RESUMO
Algae have multiple similarities with fungi, with both belonging to the Thallophyte, a polyphyletic group of non-mobile organisms grouped together on the basis of similar characteristics, but not sharing a common ancestor. The main difference between algae and fungi is noted in their metabolism. In fact, although algae have chlorophyll-bearing thalloids and are autotrophic organisms, fungi lack chlorophyll and are heterotrophic, not able to synthesize their own nutrients. However, our studies have shown that the extremophilic microalga Galderia sulphuraria (GS) can also grow very well in heterotrophic conditions like fungi. This study was carried out using several approaches such as scanning electron microscope (SEM), gas chromatography/mass spectrometry (GC/MS), and infrared spectrophotometry (ATR-FTIR). Results showed that the GS, strain ACUF 064, cultured in autotrophic (AGS) and heterotrophic (HGS) conditions, produced different biomolecules. In particular, when grown in HGS, the algae (i) was 30% larger, with an increase in carbon mass that was 20% greater than AGS; (ii) produced higher quantities of stearic acid, oleic acid, monounsaturated fatty acids (MUFAs), and ergosterol; (iii) produced lower quantities of fatty acid methyl esters (FAMEs) such as methyl palmytate, and methyl linoleate, saturated fatty acids (SFAs), and poyliunsaturated fatty acids (PUFAs). ATR-FTIR and principal component analysis (PCA) statistical analysis confirmed that the macromolecular content of HGS was significantly different from AGS. The ability to produce different macromolecules by changing the trophic conditions may represent an interesting strategy to induce microalgae to produce different biomolecules that can find applications in several fields such as food, feed, nutraceutical, or energy production.
Assuntos
Ácidos Graxos/metabolismo , Rodófitas/crescimento & desenvolvimento , Humanos , Espectrometria de Massas , Rodófitas/metabolismoRESUMO
Silybin A and B were separated from commercial silibinin using the preparative HPLC method. The described method is rapid and effective in obtaining gram-scale amounts of two diastereoisomers with minimal effort. In our approach, silibinin was dissolved in THF (solubility greater than 100 mg/mL), an alternative solvent to H2O or MeOH in which silibinin has a very low solubility (ca 0.05-1.5 mg/mL), and then separated into its two components using preparative RP-HPLC. By starting with purified diastereoisomers, it was possible to obtain the two enantiomers of 2,3-dehydrosilybin in good yields and optically pure using an efficient oxidation procedure. All of the purified products were fully characterised using NMR (¹H, ¹³C), CD, [α](D), and ESI MS analyses. The purities of the products, which were evaluated using analytical HPLC, were greater than 98% in all cases.
Assuntos
Antioxidantes/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Silybum marianum/química , Silimarina/isolamento & purificação , Antioxidantes/química , Oxirredução , Silibina , Silimarina/química , EstereoisomerismoRESUMO
The use of Boc as a nucleobase-protecting group in the synthesis of sugar-modified thymidine analogs is reported. Boc was easily inserted at N(3) by a simple and high-yielding reaction and found to be stable to standard treatments for the removal of Ac and (t) BuMe(2) Si (TBDMS) groups, as well as to ZnBr(2) -mediated 4,4'-dimethoxytrityl (DMTr) deprotection. Boc Protection proved to be completely resistant to the strong basic conditions required to regioselectively achieve O-alkylation, therefore, providing synthetic access to a variety of sugar-alkylated nucleoside analogs. To demonstrate the feasibility of this approach, two 3'-O-alkylated thymidine analogs have been synthesized in high overall yields and fully characterized.
