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| Registros recuperados: 13 | |
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| Regalado, E.L.; Mendiola, J.; Laguna, A.; Nogueiras, C.; Thomas, O.P.. |
| A method involving flash chromatography, semi-preparative phenylhexyl RP HPLC-DAD-ELSD combined with analytic polar-RP HPLC-DAD, was applied to separate and purify six highly nitrogenated bases and a bicyclic amidine alkaloid, the major components of the marine sponge Niphates digitalis. Their structures were identified as 1,8-diazabicyclo[5.4.0]undec-7- ene (1), deoxycytidine (2), phenylalanine (3), adenosine (4), deoxyguanosine (5), adenine (6) and thymidine (7) on the basis of spectroscopic data analyses. This is the first report of these compounds in a marine sponge belonging to the Niphates genus and the first evidence of the presence of 1 from a natural source. |
| Tipo: Journal Contribution |
Palavras-chave: Sponges; Cytotoxicity; Cytotoxicity; Sponges; Http://aims.fao.org/aos/agrovoc/c_34251; Http://aims.fao.org/aos/agrovoc/c_7321. |
| Ano: 2010 |
URL: http://hdl.handle.net/1834/3860 |
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| Nogueiras, C.; Spengler, I.; Guerra, J.O.; Ortiz, Y.; Torres, S.; García, T.H.; Romeu, C.R.; Regalado, E.L.; González, T.A.; Perera, W.H.; Lacret, R.. |
| Interest in natural products as a source for innovation in drug discovery and agrochemicals is still growing worldwide. Natural products, whose immense diversity has been appreciated for many years, may become in a rich source of novel chemical structures. Our country is a rich source of both biological and chemical diversity which may be useful as a source of novel chemical structures. Even when natural products have been used as medicinal agents for many years in Cuba, their use as agrochemicals are still limited. Thus, the present review focuses on recent advances in the studies on natural products performed by the “Centro de Estudios de Productos Naturales, CEPN” during the past ten years, highlighting on those with potential use as biomedical... |
| Tipo: Journal Contribution |
Palavras-chave: Products; Chemical compounds; Bioactive compounds; Products; Chemical compounds; Http://aims.fao.org/aos/agrovoc/c_6211; Http://aims.fao.org/aos/agrovoc/c_49870. |
| Ano: 2010 |
URL: http://hdl.handle.net/1834/3986 |
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| Regalado, E.L.; Rodríguez, M.; Menéndez, R.; Concepción, A.A.; Nogueiras, C.; Laguna, A.; Rodríguez, A.A.; Williams, D.E.; Lenzo-Luaces, P.; Valdés, O.; Hernandez, Y.. |
| Daily topical application of the aqueous ethanolic extract of the marine sea grass, Thalassia testudinum, on mice skin exposed to UVB radiation resulted in a dose dependent recovery of the skin macroscopic alterations over a 6-day period. Maximal effect (90%) occurred at a dose of 240 μg/cm2, with no additional effects at higher doses. Bioassay-guided fractionation of the plant extract resulted in the isolation of thalassiolin B (1). Topical application of 1 (240 μg/cm2) markedly reduces skin UVB-induced damage. In addition, thalassiolin B scavenged 2,2-diphenyl-2-picrylhydrazyl radical with an EC50=100 μg/ml. These results suggest that thalassiolin B is responsible for the skin regenerating effects of the crude extract of T. testudinum |
| Tipo: Journal Contribution |
Palavras-chave: Chemistry; Pharmacology; Chemistry; Pharmacology; Http://aims.fao.org/aos/agrovoc/c_1522; Http://aims.fao.org/aos/agrovoc/c_5760. |
| Ano: 2009 |
URL: http://hdl.handle.net/1834/3865 |
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| Hernández, Y.; Laguna, A.; Fernández, M.D.; Valdés, O.; Regalado, E.L.. |
| Ha sido demostrado, por otros autores, que el alga Ulva fasciata Delile posee una actividad antioxidante promisoria y en el presente trabajo evaluamos si la actividad antioxidante de muestras de esta alga puede ser influenciada por la adsorción de metales, pesados y otros por parte del alga. U. fasciata fue colectada en tres zonas de las costas de la Ciudad de la Habana que presentan diferentes niveles de eutrofización: 1) la desembocadura del Río Quibú, un río que atraviesa una importante zona industrial de la capital cubana y en la cual la concentración de metales acumulados por el alga fue mayor; 2) la zona del Malecón habanero, que recibe la contaminación de la bahía de la Habana y del Río Almendares pero no de forma directa, donde presentó valores... |
