RESUMO
In this study, we present the design, synthesis, and cytotoxic evaluation of a series of benzimidazole N-acylhydrazones against strains of T. cruzi (Y and Tulahuen) and Leishmania species (L. amazonensis and L. infantum). Compound (E)-N'-((5-Nitrofuran-2-yl)methylene)-1H-benzo[d]imidazole-2-carbohydrazide demonstrated significant activity against both trypomastigote and amastigote forms (Tulahuen strain), with an IC50/120 h of 0.033 µM and a selectivity index (SI) of 7680. This represents a potency 46 times greater than that of benznidazole (IC50/120 h = 1.520 µM, SI = 1390). Another compound (E)-N'-(2-Hydroxybenzylidene)-1H-benzo[d]imidazole-2-carbohydrazide showed promising activity against both trypomastigote and amastigote forms (Tulahuen strain), with an IC50/120 h of 3.600 µM and an SI of 14.70. However, its efficacy against L. infantum and L. amazonensis was comparatively lower. These findings provide valuable insights for the development of more effective treatments against Trypanosoma cruzi.
Assuntos
Benzimidazóis , Hidrazonas , Leishmania infantum , Trypanosoma cruzi , Trypanosoma cruzi/efeitos dos fármacos , Hidrazonas/farmacologia , Hidrazonas/química , Hidrazonas/síntese química , Relação Estrutura-Atividade , Leishmania infantum/efeitos dos fármacos , Benzimidazóis/farmacologia , Benzimidazóis/química , Benzimidazóis/síntese química , Estrutura Molecular , Testes de Sensibilidade Parasitária , Relação Dose-Resposta a Droga , Leishmania/efeitos dos fármacos , Tripanossomicidas/farmacologia , Tripanossomicidas/síntese química , Tripanossomicidas/química , Antiprotozoários/farmacologia , Antiprotozoários/síntese química , Antiprotozoários/química , AnimaisRESUMO
Aim: To synthesize novel more potent trypanocidal and leishmanicidal agents. Methods: Hantzsch's synthetic strategy was used to synthesize 1,3-thiazole-4-carboxylates and their N-benzylated derivatives. Results: 28 new thiazole-carboxylates and their N-benzylated derivatives were established to test their trypanocidal and leishmanicidal activities. From both series, compounds 3b, 4f, 4g, 4j and 4n exhibited a better or comparable trypanocidal profile to benznidazole. Among all tested compounds, 4n was found to be the most potent and was better than benznidazole. Conclusion: Further variation of substituents around 1,3-thiazole-4-carboxylates and or hydrazinyl moiety may assist in establishing better and more potent trypanocidal and leishmanicidal agents.
Chagas disease and leishmaniasis are neglected tropical diseases. Herein, 28 1,3-thiazoles have been synthesized from thiosemicarbazones in a rapid, efficient and cost-effective manner. In vitro assays were performed against intracellular amastigotes of Trypanosoma cruzi (T. cruzi) and promastigotes and intracellular amastigote forms of Leishmania infantum (L. infantum) and Leishmania amazonensis (L. amazonensis). Some of the 1,3-thiazole-4-carboxylates inhibited the amastigote form of T. cruzi without affecting macrophage viability, compound 4n being the most potent and better than benznidazole. Our synthesized compounds exhibited promising activity against T. cruzi, thus broadening options for scaffold and lead compound optimization. Concerning the leishmanicidal activity, compound 4g was the best prototype in terms of potency and selectivity. Compounds 4g and 3m showed moderate selectivity and potency against intracellular amastigotes of L. amazonensis and L. infantum, respectively.
Assuntos
Nitroimidazóis , Tripanossomicidas , Trypanosoma cruzi , Tiazóis/farmacologia , Ésteres/farmacologia , Tripanossomicidas/farmacologiaRESUMO
Writing and erasing of posttranslational modifications are crucial to phenotypic plasticity and antigenic variation of eukaryotic pathogens. Targeting pathogens' modification machineries, thus, represents a valid approach to fighting parasitic diseases. However, identification of parasitic targets and the development of selective anti-parasitic drugs still represent major bottlenecks. Here, we show that the zinc-dependent histone deacetylases (HDACs) of the protozoan parasite Trypanosoma cruzi are key regulators that have significantly diverged from their human counterparts. Depletion of T. cruzi class I HDACs tcDAC1 and tcDAC2 compromises cell-cycle progression and division, leading to cell death. Notably, tcDAC2 displays a deacetylase activity essential to the parasite and shows major structural differences with human HDACs. Specifically, tcDAC2 harbors a modular active site with a unique subpocket targeted by inhibitors showing substantial anti-parasitic effects in cellulo and in vivo. Thus, the targeting of the many atypical HDACs in pathogens can enable anti-parasitic selective chemical impairment.