Assuntos
Carboidratos/química , Ésteres do Ácido Fórmico/química , Nucleosídeos/química , Timidina/química , Alquilação , Modelos Químicos , Nucleosídeos/síntese química , EstereoisomerismoRESUMO
A small library of sugar-modified guanosine derivatives has been prepared, starting from a common intermediate, fully protected on the nucleobase. Insertion of myristoyl chains and of diverse hydrophilic groups, such as an oligoethylene glycol, an amino acid or a disaccharide chain, connected through in vivo reversible ester linkages, or of a charged functional group provided different examples of amphiphilic guanosine analogues, named G1-G7 herein. All of the sugar-modified derivatives were positive in the potassium picrate test, showing an ability to form G-tetrads. CD spectra demonstrated that, as dilute solutions in CHCl(3), distinctive G-quadruplex systems may be formed, with spatial organisations dependent upon the structural modifications. Two compounds, G1 and G2, proved to be good low-molecular-weight organogelators in polar organic solvents, such as methanol, ethanol and acetonitrile. Ion transportation experiments through phospholipid bilayers were carried out to evaluate their ability to mediate H(+) transportation, with G5 showing the highest activity within the investigated series. Moreover, G3 and G5 exhibited a significant cytotoxic profile against human MCF-7 cancer cells in in vitro bioassays.
Assuntos
Antineoplásicos/química , Antineoplásicos/síntese química , Guanosina/síntese química , Antineoplásicos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Quadruplex G , Guanosina/análogos & derivados , Guanosina/farmacologia , Humanos , Interações Hidrofóbicas e Hidrofílicas , Estrutura MolecularRESUMO
Silybin is the major flavonolignan of silymarin and it displays a plethora of biological effects, generally ascribed to its antioxidant properties. Herein we shall describe an efficient synthetic strategy to obtain a variety of new and more water-soluble silybin and 2,3-dehydrosilybin (DHS) derivatives in which the 23-hydroxyl group was converted to a sulfate, phosphodiester, or amine group, using a solution-phase approach. Furthermore a new and efficient method for the preparation of DHS from silybin was developed and optimised. The antioxidant properties of the new compounds were evaluated in a cellular model in vivo and they displayed an antioxidant activity comparable to or higher than silybin and DHS, being able to prevent H(2)O(2)-induced generation of intracellular reactive oxygen species (ROS). Most of the derivatives also displayed a better hydrophilicity while retaining the biological activities of silybin and they might broaden the in vivo applications of this class of natural compounds.
Assuntos
Antioxidantes/síntese química , Silimarina/química , Animais , Antioxidantes/química , Antioxidantes/farmacologia , Linhagem Celular , Ratos , Silibina , Silimarina/síntese química , Silimarina/farmacologia , EstereoisomerismoRESUMO
A novel fluorescently labelled synthetic ionophore, based on a cyclic phosphate-linked disaccharide (CyPLOS) backbone and decorated with four tetraethylene glycol tails carrying dansyl units, has been synthesised in 12 steps in 26% overall yield. The key intermediate in the synthetic strategy is a novel glucoside building block, serving through its 2- and 3-hydroxy groups as the anchor point for flexible tetraethylene glycol tentacles with reactive azido moieties at their ends. To test the versatility of this glucoside scaffold, it was preliminarily functionalised with a set of diverse probes--as fluorescent, redox-active or hydrophobic tags--either by reduction of the azides followed by condensation with activated carboxylic acid derivatives, or by a direct coupling with a terminal alkyne in a Cu(I)-promoted 1,3-dipolar cycloaddition. Tagging of the monomeric building block with dansyl residues allowed us to prepare a fluorescent, amphiphilic macrocycle, which was investigated for its propensity to self-aggregate in CDCl(3)--studied by means of concentration-dependent (31)P NMR spectroscopy experiments--and in aqueous solution, in which combined dynamic light scattering (DLS) and small-angle neutron scattering (SANS) measurements provided a detailed physico-chemical analysis of the self-assembled systems, mainly organised in the form of large vesicles. Its ion-transport properties through phospholipid bilayers, determined by HPTS fluorescence assays, showed this compound to be more active than the previously synthesised CyPLOS congeners. Solvent-dependent fluorescence changes for the labelled ionophore in liposome suspension established that the dansyl moieties are dispersed in environments with polarity intermediate between those of CH(2)Cl(2) and propan-2-ol, suggesting that the CyPLOS tentacles infiltrate the mid-polar region of the membranes.
