Hydrogen Nuclear Magnetic Resonance Research Articles

Liposomal formulation of new arsenic schiff base complex as drug delivery agent in the treatment of acute promyelocytic leukemia and quantum chemical and docking calculations

The paper describes the synthesis of a new Schiff base As (III) complex followed by the encapsulation of Schiff base As (III) complex in liposomes. First, As (III) Schiff base complex was synthesized from gold crystal ligand in contact with Ascl3. Detailed characterization using Fourier transform infrared spectroscopy (FT-IR), Hydrogen-1 nuclear magnetic resonance (HNMR) and, Liquid chromatography–mass spectrometry (LC-MS) confirmed the successful synthesis of As (III) Schiff base complex. The physicochemical properties of liposomal formulations were characterized by Dynamic light scattering (DLS), Atomic force microscopy (AFM), and Transmission electron microscopy (TEM). Furthermore, Cytotoxicity results revealed higher cytotoxicity and lower IC50 for As (III) complex (2.004 μM) relative to ATO ones (3.968 μM). The expression of cell cycle genes and apoptosis were determined by Real-time technique. Moreover, the quantum chemical calculations of compounds were carried out to obtain information about the geometry and chemical reactivity by the DMol3 module in Materials studio 2017. Finally, docking calculations were performed with Formamidopyrimidine [fapy]-DNA glycosylase (Fpg) and Poly [ADP-ribose] polymerase-1 (PARP-1) to investigate the tendency of As (III) complex to bind to these two proteins. The results presented here may suggest further investigation for in vivo studies and successful targeted therapy.

Metabolic changes of the reduction of manganese intake in the hepatic encephalopathy rat: NMR- and MS-based metabolomics study.

To investigate the metabolic changes in type C hepatic encephalopathy (CHE) rats after reducing manganese (Mn) intake. A total of 80 Sprague-Dawley rats were divided into control group and CHE groups (induced by intraperitoneal injection of thioacetamide at a dose of 250mg/kg of body weight twice a week for 6 weeks). CHE rats were subdivided into 1Mn group (fed a standard diet, with 10mg Mn/kg feed), 0.5Mn group (half-Mn diet), 0.25Mn group (quarter-Mn diet) and 0Mn group (no-Mn diet) for 4 to 8weeks. Morris water maze (MWM), Y maze and narrow beam test (NBT) were used to evaluate cognitive and motor functions. Blood ammonia, brain Mn content, the number of GS-positive cells, and glutamine synthetase (GS) activity were measured. The metabolic changes of CHE rats were investigated using hydrogen-nuclear magnetic resonance and mass spectrometry. Multivariate statistical analysis was used to analyze the results. Significantly decreased numbers of entries in target area of MWM and Y maze, longer NBT latency and total time, higher blood ammonia, brain Mn content and GS activity were found in CHE rats. After reducing Mn intake, CHE rats had better behavioral performance, significantly lower blood ammonia, brain Mn content and GS activity. The main up-regulated metabolites were Ala, GABA, Glu, Gln, Lac, Tyr, Phe in 1Mn rats. After reducing Mn intake, metabolites returned to normal level at different degrees. Reducing Mn intake could reduce brain Mn content and blood ammonia, regulate GS activity and amino acid metabolism, ultimately improve behavioral performance in CHE rats.

Effects of methacrylic anhydride gelatin hydrogel loaded with silver and recombinant human basic fibroblast growth factor on deep partial-thickness burn wounds in rabbits

Effects of methacrylic anhydride gelatin hydrogel loaded with silver and recombinant human basic fibroblast growth factor on deep partial-thickness burn wounds in rabbits

Metabolic Plasticity of Candida albicans in Response to Different Environmental Conditions

