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1.
J Phys Chem A ; 128(6): 1109-1123, 2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-38316031

RESUMEN

We report a combined experimental and computational study of adenosine cation radicals that were protonated at adenine and furnished with a radical handle in the form of an acetoxyl radical, •CH2COO, that was attached to ribose 5'-O. Radicals were generated by collision-induced dissociation (CID) and characterized by tandem mass spectrometry and UV-vis photodissociation action spectroscopy. The acetoxyl radical was used to probe the kinetics of intramolecular hydrogen transfer from the ribose ring positions that were specifically labeled with deuterium at C1', C2', C3', C4', C5', and in the exchangeable hydroxyl groups. Hydrogen transfer was found to chiefly involve 3'-H with minor contributions by 5'-H and 2'-H, while 4'-H was nonreactive. The hydrogen transfer rates were affected by deuterium isotope effects. Hydrogen transfer triggered ribose ring cleavage by consecutive dissociations of the C4'-O and C1'-C2' bonds, resulting in expulsion of a C6H9O4 radical and forming a 9-formyladenine ion. Rice-Ramsperger-Kassel-Marcus (RRKM) and transition-state theory (TST) calculations of unimolecular constants were carried out using the effective CCSD(T)/6-311++G(3d,2p) and M06-2X/aug-cc-pVTZ potential energy surfaces for major isomerizations and dissociations. The kinetic analysis showed that hydrogen transfer to the acetoxyl radical was the rate-determining step, whereas the following ring-opening reactions in ribose radicals were fast. Using DFT-computed energies, a comparison was made between the thermochemistry of radical reactions in adenosine and 2'-deoxyadenosine cation radicals. The 2'-deoxyribose ring showed lower TS energies for both the rate-determining 3'-H transfer and ring cleavage reactions.


Asunto(s)
Adenosina , Desoxiadenosinas , Ribosa , Cinética , Deuterio , Desoxirribosa/química , Hidrógeno , Cationes/química , Radicales Libres/química
2.
Biochem Biophys Res Commun ; 532(4): 662-667, 2020 11 19.
Artículo en Inglés | MEDLINE | ID: mdl-32907714

RESUMEN

DNA triplex is a popular, higher-order structural arrangement with several biological importance. In the present article, we examined the impact of replacing regular deoxyribose sugar by conformationally locked sugar on the structure/stability of a DNA triplex. We individually modified single strands of DNA triplex (3'-5' strand/5'-3' strand) and observed the consequences in terms of the overall structural integrity and energetics using all-atom explicit-solvent Gaussian accelerated molecular dynamics simulations at biological salt concentration. As anticipated, the control DNA triplex maintained the structural integrity throughout the simulations. However, it is striking to note that a duplex evolved from both the modified systems (3'-5' modified triplex as well as 5'-3' modified triplex). The resultant duplexes in both cases contain a modified strand and a regular strand, whereas the third strand (regular ssDNA) left the binding site entirely. We observed that the modified ssDNA binds to the regular ssDNA with high affinities in both the hybrid duplexes (∼-64 kcal/mol), significantly higher than the regular ssDNA - regular ssDNA interaction (∼-52 kcal/mol). The remarkable binding of modified ssDNA to regular ssDNA can be utilized to design new antisense oligonucleotides, and the role of such modified oligonucleotides in anticancer therapy is foreseen.


Asunto(s)
ADN/química , Desoxirribosa/química , Simulación de Dinámica Molecular , Conformación de Ácido Nucleico
3.
Microvasc Res ; 131: 104035, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32593538

