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https://www.readbyqxmd.com/read/28701955/therapeutic-properties-of-bioactive-compounds-from-different-honeybee-products
#1
REVIEW
Laura Cornara, Marco Biagi, Jianbo Xiao, Bruno Burlando
Honeybees produce honey, royal jelly, propolis, bee venom, bee pollen, and beeswax, which potentially benefit to humans due to the bioactives in them. Clinical standardization of these products is hindered by chemical variability depending on honeybee and botanical sources, but different molecules have been isolated and pharmacologically characterized. Major honey bioactives include phenolics, methylglyoxal, royal jelly proteins (MRJPs), and oligosaccharides. In royal jelly there are antimicrobial jelleins and royalisin peptides, MRJPs, and hydroxy-decenoic acid derivatives, notably 10-hydroxy-2-decenoic acid (10-HDA), with antimicrobial, anti-inflammatory, immunomodulatory, neuromodulatory, metabolic syndrome preventing, and anti-aging activities...
2017: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/28696043/the-bioelectric-well-a-novel-approach-for-in%C3%A2-situ-treatment-of-hydrocarbon-contaminated-groundwater
#2
Enza Palma, Matteo Daghio, Andrea Franzetti, Marco Petrangeli Papini, Federico Aulenta
Groundwater contamination by petroleum hydrocarbons (PHs) is a widespread problem which poses serious environmental and health concerns. Recently, microbial electrochemical technologies (MET) have attracted considerable attention for remediation applications, having the potential to overcome some of the limiting factors of conventional in situ bioremediation systems. So far, field-scale application of MET has been largely hindered by the limited availability of scalable system configurations. Here, we describe the 'bioelectric well' a bioelectrochemical reactor configuration, which can be installed directly within groundwater wells and can be applied for in situ treatment of organic contaminants, such as PHs...
July 11, 2017: Microbial Biotechnology
https://www.readbyqxmd.com/read/28694551/aryne-cycloaddition-reactions-of-benzodioxasilines-as-aryne-precursors-generated-by-catalytic-reductive-ortho-c-h-silylation-of-phenols-with-traceless-acetal-directing-groups
#3
Parham Asgari, Udaya Sree Dakarapu, Hiep H Nguyen, Junha Jeon
Diversely substituted arylsilyl triflates, as aryne precursors for aryne cycloaddition reactions, were accessed from benzodioxasilines. Catalytic reductive C-H ortho-silylation of phenols with traceless acetal directing groups was exploited to prepare benzodioxasilines. Sequential addition of MeLi and then trifluoromethanesulfonic anhydride to benzodioxasilines provided arylsilyl triflates in a single pot. Notably, this approach was successfully utilized to prepare sterically hindered 1,2,3-trisubstituted arylsilyl triflates, which ultimately underwent fluoride-mediated aryne cycloaddition...
July 20, 2017: Tetrahedron
https://www.readbyqxmd.com/read/28692115/an-optimized-protocol-for-dna-extraction-in-plants-with-a-high-content-of-secondary-metabolites-based-on-leaves-of-mimosa-tenuiflora-willd-poir-leguminosae
#4
S R Arruda, D G Pereira, M M Silva-Castro, M G Brito, A M Waldschmidt
Some species are characterized by a high content of tannins, alkaloids, and phenols in their leaves. These secondary metabolites are released during DNA extraction and might hinder molecular studies based on PCR (polymerase chain reaction). To provide an efficient method to extract DNA, Mimosa tenuiflora, an important leguminous plant from Brazilian semiarid region used in popular medicine and as a source of fuelwood or forage, was used. Eight procedures previously reported for plants were tested and adapted from leaf tissues of M...
July 6, 2017: Genetics and Molecular Research: GMR
https://www.readbyqxmd.com/read/28665029/impact-of-macroporosity-on-catalytic-upgrading-of-fast-pyrolysis-bio-oil-by-esterification-over-silica-sulfonic-acids
#5
Jinesh Manayil, Amin Osatiashtiani, Alvaro Mendoza, Christopher Parlett, Lee Durndell, Mark Isaacs, Chrysoula Michailof, Eleni Heracleous, Angelos Lappas, Adam Lee, Karen Wilson
Fast pyrolysis bio-oils possess unfavourable physicochemical properties and poor stability, due in large part to the presence of carboxylic acids, which hinders their use as biofuels. Catalytic esterification offers an atom and energy efficient route to upgrade pyrolysis bio-oils. Propyl sulfonic acid silicas are active for carboxylic acid esterification but suffer mass-transport limitations for bulky substrates. Macropore (200 nm) incorporation enhances the activity of mesoporous SBA-15 architectures (post-functionalised by hydrothermal saline promoted grafting) for the esterification of linear carboxylic acids, with the magnitude of turnover frequency (TOF) enhancement increasing with chain length from 5 % (C3) to 110 % (C12)...