The ubiquitous commensal Candida albicans, part of the human microbiota, is an opportunistic pathogen able to cause a wide range of diseases, from cutaneous mycoses to life-threatening infections in immunocompromised patients. Candida albicans adapts to different environments and survives long-time starvation. The ability to switch from yeast to hyphal morphology under specific environmental conditions is associated with its virulence. Using hydrogen nuclear magnetic resonance spectroscopy, we profiled the intracellular and extracellular metabolome of C. albicans kept in water, yeast extract–peptone–dextrose (YPD), and M199 media, at selected temperatures. Experiments were carried out in hypoxia to mimic a condition present in most colonized niches and fungal infection sites. Comparison of the intracellular metabolites measured in YPD and M199 at 37 °C highlighted differences in specific metabolic pathways: (i) alanine, aspartate, glutamate metabolism, (ii) arginine and proline metabolism, (iii) glycerolipid metabolism, attributable to the diverse composition of the media. Moreover, we hypothesized that the subtle differences in the M199 metabolome, observed at 30 °C and 37 °C, are suggestive of modifications propaedeutic to a subsequent transition from yeast to hyphal form. The analysis of the metabolites’ profiles of C. albicans allows envisaging a molecular model to better describe its ability to sense and adapt to environmental conditions.

Isolation and identification of unstable components from Caesalpinia sappan by high-speed counter-current chromatography combined with preparative high-performance liquid chromatography

Abstract Caesalpinia sappan L. (C. sappan L.), a traditional Chinese medicine, has been widely used to treat bruises and dysmenorrhea, performing pharmacological activities such as anti-inflammatory and anti-tumor. C. sappan L. has been reported to contain compounds such as protosappanins, brazilins, and homoisoflavones. In the pre-experiments, we discovered that there were many unstable components in the characteristic chromatogram of C. sappan L. Here, silica-gel column chromatography, high-speed counter-current chromatography, and preparative high-performance liquid chromatography were combined and applied to isolate the unstable components from alcohol extract of C. sappan L. The results showed that four unstable compounds were collected with the purity higher than 95.0%, characterized as episapponal, brazilin, sapponal, and 4-O-methylsapponal by hydrogen-1 and carbon-13 nuclear magnetic resonance. Based on the above results, the characteristic chromatogram of C. sappan L. was established, and the characteristic peaks were identified. These results provided a theoretical basis for the quality assessment of C. sappan L.

Separation and purification of nootkatone from fermentation broth of Yarrowia lipolytica with high-speed counter-current chromatography.

Nootkatone is an important functional sesquiterpene, which can be obtained by the biotransformation of valencene. It is increasingly important because of its pleasant citrus aroma and physiological effects. Yarrowia lipolytica is beneficial for biotechnology applications and has ability to transform valencene to nootkatone. High-speed counter-current chromatography (HSCCC) was used to isolate and purify the product of nootkatone in this study. The suitable two-phase solvent system was selected and the optimum separation conditions were determined. The partition coefficients of nootkatone and the separation factor between nootkatone and valencene were considered as the indexes. The results showed that there were numerous products during the transformation of valencene by Yarrowia lipolytica, and the content of nootkatone was 13.75%. The obtained nootkatone was separated by HSCCC with a solvent system n-hexane/methanol/water (5/4/1, v/v). The final purity of nootkatone was 91.61 ± 0.20% and the elution time was 290-310min. The structure of nootkatone was identified by gas chromatography-mass spectrometry (GC-MS), infrared spectrum and nuclear magnetic resonance hydrogen spectroscopy (1H NMR). This was the first report on the separation of nootkatone from the fermentation broth by HSCCC. This study proved that HSCCC could be used as an effective method to separate and purify the nootkatone from valencene transformed by Yarrowia lipolytica with n-hexane/methanol/water (5/4/1, v/v).

PH-Responsive Regulation of a Surfactant-Free Microemulsion Based on Hydrophobic Deep Eutectic Solvents.

