RESUMO
Based on the chemical structure and the known chemical synthesis of the marine sponge alkaloid ageladine A, we synthesized the ageladine A-derivative 4-(naphthalene-2-yl)-1H-imidazo[4,5-c]pyridine trifluoroacetate (LysoGlow84). The two-step synthesis started with the Pictet-Spengler reaction of histamine and naphthalene-2-carbaldehyde to a tetrahydropyridine intermediate, which was dehydrogenated with activated manganese (IV) oxide to LysoGlow84. Structure and purity of the synthesized LysoGlow84 were confirmed by NMR spectroscopy and mass spectrometry. The fluorescence intensity emitted by LysoGlow84 depended strongly on the pH of the solvent with highest fluorescence intensity recorded at pH 4. The fluorescence maximum (at 315 nm excitation) was observed at 440 nm. Biocompatibility of LysoGlow84 was investigated using cultured rat brain astrocytes and the marine flatworm Macrostomum lignano. Exposure of the astrocytes for up to 6 h to micromolar concentrations of LysoGlow84 did not compromise cell viability, as demonstrated by several viability assays, but revealed a promising property of this compound for staining of cellular vesicles. Conventional fluorescence microscopy as well as confocal scanning microscopy of LysoGlow84-treated astrocytes revealed co-localization of LysoGlow84 fluorescence with that of LysoTracker® Red DND-99. LysoGlow84 stained unclear structures in Macrostomum lignano, which were identified as lysosomes by co-staining with LysoTracker. Strong fluorescence staining by LysoGlow84 was further observed around the worms' anterior gut and the female genital pore which were not counterstained by LysoTracker Red. Thus, LysoGlow84 is a new promising dye that stains lysosomes and other acidic compartments in cultured cells and in worms.
Assuntos
Encéfalo/efeitos dos fármacos , Encéfalo/ultraestrutura , Corantes Fluorescentes/síntese química , Lisossomos/efeitos dos fármacos , Platelmintos/ultraestrutura , Pirróis/síntese química , Animais , Astrócitos/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Corantes , Indicadores e Reagentes , Espectrometria de Massas , Teste de Materiais , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Ratos , Ratos WistarRESUMO
A novel lumazine peptide, penilumamide (1), was isolated from the fermentation broth of a marine-derived fungal strain, identified as Penicillium sp. (strain CNL-338) and the structure of the new metabolite was determined by analysis of ESI-TOF MS data combined with 1D and 2D NMR experiments.
Assuntos
Metionina/análogos & derivados , Penicillium/química , Pteridinas/química , Pteridinas/isolamento & purificação , Metionina/química , Metionina/isolamento & purificação , Metionina/metabolismo , Conformação Molecular , Oligopeptídeos , Penicillium/classificação , Penicillium/metabolismo , Pteridinas/metabolismo , Especificidade da Espécie , EstereoisomerismoRESUMO
3-Alkyl pyridinium alkaloids (3-APAs) are common secondary metabolites in marine sponges of the order Haplosclerida. In recent years, our laboratory has isolated and synthesized several new members of this family such as haliclamines C-F, viscosamine, viscosaline and a cyclic monomer. All of them were isolated from the Arctic sponge Haliclona viscosa collected in Spitsbergen, Norway. In this article we report the syntheses of these secondary metabolites from Haliclona viscosa and related compounds and give a short overview of the bioactivity.
Assuntos
Haliclona/química , Compostos de Piridínio/síntese química , Animais , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Produtos Biológicos , Compostos de Piridínio/química , Compostos de Piridínio/farmacologiaRESUMO
Spectroscopic investigations reveal that a hydroquinone pyridinium alkaloid isolated from the leaves of pomegranates Punica granatum L. (X-ray) exists as a mixture of a conjugated and a cross-conjugated heterocyclic mesomeric betaine in aqueous and DMSO-d6 solution. Twofold deprotonation yields an anionic tripole.
Assuntos
Alcaloides/química , Lythraceae/química , Modelos Moleculares , Estrutura MolecularRESUMO
Nucleophilic substitution of 4-(dimethylamino)pyridine on pentachloropyridine yielded pentakis(pyridine-2,3,4,5,6-pentayl)pyridinium, tris-(3,5-dichloropyridine-2,4,6-triyl)pyridinium, or (tetrachloropyridin-4-yl)pyridinium depending on the reaction conditions. Nucleophilic substitution with water, hydroxides, and alcoholates resulted in new betaines and highly substituted pyridines. [structure: see text]
Assuntos
Oxigênio/química , Piridinas/síntese química , Cátions , Indicadores e Reagentes , Espectroscopia de Ressonância Magnética , PolímerosRESUMO
Nucleophilic substitutions on pentachloropyridine with 4-(dimethylamino)pyridine, 4-aminopyridine, and 4-(pyrrolidin-1-yl)pyridine give mono-, tri- and pentacationic pyridine-hetarenium salts. The mono-, tri- and pentacationic 4-aminopyridine derivatives can be deprotonated to neutral compounds in solution, or protonated to di-, hexa- and decacationic pyridine derivatives, respectively. Successive substitutions with different heteroaromatic nucleophiles give pyridines with two distinct types of heteroarenium substituents.