Assuntos
Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/genética , Histona Desacetilases/metabolismo , Trypanosoma cruzi/enzimologia , Trypanosoma cruzi/genética , Trypanosoma cruzi/metabolismo , Animais , Domínio Catalítico , Ciclo Celular , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Chlorocebus aethiops , DNA de Protozoário , Feminino , Teste de Complementação Genética , Inibidores de Histona Desacetilases/química , Histona Desacetilases/química , Interações Hospedeiro-Parasita , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Modelos Moleculares , Filogenia , Conformação Proteica , Processamento de Proteína Pós-Traducional , Proteínas de Protozoários/química , Proteínas de Protozoários/metabolismo , Deleção de Sequência , Trypanosoma cruzi/efeitos dos fármacos , Células VeroRESUMO
BACKGROUND: Chagas disease, also known as American trypanosomiasis, is classified as one of the 17 most important neglected diseases by the World Health Organization. The only drugs with proven efficacy against Chagas disease are benznidazole and nifurtimox, however both show adverse effects, poor clinical efficacy, and development of resistance. For these reasons, the search for new effective chemical entities is a challenge to research groups and the pharmaceutical industry. OBJECTIVE: Synthesis and evaluation of antitrypanosomal activities of a series of thiosemicarbazones and semicarbazones containing 1,2,3-1H triazole isatin scaffold. METHOD: 5'-(4-alkyl/aryl)-1H-1,2,3-triazole-isatins were prepared by Huisgen 1,3-dipolar cycloaddition and the thiosemicarbazones and semicarbazones were obtained by the 1:1 reactions of the carbonylated derivatives with thiosemicarbazide and semicarbazide hydrochloride, respectively, in methanol, using conventional reflux or microwave heating. The compounds were assayed for in vitro trypanocidal activity against Trypanosoma cruzi, the aetiological agent of Chagas disease. Beyond the thio/semicarbazone derivatives, isatin and triazole synthetic intermediates were also evaluated for comparison. RESULTS: A series of compounds were prepared in good yields. Among the 37 compounds evaluated, 18 were found to be active, in particular thiosemicarbazones containing a non-polar saturated alkyl chain (IC50 = 24.1, 38.6, and 83.2 µM; SI = 11.6, 11.8, and 14.0, respectively). To further elucidate the mechanism of action of these new compounds, the redox behaviour of some active and inactive derivatives was studied by cyclic voltammetry. Molecular docking studies were also performed in two validated protein targets of Trypanosoma cruzi, i.e., cruzipain (CRZ) and phosphodiesterase C (TcrPDEC). CONCLUSION: A class of thio/semicarbazones structurally simple and easily accessible was synthesized. Compounds containing thiosemicarbazone moieties showed the best results in the series, being more active than the corresponding semicarbazones. Our results indicated that the activity of these compounds does not originate from an oxidation-reduction pathway but probably from the interactions with trypanosomal enzymes.
Assuntos
Sobrevivência Celular/efeitos dos fármacos , Técnicas Eletroquímicas/métodos , Semicarbazonas/síntese química , Semicarbazonas/farmacologia , Análise Espectral/métodos , Tiossemicarbazonas/síntese química , Tiossemicarbazonas/farmacologia , Tripanossomicidas/síntese química , Tripanossomicidas/farmacologia , Animais , Linhagem Celular , Camundongos , Simulação de Acoplamento Molecular , Semicarbazonas/química , Relação Estrutura-Atividade , Tiossemicarbazonas/química , Tripanossomicidas/química , Trypanosoma cruzi/efeitos dos fármacosRESUMO
Endophytic fungi represent ubiquitous microbial organisms able to live in the tissues of different plants around the world and represent a prolific source of bioactive metabolites. In the present study, the endophytic fungus Aspergillus calidoustus was isolated from the medicinal plant Acanthospermum australe (Asteraceae), and identified using molecular, physiological and morphological methods. A methylene chloride crude extract of A. calidoustus has been produced and subjected to antifungal bioassay-directed fractionation which resulted in the isolation of the two bioactive compounds: ophiobolin K and 6-epi-ophiobolin K. These pure compounds displayed antifungal activity against fungal plant pathogens, protozoal activity against Trypanosoma cruzi, and cytotoxic activity against human tumoral cell lines. The results show that A. calidoustus was able to produce the antifungal and cytotoxic metabolites ophiobolin K and 6-epi-ophiobolin K, which may help the fungus to colonise and occupy the substratum as well as survive in natural environments.
