RESUMO
Entamoeba histolytica (protozoan; family Endomoebidae) is the cause of amoebiasis, a disease related to high morbidity and mortality. Nowadays, this illness is considered a significant public health issue in developing countries. In addition, parasite resistance to conventional medicinal treatment has increased in recent years. Traditional medicine around the world represents a valuable source of alternative treatment for many parasite diseases. In a previous paper, we communicated about the antiprotozoal activity in vitro of the methanolic (MeOH) extract of Ruta chalepensis (Rutaceae) against E. histolytica. The plant is extensively employed in Mexican traditional medicine. The following workup of the MeOH extract of R. chalepensis afforded the furocoumarins rutamarin (1) and chalepin (2), which showed high antiprotozoal activity on Entamoeba histolytica trophozoites employing in vitro tests (IC50 values of 6.52 and 28.95 µg/mL, respectively). Therefore, we offer a full scientific report about the bioguided isolation and the amebicide activity of chalepin and rutamarin.
Assuntos
Furocumarinas/isolamento & purificação , Ruta/metabolismo , Amebicidas/isolamento & purificação , Amebicidas/farmacologia , Antiprotozoários/farmacologia , Benzopiranos/metabolismo , Entamoeba histolytica/efeitos dos fármacos , Entamoeba histolytica/patogenicidade , Furocumarinas/farmacologia , Concentração Inibidora 50 , Medicina Tradicional , México , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologiaRESUMO
Indazole is an important scaffold in medicinal chemistry. At present, the progress on synthetic methodologies has allowed the preparation of several new indazole derivatives with interesting pharmacological properties. Particularly, the antiprotozoal activity of indazole derivatives have been recently reported. Herein, a series of 22 indazole derivatives was synthesized and studied as antiprotozoals. The 2-phenyl-2H-indazole scaffold was accessed by a one-pot procedure, which includes a combination of ultrasound synthesis under neat conditions as well as Cadogan's cyclization. Moreover, some compounds were derivatized to have an appropriate set to provide structure-activity relationships (SAR) information. Whereas the antiprotozoal activity of six of these compounds against E. histolytica, G. intestinalis, and T. vaginalis had been previously reported, the activity of the additional 16 compounds was evaluated against these same protozoa. The biological assays revealed structural features that favor the antiprotozoal activity against the three protozoans tested, e.g., electron withdrawing groups at the 2-phenyl ring. It is important to mention that the indazole derivatives possess strong antiprotozoal activity and are also characterized by a continuous SAR.
Assuntos
Antiprotozoários/síntese química , Antiprotozoários/farmacologia , Quimioinformática , Indazóis/síntese química , Indazóis/farmacologia , Antiprotozoários/química , Entamoeba histolytica/efeitos dos fármacos , Giardia lamblia/efeitos dos fármacos , Indazóis/química , Concentração Inibidora 50 , Testes de Sensibilidade Parasitária , Relação Estrutura-Atividade , Trichomonas vaginalis/efeitos dos fármacos , UltrassomRESUMO
Currently, there is growing interest in the identification and purification of microbial lectins due to their involvement in the pathogenicity mechanisms of pathogens, such as Entamoeba histolytica and free-living amoebae. The Gal/GalNAc lectin from E. histolytica participates in adhesion, cytotoxicity and regulation of immune responses. Furthermore, mannose- and galactose-binding protein have been described in Acanthamoeba castellanii and Balamuthia mandrillaris, respectively and they also contribute to host damage. Finally, in Naegleria fowleri, molecules containing mannose and fucose are implicated in adhesion and cytotoxicity. Considering their relevance in the pathogenesis of the diseases caused by these protozoa, lectins appear to be promising targets in the diagnosis, vaccination and treatment of these infections.
