Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 20
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
ACS ES T Water ; 3(8): 2009-2023, 2023 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-37614778

RESUMEN

Iodine (I2) in the form of iodide ions (I-) is an essential chemical element in the human body. Iodine is a nonmetal that belongs to the VIIA group (halogens) in the periodic table. Over the last couple of centuries, the exponential growth of human society triggered by industrialization coincided with the use of iodine in a wide variety of applications, including chemical and biological processes. However, through these processes, the excess amount of iodine eventually ends up contaminating soil, underground water, and freshwater sources, which results in adverse effects. It enters the food chain and interferes with biological processes with serious physiological consequences in all living organisms, including humans. Existing removal techniques utilize different materials such as metal-organic frameworks, layered double hydroxides, ion-exchange resins, silver, polymers, bismuth, carbon, soil, MXenes, and magnetic-based materials. From our literature survey, it was clear that absorption techniques are the most frequently experimented with. In this Review, we have summarized current advancements in the removal of iodine and iodide from human-made contaminated aqueous waste.

2.
Amino Acids ; 55(7): 939-946, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37294378

RESUMEN

A divergent, enantioselective synthetic strategy is reported to produce the non-proteinogenic, biologically active natural amino acids norvaline, 5-hydroxy-4-oxo-L-norvaline, and ɣ-oxonorvaline. These were synthesized in good yields (45-75%) from the common starting material (S)-allylglycine obtained by asymmetric transfer allylation of glycine Schiff base using the Corey catalyst derived from cinchonidine in more than 97% enantiomeric excess.


Asunto(s)
Aminoácidos , Valina , Aminoácidos/química , Glicina/química , Alilglicina/química , Catálisis , Estereoisomerismo
3.
Polymers (Basel) ; 14(21)2022 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-36365647

RESUMEN

The structural modification of biopolymers is a current strategy to develop materials with biomedical applications. Silk fibroin is a natural fiber derived from a protein produced by the silkworm (Bombyx mori) with biocompatible characteristics and excellent mechanical properties. This research reports the structural modification of silk fibroin by incorporating polyaniline chain grafts through a one-pot process (esterification reaction/oxidative polymerization). The structural characterization was achieved by 1H-NMR and FT-IR. The morphology was studied by scanning electron microscopy and complemented with thermogravimetric analysis to understand the effect of the thermal stability at each step of the modification. Different fibroin silk (Fib): polyaniline (PAni) mass ratios were evaluated. From this evaluation, it was found that a Fib to PAni ratio of at least 1 to 0.5 is required to produce electroactive polyaniline, as observed by UV-vis and CV. Notably, all the fibroin-g-PAni systems present low cytotoxicity, making them promising systems for developing biocompatible electrochemical sensors.

4.
Foods ; 11(14)2022 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-35885261

RESUMEN

The inclusion of natural ingredients to preserve meat and meat products has increased in recent years. This study evaluated rosemary (REO) and garlic essential oils (GEO) as well as chipotle pepper oleoresin (CPO), alone or in combination, as preservatives on beef hamburgers (BH). Six treatments were evaluated: T1 (control, without additives), T2 (GEO 1%), T3 (REO 1%), T4 (CPO 0.5%), T5 (GEO 1% + CPO 0.5%) and T6 (REO 1% + CPO 0.5%). The microbiological quality, physicochemical characteristics, sensory evaluation, and lipid oxidation of hamburgers were evaluated. REO, GEO and CPO limited the growth of aerobic microorganisms, S. aureus, Salmonella spp., B. thermosphacta, moulds and yeasts, lactic acid bacteria and coliforms (p < 0.05); however, this effect depended on time. Furthermore, lipid oxidation decreased significantly (p < 0.5) in all treatments, except for T5 (GEO 1% + CPO 0.5%). Regarding sensory acceptance, consumers preferred BH with GEO in terms of colour, odour, flavour and overall appearance (p < 0.05). It is concluded that REO, GEO and CPO, alone or in combination, improve microbiological quality and inhibit the lipid oxidation of BH.

