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An unprecedented approach for efficient synthesis of functionalized allylic gem-difluorides via catalytic fluorinative Meyer-Schuster-like rearrangement is disclosed. This transformation proceeded with readily accessible propargylic fluorides, and low-cost B-F reagents and electrophilic reagents by sulfide catalysis. A series of iodinated, brominated, and trifluoromethylthiolated allylic gem-difluorides that were difficult to access by other methods were facilely produced with a wide range of functional groups. Importantly, the obtained iodinated products could be incorporated into different drugs and natural products, and could be expediently converted into many other valuable gem-difluoroalkyl molecules as well. Mechanistic studies revealed that this reaction went through a regioselective fluorination of alkynes followed by a formal 1,3-fluorine migration under the assistance of the B-F reagents to give the desired products.
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Mitochondrial calcium overload is a crucial event in determining the fate of neuronal cell survival and death, implicated in pathogenesis of neurodegenerative diseases. One of the driving forces of calcium influx into mitochondria is mitochondria membrane potential (ΔΨm). Therefore, pharmacological manipulation of ΔΨm can be a promising strategy to prevent neuronal cell death against brain insults. Based on these issues, we investigated here whether nobiletin, a Citrus polymethoxylated flavone, prevents neurotoxic neuronal calcium overload and cell death via regulating basal ΔΨm against neuronal insult in primary cortical neurons and pure brain mitochondria isolated from rat cortices. Results demonstrated that nobiletin treatment significantly increased cell viability against glutamate toxicity (100 µM, 20 min) in primary cortical neurons. Real-time imaging-based fluorometry data reveal that nobiletin evokes partial mitochondrial depolarization in these neurons. Nobiletin markedly attenuated mitochondrial calcium overload and reactive oxygen species (ROS) generation in glutamate (100 µM)-stimulated cortical neurons and isolated pure mitochondria exposed to high concentration of Ca2+ (5 µM). Nobiletin-induced partial mitochondrial depolarization in intact neurons was confirmed in isolated brain mitochondria using a fluorescence microplate reader. Nobiletin effects on basal ΔΨm were completely abolished in K+-free medium on pure isolated mitochondria. Taken together, results demonstrate that K+ influx into mitochondria is critically involved in partial mitochondrial depolarization-related neuroprotective effect of nobiletin. Nobiletin-induced mitochondrial K+ influx is probably mediated, at least in part, by activation of mitochondrial K+ channels. However, further detailed studies should be conducted to determine exact molecular targets of nobiletin in mitochondria.
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The efficient regio- and stereoselective construction of tetrasubstituted alkenes is challenging and very important. For this purpose, we have developed an efficient approach to synthesize tetrasubstituted trifluoromethylthiolated alkenes from simple alkynes in excellent regio- and stereoselectivities by selenide-catalyzed multicomponent coupling. Using this method, trifluoromethylthiolated alkenyl triflates and arenes were achieved. In particular, the triflates could be further converted into carbofunctionalized alkenes by palladium-catalyzed cross-coupling reactions. Our method provides a new pathway for the construction of trifluoromethylthiolated tricarboalkenes. This work presents the first example of selenide-catalyzed trifluoromethylthiolation of alkynes and enables the challenging functionalizations of alkynes.