Assuntos
Antifúngicos/química , Antimaláricos/química , Antineoplásicos/química , Aspergillus/química , Sesterterpenos/química , Antifúngicos/isolamento & purificação , Antimaláricos/isolamento & purificação , Antineoplásicos/isolamento & purificação , Asteraceae/microbiologia , Linhagem Celular Tumoral , HumanosRESUMO
Aiming to identify new sources of bioactive secondary metabolites, we isolated 82 endophytic fungi from stems and barks of the native Brazilian tree Caesalpinia echinata Lam. (Fabaceae). We tested their ethyl acetate extracts in several in vitro assays. The organic extracts from three isolates showed antibacterial activity against Staphylococcus aureus and Escherichia coli [minimal inhibitory concentration (MIC) 32-64 µg/mL]. One isolate inhibited the growth of Salmonella typhimurium (MIC 64 µg/mL) and two isolates inhibited the growth of Klebsiella oxytoca (MIC 64 µg/mL), Candida albicans and Candida tropicalis (MIC 64-128 µg/mL). Fourteen extracts at a concentration of 20 µg/mL showed antitumour activities against human breast cancer and human renal cancer cells, while two isolates showed anti-tumour activities against human melanoma cancer cells. Six extracts were able to reduce the proliferation of human peripheral blood mononuclear cells, indicating some degree of selective toxicity. Four isolates were able to inhibit Leishmania (Leishmania) amazonensis and one isolate inhibited Trypanosoma cruzi by at least 40% at 20 µg/mL. The trypanocidal extract obtained from Fusarium sp. [KF611679] culture was subjected to bioguided fractionation, which revealed beauvericin as the compound responsible for the observed toxicity of Fusarium sp. to T. cruzi. This depsipeptide showed a half maximal inhibitory concentration of 1.9 µg/mL (2.43 µM) in a T. cruzi cellular culture assay.
Assuntos
Caesalpinia/microbiologia , Depsipeptídeos/farmacologia , Endófitos/isolamento & purificação , Fusarium/isolamento & purificação , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Candida albicans/efeitos dos fármacos , Linhagem Celular Tumoral/efeitos dos fármacos , Fracionamento Químico , Misturas Complexas , Primers do DNA , Depsipeptídeos/isolamento & purificação , Endófitos/classificação , Enterobacteriaceae/efeitos dos fármacos , Fusarium/metabolismo , Bacilos Gram-Positivos Formadores de Endosporo/efeitos dos fármacos , Humanos , Leishmania/efeitos dos fármacos , Leucócitos Mononucleares/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Tripanossomicidas/isolamento & purificaçãoRESUMO
Aiming to identify new sources of bioactive secondary metabolites, we isolated 82 endophytic fungi from stems and barks of the native Brazilian tree Caesalpinia echinata Lam. (Fabaceae). We tested their ethyl acetate extracts in several in vitro assays. The organic extracts from three isolates showed antibacterial activity against Staphylococcus aureus and Escherichia coli [minimal inhibitory concentration (MIC) 32-64 μg/mL]. One isolate inhibited the growth of Salmonella typhimurium (MIC 64 μg/mL) and two isolates inhibited the growth of Klebsiella oxytoca (MIC 64 μg/mL), Candida albicans and Candida tropicalis (MIC 64-128 μg/mL). Fourteen extracts at a concentration of 20 μg/mL showed antitumour activities against human breast cancer and human renal cancer cells, while two isolates showed anti-tumour activities against human melanoma cancer cells. Six extracts were able to reduce the proliferation of human peripheral blood mononuclear cells, indicating some degree of selective toxicity. Four isolates were able to inhibit Leishmania (Leishmania) amazonensis and one isolate inhibited Trypanosoma cruzi by at least 40% at 20 μg/mL. The trypanocidal extract obtained from Fusarium sp. [KF611679] culture was subjected to bioguided fractionation, which revealed beauvericin as the compound responsible for the observed toxicity of Fusarium sp. to T. cruzi. This depsipeptide showed a half maximal inhibitory concentration of 1.9 μg/mL (2.43 μM) in a T. cruzi cellular culture assay.