RESUMEN

BACKGROUND: Delayed neovascularisation of tissue-engineered (TE) complex constructs is a major challenge that causes their failure post-implantation. Although significant progress has been made in the field of angiogenesis, ensuring rapid neovascularisation still remains a challenge. The use of pro-angiogenic agents is an effective approach to promote angiogenesis, and vascular endothelial growth factor (VEGF) has been widely studied both at the biological and molecular levels and is recognised as a key stimulator of angiogenesis. However, the exogenous use of VEGF in an uncontrolled manner has been shown to result in leaky, permeable and haemorrhagic vessels. Thus, researchers have been actively seeking alternative agents to upregulate VEGF production rather than exogenous use of VEGF in TE systems. We have previously revealed the potential of 2-deoxy-d-ribose (2dDR) as an alternative pro-angiogenic agent to induce angiogenesis and accelerates wound healing. However, to date, there is not any clear evidence on whether 2dDR influences the angiogenic cascade that involves VEGF. METHODS: In this study, we explored the angiogenic properties of 2dDR either by its direct application to human aortic endothelial cells (HAECs) or when released from commercially available alginate dressings and demonstrated that when 2dDR promotes angiogenesis, it also increases the VEGF production of HAECs. RESULTS: The VEGF quantification results suggested that VEGF production by HAECs was increased with 2dDR treatment but not with other sugars, including 2-deoxy-l-ribose (2dLR) and d-glucose (DG). The stability studies demonstrated that approximately 40-50% of the 2dDR had disappeared in the media over 14 days, either in the presence or absence of HAECs, and the reduction was higher when cells were present. The concentration of VEGF in the media also fell after day 4 associated with the reduction in 2dDR. CONCLUSION: This study suggests that 2dDR (but not other sugars tested in this study) stimulates angiogenesis by increasing the production of VEGF. We conclude 2dDR appears to be a practical and effective indirect route to upregulating VEGF for several days, leading to increased angiogenesis.


Asunto(s)
Inductores de la Angiogénesis/farmacología , Membrana Corioalantoides/irrigación sanguínea , Desoxirribosa/farmacología , Células Endoteliales/efectos de los fármacos , Neovascularización Fisiológica/efectos de los fármacos , Factor A de Crecimiento Endotelial Vascular/metabolismo , Alginatos/química , Inductores de la Angiogénesis/química , Animales , Células Cultivadas , Embrión de Pollo , Preparaciones de Acción Retardada , Desoxirribosa/química , Portadores de Fármacos , Estabilidad de Medicamentos , Células Endoteliales/metabolismo , Humanos , Transducción de Señal , Regulación hacia Arriba
4.
J Tissue Eng Regen Med ; 14(7): 973-988, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32473079

RESUMEN

The absorption capacity of cotton dressings is a critical factor in their widespread use where they help absorb wound exudate. Cotton wax dressings, in contrast, are used for wounds where care is taken to avoid adhesion of dressings to sensitive wounds such as burn injuries. Accordingly, we explored the loading of 2-deoxy-D-ribose (2dDR), a small sugar, which stimulates angiogenesis and wound healing in normal and diabetic rats, into both types of dressings and measured the release of it over several days. The results showed that approximately 90% of 2dDR was released between 3 and 5 days when loaded into cotton dressings. For wax-coated cotton dressings, several methods of loading of 2dDR were explored. A strategy similar to the commercial wax coating methodology was found the best protocol which provided a sustained release over 5 days. Cytotoxicity analysis of 2dDR loaded cotton dressing showed that the dressing stimulated metabolic activity of fibroblasts over 7 days confirming the non-toxic nature of this sugar-loaded dressings. The results of the chick chorioallantoic membrane (CAM) assay demonstrated a strong angiogenic response to both 2dDR loaded cotton dressing and to 2dDR loaded cotton wax dressings. Both dressings were found to increase the number of newly formed blood vessels significantly when observed macroscopically and histologically. We conclude this study offers a simple approach to developing affordable wound dressings as both have the potential to be evaluated as pro-active dressings to stimulate wound healing in wounds where management of exudate or prevention of adherence to the wounds are clinical requirements.


Asunto(s)
Inductores de la Angiogénesis , Vendajes , Fibra de Algodón , Desoxirribosa , Ensayo de Materiales , Neovascularización Fisiológica/efectos de los fármacos , Inductores de la Angiogénesis/química , Inductores de la Angiogénesis/farmacología , Animales , Embrión de Pollo , Membrana Corioalantoides/metabolismo , Desoxirribosa/química , Desoxirribosa/farmacología , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/terapia , Ratones , Células 3T3 NIH , Ratas , Cicatrización de Heridas
5.
Methods Mol Biol ; 1881: 129-151, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30350203

RESUMEN

Cell proliferation plays a central role in the pathogenesis of every neoplastic disease as well as many other types of illness. Labeling of newly replicated DNA with deuterium (2H), a nonradioactive isotope of hydrogen, administered to the patients in drinking water (2H2O) is a safe and reliable method to measure the in vivo birth rates of cells. Here, we describe a protocol to measure chronic lymphocytic leukemia B-cell birth/proliferation and death rates over time using this approach.