Assuntos
Amoeba/efeitos dos fármacos , Entamoeba histolytica/efeitos dos fármacos , Lectinas/farmacologia , Fatores de Virulência , Amebíase/diagnóstico , Animais , Balamuthia mandrillaris , Entamebíase/diagnóstico , Entamebíase/tratamento farmacológico , Entamebíase/parasitologia , Glicoconjugados , Glicoproteínas , Interações Hospedeiro-Parasita , Humanos , Naegleria fowleri , VacinaçãoRESUMO
Amebiasis caused by Entamoeba histolytica is nowadays a serious public health problem worldwide, especially in developing countries. Annually, up to 100,000 deaths occur across the world. Due to the resistance that pathogenic protozoa exhibit against commercial antiprotozoal drugs, a growing emphasis has been placed on plants used in traditional medicine to discover new antiparasitics. Previously, we reported the in vitro antiamoebic activity of a methanolic extract of Lippia graveolens Kunth (Mexican oregano). In this study, we outline the isolation and structure elucidation of antiamoebic compounds occurring in this plant. The subsequent work-up of this methanol extract by bioguided isolation using several chromatographic techniques yielded the flavonoids pinocembrin (1), sakuranetin (2), cirsimaritin (3), and naringenin (4). Structural elucidation of the isolated compounds was achieved by spectroscopic/spectrometric analyses and comparing literature data. These compounds revealed significant antiprotozoal activity against E. histolytica trophozoites using in vitro tests, showing a 50% inhibitory concentration (IC50) ranging from 28 to 154 µg/mL. Amebicide activity of sakuranetin and cirsimaritin is reported for the first time in this study. These research data may help to corroborate the use of this plant in traditional Mexican medicine for the treatment of dyspepsia.
Assuntos
Antiprotozoários/química , Antiprotozoários/farmacologia , Entamoeba histolytica/efeitos dos fármacos , Flavonoides/química , Flavonoides/farmacologia , Lippia/química , Doenças Transmissíveis/parasitologia , Flavanonas/química , Flavanonas/farmacologia , Flavonas/química , Flavonas/farmacologiaRESUMO
In this work, we present the synthesis, characterization, electrochemical studies, DFT calculations, and in vitro amoebicidal effect of seven new heteroleptic NiII coordination compounds. The crystal structures of [H2(pdto)](NO3)2 and [Ni(pdto)(NO3)]PF6 are presented, pdtoâ¯=â¯2,2'-[1,2-ethanediylbis-(sulfanediyl-2,1-ethanediyl)]dipyridine. The rest of the compounds have general formulae: [Ni(pdto)(NN)](PF6) where N-Nâ¯=â¯2,2'-bipyridine (bpy), 4,4'-dimethyl-2,2'-bipyridine (44dmbpy), 5,5'-dimethyl-2,2'-bipyridine (55dmbpy), 1,10-phenanthroline (phen), 4,7-dimethyl-1,10-phenanthroline (47dmphen) and 5,6-dimethyl-1,10-phenanthroline (56dmphen). The size of NN ligand and its substituents modulate the compound electronic features and influence their antiproliferative efficiency against Entamoeba histolytica. 56dmphen derivative, shows the biggest molar volume and presents a powerful amoebicidal activity (IC50â¯=â¯1.2⯵M), being seven times more effective than the first-line drug for human amoebiasis metronidazole. Also, increases the reactive oxygen species concentration within the trophozoites. This could be the trigger of the E. histolytica growth inhibition. The antiparasitic effect is described using NiII electron density, molar volume, estimated by DFT, as well as the experimental redox potential and diffusion coefficients. In general, amoebicidal efficiency is directly proportional to the increment of the molar volume and decreases when the redox potential becomes more positive.
Assuntos
Amebicidas/farmacologia , Complexos de Coordenação/farmacologia , Entamoeba histolytica/crescimento & desenvolvimento , Níquel/química , Compostos Organometálicos/farmacologia , Amebicidas/química , Animais , Complexos de Coordenação/química , Cristalografia por Raios X , Entamoeba histolytica/efeitos dos fármacos , Modelos Moleculares , Compostos Organometálicos/químicaRESUMO
Herein is presented the synthesis, characterization, electrochemical studies, DFT calculations and in vitro evaluation of amoebicidal activity in trophozoites of Entamoeba histolytica of twenty ruthenium (II) mixed compounds with general formulae: [Ru(pdto)(E-E)]Clx (E-E bidentate, either neutral or negatively charged ligands). For compounds under study, O-O, N-O and N-N auxiliary donor ligands demonstrate to have a crucial impact on the electronic properties and that it is possible to modulate the antiparasitic activity. Among analyzed complexes, only four present a better performance compared to typically used metronidazole drug (IC50 < 6.80 µmol/L) to treat amebiasis disease. For studied compounds, structure-activity relationships are strongly determined by either the redox potential (E1/2) of RuII/RuIII and calculated molar volume (V) of the complexes.
