NMR Analysis Research Articles

Synthesis, X-ray, Hirshfeld Surface Analysis, Computational investigations, ADME investigations, and Insecticidal Activities using Docking Simulation of Kite-like 2,4,6-triarylpyridine

In this study, we synthesized the new 2,4,6-triaryl pyridine by reacting alkoxy chalcone with ammonium acetate, followed by extensive characterization utilizing a variety of spectral techniques such as FT-IR, NMR, Mass, and X-ray analysis. In addition, a comparison was made between the compound's X-ray structure and its optimized molecular structure based on bond lengths and angles. Furthermore, theoretical investigations were conducted to elucidate the physical properties of both the starting compounds and the produced compound and to study their electrochemical behavior to understand their oxidation and reduction processes. The ADME analysis showed the insolubility of these compounds and directed us to use them in insecticidal activities on two insect species, Plodia interpunctella, and Nilaparvata lugens. The results showed efficacy comparable to the Thiamethoxam drug and these biological results were confirmed with molecular docking simulation on different proteins.

Design, synthesis, characterization, and biological activities of novel Ag(I)-NHC complexes based on 1,3-dioxane ligand

Herein, a series of new Ag(I)-NHC complexes containing 1,3-dioxane group were synthesized by the direct reaction of Ag2O and benzimidazolium salts in light-free conditions. All Ag(I)-NHC complexes were spectrally characterized using 1H, 13C NMR, FT-IR, LC-MS, and elemental analysis. Additionally, the structures of compounds 1a and 1e were elucidated by the single X-ray diffraction techniques. Further, the synthesized Ag(I)-NHC complexes were evaluated for cytotoxicity study on the L-929 cells and the anticancer activity against the HCT 116 and MCF-7 cancer cell lines. Notably, 1a showed significant anticancer activity against HCT 116 with an IC50 of 6.37 ± 0.92 μg/mL compared to cisplatin (IC50 = 36.75 ± 1.76 μg/mL). 1c (IC50 = 3.21 ± 1.96 μg/mL) and 1e (IC50 = 3.72 ± 1.12 μg/mL) exhibited significant anticancer activity against MCF-7 cells and was similar to cisplatin (IC50 = 32.17 ± 2.85 μg/mL). Meanwhile, 1a and 1e displayed the highest selectivity index. Most importantly, the cell viability test showed that 1e induced neglectable cytotoxicity (IC50 = 36.38 ± 2.27 μg/mL) toward L-929 and was similar to cisplatin (IC50 = 36.11 ± 2.09 μg/mL). The anticancer activities of Ag(I)-NHC complexes vary depending on the substituent group of the silver complex and the cell line type. Moreover, the inhibitory mechanism of 1e was not dependent on caspase-associated apoptosis initiated by the lysosomal-mitochondrial pathway. Taken together, we conclude that this work provides a simple and rapid protocol for the synthesis of Ag(I)-NHC complexes and the featured Ag(I)-NHC complexes have an anticancer drug potential for biomedical applications.

Ultrasonic-assisted synthesis for the production of green and sustainable hemp carboxymethyl cellulose

Hemp fiber (Cannabis sativa) is being widely used to produce carboxymethyl cellulose (CMC). This study focused on synthesizing carboxymethyl cellulose from bleached hemp fiber to investigate the impact of different factors, i.e., chemical concentration and synthesis time, on its characteristics. The fiber morphology analysis revealed desirable properties, which are essential for high-quality CMC production. Optimal condition for CMC synthesis were investigated, which involved using 20 % NaOH (w/v), the shortest total synthesis time (2.30h), and using 0.9 g MCA (w/w). This resulted in a non-significantly high DS (0.80) in both nonspray-dried and spray-dried hemp carboxymethyl cellulose, representing a high CMC content around 96 %. Moreover, the use of ultrasonic assistance and spray drying techniques significantly improved the hemp carboxymethyl cellulose properties, indicating a decreased molecular weight (2.65 × 104 g/mol) and a decreased particle size (7.82 μm). Thermal analysis revealed that spray-dried hemp carboxymethyl cellulose had lower thermal stability than hemp fiber and nonspray-dried hemp carboxymethyl cellulose. FTIR and 13C NMR analyses confirmed the successful CMC synthesis. Additionally, XRD and SEM analyses demonstrated changes in the crystalline structure and hemp carboxymethyl cellulose surface morphology. This revealed advanced techniques that could enhance hemp carboxymethyl cellulose quality and properties, making it suitable for various industrial applications.