Microemulsions containing a responsive hydrophobic deep eutectic solvent (HDES) as the oil phase that can replace conventional organic solvents are considered to be a green strategy. It is anticipated that a pH-responsive HDES is synthesized to prepare rapid responsive surfactant-free microemulsions (SFMEs), which enable the transition from SFMEs to nanoemulsions. Menthol and n-octanoic acid (OA) were assembled into HDES by hydrogen bonding at a molar ratio of 1:2. The pH-responsive HDES as the oil phase and isopropyl alcohol (IPA) as the double solvent could form HDES/IPA/water SFMEs, which have unique responsiveness. Specifically, from the nuclear magnetic resonance hydrogen spectrum, pH, thermogravimetry, and Fourier transform infrared spectroscopy investigations, the excellent switchability and stability of menthol-OA were demonstrated. On the basis of these complexes, microemulsions were successfully prepared. Electrical conductivity and pH measurements were used to determine the structures of microemulsions and the phase inversion process. The effects of the contents of water and HDES, NaCl concentration, and pH of the system were investigated. Nanoemulsions were successfully prepared on the basis of the pH response of the microemulsions. In addition, the prepared nanoemulsion has a unique pH-responsive behavior that can be controllably regulated among nanoemulsions, microemulsions, and phase separation systems.

Synthesis of tung oil-based vinyl ester resin and its application for anti-corrosion coatings

Anti-corrosion coatings are of great significance for marine equipment and engineering on account of the harsh marine environment. Vinyl ester resin is widely used as a resin material for anti-corrosion coating because of its excellent hardness and protective performance. However, the intrinsic brittleness of vinyl ester resin causes the resulting coating film with poor toughness. In this study, the tung oil-based toughen modifier (TOAMA) with a long carbon chain and annular structure is firstly prepared by Diels-Alder reaction of tung oleic acid and maleic anhydride under solvent-free conditions, and then used as a reactive toughening agent to synthesize toughened vinyl ester resin. The characterization results of Fourier transform infrared and hydrogen nuclear magnetic resonance spectroscopies reveal the successful synthesis of the TOAMA-toughened vinyl ester resin. Furthermore, the toughened vinyl ester resin is used in the anti-corrosion coatings, and the properties of the related cured coating films including thermostability, mechanical performance and corrosion resistance are systematically studied. The related results display that TOAMA can effectively toughen vinyl ester resin, and the toughened vinyl ester resin prepared with the optimized TOAMA content can effectively improve the mechanical properties including mechanical strength, elongation at break and fracture toughness, and achieve favorable thermal stability and excellent corrosion resistance of the cured coating films. Grafting tung oil-based toughening modifier TOAMA into the backbone of vinyl ester resin effectively provides a significant promising method to toughen vinyl ester resin, which is beneficial to the application of vinyl ester resin in the marine anti-corrosion coating field.

Investigation of thermal, antibacterial and heavy metal ion removal behavior of polyamide/polyimide iron oxide nanocomposites

In this study, a newly-designed diamine (DA) containing pyridine and carbazole groups was synthesized and the relevant polyamides (PAs) and polyimides (PIs) were prepared by polymerization reaction between the DA monomer and terephthalic acid, adipic acid, and pyromellitic dianhydride. In addition, polymer nanocomposites were prepared through a combination of the synthesized polymers with modified magnetite iron oxide nanoparticles. The synthesized compounds were fully characterized by hydrogen nuclear magnetic resonance (1HNMR), fourier-transform infrared (FTIR), field emitting scanning electron microscopy (FESEM), energy dispersive X-Ray (EDX), Transmission electron microscopy (TEM), Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA) analyses. All of the synthesized properties of compounds such as thermal stability, viscosity, elimination capability of heavy metals ions adsorption, and antibacterial activity were investigated. Polyamides and PI showed good solubility in aprotic solvents and the viscosity was in the range of 0.72–0.89 dL/g. Also, the glass-transition temperature (Tg) of synthetic polymers was in the range of 214–273°C and 10% weight loss temperatures (T10%) for the synthesized compounds were in the temperature range of 280–492°C in N2, and the percentage of residual ash between 61 and 74%. The adsorption rate of Hg2+, Co2+, Pb2+, Cr2+, and Cd2+ metal ions by PA containing terephthalic acid (PAT) and its nanocomposite (NCPAT) showed that nanocomposite has a better performance compared to PAT. The highest and lowest removal efficiency was related to Hg2+ and Pb2+ ion, respectively. Finally, antibacterial test results against Gram-positive and Gram-negative bacteria showed favorable inhibitory effects of all the synthesized polymers.