Assuntos
Antiparasitários/farmacologia , Entamoeba histolytica/efeitos dos fármacos , Entamebíase/tratamento farmacológico , Compostos Organometálicos/farmacologia , Rutênio/química , Antiparasitários/química , Eletroquímica , Entamebíase/parasitologia , Compostos Organometálicos/química , Relação Estrutura-AtividadeRESUMO
Amoebiasis is caused by the protozoan Entamoeba histolytica that affects millions of people throughout the world. The standard treatment is metronidazole, however, this drug causes several side effects, and is also mutagenic and carcinogenic. Therefore, the search for therapeutic alternatives is necessary. Quinoxaline 1,4-di-N-oxides (QdNOs) derivatives have been shown to exhibit activity against different protozoan. In the present study, the effects of esters of quinoxaline-7-carboxylate 1,4-di-N-oxide (7-carboxylate QdNOs) derivatives on E. histolytica proliferation, morphology, ultrastructure, and oxidative stress were evaluated, also their potential as E. histolytica thioredoxin reductase (EhTrxR) inhibitors was analyzed. In vitro tests showed that 12 compounds from n-propyl and isopropyl series, were more active (IC50 = 0.331 to 3.56 µM) than metronidazole (IC50 = 4.5 µM). The compounds with better biological activity have a bulky, trifluoromethyl and isopropyl group at R1-, R2-, and R3-position, respectively. The main alterations found in trophozoites treated with some of these compounds included changes in chromatin, cell granularity, redistribution of vacuoles with cellular debris, and an increase in reactive oxygen species. Interestingly, docking studies suggested that 7-carboxylate QdNOs derivatives could interact with amino acid residues of the NADPH-binding domain and/or the redox-active site of EhTrxR. Enzymatic assays demonstrated that selected 7-carboxylate QdNOs inhibits EhTrxR disulfide reductase activity, and diaphorase activity shows that these compounds could act as electron acceptor substrates for the enzyme. Taken together, these data indicate that among the mechanisms involved in the antiamoebic effect of the 7-carboxylate QdNOs derivatives studied, is the induction of oxidative stress and the inhibition of EhTrxR activity.
Assuntos
Entamoeba histolytica/efeitos dos fármacos , Quinoxalinas/farmacologia , Tiorredoxina Dissulfeto Redutase/antagonistas & inibidores , Óxidos N-Cíclicos , Entamoeba histolytica/enzimologia , Ésteres , Humanos , Metronidazol/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Quinolinas , Espécies Reativas de Oxigênio/metabolismoRESUMO
Amoebiasis is a parasitic disease that causes thousands of deaths every year, its adverse effects and resistance to conventional treatments have led to the search of new treatment options, as well as the development of novel screening methods. In this work, we implemented a 3D model of intestine and liver slices from hamsters that were infected ex vivo with virulent E. histolytica trophozoites. Results show preserved histology in both uninfected tissues as well as ulcerations, destruction of the epithelial cells, and inflammatory reaction in intestine slices and formation of micro abscesses, and the presence of amoebae in the sinusoidal spaces and in the interior of central veins in liver slices. The three chemically synthetized compounds T-001, T-011, and T-016, which act as amoebicides in vitro, were active in both infected tissues, as they decreased the number of trophozoites, and provoked death by disintegration of the amoeba, similar to metronidazole. However, compound T-011 induced signs of cytotoxicity to liver slices. Our results suggest that ex vivo cultures of precision-cut intestinal and liver slices represent a reliable 3D approach to evaluate novel amoebicidal compounds, and to simultaneously detect their toxicity, while reducing the number of experimental animals commonly required by other model systems.
Assuntos
Amebicidas/farmacologia , Avaliação Pré-Clínica de Medicamentos , Entamoeba histolytica/efeitos dos fármacos , Fígado/parasitologia , Modelos Moleculares , Animais , Morte Celular/efeitos dos fármacos , Cricetinae , Entamebíase/parasitologia , Entamebíase/patologia , Intestinos/parasitologia , MasculinoRESUMO
Oxygen or nitrogen oxidative species and chemical stress induce the programmed cell death (PCD) of Entamoeba histolytica trophozoites. PCD caused by the aminoglycoside G418 is reduced by incubation with the cysteine protease inhibitor E-64; however, no typical caspases or metacaspases have been detected in this parasite. Calpain, a cysteine protease activated by calcium, has been suggested to be part of a specific PCD pathway in this parasite because the specific calpain inhibitor Z-Leu-Leu-Leu-al diminishes the PCD of trophozoites. Here, we predicted the hypothetical 3D structure of a calpain-like protein of E. histolytica and produced specific antibodies against it. We detected the protein in the cytoplasm and near the nucleus. Its expression gradually increased during incubation with G418, with the highest level after 9 h of treatment. In addition, a specific calpain-like siRNA sequence reduced the cell death rate by 65%. All these results support the hypothesis that the calpain-like protein is one of the proteases involved in the execution phase of PCD in E. histolytica. The hypothetical interactome of the calpain-like protein suggests that it may activate or regulate other proteins that probably participate in PCD, including those with EF-hand domains or other calcium-binding sites.