Asunto(s)
Linfocitos B/patología , Desoxirribosa/análisis , Óxido de Deuterio/administración & dosificación , Cromatografía de Gases y Espectrometría de Masas/métodos , Leucemia Linfocítica Crónica de Células B/patología , Apoptosis , Linfocitos B/metabolismo , Proliferación Celular , ADN/química , ADN/aislamiento & purificación , Replicación del ADN , Desoxirribosa/química , Óxido de Deuterio/química , Cromatografía de Gases y Espectrometría de Masas/instrumentación , Humanos , Cinética , Leucemia Linfocítica Crónica de Células B/sangre
6.
Nat Commun ; 9(1): 3105, 2018 08 06.
Artículo en Inglés | MEDLINE | ID: mdl-30082730

RESUMEN

5-Deoxyribose is formed from 5'-deoxyadenosine, a toxic byproduct of radical S-adenosylmethionine (SAM) enzymes. The degradative fate of 5-deoxyribose is unknown. Here, we define a salvage pathway for 5-deoxyribose in bacteria, consisting of phosphorylation, isomerization, and aldol cleavage steps. Analysis of bacterial genomes uncovers widespread, unassigned three-gene clusters specifying a putative kinase, isomerase, and sugar phosphate aldolase. We show that the enzymes encoded by the Bacillus thuringiensis cluster, acting together in vitro, convert 5-deoxyribose successively to 5-deoxyribose 1-phosphate, 5-deoxyribulose 1-phosphate, and dihydroxyacetone phosphate plus acetaldehyde. Deleting the isomerase decreases the 5-deoxyribulose 1-phosphate pool size, and deleting either the isomerase or the aldolase increases susceptibility to 5-deoxyribose. The substrate preference of the aldolase is unique among family members, and the X-ray structure reveals an unusual manganese-dependent enzyme. This work defines a salvage pathway for 5-deoxyribose, a near-universal metabolite.


Asunto(s)
Bacillus thuringiensis/enzimología , Desoxirribosa/química , S-Adenosilmetionina/química , Aldehído-Liasas/química , Aldehídos/química , Transporte Biológico , Cristalografía por Rayos X , Desoxiadenosinas/química , Escherichia coli/metabolismo , Eliminación de Gen , Isomerasas/química , Metabolómica , Fenotipo , Fosfotransferasas/química , Conformación Proteica , Ribosamonofosfatos/química
7.
ChemMedChem ; 13(1): 97-104, 2018 01 08.
Artículo en Inglés | MEDLINE | ID: mdl-29160955

RESUMEN

The synthesis of hitherto unknown pyrrolo[2,1-f][1,2,4]triazine C-nucleosides is described. Structural variations (chlorine, bromine, iodine, and cyano groups) were introduced at position 7 of 4-aza-7,9-dideazaadenine. In addition, pyrrolo[2,1-f][1,2,4]triazine C-nucleosides bearing a 2'-deoxy-, 2',3'-dideoxy-, and 2',3'-dehydrodideoxyribose moiety were also prepared. Among these analogues, the pyrrolo[2,1-f][1,2,4]triazine C-ribonucleosides with either a hydrogen atom or cyano group at position 7 of the nucleobase displayed potent cytotoxic activity in a panel of various cancer cell lines.


Asunto(s)
Antineoplásicos/síntesis química , Antivirales/síntesis química , Desoxirribosa/química , Nucleósidos/química , Ribosa/química , Triazinas/química , Antineoplásicos/farmacología , Antivirales/farmacología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , VIH-1/efectos de los fármacos , Humanos , Pirroles/química , Relación Estructura-Actividad
8.
Sci Rep ; 7: 40293, 2017 01 13.
Artículo en Inglés | MEDLINE | ID: mdl-28084308

RESUMEN

DNA/RNA hybrid duplexes are prevalent in many cellular functions and are an attractive target form for electrochemical biosensing and electric nanodevice. However the electronic conductivities of DNA/RNA hybrid duplex remain relatively unexplored and limited further technological applications. Here cyclopropyl-modified deoxyribose- and ribose-adenosines were developed to explore hole transport (HT) in both DNA duplex and DNA/RNA hybrids by probing the transient hole occupancies on adenine tracts. HT yields through both B-form and A-form double helixes displayed similar shallow distance dependence, although the HT yields of DNA/RNA hybrid duplexes were lower than those of DNA duplexes. The lack of oscillatory periods and direction dependence in HT through both helixes implied efficient hole propagation can be achieved via the hole delocalization and coherent HT over adenine tracts, regardless of the structural variations.


