RESUMO
This study identified the isoindolone ring as a scaffold for novel agents against Trypanosoma brucei rhodesiense and explored the structure-activity relationships of various aromatic ring substitutions. The compounds were evaluated in an integrated inâ vitro screen. Eight compounds exhibited selective activity against T. b. rhodesiense (IC50 <2.2â µm) with no detectable side activity against T. cruzi and Leishmania infantum. Compound 20 showed low nanomolar potency against T. b. rhodesiense (IC50 =40â nm) and no toxicity against MRC-5 and PMM cell lines and may be regarded as a new lead template for agents against T. b. rhodesiense. The isoindolone-based compounds have the potential to progress into lead optimization in view of their highly selective inâ vitro potency, absence of cytotoxicity and acceptable metabolic stability. However, the solubility of the compounds represents a limiting factor that should be addressed to improve the physicochemical properties that are required to proceed further in the development of inâ vivo-active derivatives.
Assuntos
Isoindóis/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma brucei rhodesiense/efeitos dos fármacos , Animais , Linhagem Celular , Estabilidade de Medicamentos , Feminino , Humanos , Isoindóis/síntese química , Isoindóis/metabolismo , Isoindóis/toxicidade , Camundongos , Microssomos Hepáticos/metabolismo , Estrutura Molecular , Testes de Sensibilidade Parasitária , Solubilidade , Relação Estrutura-Atividade , Tripanossomicidas/síntese química , Tripanossomicidas/metabolismo , Tripanossomicidas/toxicidadeRESUMO
A library of 89 synthetic benzenesulfonyl derivatives of heterocycles with drug-like properties was assayed for in vitro antiparasitic activity and the results were added to our previously reported derivatives for a comprehensive SAR evaluation. Four compounds showed an IC50 between 0.25 and 3µM against Leishmania donovani and low cytotoxicity. Compound G{16} (1-(2,3,5,6-tetramethylphenylsulfonyl)-2-methylindoline), was particularly interesting with an IC50 similar to the reference drug miltefosine. Seven compounds showed an IC50 below 6µM against Trypanosoma cruzi, and three of them (E{3}, E{9} and G{3}) were identified as lead scaffolds for further optimization based on their activity-toxicity profile. Two promising structures (B{15} and G{15}) showed moderate inhibitory activity against Plasmodium falciparum. In general, the presence of a benzenesulfonyl moiety improves the antiparasitic activity of the heterocycles included in this study (with the exception of Trypanosoma brucei rhodesiense), validating the criteria used in the selection of the privileged structures and diversification used to generate this library. SAR analysis showed that the presence of lipophilic and electron withdrawing groups were favorable for the antiparasitic activity.
Assuntos
Antiparasitários/farmacologia , Compostos de Benzil/farmacologia , Compostos Heterocíclicos/farmacologia , Mioblastos/efeitos dos fármacos , Animais , Antiparasitários/síntese química , Antiparasitários/química , Compostos de Benzil/síntese química , Compostos de Benzil/química , Relação Dose-Resposta a Droga , Compostos Heterocíclicos/síntese química , Compostos Heterocíclicos/química , Leishmania donovani/efeitos dos fármacos , Estrutura Molecular , Testes de Sensibilidade Parasitária , Plasmodium falciparum/efeitos dos fármacos , Ratos , Relação Estrutura-Atividade , Trypanosoma brucei rhodesiense/efeitos dos fármacos , Trypanosoma cruzi/efeitos dos fármacosRESUMO
A series of 14 (E)-cinnamic N-acylhydrazone derivatives, designed through molecular hybridization between the (E)-1-(benzo[d][1,3]dioxol-5-yl)-3-(4-bromophenyl)prop-2-en-1-one and (E)-3-hydroxy-N'-((2-hydroxynaphthalen-1-yl)methylene)-7-methoxy-2-naphthohydrazide, were tested for in vitro antiparasitic activity upon axenic amastigote forms of Leishmania donovani and bloodstream forms of Trypamosoma brucei rhodesiense. The derivative (2E)-3-(4-hydroxy-3-methoxy-5-nitrophenyl)-N'-[(1E)-phenylmethylene]acrylohydrazide showed moderate antileishmanial activity (IC50 = 6.27 µM) when compared to miltefosine, the reference drug (IC50 = 0.348 µM). However, the elected compound showed an excellent selectivity index; in one case it was not cytotoxic against mammalian L-6 cells. The most active antitrypanosomal compound, the derivative (E)-N'-(3,4-dihydroxybenzylidene)cinnamohydrazide (IC50 = 1.93 µM), was cytotoxic against mammalian L-6 cells.