Assuntos
Apoptose , Calpaína/metabolismo , Entamoeba histolytica/fisiologia , Calpaína/antagonistas & inibidores , Biologia Computacional , Entamoeba histolytica/efeitos dos fármacos , Ativadores de Enzimas/metabolismo , Gentamicinas/metabolismo , Mapas de Interação de ProteínasRESUMO
Entamoeba histolytica, the causal agent of human amoebiasis, has two morphologically different phases: a resistant cyst and a trophozoite responsible for the invasion of the host tissues such as the colonic mucosa and the intestinal epithelium. During in vitro migration, trophozoites usually produce protuberances such as pseudopods and rarely filopodia, structures that have been observed in the interaction of trophozoites with human colonic epithelial tissue. To study the different membrane projections produced by the trophozoites, including pseudopods, filopodia, uropods, blebs, and others, we designed an induction system using erythrocyte extract or fibronectin (FN) in micropatterned grill lines (each micro-line containing multiple micro-portions of FN or erythrocyte extract) on which the trophozoites were placed in culture for migration assays. Using light, confocal, and scanning electron microscopy, we established that E. histolytica trophozoites frequently produce short and long filopodia, large retractile uropods in the rear, pseudopods, blebs, and others structures, also showing continuous migration periods. The present study provides a simple migration method to induce trophozoites to generate abundant membrane protrusion structures that are rarely obtained in normal or induced cultures, such as long filopodia; this method will allow a-better understanding of the interactions of trophozoites with FN and cell debris. E. histolytica trophozoites motility plays an important role in invasive amoebiasis. It has been proposed that both physical forces and chemical signals are involved in the trophozoite motility and migration. However, the in vivo molecules that drive the chemotactic migration remain to be determined. We propose the present assay to study host molecules that guide chemotactic behavior because the method is highly reproducible, and a live image of cell movement and migration can be quantified.
Assuntos
Movimento Celular , Extensões da Superfície Celular/fisiologia , Extensões da Superfície Celular/ultraestrutura , Entamoeba histolytica/fisiologia , Entamoeba histolytica/ultraestrutura , Trofozoítos/fisiologia , Trofozoítos/ultraestrutura , Extratos Celulares/isolamento & purificação , Extensões da Superfície Celular/efeitos dos fármacos , Entamoeba histolytica/efeitos dos fármacos , Eritrócitos/química , Fibronectinas/isolamento & purificação , Fibronectinas/metabolismo , Humanos , Microscopia , Microscopia Confocal , Microscopia Eletrônica de Varredura , Trofozoítos/efeitos dos fármacosRESUMO
Over the past 20 years, gastrointestinal infections in developing countries have been a serious health problem and are the second leading cause of morbidity among all age groups. Among pathogenic protozoans that cause diarrheal disease, the parasite Entamoeba histolytica produces amebic colitis as well as the most frequent extra-intestinal lesion, an amebic liver abscess (ALA). Usually, intestinal amebiasis and ALA are treated with synthetic chemical compounds (iodoquinol, paromomycin, diloxanide furoate, and nitroimidazoles). Metronidazole is the most common treatment for amebiasis. Although the efficacy of nitroimidazoles in killing amebas is known, the potential resistance of E. histolytica to this treatment is a concern. In addition, controversial studies have reported that metronidazole could induce mutagenic effects and cerebral toxicity. Therefore, natural and safe alternative drugs against this parasite are needed. Flavonoids are natural polyphenolic compounds. Flavonoids depend on malonyl-CoA and phenylalanine to be synthesized. Several flavonoids have anti-oxidant and anti-microbial properties. Since the 1990s, several works have focused on the identification and purification of different flavonoids with amebicidal effects, such as, -(-)epicatechin, kaempferol, and quercetin. In this review, we investigated the effects of flavonoids that have potential amebicidal activity and that can be used as complementary and/or specific therapeutic strategies against E. histolytica trophozoites. Interestingly, it was found that these natural compounds can induce morphological changes in the amebas, such as chromatin condensation and cytoskeletal protein re-organization, as well as the upregulation and downregulation of fructose-1,6-bisphosphate aldolase, glyceraldehyde-phosphate dehydrogenase, and pyruvate:ferredoxin oxidoreductase (enzymes of the glycolytic pathway). Although the specific molecular targets, bioavailability, route of administration, and doses of some of these natural compounds need to be determined, flavonoids represent a very promising and innocuous strategy that should be considered for use against E. histolytica in the era of microbial drug resistance.