Enhancing solution structural analysis of large molecular proteins through optimal stereo array isotope labeling of aromatic amino acids

The observation of side-chain peaks of aromatic amino acids is the prerequisite for a high-resolution three-dimensional structure determination of proteins by NMR. However, it becomes difficult with increasing molecular size due to an increased transverse relaxation and the control of the relaxation pathway is needed to achieve the observation. We demonstrated that even for the large molecular size of 82 kDa Malate synthase G (MSG), the aromatic 13C1H (CH) peaks of Tryptophan (Trp) and Phenylalanine (Phe) residues can be observed with high quality using a systematic stable isotope labeling scheme, Stereo-Array Isotope Labeling (SAIL) method. However, the sequence specific assignments of these peaks relied on the use of amino acid substitutions, employing an inefficient method that required many isotopes labeled samples. In this study, we developed novel SAIL amino acids that allow for the observation of the aromatic ring δ,ζ and the aliphatic β position peak of Phe residues. The application of TROSY-based experiment to the isolated CH moieties resulted in the successful observation of discernible and resolved CH peaks in Phe residues in MSG. In MSG, the sequence-specific assignments of the backbone and Cβ positions have already been confirmed. Therefore, using this labeling method, the δ and β position peaks of Phe residues can be clearly assigned in a sequence-specific and stereospecific manner through experiments based on intra-residue NOE. Furthermore, the NOESY experiment also allows for the acquisition of information pertaining to the conformation of Phe residues, such as the χ1 dihedral angle, providing valuable insights for the determination of accurate protein structures and in dynamic analysis. This new SAIL amino acids open an avenue to achieve a variety of NMR analysis of large molecular proteins, including a high-resolution structure determination and dynamics and interaction analysis.

Development of a binarization analysis technique and characteristic for mixed-matrix pervaporation membranes

Pervaporation (PV) is considered a promising energy-efficient process for recovering ethanol from fermentation liquids. In this study, ethanol separation characteristics were elucidated using mixed-matrix pervaporation membranes composed of hydrophobic polymers (PDMS) and high-silica ZSM-5 (HSZ). The selectivity and flux of ethanol/water were both improved when HSZ content in PDMS matrices was increased — at 50 wt% HSZ content the selectivity reached 15 and the flux of ethanol was improved to 0.05 kg/m2/hr. A new method was demonstrated to quantify the local thickness of the PDMS matrices by cross-sectional SEM binarization and inscribed circle analysis. PDMS matrices became more uniform with an increase in the HSZ content. The uniform presence of the PDMS matrices can be interpreted as more uniform dispersion of HSZ particles. An increase in total length of PDMS-HSZ interface resulted in improved ethanol permeability. NMR analysis showed that the molecular mobility of PDMS was restricted. Those results suggest an increase in the physical interaction between PDMS and HSZ. This study demonstrated a new analytical method for understanding the local thickness of the PDMS matrices and the interfacial state of mixed-matrix pervaporation membranes.