Assuntos
Corantes Fluorescentes/química , Ionóforos/química , Compostos Macrocíclicos/química , Compostos Macrocíclicos/síntese química , Oligossacarídeos/química , Oligossacarídeos/síntese química , Água/química , Transporte de Íons , Ionóforos/metabolismo , Espectroscopia de Ressonância Magnética , Estrutura MolecularRESUMO
[structure: see text] A new and versatile on-line automated solid-phase approach to obtain cyclic PNA (I and III) and cyclic PNA-DNA chimeras (II) in highly pure form has been developed. Starting from a Tentagel matrix functionalized with a 3-chloro-4-hydroxyphenylacetic linker, the synthesis of representative, new cyclic molecules by standard peptide and phosphoramidite-based chemistry has been achieved.
Assuntos
DNA/síntese química , Ácidos Nucleicos Peptídicos/síntese química , Ciclização , DNA/química , Estrutura Molecular , Ácidos Nucleicos Peptídicos/químicaRESUMO
The ability of the water-soluble protein extracts from Zea mais L. cv. PR32-B10 to degrade some representative polycyclic aromatic hydrocarbons (PAHs), has been evaluated. Surface sterilized seeds of corn (Zea mais L. Pioneer cv. PR32-B10) were hydroponically cultivated in a growth chamber under no-stressful conditions. The water-soluble protein extracts isolated from maize tissues showed peroxidase, polyphenol oxidase and catalase activities. Incubation of the extracts with naphthalene, fluorene, phenanthrene and pyrene, led to formation of oxidized and/or degradation products. GC-MS and TLC monitoring of the processes showed that naphthalene, phenanthrene, fluorene and pyrene underwent 100%, 78%, 92% and 65% oxidative degradation, respectively, after 120 min. The chemical structure of the degradation products were determined by (1)H NMR and ESI-MS spectrometry.
Assuntos
Extratos Vegetais/química , Proteínas de Plantas/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes do Solo/análise , Zea mays/química , Biodegradação Ambiental , Cromatografia em Camada Fina , Fluorenos/análise , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Ressonância Magnética , Naftalenos/análise , Oxirredução , Fenantrenos/análise , Pirenos/análise , Solubilidade , Zea mays/enzimologia , Zea mays/metabolismoRESUMO
[reaction: see text] An easy and efficient solid-phase strategy to obtain 5'- and 3'-oligonucleotide conjugates in highly pure form has been developed. Ad hoc derivatized solid supports, to which the first nucleoside unit can be attached through a phosphate linkage, have been exploited both in a pre- and post-DNA assembly conjugation approach. A number of 5'- or 3'- oligonucleotide conjugates, incorporating a variety of labels covalently linked through a phosphodiester or a phosphoramidate bond, have been synthesized and characterized.
Assuntos
Oligonucleotídeos/síntese química , Estrutura Molecular , Oligonucleotídeos/química , Compostos Organofosforados/químicaRESUMO
An easy and efficient strategy to obtain libraries of 5'-phosphodiester and 5'-phosphoramidate monoester nucleoside analogues in a highly pure form has been developed, starting from a new nucleoside based solid support. The nucleoside scaffold has been anchored through a 5'-phosphodiester linkage to Tentagel HL resin, functionalized with a 3-chloro-4-hydroxyphenylacetic linker. The solid phase synthesis of small libraries of 5'-phosphodiester and 5'-phosphoramidate monoester thymidine analogues is also reported.
Assuntos
Amidas/síntese química , Ésteres/síntese química , Nucleosídeos/síntese química , Compostos Organofosforados/síntese química , Amidas/química , Ésteres/química , Estrutura Molecular , Nucleosídeos/química , Compostos Organofosforados/química , Ácidos Fosfóricos/químicaRESUMO
The excess electron transfer in a G-quadruplex is successfully probed by using the reaction of hydrated electrons with quadruplex complex of pentamers and the 8-bromoguanine moieties as the detection system.
Assuntos
DNA/química , DNA/metabolismo , Transporte de Elétrons , Quadruplex G , Guanina/análogos & derivados , Guanina/química , Oligodesoxirribonucleotídeos/química , Água/químicaRESUMO
An easy and efficient strategy to obtain new nucleoside based solid supports in which the nucleoside moieties have been anchored to the solid support through the nucleobase is here proposed. A simple and efficient solid-phase synthesis of 5' and 3'-derivatized uridine analogues has so been developed, following methodologies well established in organic chemistry.