5.
Int J Mol Sci ; 23(15)2022 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-35897666

RESUMEN

In this research, a brush-like polyaniline (poly(2-acrylamide-2-methyl-1-propanesulfonate)-g-polyaniline)-b-poly(N-vinylcarbazole) (BL PAni) was developed as a strategy to overcome the limited processability and dedoping above pH 4 of conventional polyaniline (PAni). For the BL PAni synthesis, RAFT polymerization (homopolymer), RAFT-mediated surfactant-free emulsion polymerization (block copolymer), and interfacial oxidative polymerization were applied to graft the PAni chains. NMR and FT-IR spectroscopies were performed to confirm the structural elucidation of the reaction pathways, while the thermal properties were analyzed by TGA and DSC. Notably, the BL PAni presents absorption throughout the visible region and up to the near-infrared, showing dedoping resistance at up to 80 °C and at a neutral pH. The absorption range of the BL PAni, block copolymer, and homopolymer were studied by UV-Vis spectroscopy in solid-state and dispersion/solution, highlighting BL PAni and poly(anilinium 2-acrylamide-2-methyl-1-propanesulfonate)-b-poly(N-vinylcarbazole) (PAAMP-b-PVK) due to the π-stacking between the anilinium and carbazole groups. The cyclic voltammetry confirmed the persistence of electroactivity at a pH near 7.


Asunto(s)
Acrilamidas , Polímeros , Compuestos de Anilina , Concentración de Iones de Hidrógeno , Espectroscopía Infrarroja por Transformada de Fourier , Temperatura
6.
Nanomaterials (Basel) ; 12(9)2022 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-35564174

RESUMEN

Carbon nanotubes (CNTs) have been proposed as nanovehicles for drug or antigen delivery since they can be functionalized with different biomolecules. For this purpose, different types of molecules have been chemically bonded to CNTs; however, this method has low efficiency and generates solvent waste. Candida antarctica lipase is an enzyme that, in an organic solvent, can bind a carboxylic to a hydroxyl group by esterase activity. The objective of this work was to functionalize purified CNTs with insulin as a protein model using an immobilized lipase of Candida antarctica to develop a sustainable functionalization method with high protein attachment. The functionalized CNTs were characterized by scanning electron microscope (SEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzymatic functionalization of insulin on the surface of the CNTs was found to have an efficiency of 21%, which is higher in conversion and greener than previously reported by the diimide-activated amidation method. These results suggest that enzymatic esterification is a convenient and efficient method for CNT functionalization with proteins. Moreover, this functionalization method can be used to enhance the cellular-specific release of proteins by lysosomal esterases.

7.
Polymers (Basel) ; 14(3)2022 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-35160621

RESUMEN

Renewable polymers possess the potential to replace monomers from petrochemical sources. The design and development of polymeric materials from sustainable materials are a technological challenge. The main objectives of this study were to study the microstructure of copolymers based on itaconic acid (IA), di-n-butyl itaconate (DBI), and lauryl methacrylate (LMA); and to explore and to evaluate these copolymers as pressure-sensitive adhesives (PSA). The copolymer synthesis was carried out through batch emulsion radical polymerization, an environmentally friendly process. IA was used in a small fixed amount as a functional comonomer, and LMA was selected due to low glass transition temperature (Tg). The structure of synthesized copolymers was studied by FTIR, 1H-NMR, Soxhlet extraction, and molecular weight analyses by GPC. Furthermore, the viscoelastic and thermal properties of copolymer films were characterized by DMA, DSC, and TGA. The single Tg displayed by the poly(DBI-LMA-IA) terpolymers indicates that statistical random composition copolymers were obtained. Moreover, FTIR and NMR spectra confirm the chemical structure and composition. It was found that a cross-linked microstructure and higher molecular weight are observed with an increase of LMA in the feed led. The Tg and modulus (G') of the copolymers film can be tuned with the ratio of DBI:LMA providing a platform for a wide range of applications as a biobased alternative to produce waterborne PSA.