Asunto(s)
ADN de Forma A/química , ADN/química , ARN/química , ADN/genética , ADN de Forma A/genética , Desoxirribosa/química , Conformación de Ácido Nucleico , Hibridación de Ácido Nucleico/genética , ARN/genética , Ribosa/química , Termodinámica
9.
Acta Biochim Pol ; 64(1): 195-198, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-27991936

RESUMEN

Deoxyribose test has been widely used for determination of reactivities of various compounds for the hydroxyl radical. The test is based on the formation of hydroxyl radical by Fe2+ complex in the Fenton reaction. We propose a modification of the deoxyribose test to detect strong iron binding, inhibiting participation of Fe2+ in the Fenton reaction, on the basis of examination of concentration dependence of deoxyribose degradation on Fe2+ concentration, at a constant concentration of a chelating agent.


Asunto(s)
Desoxirribosa/química , Peróxido de Hidrógeno/química , Radical Hidroxilo/química , Hierro/química , Sitios de Unión , Quelantes/química , Técnicas de Laboratorio Clínico/métodos , Relación Dosis-Respuesta a Droga , Quelantes del Hierro/química
10.
Chem Pharm Bull (Tokyo) ; 64(9): 1315-20, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27581636

RESUMEN

Cross-linking is a widely-used technology in the studies of DNA, RNA and their complexes with proteins. Intrinsically active alkylating moieties and photo-activated agents are chemically or enzymatically incorporated into nucleic acids. Thionucleobases resemble the corresponding natural bases, and form cross-links by UVA irradiation. They form cross-links only with a site in close contact, thereby allowing identification of the contacts within the nucleic acids and/or between the nucleic acids and proteins in complex nucleoprotein assemblies. On the other hand, the thionucleobase forms a cross-link less efficiently for the reaction with the opposite natural base in the DNA duplex. In this study, 6-thioguanine was connected to 2'-deoxyribose through an ethylene linker at the 1'-position (Et-thioG). The linker was expected to bring the 6-thio group close to the nucleobase in the opposite strand. In a duplex in which the 2'-deoxy-6-thioguanosine (6-thio-dG) did not form a crosslink, Et-thioG efficiently formed crosslink with a high selectivity for T by UVA irradiation, but with a much lower efficiency for dA, dG, dC, 5-methyl-dC or dU. Interestingly, the yield of the photo-crosslinked product with dT was effectively improved in the presence of dithiothreitol or sodium hydrosulfide (NaSH) at a low UVA irradiation dose. The efficient and selective cross-link formation at a low UVA dose may be beneficial for the biological application of Et-thioG.


Asunto(s)
Reactivos de Enlaces Cruzados/química , ADN/química , Desoxirribosa/química , Etilenos/química , Tioguanina/química , Timidina/química , Reactivos de Enlaces Cruzados/síntesis química , Procesos Fotoquímicos , Rayos Ultravioleta
11.
Org Biomol Chem ; 14(30): 7361-7, 2016 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-27417455

RESUMEN

A 3'-N,5'-S-bridging thiophosphoramidate analogue of thymidylyl-3',5'-thymidine was synthesised under aqueous conditions. (1)H NMR conformational measurements show that the 3'-N-substituted deoxyribose ring is biased towards the 'north', RNA-like conformation. Rate constants for hydrolysis of the analogue were measured at 90 °C in the pH range 1.3-10.9. The pH-log kobs profile displays a pH-independent region between approximately pH 7 and 10 (t1/2 ∼13 days). Under acidic conditions, kobs displays a first order dependence on [H3O(+)].


Asunto(s)
Fosfatos de Dinucleósidos/química , Compuestos Organofosforados/química , Cromatografía Líquida de Alta Presión/métodos , Desoxirribosa/análogos & derivados , Desoxirribosa/química , Fosfatos de Dinucleósidos/síntesis química , Concentración de Iones de Hidrógeno , Hidrólisis , Cinética , Espectroscopía de Resonancia Magnética , Conformación Molecular , Compuestos Organofosforados/síntesis química
12.
Basic Clin Pharmacol Toxicol ; 119(4): 412-7, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27061346

