RESUMO
Two consecutive prefractionated fractions of the Australian marine sponge extract, Pipestela candelabra, were identified to be selectively active on the human prostate cancer cells (PC3) compared to the human neonatal foreskin fibroblast non-cancer cells (NFF). Twelve secondary metabolites were isolated in which four compounds are new small peptides. Their structures were characterized by spectroscopic and chemical analysis. These compounds inhibited selectively the growth of prostate cancer cells with IC50 values in the picomolar to sub-micromolar range. Structure-activity relationship of these compounds is discussed.
Assuntos
Antineoplásicos/farmacologia , Peptídeos/farmacologia , Poríferos/metabolismo , Neoplasias da Próstata/tratamento farmacológico , Animais , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Austrália , Linhagem Celular Tumoral , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Humanos , Recém-Nascido , Concentração Inibidora 50 , Masculino , Pênis/citologia , Peptídeos/química , Peptídeos/isolamento & purificação , Neoplasias da Próstata/patologia , Análise Espectral , Relação Estrutura-AtividadeRESUMO
Inhibition of isoprenylcysteine Carboxylmethyltransferase (ICMT) is of particular interest as a potential target for the development of cancer chemotherapeutic agents. Screening for inhibitors of ICMT utilises a scintillation proximity assay (SPA) in which Biotin-S-Farnesyl-L-Cysteine (BFC) acts as a surrogate substrate. A solid-phase synthesis protocol for the preparation of BFC using 2-chlorotrityl chloride resin as a solid support has been developed to provide sufficient supply of BFC for high throughput screening (HTS) and subsequent chemistry campaigns to target inhibitors of ICMT. The BFC prepared by this method can be produced quickly on large scale and is stable when stored at -20 °C as a solid, in solution, or on the resin.
Assuntos
Biotina/química , Cisteína/química , Proteínas Metiltransferases/metabolismo , Cisteína/síntese química , Ensaios de Triagem em Larga Escala , Cinética , Proteínas Metiltransferases/química , Técnicas de Síntese em Fase Sólida , Especificidade por Substrato , Compostos de Tritil/químicaRESUMO
Two new bromotyrosine alkaloids, pseudoceralidinone A (1) and aplysamine 7 (2), along with three known compounds were isolated from the Australian sponge Pseudoceratina verrucosa. Their structures were characterized by NMR and MS data and the synthetic route. Their cytotoxicity was evaluated against cancer cell lines (HeLa and PC3) and a noncancer cell line (NFF).
Assuntos
Alcaloides/isolamento & purificação , Hidrocarbonetos Bromados/isolamento & purificação , Poríferos/química , Tiazóis/isolamento & purificação , Alcaloides/química , Alcaloides/farmacologia , Animais , Austrália , Ensaios de Seleção de Medicamentos Antitumorais , Células HeLa , Humanos , Hidrocarbonetos Bromados/química , Hidrocarbonetos Bromados/farmacologia , Masculino , Biologia Marinha , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Oxazóis , Tiazóis/química , Tiazóis/farmacologia , Tirosina/análogos & derivados , Tirosina/químicaRESUMO
Three new cyclic depsipeptides, neamphamides B (2), C (3), and D (4), were isolated from the Australian sponge Neamphius huxleyi. The planar structural characterization of these molecules was elucidated using 2D NMR experiments and ESI-FTICR-MS(n). Their configurations were determined by Marfey's method and J-based NMR analysis. These new metabolites inhibited the growth of human cell lines (A549, HeLa, LNCaP, PC3, and NFF) with IC(50) values ranging from 88 to 370 nM. However, neamphamide D causes A549 cell proliferation at subcytotoxic doses and should be treated cautiously as a cytotoxic compound.
Assuntos
Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Depsipeptídeos/isolamento & purificação , Depsipeptídeos/farmacologia , Poríferos/química , Animais , Antineoplásicos/química , Austrália , Depsipeptídeos/química , Células HeLa , Humanos , Biologia Marinha , Estrutura Molecular , Ressonância Magnética Nuclear BiomolecularRESUMO
Two of the four parameters in the 'rule of five', molecular weight and logP, which can be detected and predicted by mass spectrometry and compound retention on reversed-phase HPLC, were used as guidelines in natural product isolation. A new aporphine alkaloid, (6aR)-normecambroline (1), was isolated from the bark of Neolitsea dealbata (R. Br.) Merr. Its structure was determined on the basis of NMR, MS and CD analysis. It is the first time the absolute configuration of the roemerine-N-oxide was assigned for both roemerine-N(α)-oxide (3) and roemerine-N(ß)-oxide (4). Physico-chemical property evaluation demonstrated all alkaloids had no Lipinski violation. Compound 1 inhibited selectively against cervical cancer cells (HeLa) with an IC(50) of 4.0 µM.