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Excessive microglial activation and subsequent neuroinflammation lead to synaptic loss and dysfunction as well as neuronal cell death, which are involved in the pathogenesis and progression of several neurodegenerative diseases. Thus, the regulation of microglial activation has been evaluated as effective therapeutic strategies. Although dieckol (DEK), one of the phlorotannins isolated from marine brown alga Ecklonia cava, has been previously reported to inhibit microglial activation, the molecular mechanism is still unclear. Therefore, we investigated here molecular mechanism of DEK via extracellular signal-regulated kinase (ERK), Akt and nicotinamide adenine dinuclelotide phosphate (NADPH) oxidase-mediated pathways. In addition, the neuroprotective mechanism of DEK was investigated in microglia-mediated neurotoxicity models such as neuron-microglia co-culture and microglial conditioned media system. Our results demonstrated that treatment of anti-oxidant DEK potently suppressed phosphorylation of ERK in lipopolysaccharide (LPS, 1 µg/ml)-stimulated BV-2 microglia. In addition, DEK markedly attenuated Akt phosphorylation and increased expression of gp91 (phox) , which is the catalytic component of NADPH oxidase complex responsible for microglial reactive oxygen species (ROS) generation. Finally, DEK significantly attenuated neuronal cell death that is induced by treatment of microglial conditioned media containing neurotoxic secretary molecules. These neuroprotective effects of DEK were also confirmed in a neuron-microglia co-culture system using enhanced green fluorescent protein (EGFP)-transfected B35 neuroblastoma cell line. Taken together, these results suggest that DEK suppresses excessive microglial activation and microglia-mediated neuronal cell death via downregulation of ERK, Akt and NADPH oxidase-mediated pathways.
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Two isostructural 1D coordination polymers {[Ln(OAc)2(H2O)(OBPT)]·3H2O}n (HOBPT = 4,6-bis(2-pyridyl)-1,3,5-triazin-2-ol, Ln = Eu(3+), 1; Tb(3+), 3) and two discrete complexes [Ln(OAc)2(DMF)2(OBPT)] (Ln = Eu(3+), 2; Tb(3+), 4) have been synthesized in H2O-MeOH or DMF solvents, respectively. Their structures were identified by powder X-ray diffraction. Single-crystal X-ray studies for complexes 1 and 2 revealed that the coordination geometries of the Eu(3+) ions are similar and can be described as a distorted tricapped trigonal prism with six oxygen atoms and three nitrogen atoms. The difference between them is that one aqua ligand and one oxygen atom from the OBPT ligand complete the coordination sphere in complex 1, whereas two DMF molecules complete the coordination sphere in complex 2. Interestingly, the solvent-mediated, reversible crystal-to-crystal transformation between them was achieved by immersing the crystalline samples in the corresponding solvent (H2O or DMF) or by exposing them to solvent vapor. Complex 1 shows a highly selective luminescence enhancement in response to DMF in comparison to that observed in response to other examined solvents such as acetone, ethyl acetate, ethanol, acetonitrile, methanol, and THF.
Asunto(s)
Elementos de la Serie de los Lantanoides/química , Compuestos Organometálicos/química , Polímeros/química , Cristalografía por Rayos X , Modelos Moleculares , Estructura Molecular , Compuestos Organometálicos/síntesis química , Solventes/químicaRESUMEN
Mitochondrial membrane potential (∆Ψm ) contributes to determining a driving force for calcium to enter the mitochondria. It has been demonstrated that even a small mitochondrial depolarization is sufficient to prevent mitochondrial calcium overload and the subsequent apoptosis. Therefore, mild mitochondrial depolarization has been recently evaluated as a novel mechanism of neuroprotection via inhibiting neurotoxic mitochondrial calcium overload during neuronal insults. In the present study, using both real-time recording and flow cytometric analyses of ∆Ψm , we demonstrated that ethanolic peel extract of Citrus sunki Hort. ex Tanaka (CPE) and its active compounds are capable of inducing a mild mitochondrial depolarization. Polymethoxylated flavones such as nobiletin and tangeretin were found as the active compounds responsible for CPE effects on ∆Ψm . Neuronal viability was significantly increased in a dose-dependent manner by CPE treatment in H2 O2 -stimulated HT-22 cells as an in vitro neuronal insult model. CPE treatment significantly inhibited H2 O2 -induced apoptotic processes such as chromatin condensation, caspase 3 activation and anti-poly (ADP-ribose) polymerase (PARP) cleavage. CPE treatment significantly blocked mitochondrial calcium overload in H2 O2 -stimulated HT-22 neurons as indicated by rhod-2 acetoxymethyl ester. Taken together, our findings suggest that CPE and its active compounds may be considered as promising neuroprotective agents via inducing a mild mitochondrial depolarization.
