RESUMEN
A high-throughput screening program identified two piperazine sulfonamides with activity against Plasmodium falciparum. Both screening positives had three structural features with potential liabilities: furanyl, thiourea and nitrophenyl groups. The furan could be replaced with no loss of activity, replacement of the nitrophenyl led to some loss of activity, and any attempt to replace the thiourea led to a significant decrease in activity, which implicates this reactive functional group's role in the antiplasmodial activity of this compound class.
Asunto(s)
Antimaláricos/química , Piperazinas/química , Sulfonamidas/química , Antimaláricos/síntesis química , Antimaláricos/farmacología , Furanos/química , Ensayos Analíticos de Alto Rendimiento , Piperazina , Plasmodium falciparum/efectos de los fármacos , Sulfonamidas/síntesis química , Sulfonamidas/farmacología , Tiourea/químicaRESUMEN
Two sets of diaminopyrimidines, totalling 45 compounds, were synthesized and assayed against Plasmodium falciparum. The SAR was relatively shallow, with only the presence of a 2-(pyrrolidin-1-yl)ethyl group at R(2) significantly affecting activity. A subsequent series addressed high LogD values by introducing more polar side groups, with the most active compounds possessing diazepine and N-benzyl-4-aminopiperidyl groups at R(1)/R(2). A final series attempted to address high in vitro microsomal clearance by replacing the C6-Me group with CF(3), however antiplasmodial activity decreased without any improvement in clearance. The C6-CF(3) group decreased hERG inhibition, probably as a result of decreased amine basicity at C2/C4.
Asunto(s)
Antimaláricos/síntesis química , Pirimidinas/química , Animales , Antimaláricos/química , Antimaláricos/farmacología , Canales de Potasio Éter-A-Go-Go/metabolismo , Humanos , Microsomas Hepáticos/metabolismo , Plasmodium falciparum/efectos de los fármacos , Pirimidinas/síntesis química , Pirimidinas/farmacología , Ratas , Relación Estructura-ActividadRESUMEN
A 43-member 1,2-dioxolane library was synthesized by coupling a 1,2-dioxolane-3-acetic acid derivative to a range of amines. Ten compounds had EC(50)s30nM against Plasmodium falciparum 3D7 and Dd2 strains, and another 15 compounds had EC(50)s50nM against both 3D7 and Dd2. The library was then subjected to a range of in vitro DMPK assays, which revealed that side chains with a heteroatom were required for favorable solubility, LogD and membrane permeability. CYP450 inhibition was isoform dependent, with 2C19 and 3A4 particularly susceptible, and the majority of compounds tested against rat and human microsomes were metabolized rapidly.
Asunto(s)
Antimaláricos/síntesis química , Antimaláricos/metabolismo , Inhibidores Enzimáticos del Citocromo P-450 , Dioxolanos/síntesis química , Dioxolanos/metabolismo , Plasmodium falciparum/efectos de los fármacos , Animales , Antimaláricos/farmacología , Sistema Enzimático del Citocromo P-450/metabolismo , Dioxolanos/farmacología , Humanos , Microsomas Hepáticos/metabolismo , Isoformas de Proteínas/antagonistas & inhibidores , Isoformas de Proteínas/metabolismo , Ratas , Bibliotecas de Moléculas PequeñasRESUMEN
Artemisinin-derived compounds play an integral role in current malaria chemotherapy. Given the virtual certainty of emerging resistance, we have investigated spiro-1,2-dioxolanes as an alternative scaffold. The endoperoxide functionality was generated by the SnCl(4)-mediated annulation of a bis-silylperoxide and an alkene. The first set of eight analogs gave EC(50) values of 50-150 nM against Plasmodium falciparum 3D7 and Dd2 strains, except for the carboxylic acid analog. A second series, synthesized by coupling a spiro-1,2-dioxolane carboxylic acid to four separate amines, afforded the most potent compound (EC(50) approximately 5 nM).
