RESUMO
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
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
Triptolide is a naturally occurring diterpene triepoxide whose anti-inflammatory effects correlate with transcriptional inhibition of various cytokines. Despite its use in herbal medicine for thousands of years, the cellular target and mode of action of this drug are unknown. [3H]-triptolide was prepared and a filtration assay designed to measure binding to cells and cellular extracts. Triptolide bound specifically and irreversibly to a single, 90 kDa protein in nuclear extracts from stimulated and non-stimulated monocytic and epithelial cell lines. Thiol reactivity of one or more of the epoxides on triptolide was necessary for the covalent binding, since thiol oxidizing agents dithiodipyridine and diamide, and the thiol alkylating agent N-ethylmaleimide all reduced the binding of [3H]-triptolide to nuclear extract. Neither glutathione nor the pro-oxidant tert-butylhydroperoxide affected the binding of [3H]-triptolide to the nuclear protein, ruling out a general oxidant effect. The number of epoxide moieties correlated with the ability to compete with radiolabeled triptolide for binding to the nuclear extract and with the potency of inhibition of TNFalpha secretion from monocytes, IL-2 secretion from Jurkat cells, and with inhibition of RNA synthesis. The correlation between the structure-activity relationship and observed binding suggests that identification of the triptolide binding protein could provide insight into the cellular mode of action of this anti-inflammatory natural product.
Assuntos
Citocinas/biossíntese , Diterpenos/metabolismo , Compostos de Epóxi/metabolismo , Proteínas Nucleares/metabolismo , Fenantrenos/metabolismo , Apoptose , Linhagem Celular , Citocinas/imunologia , Diterpenos/química , Compostos de Epóxi/química , Humanos , NF-kappa B/metabolismo , Fenantrenos/químicaRESUMO
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
Diaryl imidazo[1,2-a]pyridine derivatives, such as 6a and 7i, have been synthesized and found to be potent inhibitors of parasite PKG activity. The most potent compounds are the 7-isopropylaminomethyl analog 6a and 2-isopropylamino analog 7i. These compounds are also fully active in in vivo assay as anticoccidial agents at 25 ppm in feed.
Assuntos
Coccidiose/tratamento farmacológico , Coccidiostáticos/farmacologia , Imidazóis/química , Inibidores de Proteínas Quinases/farmacologia , Piridinas/química , Piridinas/farmacologia , Animais , Química Farmacêutica/métodos , Coccidiostáticos/química , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Desenho de Fármacos , Eimeria tenella , Modelos Químicos , Inibidores de Proteínas Quinases/química , Relação Estrutura-AtividadeRESUMO
Parasite cGMP-dependent protein kinase (PKG) is one of the validated biochemical targets for the treatment of coccidiosis. We screened our library of natural product extracts for inhibitors of parasite PKG for the discovery of anticoccidial leads. Terferol (1) and three new terphenyls (2, 3, and 4) were isolated using bioassay-guided fractionation of the microbial extract of a Phoma sp. by a high-throughput two-step isolation method employing LH-20 and reversed-phase HPLC. These compounds inhibited parasite PKG with IC(50) values in the range 0.9-5.8 microM.
Assuntos
Ascomicetos/química , Coccidiose/tratamento farmacológico , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Eimeria tenella/efeitos dos fármacos , Inibidores Enzimáticos , Compostos de Terfenil , Animais , Inibidores Enzimáticos/química , Inibidores Enzimáticos/isolamento & purificação , Inibidores Enzimáticos/farmacologia , França , Estrutura Molecular , Compostos de Terfenil/química , Compostos de Terfenil/isolamento & purificação , Compostos de Terfenil/farmacologiaRESUMO
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
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
Compounds 10a (IC50 110 pM) and 21 (IC50 40 pM) are the most potent inhibitors of Eimeria tenella cGMP-dependent protein kinase activity reported to date and are efficacious in the in vivo antiparasitic assay when administered to chickens at 12.5 and 6.25 ppm levels in the feed. However, both compounds are positive in the Ames microbial mutagenesis assay which precludes them from further development as antiprotozoal agents in the absence of negative lifetime rodent carcinogenicity studies.
Assuntos
Antiprotozoários/síntese química , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Eimeria tenella/efeitos dos fármacos , Inibidores Enzimáticos/síntese química , Imidazóis/síntese química , Piridinas/síntese química , Ração Animal , Animais , Antiprotozoários/química , Antiprotozoários/farmacologia , Galinhas , Coccidiose/tratamento farmacológico , Eimeria tenella/enzimologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Imidazóis/química , Imidazóis/farmacologia , Masculino , Estrutura Molecular , Testes de Mutagenicidade , Oocistos/efeitos dos fármacos , Testes de Sensibilidade Parasitária , Piridinas/química , Piridinas/farmacologia , Ratos , Ratos Sprague-Dawley , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
Parasite cGMP-dependent protein kinase (PKG) has been recently validated as a biochemical target for the treatment of coccidiosis. To discover new anticoccidial leads, we have screened our library of natural product extracts for inhibitors of parasite PKG. Bioassay-guided fractionation of the microbial extracts has led to the discovery of tenellones A (2) and B (3), two new highly substituted benzophenones. The isolation, structure, and activity of these compounds are described.
Assuntos
Benzofenonas/isolamento & purificação , Inibidores Enzimáticos/isolamento & purificação , Fungos/química , Animais , Benzofenonas/química , Benzofenonas/farmacologia , Proteínas Quinases Dependentes de GMP Cíclico , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Estrutura Molecular , Plantas Medicinais/química , Espanha , Toxoplasma/metabolismoRESUMO
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
Diaryl-(4-piperidinyl)-pyrrole derivatives bearing hydroxylated N-alkyl substituents have been synthesized and evaluated as anticoccidial agents. High potency in Et-PKG inhibition and broad-spectrum anticoccidial activities have been observed on compounds, such as 4b and 5h, which are fully efficacious in vivo at 50 ppm in feed.
Assuntos
Coccidiostáticos/química , Coccidiostáticos/farmacologia , Pirróis/química , Pirróis/farmacologia , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Hidroxilação , Relação Estrutura-AtividadeRESUMO
The trisubstituted pyrrole 4-[2-(4-fluorophenyl)-5-(1-methylpiperidine-4-yl)-1H-pyrrol-3-yl]pyridine (Compound 1) inhibits the growth of Eimeria spp. both in vitro and in vivo. The molecular target of Compound 1 was identified as cGMP-dependent protein kinase (PKG) using a tritiated analogue to purify a approximately 120-kDa protein from lysates of Eimeria tenella. This represents the first example of a protozoal PKG. Cloning of PKG from several Apicomplexan parasites has identified a parasite signature sequence of nearly 300 amino acids that is not found in mammalian or Drosophila PKG and which contains an additional, third cGMP-binding site. Nucleotide cofactor regulation of parasite PKG is remarkably different from mammalian enzymes. The activity of both native and recombinant E. tenella PKG is stimulated 1000-fold by cGMP, with significant cooperativity. Two isoforms of the parasite enzyme are expressed from a single copy gene. NH(2)-terminal sequence of the soluble isoform of PKG is consistent with alternative translation initiation within the open reading frame of the enzyme. A larger, membrane-associated isoform corresponds to the deduced full-length protein sequence. Compound 1 is a potent inhibitor of both soluble and membrane-associated isoforms of native PKG, as well as recombinant enzyme, with an IC(50) of <1 nm.