1H Nuclear Magnetic Resonance Research Articles

Nuclear Magnetic Resonance Spectroscopic Characterization and Determination of the New Psychoactive Substance Benzylone: Application in a Biological Fluid.

New psychoactive substances (NPS)-designed to mimic various legal or illegal substances-are an emerging worldwide health problem. Their identification and quantification in either complex seized samples or powders are critical; moreover, their determination in biological fluids is an intriguing goal in the forensic toxicology field. Synthetic cathinones are one of the most important groups among NPS. The current paper was designed as a pilot study to investigate the application of NMR techniques to identify and quantify unknown NPS compounds in deuterated dimethyl sulfoxide (DMSO-d6) and in urine using the synthetic cathinone benzylone (3,4-methylenedioxy-N-benzylcathinone, BMDP) as a pilot compound. In the first part of our study, nuclear magnetic resonance (NMR) spectroscopic characterization was performed using 1D and 2D homonuclear and heteronuclear NMR spectroscopic methods as long as diffusion ordered spectroscopy (DOSY). Following the above, the assignment of benzylone in DMSO-d6 was performed, and a distinct spectroscopic pattern was proposed. In the second part of our study, a NMR spectroscopic approach was applied for benzylone identification and quantification in a spiked with benzylone urine. Following the above, the assignment of benzylone in spiked urine was performed. A distinct pattern of the H11, H14, H15, and H8 signals on the 1H NMR spectra was observed and suggested as a "NMR spectroscopic pattern/signature" enabling the identification of benzylone moieties in urine. On the other hand, the applied NMR techniques showed low sensitivity in quantitating benzylone in spiked urine. Overall, our results are promising in using NMR for structure determination of unknown compounds in urine.

Application of 1H NMR Metabolic Profiling of Serum in Canine Multicentric Lymphoma.

Canine lymphoma represents a biologically and metabolically heterogeneous group of neoplasms that arise from malignant transformation of lymphoid cells. An accurate diagnosis is crucial because of its impact on survival. Current diagnostic methods include clinical laboratory tests and imaging, most of which are invasive and lack sensitivity and specificity. Interestingly, recent work in cancer patients focuses on the search for biomarkers for diagnosis, investigation of treatment response mechanisms, treatment efficacy and prognosis and the discovery of tumour metabolic pathways using metabolomic analysis. In this study, we compare the metabolite profiles in serum from 37 dogs with multicentric lymphoma (22 B-cell lymphomas/LB, 9 CD45+ T-cell lymphomas/LTCD45+, 6 CD45- T-cell lymphomas/LTCD45-) and 25 healthy dogs using 1H nuclear magnetic resonance spectroscopy (NMR). 1H NMR-based metabolite profiling analysis recognised lipids and 22 metabolites, with 16 of them altered, and was shown to be an effective approach for differentiating samples from dogs with lymphoma and healthy controls based on principal component analysis of the NMR data. We also investigated variations in the serum metabolome between immunophenotypes and the control group through pairwise comparisons of the healthy against the LB, LTCD45+ and LTCD45- groups, respectively which showed similar metabolomic profiles. In addition, there were significant differences in the levels of five individual metabolites based on the univariate statistical analysis. Our results showed alterations in energy, protein and lipid metabolism, suggesting glucose, lactate, N-acetyl glycoproteins (NAGs), scyllo-inositol and choline as possible new candidate biomarkers in canine multicentric lymphoma.

Determination of the structure of a new potentially active pharmaceutical substance