8.
Genes (Basel) ; 13(2)2022 01 20.
Artículo en Inglés | MEDLINE | ID: mdl-35205224

RESUMEN

Glutathione peroxidase 3 (GPx3) is the only extracellular selenoprotein (Sel) that enzymatically reduces H2O2 to H2O and O2. Two GPx3 (CqGPx3) cDNAs were characterized from crayfish Cherax quadricarinatus. The nerve cord CqGPx3a isoform encodes for a preprotein containing an N-terminal signal peptide of 32 amino acid residues, with the mature Sel region of 192 residues and a dispensable phosphorylation domain of 36 residues. In contrast, the pereiopods CqGPx3b codes for a precursor protein with 19 residues in the N-terminal signal peptide, then the mature 184 amino acid residues protein and finally a Pro-rich peptide of 42 residues. CqGPx3 are expressed in cerebral ganglia, pereiopods and nerve cord. CqGPx3a is expressed mainly in cerebral ganglia, antennulae and nerve cord, while CqGPx3b was detected mainly in pereiopods. CqGPx3a expression increases with high temperature and hypoxia; meanwhile, CqGPx3b is not affected. We report the presence and differential expression of GPx3 isoforms in crustacean tissues in normal conditions and under stress for high temperature and hypoxia. The two isoforms are tissue specific and condition specific, which could indicate an important role of CqGPx3a in the central nervous system and CqGPx3b in exposed tissues, both involved in different responses to environmental stressors.


Asunto(s)
Astacoidea , Selenio , Aminoácidos/genética , Animales , Astacoidea/genética , Astacoidea/metabolismo , Clonación Molecular , ADN Complementario/genética , Peróxido de Hidrógeno/metabolismo , Hipoxia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Señales de Clasificación de Proteína/genética , Selenio/metabolismo , Temperatura
9.
Pharmaceuticals (Basel) ; 14(10)2021 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-34681221

RESUMEN

Ketoprofen is a commercially available drug sold as a racemic mixture that belongs to the family of non-steroidal anti-inflammatory drugs known as profens. It has been demonstrated (in vitro) that (S)-ketoprofen is around 160 times more potent than its enantiomer (R)-ketoprofen, while accumulation of (R)-ketoprofen can cause serious side effects, such as dyspepsia, gastrointestinal ulceration/bleeding, pain, salt and fluid retention, and hypertension. In this work, four commercially available lipases were systematically assessed. Parameters such as conversion, enantiomeric excess, and enantioselectivity were considered. Among them, and by evaluating lipase load, temperature, solvent, and alcohol, Candida rugosa lipase exhibited the best results in terms of enantioselectivity E = 185 ((S)-enantiopreference) with esterification conversions of c = 47% (out of 50%) and enantiomeric excess of 99%. The unreacted (R)-enantiomer was recovered by liquid-liquid extraction and racemized under basic media, which was recycled as starting material. Finally, the (S)-alkyl ketoprofen ester was successfully enzymatically hydrolyzed to the desired (S)-ketoprofen with c = 98.5% and 99% ee. This work demonstrated the benefit and efficiency of using Candida rugosa lipase to kinetically resolve racemic ketoprofen by an environmentally friendly protocol and with the recycling of the undesired (R)-ketoprofen.