Assuntos
Antiprotozoários/administração & dosagem , Antiprotozoários/farmacologia , Entamoeba histolytica/efeitos dos fármacos , Entamebíase/tratamento farmacológico , Flavonoides/administração & dosagem , Flavonoides/farmacologia , HumanosRESUMO
Messenger RNA 3'-end polyadenylation is an important regulator of gene expression in eukaryotic cells. In our search for new ways of treating parasitic infectious diseases, we looked at whether or not alterations in polyadenylation might control the survival of Entamoeba histolytica (the agent of amoebiasis in humans). We used molecular biology and computational tools to characterize the mRNA cleavage factor EhCFIm25, which is essential for polyadenylation in E. histolytica. By using a strategy based on the systematic evolution of ligands by exponential enrichment, we identified single-stranded RNA aptamers that target EhCFIm25. The results of RNA-protein binding assays showed that EhCFIm25 binds to the GUUG motif in vitro, which differs from the UGUA motif bound by the homologous human protein. Accordingly, docking experiments and molecular dynamic simulations confirmed that interaction with GUUG stabilizes EhCFIm25. Incubating E. histolytica trophozoites with selected aptamers inhibited parasite proliferation and rapidly led to cell death. Overall, our data indicate that targeting EhCFIm25 is an effective way of limiting the growth of E. histolytica in vitro. The present study is the first to have highlighted the potential value of RNA aptamers for controlling this human pathogen.
Assuntos
Antiprotozoários/farmacologia , Aptâmeros de Nucleotídeos/farmacologia , Entamoeba histolytica/crescimento & desenvolvimento , Fatores de Poliadenilação e Clivagem de mRNA/antagonistas & inibidores , Fatores de Poliadenilação e Clivagem de mRNA/química , Motivos de Aminoácidos , Antiprotozoários/química , Aptâmeros de Nucleotídeos/química , Sítios de Ligação , Biologia Computacional/métodos , Entamoeba histolytica/efeitos dos fármacos , Entamoeba histolytica/metabolismo , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Ligação Proteica , Proteínas de Protozoários/antagonistas & inibidores , Proteínas de Protozoários/química , RNA/farmacologia , Técnica de Seleção de Aptâmeros , Trofozoítos/efeitos dos fármacos , Trofozoítos/crescimento & desenvolvimento , Trofozoítos/metabolismoRESUMO
OBJECTIVES: This study was undertaken to investigate the amoebicidal potential of curcumin on Entamoeba histolytica, as well as its synergistic effect with metronidazole. METHODS: Entamoeba histolytica trophozoites were exposed to 100, 200 and 300 µm of curcumin, for 6, 12 and 24 h. Consequently, the viability of cells was determined by trypan blue exclusion test. All specimens were further analysed by scanning electron microscopy. For drug combination experiment, the Chou-Talalay method was used. KEY FINDINGS: Curcumin affected the growth and cell viability in a time- and dose-dependent manner. The higher inhibitory effects were observed with 300 µm at 24 h; 65.5% of growth inhibition and only 28.8% of trophozoites were viable. Additionally, curcumin also altered adhesion and the morphology of the trophozoites. Scanning electron microscopy revealed treated trophozoites with damages on the membrane, size alterations and parasites with loss of cellular integrity. In addition, the combination of curcumin + metronidazole exhibited a synergistic effect; the activity of both drugs was improved. CONCLUSIONS: This is the first report evaluating the effectiveness of curcumin against E. histolytica. Our results suggest that CUR could be considered for evaluation in future pharmacological studies as a promising amoebicidal agent or as complementary therapy.