RESUMEN

The use of self-medication, which includes dietary supplements and over-the-counter drugs, is still on the rise, while safety issues are not well addressed yet. This especially holds for combinations. For example, iron supplements and magnesium peroxide both produce adverse effects via the formation of reactive oxygen species (ROS). This prompted us to investigate the effect of the combination of three different iron supplements with magnesium peroxide on ROS formation. Hydroxyl radical formation by the three iron supplements either combined with magnesium peroxide or alone was determined by performing a deoxyribose assay. Free iron content of iron supplements was determined using ferrozine assay. To determine hydrogen peroxide formation by magnesium peroxide, a ferrous thiocyanate assay was performed. Finally, electron spin resonance spectroscopy (ESR) was performed to confirm the formation of hydroxyl radicals. Our results show that magnesium peroxide induces the formation of hydrogen peroxide. All three iron supplements induced the formation of the extremely reactive hydroxyl radical, although the amount of radicals formed by the different supplements differed. It was shown that combining iron supplements with magnesium peroxide increases radical formation. The formation of hydroxyl radicals after the combination was confirmed with ESR. All three iron supplements contained labile iron and induced the formation of hydroxyl radicals. Additionally, magnesium peroxide in water yields hydrogen peroxide, which is converted into hydroxyl radicals by iron. Hence, iron supplements and magnesium peroxide is a hazardous combination and exemplifies that more attention should be given to combinations of products used in self-medication.


Asunto(s)
Antiácidos/efectos adversos , Suplementos Dietéticos/efectos adversos , Interacciones Alimento-Droga , Hierro de la Dieta/efectos adversos , Compuestos de Magnesio/efectos adversos , Peróxidos/efectos adversos , Especies Reactivas de Oxígeno/química , Autocuidado/efectos adversos , Antiácidos/química , Desoxirribosa/química , Espectroscopía de Resonancia por Spin del Electrón , Compuestos Ferrosos/efectos adversos , Compuestos Ferrosos/química , Humanos , Peróxido de Hidrógeno/agonistas , Peróxido de Hidrógeno/análisis , Peróxido de Hidrógeno/química , Concentración de Iones de Hidrógeno , Radical Hidroxilo/agonistas , Radical Hidroxilo/análisis , Radical Hidroxilo/química , Lactatos/efectos adversos , Lactatos/química , Compuestos de Magnesio/química , Países Bajos , Medicamentos sin Prescripción/efectos adversos , Concentración Osmolar , Peróxidos/química , Especies Reactivas de Oxígeno/análisis , Automedicación/efectos adversos
13.
Molecules ; 22(1)2016 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-28042856

RESUMEN

In the presence of transition metal ions and peroxides, polyphenols, well-known dietary antioxidants, can act as pro-oxidants. We investigated the effect of 13 polyphenols and their metabolites on oxidative degradation of deoxyribose by an •OH generating Fenton system (Fe2+-ethylenediaminetetraacetic acid (EDTA)-H2O2). The relationship between phenolics pro-oxidant/anti-oxidant effects and their molecular structure was analyzed using multivariate analysis with multiple linear regression and a backward stepwise technique. Four phenolics revealed a significant inhibitory effect on OH-induced deoxyribose degradation, ranging from 54.4% ± 28.6% (3,4-dihydroxycinnamic acid) to 38.5% ± 10.4% (catechin) (n = 6), correlating with the number of -OH substitutions (r = 0.58). Seven phenolics augmented the oxidative degradation of deoxyribose with the highest enhancement at 95.0% ± 21.3% (quercetin) and 60.6% ± 12.2% (phloridzin). The pro-oxidant effect correlated (p < 0.05) with the number of -OH groups (r = 0.59), and aliphatic substitutes (r = -0.22) and weakly correlated with the occurrence of a catechol structure within the compound molecule (r = 0.17). Selective dietary supplementation with phenolics exhibiting pro-oxidant activity may increase the possibility of systemic oxidative stress in patients treated with medications containing chelating properties or those with high plasma concentrations of H2O2 and non-transferrin bound iron.


Asunto(s)
Antioxidantes/química , Desoxirribosa/metabolismo , Ácido Edético/química , Oxidantes/química , Fenoles/química , Extractos Vegetales/química , Desoxirribosa/química , Frutas/química , Humanos , Peróxido de Hidrógeno/química , Oxidación-Reducción , Estrés Oxidativo , Verduras/química
14.
PLoS One ; 10(6): e0129963, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26098639