Introduction. The development of methods for analyzing new potentially active pharmaceutical substances is an important part of substance standardization. An integrated approach to confirming the structure of a substance is especially important when the substance may exist in different tautomeric forms, since the properties of the substance may change depending on tautomerism, affecting, among other things, the pharmacological activity.Aim. The aim of our study was to determine the tautomeric composition of the potential active pharmaceutical substance 5-butyl-6-hydroxy-2,3-diphenylpyrimidin-4(3H)-one in solid state and solution for the subsequent development of its dosage form and determination of bioavailability.Material and methods. The object of the study was the substance 5-butyl-6-hydroxy-2,3-diphenylpyrimidin-4(3H)-one. Spectra were taken to confirm the structure: infrared on a PerkinElmer Spectrum 3 device (PerkinElmer Inc., USA) in the frequency range from 4000 to 400 cm–1, nuclear magnetic resonance 1H and 13C on a pulsed broadband spectrometer Bruker AM-500 (400 and 100 MHz) (Bruker, Germany) in DMSO-d6 solvent, ultraviolet using SF-2000 (LLC "OKB Spektr", Russia) in the wavelength range of 250–400 nm, and high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) was also carried out.Results and discussion. A feature of pyrimidine hydroxy derivatives is the presence of tautomeric forms, which can affect both the physicochemical properties of the substance and its pharmacological activity. The study found that in the solid state, 5-butyl-6-hydroxy-2,3-diphenylpyrimidin-4(3H)-one is in equilibrium between the diketo form and the enol form, and when the substance is dissolved in dimethyl sulfoxide (DMSO), the enol form is predominant. The purity was confirmed by HPLC-MS/MS.Conclusion. The structure of 5-butyl-6-hydroxy-2,3-diphenylpyrimidin-4(3H)-one was confirmed by IR and NMR spectroscopy. UV spectra were obtained, and HPLC-MS/MS was performed to exclude possible absorption of ultraviolet radiation by impurities.

Boosting 1H and 13C NMR signals by orders of magnitude on a bench.

Sensitivity is often the Achilles' heel of liquid-state nuclear magnetic resonance (NMR) experiments. This problem is perhaps most pressing at the lowest fields (e.g., 80-MHz 1H frequency), with rapidly increasing access to NMR through benchtop systems, but also sometimes for higher-field NMR systems from 300 MHz to 1.2 GHz. Hyperpolarization by dissolution dynamic nuclear polarization (dDNP) can address this sensitivity limitation. However, dDNP implies massive and complex cryogenic and high-field instrumentation, which cannot be installed on the bench. We introduce here a compact helium-free 1-T tabletop polarizer as a simple and low-cost alternative. After freezing and polarizing the frozen analyte solutions at 77 K, we demonstrate 1H signal enhancement factors of 100, with rapid 1-s buildup times. The high polarization is subsequently transferred by 1H→13C cross polarization (CP) to 13C spins. Such a simple benchtop polarizer, in combination with hyperpolarizing solid matrices (HYPSOs), may open the way to replenishable hyperpolarization throughout multiple liquid-state NMR experiments.

Design, synthesis, X-ray crystal structure, and antifungal evaluation of new acetohydrazide derivatives containing a 4-thioquinazoline moiety.

To find efficient agricultural fungicides, 29 new 4-thioquinazoline-containing acetohydrazide derivatives were prepared and tested for their fungicidal properties. All of the target compounds were characterized by 1H and 13C nuclear magnetic resonance and high-resolution mass spectrometry techniques, and the molecular structure of compound A2 was verified by single-crystal X-ray diffraction measurement. The experimental results revealed that many compounds from this series had impressive inhibition efficacies in vitro against the tested fungi. For example, compound A25 was identified as the best fungicidal agent against Rhizoctonia solani with an EC50 (half-maximal effective concentration) value of 0.66 μg mL-1, superior to those of the commercial fungicides chlorothalonil, carbendazim and boscalid. Additionally, this compound displayed favorable protection and curative activities in vivo against rice sheath blight caused by R. solani. Antifungal mechanistic studies on compound A25 indicated that this compound exerted its strong anti-R. solani effects probably through an effective inhibition of fungal succinate dehydrogenase activity [half-maximal inhibitory concentration (IC50) = 4.88 μm] and the impairment of cell membrane integrity, based on the results from enzymatic bioassays, molecular docking studies, and scanning and transmission electron microscopy observations. Acetohydrazide derivatives containing the 4-thioquinazoline moiety had the potential to be employed as lead compounds for developing more efficient agricultural fungicides in the near future. © 2024 Society of Chemical Industry.

Gut Microbiota and Related Metabolites in Children With Egg White Sensitization.