Synthesis, Antimicrobial activity and Computational studies on (E)-N-(2((4-chlorobenzylidine)amino)ethyl)napthalen-1-amine

The novel Schiff bases were synthesized by combining N1-(Napthalen-1-yl)ethane 1,2-diamine with chlorine-substituted benzaldehyde. The compound is designated as (E)-N-(2((4-chlorobenzylidine)amino)ethyl)napthalen-1-amine (4CLB). This structure was verified by experimental techniques including infrared, NMR, fluorescence, UV, and theoretical methods. Using the B3LYP functional the titled compound computational study was executed. The results for infrared and NMR analysis of the molecule exhibited a significant degree of agreement in both observed and simulated. The reactivity characteristics of 4CLB were computed. The microbiological efficacy of the compound was assessed against multiple Gram-positive bacteria S. aureus, S pneumonia, and Bacillus subtilis. The compound was tested against the following Gram-negative bacteria: Klebsiella pneumonia, E coli, and Proteus vulgaris. The compound Schiff base exhibits the most effective antibacterial activity against all microbes. The 4CLB compound quantum calculations have a strong correlation with antibacterial activity. The compound has non-covalent Hydrogens, these Hydrogens are bonded with the corresponding proteins. It is checked by molecular docking in the Auto Dock software.

Preparation and structural characterization of a sulfated octasaccharide with heparin-like anticoagulant activity

Heparins are sulfated polysaccharides with a heterogeneous mixture derived from animal tissues, subject to supply limitations and the risk of animal virus residues. Patients using heparin also face the risks of spontaneous bleeding and thrombocytopenia. Here we reported an efficient riclinoctaose-based approach for rapid chemical synthesis of a structurally defined heparin-like anticoagulant sulfated octasaccharide (SRO). We used sulfur trioxide-pyridine, sulfur trioxide-trimethylamine, and sulfur trioxide-triethylamine complexes as solvents for one-pot O-sulfation and determined the optimal conditions for synthesizing SRO. Sulfur trioxide-trimethylamine provided reasonable control over the degree of substitution between 1.85 and 1.88, revealing a single molecule with a theoretical molecular weight of 2952.96 g/mol. The structural features of the SRO were carried out by Fourier transform infrared spectroscopy and one- and two- dimensional 1H and 13C NMR analysis, revealing sulfation repeatedly present at the fixed positions of C-6/C-2/C-3 and reducing terminals. The anticoagulant activity of SRO was demonstrated by efficiently blocking coagulation in the blood of mice and human. SRO dose-dependently decreased ferric chloride-induced experimental thrombosis in mice. Like heparin, SRO specifically inhibits coagulation factor Xa, but significantly reduces the risk of bleeding compared to heparin. Therefore, we named it octaparin. These results support that octaparin is expected to replace animal-sourced heparin.

Substituent Effect in Salicylaldehyde 2-Furoic Acid Hydrazones: Theoretical and Experimental Insights into DNA/BSA Affinity Modulation, Antimicrobial and Antioxidant Activity

The biological properties of five aroylhydrazones derived from salicylaldehyde and its 5-substituted derivatives with 2-furoic acid hydrazide were thoroughly investigated. NMR analysis confirmed the predominant existence of the aroylhydrazones in the keto-amine form in aqueous solution. Geometries of these compounds were optimized using density functional theory (DFT) calculations with the B3LYP hybrid functional, while ADMET analysis predicted their pharmacokinetic and toxicological properties. Substituent effects on the interactions between the salicyl aroylhydrazones and BSA and DNA were elucidated through experimental and molecular docking studies, revealing the bromo-substituted hydrazone as the most potent binder to both biomolecular targets. Experimental results aligned well with theoretical predictions, indicating that salicyl hydrazones predominantly act as DNA groove binders. Thermodynamic analysis suggested that the hydrazones predominantly interact with BSA through hydrogen bonding and van der Waals forces. Moreover, antioxidant potential assessment using DPPH, ABTS, FRAP, and metal chelating assays demonstrated the potent antioxidant power of nitro and hydroxy-substituted derivatives. Additionally, the antimicrobial properties of hydrazone against Gram-positive and Gram-negative bacteria, as well as fungi, were thoroughly explored, highlighting the nitro derivative as the most prominent candidate with broad-spectrum antimicrobial potential.