RESUMEN

Caffeic acid (CA) is a phenolic compound widely found in coffee beans with known beneficial effects in vivo. Many studies showed that CA has anti-inflammatory, anti-mutagenic, antibacterial and anti-carcinogenic properties, which could be linked to its antioxidant activity. Taking in consideration the reported in vitro antioxidant mechanism of other polyphenols, our working hypothesis was that the CA antioxidant activity could be related to its metal-chelating property. With that in mind, we sought to investigate the chemical antioxidant mechanism of CA against in vitro iron-induced oxidative damage under different assay conditions. CA was able to prevent hydroxyl radical formation promoted by the classical Fenton reaction, as determined by 2-deoxyribose (2-DR) oxidative degradation and DMPO hydroxylation. In addition to its ability to prevent hydroxyl radical formation, CA had a great inhibition of membrane lipid peroxidation. In the lipid peroxidation assays CA acted as both metal-chelator and as hydrogen donor, preventing the deleterious action promoted by lipid-derived peroxyl and alkoxyl radicals. Our results indicate that the observed antioxidant effects were mostly due to the formation of iron-CA complexes, which are able to prevent 2-DR oxidation and DMPO hydroxylation. Noteworthy, the formation of iron-CA complexes and prevention of oxidative damage was directly related to the pH of the medium, showing better antioxidant activity at higher pH values. Moreover, in the presence of lipid membranes the antioxidant potency of CA was much higher, indicating its enhanced effectiveness in a hydrophobic environment. Overall, our results show that CA acts as an antioxidant through an iron chelating mechanism, preventing the formation of free hydroxyl radicals and, therefore, inhibiting Fenton-induced oxidative damage. The chemical properties of CA described here--in association with its reported signaling effects--could be an explanation to its beneficial effects observed in vivo.


Asunto(s)
Antioxidantes/farmacología , Ácidos Cafeicos/farmacología , Radicales Libres/química , Hierro/química , Peroxidación de Lípido/efectos de los fármacos , Animales , Membrana Celular/metabolismo , Desoxirribosa/química , Espectroscopía de Resonancia por Spin del Electrón , Radical Hidroxilo/química , Quelantes del Hierro/química , Compuestos de Hierro/química , Masculino , Oxidación-Reducción/efectos de los fármacos , Ratas , Ratas Wistar
15.
Environ Toxicol ; 30(8): 865-76, 2015 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-24458998

RESUMEN

The aim of this study was to evaluate the antioxidant activities of diethyl ether (DEE) and methanol (M) extracts from brown alga Padina boergesenii using in vitro and in vivo antioxidant assay, which may help to relate the antioxidant properties with the possible outline of its ameliorative effect. M extract showed higher radical scavenging activity through ferric reducing antioxidant power 139.11 µmol tannic acid equivalent/g; DPPH 71.32 ± 0.56%; deoxyribose radical 88.31 ± 0.47%, and total antioxidant activity 0.47 ± 0.02 mg ascorbic acid equivalents/g. Oxidative red blood cell (RBC) hemolysis inhibition rate was significantly higher in M extract (150 mg/kg body weight) in reference to total phenolic content (r = 0.935). Rats administered with DEE and M extracts (150 mg/kg body weight) for seven days before the administration of ferric nitrilotriacetate (9 mg of Fe/mg/kg bodyweight). Rats pretreated with extracts significantly changed the level of renal microsomal lipid peroxidation, glutathione, and antioxidant enzymes in post-mitochondrial supernatant (P < 0.05). Ameliorative effect of extracts against renal oxidative damage was evident in rat kidney through changes in necrotic and epithelial cells. HPTLC technique has identified the presence of rutin with reference to retardation factor (Rf ) in both the extracts. These findings support the source of polyphenols (rutin) from P. boergesenii had potent antioxidant activity; further work on isolation of bioactive compounds can be channeled to develop as a natural antioxidant.


Asunto(s)
Antioxidantes/farmacología , Compuestos Férricos/antagonistas & inhibidores , Compuestos Férricos/toxicidad , Radicales Libres/toxicidad , Hemólisis/efectos de los fármacos , Enfermedades Renales/inducido químicamente , Enfermedades Renales/prevención & control , Ácido Nitrilotriacético/análogos & derivados , Estrés Oxidativo/efectos de los fármacos , Phaeophyceae/química , Extractos Vegetales/farmacología , Polifenoles/farmacología , Animales , Desoxirribosa/química , Desoxirribosa/farmacología , Células Epiteliales/efectos de los fármacos , Femenino , Técnicas In Vitro , Enfermedades Renales/metabolismo , Microsomas/efectos de los fármacos , Necrosis , Ácido Nitrilotriacético/antagonistas & inhibidores , Ácido Nitrilotriacético/toxicidad , Ratas , Ratas Wistar , Rutina/análisis , Taninos/farmacología
16.
Antimicrob Agents Chemother ; 58(12): 7056-71, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25224013