We hypothesized that food sensitization in children could be linked to specific gut microbiota. The objective of this study is to assess a group of children with egg white sensitization (ES) from the microbiological and biochemical-metabolic standpoint, applying the microbiota and metabolomics approach to studying the intestinal contents of the feces. Twenty-eight toddlers with ES (mean age 13.08 months) and 24 healthy controls (mean age 12.85 months) were recruited for feces collection, serum IgE measurement, gut microbiota and metabolomics analysis. Individual microbial diversity and composition were analyzed via targeting the 16S rRNA gene hypervariable V3-V5 regions. The metabolite profiles of human feces were explored by 1H nuclear magnetic resonance. Children with ES exhibited relatively high levels of Firmicutes at the phylum level and relatively low levels of Bacteroidetes. Moreover, children with ES exhibited significantly reduced overall gut microbiota diversity and richness compared with healthy children. At the family level, we observed significant increases in the numbers of Clostridiaceae, Lachnospiraceae, Pasteurellaceae and Ruminococcaceae in children with ES. Egg white sensitivity increases orotic acid, nicotinate, methyl succinate, urocanic acid, xanthine, amino acids (tyrosine, lysine, tryptophan, phenylalanine) and short-chain fatty acids (n-butyrate, valerate) levels according to the results of metabolomics analysis. In summary, some specific families and genera (dysbiosis) are enriched in the gut microbiota, and increases in the mean concentrations of organic compounds in the fecal metabolite profile are associated with ES in children. These findings may provide evidence of potential strategies to control the development of ES or other atopies by modifying the gut microbiota.

Use of a hydrosilylation reaction for the preparation of structure-controlled boroxine-based polyborosiloxanes

The structure of organosilicon vinyl-containing boroxine was confirmed by 1H nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. Its thermal properties were studied using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) methods. The ability of boroxine to undergo hydrosilylation using the Karstedt's catalyst was investigated on various organosilicon substrates. Boroxine was shown to be involved in these reactions as a cross-linking agent. The formation of dynamic boroxine cross-links allowed the analysis of the reaction products by NMR spectroscopy, including the use of polyfunctional hydride-containing reagents. In all cases the addition proceeds selectively to the β-position and with complete conversion. The structure of the resulting polyborosiloxane containing 1.4 mol% of modified units was also confirmed by 1H NMR spectroscopy, and its thermal and rheological properties were studied.

Synthesis of Chalcones, Screening In silico and In vitro and Evaluation of Helicobacter pylori Adhesion by Molecular Docking.

We synthetized 10 hydroxylated and methoxylated chalcones and evaluated them targeting MMP-9 inhibition, looking for the rate of adhesion of H. pylori in gastric cells, and then, reduction of the inflammatory response as alternative therapeutic agents for controlling the infection. Helicobacter pylori is a Gram-negative bacterium that chronically infects the human stomach, a risk factor for the development of inflammatory gastrointestinal diseases, including cancer, and is classified as a group I carcinogen. It is estimated that it infects around 45% of the global population and that the persistence of the infection is related to the adhesion of the bacteria in the gastric epithelium. The progression of gastric lesions to cancer is connected to the activation of the NF-κB and MAPK pathways, especially in cagA+ strains, which are related to increased expression of MMP-9. The activation of these metalloproteinases (MMPs) contributes to the adhesion of the bacterium in gastric cells and the evolving stages of cancer, such as enabling metastasis. Due to the increasing resistance to the current therapy protocols, the search for alternative targets and candidate molecules is necessary. In this way, controlling adhesion seems to be a suitable option since it is a crucial step in the installation of the bacterium in the gastric environment. Synthetize ten hydroxylated and methoxylated chalcones. Assess their anti-H. pylori potential, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). Evaluate their cytotoxicity in AGS cells and selectivity with L-929 cells. Analyze the results and correlate them with in silico predictions to evaluate potential anti-adhesive properties for the chalcones against H. pylori. The chalcones were synthetized by Claisen-Schmidt condensation using Ba(OH)2 or LiOH as catalysts. Predictive in silico assays in PASS Online, tanimoto similarity, ADME properties and molecular docking in MMP-9 (PDB code: 6ESM) were performed. The in vitro assays carried out were the cell viability in gastric adenocarcinoma cells (AGS) and fibroblasts (L-929) by the MMT method and anti-H. pylori, by the broth microdilution method, through the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Ten chalcones were synthesized through Claisen-Schimdt condensation with yields of 10 to 52% and characterized by 1H and 13C nuclear magnetic resonance (NMR) and mass spectrometry (MS). in silico data revealed the possibility of anti-H. pylori, anti-inflammatory, and MMP-9 inhibition for the chalcones. Chalcone 9 showed the best growth inhibition values for MIC and MBC, at 1 μg/mL and 2 μg/mL, respectively. Chalcones 14 and 15 likewise demonstrated excellent inhibitory results, being 2 μg/mL for both MIC and MBC. Additionally, 15 had the best MMP-9 inhibition score. Despite not corroborating the in silico findings, chalcones 10, 13, and 18 showed good cytotoxicity and the best selectivity indices. All compounds exhibited strong activity against H. pylori, specially 15. The predicted MMP-9 inhibition by molecular docking added to the reasonable SI and CI50 values for 15 and the satisfactory reduction in the rate of survival of the bacteria, reveals that it may be acting synergically to reduce the inflammatory response and the possibilities for developing a tumor by inhibiting both bacteria and malignant cells.