10.
Polymers (Basel) ; 13(14)2021 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-34301106

RESUMEN

The development of anilinium 2-acrylamide-2-methyl-1-propanesulfonate (Ani-AMPS) monomer, confirmed by 1H NMR, 13C NMR, and FTIR, is systematically studied. Ani-AMPS contains two polymerizable functional groups, so it was submitted to selective polymerization either by free-radical or oxidative polymerization. Therefore, poly(anilinium 2-acrylamide-2-methyl-1-propanesulfonic) [Poly(Ani-AMPS)] and polyaniline doped with 2-acrylamide-2-methyl-1-propanesulfonic acid [PAni-AMPS] can be obtained. First, the acrylamide polymer, poly(Ani-AMPS), favored the π-stacking of the anilinium group produced by the inter- and intra-molecular interactions and was studied utilizing 1H NMR, 13C NMR, FTIR, and UV-Vis-NIR. Furthermore, poly(Ani-AMPS) fluorescence shows quenching in the presence of Fe2+ and Fe3+ in the emission spectrum at 347 nm. In contrast, the typical behavior of polyaniline is observed in the cyclic voltammetry analysis for PAni-AMPS. The optical properties also show a significant change at pH 4.4. The PAni-AMPS structure was corroborated through FTIR, while the thermal properties and morphology were analyzed utilizing TGA, DSC (except PAni-AMPS), and FESEM.

11.
Acta Crystallogr E Crystallogr Commun ; 77(Pt 2): 130-133, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-33614140

RESUMEN

The title compound (E)-1,3-dimethyl-2-[3-(4-nitro-phen-yl)triaz-2-enyl-idene]-2,3-di-hydro-1H-imidazole, C11H12N6O2, has monoclinic (C2/c) symmetry at 100 K. This triazene derivative was synthesized by the coupling reaction of 1,3-di-methyl-imidazolium iodide with 1-azido-4-nitro benzene in the presence of sodium hydride (60% in mineral oil) and characterized by 1H NMR, 13C NMR, IR, mass spectrometry, and single-crystal X-ray diffraction. The mol-ecule consists of six-membered and five-membered rings, which are connected by a triazene moiety (-N=N-N-). In the solid-state, the mol-ecule is found to be planar due to conjugation throughout the mol-ecule. The extended structure shows two layers of mol-ecules, which present weak inter-molecular inter-actions that facilitate the stacked arrangement of the mol-ecules forming the extended structure. Furthermore, there are several weak pseudo-cyclical inter-actions between the nitro oxygen atoms and symmetry-adjacent H atoms, which help to arrange the mol-ecules.

12.
Environ Sci Technol ; 54(19): 12511-12520, 2020 10 06.
Artículo en Inglés | MEDLINE | ID: mdl-32902265

RESUMEN

The electrochemical oxidation of sulfite ions offers encouraging advantages for large-scale hydrogen production, while sulfur dioxide emissions can be effectively used to obtain value-added byproducts. Herein, the performance and stability during sulfite electrolysis under alkaline conditions are evaluated. Nickel foam (NF) substrates were functionalized as the anode and cathode through electrochemical deposition of palladium and chemical oxidation to carry out the sulfite electro-oxidation and hydrogen evolution reactions, respectively. A combined analytical approach in which a robust electrochemical flow cell was coupled to different in situ and ex situ measurements was successfully implemented to monitor the activity and stability during electrolysis. Overall, satisfactory sulfite conversion and hydrogen production efficiencies (>90%) at 10 mA·cm-2 were mainly attributed to the use of NF in three-dimensional electrodes with a large surface area and enhanced mass transfer. Furthermore, stabilization processes associated with electrochemical dissolution and sulfur crossover through the membrane induced specific changes in the chemical and physical properties of the electrodes after electrolysis. This study demonstrates that NF-based electrocatalysts can be incorporated in an efficient electrochemical flow cell system for sulfite electrolysis and hydrogen production, with potential applications at a large scale.


Asunto(s)
Electrólisis , Níquel , Electrodos , Hidrógeno , Sulfitos
13.
Nanomaterials (Basel) ; 10(2)2020 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-32102423