Assuntos
Nucleosídeos/química , Uridina/análogos & derivados , Uridina/síntese química , Química Orgânica/métodos , Indicadores e ReagentesRESUMO
Novel compound 1, as the first example of cyclic ADP-ribose analogs containing a pyrimidine residue, was synthesized by a chemical strategy employing a Mitsunobu reaction for the condensation of the glucosyl moiety on protected uridine, and a Matsuda procedure for the cyclization step.
Assuntos
ADP-Ribose Cíclica/análogos & derivados , ADP-Ribose Cíclica/síntese química , Nucleotídeos Cíclicos/síntese química , Uridina Difosfato Glucose/análogos & derivados , Uridina Difosfato Glucose/síntese química , Indicadores e Reagentes , Modelos MolecularesRESUMO
The photophysical and photochemical properties of 5-benzyluracil and 5,6-benzyluracil, the latter produced by photocyclization of the former through irradiation with femtosecond UV laser pulses, are investigated both experimentally and theoretically. The absorption spectra of the two molecules are compared, and the principal electronic transitions involved are discussed, with particular emphasis on the perturbation induced on the two chromophore species (uracil and benzene) by their proximity. The photoproduct formation for different irradiation times was verified with high-performance liquid chromatography and nuclear magnetic resonance measurements. The steady-state fluorescence demonstrates that the fluorescence is a distinctive physical observable for detection and selective identification of 5- and 5,6-benzyluracil. The principal electronic decay paths of the two molecules, obtained through TDDFT calculations, explain the features observed in the emission spectra and the photoreactivity of 5-benzyluracil. The order of magnitude of the lifetime of the excited states is derived with steady-state fluorescence anisotropy measurements and rationalized with the help of the computational findings. Finally, the spectroscopic data collected are used to derive the photocyclization and fluorescence quantum yields. In obtaining a global picture of the photophysical and photochemical properties of the two molecules, our findings demonstrates that the use of 5-benzyluracil as a model system to study the proximity relations of a DNA base with a close-lying aromatic amino acid is valid at a local level since the main characteristics of the decay processes from the excited states of the uracil/thymine molecules remain almost unchanged in 5-benzyluracil, the main perturbation arising from the presence of the close-lying aromatic group.
Assuntos
DNA/química , Elétrons , Uracila/análogos & derivados , Ciclização , Modelos Químicos , Processos Fotoquímicos , Teoria Quântica , Espectrometria de Fluorescência , Raios Ultravioleta , Uracila/químicaRESUMO
A first solid phase approach to obtain monosubstituted CD conjugates to different labels has been developed. A new solid support has been designed to get a variety of C-6 monofunctionalized CDs (α, ß, MeßCD and HPßCD) covalently linked through a phosphodiester bridge to different labels, in highly pure form and under very mild detachment conditions.
Assuntos
Ciclodextrinas/química , Ciclodextrinas/síntese química , Espectroscopia de Ressonância Magnética , Compostos Organofosforados/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
A series of d((5')TGGGAG(3')) sequences, 5'-conjugated with a variety of aromatic groups through phosphodiester linkages, were synthesized, showing CD spectra diagnostic of parallel-stranded, tetramolecular G-quadruplex structures. When tested for anti-HIV-1 and HIV-2 activity, potent inhibition of HIV-1 infection in CEM cell cultures was found, associated with high selectivity index values. Surface Plasmon Resonance assays revealed specific binding to HIV-1 gp120 and gp41.