Structure and Biosynthetic Gene Cluster of Sulfated Capsular Polysaccharide from the Marine Bacterium Vibrio sp. KMM 8419

Vibrio sp. KMM 8419 (=CB1-14) is a Gram-negative bacterium isolated from a food-net mucus sample of marine polychaete Chaetopterus cautus collected in the Sea of Japan. Here, we report the structure and biosynthetic gene cluster of the capsular polysaccharide (CPS) from strain KMM 8419. The CPS was isolated and studied by one- and two-dimensional 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The molecular weight of the CPS was about 254 kDa. The CPS consisted of disaccharide repeating units of D-glucose and sulfated and acetylated L-rhamnose established as →2)-α-L-Rhap3S4Ac-(1→6)-α-D-Glcp-(1→. To identify the genes responsible for CPS biosynthesis, whole-genome sequencing of KMM 8419 was carried out. Based on the genome annotations together with the Interproscan, UniProt and AntiSMASH results, a CPS-related gene cluster of 80 genes was found on chromosome 1. This cluster contained sets of genes encoding for the nucleotide sugar biosynthesis (UDP-Glc and dTDP-Rha), assembly (glycosyltransferases (GT)), transport (ABC transporter) and sulfation (PAPS biosynthesis and sulfotransferases) of the sulfated CPS. A hypothetical model for the assembly and transportation of the sulfated CPS was also proposed. In addition, this locus included genes for O-antigen biosynthesis. Further studies of biological activity, the structure–activity relationship in the new sulfated polysaccharide and its biosynthesis are necessary for the development of potent anticancer agents or drug delivery systems.

Rhamnolipid-Enriched PA3 Fraction from Pseudomonas aeruginosa SWUC02 Primes Chili Plant Defense Against Anthracnose

Chili anthracnose, caused by Colletotrichum truncatum, causes significant yield loss in chili production. In this study, we investigated the elicitor properties of a rhamnolipid (RL)-enriched PA3 fraction derived from Pseudomonas aeruginosa SWUC02 in inducing systemic resistance in yellow chili seedlings and antifungal activity against C. truncatum CFPL01 (Col). Fractionation of the ethyl acetate extract yielded 12 fractions, with PA3 demonstrating the most effective disease suppression, reducing the disease severity index to 4 ± 7.35% at 7 days post-inoculation compared with Col inoculation alone (83 ± 23.57%). PA3 also exhibited direct antifungal activity, inhibiting Col mycelial growth by 41 ± 0.96% at 200 µg/mL. Subfractionation revealed PA3 as a mixture of mono- and di-RLs, confirmed by 1H nuclear magnetic resonance and electrospray ionization mass spectrometry data. Additionally, PA3 enhanced seed germination and promoted plant growth without causing phytotoxicity. Transcriptomics revealed that PA3 pre-treatment prior to Col infection primed the defense response, upregulating defense-related genes involved in the phenylpropanoid, flavonoid, and jasmonic acid biosynthesis pathways, as well as those associated with cell wall reinforcement. Our findings highlight the potential of RL-enriched PA3 as both an antifungal agent and a plant defense elicitor, with transcriptome data providing new insights into defense priming and resistance pathways in chili, offering an eco-friendly solution for sustainable anthracnose management.

Polymerization potential of a bacterial CotA-laccase for β-naphthol: enzyme structure and comprehensive polymer characterization.