Sulfated polysaccharide from Apostichopus japonicus viscera exhibits anti-inflammatory properties in vitro and in vivo

Polysaccharides from sea cucumbers are known for their biological activities, but little is known about those from sea cucumber viscera. The present study isolated a sulfated polysaccharide (SCVP-2) from the viscera of Apostichopus japonicas, which had a molecular weight of 209.1 kDa. SCVP-2 comprised 66.3 % total sugars, 2.1 % uronic acid, 4.5 % proteins, and 25.5 % sulfate groups, containing glucosamine, galactosamine, glucose, galactose, and fucose. FT-IR and NMR analyses identified SCVP-2 as a fucoidan sulfate with sulfation patterns of the fucose branches as Fuc2S, Fuc4S, and Fuc0S. SEM and AFM analyses showed irregular clusters and linear conformations. SCVP-2 demonstrated strong anti-inflammatory properties both in vitro and in vivo. In lipopolysaccharide (LPS)-induced inflammation in macrophage RAW264.7 cells, SCVP-2 significantly reduced nitric oxide (NO) and cytokine secretion (IL-1β, IL-6, TNF-α). Additionally, it downregulated the expression of these cytokine genes. Furthermore, the anti-inflammatory mechanism of SCVP-2 was related to the inhibition of the MAPKs and NF-κB pathways. SCVP-2's anti-inflammatory capacity was confirmed in acute inflammation models, including xylene-induced ear swelling and acetic acid-induced peritoneal capillary permeability, and in high-fat diet-induced systemic low-grade chronic inflammation. In conclusion, SCVP-2 exhibits significant anti-inflammatory activity, suggesting its potential for development as a functional food ingredient or therapeutic agent for inflammation-related diseases.

Influence of banana peel waste biomass ratio in Co-pyrolysis of waste plastics to regulate aromatic content and oxygenated compounds: A study of liquid product characterization and its CI engine performance

We have reported the importance of biomass ratio in the co-pyrolysis of waste plastics to regulate the aromatic content and oxygenated compounds in hydrocarbon-rich fuels for enhancing engine performance. The study revealed that changing biomass to plastic ratio can control aromatic compositional change. The obtained product was characterized using different instrumentation techniques, such as NMR, FTIR, GCMS, etc., to identify the hydrocarbon types in the liquid product. Results revealed that it contains C8-C24 range carbon compounds with dominating aromatics compounds, as confirmed by 1H NMR and FTIR analysis. The pyro-oils contain different hydrocarbons: olefins, paraffin, aromatics, esters, and alcohols. It was observed that the presence of biomass in co-pyrolysis produces oxygenated compounds up to ∼12.08 % and also enhances calorific value up to 55.4 MJ/kg from 48.3 MJ/kg due to the presence of longer hydrocarbon chains of esters in pyro-oil. Biomass co-pyrolysis also improved the fuel properties such as pour point (<-25°C) and 4°C increment in flash point. Engine performance showed that blending biomass pyro-oil obtained from B25PS75 reduced fuel consumption and increased BTE.

Synthesis and characterization of modified chitosan as a promising material for enterosorption of heavy metal ions

Currently, an important ecological problem is environmental pollution and its negative impact on living organisms, the consequences of which are deterioration in general health and the manifestation of various diseases, poisoning, endo- and exotoxicosis. Enterosorption method was proposed as a promising method for removing toxic substances from the living organisms using enterosorbents which can absorb various toxic substances of endogenous and exogenous nature in the lumen of the gastrointestinal tract. It has been proposed to use polymer-containing enterosorbents for eliminating of heavy metals from the organism. The purpose of this research was to synthesize a quaternized derivative of chitosan, specifically N-(2-hydroxybenzyl)-N-ethyl-N-methyl chitosan chloride (Q-CHS). The synthesis of Q-CHS involved the formation of a Schiff base, followed by the quaternization of the amino group of chitosan (CHS). The structures of both pure CHS and quaternized CHS were studied using various physico-chemical methods, including FTIR, NMR, XRD, SEM, DSC and TGA analyses in order to determine the structure and confirm the formation of the final product.