RESUMEN

In the absence of universally available antiretroviral (ARV) drugs or a vaccine against HIV-1, microbicides may offer the most immediate hope for controlling the AIDS pandemic. The most advanced and clinically effective microbicides are based on ARV agents that interfere with the earliest stages of HIV-1 replication. Our objective was to identify and characterize novel ARV-like inhibitors, as well as demonstrate their efficacy at blocking HIV-1 transmission. Abasic phosphorothioate 2' deoxyribose backbone (PDB) oligomers were evaluated in a variety of mechanistic assays and for their ability to inhibit HIV-1 infection and virus transmission through primary human cervical mucosa. Cellular and biochemical assays were used to elucidate the antiviral mechanisms of action of PDB oligomers against both lab-adapted and primary CCR5- and CXCR4-utilizing HIV-1 strains, including a multidrug-resistant isolate. A polarized cervical organ culture was used to test the ability of PDB compounds to block HIV-1 transmission to primary immune cell populations across ectocervical tissue. The antiviral activity and mechanisms of action of PDB-based compounds were dependent on oligomer size, with smaller molecules preventing reverse transcription and larger oligomers blocking viral entry. Importantly, irrespective of molecular size, PDBs potently inhibited virus infection and transmission within genital tissue samples. Furthermore, the PDB inhibitors exhibited excellent toxicity and stability profiles and were found to be safe for vaginal application in vivo. These results, coupled with the previously reported intrinsic anti-inflammatory properties of PDBs, support further investigations in the development of PDB-based topical microbicides for preventing the global spread of HIV-1.


Asunto(s)
Cuello del Útero/efectos de los fármacos , VIH-1/efectos de los fármacos , Oligonucleótidos Fosforotioatos/farmacología , Inhibidores de la Transcriptasa Inversa/farmacología , Transcripción Reversa/efectos de los fármacos , Internalización del Virus/efectos de los fármacos , Animales , Cuello del Útero/virología , Desoxirribosa/química , Células Epiteliales/efectos de los fármacos , Células Epiteliales/virología , Femenino , Expresión Génica , VIH-1/enzimología , VIH-1/genética , VIH-1/crecimiento & desarrollo , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Membrana Mucosa/efectos de los fármacos , Membrana Mucosa/virología , Técnicas de Cultivo de Órganos , Oligonucleótidos Fosforotioatos/síntesis química , Receptores CCR5/genética , Receptores CCR5/metabolismo , Receptores CXCR4/antagonistas & inhibidores , Inhibidores de la Transcriptasa Inversa/síntesis química , Motilidad Espermática/efectos de los fármacos , Relación Estructura-Actividad , Vagina/efectos de los fármacos , Vagina/virología
17.
J Mol Model ; 20(5): 2221, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24810462

RESUMEN

Modeling proton-induced damage in biological systems, in particular in DNA building blocks, is of major concern in studies on cancer proton therapy. This is indeed an extremely complex process and analysis of the mechanism at the molecular level is of crucial interest. Such collision reactions of protons on biological targets induce different reactions: excitation and ionization of the biomolecule, fragmentation of the ionized species, and charge transfer from the projectile ion toward the biomolecular target. In order to have an insight into such mechanisms, we have performed a theoretical approach of two of the most important steps, the fragmentation and the charge transfer processes. For that purpose, we have considered collision of protons with isolated 2-deoxy-D-ribose by means of ab-initio molecular dynamics and quantum chemistry molecular methods. The conformation of the sugar moiety has been analyzed and appears to induce important effects, in particular different fragmentation patterns have been pointed out with regard to the conformation, and significant variations of the charge transfer cross sections have been exhibited.


Asunto(s)
Daño del ADN , Desoxirribosa/química , Modelos Químicos , Modelos Moleculares , Simulación de Dinámica Molecular , Protones , Conformación de Carbohidratos , Transferencia de Energía , Conformación de Ácido Nucleico , Teoría Cuántica , Relación Estructura-Actividad
18.
Int J Radiat Biol ; 90(6): 446-58, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24547911