Assuntos
Curcumina/farmacologia , Entamoeba histolytica/efeitos dos fármacos , Entamoeba histolytica/crescimento & desenvolvimento , Trofozoítos/efeitos dos fármacos , Animais , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Metronidazol/farmacologia , Testes de Sensibilidade Parasitária , Trofozoítos/crescimento & desenvolvimento , Trofozoítos/ultraestruturaRESUMO
Transcriptional regulation of the multidrug resistance EhPgp5 gene in Entamoeba histolytica is induced by emetine stress. EhPgp5 overexpression alters the chloride-dependent currents that cause trophozoite swelling, diminishing induced programmed cell death (PCD) susceptibility. In contrast, antisense inhibition of P-glycoprotein (PGP) expression produces synchronous death of trophozoites and the enhancement of the biochemical and morphological characteristics of PCD induced by G418. Transcriptional gene regulation analysis identified a 59 bp region at position -170 to -111 bp promoter as putative emetine response elements (EREs). However, insights into transcription factors controlling EhPgp5 gene transcription are missing; to fill this knowledge gap, we used deletion studies and transient CAT activity assays. Our findings suggested an activating motif (-151 to -136 bp) that corresponds to a heat shock element (HSE). Gel-shift assays, UV-crosslinking, binding protein purification, and western blotting assays revealed proteins of 94, 66, 62, and 51 kDa binding to the EhPgp5 HSE that could be heat shock-like transcription factors that regulate the transcriptional activation of the EhPgp5 gene in the presence of emetine drug.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Emetina/farmacologia , Entamoeba histolytica/efeitos dos fármacos , Entamoeba histolytica/metabolismo , Resposta ao Choque Térmico/fisiologia , Proteínas de Protozoários/genética , Ativação Transcricional/fisiologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Sequência de Bases , Sítios de Ligação , Resistência a Múltiplos Medicamentos/genética , Eletroporação , Entamoeba histolytica/genética , Entamoeba histolytica/crescimento & desenvolvimento , Regulação da Expressão Gênica/efeitos dos fármacos , Genes de Protozoários/efeitos dos fármacos , Regiões Promotoras Genéticas/efeitos dos fármacos , Regiões Promotoras Genéticas/fisiologia , Proteínas de Protozoários/análise , Proteínas de Protozoários/fisiologia , Fatores de Transcrição/metabolismo , Transcrição Gênica , Transfecção , Trofozoítos/efeitos dos fármacosRESUMO
Indazole is considered a very important scaffold in medicinal chemistry. It is commonly found in compounds with diverse biological activities, e.g., antimicrobial and anti-inflammatory agents. Considering that infectious diseases are associated to an inflammatory response, we designed a set of 2H-indazole derivatives by hybridization of cyclic systems commonly found in antimicrobial and anti-inflammatory compounds. The derivatives were synthesized and tested against selected intestinal and vaginal pathogens, including the protozoa Giardia intestinalis, Entamoeba histolytica, and Trichomonas vaginalis; the bacteria Escherichia coli and Salmonella enterica serovar Typhi; and the yeasts Candida albicans and Candida glabrata. Biological evaluations revealed that synthesized compounds have antiprotozoal activity and, in most cases, are more potent than the reference drug metronidazole, e.g., compound 18 is 12.8 times more active than metronidazole against G. intestinalis. Furthermore, two 2,3-diphenyl-2H-indazole derivatives (18 and 23) showed in vitro growth inhibition against Candida albicans and Candida glabrata. In addition to their antimicrobial activity, the anti-inflammatory potential for selected compounds was evaluated in silico and in vitro against human cyclooxygenase-2 (COX-2). The results showed that compounds 18, 21, 23, and 26 display in vitro inhibitory activity against COX-2, whereas docking calculations suggest a similar binding mode as compared to rofecoxib, the crystallographic reference.
Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Indazóis/química , Anti-Infecciosos/síntese química , Anti-Inflamatórios não Esteroides/síntese química , Antiprotozoários/síntese química , Antiprotozoários/química , Antiprotozoários/farmacologia , Técnicas de Química Sintética , Simulação por Computador , Ciclo-Oxigenase 2/química , Ciclo-Oxigenase 2/metabolismo , Inibidores de Ciclo-Oxigenase 2/química , Inibidores de Ciclo-Oxigenase 2/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Entamoeba histolytica/efeitos dos fármacos , Giardia lamblia/efeitos dos fármacos , Células HeLa , Humanos , Indazóis/síntese química , Simulação de Acoplamento Molecular , Trichomonas vaginalis/efeitos dos fármacosRESUMO
A series of twelve new 2-(methylthio)-1H-benzimidazole-5-carboxamide derivatives (1-12) were synthesized and their antiparasitic activity was tested in vitro against Giardia intestinalis, Trichomonas vaginalis and Entamoeba histolytica. Experimental evaluations showed IC50 values within the nanomolar range for all tested compounds, some showing higher activity than metronidazole and albendazole. A chemoinformatic study was used to compare the structure-activity relationship of the synthesized carboxamides with those of 91 previously studied benzimidazoles, and with some Nitazoxanide-N-methylbenzimidazole hybrids recently synthetized by our group. Compounds 1 and 3 were identified as prominent selective compounds against T. vaginalis and G. intestinalis, respectively, while compound 4 was found to be of broad spectrum against the three protozoans.