June 30, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28650143/coupled-carbonization-strategy-toward-advanced-hard-carbon-for-high-energy-sodium-ion-battery
#6
Huimin Zhang, Hai Ming, Wenfeng Zhang, Gaoping Cao, Yusheng Yang
Sodium-ion batteries (SIBs) are expected to be a promising commercial alternative to lithium-ion batteries for grid electricity storage due to their potential low cost in the near future. Up to the present, the anode material still remains a great challenge for the application of SIBs, especially at room temperature. Graphite has an obvious limitation to store larger radius sodium ions (Na(+)) in comparison with lithium ions (Li(+)), while the hard carbon with large interlayer distance can demonstrate a relatively high storage capability and durable cycle life...
July 19, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28628319/mechanism-of-phenol-alkylation-in-zeolite-h-bea-using-in-situ-solid-state-nmr-spectroscopy
#7
Zhenchao Zhao, Hui Shi, Chuan Wan, Mary Y Hu, Yuanshuai Liu, Donghai Mei, Donald M Camaioni, Jian Zhi Hu, Johannes A Lercher
The reaction mechanism of solid-acid-catalyzed phenol alkylation with cyclohexanol and cyclohexene in the apolar solvent decalin has been studied using in situ (13)C MAS NMR spectroscopy. Phenol alkylation with cyclohexanol sets in only after a majority of cyclohexanol is dehydrated to cyclohexene. As phenol and cyclohexanol show similar adsorption strength, this strict reaction sequence is not caused by the limited access of phenol to cyclohexanol, but is due to the absence of a reactive electrophile as long as a significant fraction of cyclohexanol is present...
June 27, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28612283/cell-laden-microgel-prepared-using-a-biocompatible-aqueous-two-phase-strategy
#8
Yang Liu, Natalia Oshima Nambu, Masahito Taya
Microfluidic methods are frequently used to produce cell-laden microgels for various biomedical purposes. Such microfluidic methods generally employ oil-water systems. The poor distribution of crosslinking reagents in the oil phase limits the available gelation strategies. Extracting the microgel from the oil-phase also reduces its production efficiency. In this study, an aqueous two-phase system (ATPS) involving dextran (DEX) and polyethylene glycol (PEG) was used to prepare cell-laden microgel. This avoided the problems associated with an oil phase...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28602294/probing-the-specificity-of-polyurethane-foam-as-a-solid-phase-extractant-extractability-governing-molecular-attributes-of-lipophilic-phenolic-compounds
#9
Jie Han, Zhi Cao, Wei Qiu, Wei Gao, Jiangyong Hu, Baoshan Xing
The long-proposed use of open-cell polyurethane foam (PUF) as a convenient 'solid-phase extractant' for aqueous organic compounds has been hindered by a critical lack of understanding on the underlying specificity of its extraction mechanism. In this work, we tasked ourselves to understand the hierarchy of molecular structure, properties, and partitioning characteristics of compounds in PUF and aqueous phase by targeting lipophilic phenolic compounds (LPCs) as a group of primary targets for PUF extraction. Using six structurally related bisphenol analogs as comparative probes, we identified molecular lipophilicity and H-bond acidity as key molecular attributes that governed their extractability by PUF...
September 1, 2017: Talanta
https://www.readbyqxmd.com/read/28567247/polysulfide-1-oxides-react-with-peroxyl-radicals-as-quickly-as-hindered-phenolic-antioxidants-and-do-so-by-a-surprising-concerted-homolytic-substitution
#10
Jean-Philippe R Chauvin, Evan A Haidasz, Markus Griesser, Derek A Pratt
Polysulfides are important additives to a wide variety of industrial and consumer products and figure prominently in the chemistry and biology of garlic and related medicinal plants. Although their antioxidant activity in biological contexts has received only recent attention, they have long been ascribed 'secondary antioxidant' activity in the chemical industry, where they are believed to react with the hydroperoxide products of autoxidation to slow the auto-initiation of new autoxidative chain reactions. Herein we demonstrate that the initial products of trisulfide oxidation, trisulfide-1-oxides, are surprisingly reactive 'primary antioxidants', which slow autoxidation by trapping chain-carrying peroxyl radicals...
