RESUMO
Screening of our chemical library to discover new molecules exhibiting in vitro activity against the invasion of host cells by Eimeria tenella revealed a lead compound with an IC50 of 15µM. Structure-activity relationship studies were conducted with 34 newly synthesized compounds to identify more active molecules and enhance in vitro activity against the parasite. Four compounds were more effective in inhibiting MDBK cell invasion in vitro than the lead compound.
Assuntos
Coccidiose/tratamento farmacológico , Coccidiostáticos/síntese química , Coccidiostáticos/farmacologia , Eimeria tenella/efeitos dos fármacos , Piridonas/farmacologia , Pirimidinonas/farmacologia , Animais , Bovinos , Sobrevivência Celular/efeitos dos fármacos , Coccidiostáticos/química , Relação Dose-Resposta a Droga , Estrutura Molecular , Testes de Sensibilidade Parasitária , Piridonas/síntese química , Piridonas/química , Pirimidinonas/síntese química , Pirimidinonas/química , Relação Estrutura-AtividadeRESUMO
Toxoplasmosis is a disease of prominent health concern that is caused by the protozoan parasite Toxoplasma gondii. Proliferation of T. gondii is dependent on its ability to invade host cells, which is mediated in part by calcium-dependent protein kinase 1 (CDPK1). We have developed ATP competitive inhibitors of TgCDPK1 that block invasion of parasites into host cells, preventing their proliferation. The presence of a unique glycine gatekeeper residue in TgCDPK1 permits selective inhibition of the parasite enzyme over human kinases. These potent TgCDPK1 inhibitors do not inhibit the growth of human cell lines and represent promising candidates as toxoplasmosis therapeutics.
Assuntos
Coccidiostáticos/síntese química , Inibidores de Proteínas Quinases/síntese química , Proteínas Quinases/metabolismo , Proteínas de Protozoários/antagonistas & inibidores , Pirazóis/síntese química , Pirimidinas/síntese química , Toxoplasma/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Coccidiostáticos/química , Coccidiostáticos/farmacologia , Cristalografia por Raios X , Resistência a Medicamentos , Ensaios Enzimáticos , Humanos , Modelos Moleculares , Estrutura Molecular , Naftalenos/síntese química , Naftalenos/química , Naftalenos/farmacologia , Piperidinas/síntese química , Piperidinas/química , Piperidinas/farmacologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas de Protozoários/metabolismo , Pirazóis/química , Pirazóis/farmacologia , Pirimidinas/química , Pirimidinas/farmacologia , Relação Estrutura-Atividade , Toxoplasma/enzimologiaRESUMO
In poultry farming, anticoccidial drugs are widely used as feed additives for the prevention and treatment of coccidiosis. Because coccidiostats and veterinary medicines, in general, are often poorly absorbed, manure from treated animals may contain high concentrations of these compounds. Experimental studies have shown that the uptake of veterinary medicines by plants from soil containing contaminated manure may occur. This leads to several questions regarding the impact on the environment, resistance problems, and public health and allergy issues. This work describes the development of a quantification method for coccidiostats in vegetables. Vegetables were spiked at 100 µg kg(-1) (dry weight) with coccidiostats (monensin, narasin, lasalocid A, salinomycin, diclazuril, and nicarbazin) in order to optimize the extraction and clean-up. Possible critical factors (e.g., extraction solvent) were statistically examined by linear regression with the use of Plackett-Burman and full factorial designs. Final extracts were analyzed with ultra-performance liquid chromatography tandem mass spectrometry operating in multiple-reaction monitoring mode. Both the synthetic and ionophoric coccidiostats could be determined in a single run with an analysis time of 5 min. The developed method was validated taking into account the requirements of the Commission Decision 2002/657/EC as a guideline. The method is regarded as applicable for its intended purposes with quantification limits between 0.30 and 2.98 µg kg(-1). This method could be used to establish possible maximum residue limits for coccidiostats in vegetables, as already exist for eggs, meat, and milk.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Coccidiostáticos/análise , Ionóforos/análise , Espectrometria de Massas em Tandem/métodos , Verduras/química , Coccidiostáticos/síntese química , Contaminação de Alimentos/análiseRESUMO
Toxoplasmosis causes significant morbidity and mortality, and yet available medicines are limited by toxicities and hypersensitivity. Because improved medicines are needed urgently, rational approaches were used to identify novel lead compounds effective against Toxoplasma gondii enoyl reductase (TgENR), a type II fatty acid synthase enzyme essential in parasites but not present in animals. Fifty-three compounds, including three classes that inhibit ENRs, were tested. Six compounds have antiparasite MIC(90)s < or = 6 microM without toxicity to host cells, three compounds have IC(90)s < 45 nM against recombinant TgENR, and two protect mice. To further understand the mode of inhibition, the cocrystal structure of one of the most promising candidate compounds in complex with TgENR has been determined to 2.7 A. The crystal structure reveals that the aliphatic side chain of compound 19 occupies, as predicted, space made available by replacement of a bulky hydrophobic residue in homologous bacterial ENRs by Ala in TgENR. This provides a paradigm, conceptual foundation, reagents, and lead compounds for future rational development and discovery of improved inhibitors of T. gondii.