Assuntos
Animais , Humanos , Antibacterianos/isolamento & purificação , Conservantes de Alimentos/isolamento & purificação , Myrica/química , Perciformes/microbiologia , Extratos Vegetais/isolamento & purificação , Folhas de Planta/química , Alimentos Marinhos/microbiologia , Antibacterianos/efeitos adversos , Antibacterianos/química , China , Qualidade dos Alimentos , Armazenamento de Alimentos , Conservantes de Alimentos/efeitos adversos , Conservantes de Alimentos/química , Doenças Transmitidas por Alimentos/microbiologia , Doenças Transmitidas por Alimentos/prevenção & controle , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/crescimento & desenvolvimento , Bactérias Gram-Positivas/isolamento & purificação , Concentração de Íons de Hidrogênio , Peroxidação de Lipídeos , Testes de Sensibilidade Microbiana , Oceano Pacífico , Proteólise , Extratos Vegetais/efeitos adversos , Extratos Vegetais/química , Alimentos Marinhos/análiseRESUMO
Annona cornifolia A. St. -Hil. is a small annual perennial tree found in the Brazilian savannah; their green fruit is popularly used in the treatment of ulcers. The acetogenins isolated from the seeds of Annona cornifolia previously showed to possess antioxidant activity. In continuation of our investigations on the biological activities of acetogenins, four binary mixtures and ten pure adjacent bis-tetrahydrofuran annonaceous acetogenins were evaluated: the cytotoxic (against three human tumor cell lines), antifungal (against Paracoccidioides brasiliensis), trypanocidal (against Trypanosoma cruzi) and leishmanicidal (against Leishmania amazonensis) activities. Acetogenins presented cytotoxic activity confirming their potential use in anti-cancer therapy. Regarding leishmanicidal and trypanocidal activities, an inhibition of 87% of L. amazonensis amastigotes and 100% of T. cruzi amastigotes and trypomastigotes was observed, when tested at the concentration of 20 µg mL-1. Moreover, six acetogenins showed more activity against all the three tested isolates of P. brasiliensis than trimethoprim-sulfamethoxazole, a drug used for treating paracoccidioidomycosis. Thus, acetogenins may be an alternative in treating a number of diseases that have a huge impact on millions of people worldwide. This paper reports for the first time the antifungal, leishmanicidal and trypanocidal activities for these acetogenins.
RESUMO
A total of 564 isolates of endophytic fungi were recovered from the plants Deschampsia antarctica and Colobanthus quitensis collected from Antarctica. The isolates were screened against parasites Leishmania amazonensis and Trypanosoma cruzi and against the human tumour cell lines. Of the 313 fungal isolates obtained from D. antarctica and 251 from C. quitensis, 25 displayed biological activity. Nineteen extracts displayed leishmanicidal activity, and six inhibited the growth of at least one tumour cell line. These fungi belong to 19 taxa of the genera Alternaria, Antarctomyces, Cadophora, Davidiella, Helgardia, Herpotrichia, Microdochium, Oculimacula, Phaeosphaeria and one unidentified fungus. Extracts of 12 fungal isolates inhibited the proliferation of L. amazonesis at a low IC(50) of between 0.2 and 12.5 µg ml(-1). The fungus Phaeosphaeria herpotrichoides displayed only leishmanicidal activity with an IC(50) of 0.2 µg ml(-1), which is equivalent to the inhibitory value of amphotericin B. The extract of Microdochium phragmitis displayed specific cytotoxic activity against the UACC-62 cell line with an IC(50) value of 12.5 µg ml(-1). Our results indicate that the unique angiosperms living in Antarctica shelter an interesting bioactive fungal community that is able to produce antiprotozoal and antitumoral molecules. These molecules may be used to develop new leishmanicidal and anticancer drugs.