Assuntos
Alcaloides/química , Aporfinas/química , Lauraceae/química , Alcaloides/isolamento & purificação , Alcaloides/toxicidade , Aporfinas/isolamento & purificação , Aporfinas/toxicidade , Austrália , Linhagem Celular Tumoral , Dicroísmo Circular , Humanos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Conformação MolecularRESUMO
Mass-directed isolation of the CH(2)Cl(2)/MeOH extract from the leaves of Cryptocarya obovata resulted in the purification of a new trypanocidal alpha-pyrone, 7',8'-dihydroobolactone (1). The chemical structure of 1 was determined by 1D/2D NMR, MS and CD data analysis. 7',8'-Dihydroobolactone was shown to inhibit Trypanosoma brucei brucei with an IC(50) of 2.8 microM.
Assuntos
Lactonas/farmacologia , Pironas/farmacologia , Tripanossomicidas/farmacologia , Linhagem Celular Tumoral , Humanos , Lactonas/química , Pironas/química , Tripanossomicidas/isolamento & purificaçãoRESUMO
Bioassay-guided fractionation of the organic extract from the marine sponge Acanthella costata resulted in the isolation of the known natural product, (-)-dibromophakellin (1). Using a fluorescence imaging plate reader (FLIPR) based assay, compound 1 was identified as displaying agonist activity against the alpha(2B) adrenoceptor, with an EC(50) of 4.2muM. Debromination and Suzuki-Miyaura coupling reactions were undertaken in order to provide structure activity data about the pyrrole ring of this marine metabolite. These synthetic studies generated the known natural product analogues, (-)-phakellin (2), and (-)-monobromophakellin (3), along with the new synthetic derivatives (-)-4-bromo-5-phenylphakellin (5) and (-)-4,5-diphenylphakellin (6). Substitution of the C-5 Br of 1 with H (2 and 3) or phenyl (5 and 6) resulted in loss of activity indicating that Br at C-5 is required for agonist activity.
Assuntos
Agonistas alfa-Adrenérgicos/isolamento & purificação , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Poríferos/química , Agonistas alfa-Adrenérgicos/farmacologia , Animais , Austrália , Linhagem Celular , Humanos , Espectrofotometria Ultravioleta , Relação Estrutura-AtividadeRESUMO
CC chemokine receptor 5 (CCR5) is a pro-inflammatory chemokine receptor that is expressed on cells of the immune system, and specializes in cell migration in response to inflammation and tissue damage. Due to its key role in cell communication and migration, this receptor is involved in various inflammatory and autoimmune diseases, in addition to HIV infection. Met-RANTES is a modified CCR5 ligand that has previously been shown to antagonize CCR5 activation and function in response to its natural ligands in vitro. In vivo, Met-RANTES is able to reduce inflammation in models of induced inflammatory and autoimmune diseases. However, due to the fact that Met-RANTES is also capable of partial agonist activity regarding receptor signaling and internalization, it is clear that Met-RANTES does not function as a conventional receptor antagonist. To further elucidate the effect of Met-RANTES on CCR5, receptor trafficking was investigated in a CHO-CCR5-GFP cell line using the Opera confocal plate reader. The internalization response of CCR5 was quantified, and showed that Met-RANTES internalized CCR5 in a slower, less potent manner than the agonists CCL3 and CCL5. Fluorescent organelle labeling and live cell imaging showed CCL3 and CCL5 caused CCR5 to traffic through sorting endosomes, recycling endosomes and the Golgi apparatus. In contrast, Met-RANTES caused CCR5 to traffic through sorting endosomes and the Golgi apparatus in a manner that was independent of recycling endosomes. As receptor trafficking impacts on cell surface expression and the ability of the receptor to respond to more ligand, this information may indicate an alternative regulation of CCR5 by Met-RANTES that allows the modified ligand to reduce inflammation through stimulation of a pro-inflammatory receptor.
Assuntos
Antagonistas dos Receptores CCR5 , Quimiocina CCL5/farmacologia , Receptores CCR5/metabolismo , Animais , Células CHO , Ceramidas/metabolismo , Quimiocina CCL3/farmacologia , Cricetinae , Cricetulus , Endossomos/efeitos dos fármacos , Endossomos/metabolismo , Complexo de Golgi/metabolismo , Humanos , Ligantes , Transporte Proteico , Receptores CCR5/agonistas , Receptores CCR5/genéticaRESUMO
Isoprenylcysteine carboxyl methyltransferase (Icmt) is enzyme target in anticancer drug discovery. An Icmt natural product high-throughput screening campaign was conducted and a hit extract from the roots of Hovea parvicalyx was identified. 2'-Methoxy-3'-prenyl-licodione and 2'-methoxy-3',3''-diprenyl-licodione, two prenylated beta-hydroxychalcone compounds, together with the known flavanone (S)-glabrol, were isolated and identified as bioactive constituents. Their structures were determined largely by 1D and 2D NMR spectroscopy.
Assuntos
Antineoplásicos/química , Inibidores Enzimáticos/química , Fabaceae/química , Proteínas Metiltransferases/antagonistas & inibidores , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Proteínas Metiltransferases/metabolismoRESUMO
A new natural product, lysianadioic acid, was isolated from the plant Lysiana subfalcata as a carboxypeptidase B (CPB) inhibitor. It is a potent inhibitor of CPB with an IC(50) of 0.36 microM. This is the first known example of a small molecule CPB inhibitor isolated from plant origin. Its structure was determined by NMR spectroscopy.