Assuntos
Coccidiostáticos/síntese química , Enoil-(Proteína de Transporte de Acila) Redutase (NADH)/antagonistas & inibidores , Nitrilas/síntese química , Éteres Fenílicos/síntese química , Piridinas/síntese química , Toxoplasma/efeitos dos fármacos , Animais , Células Cultivadas , Coccidiostáticos/química , Coccidiostáticos/farmacologia , Cristalografia por Raios X , Inibidores das Enzimas do Citocromo P-450 , Fibroblastos/efeitos dos fármacos , Fibroblastos/parasitologia , Humanos , Técnicas In Vitro , Camundongos , Testes de Sensibilidade Microbiana , Microssomos Hepáticos/metabolismo , Modelos Moleculares , Estrutura Molecular , Nitrilas/química , Nitrilas/farmacologia , Nitrobenzenos/síntese química , Nitrobenzenos/química , Nitrobenzenos/farmacologia , Éteres Fenílicos/química , Éteres Fenílicos/farmacologia , Piridinas/química , Piridinas/farmacologia , Relação Estrutura-Atividade , Toxoplasma/enzimologia , Toxoplasmose/tratamento farmacológicoRESUMO
Novel 2,3-diarylindoles bearing an amine substituent at the indole 5- and 6-positions have been synthesized and evaluated as anticoccidial agents in both in vitro and in vivo assays. Both subnanomolar in vitro activity and broad spectrum in vivo potency were detected for several compounds, particularly compound 27.
Assuntos
Coccidiostáticos/síntese química , Indóis/síntese química , Animais , Coccidiose/tratamento farmacológico , Coccidiose/enzimologia , Coccidiose/parasitologia , Coccidiostáticos/farmacologia , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Eimeria tenella/efeitos dos fármacos , Eimeria tenella/enzimologia , Eimeria tenella/crescimento & desenvolvimento , Indóis/farmacologia , Aves Domésticas/parasitologia , Piridinas/síntese químicaRESUMO
A series of ethyl 6-arylmethoxy-7-alkoxy-4-hydroxy-3-quinolinecarboxylates was synthesized as anticoccidial medicine, and their structures were characterized by 1H NMR, MS, and IR spectra. Anticoccidial activities of these compounds were evaluated according to the anticoccidial index method. The results indicated that five of these compounds exhibited anticoccidial activities against Eimeria tenella in the chicken's diet with a dose of 27 mg/kg. In particular, the anticoccidial index of ethyl 6-(2,5-dimethylbenzyloxy)-7-methoxy-4-hydroxy-3-quinolinecarboxylate and ethyl 6-(2,5-dimethylbenzyloxy)-7-ethoxy-4-hydroxy-3-quinolinecarboxylate was 169.3 and 175.1, respectively, which indicated that the two compounds have high anticoccidial activity.
Assuntos
Coccidiostáticos/síntese química , Eimeria tenella/efeitos dos fármacos , Quinolinas/síntese química , Animais , Galinhas , Coccidiostáticos/química , Coccidiostáticos/uso terapêutico , Alimentos , Doenças das Aves Domésticas/parasitologia , Doenças das Aves Domésticas/prevenção & controle , Infecções Protozoárias em Animais/parasitologia , Infecções Protozoárias em Animais/prevenção & controle , Quinolinas/química , Quinolinas/uso terapêuticoRESUMO
Novel 5,6-diarylimidazo[2,1-b][1,3]thiazoles bearing an amine substituent at the imidazothiazole 2-position have been synthesized and evaluated as anticoccidial agents in both in vitro and in vivo assays. Both subnanomolar in vitro activity and broad spectrum in vivo potency were detected for several compounds, particularly compound 10.