Assuntos
Antiprotozoários/farmacologia , Benzimidazóis/farmacologia , Entamoeba histolytica/efeitos dos fármacos , Giardia lamblia/efeitos dos fármacos , Trichomonas vaginalis/efeitos dos fármacos , Antiprotozoários/síntese química , Antiprotozoários/química , Benzimidazóis/síntese química , Benzimidazóis/química , Relação Dose-Resposta a Droga , Estrutura Molecular , Testes de Sensibilidade Parasitária , Relação Estrutura-AtividadeRESUMO
Petiveria alliacea L. (Phytolacaceae) is a medicinal plant with a broad range of traditional therapeutic properties, including the treatment of dysentery and intestinal infections caused by protozoan parasites. However, its effects against Entamoeba histolytica have not been reported yet. We investigated the antiamoebic activity present in the leaves of P. alliacea Antiamoebic activity was evaluated in methanolic and aqueous extracts, as well as in the hexanic, methanolic, and EtOAc fractions. The P. alliacea methanolic extract showed a better antiamoebic activity than the aqueous extract with an IC50 = 0.51 mg/ml. Likewise, the hexanic fraction was the most effective fraction, showing a dose-dependent activity against E. histolytica, with an IC50 = 0.68 mg/ml. Hexanic subfraction 12-19 showed the highest antiamoebic activity at 0.8 mg/ml, producing 74.3% growth inhibition without any toxicity in mammal cells. A major component in subfraction 12-19 was identified as isoarborinol, which produced 51.4% E. histolytica growth inhibition at 0.05 mg/ml without affecting mammal cells. The P. alliacea leaf extract has antiamoebic activity that can be attributed to a major metabolite known as isoarborinol.
Assuntos
Antiprotozoários/farmacologia , Entamoeba histolytica/efeitos dos fármacos , Compostos Fitoquímicos/farmacologia , Phytolaccaceae/química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Triterpenos/farmacologia , Antiprotozoários/isolamento & purificação , Concentração Inibidora 50 , Testes de Sensibilidade Parasitária , Compostos Fitoquímicos/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Triterpenos/isolamento & purificaçãoRESUMO
Cnidoscolus chayamansa is a medicinal and edible plant known as Chaya, is commonly used as an anti-inflammatory, antiprotozoal, antibacterial agent and as a remedy for respiratory illness, gastrointestinal disorders, and vaginal infections related with the inflammation process. In this paper, we describe the plant's phytochemical analysis and biological activities (antimycobacterial, antibacterial, antiprotozoal, and anti-inflammatory properties) of the CHCl3:MeOH (1:1) leaves extract and isolated compounds, as well as the acute and sub-acute toxic effects. Chemical identification of isolated compounds was performed by 1H- and 13C NMR spectra data. In vitro antibacterial and antimycobacterial activities were determined by disc diffusion and MABA assays, respectively; antiprotozoal test by means of the sub-culture test. Topical and systemic anti-inflammatory effects were tested by TPA and carrageenan assay on BALB/c mice. Moretenol, moretenyl acetate, kaempferol-3,7-dimethyl ether, and 5-hydroxy-7-3',4'-trimethoxyflavanone were the main compounds isolated. The CHCl3:MeOH extract showed antiprotozoal (IC50≤65.29µg/mL), antimycobacterial (MIC≤50µg/mL), and anti-inflammatory activities (ED50=1.66mg/ear and 467.73mg/kg), but was inactive against the bacterial strains tested. The LD50 for extract was >2g/kg. In the sub-acute toxicity test, the extract was administered at 1g/kg for 28days and did not cause lethality or any alteration in hematological and biochemical parameters; in addition, liver, kidney, and spleen histological analysis exhibited no structural changes. Moretenol and moretenyl acetate showed MIC=25µg/mL against Mycobacterium tuberculosis H37Rv and against four monoresistant strains of M. tuberculosis H37Rv. Both compounds exhibited moderate activity against Entamoeba histolytica and Giardia lamblia (IC50≤71.70µg/mL). Kaempferol-3,7-dimethyl ether and 5-hydroxy-7-3',4'-trimethoxy-flavanone were more active than the extract against E. histolytica and G. lamblia, showing IC50 ≤27.43µg/mL. As topical anti-inflammatory agents, moretenol and kaempferol-3,7-dimethyl ether were the most active compounds inhibiting the edema in 30.52 and 26.67%, respectively. Moretenol and moretenyl acetate showed significant antimycobacterial and antiprotozoal activities; in addition, important antiprotozoal effect was detected with kaempferol-3,7-dimethyl ether and 5-hydroxy-7-3',4'-trimethoxyflavanone. The extract and the terpenoids possess good anti-inflammatory activity. The extract did not produce lethality or adverse effects in acute and sub-acute tests.