A Temperature-Sensitive Polymeric Rheology Modifier Used in Water-Based Drilling Fluid for Deepwater Drilling.

Rheology modifiers are essential for the flat rheology of water-based drilling fluids in deepwater. The low temperature thickening of deepwater water-based drilling fluids results in dramatic rheological changes in the 20–30 °C range. To address such problems, NIPAM with a self-polymerized product LCST of 32–35 °C was selected as the main body for synthesis. While introducing the hydrophilic monomer AM to enhance the thickening properties, the hydrophobic monomer BA was selected to reduce the LCST of the product. In this paper, a temperature-sensitive polymeric rheology modifier (PNBAM) was synthesized by emulsion polymerization using N-isopropyl acrylamide, acrylamide, and butyl acrylate as monomers. The PNBAM was characterized using infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and nuclear magnetic resonance hydrogen spectroscopy (NMR). The rheological properties, temperature resistance, and salt resistance of PNBAM in the base fluid (BF) were tested. The performance of PNBAM in the drilling fluid system was also evaluated, and a water-based drilling fluid system of flat rheology for deepwater was formulated. The rheological modification mechanism of PNBAM was analyzed by turbidity analysis, particle size analysis, and zeta analysis. Experimental results show that PNBAM has good rheological properties. PNBAM is temperature resistant to 150 °C, salt-resistant to 30 wt%, and calcium resistant to 1.0 wt%. PNBAM also has good flat rheology characteristics in drilling fluid systems: AV4°C:AV25°C = 1.27, PV4°C:PV25°C = 1.19. Mechanistic analysis showed that the LCST (Lower Critical Solution Temperature) of 0.2 wt% PNBAM in an aqueous solution was 31 °C. Through changes in hydrogen bonding forces with water, PNBAM can regulate its hydrophilic and hydrophobic properties before and after LCST, which thus assists BF to achieve a flat rheological effect. In summary, the temperature-sensitive effect of PNBAM has the property of enhancing with increasing temperature. While the tackifying effect of conventional rheology modifiers diminishes with increasing temperature, the temperature-sensitive effect of PNBAM gives it an enhanced thickening effect with increasing temperature, making it a more novel rheology modifier compared to conventional treatment additives. After LCST, compared to conventional rheology modifiers (XC), PNBAM has a more pronounced thermo-thickening effect, improving the main rheological parameters of BF by more than 100% or even up to 200% (XC less than 50%). This contributes to the flat rheology of drilling fluids. PNBAM has good application prospects and serves as a good reference for the development of other rheology modifiers.

Determination of in situ hydrocarbon contents in shale oil plays. Part 1: Is routine Rock–Eval analysis reliable for quantifying the hydrocarbon contents of preserved shale cores?

