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1.
Artigo em Inglês | MEDLINE | ID: mdl-31374962

RESUMO

In situ injection of Fe(II)-activated persulfate was carried out to oxidize chlorinated hydrocarbons and benzene, toluene, ethylbenzene, and xylene (BTEX) in groundwater in a contaminated site in North China Plain. To confirm the degradation of contaminants, an oxidant mixture of persulfate, ferrous sulfate, and citric acid was mixed with the main contaminants including 1,2,3-trichloropropane (TCP) and benzene before field demonstration. Then the mixed oxidant solution of 6 m3 was injected into an aquifer with two different depths of 8 and 15 m to oxidize a high concentration of TCP, other kinds of chlorinated hydrocarbons, and BTEX. In laboratory tests, the removal efficiency of TCP reached 61.4% in 24 h without other contaminants but the removal rate was decreased by the presence of benzene. Organic matter also reduced the TCP degradation rate and the removal efficiency was only 8.3% in 24 h. In the field test, as the solution was injected, the oxidation reaction occurred immediately, accompanied by a sharp increase of oxidation-reduction potential (ORP) and a decrease in pH. Though the concentration of pollutants increased due to the dissolution of non-aqueous phase liquid (NAPL) at the initial stage, BTEX could still be effectively degraded in subsequent time by persulfate in both aquifers, and their removal efficiency approached 100%. However, chlorinated hydrocarbon was relatively difficult to degrade, especially TCP, which had a relatively higher initial concentration, only had a removal efficiency of 30%-45% at different aquifers and monitoring wells. These finding are important for the development of injection technology for chlorinated hydrocarbon and BTEX contaminated site remediation.


Assuntos
Água Subterrânea/química , Hidrocarbonetos Clorados/química , Propano/análogos & derivados , Sulfatos/química , Poluentes Químicos da Água/química , China , Recuperação e Remediação Ambiental , Oxirredução , Propano/química
2.
Chemosphere ; 236: 124342, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31326752

RESUMO

The growth of algae in water and the taste and odour compounds produced by algal metabolism present a threat to water quality, public health and aquatic ecosystems and cannot be effectively removed by conventional water treatment processes. In this paper, a hydroxyl radical (OH)-based drinking water treatment system (DWTS) with a capacity of 480 m3 per day was built in the Xinglin water plant, Xiamen, China. With pretreatment at 0.88 mg L-1, sand filtration, and disinfection at 0.31 mg L-1 during the conveyance of algae-laden water within only 9.8 s, OH removed all five kinds of algae, with a total content of 35,180 cells mL-1, while ClO2 treatment left live and dead algae at 7150 cells mL-1, which would be transported into the pipe networks for the drinking water supply. Meanwhile, OH degraded 2-Methylisoborneol (2-MIB) from 175 to 4.4 ng L-1, which was below the Chinese standard of 10 ng L-1, while ClO2 degraded 2-MIB only to 155 ng L-1. Based on analyses of the mass spectra database, OH could mineralize 2-MIB by opening the ring structures of 2,2-dimethyl-1,3-cyclopentanedione and 2-methyl-cyclohexenecarboxaldehyde to produce small-molecule compounds. After OH pretreatment and OH disinfection, all water quality and disinfection by-product indexes met the Chinese Sanitary Standards for Drinking Water. Therefore, OH advanced oxidation produced using strong ionization discharge could be practically applied for the degradation of 2-MIB during the treatment of algae-laden water in the OH DWTS.


Assuntos
/química , Compostos Clorados/química , Cianobactérias/metabolismo , Radical Hidroxila/análise , Óxidos/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , China , Diaminas/química , Desinfecção/métodos , Água Potável/química , Ecossistema , Filtração/métodos , Odorantes/análise , Oxirredução , Propano/análogos & derivados , Propano/química , Paladar , Qualidade da Água , Abastecimento de Água
3.
Int J Pharm ; 566: 652-661, 2019 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-31181308