October 1, 2016: Chemical Science
https://www.readbyqxmd.com/read/28511540/effects-of-water-extractable-arabinoxylan-on-the-physicochemical-properties-and-structure-of-wheat-gluten-by-thermal-treatment
#11
Yunping Zhu, Yu Wang, Jinlong Li, Fang Li, Chao Teng, Xiuting Li
This study investigated the effects of water-extractable arabinoxylan (WEAX) on gluten by thermal treatment. Fourier transform infrared spectroscopy (FTIR) results showed that heating significantly decreased β-sheets and β-turn structures in gluten proteins between 25 and 55 °C. The addition of WEAX caused a transition from β-turn to β-sheets at >55 °C. The ratio of weakly hydrogen-bonded β-sheets to strongly hydrogen-bonded β-sheets demonstrated an increasing trend with temperature increasing, but WEAX can hinder this process...
June 14, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28494396/a-comparative-study-of-the-spectral-fluorometric-properties-and-photostability-of-natural-curcumin-iron-and-boron-complexed-curcumin
#12
Fatima Mohammed, Fiza Rashid-Doubell, Seamas Cassidy, Fryad Henari
Curcumin is a yellow phenolic compound with a wide range of reported biological effects. However, two main obstacles hinder the use of curcumin therapeutically, namely its poor bioavailability and photostability. We have synthesized two curcumin complexes, the first a boron curcumin complex (B-Cur2) and the second an iron (Fe-Cur3) complex of curcumin. Both derivatives showed high fluorescence efficiency (quantum yield) and greater photostability in solution. The improved photostability could be attributed to the coordination structures and the removal of β-diketone group from curcumin...
April 21, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28485929/trans-metal-trapping-meets-frustrated-lewis-pair-chemistry-ga-ch2sime3-3-induced-c-h-functionalizations
#13
Marina Uzelac, Alan R Kennedy, Eva Hevia
Merging two topical themes in main-group chemistry, namely, cooperative bimetallics and frustrated-Lewis-pair (FLP) activity, this Forum Article focuses on the cooperativity-induced outcomes observed when the tris(alkyl)gallium compound GaR3 (R = CH2SiMe3) is paired with the lithium amide LiTMP (TMP = 2,2,6,6-tetramethylpiperidide) or the sterically hindered N-heterocyclic carbene (NHC) 1,3-bis(tert-butyl)imidazol-2-ylidene (I(t)Bu). When some previously published work are drawn together with new results, unique tandem reactivities are presented that are driven by the steric mismatch between the individual reagents of these multicomponent reagents...
August 7, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28451271/hydroxide-bridged-five-coordinate-dy-iii-single-molecule-magnet-exhibiting-the-record-thermal-relaxation-barrier-of-magnetization-among-lanthanide-only-dimers
#14
Jin Xiong, Hai-Yan Ding, Yin-Shan Meng, Chen Gao, Xue-Jing Zhang, Zhao-Sha Meng, Yi-Quan Zhang, Wei Shi, Bing-Wu Wang, Song Gao
A hydroxide-bridged centrosymmetric Dy(III) dimer with each Dy(III) being five-coordinated has been synthesized using bulky hindered phenolate ligands. Magnetic studies revealed that this compound exhibits a slow magnetic relaxation of a single-ion origin together with a step-like magnetic hysteresis of the magnetic coupled cluster. The thermal relaxation barrier of magnetization is 721 K in the absence of a static magnetic field, while the intramolecular magnetic interaction is very large among reported 4f-only dimers...
February 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28208574/complexation-of-phytochemicals-with-cyclodextrin-derivatives-an-insight
#15
REVIEW
Vasanti Suvarna, Parul Gujar, Manikanta Murahari
Natural compounds have been attracting huge attention because of their broad therapeutic properties with specificity in their action in human health care as functional foods, pharmaceuticals and nutraceuticals. However poor bioavailability and reduced bioactivity attributed to poor solubility and instability is the major drawback hindering the incorporation of these therapeutically potential molecules in novel drug delivery systems. Based on the findings of reported research investigations; complexation of poorly water soluble phytochemicals with cyclodextrins has emerged to be a promising approach to improve their aqueous solubility, stability, rate of dissolution and bioavailability...