An accurate determination of in situ hydrocarbon (oil) content is critical for the assessment of shale oil plays in terms of their total resources in place and recovery potential. Although correction of light hydrocarbon loss to the Rock–Eval S1 parameters on conventional core and cuttings samples has been recently attempted using preserved (e.g., sealed or pressure–preserved) cores, hydrocarbon evaporation loss during sample preparation and delay time before the actual commencement of Rock–Eval analysis has not received sufficient attention. In this study, a combination of petrophysical and geochemical techniques including Dean–Stark extraction, hydrogen nuclear magnetic resonance (1H-NMR) T1-T2 mapping, thermal desorption–gas chromatography (TD–GC) analysis, and Rock–Eval programmed pyrolysis were used in parallel on a set of 30 preserved shale cores to determine their total hydrocarbon contents. The preserved shale cores were analyzed in large pieces (e.g., 3–5 cm in size) by the former two petrophysical methods while using fine powder (e.g., <60 mesh) by the latter two thermal analytical methods. The total free hydrocarbon contents (equivalent of Rock–Eval S1) determined on the studied lacustrine shale samples with a Ro ranging from 1.00% to 1.51% followed the order of Dean–Stark (average 10.27 mg/g) ≈ NMR (10.34) ＞ TD–GC (6.65) ＞ Rock–Eval (3.93). The core crushing and grinding process required for both TD-GC and Rock–Eval pyrolysis analyses was found to cause a loss of approximately 35% to the in situ hydrocarbons. In addition, Rock–Eval analysis delay time (of 5 min) could lead to another 25% reduction to the total free hydrocarbons. In combination, sample preparation and analysis delay resulted in up to 60% reduction to the Rock–Eval S1 peaks for the preserved shale cores, and a 30% loss to the liquid (C6+) hydrocarbons in particular. To the best of our knowledge, this is the first reported observation that in situ light hydrocarbon contents can be severely underestimated by Rock–Eval and TD–GC analyses using powdered forms of preserved core samples. The extents of light hydrocarbon loss in conventional cores have been underestimated using the Rock–Eval S1 difference between preserved shale and its long–duration exposed replicates. Hence, when quantifying the hydrocarbon contents of the preserved shale samples, techniques utilizing larger rock pieces are highly recommended.

Study on molecular structure and association behaviour of heavy subfractions of vacuum residue by an improved separation method

AbstractVacuum residue (VR) is the most complex component of crude oil. Due to the special structure of heavy subfractions, physical aggregation and chemical coking reactions easily occur through molecular force, which affects the normal processing. Therefore, in‐depth study and analysis of their composition, structure and association behaviours are particularly important. In view of the shortcomings of the traditional separation method in terms of separation accuracy, mainly including the purification of asphaltenes and the poor separation of resins. In this paper, a reasonably improved separation method is adopted, and the multi‐stage asphaltene extraction and the multi‐stage silica gel coupling separation are carried out innovatively, which achieves a high yield of 99% while ensuring the separation accuracy. The samples were characterized by elemental analysis (EA), gel permeation chromatography (GPC), Fourier‐transform infrared spectroscopy (FT‐IR), hydrogen nuclear magnetic resonance spectroscopy (1H‐NMR), X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD), and scanning electron microscope (SEM) to study their structural characteristics and association behaviours. The results show that the main forms of heteroatoms in asphaltene and resin surface are C‐O‐C, C‐OH, pyridine, pyrrole, and thiophene, and the content of these substances is higher in asphaltene. Compared with resins, asphaltenes contain a more peri‐condensed aromatic structure and shorter alkyl substituent side chains. By studying the hydrogen bond and acid–base interaction, it is found that asphaltene and resin mainly contain OH‐OH, OH‐π, and OH‐ether O, of which the content of OH‐OH is the highest. Asphaltene and resin have more neutral and basic substances. These hydrogen bonds and acid–base interactions caused by heteroatoms are the main forces for the association of the heavy subfractions of the VR.

High-efficiency two-dimensional separation of natural products based on β-cyclodextrin stationary phase working in both hydrophilic and reversed hydrophobic modes