Assuntos
Arginina/análogos & derivados , Carboxipeptidase B/antagonistas & inibidores , Guanidinas/química , Guanidinas/farmacologia , Loranthaceae/química , Inibidores de Proteases/química , Inibidores de Proteases/farmacologia , Succinatos/química , Succinatos/farmacologia , Guanidinas/isolamento & purificação , Ressonância Magnética Nuclear Biomolecular , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Inibidores de Proteases/isolamento & purificação , Succinatos/isolamento & purificaçãoRESUMO
High-throughput screening of a plant and marine invertebrate extract library to find natural products that inhibit the malarial parasite enzyme target hemoglobinase II led to the isolation of two new active prenylated chalcones, bipinnatones A (1) and B (2), from aerial parts of the Queensland shrub Boronia bipinnata. Their structures were assigned from interpretation of 2D NMR and high-resolution ESIMS data. Compounds 1 and 2 inhibited hemoglobinase II with IC 50 values of 64 and 52 microM, respectively.
Assuntos
Chalconas/isolamento & purificação , Inibidores Enzimáticos/isolamento & purificação , Plasmodium falciparum/enzimologia , Rutaceae/química , Animais , Chalconas/química , Chalconas/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Estrutura Molecular , Prenilação , Análise EspectralRESUMO
High-throughput screening of a plant and marine invertebrate extract library to find natural products that down-regulate expression of pro-inflammatory genes associated with the glucocorticoid receptor ligand complex led to the identification of bioactive CH2Cl 2 extracts from stems and leaves of the Queensland tree Ochrosia moorei. Bioassay-guided purification of the stem extract enabled the isolation of four alkaloids including two new compounds, ochrosamines A (1) and B (2), and the known compounds ellipticine (3) and 9-methoxyellipticine (4). The leaf extract also afforded 3 and 4 as well as apparicine (5) and desoxycordifoline (6). The structures of the two new compounds were assigned from interpretation of 2D NMR and high-resolution ESIMS data. Ellipticine and 9-methoxyellipticine were the most active components, and both displayed IC 50 values of 90 microM. Apparicine and desoxycordifoline were only very weakly active, and ochrosamines A and B were inactive.
Assuntos
Alcaloides/isolamento & purificação , Ochrosia/química , Árvores/química , Alcaloides/química , Alcaloides/farmacologia , Austrália , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Folhas de Planta/química , Caules de Planta/químicaRESUMO
The anticancer target isoprenylcysteine carboxyl methyltransferase (Icmt) was the focus of a natural product high-throughput screening campaign. The Australian marine sponge Pseudoceratina sp. yielded aplysamine 6, a new bromotyrosine derivative with an alpha,beta-unsaturated amide linkage, as the bioactive constituent. Its structure was determined by 1D and 2D NMR spectroscopy.
Assuntos
Poríferos/química , Proteínas Metiltransferases/antagonistas & inibidores , Tirosina/análogos & derivados , Animais , Austrália , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Tirosina/química , Tirosina/isolamento & purificação , Tirosina/farmacologiaRESUMO
Isoprenylcysteine methyltransferase (Icmt) catalyzes the carboxyl methylation of oncogenic proteins in the final step of a series of post-translational modifications. The inhibition of Icmt provides an attractive and novel anticancer target. A natural product high-throughput screening campaign was conducted to discover inhibitors of Icmt. The Australian marine sponge, Pseudoceratina sp., yielded spermatinamine, a novel alkaloid with a bromotyrosyl-spermine-bromotyrosyl sequence, as the bioactive constituent. Its structure was determined by 1D and 2D NMR spectroscopy. Spermatinamine is the first natural product inhibitor of Icmt.
Assuntos
Antineoplásicos/toxicidade , Produtos Biológicos/química , Produtos Biológicos/toxicidade , Neoplasias/enzimologia , Proteínas Metiltransferases/antagonistas & inibidores , Espermina/análogos & derivados , Tirosina/análogos & derivados , Antineoplásicos/química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/toxicidade , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Neoplasias/patologia , Proteínas Metiltransferases/metabolismo , Espermina/química , Espermina/toxicidade , Tirosina/química , Tirosina/toxicidadeRESUMO
Four imidazo-azolo-imidazole alkaloids, axinellamines A-D, have been isolated from an Australian marine sponge, Axinella sp. (order: Halichondrida: family: Axinellidae). These compounds contain a unique perhydrocyclopenta-imidazo-azolo-imidazole carbon skeleton. Three of these compounds had bactericidal activity against Helicobacter pylori at 1000 &mgr;M.
RESUMO
A novel vanillic acid derivative (1) and its sulfate adduct (2) were isolated from a green algae, Cladophora socialis. The structures of 1 and 2 were elucidated from NMR and HRESIMS experiments. Both compounds showed potent inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), an enzyme involved in the regulation of insulin cell signaling. Compounds 1 and 2 had IC50 values of 3.7 and 1.7 microM, respectively.