RESUMEN

Carbon nanotubes (CNTs) are nanomaterials with multiple possible uses as drug carriers or in nanovaccine development. However, the toxicity of CNTs administered intravenously in in vivo models has not been fully described to date. This work aimed to evaluate the toxic effect of pristine multi-walled CNTs (UP-CNTs), purified (P-CNTs), or CNTs functionalized with fluorescein isothiocyanate (FITC-CNTs) administered by intravenous injection in BALB/c mice. Biochemical and histopathological parameters were analyzed at 1, 14, 29, and 60 days post-exposure. Pristine CNTs were the most toxic nanoparticles in comparison with P-CNTs or FITC-CNTs, increasing serum AST (≈ 180%), ALT (≈ 300%), and LDH (≈ 200%) levels at one day post-exposure. The urea/creatinine ratio suggested pre-renal injury at the 14th day accompanied of extensive lesions in kidneys, lungs, and liver. Biochemical and histological findings in mice exposed to P-CNTs had not significant differences compared to the controls. A lower toxic effect was detected in animals exposed to FITC-CNTs which was attributable to FITC toxicity. These results demonstrate that the purification process of CNTs reduces in vivo toxicity, and that toxicity in functionalized CNTs is dependent on the functionalized compound. Therefore, P-CNTs are postulated as potential candidates for safe biomedical applications using an intravenous pathway.

14.
J Anal Methods Chem ; 2019: 8150678, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31263626

RESUMEN

Lead and chromium contamination represents one of the most serious problems in the aquatic environments. The aim of this work was to develop and validate an accurate, sensitivity, and rapid method for the simultaneous determination of Pb and Cr at trace levels in tissues and fat of marine organisms such as turtle (Chelonia mydas), shark (Rhizoprionodon terraenovae), and dolphin (Tursiops truncatus), utilizing the total reflection X-Ray fluorescence (TXRF) spectroscopy. Working solutions were prepared in 10 mL of a solution 0.005 mol·L-1 EDTA and 1 mol·L-1 HNO3. In order to correct possible instrument drifts, 20 µg·L-1 of gallium was used as internal standard (IS). The results showed that TXRF method was linear over the concentration ranges of 5.242-100 µg·L-1 for Pb and 2.363-100 µg·L-1 for Cr. Limits of detection (LOD) achieved were 1.573 and 0.709 µg·L-1 for Pb and Cr, respectively, while limits of quantification achieved were 5.242 µg·L-1 for Pb and 2.363 µg·L-1 for Cr. The validated method was accurate and precise enough for determination of these heavy metals in samples of marine organisms as indicated by acceptable values of recovery between 90-101%. In addition, a certified reference material (BCR-279, sea lettuce) and a Centrum tablet were satisfactory analyzed, and the T-test for comparison of means revealed that there were no significant differences at the 95% confidence level between the values obtained with the proposed TXRF method and the certificated values. The repeatability of the method, expressed as relative standard deviation (RSD), was 5.1% and 4%, for Pb and Cr, respectively. In addition, other features of the developed method were a low sample volume of 10 µL, and the sample frequency achieved was 20 h-1.

15.
BMC Complement Altern Med ; 19(1): 153, 2019 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-31262287

RESUMEN

BACKGROUND: Rhus trilobata Nutt. (Anacardiaceae) (RHTR) is a plant of Mexico that is traditionally used as an alternative treatment for several types of cancer. However, the phytochemical composition and potential toxicity of this plant have not been evaluated to support its therapeutic use. Therefore, this study aimed to evaluate the biological activity of RHTR against colorectal adenocarcinoma cells, determine its possible acute toxicity, and analyze its phytochemical composition. METHODS: The traditional preparation was performed by decoction of stems in distilled water (aqueous extract, AE), and flavonoids were concentrated with C18-cartridges and ethyl acetate (flavonoid fraction, FF). The biological activity was evaluated by MTT viability curves and the TUNEL assay in colorectal adenocarcinoma (CACO-2), ovarian epithelium (CHO-K1) and lung/bronchus epithelium (BEAS-2B) cells. The toxicological effect was determined in female BALB/c mice after 24 h and 14 days of intraperitoneal administration of 200 mg/kg AE and FF, respectively. Later, the animals were sacrificed for histopathological observation of organs and sera obtained by retro-orbital bleeding for biochemical marker analysis. Finally, the phytochemical characterization of AE and FF was conducted by UPLC-MSE. RESULTS: In the MTT assays, AE and FF at 5 and 18 µg/mL decreased the viability of CACO-2 cells compared with cells treated with vehicle or normal cells (p ≤ 0.05, ANOVA), with changes in cell morphology and the induction of apoptosis. Anatomical and histological analysis of organs did not reveal important pathological lesions at the time of assessment. Additionally, biochemical markers remained normal and showed no differences from those of the control group after 24 h and 14 days of treatment (p ≤ 0.05, ANOVA). Finally, UPLC-MSE analysis revealed 173 compounds in AE-RHTR, primarily flavonoids, fatty acids and phenolic acids. The most abundant compounds in AE and FF were quercetin and myricetin derivates (glycosides), methyl gallate, epigallocatechin-3-cinnamate, ß-PGG, fisetin and margaric acid, which might be related to the anticancer properties of RHTR. CONCLUSION: RHTR exhibits biological activity against cancer cells and does not present adverse toxicological effects during its in vivo administration, supporting its traditional use.