Assuntos
Coccidiostáticos/síntese química , Coccidiostáticos/farmacologia , Imidazóis/síntese química , Imidazóis/farmacologia , Tiazóis/síntese química , Tiazóis/farmacologia , Animais , Coccidiostáticos/química , Técnicas de Química Combinatória , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Eimeria/efeitos dos fármacos , Imidazóis/química , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Tiazóis/químicaRESUMO
Diaryl-(4-piperidinyl)-pyrrole derivatives bearing cyclic amine substituents have been synthesized and evaluated as anticoccidial agents. Improvements in potency of Et-PKG inhibition, such as azetidine derivative 3a, and broad spectrum anticoccidial activities in feed, such as morpholine derivative 8c, have been achieved.
Assuntos
Coccidiose/tratamento farmacológico , Coccidiostáticos/farmacologia , Eimeria/efeitos dos fármacos , Pirróis/farmacologia , Animais , Galinhas , Coccidiostáticos/síntese química , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Eimeria/enzimologia , Feminino , Estrutura Molecular , Oocistos/efeitos dos fármacos , Oocistos/fisiologia , Inibidores de Proteínas Quinases/farmacologia , Pirróis/síntese química , Pirróis/química , Relação Estrutura-AtividadeRESUMO
Coccidiosis is the major cause of morbidity and mortality in the poultry industry. Protozoan parasites of the genus Eimeria invade the intestinal lining of the avian host causing tissue pathology, poor weight gain, and in some cases mortality. Resistance to current anticoccidials has prompted the search for new therapeutic agents with potent in vitro and in vivo activity against Eimeria. Recently, we reported the synthesis and biological activity of potent imidazo[1,2-a]pyridine anticoccidial agents. Antiparasitic activity is due to inhibition of a parasite specific cGMP-dependent protein kinase (PKG). In this study, we report the synthesis and anticoccidial activity of a second set of such compounds, focusing on derivatization of the amine side chain at the imidazopyridine 7-position. From this series, several compounds showed subnanomolar in vitro activity and commercial levels of in vivo activity. However, the potential genotoxicity of these compounds precludes them from further development.
Assuntos
Coccidiostáticos/síntese química , Coccidiostáticos/farmacologia , Piridinas/síntese química , Piridinas/farmacologia , Animais , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Eimeria/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacologia , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Coccidiosis is the major cause of morbidity and mortality in the poultry industry. Protozoan parasites of the genus Eimeria invade the intestinal lining of the avian host causing tissue pathology, poor weight gain, and in some cases mortality. Resistance to current anticoccidials has prompted the search for new therapeutic agents with potent in vitro and in vivo activity against Eimeria. Antiparasitic activity is due to inhibition of a parasite specific cGMP-dependent protein kinase (PKG). In this study, we present the synthesis and biological activity of imidazo[1,2-a]pyridine anticoccidial agents. From this series, several compounds showed subnanomolar in vitro activity and commercial levels of in vivo activity. However, the potential genotoxicity of these compounds precludes them from further development.
Assuntos
Coccidiostáticos/síntese química , Coccidiostáticos/farmacologia , Eimeria/efeitos dos fármacos , Imidazóis/síntese química , Imidazóis/farmacologia , Piridinas/síntese química , Piridinas/farmacologia , Animais , Disponibilidade Biológica , Coccidiostáticos/química , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Eimeria/fisiologia , Imidazóis/química , Concentração Inibidora 50 , Piridinas/químicaRESUMO
In this work we report a QSAR model that discriminates between chemically heterogeneous classes of anticoccidial and non-anticoccidial compounds. For this purpose we used the Markovian Chemicals in silico Design (MARCH-INSIDE) approach J. Mol. Mod.2002, 8, 237-245; J. Mol. Mod.2003, 9, 395-407]. Linear discriminant analysis allowed us to fit the discriminant function. This function correctly classifies 86.67% of anticoccidial compounds and 96.23% of inactive compounds in the training series. Overall classification is 94.12%. We validated the model by means of an external predicting series, with 86.96% of global predictability. Remarkably, the present model is based on topological as well as configuration-dependent molecular descriptors. Therefore, the model performs timely calculations and allows discrimination between Z/E and chiral isomers. Finally, to exemplify the use of the model in practice we report the prediction and experimental assay of trans-2-(2-nitrovinyl)furan. It is notable that lesion control was 72.86% at mg/kg of body weight with respect to 60% at 125 mg/kg for amprolium (control drug). The back-projection map for this compound predicts a high level of importance for the double bond and for the nitro group in the trans position. We conclude that the MARCH-INSIDE approach enables the accurate fast track identification of anticoccidial hits. Moreover, trans-2-(2-nitrovinyl)furan seems to be a promising drug for the treatment of coccidiosis.