Assuntos
Caryophyllaceae/microbiologia , Endófitos/fisiologia , Fungos/fisiologia , Leishmania , Neoplasias , Poaceae/microbiologia , Animais , Regiões Antárticas , Linhagem Celular Tumoral , Endófitos/química , Fungos/química , Humanos , Concentração Inibidora 50RESUMO
In areas where schistosomiasis is endemic, a negative correlation is observed between atopy and helminth infection, associated with a low prevalence of asthma. We investigated whether Schistosoma mansoni infection or injection of parasite eggs can modulate airway allergic inflammation in mice, examining the mechanisms of such regulation. We infected BALB/c mice with 30 S. mansoni cercariae or intraperitoneally injected 2,500 schistosome eggs, and experimental asthma was induced by ovalbumin (OVA). The number of eosinophils in bronchoalveolar lavage fluid was higher in the asthmatic group than in asthmatic mice infected with S. mansoni or treated with parasite eggs. Reduced Th2 cytokine production, characterized by lower levels of interleukin-4 (IL-4), IL-5, and immunoglobulin E, was observed in both S. mansoni-treated groups compared to the asthmatic group. There was a reduction in the number of inflammatory cells in lungs of S. mansoni-infected and egg-treated mice, demonstrating that both S. mansoni infection and the egg treatment modulated the lung inflammatory response to OVA. Only allergic animals that were treated with parasite eggs had increased numbers of CD4(+) CD25(+) Foxp3(+) T cells and increased levels of IL-10 and decreased production of CCL2, CCL3, and CCL5 in the lungs compared to the asthmatic group. Neutralization of IL-10 receptor or depletion of CD25(+) T cells in vivo confirmed the critical role of CD4(+) CD25(+) Foxp3(+) regulatory T cells in experimental asthma modulation independent of IL-10.
Assuntos
Antígenos de Protozoários/imunologia , Asma/imunologia , Linfócitos T CD4-Positivos/imunologia , Schistosoma mansoni/imunologia , Esquistossomose/imunologia , Subpopulações de Linfócitos T/imunologia , Animais , Asma/prevenção & controle , Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/citologia , Linfócitos T CD4-Positivos/química , Citocinas/análise , Eosinófilos/imunologia , Feminino , Citometria de Fluxo , Imunoglobulina E/análise , Subunidade alfa de Receptor de Interleucina-2/análise , Contagem de Leucócitos , Pulmão/patologia , Camundongos , Camundongos Endogâmicos BALB C , Esquistossomose/complicações , Subpopulações de Linfócitos T/químicaRESUMO
We investigated the role of different TLRs and MyD88 in host resistance to infection and malaria pathogenesis. TLR2(-/-), TLR4(-/-), TLR6(-/-), TLR9(-/-) or CD14(-/-) mice showed no change in phenotypes (parasitemia, body weight and temperature) when infected with Plasmodium chabaudi chabaudi (AS). MyD88(-/-) mice displayed comparable ability to wild type animals in controlling and clearing parasitemia. Importantly, MyD88(-/-) mice exhibited impaired production of TNF-alpha and IFN-gamma as well as attenuated symptoms, as indicated by changes in body weight and temperature during parasitemia. Consistently, CD11b(+) monocytes and CD11c(+) dendritic cells from infected MyD88(-/-) mice were shown impaired for production of pro-inflammatory cytokines, and in initiating CD4(+) T cell responses. Importantly, the inhibition of T cell activation with anti-CD134L, mostly inhibited IFN-gamma, partially inhibited TNF-alpha production, and protected the animals from malaria symptoms. Our findings suggest that MyD88 and possibly its associated TLRs expressed by dendritic cells play an important role in pro-inflammatory responses, T cell activation, and pathogenesis of malaria, but are not critical for the immunological control of the erythrocytic stage of P. chabaudi.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Células Dendríticas/imunologia , Malária/imunologia , Fator 88 de Diferenciação Mieloide/imunologia , Plasmodium chabaudi/imunologia , Receptores Toll-Like/imunologia , Animais , Citocinas/imunologia , Citometria de Fluxo , Imunofenotipagem , Ativação Linfocitária/imunologia , Malária/parasitologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Parasitemia/imunologia , Baço/imunologiaRESUMO
Thirty Boophilus microplus strains from various geographic regions of Brazil, Argentina, Uruguay, Venezuela and Colombia were analyzed for the bm86 and bm95 gene. A fragment of cDNA of 794 base pairs of the parasite larvae, included between nucleotides 278-1071s, was amplified and cloned on the pGEM-T vector. Two random clones were sequenced for each population and the nucleotides 278-1071 and predicted amino acid sequences compared with the bm86 and bm95 genes. Variations from 1.76 to 3.65% were detected in the nucleotides sequence when compared with the homologous sequence of the bm86 gene and a 3.4-6.08% in the homologous amino acid sequence of the Bm86 protein. When the sequences obtained were compared with the bm95 gene, variations from 0.50 to 3.15% were detected. Variations from 1.14 to 4.56% were detected for the Bm95 protein homologous sequences in the deduced amino acid sequence. Only five of the 30 strains analyzed presented two different types of alleles expressed and the two alleles of the Alegre population and allele 1 of the Betim population were the most divergent of all those analyzed.