Laccases are blue-multicopper containing enzymes that are known to play a role in the bioconversion of recalcitrant compounds. Their role in free radical polymerization of aromatic compounds for their valorization remains underexplored. In this study, we used a pBAD plasmid containing a previously characterized CotA laccase gene (abbreviated as Bli-Lacc) from Bacillus licheniformis strain ATCC 9945a to express this enzyme and explore its biotransformation/polymerization potential on β-naphthol. The protein was expressed from TOP10 cells of Escherichia coli after successful transformation of the plasmid. Immobilized metal affinity chromatography (IMAC) was used to generate pure protein. The biocatalytic polymerization reaction was optimized based on temperature, pH and starting enzyme concentration. 1H and 13C solution nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), and solid-state NMR (ssNMR) were used to characterize the formed polymer. A one-gram conversion reaction was done to explore applicability of the reaction in a pilot-scale. The polymerization reaction generated a brown precipitate, and its chemical structure was confirmed using 1H and 13C NMR and FTIR. SsNMR revealed the presence of two different orientational hydroxyl functional groups in the polymer in addition to the presence of a very small amount of ether linkages (< 2%). This analysis elucidated that polymerization occurred mainly on the carbons of the aromatic rings, rather than on the carbons attached to the hydroxyl groups, resulting in a condensed ring or polynuclear aromatic structure. The reaction was optimized, and the highest yield was attained under conditions of 37°C, pH 10 and a starting enzyme concentration of 440 nM in 50 mM phosphate buffer. A one-gram conversion yielded 216 mg of polymer as dry mass. The crystal structure of the enzyme was solved at 2.7 Å resolution using X-ray crystallography and presented with a hexagonal space group. The final structure was deposited in the Protein Databank (PDB) with an ID-9BD5. This article provides a green/enzymatic pathway for the remediation of phenolics and their valorization into potential useful polymeric materials. The comprehensive analysis of the formed polymer provides insight into its structure and functional moieties present. Based on the yield of the one-gram conversion, this synthetic method proves useful for a pilot-scale production level and opens opportunities to invest in using this polymer for industrial/environmental applications.

Highly Potent Fluorenone Azine-based ESIPT Active Fluorophores for Cellular Viscosity Detection and Bioimaging Applications.

Herein, synthesizes of fluorenone azine-based Schiff fluorescence probes: (E)-2-(((9H-fluoren-9-ylidene)hydrazineylidene)methyl)-5-(diethylamino)phenol (3a), (E)-9-(((9H-fluoren-9-ylidene)hydrazineylidene) methyl)-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-8-ol (3b), and (E)-1-(((9H-fluoren-9-ylidene)hydrazineylidene)methyl) naphthalen-2-ol (3c). The probes were structurally characterized using Fourier-transform infrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry(HRMS) analysis. The probes exhibit hydrogen bonding between phenolic -OH and imine nitrogen, enabling excited state intramolecular proton transfer (ESIPT) and free rotation in the azine (> C = N-N = C <) functional, facilitating twisted intramolecular charge transfer (TICT), and a positive solvatochromism in solvent-dependent emission studies. Further, density functional theory (DFT) based calculations accounted for the observed photophysical TICT and ESIPT processes, revealing a non-covalent interaction between phenolic -OH and imine nitrogen. Furthermore, the fluorescence intensity (log I) showed good linearity (R2 = 0.999) with the viscosity (log η) with Förster-Hoffmann coefficient (X) values of 2.238, 1.405 and 3.121 for 3a, 3b and 3c, respectively. The study established the probes toxicity and fluorescence imaging in the Caenorhabditis elegans model. Probe 3a, the first azine-based probe for micro viscosity detection, demonstrated exceptional efficacy in detecting intercellular viscosity and facilitating bioimaging applications.

Non-Targeted Metabolomics of White Rhinoceros Colostrum and Its Changes During Early Lactation by 1H Nuclear Magnetic Resonance Spectroscopy.