RESUMO

Pulmonary delivery is a highly attractive alternative to injections for biologics such as therapeutic proteins. However, bioavailabilities generally suffer from the presence of phagocytic cells that clear particulate matter entering the lung. In this study, microgel particles were developed using an all-aqueous two-phase system approach and evaluated for their efficacy as an inhalable controlled release system. Norbornene- and thiol-modified four- and eight-armed poly (ethylene glycol) with an average molecular mass of 10,000 Da were prepared as macromonomers for microgel formation. Emulsions of precursor solution droplets containing macromonomers and Irgacure 2959 as photocatalyst were prepared in a dextran solution. Irradiation with UV light was used to covalently crosslink the droplets by triggering the thiol-ene reaction. The resulting microgels were processed to dry powder inhaler formulations, and respirable aerodynamic sizes were assessed in vitro. Microgels were loaded with the model proteins lysozyme and bovine serum albumin, with encapsulation efficiencies of 51.5% and 73.6%, respectively. Depending on the macromonomer type, protein-loaded microgels released their cargo over a 6-14 day period. In an MTT assay, the particles did not show significant cytotoxicity, and their recognition by alveolar macrophages was considerably lower than for polystyrene control particles. This makes the microgels a promising pulmonary delivery system for proteins and other biologics.


Assuntos
Hidrogéis/administração & dosagem , Microesferas , Muramidase/administração & dosagem , Polietilenoglicóis/administração & dosagem , Soroalbumina Bovina/administração & dosagem , Administração por Inalação , Animais , Linhagem Celular , Preparações de Ação Retardada/administração & dosagem , Preparações de Ação Retardada/química , Hidrogéis/química , Pulmão/metabolismo , Macrófagos Alveolares/efeitos dos fármacos , Macrófagos Alveolares/metabolismo , Camundongos , Muramidase/química , Fagocitose , Polietilenoglicóis/química , Propano/administração & dosagem , Propano/análogos & derivados , Propano/química , Propano/efeitos da radiação , Soroalbumina Bovina/química , Raios Ultravioleta
4.
Org Lett ; 21(10): 3678-3681, 2019 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-31038317

RESUMO

Horisfieldones A (1) and B (2), two dimeric diarylpropanes featuring an unprecedentedly aromatic ring-contracted framework, were isolated from Horsfieldia kingii. Their structures and absolute configurations were determined by the inspection of extensive spectroscopic data and electronic circular dichroism calculations. Molecular modeling analysis, in vitro enzyme-based bioassays, and structure-activity relationship analysis of these isolates revealed that (+)-1 (IC50 = 35.1 ± 3.9 µM, SI > 11.4) could present a new class of human DOPA decarboxylase inhibitor.


Assuntos
Dopa Descarboxilase/farmacologia , Propano/farmacologia , Dicroísmo Circular , Dopa Descarboxilase/química , Humanos , Concentração Inibidora 50 , Modelos Moleculares , Estrutura Molecular , Propano/análogos & derivados , Propano/química , Relação Estrutura-Atividade
5.
Nat Chem ; 11(6): 578-586, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30988414

RESUMO

Polymerization reactions conducted inside cells must be compatible with the complex intracellular environment, which contains numerous molecules and functional groups that could potentially prevent or quench polymerization reactions. Here we report a strategy for directly synthesizing unnatural polymers in cells through free radical photopolymerization using a number of biocompatible acrylic and methacrylic monomers. This offers a platform to manipulate, track and control cellular behaviour by the in cellulo generation of macromolecules that have the ability to alter cellular motility, label cells by the generation of fluorescent polymers for long-term tracking studies, as well as generate a variety of nanostructures within cells. It is remarkable that free radical polymerization chemistry can take place within such complex cellular environments. This demonstration opens up a multitude of new possibilities for how chemists can modulate cellular function and behaviour and for understanding cellular behaviour in response to the generation of free radicals.


Assuntos
Radicais Livres/química , Polimerização/efeitos da radiação , Ácidos Polimetacrílicos/síntese química , Poliestirenos/síntese química , Acrilatos/química , Acrilatos/efeitos da radiação , Acrilatos/toxicidade , Citoesqueleto de Actina/efeitos dos fármacos , Compostos de Anilina/química , Compostos de Anilina/efeitos da radiação , Compostos de Anilina/toxicidade , Movimento Celular/efeitos dos fármacos , Fluorescência , Células HeLa , Humanos , Metacrilatos/química , Metacrilatos/efeitos da radiação , Metacrilatos/toxicidade , Propano/análogos & derivados , Propano/química , Propano/efeitos da radiação , Fase S/efeitos dos fármacos , Estirenos/química , Estirenos/efeitos da radiação , Estirenos/toxicidade , Raios Ultravioleta , Compostos de Vinila/química , Compostos de Vinila/efeitos da radiação , Compostos de Vinila/toxicidade
6.
J Ind Microbiol Biotechnol ; 46(5): 675-685, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30706246