Asunto(s)
Antineoplásicos Fitogénicos/análisis , Rhus/química , Animales , Antioxidantes/análisis , Células CHO , Células CACO-2 , Cricetulus , Ensayos de Selección de Medicamentos Antitumorales , Femenino , Flavonoides/análisis , Humanos , Medicina Tradicional , México , Ratones Endogámicos BALB C , Fitoterapia , Extractos Vegetales/análisis , Extractos Vegetales/uso terapéutico , Extractos Vegetales/toxicidad , Polifenoles/análisis , Rhus/toxicidad
16.
Chem Cent J ; 12(1): 39, 2018 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-29644551

RESUMEN

Nowadays the industrial chemistry reactions rely on green technologies. Enzymes as lipases are increasing its use in diverse chemical processes. Epoxidized fatty acid methyl esters obtained from transesterification of vegetable oils have recently found applications as polymer plasticizer, agrochemical, cosmetics, pharmaceuticals and food additives. In this research article, grapeseed, avocado and olive oils naturally containing high percents of mono and poly unsaturations were used as starting materials for the production of unsaturated fatty acid methyl esters. The effect of lauric acid as an active oxygen carrier was studied on epoxidation reactions where unsaturated fatty acid methyl esters were converted to epoxy fatty acid methyl esters using immobilized Candida antarctica Lipase type B as catalyst and hydrogen peroxide as oxygen donor at mild temperature and pressure conditions. After this study it was confirmed by 1H NMR, 13C NMR and GC-MS that the addition of lauric acid to the enzymatic reaction is unnecessary to transform the alkenes in to epoxides. It was found that quantitative conversions were possible in despite of a carboxylic acid absence.

17.
Chem Cent J ; 9: 46, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26361495

RESUMEN

BACKGROUND: Malathion (R,S)-diethyl-2-[(dimethoxyphosphorothioyl)sulfanyl]butanedioate is a chiral organophosphorus compound used widely as pesticide for suppression of harmful insects such as mosquitoes. It is well known that in biological systems (R)-malathion is the active enantiomer, therefore a sustainable approach could be the use of only the biologically active enantiomer. The resolution of the commercial racemic mixture to obtain the pure active enantiomer combined with a recycling of the undesired enantiomer through a racemization process could be an attractive alternative to reduce the environmental impact of this pesticide. Thus, this work evaluates the use of four commercially available lipases for enantioselective hydrolysis and separation of malathion enantiomers from the commercial racemic mixture. RESULTS: Several lipases were methodologically assessed, considering parameters such as enzyme concentration, temperature and reaction rates. Among them, Candida rugosa lipase exhibited the best performance, in terms of enantioselectivity, E = 185 (selective to the (S)-enantiomer). In this way, the desired unreacted (R)-enantiomer was recovered in a 49.42 % yield with an enantiomeric excess of 87 %. The monohydrolized (S)-enantiomer was recovered and racemized in basic media, followed by esterification to obtain the racemic malathion, which was recycled. In this way, an enantioenriched mixture of (R)-malathion was obtained with a conversion of 65.80 % considering the recycled (S)-enantiomer. CONCLUSION: This work demonstrated the feasibility of exploiting Candida rugosa lipase to kinetically resolve racemic malathion through an environmentally friendly recycling of the undesired (S)-enantiomer. Graphical AbstractLipase catalyzed enantioselective resolution of (R)-malathion in aqueous solvent.