The Synergistic Effect of Water Reducer and Water-Repellent Admixture on the Properties of Cement-Based Material

Water reducer and water-repellent admixture are very important in improving the workability and durability of cement-based materials. However, the synergistic effect of the two types of admixtures has not been well investigated. In this study, polycarboxylate ether-based superplasticizer (PCE) and octyltriethoxysilane (OTS) were adopted as water reducer and water-repellent admixture, respectively. Their synergistic effect on the fluidity, compressive strength, and water absorption rate of cement-based materials was investigated. Particularly, the pore structure and hydration state of cement paste were analyzed using 1H Low-Field Nuclear Magnetic Resonance (1H LF NMR). The result showed that the fluidity of cement paste containing different dosages of PCE was reduced by 5–10 mm by incorporating 1% OTS, and the compressive strength at the early age of 3 d of mortar containing high PCE dosage of 0.25% decreased up to 15% by using 1% OTS. In contrast, the compressive strength of mortar containing 0.20% PCE was slightly enhanced by the addition of 1% OTS. 1H LF NMR analysis revealed that the combination of PCE and OTS would increase the pore size and total pore volume of cement paste, and more bleeding water would be generated at high PCE dosage. The intensity-weighted T2 values of the main peak (T2¯) implied that both PCE and OTS produced a retardation effect on cement hydration. However, the water absorption rate decreased by 46.6% despite the increase in pore size and total pore volume. The conflict phenomenon powerfully revealed that the internal hydrophobic treatment by OTS has been successfully achieved. Overall, the combination of 0.20% PCE and 1% OTS exerted a positive synergistic effect in improving the compressive strength and water-repelling ability of cement-based materials, which is meaningful for improving their durability and service life.

Fungal Coculture of Herpotrichia sp. and Trametes versicolor Induces Production of Diverse Metabolites with Anti-Parkinson's Neuroprotective Activity.

Co-cultivation of isopod-associated fungi Herpotrichia sp. SF09 and Trametes versicolor SF09A led to the reciprocal induction of thirteen new compounds (1-7 and 9-13) with diverse architectures. Importantly, compounds 1 and 2 are rare fungal sesquiterpene-saccharide hybrids incorporating a xylopyranose moiety, compound (±)-3 represents the first example of a natural linear sesquiterpene racemate, and compound 7 is a rare α-pyrone derivative with a xylopyranose motif. Their structures were elucidated by analysis of NMR and mass spectrometry data, and their absolute configurations were determined by Mosher's method, microscale derivatization, and single-crystal X-ray diffraction, as well as ECD calculations. All the isolated compounds ameliorated MPP+-induced oxidative damage in PC12 cells in a dose-dependent fashion. Among them, compounds 5 and 15 showed significant protective action against neuronal injury by MPP+ at 5 μM. Meanwhile, transcriptome sequencing was performed to evaluate the molecular mechanism of the neuroprotective activity for compound 5. Results indicated that compound 5 might mitigate MPP+-induced neuronal injury through the regulation of multiple signaling pathways, including the PI3K-Akt and MAPK pathways. Our findings suggested that compound 5 could be a promising neuroprotective agent for the treatment of Parkinson's disease.

The role of carboxylic acid contents in calcium-based metal-organic frameworks for the enhancement of Biginelli reaction

Metal-organic frameworks (MOFs) can carry different functional groups such as COOH, NH2, and SO3H. The most commonly used functional group was COOH due to its Brønsted acidity, polarity, and ability to bond with organic compounds and metals through various interactions. Here, calcium-based MOFs (Ca-MOFs) with different carboxylic arms were successfully prepared and used in heterogeneous Biginelli catalytic reactions. The prepared materials (Ca-BDC-H, Ca-BDC-COOH, and Ca-BDC-(COOH)2) were characterized using different spectroscopic techniques and the morphological structures were determined using microscopic analysis. Besides elucidating the fine form of MOFs, the role of the carboxylic content was tested in multicomponent reaction catalysis in different kinetics and thermodynamic studies, the formation of catalytic products was determined using NMR analysis, and the proposed mechanism was investigated. The results obtained showed that as the carboxylic content in the network increases, the catalytic reaction yield increases which can support the possibility of using the COOH group present in the network with acidic properties in heterogeneous catalysts giving high product yield.