RESUMO

Propane is the main component of liquefied petroleum gas and is derived from crude oil processing. Methanotrophic bacteria can convert various alkanes using methane monooxygenase enzyme to primary alcohols. These are further oxidized to various aldehydes by alcohol dehydrogenases or methanol dehydrogenases. In this study, 2-propanol was produced from propane using the whole cells of Methylosinus trichosporium OB3b, Methylomicrobium alcaliphilum 20Z, and Methylomonas sp. DH-1 as the biocatalysts. The biocatalytic process of converting propane to 2-propanol was optimized by the use of several inhibitors and additives, such as EDTA, sodium phosphate, and sodium formate to prevent oxidation of 2-propanol to acetone and to enhance conversion of propane to propanol. The maximum titer of 2-propanol was 0.424 g/L, 0.311 g/L, and 0.610 g/L for Methylomonas sp. DH-1, M. alcaliphilum 20Z, and M. trichosporium OB3b whole cells, respectively. These results showed that type I and type II methanotrophs could be used as the potent biocatalyst for conversion of propane to propanol.


Assuntos
2-Propanol/química , Methylomonas/metabolismo , Methylosinus trichosporium/metabolismo , Propano/química , Acetona , Oxirredutases do Álcool/química , Álcoois , Alcanos , Catálise , Formiatos/química , Microbiologia Industrial , Methylococcaceae , Oxirredução , Oxigenases/química , Especificidade da Espécie
7.
J Sci Food Agric ; 99(8): 3776-3784, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30637745

RESUMO

BACKGROUND: Many conventional extraction methods for basils (Ocimum sp. Lamiaceae) produce only the extract as a usable product and leave the extracted herb as a waste product. We demonstrate partial extraction of chemically and morphologically diverse basil cultivars using propane at low temperature (20-27 °C) and pressure (950-1200 kPa) and evaluate the process for production of dual products, the extracted herb (raffinate) and the herb extract in terms of aromatic content and color. RESULTS: The extracts contained aromatic compounds that were characteristic of but not always identical in terms of relative abundance to the dehydrated herb. Extraction decreased total aromatics in the raffinate by 12-43% but the individual aromatic proportions remained essentially the same, preserving flavor characteristics of the raffinate. Color was mostly unchanged by the extraction process. CONCLUSION: Partial propane extraction resulted in two useful basil products (an extract and extraction raffinate). Aromatic extractability was tissue and cultivar dependent for basils. Therefore, partial extraction protocols should be optimized according to cultivar/plant tissue abundance to provide consistent aromatic intensity of these potential food products. © 2019 Society of Chemical Industry.


Assuntos
Fracionamento Químico/métodos , Ocimum basilicum/química , Extratos Vegetais/isolamento & purificação , Compostos Orgânicos Voláteis/isolamento & purificação , Fracionamento Químico/instrumentação , Manipulação de Alimentos , Extratos Vegetais/química , Propano/química , Temperatura , Compostos Orgânicos Voláteis/química
8.
Int J Biol Macromol ; 126: 1030-1036, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30611805

RESUMO

It is highly desirable to develop biodegradable UV-shielding materials from the renewable resources as the ever-increasing demand for the sustainable environment. In this work, TiO2 decorated lignin particles (TiO2@lignin) were synthesized successfully by hydrothermal method in aqueous solution to improve the UV shielding performance of lignin particles. The poly(propylene carbonate) (PPC) composite films (thickness of ~23 µm) with different contents of TiO2@lignin were prepared via a blade-casting method. Morphological analysis showed that the TiO2@lignin dispersed uniformly in the PPC matrix with a good miscibility. UV-vis transmission spectra results revealed that the PPC composite film containing 5 wt% TiO2@lignin could absorb about 90% of UV light in the full UV band (200-400 nm), indicating the TiO2@lignin had a good UV-shielding property. Moreover, the presence of TiO2@lignin could significantly improve the thermal stability of the PPC/TiO2@lignin composite films. The DMA results showed that the introduction of TiO2@lignin could enhance the storage modulus and glass transition temperature simultaneously.