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Citrus/química , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Neuronas/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Extractos Vegetales/farmacología , Apoptosis , Calcio/metabolismo , Línea Celular , Flavonas/farmacología , Citometría de Flujo , Frutas/química , Humanos , Peróxido de Hidrógeno/farmacología , Mitocondrias/efectos de los fármacosRESUMEN
We propose a partial point cloud completion approach for scenes that are composed of multiple objects. We focus on pairwise scenes where two objects are in close proximity and are contextually related to each other, such as a chair tucked in a desk, a fruit in a basket, a hat on a hook and a flower in a vase. Different from existing point cloud completion methods, which mainly focus on single objects, we design a network that encodes not only the geometry of the individual shapes, but also the spatial relations between different objects. More specifically, we complete missing parts of the objects in a conditional manner, where the partial or completed point cloud of the other object is used as an additional input to help predict missing parts. Based on the idea of conditional completion, we further propose a two-path network, which is guided by a consistency loss between different sequences of completion. Our method can handle difficult cases where the objects heavily occlude each other. Also, it only requires a small set of training data to reconstruct the interaction area compared to existing completion approaches. We evaluate our method qualitatively and quantitatively via ablation studies and in comparison to the state-of-the-art point cloud completion methods.
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A growing body of evidence suggests that nobiletin (5,6,7,8,3',4'-hexamethoxy flavone) from the peel of citrus fruits, enhances the damaged cognitive function in disease animal models. However, the neuroprotective mechanism has not been clearly elucidated. Since nobiletin has shown anti-inflammatory effects in several tissues, we investigated whether nobiletin suppresses excessive microglial activation implicated in neurotoxicity in lipopolysaccharide (LPS)-stimulated BV-2 microglia cell culture models. Release of nitric oxide (NO), the major inflammatory mediator in microglia, was markedly suppressed in a dose-dependent manner following nobiletin treatment (1-50 µM) in LPS-stimulated BV-2 microglia cells. The inhibitory effect of nobiletin was similar to that of minocycline, a well-known microglial inactivator. Nobiletin significantly inhibited the release of the pro-inflammatory cytokine tumor necrosis factor (TNF-α) and interleukin-1ß (IL-1ß). LPS-induced phosphorylations of extracellular signal-regulated kinase (ERK), c-Jun NH(2)-terminal kinase (JNK), and p38 mitogen-activated protein kinases (MAPKs) were also significantly inhibited by nobiletin treatment. In addition, nobiletin markedly inhibited the LPS-induced pro-inflammatory transcription factor nuclear factor κB (NF-κB) signaling pathway by suppressing nuclear NF-κB translocation from the cytoplasm and subsequent expression of NF-κB in the nucleus. Taken together, these results may contribute to further exploration of the therapeutic potential and molecular mechanism of nobiletin in relation to neuroinflammation and neurodegenerative diseases.
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Antiinflamatorios/farmacología , Citrus/química , Inflamación/tratamiento farmacológico , Microglía/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Extractos Vegetales/farmacología , Animales , Transporte Biológico/efectos de los fármacos , Línea Celular , Núcleo Celular/efectos de los fármacos , Núcleo Celular/metabolismo , Citocinas/antagonistas & inhibidores , Citoplasma/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Frutas , Inflamación/metabolismo , Lipopolisacáridos , Ratones , Microglía/metabolismo , Minociclina/farmacología , Proteínas Quinasas Activadas por Mitógenos/antagonistas & inhibidores , FN-kappa B/antagonistas & inhibidores , Enfermedades Neurodegenerativas/tratamiento farmacológico , Óxido Nítrico/antagonistas & inhibidores , Fosforilación , Fitoterapia , Transducción de Señal/efectos de los fármacosRESUMEN
A nanoscale global ionic cluster [Co(H(2)O)(6) [symbol: see text] Co(8)L(12)](6+) packed in a face-centered cubic pattern was constructed as a "host", in which a magic number (H(2)O)(21) cluster was captured and stabilized in the tetrahedral hole as a "guest".