RESUMEN

PURPOSE: This article reviews the early history of ionizing radiation-induced sugar damage in DNA in dedication to Prof. Clemens von Sonntag, who recently passed away. It covers the time between 1968 and 1978, during which most of the work on the ionizing radiation-induced damage to polyalcohols, carbohydrates and the 2'-deoxyribose moiety in DNA was performed. Methodologies using gas chromatography-mass spectrometry (GC-MS) were developed to identify and quantify the radiation-induced products that had previously remained elusive. Products were identified by GC-MS either directly or after reduction of samples with NaBH(4) or NaBD(4). Incorporation of deuterium atoms by NaBD(4)-reduction facilitated the identification of aldehyde, keto, carboxyl and deoxy groups in the molecules. Numerous products of a polyalcohol and carbohydrates were identified and quantified. Mechanisms of product formation were proposed. Several products of the 2'-deoxyribose moiety in DNA were identified, indicating that they were released from DNA strand, not bound to it. Alkali labile sites and products still remaining within DNA or bound to DNA as end groups were also elucidated by first reducing irradiated samples with NaBD(4) followed by alkali treatment and GC-MS analysis. CONCLUSION: The knowledge of the products of the 2'-deoxyribose moiety in DNA led to the first mechanistic understanding of various pathways of hydroxyl radical-induced DNA strand breakage. To this date, some of these mechanisms still remain the most-widely studied mechanisms of DNA damage. Prof. von Sonntag's contributions to the understanding of the radiation chemistry of carbohydrates and DNA helped shape this field of science for years to come.


Asunto(s)
Daño del ADN , ADN/historia , Radioquímica/historia , ADN/química , ADN/efectos de la radiación , Roturas del ADN , Desoxirribosa/química , Desoxirribosa/efectos de la radiación , Eritritol/química , Eritritol/efectos de la radiación , Rayos gamma/efectos adversos , Cromatografía de Gases y Espectrometría de Masas , Alemania , Historia del Siglo XX , Modelos Químicos
19.
J Chem Phys ; 140(4): 044330, 2014 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-25669546

RESUMEN

Carbohydrates (2-deoxyribose, ribose, and xylose) and nucleotides (adenosine-, cytidine-, guanosine-, and uridine-5(')-monophosphate) are generated in the gas phase, and ionized with vacuum ultraviolet photons (VUV, 118.2 nm). The observed time of flight mass spectra of the carbohydrate fragmentation are similar to those observed [J.-W. Shin, F. Dong, M. Grisham, J. J. Rocca, and E. R. Bernstein, Chem. Phys. Lett. 506, 161 (2011)] for 46.9 nm photon ionization, but with more intensity in higher mass fragment ions. The tendency of carbohydrate ions to fragment extensively following ionization seemingly suggests that nucleic acids might undergo radiation damage as a result of carbohydrate, rather than nucleobase fragmentation. VUV photoionization of nucleotides (monophosphate-carbohydrate-nucleobase), however, shows that the carbohydrate-nucleobase bond is the primary fragmentation site for these species. Density functional theory (DFT) calculations indicate that the removed carbohydrate electrons by the 118.2 nm photons are associated with endocyclic C-C and C-O ring centered orbitals: loss of electron density in the ring bonds of the nascent ion can thus account for the observed fragmentation patterns following carbohydrate ionization. DFT calculations also indicate that electrons removed from nucleotides under these same conditions are associated with orbitals involved with the nucleobase-saccharide linkage electron density. The calculations give a general mechanism and explanation of the experimental results.


Asunto(s)
Carbohidratos/química , Iones/química , Nucleótidos/química , Rayos Ultravioleta , Vacio , Desoxirribosa/química , Electrones , Espectrometría de Masas , Modelos Químicos , Procesos Fotoquímicos , Fotones
20.
J Phys Chem A ; 118(33): 6326-32, 2014 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-24093626

RESUMEN

Modeling-induced radiation damage in biological systems, in particular, in DNA building blocks, is of major concern in cancer therapy studies. Ion-induced charge-transfer dynamics may indeed be involved in proton and hadrontherapy treatments. We have thus performed a theoretical approach of the charge-transfer dynamics in collision of C(4+) ions and protons with isolated 2-deoxy-D-ribose in a wide collision energy range by means of ab initio quantum chemistry molecular methods. The comparison of both projectile ions has been performed with regard to previous theoretical and experimental results. The charge transfer appears markedly less efficient with the 2-deoxy-D-ribose target than that with pyrimidine nucleobases, which would induce an enhancement of the fragmentation process in agreement with experimental measurements. The mechanism has been analyzed with regard to inner orbital excitations, and qualitative tendencies have been pointed out for studies on DNA buiding block damage.


Asunto(s)
Desoxirribosa/química , Protones , Teoría Cuántica , ADN/química , Daño del ADN , Desoxirribosa/aislamiento & purificación
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