Assuntos
Materiais Biocompatíveis/química , Química Verde , Lignina/química , Propano/análogos & derivados , Titânio/química , Raios Ultravioleta , Varredura Diferencial de Calorimetria , Módulo de Elasticidade , Nanopartículas/química , Nanopartículas/ultraestrutura , Espectroscopia Fotoeletrônica , Propano/química , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termogravimetria , Difração de Raios X
9.
Anticancer Agents Med Chem ; 19(3): 347-355, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30479221

RESUMO

BACKGROUND: Cancer can be considered as a disease in which normal cells start behaving badly, multiplying uncontrollably, ignoring signals to stop and accumulating to form a mass that is generally termed as a tumor. Apoptosis or programmed cell death is a physiological process that enables organisms to control their cell numbers in many developmental and physiological settings and to eliminate unwanted cells and it plays essential role in chemotherapy-induced tumor-cell killing. The correct balance between apoptosis and inhibition of apoptosis is important in animal development as well as in tissue homeostasis. The aim of this paper is to introduce the readers about the design strategy and synthesis of effective cytotoxic and apoptotic inducing agents based on benzo[d]imidazo[2,1-b]thiazole scaffold. METHODS: Benzo[d]imidazo[2,1-b]thiazole-propenone conjugates were synthesized by the condensation of 7- methoxy-2-(aryl)benzo[d]imidazo[2,1-b]thiazol-3-yl)prop-2-yn-1-ones with aryl/hetero aryl amines in ethanol at room temperature. These in turn were obtained from 7-methoxy-2-(aryl)benzo[d]imidazo[2,1-b]thiazole-3- carbaldehydes on treatment with ethynylmagnesium bromide followed by oxidation. RESULTS: 3-Arylaminopropenone linked 2-arylbenzo[d]imidazo[2,1-b]thiazole conjugates prepared in this investigation exhibited significant cytotoxic activity and arrested HeLa cancer cells in G1 phase. The treatment of the conjugate led to 40% of loss of mitochondrial membrane potential (DΨm) in HeLa cells and 4 fold increase in the levels of reactive oxygen species (ROS). In addition, it induces apoptosis in HeLa cells, this was examined by the wound healing assay, Actin filaments and Hoechst staining assay. CONCLUSION: The encouraging biological profile exhibited by these 3-arylaminopropenone 2-aryl linked benzo[d]imidazo[2,1-b]thiazole conjugates demonstrate that they have the potential to be developed as a lead by further structural modifications to obtain potential chemotherapeutic agents that are likely to target the HeLa cancer cells.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Imidazóis/farmacologia , Propano/farmacologia , Tiazóis/farmacologia , Antineoplásicos/química , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Imidazóis/química , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Estrutura Molecular , Propano/análogos & derivados , Propano/química , Espécies Reativas de Oxigênio/análise , Espécies Reativas de Oxigênio/metabolismo , Relação Estrutura-Atividade , Tiazóis/química , Cicatrização/efeitos dos fármacos
10.
Molecules ; 23(10)2018 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-30347858

RESUMO

Traditional ionic liquids (ILs) catalysts suffer from the difficulty of product purification and can only be used in homogeneous catalytic systems. In this work, by reacting ILs with co-catalyst (ZnBr2), we successfully converted three polyether imidazole ionic liquids (PIILs), i.e., HO-[Poly-epichlorohydrin-methimidazole]Cl (HO-[PECH-MIM]Cl), HOOC-[Poly-epichlorohydrin-methimidazole]Cl (HOOC-[PECH-MIM]Cl), and H2N-[Poly-epichlorohydrin-methimidazole]Cl (H2N-[PECH-MIM]Cl), to three composite PIIL materials, which were further immobilized on ZSM-5 zeolite by chemical bonding to result in three immobilized catalysts, namely ZSM-5-HO-[PECH-MIM]Cl/[ZnBr2], ZSM-5-HOOC-[PECH-MIM]Cl/[ZnBr2], and ZSM-5-H2N-[PECH-MIM]Cl/[ZnBr2]. Their structures, thermal stabilities, and morphologies were fully characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The amount of composite PIIL immobilized on ZSM-5 was determined by elemental analysis. Catalytic performance of the immobilized catalysts was evaluated through the catalytic synthesis of propylene carbonate (PC) from CO2 and propylene oxide (PO). Influences of reaction temperature, time, and pressure on catalytic performance were investigated through the orthogonal test, and the effect of catalyst circulation was also studied. Under an optimal reaction condition (130 °C, 2.5 MPa, 0.75 h), the composite catalyst, ZSM-5-HOOC- [PECH-MIM]Cl/[ZnBr2], exhibited the best catalytic activity with a conversion rate of 98.3% and selectivity of 97.4%. Significantly, the immobilized catalyst could still maintain high heterogeneous catalytic activity even after being reused for eight cycles.