Dynamic changes in components from colostrum to mature milk occur in any mammal. However, the time it takes to reach the mature milk stage differs between taxa and species, as do the final concentrations of all the components. The white rhinoceros belongs to the family Perissodactyla, of which the milk and milk metabolome of the domesticated Equidae have been studied to some detail. Metabolomic information on the colostrum and milk of the Rhinocerotidae is lacking. Colostrum and milk were obtained from seven white rhinoceroses. Of note is that it was their first parturition and all followed the same diet, two factors known to affect colostrum composition and its changes during early lactation in domesticated mammals. Milk serum was prepared by the ultrafiltration of the milk samples. Untargeted 1N NMR spectra were processed with Topspin 3.2, calibration was carried out according to the alanine signal and the identification of signals was carried out with Chenomx and assignments in the literature. Statistical analysis of the data was carried out using MetaboAnalyst 6.0. The changes in the metabolites were followed during the first 7 days of lactation as well as on day 20. The amounts of amino acids and their derivatives, organic acids and lipid metabolites decreased over lactation, while carbohydrates and their derivatives increased. The colostrum phase ended on day 2, while the transition to mature milk seemed to be complete by day 7. From day 3 to 7, galactose metabolism and tyrosine metabolism were uprated. Of interest is the presence of the oligosaccharide 3'-sialyllactose on days 3 and 4 of lactation. Mainly the content of carbohydrates increased over lactation, specifically lactose. The 3'-sialyllactose content peaked on days 3 and 4 of lactation. The colostrum phase ended on day 2. The mature milk stage was reached by day 7. The galactose metabolism and tyrosine metabolism were uprated after day 3 of lactation.

Analysis of Poly(ethylene glycol) from the conservation of 17th century shipwreck Vasa and associated wooden objects

Vasa, a Swedish warship that sunk in 1628 and was excavated in 1961, and associated wooden objects underwent a preservation process using various low molecular weights (600, 1500, and 4000 Mn) of poly(ethylene glycol) (PEG) to gradually displace the water within the wooden structure, preventing the collapse of the waterlogged wood upon drying. However, after six decades of aging after application, to what extent are these polymers degraded? To investigate this, a Soxhlet apparatus was used to extract PEG from wooden samples of Vasa, and lyophilization was used to dry aqueous PEG solutions, these samples being the runoff accumulated during the application of different molecular weights of PEG to Vasa and other associated wooden objects. These samples underwent analysis via matrix-assisted laser desorption/ionization – time-of-flight mass spectrometry (MALDI-TOF MS), gel permeation chromatography (GPC), and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy.The primary discovery was that the PEG within Vasa exhibited minimal degradation, with the dominant identified species, as determined by MALDI-TOF MS and NMR spectroscopy, being HO-PEG-OH. However, small quantities of HO-PEG-OH had undergone degradation, resulting in the formation of PEG chains with distinct end groups, notably a range of carbonyl-based compounds, including aldehydes, carboxylic acids, and esters, as observed through MALDI-TOF MS, 1H, and 13C NMR spectroscopy. These mass spectrometry product peaks could be confirmed by the expected mass difference through various end-group functionalizations, such as oxidations, esterifications, or ether formations. In addition to the carbonyl-based degradation products, some PEG chains had completely cleaved into two separate lower molecular weight HO-PEG-OH polymers, each approximately half of their original molecular weight, as revealed by GPC analysis.

Synthesis, Biological Evaluation, and Molecular Docking Studies of Indole-Based Heterocyclic Scaffolds as Potential Antibacterial Agents.

Indole-based heterocyclic scaffolds have become increasingly important in medicinal chemistry due to their notable pharmacological and biological properties. Their role in the discovery and development of innovative drugs for treating various diseases highlights their value. This study aimed to synthesize C3-indole derivatives linked to various heterocyclic scaffolds, including thiophenes, thiazolidine-4-ones, and 1,3,4-thiadiazoles, via the reaction of ethylthioacetanilide 2 with different α-haloketones.The structures of the target compounds were established using 1H and 13C nuclear magnetic resonance spectroscopy, mass spectrometry, infrared spectroscopy, and elemental analysis. The synthesized compounds were tested for antimicrobial activity against different microbes: S. aureus ATCC 6538 (Gram-positive bacteria), E. coli ATCC 25933 (Gram-negative bacteria), C. albicans ATCC 10231 (yeast), and fungi (A. niger NRRL-A326). Thiophene 6a, thiazolidine-4-one 8, and compound 10d exhibited the highest antimicrobial activities. The molecular docking study showed that compounds 2, 4, 6a, and 6c had good binding energy and favorable binding modes of interactions with the DNA gyrase B enzymes (PDB: 3 U2D) and (PDB: 1S14). The results showed that the NH group of the indole in compounds 2 and 4, together with the nitrile group (CN), played an important role in inhibiting DNA gyrase B of S. aureus, PDB: 3 U2D. Furthermore, the NH of the indole ring, together with the ethylamino group of compound 2, was crucial in inhibiting DNA gyrase B of E. coli, PDB: 1S14. These findings may encourage researchers to develop more effective C3-indole derivatives in their search for antimicrobial drugs.