Asunto(s)
Antiprotozoarios/síntesis química , Antiprotozoarios/farmacología , Dioxolanos/química , Aminas/química , Secuencias de Aminoácidos , Animales , Antígenos de Protozoos/química , Antimaláricos/síntesis química , Antimaláricos/farmacología , Química Farmacéutica , Diseño de Fármacos , Hemo/química , Humanos , Malaria/tratamiento farmacológico , Modelos Químicos , Peróxidos/química , Plasmodium falciparumRESUMEN
Clinical malaria is associated with the proliferation of Plasmodium parasites in human erythrocytes. The coordinated processes of parasite egress from and invasion into erythrocytes are rapid and tightly regulated. We have found that the plant-like calcium-dependent protein kinase PfCDPK5, which is expressed in invasive merozoite forms of Plasmodium falciparum, was critical for egress. Parasites deficient in PfCDPK5 arrested as mature schizonts with intact membranes, despite normal maturation of egress proteases and invasion ligands. Merozoites physically released from stalled schizonts were capable of invading new erythrocytes, separating the pathways of egress and invasion. The arrest was downstream of cyclic guanosine monophosphate-dependent protein kinase (PfPKG) function and independent of protease processing. Thus, PfCDPK5 plays an essential role during the blood stage of malaria replication.
Asunto(s)
Proteínas de Unión al Calcio/metabolismo , Eritrocitos/parasitología , Plasmodium falciparum/fisiología , Proteínas Quinasas/metabolismo , Proteínas Protozoarias/metabolismo , Proteínas de Unión al Calcio/química , Proteínas de Unión al Calcio/genética , Proteínas Quinasas Dependientes de GMP Cíclico/antagonistas & inhibidores , Proteínas Quinasas Dependientes de GMP Cíclico/metabolismo , Inhibidores Enzimáticos/farmacología , Interacciones Huésped-Parásitos , Humanos , Ligandos , Merozoítos/enzimología , Merozoítos/fisiología , Modelos Biológicos , Morfolinas/metabolismo , Plasmodium falciparum/citología , Plasmodium falciparum/enzimología , Plasmodium falciparum/crecimiento & desarrollo , Proteínas Quinasas/química , Proteínas Quinasas/genética , Proteínas Protozoarias/química , Proteínas Protozoarias/genética , Piridinas/farmacología , Pirroles/farmacología , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/metabolismo , Esquizontes/citología , Esquizontes/enzimología , Esquizontes/fisiologíaRESUMEN
Trypanothione reductase (TR), an enzyme that buffers oxidative stress in trypanosomatid parasites, was screened against commercial libraries containing approximately 134,500 compounds. After secondary screening, four chemotypes were identified as screening positives with selectivity for TR over human glutathione reductase. Thirteen compounds from these four chemotypes were purchased, and their in vitro activity against TR and Trypanosoma brucei is described.
Asunto(s)
Evaluación Preclínica de Medicamentos/métodos , NADH NADPH Oxidorreductasas/antagonistas & inhibidores , Tripanocidas/química , Trypanosoma brucei brucei/efectos de los fármacos , Animales , Inhibidores Enzimáticos , Glutatión Reductasa , Humanos , Relación Estructura-Actividad , Trypanosoma/efectos de los fármacos , Trypanosoma/enzimologíaRESUMEN
13C NMR and mass spectrometry studies have been used to demonstrate that the inhibition of alpha-chymotrypsin by N-sulfonylhydroxymethylpyrrole inhibitors (10) is non-covalent. Hydroxyalkylpyrroles in which an electron-withdrawing group (acyl substituent) is introduced at the alternative C2 position have been synthesised and also shown to inactivate alpha-chymotrypsin. SAR studies on this class suggests that the incorporation of phenylalanine at C2 is favoured, however, there is little gain in introducing a hydrophobic substituent at C5.