April 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28182626/ultrasensitive-detection-of-serum-hepatitis-b-virus-by-coupling-ultrafiltration-dna-extraction-with-real-time-pcr
#16
Bin Wu, Feng Xiao, Peiwen Li, Yan Du, Jinqiong Lin, Kaihua Ming, Bin Chen, Xiuxia Lei, Banglao Xu, Dayu Liu
BACKGROUND: A simple and reliable DNA extraction of hepatitis B virus (HBV) is critical in developing an ultrasensitive detection method for HBV infection. Current commercially available serum Hepatitis B Virus (HBV) DNA extraction methods are time-consuming, expensive and/or require specialized equipment, which hinders wide adoption of clinical laboratories. This study offers a report on an ultrasensitive HBV DNA detection method by coupling serum HBV DNA extraction by ultrafiltration (UF) with real-time PCR (qPCR) detection...
2017: PloS One
https://www.readbyqxmd.com/read/28177637/synthesis-of-the-pentacyclic-core-of-citreamicin-%C3%AE
#17
Shawn Blumberg, Stephen F Martin
The citreamicins comprise a novel class of polycyclic xanthone natural products that have not yet yielded to total synthesis. A concise 11-step synthesis of the pentacyclic core of citreamicin η is now reported that features the use of a general approach for the synthesis of 1,4-dioxygenated xanthones. The synthesis also showcases improved techniques for effecting regioselective bromination of certain substituted phenols and coupling of acetylides with hindered ketones.
February 8, 2017: Organic Letters
https://www.readbyqxmd.com/read/28004081/determination-of-the-activity-signature-of-key-carbohydrate-metabolism-enzymes-in-phenolic-rich-grapevine-tissues
#18
Elizabeth Covington Dunn, Thomas Roitsch, Marina Dermastia
Physiological studies in plants often require enzyme extraction from tissues containing high concentrations of phenols and polyphenols. Unless removed or neutralized, such compounds may hinder extraction, inactivate enzymes, and interfere with enzyme detection. The following protocol for activity assays for enzymes of primary carbohydrate metabolism, while based on our recently published one for quantitative measurement of activities using coupled spectrophotometric assays in a 96-well format, is tailored to the complexities of phenolic- and anthocyanin-rich extracts from grapevine leaf...
December 2016: Acta Chimica Slovenica
https://www.readbyqxmd.com/read/27959520/copper-catalyzed-sp-3-c-h-etherification-with-acyl-protected-phenols
#19
Tolani K Salvador, Charles H Arnett, Subrata Kundu, Nicholas G Sapiezynski, Jeffery A Bertke, Mahdi Raghibi Boroujeni, Timothy H Warren
A variety of acyl protected phenols AcOAr participate in sp(3) C-H etherification of substrates R-H to give alkyl aryl ethers R-OAr employing (t)BuOO(t)Bu as oxidant with copper(I) β-diketiminato catalysts [Cu(I)]. Although 1°, 2°, and 3° C-H bonds may be functionalized, selectivity studies reveal a preference for the construction of hindered, 3° C-OAr bonds. Mechanistic studies indicate that β-diketiminato copper(II) phenolates [Cu(II)]-OAr play a key role in this C-O bond forming reaction, formed via transesterification of AcOAr with [Cu(II)]-O(t)Bu intermediates generated upon reaction of [Cu(I)] with (t)BuOO(t)Bu...
December 28, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27872660/improvement-of-catalytic-performance-of-lignin-peroxidase-for-the-enhanced-degradation-of-lignocellulose-biomass-based-on-the-imbedded-electron-relay-in-long-range-electron-transfer-route
#20
Le Thanh Mai Pham, Su Jin Kim, Yong Hwan Kim
BACKGROUND: Although lignin peroxidase is claimed as a key enzyme in enzyme-catalyzed lignin degradation, in vitro enzymatic degradation of lignin was not easily observed in lab-scale experiments. It implies that other factors may hinder the enzymatic degradation of lignin. Irreversible interaction between phenolic compound and lignin peroxidase was hypothesized when active enzyme could not be recovered after the reaction with degradation product (guaiacol) of lignin phenolic dimer. RESULTS: In the study of lignin peroxidase isozyme H8 from white-rot fungi Phanerochaete chrysosporium (LiPH8), W251 site was revealed to make the covalent coupling with one moiety of monolignolic radical (guaiacol radical) by LC-MS/MS analysis...
2016: Biotechnology for Biofuels
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