Natural products are rather complex samples containing a large number of compounds ranging from polar to nonpolar, small molecules to macromolecules, as well as numerous homologs/analogs with quite similar structures, which create great opportunities and treasures for discovery of bioactive drugs. For the purpose of better understanding the complex natural products and controlling their qualities, powerful analytical techniques for adequately separating chemical constituents and tracking potentially bioactive components are quite essential. Here, a design concept of bidirectional β-cyclodextrin (β-CD)–modified chromatographic stationary phase toward separation of bufadienolides extracted from toad is proposed. Bufadienolides could be divided into two classes: toad venom ligand (AAUBs) and toad toxin (AACBs) with remarkable differences in structures and polarity. The hydrophobic cavity of β-CD can encapsulate the steroid part of AACBs while the hydroxyls exposed on the β-CD surface have strong hydrophilic interactions with the arginine part of AACBs. Isothermal titration calorimetry and hydrogen nuclear magnetic resonance titration experiment further validate the rationality of this design. Furthermore, the β-CD-based stationary phase can be used as a hydrophilic material to construct a HILIC × RPLC 2D separation mode for the separation of AACBs, also works as a reverse phase material to construct a RPLC × RPLC 2D separation mode for the separation of AAUBs with good orthogonality. This study will open an avenue and provide a novel insight for high-efficiency two-dimensional separation of natural products.

Synthesis of diethanolamine-based amino acid derivatives with symmetric and asymmetric radicals in their hydrophobic domain and potential antimicrobial activity

Objectives. Resistance to antibiotics and other antimicrobial drugs is an acute problem in the world today. Therefore, the chemical and pharmaceutical industries are still in search of new antibacterial agents that can overcome the resistance of pathogenic bacterial strains. To date, it has been established that molecules with antimicrobial activity must have an amphiphilic nature, a small size, one or more positive charges, and the required degree of hydrophobicity, that is, a significant hydrophilic–lipophilic balance (HLB) value. Some examples of such structures are antimicrobial peptides or peptidomimetics. This study aimed to develop a universal scheme for synthesizing several amino acid derivatives based on diethanolamine diesters with symmetric and asymmetric radicals in a hydrophobic block and potential antibacterial activity.Methods. The progression of chemical reactions was analyzed using thin-layer chromatography (TLC) on Sorbfil plates. The obtained compounds were isolated and purified using preparative TLC on Kieselgel (Merck) 60 F254 plates and column chromatography on Merck silica gel 0.040–0.063 mm. The TLC method was used to detect substances using a 3% ninhydrin solution, followed by heating to 70 °C. The structures of the obtained compounds were confirmed by hydrogen-1 nuclear magnetic resonance (1H NMR) spectroscopy on a Bruker WM-300 pulse NMR spectrometer, with hexamethyldisiloxane serving as the internal standard.Results. The HLB values of the diethanolamine derivatives were calculated, and samples were selected for subsequent synthesis. A scheme was developed for preparing amino acid derivatives based on diethanolamine diesters with symmetric and asymmetric radicals in the hydrophobic domain, and five new compounds were synthesized. The hydrophilic blocks of these compounds included residues of amino acids such as glycine, β-alanine, L-ornithine, and L-lysine.Conclusions. The potential antimicrobial activity of the synthesized peptidomimetics was assessed by their HLB values using the ACD/Labs Log P program. New amphiphiles were synthesized using amino acids and diethanolamine, and their structures were confirmed by 1H NMR spectroscopy data. The synthesized compounds were prepared for antibacterial activity analysis.

Phytochemical and antiplasmodial evaluation of five Colombian plants with ethnopharmacological background of antimalarial use

Background: The study of medicinal plants has made it possible to develop products and drugs for the treatment of different diseases. Several plants in Colombia have a history of popular use for the treatment of malaria. The objective of this work was to provide information on the antiplasmodic and phytochemical activity of five neotropical native plants with a folk use for the treatment of malarial.Methods: The ethanolic extract of each species was obtained by percolation method and characterized by TLC, HPLC, and 1H-NMR. The in vitro antiplasmodial activity was evaluated against Plasmodium falciparum (strain FCR-3, chloroquine-resistant).Results: Ethanolic extracts of Ambelania duckey, Cecropia metensis, Cecropia membranacea, and Verbena littoralis showed no activity. However, Curarea toxicofera extract exhibited an IC50 of 7.6 ± 3.9 μg/mL and was classified as moderately active. Furthermore, hemolytic activity was assayed, none of the extracts were tested positive. A preliminary phytochemical study was carried out using tube analysis, thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), and hydrogen nuclear magnetic resonance (1H-NMR). Steroids or triterpenes, and phenolic compounds were detected by TLC in all extracts. These findings were confirmed by characteristic aliphatic and aromatic signals in 1H-NMR spectra, corresponding to triterpenes and phenolics, respectively. Additionally, alkaloids were extracted from C. toxicofera and detected by aromatic signals in 1H-NMR spectra.Conclusion: ethanolic extract of C. toxicofera showed antiplasmodial activity (IC50 of 7.6 ± 3.9 μg/mL); this activity may be due to the bisbenzylisoquinoline alkaloids. The ethanol extracts of A. duckey, C. membranacea, C. metensis, and V. littoralis did not present antiplasmodial activity.