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Nanotecnología , Agua/química , Modelos Moleculares , Estructura Molecular , Difracción de Rayos XRESUMEN
The reaction of Δ/Λ-[Ru(bpy)2(py)2](2+) with a prochiral sulfide ligand, and then in situ oxidation, provide the corresponding Δ-[Ru(bpy)2{(R)-OSO-iPr}](+) and Λ-[Ru(bpy)2{(S)-OSO-iPr}](+) (OSO-iPr = 2-isopropylsulfonylbenzonate) enantiomers in a yield of 83% with 98% ee. The chiral sulfoxides were obtained by treatment of the sulfoxide complexes with TFA in a yield of 90% with 88-91% ee.
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Complejos de Coordinación/química , Rutenio/química , Sulfóxidos/química , Modelos Moleculares , Conformación Molecular , EstereoisomerismoRESUMEN
OBJECTIVES: Aromatherapy massage is commonly used for the stress management of healthy individuals, and also has been often employed as a therapeutic use for pain control and alleviating psychological distress, such as anxiety and depression, in oncological palliative care patients. However, the exact biological basis of aromatherapy massage is poorly understood. Therefore, we evaluated here the effects of aromatherapy massage interventions on multiple neurobiological indices such as quantitative psychological assessments, electroencephalogram (EEG) power spectrum pattern, salivary cortisol and plasma brain-derived neurotrophic factor (BDNF) levels. DESIGN: A control group without treatment (n = 12) and aromatherapy massage group (n = 13) were randomly recruited. They were all females whose children were diagnosed as attention deficit hyperactivity disorder and followed up in the Department of Psychiatry, Jeju National University Hospital. Participants were treated with aromatherapy massage for 40 min twice per week for 4 weeks (8 interventions). RESULTS: A 4-week-aromatherapy massage program significantly improved all psychological assessment scores in the Stat-Trait Anxiety Index, Beck Depression Inventory and Short Form of Psychosocial Well-being Index. Interestingly, plasma BDNF levels were significantly increased after a 4 week-aromatherapy massage program. Alpha-brain wave activities were significantly enhanced and delta wave activities were markedly reduced following the one-time aromatherapy massage treatment, as shown in the meditation and neurofeedback training. In addition, salivary cortisol levels were significantly reduced following the one-time aromatherapy massage treatment. CONCLUSIONS: These results suggest that aromatherapy massage could exert significant influences on multiple neurobiological indices such as EEG pattern, salivary cortisol and plasma BDNF levels as well as psychological assessments.
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Aromaterapia , Ondas Encefálicas/fisiología , Factor Neurotrófico Derivado del Encéfalo/sangre , Hidrocortisona/análisis , Masaje , Estrés Psicológico/terapia , Adulto , Electroencefalografía , Femenino , Humanos , Persona de Mediana Edad , Saliva/químicaRESUMEN
The hydrogen bonding and deprotonation processes between four ruthenium biimidazole complexes, namely [Ru(bpy)(2)(BiimH(2))](PF(6))(2) (1, bpy is bipyridine, BiimH(2) is 2,2'-biimidazole), [Ru(bpy)(2)-(BbimH(2))](PF(6))(2) (2, BbimH(2) is 2,2'-bibenzimidazole), and [Ru(bpy)(2)(DMBbimH(2))](PF(6))(2) (3, DMBbimH(2) is 7,7'-dimethyl-2,2'-bibenzimidazole) and [Ru(bpy)(2)(TMBbimH(2))](2+) (4, TMBbimH(2) is 5,6,5',6'-tetramethyl-2,2'-bibenzimidazole), and acetate are investigated. Their hydrogen bonded adducts are indeed trapped and observed by absorption spectra and electrochemical experiments in acetonitrile solution in the presence of an excess of acetic acid for the first time. The binding constants log K(B) for these adducts are 6.74 for 1·OAc, 7.11 for 2·OAc, 7.26 for 3·OAc, and 6.99 for 4·OAc. A new approach to calculate the deprotonation constant is also developed by establishing a set of circular