Assuntos
Antibacterianos/farmacologia , Anti-Inflamatórios não Esteroides/farmacologia , Antiprotozoários/farmacologia , Antituberculosos/farmacologia , Euphorbiaceae/química , Extratos Vegetais/farmacologia , Animais , Farmacorresistência Bacteriana/efeitos dos fármacos , Entamoeba histolytica/efeitos dos fármacos , Euphorbiaceae/toxicidade , Giardia lamblia/efeitos dos fármacos , Inflamação/induzido quimicamente , Inflamação/prevenção & controle , Dose Letal Mediana , Masculino , México , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/efeitos dos fármacos , Extratos Vegetais/química , Extratos Vegetais/toxicidadeRESUMO
Three water-soluble Ru(II) chiral heteroleptic coordination compounds [Ru(en)(pdto)]Cl2 (1), [Ru(gly)(pdto)]Cl (2), and [Ru(acac)(pdto)]Cl (3), where pdto = 2,2'-[1,2-ethanediylbis-(sulfanediyl-2,1-ethanediyl)]dipyridine, en = ethylendiamine, gly = glycinate, and acac = acetylacetonate, have been synthezised and fully characterized. The crystal structures of compounds 1-3 are described. The IC50 values for compounds 1-3 are within nanomolar range (14, 12, and 6 nM, respectively). The cytotoxicity for human peripheral blood lymphocytes is extremely low (>100 µM). Selectivity indexes for Ru(II) compounds are in the range 700-1300. Trophozoites exposed to Ru(II) compounds die through an apoptotic pathway triggered by ROS production. The orally administration to infected mice induces a total elimination of the parasite charge in mice faeces 1-2-fold faster than metronidazole. Besides, all compounds inhibit the trophozoite proliferation in amoebic liver abscess induced in hamster. All our results lead us to propose these compounds as promising candidates as antiparasitic agents.
Assuntos
Antiprotozoários/farmacologia , Entamoeba histolytica/efeitos dos fármacos , Compostos de Rutênio/farmacologia , Animais , Antiprotozoários/química , Antiprotozoários/uso terapêutico , Apoptose/efeitos dos fármacos , Células Cultivadas , Cricetinae , Cristalografia por Raios X , Humanos , Concentração Inibidora 50 , Abscesso Hepático Amebiano/tratamento farmacológico , Camundongos , Espécies Reativas de Oxigênio/metabolismo , Compostos de Rutênio/química , Compostos de Rutênio/uso terapêutico , EstereoisomerismoRESUMO
BACKGROUND: Chagas disease, amebiasis, giardiasis and trichomoniasis represent a serious health problem in Latin America. The drugs employed to treat these illnesses produce important side effects and resistant strains have appeared. The present study was aimed to evaluate the antiprotozoal activity of leaves, stem bark and root bark of Elaeodendron trichotomum, a celastraceus, that is used in Mexico as an anti-infective in febrile-type diseases. MATERIALS AND METHODS: Dichloromethane and methanol extracts of leaves, bark and roots of Elaeodendron trichotomum were tested against Entamoeba histolytica, Giardia lamblia, Trichomonas vaginalis, and Trypanosoma cruzi. A quantitative HPLC analysis of pristimerin and tingenone was performed. RESULTS: The dichloromethane extract of roots was active against E. histolytica, G. lamblia, T. vaginalis, and T. cruzi, at IC50's of 0.80, 0.44, 0.46, and 2.68 µg/mL, respectively. The HPLC analysis revealed the presence of tingenone (3.84%) and pristimerin (0.14%). CONCLUSIONS: The dichloromethane extract of the roots bark showed significant activity against all screened protozoa.