivative obtained by substitution of a thiadiazole by a triazole ring and by moving the nitro group from C-5 position, as in 1, to the C-4 position. Finally, we have used semi-empirical theoretical calculations to discuss the correlation of some stereo electronic properties with biological activity in an attempt to understand the possible mechanism of action of the designed series of compounds.
Asunto(s)
Compuestos Aza/síntesis química , Compuestos Aza/farmacología , Compuestos Heterocíclicos/síntesis química , Compuestos Heterocíclicos/farmacología , Tiadiazoles/síntesis química , Tiadiazoles/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Espectroscopía de Resonancia Magnética , Espectrometría de MasasRESUMEN
Three naphthoimidazoles presenting aromatic groups attached to the imidazole ring were the most active against trypomastigotes of Trypanosoma cruzi between 45 derivatives from beta-lapachone. N1 is active against the three forms of the parasite. In this work, we investigated N2 and N3 and analyzed the effect of the three derivatives on metacyclogenesis, endocytosis, and cell cycle. In epimastigotes, N2 and N3 blocked the cell cycle, inhibited succinate cytochrome c reductase, metacyclogenesis, and induced damage to mitochondrion, Golgi, and reservosomes. In treated trypomastigotes, there were alterations in the mitochondrion, nucleus and kinetoplast, and DNA fragmentation. Preincubation with cysteine protease inhibitors reversed the effect of N1, N2, and N3. Such reversion and ultrastructural alterations suggest the involvement of autophagy in parasite death. Ultrastructural, flow cytometry, and biochemical studies suggest that naphthoimidazoles interferes with the energetic metabolism and induces DNA fragmentation.
Asunto(s)
Antiprotozoarios/farmacología , Bignoniaceae/química , Fragmentación del ADN/efectos de los fármacos , Imidazoles/farmacología , Mitocondrias/efectos de los fármacos , Naftoquinonas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Antiprotozoarios/síntesis química , Antiprotozoarios/química , Ciclo Celular/efectos de los fármacos , ADN Mitocondrial/efectos de los fármacos , Endocitosis/efectos de los fármacos , Imidazoles/síntesis química , Imidazoles/química , Concentración 50 Inhibidora , Ratones , Microscopía Electrónica de Rastreo , Naftoquinonas/síntesis química , Naftoquinonas/química , Pruebas de Sensibilidad Parasitaria , Trypanosoma cruzi/citología , Trypanosoma cruzi/crecimiento & desarrollo , Trypanosoma cruzi/ultraestructuraRESUMEN
We have previously reported that epimastigote forms of Trypanosoma cruzi treated with the lysophospholipid analogues (LPAs) edelfosine (ET-18), ilmofosine, and miltefosine suffered alterations in plasma membrane, mitochondrion, and lipid synthesis. In this work, ET-18 induced membrane damage in trypomastigotes and amastigotes. Incubation of epimastigotes and trypomastigotes with the three LPAs led to membrane permeabilization, which was abolished by serum addition. Treatment for 24 h in culture medium interfered the with mitochondrial status of epimastigotes, with no effect in trypomastigotes, in agreement with ultrastructural data. LPAs induced alterations in the plasma membrane of the three forms of T. cruzi and in the mitochondria of epimastigotes, suggesting that these organelles are potential targets of these analogues.
Asunto(s)
Enfermedad de Chagas/tratamiento farmacológico , Inhibidores de Fosfodiesterasa/uso terapéutico , Éteres Fosfolípidos/uso terapéutico , Trypanosoma cruzi/ultraestructura , Animales , Humanos , Microscopía Electrónica , Trypanosoma cruzi/efectos de los fármacos , Trypanosoma cruzi/crecimiento & desarrolloRESUMEN
The cis and trans isomers (either E or Z isomers) of the unsubstituted and bromo-2-propen-1-amine derivatives were evaluated in vitro on Trypanosoma cruzi. The results showed that cis is the most active isomeric form against trypomastigote forms of T. cruzi, indicating that it may contribute most to the trypanocidal effect. All mice which received 5 mg kg(-1) daily for 9 consecutive days, or 200 mg kg(-1) in a single dose of the bromo derivative of 2-propen-1-amine, survived after an infection with 10(4) trypomastigotes/ml of the Y-strain of T. cruzi. They also had a significantly lower parasitemia than the controls. However, with 100 mg kg(-1) of benznidazol for 9 consecutive days, 25% of the animals died by the end of the evaluation 40 days after infection. The involvement of the biosynthesis of ergosterol in the trypanocidal effect of the unsubstituted 2-propen-1-amine derivative was investigated on proliferative epimastigote forms of the parasite. The chromatographic analyses of the lipid extracts obtained from parasites treated with 2-propen-1-amine derivatives and controls (not treated) revealed that growth inhibition is correlated with the accumulation of squalene and the decrease of ergosterol levels. These results suggest that inhibition of the biosynthesis of ergosterol is an important target for the action of the 2-propen-1-amine derivative on T. cruzi through the inhibition of the enzyme squalene epoxidase.