Assuntos
Imidazóis/química , Líquidos Iônicos/química , Propano/análogos & derivados , Zeolitas/química , Alcenos/química , Apatitas/química , Dióxido de Carbono/química , Catálise , Imidazóis/síntese química , Líquidos Iônicos/síntese química , Microscopia Eletrônica de Varredura , Propano/síntese química , Propano/química , Difração de Raios X
11.
Biomed Res Int ; 2018: 7861207, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30310819

RESUMO

Background: The aim of this study was to compare the in vitro antibacterial activity of two compounds derived from Alliaceae, PTS (propyl-propane-thiosulfinate), and PTSO (propyl-propane-thiosulfonate), with that of other antibiotics commonly used against bacteria isolated from humans. Materials and Methods: A total of 212 gram-negative bacilli and 267 gram-positive cocci isolated from human clinical samples and resistant to at least one group of antibiotics were selected. In order to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) to various antibiotics as well as PTS and PTSO, all isolates underwent broth microdilution assay. Results: PTS showed moderate activity against Enterobacteriaceae with MIC50 (and MBC50) and MIC90 (and MBC90) values of 256-512 mg/L, while PTSO showed greater activity with MIC50 and MIC90 values of 64-128 mg/L and MBC50 and MBC90 values of 128-512 mg/L. These data show the bactericidal activity of both compounds and indicate that PTSO was more active than PTS against this group of bacteria. Both compounds showed lower activity against P. aeruginosa (MIC50 = 1024 mg/L, MIC90 = 2048 mg/L, MBC50 = 2048 mg/L, and MBC90 = 2048 mg/L, for PTS; MIC50 = 512 mg/L, MIC90 = 1024 mg/L, MBC50 = 512 mg/L, and MBC90 = 2048 mg/L, for PTSO) compared to those obtained in others nonfermenting gram-negative bacilli (MIC50 = 128 mg/L, MIC90 = 512 mg/L, MBC50 = 128 mg/L, and MBC90 = 512 mg/L, for PTS; MIC50 = 64 mg/L, MIC90 = 256 mg/L, MBC50 = 64 mg/L, and MBC90 = 256 mg/L, for PTSO) and also indicate the bactericidal activity of both compounds against these groups of bacteria. Finally, the activity against S. aureus, E. faecalis, and S. agalactiae was higher than that observed against enterobacteria, especially in the case of PTSO (MIC50 = 8 mg/L, MIC90 = 8 mg/L, MBC50 = 32 mg/L, and MBC90 = 64 mg/L, in S. aureus; MIC50 = 4 mg/L, MIC90 = 8 mg/L, MBC50 = 8 mg/L, and MBC90 = 16 mg/L, in E. faecalis and S. agalactiae). Conclusion: PTS and PTSO have a significant broad spectrum antibacterial activity against multiresistant bacteria isolated from human clinical samples. Preliminary results in present work provide basic and useful information for development and potential use of these compounds in the treatment of human infections.


Assuntos
Allium/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla , Ácidos Tiossulfônicos/farmacologia , Bactérias/isolamento & purificação , Infecções Bacterianas/microbiologia , Humanos , Testes de Sensibilidade Microbiana , Extratos Vegetais/química , Propano/química
12.
Molecules ; 23(9)2018 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-30201888

RESUMO

We aimed to develop new effective catalysts for the synthesis of propylene carbonate from propylene oxide and carbon dioxide. A kind of Mx+LClx coordination complex was fabricated based on the chelating tridentate ligand 2,6-bis[1-(phenylimino)ethyl] pyridine (L). The obtained products were characterized by elemental analysis, infrared spectroscopy, ultraviolet spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. It was found that the catalytic activity of the complexes with different metal ions, the same ligand differed and co-catalyst, where the order of greatest to least catalytic activity was 2 > 3 > 1. The catalytic system composed of complex 2 and DMAP proved to have the better catalytic performance. The yields for complex 2 systems was 86.7% under the reaction conditions of 100 °C, 2.5 MPa, and 4 h. The TOF was 1026 h-¹ under the reaction conditions of 200 °C, 2.5 MPa, and 1 h. We also explored the influence of time, pressure, temperature, and reaction substrate concentration on the catalytic reactions. A hypothetical catalytic reaction mechanism is proposed based on density functional theory (DFT) calculations and the catalytic reaction results.