Oral magnesium sulphate administration in rats with minimal hepatic encephalopathy: NMR-based metabolic characterization of the brain

To investigate the metabolic changes in rats with minimal hepatic encephalopathy (MHE) treated with oral magnesium sulphate administration. A total of 30 Sprague-Dawley rats were divided into a control group and MHE group (further divided into an MHE group and an MHE-Mg group treated with oral administration of 124 mg/kg/day magnesium sulphate). Morris water maze (MWM), Y maze and narrow beam walking (NBW) were used to evaluate cognitive and motor functions. Brain manganese and magnesium content were measured. The metabolic changes in rats with MHE were investigated using hydrogen-nuclear magnetic resonance. Metabolomic signatures were identified with enrichment and pathway analysis. A significantly decreased number of entries into the MWM within the range of interest, longer latency and total time during NBW, and higher brain manganese content were found in rats with MHE. After magnesium sulphate treatment, the rats with MHE had better behavioural performance and lower brain manganese content. The 25 and 26 metabolomic signatures were identified in the cortex and striatum of rats with MHE. The pathway analysis revealed alanine, aspartate and glutamate metabolism as the major abnormal metabolic pathways associated with these metabolomic signatures. Alanine, aspartate and glutamate metabolism are major abnormal metabolic pathways in rats with MHE, which could be restored by magnesium sulphate treatment.

Syntheses, Characterizations, and Inhibition Activities Against Coxsackievirus B3 of Iodobenzoic Hydrazide Functionalized Hexamolybdates.

A class of iodobenzoyldiazenido-functionalized POMs (TBA)3 [Mo6O18(=N=NCOAr)] (Ar = Ph-o-I (1); Ph-m-I (2); Ph-p-I (3); Ph-3,4-I2 (4); Ph-2,3,5-I3 (5) (TBA = tetrabutylammonium) were prepared via the refluxing reaction of α-octamolybdates, DCC, and corresponding hydrazides in dry acetonitrile. Their structures were determined by Fourier-transform infrared spectroscopy, ultraviolet–visible spectra, X-ray photoelectron spectroscopy, hydrogen-1 nuclear magnetic resonance, and high-resolution mass spectrometry. Research on the biological activity of title compounds shows that L3, L5, 3, and 5 demonstrate potent inhibitory activity against coxsackievirus B3 and low in vitro cytotoxic activity against Hep-2 cell lines. The covalent linkage between the iodobenzoyldiazenido components and POMs can enhance the molecular inhibitory efficiency of iodobenzohydrazides.

Ultrasonic Assisted Extraction of Quinoa (Chenopodium quinoa Willd.) Protein and Effect of Heat Treatment on Its In Vitro Digestion Characteristics.