Alumina-supported multi-metal catalyst for e-waste management for reclamation of valuable products

ABSTRACT Electronic and electrical waste (e-waste) has increased exponentially due to the humungous growth in the information technology and communication sector. Many multi-metal catalysts are developed by researchers for electronic waste plastic conversion into fuel products and recovery of valuable metals. In the present study, an Alumina-supported catalyst powder with selected transition metals metal oxides was prepared to improve the yield of hydrocarbon liquids. FESEM with energy-dispersive spectroscopy, XRD and laser diffraction particle size analysis were used to characterise catalysts. The shredded e-waste chips to catalyst weight ratio was maintained from 2:1 to 10:1 and studied. The experiments were conducted with a reaction temperature range from 300°C to 500°C. The produced fuel density was 0.88 kg/L, with 0.75 liquid fuel conversion and 71.7% overall liquid fuel yield. The light gas percentage was 4–6%. NMR analysis, bomb calorimetric study and gas chromatography-mass spectroscopy of liquid fuel analysis suggest carbon chain compounds of C3–C20 hydrocarbon, indicating a mixture of petrol and diesel-like liquid products. The catalyst can be tuned to improve liquid fuel conversion. The liquid fuel product is promising for fuel use, however, upgrading treatments are needed to meet standard product specifications.

Plasma and radiation mediated green synthesis of gold Nanoparticles-immobilized bio-template based catalytic reactor ‘AuNICaR’: Mechanistic insights, catalytic performance and reusability analysis

The present work reports a green, non-thermal plasma-based approach for efficient synthesis of a gold nanoparticles (Au NPs) Immobilized Catalytic Reactor “AuNICaR” via a novel, efficient, indigenously developed process termed “Plasma Assisted Synthesis and Simultaneous Immobilization (PASSI)”, using isopropanol to enhance the reducing plasma environment. Au NPs were synthesized and simultaneously immobilized onto a cellulose based bio-template pre-functionalized via radiation induced grafting of 2,3-epoxypropylmethacrylate (EPMA) onto a nonwoven cellulose (NWC) substrate. The process entails minimal wastage of expensive gold precursor and eliminates use of external chemicals (reducing and stabilizing agents). Samples were characterized by 13C NMR, FTIR, XPS, TGA, DSC, SEM-EDS, BET, and EDXRF analysis. Catalytic activity was assessed by spectrophotometrically monitoring the reduction of p-nitroaniline (PNA) in presence of NaBH4. DFT calculations established the interaction between Au NPs and EPMA groups of the bio-template to be occurring in ratios of 1:1 and 1:2, with 1:1 being more stable. ANN modelling was also invoked to investigate the effect of simultaneous variation of plasma process parameters on the catalytic performance. AuNICaR was demonstrated for catalytic reduction of pollutants: PNA, p-nitrophenol (PNP) and methyl orange (MO) azo dye in both batch and continuous flow mode. Over 25000 mL of cumulative pollutant feed with concentrations ranging from 0.06 mM − 2 mM was treated at a flow rate of 540 mL.h−1, using a single catalyst batch after intermittent washing with water. With excellent storage stability of > 12 months and > 92 % retention in catalytic activity post multiple cycles, AuNICaR certifies as a potentially inexhaustible catalytic system for cost-effective pollutant treatment.