Asunto(s)
Enfermedad de Chagas/tratamiento farmacológico , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Aminas/química , Aminas/farmacología , Aminas/uso terapéutico , Animales , Enfermedad de Chagas/mortalidad , Enfermedad de Chagas/parasitología , Medios de Cultivo , Humanos , Masculino , Ratones , Trypanosoma cruzi/genéticaRESUMEN
AIMS: The chemical composition of ethanol extracts from a Brazilian (Et-Bra) and a Bulgarian (Et-Blg) propolis, and their activity against the protozoan Trypanosoma cruzi, several fungi and bacteria species were determined. METHODS AND RESULTS: The chemical composition was determined by high temperature high resolution gas chromatography coupled to mass spectrometry. Microbiological activity was assayed in vitro against T. cruzi, Candida albicans, Sporothrix schenckii, Paracoccidioides brasiliensis, Neisseria meningitidis, Streptococcus pneumoniae and Staphylococcus aureus. CONCLUSIONS: Et-Bra and Et-Blg, although with totally distinct compositions, were active against T. cruzi and the three species of fungi. Et-Blg was more effective than Et-Bra against bacteria, particularly N. meningitidis and Strep. pneumoniae. SIGNIFICANCE AND IMPACT OF THE STUDY: Although with different classes of components, both propolis extracts showed microbicidal activity. For the bactericidal activity it was possible to establish a positive correlation with the high content of flavonoids of the Bulgarian extract.
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Antiinfecciosos/farmacología , Bacterias/efectos de los fármacos , Hongos/efectos de los fármacos , Própolis/química , Própolis/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Brasil , Bulgaria , Candida albicans/efectos de los fármacos , Flavonoides/química , Cromatografía de Gases y Espectrometría de Masas , Pruebas de Sensibilidad Microbiana , Neisseria meningitidis/efectos de los fármacos , Paracoccidioides/efectos de los fármacos , Pruebas de Sensibilidad Parasitaria , Sporothrix/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Streptococcus pneumoniae/efectos de los fármacosRESUMEN
The potential activity of three new derivatives of 3-(4'-Y-[1,1'-biphenyl]-4-yl)-3-(4-X-phenyl)-N,N-dimethyl-2-propen-1-amine (2-PAMs) was assayed against Trypanosoma cruzi and Leishmania amazonensis. They showed higher activity against trypomastigotes and epimastigotes of T. cruzi than the standard drugs, crystal violet and nifurtimox. Besides these derivatives, a series of eleven 2-PAMs derivatives and the corresponding intermediates, biphenyl methanones (BPMs) were assayed against promastigotes of L. amazonensis, showing that the 2-PAMs were remarkably more active than the BPMs. The PAMs 2c, 2e and 2j were about 2-fold more active that pentamidine isothionate and between 27.2- and 46.4-fold less toxic to V79 mammalian cells. The present results encourage further studies, especially against intracellular parasites and in experimental animals.
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Leishmania/efectos de los fármacos , Leishmaniasis/tratamiento farmacológico , Propilaminas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Pruebas de Sensibilidad ParasitariaRESUMEN
Microtubules play fundamental roles in eukaryotic cells and have been investigated as target for drugs. Several studies showed the potential use of anti-microtubule agents against pathogenic protozoa. Taxol has been intensively studied in Leishmania spp. and microtubules have been considered as a promising antileishmanial drug target. It has been also shown that taxol interferes with the proliferation of Trypanosoma cruzi, leading to morphological alterations and interruption of nuclear division and cytokinesis. In the present work we show that T. cruzi bloodstream trypomastigotes were much more susceptible than epimastigotes, and in both forms taxol caused severe ultrastructural damage, especially associated to changes in the shape of the parasites. In trypomastigotes, different degrees of body contortion along the longitudinal axis and a marked dilatation of the flagellar pocket were detected. Treated epimastigotes presented a decrease in the electron density of the mitochondrial matrix, absence of mitochondrial cristae and an increase in the number of lipid droplets. Bizarre multi-flagellar epimastigotes were also detected, suggesting an interruption of the cytokinesis. Taxol caused no noticeable ultrastructural alterations on sub-pellicular and flagellar microtubules of both evolutive forms of T. cruzi. As already described in the literature, such structures in trypanosomatids are very resistant to microtubule disrupters when compared to those in mammalian cells. Taxol prevented the endocytosis of albumin-gold complexes by epimastigotes, and this result could be associated to the loss of the dynamic stability of the microtubules of the cytostome.
Asunto(s)
Microtúbulos/efectos de los fármacos , Paclitaxel/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Relación Dosis-Respuesta a Droga , Endocitosis/efectos de los fármacos , Endocitosis/fisiología , Microscopía Electrónica de Rastreo , Microtúbulos/ultraestructura , Trypanosoma cruzi/crecimiento & desarrollo , Trypanosoma cruzi/ultraestructuraRESUMEN
We investigated the effect of 17beta-estradiol on mice resistant to infection by Trypanosoma cruzi. Infected Balb/C, C3H and C57BL/6 female mice had a longer survival time than males, C57BL/6 showing the highest difference (50% cumulative mortality in females versus 100% in males). This lineage was treated with estradiol (from 0.05 microg to 500 microg/mouse) 1 day before infection. Treatment with 50 microg or 500 microg estradiol/ mouse increased mortality and parasitaemia. Low doses had no effect or tended to reduce both parameters. Given that estradiol presented no in vitro effect on trypomastigotes or epimastigotes, the involvement of a direct hormonal effect on the parasite is improbable. Alterations in the humoral T. cruzi-specific response were also discarded, since the kinetics and concentration of anti-T. cruzi IgG were not affected by the treatment. Females infected during an estradiol-descending phase (meta-oestrus) survived longer than those infected during other phases of the oestrous cycle. We confirmed that estradiol interferes with T. cruzi infection.