equilibria. The equilibrium constants for the first deprotonation step of the complexes log K(A) are 2.74 for 1, 5.19 for 2, 4.54 for 3, and 3.78 for 4. The pK(a1) values of the complexes in acetonitrile solution are calculated by subtracting log K(A) from pK(a) (HOAc in acetonitrile), giving 19.6 for 1, 17.1 for 2, 17.8 for 3, and 18.5 for 4. The degree of proton transfer (D(PT)) can be quantified by the calculation of absorption spectral and redox data, which is 0.41 for 1·OAc, 0.53 for 2·OAc, 0.57 for 3·OAc, and 0.47 for 4·OAc. Interestingly, the binding constant log K(B) (7.26) and D(PT) value (0.57) both reach their maxima at a critical point, where pK(a1) for the complex is 17.8 and ΔpK(a) for the adduct is 4.5 (ΔpK(a) = pK(a)(HOAc) - pK(a1), in acetonitrile solution). Moreover, the binding constant log K(B) shows linear correlation with the degree of proton transfer D(PT).
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Acetatos/química , Imidazoles/química , Compuestos Organometálicos/química , Protones , Rutenio/química , Acetonitrilos/química , Electroquímica , Transporte de Electrón , Enlace de Hidrógeno , Soluciones , Agua/químicaRESUMEN
Excessive microglial activation-mediated neurotoxicity has been implicated in playing a crucial role in the pathogenesis of stroke and neurodegenerative diseases. Therefore, much attention has been paid to therapeutic strategies aimed at suppressing neurotoxic microglial activation. The microglial regulatory mechanism of methyl lucidone, a cyclopentenedione isolated from the stem bark of Lindera erythrocarpa Makino, was investigated in the present study. Methyl lucidone treatment (0.1-10 µM) significantly inhibited lipopolysaccharide (LPS, 100 ng/ml, 24 h)-stimulated nitric oxide (NO) production in a dose-dependent manner in both primary cortical microglia and BV-2 cell line. Moreover, it strongly inhibited LPS-stimulated secretion of pro-inflammatory cytokines, such as interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α). Methyl lucidone treatment markedly induced down-regulation of LPS-induced nuclear translocation of nuclear factor κB (NF-κB) through preventing the degradation of the inhibitory protein IκBα. In addition, phosphorylation of Akt and mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase (ERK) and p38 kinases were also suppressed by methyl lucidone. The cell viabilities of HT-22 neurons were significantly attenuated by treatment of the conditioned media containing neurotoxic secretary molecules from LPS-stimulated microglia. However, methyl lucidone significantly blocked neuronal cell death induced by microglial conditioned media. These neuroprotective effects of methyl lucidone were also confirmed in a neuron-microglia co-culture system using EGFP-transfected B35 neuroblastoma cell line. Taken together, these results suggest that methyl lucidone may have a neuroprotective potential via inhibition of neurotoxic microglial activation implicated in neurodegeneration.
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Ciclopentanos/farmacología , Microglía/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Animales , Muerte Celular/efectos de los fármacos , Corteza Cerebral/citología , Técnicas de Cocultivo , Medios de Cultivo Condicionados/metabolismo , Citocinas/metabolismo , Lindera/química , Lipopolisacáridos/farmacología , Microglía/citología , Microglía/metabolismo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , FN-kappa B/metabolismo , Neuronas/citología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Óxido Nítrico/biosíntesis , Fosforilación/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas , Transducción de Señal/efectos de los fármacosRESUMEN
Six possible isomers of mer-[M(II)(N,N,O-L)(2)] complex were observed in the solid state, in which spontaneous resolution of S,S-Lambda and R,R-Delta enantiomers of mer-[Co(N,N,O-L3)(2)] was achieved via pi-pi interactions.