Assuntos
Dióxido de Carbono/química , Complexos de Coordenação/química , Compostos de Epóxi/química , Propano/análogos & derivados , Piridinas/química , Catálise , Cristalografia por Raios X , Reação de Cicloadição , Ligantes , Conformação Molecular , Propano/síntese química , Propano/química , Eletricidade Estática
13.
Eur J Med Chem ; 158: 534-547, 2018 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-30243155

RESUMO

[M(sac)2(dppp)] (1 and 2), [M(dppp)2](sac)2 (3 and 4) and [M(sac)2(dppb)] (5 and 6) complexes, where M = PdII (1, 3 and 5) and PtII (2, 4 and 6), sac = saccharinate, dppp = 1,3-bis(diphenylphosphino)propane and dppb = 1,4-bis(diphenylphosphino)butane, were synthesized and characterized by IR, NMR, ESI-MS and X-ray diffraction. The anticancer activity of the complexes against human lung (A549), breast (MCF-7), prostate (DU145) and colon (HCT116) cancer cell lines showed that the cationic complexes of dppp (3 and 4) and neutral Pt complex of dppb (6) were the most active agents of series. 3 and 4 exhibited antiproliferative activity, while 6 was highly cytotoxic compared to cisplatin. These complexes were therefore subjected to further investigations to ascertain the possible role of lipophilicity, cellular uptake and DNA/HSA binding in their biological activity. Flow cytometry analysis revealed that complex 6 induced apoptotic cell death in A549 and HCT116 cells and caused the cell cycle arrest at the S phase and overproduction of reactive oxygen species (ROS), giving rise to mitochondrial depolarization and DNA damage.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Compostos Organoplatínicos/química , Compostos Organoplatínicos/farmacologia , Paládio/química , Paládio/farmacologia , Células A549 , Antineoplásicos/síntese química , Butanos/síntese química , Butanos/química , Butanos/farmacologia , Linhagem Celular Tumoral , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Células HCT116 , Humanos , Neoplasias/tratamento farmacológico , Compostos Organoplatínicos/síntese química , Fosfinas/síntese química , Fosfinas/química , Fosfinas/farmacologia , Propano/síntese química , Propano/química , Propano/farmacologia
14.
Inorg Chem ; 57(18): 11738-11745, 2018 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-30156099

RESUMO

Engineered P450s can catalyze some non-natural reactions with high efficiency and excellent selectivity, such as the carbine transfer, nitrene transfer, C-H insertion, and C-H amination, opening alternative routes for sustainable production of chemicals. Recent experiments revealed that two engineered cytochrome P450 enzymes (P450BM3-CIS and P411BM3-CIS) show different efficiencies and stereoselectivities in the olefin cyclopropanation, but key factors that affect the activity remain unclear. In this work, both quantum mechanics (QM) and QM/molecular mechanics (MM) methods were employed to explore the catalytic reactions and selectivity of these two engineered cytochrome P450 enzymes. On the basis of our results, the cyclopropanation of styrene is suggested to mainly occur on the open-shell singlet (OSS) and triplet state surfaces, which contain two elementary steps. The reactive iron(III)-porphyrin carbene (IPC) radical first attacks the terminal alkenyl group of styrene to form a C-radical intermediate, which then undergoes a cyclization reaction affording the cyclopropanation products. Importantly, it is found that the stereoselectivity of cyclopropanations is elucidated only if considering the real protein environment, and the stereoselectivity is determined by multiple factors, such as the relative orientation of IPC to styrene, the binding affinity of the substrate, and the reaction barriers of rate-limiting steps. It is the enzymatic environment that makes the reaction highly stereoselective, which provides useful clues for designing whole-cell catalysts for non-natural chemical reactions.