| Tipo: Journal Contribution |
Palavras-chave: Algae; Marine environment; Heavy metals; Marine environment; Heavy metals; Algae; Http://aims.fao.org/aos/agrovoc/c_4610; Http://aims.fao.org/aos/agrovoc/c_2223; Http://aims.fao.org/aos/agrovoc/c_258. |
| Ano: 2008 |
URL: http://hdl.handle.net/1834/2919 |
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| Regalado, E.L.; Laguna, A.; Torres, M.; Sabatier, J.D.; Hernández, M.; Ferrer, A.E.; Nogueiras, C.. |
| Hydrogen peroxide bleaching of sodium alginate from seaweeds oh the Sargassum genus was studied. The influence of H2O2 concentration (percentage of H2O2 on a dry weight alginate basis, w/w) and NaOH/H2O2 ratio (% NaOH/% H2O2, both referred to a dry weight alginate basis, w/w) on the molecular weight, color removal and content of Fe3+ ions of bleached alginate samples was investigated by UV and IR spectroscopies, colorimetric determination of Fe3+ ions and vapor pressure osmometry. Higher yield, purity and molecular weight of alginate were obtained using 3% (or less) of hydrogen peroxide and a NaOH/H2O2 ratio of 1.2 for bleaching. |
| Tipo: Journal Contribution |
Palavras-chave: Bleaching; Bleaching; Http://aims.fao.org/aos/agrovoc/c_953. |
| Ano: 2007 |
URL: http://hdl.handle.net/1834/3855 |
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| Regalado, E.L.; Laguna, A.; Martínez, J.R.. |
| Las esponjas marinas (Porifera) han atraído la atención de un gran número de científicos alrededor del mundo. Estos animales y sus simbiontes utilizan mecanismos de defensa química, basados en la producción de compuestos biologicamente activos que utlizan para protegerse de posibles depredadores. Son considerados una mina de oro para los químicos y se han descubierto más de 6000 estructuras novedosas, muchas de ellas con enormes aplicaciones biomédicas, fundamentalmente contra el cáncer, pero también contra diversas bacterias, virus y otras enfermedades. Algunos de los fármacos derivados de esponjas se encuentran disponibles en el mercado, tal es el caso Ara-A (antiviral) y de la Ara-C (antitumoral), pero existen diversos compuestos bioactivos en... |
| Tipo: Journal Contribution |
Palavras-chave: Sponges; Chemical compounds; Bioactive compounds; Chemical compounds; Sponges; Http://aims.fao.org/aos/agrovoc/c_49870; Http://aims.fao.org/aos/agrovoc/c_7321. |
| Ano: 2010 |
URL: http://hdl.handle.net/1834/4039 |
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| Regalado, E.L.; Laguna, A.; Martínez, J.R.. |
| Marine sponges (Porifera) have drawn the attention from a broad number of researchers all over the world. These animals and their simbionts are specialized in chemical warfare, producing biologically active chemical substances as an effective defense against predators. They have been considered a goldmine to chemists, from which have been discovered more than 6000 novel structures; many of them, with enormous biomedical applications, mainly against cancer, but also against bacteria, viruses and other diseases. Some of the sponge-derived drugs are available in the market, such as: Ara-A (antiviral) and Ara-C (anticancer), but there are diverse bioactive compounds under clinical trials. In Cuba, the researches related to the isolation of compounds from... |
| Tipo: Journal Contribution |
Palavras-chave: Sponges; Organic compounds; Antiparasitic agents. |
| Ano: 2010 |
URL: http://hdl.handle.net/1834/4129 |
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| Cachet, N.; Regalado, E.L.; Genta-Jouve, G.; Mehiri, M.; Amade, P.; Thomas, O.P.. |
| The chemical composition of the Caribbean sponge Pandaros sp. was investigated and led to the isolation of seven new steroidal glycosides namely pandarosides A-D (1, 3, 4 and 6) along with the three methyl esters of pandarosides A, C, and D (2, 5 and 7). Their structures were characterized as 3β-[β-glucopyranosyl-(1→2)-β-glucopyranosyloxyuronic acid]-16-hydroxy- 5α,14β-poriferast-16-ene-15,23-dione (1) and its methyl ester (2), 3β-[β- glucopyranosyloxyuronic acid]-16-hydroxy-5α,14β-poriferast-16-ene-15,23-dione (3), 3β-[β- glucopyranosyl-(1→2)-β-glucopyranosyloxyuronic acid]-16-hydroxy-5α,14β-cholest-16-ene- 15,23-dione (4) and its methyl ester (5), 3β-(β-glucopyranosyloxyuronic acid)-16-hydroxy- 5α,14β-cholest-16-ene-15,23-dione (6) and its methyl ester... |