Nuclear Magnetic Resonance (NMR) and Density Functional Theory (DFT) Study of Water Clusters of Hydrogen-Rich Water (HRW)

The present study investigated the 1H Nuclear Magnetic Resonance (NMR) spectra of hydrogen-rich water (HRW) produced using the EVObooster device. The analyzed HRW has pH = 7.1 ± 0.11, oxidation–reduction potential (ORP) of (−450 ± 11) mV, and a dissolved hydrogen concentration of 1.2 ppm. The control sample was tap water filtered by patented technology. A 600 NMR spectrometer was used to measure NMR spectra. Isotropic 1H nuclear magnetic shielding constants of the most stable clusters (H2O)n with n from 3 to 28 have been calculated by employing the gauge-including-atomic-orbital (GIAO) method at the MPW1PW91/6-311+G(2d,p) density function level of theory (DFT). The HRW chemical shift is downfield (higher chemical shifts) due to increased hydrogen bonding. More extensive formations were formed in HRW than in control filtered tap water. The exchange of protons between water molecules is rapid in HRW, and the 1H NMR spectra are in fast exchange mode. Therefore, we averaged the calculated chemical shifts of the investigated water clusters. As the size of the clusters increases, the number of hydrogen bonds increases, which leads to an increase in the chemical shift. The dependence is an exponential saturation that occurs at about N = 10. The modeled clusters in HRW are structurally stabilized, suggesting well-ordered hydrogen bonds. In the article, different processes are described for the transport of water molecules and clusters. These processes are with aquaporins, fusion pores, gap-junction channels, and WAT FOUR model. The exponential trend of saturation shows the dynamics of water molecules in clusters. In our research, the chemical shift of 4.257 ppm indicates stable water clusters of 4–5 water molecules. The pentagonal rings in dodecahedron cage H3O+(H2O)20 allow for an optimal arrangement of hydrogen bonds that minimizes the potential energy.

CBMAFF-Net: An Intelligent NMR-Based Nontargeted Screening Method for New Psychoactive Substances.

With the proliferation and rapid evolution of new psychoactive substances (NPSs), traditional database-based search methods face increasing challenges in identifying NPS seizures with complex compositions, thereby complicating their regulation and early warning. To address this issue, CBMAFF-Net (CNN BiLSTM Multistep Attentional Feature Fusion Network) is proposed as an intelligent screening method to rapidly classify unknown confiscated substances using 13C nuclear magnetic resonance (NMR) and 1H NMR data. Initially, we utilize the synergy of a convolutional neural network (CNN) and bidirectional long short-term memory network (BiLSTM) to extract the global and local features of the NMR data. These features are sequentially fused through a weighted approach guided by an attention mechanism, thoroughly capturing the essential NPS information. We evaluated the model on a generated simulated data set, where it performed with 99.8% accuracy and a 99.8% F1 score. Additionally, testing on 42 actual seizure cases yielded a recognition accuracy of 97.6%, significantly surpassing the performance of conventional database-based similarity search algorithms. These findings suggest that the proposed method holds substantial promise for the rapid screening and classification of NPSs.

Longitudinal 1H NMR-Based Metabolomics in Saliva Unveils Signatures of Transition from Acute to Post-Acute Phase of SARS-CoV-2 Infection.