Assuntos
Fármacos Anti-HIV/química , Quadruplex G , Oligonucleotídeos/química , Fármacos Anti-HIV/síntese química , Fármacos Anti-HIV/farmacologia , Linhagem Celular , Avaliação Pré-Clínica de Medicamentos , HIV/metabolismo , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/metabolismo , Proteína gp41 do Envelope de HIV/química , Proteína gp41 do Envelope de HIV/metabolismo , Humanos , Oligonucleotídeos/síntese química , Oligonucleotídeos/farmacologia , Ressonância de Plasmônio de SuperfícieRESUMO
Ionophores are an important class of synthetic molecules which mimic natural ion channels or carriers. Here we report the aggregation behavior in pseudo-physiological environment of three Cyclic Phosphate-Linked Oligosaccharides (CyPLOS) derivatives, synthetic ion transporters based on cyclic, phosphate-linked disaccharide skeleton differing for the nature of the tails (tetraethylene-TEG glycol and/or n-undecyl chains) attached to the C-2 and C-3 of the constitutive monosaccharides. Their aggregation behavior has been studied by a combined use of dynamic light scattering (DLS), electron paramagnetic resonance spectroscopy (EPR) and Small Angle Neutron Scattering (SANS). DLS measurements were performed to reveal the formation and size distribution of the CyPLOS aggregates. EPR measurements, by using 5-doxyl stearic acid (5-DSA) as spin-probe, showed that the aggregates are mainly due to the formation of double layers and allowed to analyze the local fluidity. Finally, SANS measurements allowed estimating the layer thickness of the double layers. Our results indicate that the three CyPLOS analogs show self-aggregation properties that depend on the different nature of the inserted tails.
Assuntos
Ionóforos/química , Nanoestruturas/química , Oligossacarídeos/química , Fosfatos/química , Ciclização , Espectroscopia de Ressonância de Spin Eletrônica , Luz , Nanoestruturas/ultraestrutura , Espalhamento de RadiaçãoRESUMO
Novel thymidine- or uridine-based nucleolipids, containing one hydrophilic oligo(ethylene glycol) chain and one or two oleic acid residues (called ToThy, HoThy and DoHu), have been synthesized with the aim to develop bio-compatible nanocarriers for drug delivery and/or produce pro-drugs. Microstructural characterization of their aggregates has been determined in pure water and in pseudo-physiological conditions through DLS and SANS experiments. In all cases stable vesicles, with mean hydrodynamic radii ranging between 120 nm and 250 nm have been revealed. Biological validation of the nucleolipidic nanocarriers was ensured by evaluation of their toxicological profiles, performed by administration of the nanoaggregates to a panel of different cell lines. ToThy exhibited a weak cytotoxicity and, at high concentration, some ability to interfere with cell viability and/or proliferation. In contrast, DoHu and HoThy exhibited no toxicological relevance, behaving similarly to POPC-based liposomes, widely used for systemic drug delivery. Taken together, these results show nucleolipid-based nanocarriers as finely tunable, multi-functional self-assembling materials of interest for the in vivo transport of biomolecules or drugs.
Assuntos
Portadores de Fármacos/síntese química , Nanocápsulas/química , Ácidos Oleicos/síntese química , Timidina/análogos & derivados , Uridina/análogos & derivados , Células 3T3-L1 , Animais , Células CACO-2 , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Portadores de Fármacos/química , Portadores de Fármacos/toxicidade , Sistemas de Liberação de Medicamentos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Ácidos Oleicos/química , Ácidos Oleicos/toxicidade , Pró-Fármacos/síntese química , Pró-Fármacos/química , Ratos , Timidina/síntese química , Timidina/química , Timidina/toxicidade , Uridina/síntese química , Uridina/química , Uridina/toxicidadeRESUMO
A versatile approach to develop libraries of diverse 5',3'-bis-conjugated oligonucleotides (ODNs) is here described. The usage of ad hoc derivatized solid supports, to which the first nucleoside unit is attached through a phosphate linkage, opens easy synthetic access to a large variety of hybrid bis-conjugated oligomers. The G-quadruplex forming d((5')TGGGAG(3')) sequence, as a potential anti-HIV agent, has been here used as a model system.
Assuntos
Fármacos Anti-HIV/síntese química , Quadruplex G , Oligodesoxirribonucleotídeos/síntese química , Fármacos Anti-HIV/química , Oligodesoxirribonucleotídeos/química , Bibliotecas de Moléculas PequenasRESUMO
We here describe the synthesis of a series of novel bicyclic ribonucleoside derivatives, with 18-crown-6 ether moieties attached via their ribose 2- and 3- positions, as first examples of crown ether ring-fused nucleosides, to be evaluated as antiviral and/or antitumoral agents.