| Tipo: Journal Contribution |
Palavras-chave: Sponges; Sponges; Http://aims.fao.org/aos/agrovoc/c_7321. |
| Ano: 2009 |
URL: http://hdl.handle.net/1834/3859 |
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| Regalado, E.L.; Laguna, A.; Mendiola, J.; Thomas, O.P.; Nogueiras, C.. |
| Bioguided fractionation of Agelas cerebrum crude extract resulted in isolation of four bromopyrrole and four bromopyrrole aminoimidazole alkaloids, identified as 5-bromopyrrole-2-carboxylic acid (1), 4-bromopyrrole-2-carboxylic acid (2), 3,4-bromopyrrole-2-carboxylic acid (3), 4,5-bromopyrrole-2-carboxylic acid (4), oroidin (5), bromoageliferin (6), dibromoageliferin (7) and dibromosceptrin (8) on the basis of spectroscopic data analyses (UV, IR, HRMS, 1D and 2D NMR) and comparison with literature data. This is the first report of compounds 2 and 3 in a marine sponge belonging to the Agelas genus and the first evidence of the presence of 1 from a natural source. |
| Tipo: Journal Contribution |
Palavras-chave: Alkaloids; Sponges; Chemistry; Chemistry; Alkaloids; Sponges; Http://aims.fao.org/aos/agrovoc/c_1522; Http://aims.fao.org/aos/agrovoc/c_269; Http://aims.fao.org/aos/agrovoc/c_7321. |
| Ano: 2010 |
URL: http://hdl.handle.net/1834/3862 |
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| Regalado, E.L.; Tasdemir, D.; Kaiser, M.; Cachet, N.; Amade, P.; Thomas, O.P.. |
| 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... |
| Tipo: Journal Contribution |
Palavras-chave: Sponges; Sponges; Http://aims.fao.org/aos/agrovoc/c_7321. |
| Ano: 2010 |
URL: http://hdl.handle.net/1834/3863 |
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| Cachet, N.; Genta-Jouve, G.; Regalado, E.L.; Mokrini, R.; Amade, P.; Culioli, G.; Thomas, O.P.. |
| Five new hydantoin alkaloids, named parazoanthines A-E (1-5), were isolated as the major constituents of the Mediterranean sea anemone Parazoanthus axinellae. Their structural elucidation was achieved through NMR spectroscopic and mass spectrometric analyses. The absolute configuration of the chiral compounds 1 and 4 was determined by comparison between experimental and TDDFT calculated CD spectra. The configuration of the trisubstituted double bond of 2, 3, and 5 was deduced from the 3JH6-C4 coupling constant value. This family of alkaloids represents the first example of natural 3,5- disubstituted hydantoins which do not exhibit a methyl at N-3. All compounds were tested for their natural toxicity (Microtox® assay) and parazoanthine C (3) exhibited the... |
| Tipo: Journal Contribution |
Palavras-chave: Alkaloids; Alkaloids; Http://aims.fao.org/aos/agrovoc/c_269. |
| Ano: 2009 |
URL: http://hdl.handle.net/1834/3864 |
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| Regalado, E.L.; Jiménez-Romero, C.; Genta-Jouve, G.; Tasdemir, D.; Amade, P.; Nogueiras, C.; Thomas, O.P.. |
| Seven novel steroid glycosides, acanthifoliosides A-F (1-6) and the methyl ester of 6 (7), were isolated from the marine sponge Pandaros acanthifolium as minor components. Acanthifoliosides are characterized by a rare C-15 and C-16 oxidized D ring which was previously found in saponins produced by starfishes. Very uncommon is the presence of additional sugar residues at C-15 or C-16. Their structures were determined on the basis of extensive spectroscopic analyses, including two-dimensional NMR and HRESIMS data. The absolute configurations of the aglycones were assigned by comparison between experimental and TDDFT calculated CD spectra of 1, whereas the absolute configurations of the monosaccharide units were determined by chiral GC analyses of the acid... |
| Tipo: Journal Contribution |
Palavras-chave: Sponges; Sponges; Http://aims.fao.org/aos/agrovoc/c_7321. |
| Ano: 2011 |
URL: http://hdl.handle.net/1834/3866 |
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| Registros recuperados: 13 | |
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