Assuntos
Antiprotozoários/química , Antiprotozoários/farmacologia , Cinamatos/química , Hidrazonas/química , Hidrazonas/farmacologia , Leishmania donovani/efeitos dos fármacos , Estrutura Molecular , Testes de Sensibilidade Parasitária , Trypanosoma brucei rhodesiense/efeitos dos fármacosRESUMO
BACKGROUND: The neglected human diseases caused by trypanosomatids are currently treated with toxic therapy with limited efficacy. In search for novel anti-trypanosomatid agents, we showed previously that the Crotalus viridis viridis (Cvv) snake venom was active against infective forms of Trypanosoma cruzi. Here, we describe the purification of crovirin, a cysteine-rich secretory protein (CRISP) from Cvv venom with promising activity against trypanosomes and Leishmania. METHODOLOGY/PRINCIPAL FINDINGS: Crude venom extract was loaded onto a reverse phase analytical (C8) column using a high performance liquid chromatographer. A linear gradient of water/acetonitrile with 0.1% trifluoroacetic acid was used. The peak containing the isolated protein (confirmed by SDS-PAGE and mass spectrometry) was collected and its protein content was measured. T. cruzi trypomastigotes and amastigotes, L. amazonensis promastigotes and amastigotes and T. brucei rhodesiense procyclic and bloodstream trypomastigotes were challenged with crovirin, whose toxicity was tested against LLC-MK2 cells, peritoneal macrophages and isolated murine extensor digitorum longus muscle. We purified a single protein from Cvv venom corresponding, according to Nano-LC MS/MS sequencing, to a CRISP of 24,893.64 Da, henceforth referred to as crovirin. Human infective trypanosomatid forms, including intracellular amastigotes, were sensitive to crovirin, with low IC50 or LD50 values (1.10-2.38 µg/ml). A considerably higher concentration (20 µg/ml) of crovirin was required to elicit only limited toxicity on mammalian cells. CONCLUSIONS: This is the first report of CRISP anti-protozoal activity, and suggests that other members of this family might have potential as drugs or drug leads for the development of novel agents against trypanosomatid-borne neglected diseases.
Assuntos
Venenos de Crotalídeos/farmacologia , Leishmania mexicana/efeitos dos fármacos , Proteínas de Répteis/farmacologia , Trypanosoma brucei rhodesiense/efeitos dos fármacos , Trypanosoma cruzi/efeitos dos fármacos , Animais , Antiprotozoários/farmacologia , Proteínas de Transporte , Doença de Chagas/tratamento farmacológico , Crotalus/metabolismo , Citoplasma , Eletroforese em Gel de Poliacrilamida , Humanos , Proteínas com Domínio LIM , Leishmania , Leishmania mexicana/crescimento & desenvolvimento , Camundongos , Doenças Negligenciadas/tratamento farmacológico , Doenças Negligenciadas/parasitologia , Testes de Sensibilidade Parasitária , Espectrometria de Massas em Tandem , Trypanosoma brucei rhodesiense/crescimento & desenvolvimento , Trypanosoma cruzi/crescimento & desenvolvimentoRESUMO
2-Alkynoic fatty acids display antimycobacterial, antifungal, and pesticidal activities but their antiprotozoal activity has received little attention. In this work we synthesized the 2-octadecynoic acid (2-ODA), 2-hexadecynoic acid (2-HDA), and 2-tetradecynoic acid (2-TDA) and show that 2-ODA is the best inhibitor of the Leishmania donovani DNA topoisomerase IB enzyme (LdTopIB) with an EC(50)=5.3±0.7µM. The potency of LdTopIB inhibition follows the trend 2-ODA>2-HDA>2-TDA, indicating that the effectiveness of inhibition depends on the fatty acid carbon chain length. All of the studied 2-alkynoic fatty acids were less potent inhibitors of the human topoisomerase IB enzyme (hTopIB) as compared to LdTopIB. 2-ODA also displayed in vitro activity against Leishmania donovani (IC(50)=11.0µM), but it was less effective against other protozoa, Trypanosoma cruzi (IC(50)=48.1µM) and Trypanosoma brucei rhodesiense (IC(50)=64.5µM). The antiprotozoal activity of the 2-alkynoic fatty acids, in general, followed the trend 2-ODA>2-HDA>2-TDA. The experimental information gathered so far indicates that 2-ODA is a promising antileishmanial compound.