18.
Molecules ; 20(5): 8654-65, 2015 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-26007172

RESUMEN

A palladium mediated synthesis of a common synthon for the syntheses of antioxidant analogues of naturally occurring salvianolic acids is presented. The synthetic route may be used to obtain analogues with a balanced lipophilicity/hydrophilicity which may result in potentially interesting LDL antioxidants for the prevention of cardiovascular diseases.


Asunto(s)
Alquenos/química , Antioxidantes/síntesis química , Benzofuranos/síntesis química , Lipoproteínas LDL/metabolismo , Polifenoles/química , Alquenos/síntesis química , Alquenos/metabolismo , Antioxidantes/química , Benzofuranos/química , Benzofuranos/metabolismo , Medicina Tradicional China , Estrés Oxidativo , Paladio/química , Polifenoles/síntesis química , Polifenoles/metabolismo
19.
Molecules ; 19(1): 352-66, 2013 Dec 30.
Artículo en Inglés | MEDLINE | ID: mdl-24381052

RESUMEN

A series of pyrene-fullerene C60 dyads bearing pyrene units (PyFC12, PyFPy, Py2FC12 and PyFN) were synthesized and characterized. Their optical properties were studied by absorption and fluorescence spectroscopies. Dyads were designed in this way because the pyrene moeities act as light-harvesting molecules and are able to produce "monomer" (PyFC12) or excimer emission (PyFPy, Py2FC12 and PyFN). The fluorescence spectra of the dyads exhibited a significant decrease in the amount of pyrene monomer and excimer emission, without the appearance of a new emission band due to fullerene C60. The pyrene fluorescence quenching was found to be almost quantitative, ranging between 96%-99% depending on the construct, which is an indication that energy transfer occurred from one of the excited pyrene species to the fullerene C60.


Asunto(s)
Fulerenos/química , Pirenos/química , Absorción , Técnicas de Química Sintética , Luz , Espectrometría de Fluorescencia
20.
Biotechnol J ; 4(8): 1222-4, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19455529

RESUMEN

Ibuprofen belongs to the non-steroidal anti-inflammatory drug (NSAID) family known as profens. Studies demonstrate that (S-ibuprofen is 160 times more potent than (R-ibuprofen in vitro, while the accumulation of (R-ibuprofen can cause serious side effects such as gastrointestinal pain. Candida rugosa lipase was used to enantioselectively esterify racemic ibuprofen with decan-1-ol and butan-1-ol in cyclohexane with an enantiomeric ratio (E) of 130 and 46, respectively, in up to 46% conversion. Separation by bulb-to-bulb distillation of (R)-ibuprofen and unreacted alcohol from the corresponding (S)-alkyl ibuprofen ester was possible for the decyl but not the butyl case. The enantioselective hydrolysis of (S)-alkyl ibuprofen esters with the same biocatalyst in aqueous phosphate buffer was twice as slow for the decyl alcohol versus the butyl example. The combined environmentally friendly enantioselective esterification and hydrolysis of ibuprofen insured the isolation of (S)-ibuprofen with a greater than 99% enantiomeric excess.


Asunto(s)
Antiinflamatorios no Esteroideos/química , Antiinflamatorios no Esteroideos/farmacología , Ibuprofeno/química , Ibuprofeno/farmacología , Alcoholes/química , Candida/enzimología , Catálisis , Química Farmacéutica/métodos , Ciclohexanos/farmacología , Relación Dosis-Respuesta a Droga , Ésteres , Hidrólisis , Cinética , Lipasa/química , Modelos Químicos , Dolor/etiología , Estereoisomerismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...