Assuntos
Alcenos/química , Sistema Enzimático do Citocromo P-450/metabolismo , Propano/química , Teoria Quântica , Alcenos/metabolismo , Catálise , Domínio Catalítico , Ciclização , Ferro/química , Modelos Moleculares , Porfirinas/química , Estereoisomerismo
15.
Int J Mol Sci ; 19(7)2018 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-30011782

RESUMO

The blends of Poly(propylene carbonate) (PPC) and polyester-based thermoplastic polyurethane (TPU) were melt compounded in an internal mixer. The compatibility, thermal behaviors, mechanical properties and toughening mechanism of the blends were investigated using Fourier transform infrared spectra (FTIR), tensile tests, impact tests, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and dynamic mechanical analysis technologies. FTIR and SEM examination reveal strong interfacial adhesion between PPC matrix and suspended TPU particles. Dynamic mechanical analyzer (DMA) characterize the glass transition temperature, secondary motion and low temperature properties. By the incorporation of TPU, the thermal stabilities are greatly enhanced and the mechanical properties are obviously improved for the PPC/TPU blends. Moreover, PPC/TPU blends exhibit a brittle-ductile transition with the addition of 20 wt % TPU. It is considered that the enhanced toughness results in the shear yielding occurred in both PPC matrix and TPU particles of the blends.


Assuntos
Plásticos Biodegradáveis/química , Polímeros/química , Poliuretanos/química , Propano/análogos & derivados , Varredura Diferencial de Calorimetria , Ligação de Hidrogênio , Microscopia Eletrônica de Varredura , Propano/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Resistência à Tração
16.
J Am Chem Soc ; 140(27): 8487-8496, 2018 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-29894625

RESUMO

We present a series of QM/MM calculations aimed at understanding the mechanism of the biological dehydration of glycerol. Strikingly and unusually, this process is catalyzed by two different radical enzymes, one of which is a coenzyme-B12-dependent enzyme and the other which is a coenzyme-B12-independent enzyme. We show that glycerol dehydration in the presence of the coenzyme-B12-dependent enzyme proceeds via a 1,2-OH shift, which benefits from a significant catalytic reduction in the barrier. In contrast, the same reaction in the presence of the coenzyme-B12-independent enzyme is unlikely to involve the 1,2-OH shift; instead, a strong preference for direct loss of water from a radical intermediate is indicated. We show that this preference, and ultimately the evolution of such enzymes, is strongly linked with the reactivities of the species responsible for abstracting a hydrogen atom from the substrate. It appears that the hydrogen-reabstraction step involving the product-related radical is fundamental to the mechanistic preference. The unconventional 1,2-OH shift seems to be required to generate a product-related radical of sufficient reactivity to cleave the relatively inactive C-H bond arising from the B12 cofactor. In the absence of B12, it is the relatively weak S-H bond of a cysteine residue that must be homolyzed. Such a transformation is much less demanding, and its inclusion apparently enables a simpler overall dehydration mechanism.


Assuntos
Clostridium butyricum/enzimologia , Gliceraldeído/análogos & derivados , Glicerol/metabolismo , Hidroliases/metabolismo , Klebsiella pneumoniae/enzimologia , Propano/metabolismo , Vitamina B 12/metabolismo , Biocatálise , Clostridium butyricum/química , Clostridium butyricum/metabolismo , Gliceraldeído/química , Gliceraldeído/metabolismo , Glicerol/química , Klebsiella pneumoniae/química , Klebsiella pneumoniae/metabolismo , Modelos Moleculares , Propano/química , Vitamina B 12/química
18.
Int J Pharm ; 544(1): 213-221, 2018 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-29630934

RESUMO

The use of various harmful organic solvents for microparticle formulations is still widespread. Here, an alternative low toxicity solvent (propylene carbonate; PC) is proposed for the preparation of poly(lactic-co-glycolic-acid) (PLGA) microparticles. Based on the classical emulsification-solvent extraction methodology, the use of PC offers the unique advantage of an additional solvent extraction step using hydrolytic solvent cleavage during microparticle preparation. Spherical, rough-surfaced microparticles were obtained with a volume median diameter range from 20 to 60 µm. The residual PC content has been identified to be the major factor for the solidification hindrance, leading to polymeric Tg shifting due to a plasticizing effect. When applying the enhanced PC extraction step, the residual PC content was lowered from 8.8% to 2.7% and subsequently Tg values shifted from 8.2 to 37.7 °C. Additionally, the hydrolytic solvent cleavage confirmed to have no impact on the PLGA stability. This method presents a significant advancement towards replacing of conventional solvents in the microparticle preparation due to more efficient solvent extraction.