To extract and utilise the protein in quinoa efficiently, we investigated the effect of rate of quinoa protein isolate (QPI) extraction by ultrasound-assisted alkaline extraction and traditional alkaline extraction methods using single-factor experiments and Box-Behnken design. The effect of different heat treatment temperature and time on QPI functional properties and in vitro digestion characteristics were also investigated. The results showed that the optimal conditions of ultrasound- assisted alkaline extraction process were: ultrasonic time 99 min, solid-liquid ratio 1:20 w:v, ultrasonic temperature 47 °C, and pH 10, and its extraction rate and purity were 74.67 ± 1.08% and 87.17 ± 0.58%, respectively. It was 10.18% and 5.49% higher than that of the alkali-soluble acid precipitation method, respectively. The isoelectric point (pI) of QPI obtained by this method was 4.5. The flexibility and turbidity of QPI had maximum values at 90 °C, 30 min, and 121 °C, 30 min, which were 0.42 and 0.94, respectively. In addition, heat treatment changed the 1.77–2.79 ppm protein characteristic region in QPI’s nuclear magnetic resonance hydrogen spectroscopy (1H NMR). After heating at 90 °C and 121 °C for 30 min, the hydrolysis degree and total amino acid content at the end of digestion (121 °C, 30 min) were significantly lower than those of untreated QPI by 20.64% and 27.85%. Our study provides basic data for the efficient extraction and utilisation of QPI.

Ferulic acid derivatives inhibiting Staphylococcus aureus tetK and MsrA efflux pumps

Bacterial resistance to multiple drugs has recently emerged as a serious health problem. Concomitantly, the characterization of new substances with potential antimicrobial activity has been less frequent in the drug development industry. The overexpression of genes encoding efflux pumps that expel antimicrobial drugs from the intracellular environment, lowering these to subinhibitory concentrations, are among the resistance mechanisms predisposing microorganisms to high drug resistance. Staphylococcus aureus is a bacterium found in the normal microbiota of the skin and mucous membranes, and is an opportunistic microorganism capable of causing infections with high rates of morbidity and mortality. TetK is an efflux pump characterized by its ability to provide bacterial resistance to antibiotics from the tetracycline class. This study aimed to evaluate the inhibitory effect of ferulic acid and four of its esterified derivatives against resistant Staphylococcus aureus strains. Ferulic acid derivatives were obtained by esterification and then characterized by hydrogen and carbon-13 nuclear magnetic resonance analysis. The minimum inhibitory concentrations (MIC) of ferulic acid and its esterified derivatives, ethidium bromide, and antibiotics were obtained using the microdilution test, while the efflux pump inhibition test was conducted by examining reduction in the MICs. Propylferulate was seen to reduce the minimum inhibitory concentration (MIC) of both the control substance ethidium bromide and the tested antibiotic, indicating that this compound is promising for the use of efflux pump inhibition of IS-58 strains. This study provides strong evidence that the molecular basis for this activity is potentially due to the MsrA and TetK efflux pumps. However, further investigations are necessary to prove this hypothesis and elucidate the potentiating mechanism of the modulatory effect.

Synthesis of renewable soybean protein and acrylate copolymers via ATRP in ionic liquid

In this paper, acrylate and glycidyl methacrylate (GMA) were grafted onto the main chain of soy protein isolate (SPI) in 1-butyl-2,3-dimethylimidazole chloride ionic liquid ([BDMIM][Cl]), to prepare a renewable soy protein graft copolymer via atom transfer radical polymerization (ATRP). The effect of unfolding degree of soy protein structure on pretreated SPI was studied via Fourier-transform infrared spectroscopy (FT-IR), hydrogen nuclear magnetic resonance spectroscopy (1 H NMR), surface tension (ST) and contact angle (CA) measurements. The results of FT-IR, 1 H NMR and energy dispersive spectrometry (EDS) indicated the successful synthesis of 2-bromoisobutyryl-functionalized SPI.The analysis of FT-IR and 1H NMR spectra showed that the soybean protein graft copolymer was successfully synthesized. In addition, the grafting of acrylate onto soybean protein enhanced the hydrophobicity of the copolymer, and the static contact angle was above 90°. Differential scanning calorimetry (DSC) analysis revealed that the thermal stability of pretreated SPI was reduced. The new glass transition temperature in the copolymers also proved the successful synthesis of the copolymers. The tensile strength of the carbon fiber multifilament infiltrated with the copolymers was improved, indicating their potential application in the reinforcement of carbon fiber material.