Assuntos
Alcinos/farmacologia , Antiprotozoários/farmacologia , DNA Topoisomerases Tipo I/metabolismo , Ácidos Graxos Insaturados/farmacologia , Leishmania donovani/enzimologia , Inibidores da Topoisomerase I/farmacologia , Alcinos/síntese química , Alcinos/química , Animais , Antiprotozoários/síntese química , Antiprotozoários/química , Linhagem Celular , Relação Dose-Resposta a Droga , Ácidos Graxos Insaturados/síntese química , Ácidos Graxos Insaturados/química , Humanos , Leishmania donovani/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Estrutura Molecular , Testes de Sensibilidade Parasitária , Ratos , Relação Estrutura-Atividade , Inibidores da Topoisomerase I/síntese química , Inibidores da Topoisomerase I/química , Trypanosoma brucei rhodesiense/efeitos dos fármacos , Trypanosoma cruzi/efeitos dos fármacosRESUMO
In a survey of plants from Ecuador with antiprotozoal activity, Cupania cinerea was found to show significant in vitro activity against the Plasmodium falciparum K1 strain and Trypanosoma brucei rhodesiense. Subsequently, activity-guided isolation of the n-hexane and dichloromethane extracts from the bark of C. cinerea afforded two diterpene glycosides (1 and 2), named cupacinoside and 6'-de-O-acetylcupacinoside, and a lactonized triterpene bearing an oxepin moiety named cupacinoxepin (3), together with the known compounds scopoletin (4), caryophyllene oxide (5), two bisabolane sesquiterpenes (6 and 7), lichexanthone (8), gustastatin (9), lupenone (10), betulone (11), 17ß,21ß-epoxyhopan-3-one (12), taraxerol (13), and taraxerone (14). For compound 3, X-ray crystallography was employed to elucidate the relative configuration. For cupacinosides (1) and (2) and cupacinoxepin (3), in vitro activities against the P. falciparum K1 strain (IC(50)1, 1.3; 2, 1.8; and 3, 8.7 µM) and T. b. rhodesiense (IC(50)1, 4.5; 2, 15.8; and 3, 71.6 µM) were found. Cytotoxicity toward L-6 cells is discussed for all the compounds isolated.
Assuntos
Antiprotozoários/isolamento & purificação , Antiprotozoários/farmacologia , Diterpenos/isolamento & purificação , Diterpenos/farmacologia , Glicosídeos/isolamento & purificação , Glicosídeos/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Sapindaceae/química , Triterpenos/isolamento & purificação , Triterpenos/farmacologia , Trypanosoma brucei rhodesiense/efeitos dos fármacos , Animais , Antiprotozoários/química , Células Cultivadas , Cristalografia por Raios X , Diterpenos/química , Equador , Glicosídeos/química , Hexanos , Estrutura Molecular , Testes de Sensibilidade Parasitária , Sesquiterpenos Policíclicos , Ratos , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , Triterpenos/químicaRESUMO
The chemical composition of the Caribbean sponge Pandaros acanthifolium was reinvestigated and led to the isolation of 12 new steroidal glycosides, namely, pandarosides E-J (1-6) and their methyl esters (7-12). Their structures were determined on the basis of extensive spectroscopic analyses, including two-dimensional NMR and HRESIMS data. Like the previously isolated pandarosides A-D (13-16), the new compounds 1-12 share an unusual oxidized D-ring and a cis C/D ring junction. The absolute configurations of the aglycones were assigned by interpretation of CD spectra, whereas the absolute configurations of the monosaccharide units were determined by chiral GC analyses of the acid methanolysates. The majority of the metabolites showed in vitro activity against three or four parasitic protozoa. Particularly active were the compounds 3 (pandaroside G) and its methyl ester (9), which potently inhibited the growth of Trypanosoma brucei rhodesiense (IC(50) values 0.78 and 0.038 microM, respectively) and Leishmania donovani (IC(50)'s 1.3 and 0.051 microM, respectively).