COVID-19 can range from a mild to severe acute respiratory syndrome and also could result in multisystemic damage. Additionally, many people develop post-acute symptoms associated with immune and metabolic disturbances in response to viral infection, requiring longitudinal and multisystem studies to understand the complexity of COVID-19 pathophysiology. Here, we conducted a 1H Nuclear Magnetic Resonance metabolomics in saliva of symptomatic subjects presenting mild and moderate respiratory symptoms to investigate prospective changes in the metabolism induced after acute-phase SARS-CoV-2 infection. Saliva from 119 donors presenting non-COVID and COVID-19 respiratory symptoms were evaluated in the acute phase (T1) and the post-acute phase (T2). We found two clusters of metabolite fluctuation in the COVID-19 group. Cluster 1, metabolites such as glucose, (CH3)3 choline-related metabolites, 2-hydroxybutyrate, BCAA, and taurine increased in T2 relative to T1, and in cluster 2, acetate, creatine/creatinine, phenylalanine, histidine, and lysine decreased in T2 relative to T1. Metabolic fluctuations in the COVID-19 group were associated with overweight/obesity, vaccination status, higher viral load, and viral clearance of the respiratory tract. Our data unveil metabolic signatures associated with the transition to the post-acute phase of SARS-CoV-2 infection that may reflect tissue damage, inflammatory process, and activation of tissue repair cascade. Thus, they contribute to describing alterations in host metabolism that may be associated with prolonged symptoms of COVID-19.

Identification of Biochemical Determinants for Diagnosis and Prediction of Severity in 5q Spinal Muscular Atrophy Using 1H-Nuclear Magnetic Resonance Metabolic Profiling in Patient-Derived Biofluids.

This study explores the potential of 1H-NMR spectroscopy-based metabolic profiling in various biofluids as a diagnostic and predictive modality to assess disease severity in individuals with 5q spinal muscular atrophy. A total of 213 biosamples (urine, plasma, and CSF) from 153 treatment-naïve patients with SMA across five German centers were analyzed using 1H-NMR spectroscopy. Prediction models were developed using machine learning algorithms which enabled the patients with SMA to be grouped according to disease severity. A quantitative enrichment analysis was employed to identify metabolic pathways associated with disease progression. The results demonstrate high sensitivity (84-91%) and specificity (91-94%) in distinguishing treatment-naïve patients with SMA from controls across all biofluids. The urinary and plasma profiles differentiated between early-onset (type I) and later-onset (type II/III) SMA with over 80% accuracy. Key metabolic differences involved alterations in energy and amino acid metabolism. This study suggests that 1H-NMR spectroscopy based metabolic profiling may be a promising, non-invasive tool to identify patients with SMA and for severity stratification, potentially complementing current diagnostic and prognostic strategies in SMA management.

Synthesis of Amorphous Cellulose Derivatives via Michael Addition to Hydroxyalkyl Acrylates for Thermoplastic Film Applications.

The aim of this study is to prepare new cellulose derivatives that show good feasibility and processability. Accordingly, in this study, we demonstrate Michael addition to hydroxyalkyl acrylates, that is, 2-hydroxyethyl and 4-hydroxybutyl acrylates (HEA and HBA, respectively), to synthesize amorphous cellulose derivatives under alkaline conditions. The reactions were carried out in the presence of LiOH in ionic liquid (1-butyl-2,3-dimethylimidazolium chloride)/N,N-dimethylformamide (DMF) solvents at room temperature or 50 °C for 1 h. The Fourier transform infrared and 1H nuclear magnetic resonance (NMR) measurements of the products supported the progress of Michael addition; however, the degrees of substitution (DS) were not high (0.3-0.6 for HEA and 0.6 for HBA). The powder X-ray diffraction analysis of the products indicated their amorphous nature. The cellulosic Michael adduct from HEA with DS = 0.6 was swollen with high polar organic liquids, such as DMF. In addition to swelling with these liquids, the cellulosic Michael adduct from HBA was soluble in dimethyl sulfoxide (DMSO), leading to its 1H NMR analysis in DMSO-d6. This adduct was found to form a cast film with flexible properties from its DMSO solutions. Furthermore, films containing an ionic liquid, 1-butyl-3-methylimidazolium chloride, showed thermoplasticity. The Michael addition approach to hydroxyalkyl acrylates is quite effective to totally reduce crystallinity, leading to good feasibility and processability in cellulosic materials, even with low DS. In addition, the present thermoplastic films will be applied in practical, bio-based, and eco-friendly fields.