Assuntos
Coccidiostáticos/síntese química , Coccidiostáticos/farmacologia , Furanos/síntese química , Furanos/farmacologia , Compostos de Vinila/síntese química , Compostos de Vinila/farmacologia , Animais , Peso Corporal/efeitos dos fármacos , Galinhas , Eimeria tenella/efeitos dos fármacos , Feminino , Modelos Moleculares , Relação Quantitativa Estrutura-Atividade , Reprodutibilidade dos TestesRESUMO
Compounds 10a-10d and 10i are very potent inhibitors of Eimeria tenella cGMP-dependent protein kinase (0.081-0.32 nM) and are very efficacious antiparasitic agents in vivo when administered to chickens at 12.5-25 ppm levels in the feed.
Assuntos
Coccidiostáticos/síntese química , Coccidiostáticos/farmacologia , Imidazóis/síntese química , Imidazóis/farmacologia , Piridinas/química , Piridinas/síntese química , Piridinas/farmacologia , Animais , Coccidiostáticos/química , Eimeria/efeitos dos fármacos , Imidazóis/química , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
2-(4-Fluorophenyl)-3-(4-pyridinyl)-5-substituted pyrroles were prepared and evaluated as anticoccidial agents in both in vitro and in vivo assays. Among the compounds evaluated, the dimethylamine-substituted pyrrole 19a is the most potent inhibitor of Eimeria tenella PKG (cGMP-dependent protein kinase). Further SAR studies on the side chain of the 2-pyrrolidine nitrogen did not enhance in vivo anticoccidial activity.
Assuntos
Coccidiostáticos/síntese química , Coccidiostáticos/farmacologia , Pirróis/síntese química , Pirróis/farmacologia , Animais , Coccidiostáticos/química , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Eimeria tenella/efeitos dos fármacos , Eimeria tenella/enzimologia , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Pirróis/química , Relação Estrutura-AtividadeRESUMO
We report the preparation and antiparasitic activity in vitro and in vivo of a series of isoflavone derivatives related to genistein. These analogues retain the 5,7-dihydroxyisoflavone core of genistein: direct genistein analogues (2-H isoflavones), 2-carboethoxy isoflavones, and the precursor deoxybenzoins were all evaluated. Excellent in vitro activity against Cryptosporidium parvum was observed for both classes of isoflavones in cell cultures, and the lead compound 19, RM6427, shows high in vivo efficacy against an experimental infection.
Assuntos
Coccidiostáticos/síntese química , Cryptosporidium parvum/efeitos dos fármacos , Isoflavonas/síntese química , Animais , Bovinos , Linhagem Celular Tumoral , Coccidiostáticos/farmacologia , Criptosporidiose/tratamento farmacológico , Cryptosporidium parvum/isolamento & purificação , Feminino , Genisteína/análogos & derivados , Genisteína/síntese química , Genisteína/farmacologia , Gerbillinae , Humanos , Hospedeiro Imunocomprometido , Isoflavonas/farmacologia , Masculino , Relação Estrutura-AtividadeRESUMO
Several analogs of 2,3-diaryl pyrroles were synthesized and evaluated as inhibitors of Eimeria tenella cGMP-dependent protein kinase and in in vivo anticoccidial assays. A 4-fluorophenyl group enhances both in vitro and in vivo activities. The most potent analogs are the 5-(N-methyl, N-ethyl, and N-methylazetidine methyl) piperidyl derivatives 12, 23, and 34. These compounds have a broad spectrum of activity. Based on the in vivo efficacy and cost of synthesis, the N-ethyl analog 23 was chosen as a novel anticoccidial agent for a field trial.