Assuntos
Antiprotozoários/isolamento & purificação , Antiprotozoários/farmacologia , Poríferos/química , Saponinas/isolamento & purificação , Saponinas/farmacologia , Esteroides/isolamento & purificação , Esteroides/farmacologia , Animais , Antiprotozoários/química , Leishmania donovani/efeitos dos fármacos , Biologia Marinha , Ressonância Magnética Nuclear Biomolecular , Oceanos e Mares , Plasmodium falciparum/efeitos dos fármacos , Saponinas/química , Esteroides/química , Trypanosoma brucei rhodesiense/efeitos dos fármacos , Trypanosoma cruzi/efeitos dos fármacosRESUMO
High-speed counter-current chromatography (HSCCC) with a two-phase solvent system (hexane-ethanol-acetonitrile-water 10:8:1:1, v/v) was applied to examine the leaves of Hortia oreadica, which afforded the known limonoid guyanin (1), the alkaloids rutaecarpin (2) and dictamnine (6), the dihydrocinnamic acid derivatives methyl 5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran-6-propanoate (3), 5,8-dimethoxy-2,2-dimethyl-2H-1-benzopyran-6-propanoic acid (4), together with the new E-3,4-dimethoxy-alpha(3-hydroxy-4-carbomethoxyphenyl)cinnamic acid (5). The recovery of compounds 1-6 was determined by comparison with LC-atmospheric pressure chemical ionization MS/MS data: 66.2%, 93.1%, 102.5%, 101.2%, 99.0% and 84.9%, respectively. Compound 3 showed IC(50) of 23.6microM against Plasmodium falciparum and 15.6microM against Trypanosoma brucei rhodesienses and was not toxic to KB cells (IC(50)>100microM).
Assuntos
Distribuição Contracorrente/métodos , Extratos Vegetais/química , Folhas de Planta/química , Rutaceae/química , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cinamatos/isolamento & purificação , Cinamatos/farmacologia , Humanos , Alcaloides Indólicos/isolamento & purificação , Alcaloides Indólicos/farmacologia , Concentração Inibidora 50 , Limoninas/isolamento & purificação , Limoninas/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Quinazolinas/isolamento & purificação , Quinazolinas/farmacologia , Quinolinas/isolamento & purificação , Quinolinas/farmacologia , Rutaceae/metabolismo , Trypanosoma brucei rhodesiense/efeitos dos fármacosRESUMO
OBJECTIVES: The known anti-protozoal activity of flavonoids has stimulated the testing of other derivatives from natural and synthetic sources. METHODS: As part of our efforts to find potential lead compounds, a number of flavonoids isolated from Neoraputia paraensis, N. magnifica, Murraya paniculata, (Rutaceae), Lonchocarpus montanus, L. latifolius, L. subglaucescens, L. atropurpureus, L. campestris, Deguelia hatschbachii (Leguminosae), dibenzoylmethanes from L. subglaucescens and synthetic analogues were tested for in-vitro activity against chloroquine-sensitive Plasmodium falciparum and Trypanosoma brucei rhodesiense bloodstream form trypomastigotes. An assay with KB cells has been developed in order to compare in-vitro cytotoxicity of flavonoids with a selective action on the parasites. KEY FINDINGS: Thirteen of the compounds tested had IC50 values ranging from 4.6 to 9.9 microm against T. brucei rhodesiense. In contrast, a small number of compounds showed significant activity against P. falciparum; seven of those tested had IC50 values ranging from 2.7 to 9.5 microm. Among the flavones only one had IC50 < 10 microm (7.6 microm), whereas against T. brucei rhodesiense seven had IC50 < 10 microm. Synthetic dibenzoylmethanes were the most active in terms of number (five) of compounds and the IC50 values (2.7-9.5 microm) against P. falciparum. CONCLUSIONS: Dibenzoylmethanes represent a novel class of compounds tested for the first time as antimalarial and trypanocidal agents.
Assuntos
Antimaláricos/uso terapêutico , Descoberta de Drogas , Flavonoides/química , Tripanossomicidas/uso terapêutico , Animais , Antimaláricos/química , Antimaláricos/isolamento & purificação , Antimaláricos/toxicidade , Chalconas/química , Chalconas/uso terapêutico , Chalconas/toxicidade , Calônios/química , Calônios/uso terapêutico , Calônios/toxicidade , Química Farmacêutica/métodos , Química Farmacêutica/tendências , Fabaceae/química , Flavonoides/isolamento & purificação , Flavonoides/uso terapêutico , Humanos , Concentração Inibidora 50 , Células KB , Estrutura Molecular , Plasmodium falciparum/efeitos dos fármacos , Rutaceae/química , Tripanossomicidas/química , Tripanossomicidas/isolamento & purificação , Tripanossomicidas/toxicidade , Trypanosoma brucei rhodesiense/efeitos dos fármacosRESUMO
The effect of several alkyl-linked bis tetrahydro-(2H)-1,3,5-thiadiazine-2-thione (bis-THTT) on Leishmania donovani, Trypanosoma brucei rhodesiense, and Plasmodium falciparum is reported. Most of the compounds exhibited a potent activity against the three parasitic strains but the best in vitro activity profiles were found against T. b. rhodesiense with IC(50) values ranging between 0.3 and 4 microM for the most active compounds.