Assuntos
Ácido Láctico/química , Ácido Poliglicólico/química , Polissorbatos/química , Propano/análogos & derivados , Solventes/química , Composição de Medicamentos , Emulsões , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Propano/química
19.
J Biol Inorg Chem ; 23(3): 481-491, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29627860

RESUMO

[FeFe] Hydrogenases catalyze the reversible conversion of H2 into electrons and protons. Their catalytic site, the H-cluster, contains a generic [4Fe-4S]H cluster coupled to a [2Fe]H subsite [Fe2(ADT)(CO)3(CN)2]2-, ADT = µ(SCH2)2NH. Heterologously expressed [FeFe] hydrogenases (apo-hydrogenase) lack the [2Fe]H unit, but this can be incorporated through artificial maturation with a synthetic precursor [Fe2(ADT)(CO)4(CN)2]2-. Maturation with a [2Fe] complex in which the essential ADT amine moiety has been replaced by CH2 (PDT = propane-dithiolate) results in a low activity enzyme with structural and spectroscopic properties similar to those of the native enzyme, but with simplified redox behavior. Here, we study the effect of sulfur-to-selenium (S-to-Se) substitution in the bridging PDT ligand incorporated in the [FeFe] hydrogenase HydA1 from Chlamydomonas reinhardtii using magnetic resonance (EPR, NMR), FTIR and spectroelectrochemistry. The resulting HydA1-PDSe enzyme shows the same redox behavior as the parent HydA1-PDT. In addition, a state is observed in which extraneous CO is bound to the open coordination site of the [2Fe]H unit. This state was previously observed only in the native enzyme HydA1-ADT and not in HydA1-PDT. The spectroscopic features and redox behavior of HydA1-PDSe, resulting from maturation with [Fe2(PDSe)(CO)4(CN)2]2-, are discussed in terms of spin and charge density shifts and provide interesting insight into the electronic structure of the H-cluster. We also studied the effect of S-to-Se substitution in the [4Fe-4S] subcluster. The reduced form of HydA1 containing only the [4Fe-4Se]H cluster shows a characteristic S = 7/2 spin state which converts back into the S = 1/2 spin state upon maturation with a [2Fe]-PDT/ADT complex.


Assuntos
Hidrogenase/química , Ferro/química , Propano/química , Compostos de Selênio/química , Compostos de Sulfidrila/química , Ligantes , Análise Espectral/métodos
20.
Bioorg Chem ; 77: 619-624, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29501029

RESUMO

One new 1,3-diphenylpropane (1) together with six known analogues (2-7) were firstly isolated from the stem and root bark of Daphne giraldii. Their structures were determined by comprehensive NMR and HRESIMS spectroscopic data analyses. All the isolates were evaluated for their cytotoxicity against two hepatocellular carcinoma cell lines (HepG2 and Hep3B). Among them, compound 5 showed the most significant cytotoxicity against Hep3B cells, with an IC50 value of 17.21 µM. A further study demonstrated that 5 obviously induced apoptotic cell death as well as the inactivation of nuclear factor kappa B p65 (NF-κB p65) in Hep3B cells. In addition, BAY 11-7082 (BAY), a NF-кB inhibitor, was used to determine the role of NF-кB signaling in 5-treated Hep3B cells. The results suggested that BAY could enhance 5-induced apoptosis of Hep3B cells. In conclusion, the data provided that 5 might be a potential candidate for the treatment of hepatocellular carcinoma through NF-κB inhibition.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Carcinoma Hepatocelular/tratamento farmacológico , Daphne/química , Neoplasias Hepáticas/tratamento farmacológico , NF-kappa B/antagonistas & inibidores , Propano/análogos & derivados , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células Hep G2 , Humanos , Neoplasias Hepáticas/patologia , Estrutura Molecular , NF-kappa B/metabolismo , Propano/química , Propano/isolamento & purificação , Propano/farmacologia , Relação Estrutura-Atividade
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