Assuntos
Coccidiostáticos/síntese química , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Proteínas de Protozoários/antagonistas & inibidores , Pirróis/síntese química , Animais , Disponibilidade Biológica , Galinhas , Coccidiose/tratamento farmacológico , Coccidiostáticos/farmacocinética , Coccidiostáticos/farmacologia , Eimeria , Meia-Vida , Concentração Inibidora 50 , Pirróis/farmacocinética , Pirróis/farmacologia , Relação Estrutura-AtividadeRESUMO
Toxoplasma gondii is the most common cause of secondary CNS infections in immunocompromised persons such as AIDS patients. The major route of adenosine metabolism in T. gondii is direct phosphorylation to adenosine 5'-monophosphate (AMP) catalyzed by the enzyme adenosine kinase (EC 2.7.1.20). Adenosine kinase in T. gondii is significantly more active than any other purine salvage enzyme in this parasite and has been established as a potential chemotherapeutic target for the treatment of toxoplasmosis. Subversive substrates of T. gondii,but not the human, adenosine kinase are preferentially metabolized to their monophosphorylated forms and become selectively toxic to the parasites but not their host. 6-Benzylthioinosine (BTI) was identified as an excellent subversive substrate of T. gondii adenosine kinase. Herein, we report the synthesis of new analogues of BTI as subversive substrates for T. gondii adenosine kinase. These new subversive substrates were synthesized starting from tribenzoyl protected d-ribose. To accomplish the lead optimization process, a divergent and focused combinatorial library was synthesized using a polymer-supported trityl group at the 5'-position. The combinatorial library of 20 compounds gave several compounds more active than BTI. Structure-activity relationship studies showed that substitution at the para position plays a crucial role. To investigate the reasons for this discrimination, substrates with different substituents at the para position were studied by molecular modeling using Monte Carlo Conformational Search followed by energy minimization of the enzyme-ligand complex.
Assuntos
Adenosina Quinase/metabolismo , Tioinosina/síntese química , Toxoplasma/enzimologia , Adenosina Quinase/química , Adenosina Quinase/deficiência , Animais , Células Cultivadas , Coccidiostáticos/síntese química , Coccidiostáticos/química , Coccidiostáticos/farmacologia , Técnicas de Química Combinatória , Humanos , Modelos Moleculares , Relação Estrutura-Atividade , Tioinosina/análogos & derivados , Tioinosina/química , Tioinosina/farmacologia , Toxoplasma/efeitos dos fármacosRESUMO
The synthesis of several acridinic thioethers is described. Compounds prepared were tested in vitro as potential drugs against the opportunistic infection known as cryptosporidiosis. With a view to predict activity, the quantitative structure-activity relationships were investigated. Correlations between experimental data and either log P or pKa are discussed.
Assuntos
Acridinas/síntese química , Coccidiostáticos/síntese química , Cryptosporidium parvum/efeitos dos fármacos , Acridinas/farmacologia , Acridinas/uso terapêutico , Animais , Animais Recém-Nascidos , Bovinos , Linhagem Celular , Coccidiostáticos/farmacologia , Coccidiostáticos/uso terapêutico , Criptosporidiose/tratamento farmacológico , Criptosporidiose/parasitologia , Cryptosporidium parvum/crescimento & desenvolvimento , Fezes/parasitologia , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética , Relação Estrutura-AtividadeRESUMO
Several quinazoline derivatives containing substituted thiosemicarbazido and S-methylisothiosemicarbazido groups at the 2-position and at both the 2- and 4-positions have been synthesized. Treatment of the S-methylthiosemicarbazides with morpholine or diethylamine did not give the corresponding guanidines. Instead, they underwent cyclodesulfurization into the condensed ring systems, [1,2,4]triazolo[4,3-a]quinazolinones and bis-[1,2,4]triazolo[4,3-a:4'.3'-c]quinazolines. Evaluation of the products for antitoxoplasmosis effect by studying the ultrastructure morphology of the organisms using scanning electron microscopy (SEM) indicated their efficacy in causing structural deformity of Toxoplasma gondii. Such a deformity plays an important role in obstructing the entry of the organisms into host cells.
Assuntos
Coccidiostáticos/síntese química , Quinazolinas/síntese química , Toxoplasma/efeitos dos fármacos , Triazóis/síntese química , Animais , Anti-Infecciosos/farmacologia , Coccidiostáticos/farmacologia , Camundongos , Pirimetamina/farmacologia , Quinazolinas/farmacologia , Quinazolinonas , Toxoplasma/ultraestrutura , Toxoplasmose Animal/tratamento farmacológico , Toxoplasmose Animal/parasitologia , Triazóis/farmacologiaRESUMO
[formula: see text] The proposed structure of fudecalone (1), an anticoccidial drimane sesquiterpene, was synthesized as a racemate in six steps starting from a known phthalide (5). Interestingly, our synthetic 1 showed conformation 1b, while the natural one was reported as 1a, and the NMR spectral data were not identical.
Assuntos
Coccidiostáticos/síntese química , Naftalenos/síntese química , Coccidiostáticos/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Naftalenos/químicaRESUMO
The reactions of 3-alkyl(aryl)-4-phenylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones with appropriate alkyl halides via sodio derivatives were studied and the corresponding 1-alkyl-3-alkyl(aryl)-4-phenylamino-4,5-dihydro-1H-1,2,4-traizol-5 -ones were synthesized. Next, the new compounds were tested for their in vitro antimicrobial activities.