Oil palm frond leaves (OPFLs), a high recalcitrant biomass as an alternative cellulose source for glucose conversion

Among the oil palm biomass, oil palm frond leaves (OPFLs) are under-valued since they can be classified as a high recalcitrance feedstock due to the high lignin and hemicellulose content. This work proposes a new way of using OPFLs as alternative cellulose sources for glucose conversion by an application of various pre-treatments at varying parameters. From green pre-treatment, steam explosion (SE) is much more effective in disrupting the OPFLs structure in contrast to hydrothermal (HT) pre-treatment, by a vast dissolution of hemicellulose and depolymerization of lignin. The pre-impregnation with H2SO4 prior to steam explosion was beneficial to enhance the hemicellulose removal up to 89.94 %. The 2D-HSQC NMR analysis divulged the reduction of ß-O-4 linkage and S/G value after the SE and HT pre-treatment, verifying the degradation of lignin-carbohydrate linkage in OPFLs. Meanwhile, the dilute NaOH pre-treatment enhanced the delignification by 87.14 %. SEM analysis revealed a well-disrupted structure of pre-treated OPFLs exposing a higher cellulosic fraction, whereas SEC analysis divulged a decreasing pattern of degree of polymerization of cellulose. The enzymatic analysis revealed that pre-treated OPFLs yielded higher glucose ranging from 29.81 % to 49.98 % w/w, which was ∼3-fold higher than raw OPFLs (14.31 % w/w). A maximum cellulose digestibility (100 %) was achieved by steam-exploded OPFLs after 72 h of enzymatic hydrolysis. This suggests the potency of various pre-treatments to enhance enzymatic saccharification of OPFLs producing a higher glucose yield.

Late-stage Fluorination of Tyrosine Residues in Antiviral Protein Cyanovirin-N.

The applications of fluorinated molecules in chemical biology are rapidly expanding driven by the unique properties of C-F bonds, leading to increased interest in methodologies for controlled introduction of this atom. In this study, we present the first method for late-stage fluorination of tyrosine residues in proteins. Our results demonstrate that electrophilic fluorination using Selectfluor, a stable and non-toxic reagent, offers a straightforward and cost-effective method for labeling Cyanovirin-N (CVN), a 101-amino-acid lectin with effective antiviral activity. Uni- and bidimensional 1H, 13C and 19F NMR analyses, along with mass spectrometry, revealed chemoselective fluorination of the three tyrosine residues in CVN without affecting its overall structure or mannose-binding affinity. Additionally, we observed that other aromatic amino acids, such as tryptophan, phenylalanine, and histidine, are not fluorinated using this method. These findings advance our understanding of protein fluorination and its applications in studying structure, dynamics, and interactions, as well as other biological utilities.

Xanthated cellulose nanofibers dispersion: Stability, pickering emulsion with styrene, and latex composite via polymerization

Leveraging xanthated cellulose nanofibers (XCNF) from a modified rayon process, this study explores their use as stabilizers in Pickering emulsion polymerization for nanocomposite production. XCNF was produced from softwood pulp through a xanthation process that utilized a reduced NaOH concentration of 8.5 %, lower than the typical rayon process, and was followed by mechanical defibrillation, resulting in fiber widths under 10 nm. Following the protective allylation of xanthate groups and hydrophobic modification, 1H NMR analysis was conducted, revealing a xanthation degree of 0.144. When stored at 4 °C, a 0.5 wt% XCNF dispersion gelled by the fifth day, as confirmed by visual and rheological assessments. UV and TEM analyses indicated xanthate detachment and nanofiber aggregation over time, respectively. The addition of a low-temperature initiator to the XCNF-stabilized styrene-water emulsion enabled polymerization, yielding nanofiber-encapsulated polystyrene latex. This led to transparent sheets upon thermal pressing, demonstrating the potential of XCNF in developing polymer nanocomposites.

Green extraction of marine phospholipids from Conger eel by-product using SC-CO2: Lipidomic profiles and biological activities

This paper presents an eco-friendly approach to recovering phospholipids (PLs) from the Conger myriaster head (CMH) via supercritical carbon dioxide (SC–CO2) extraction using ethanol as a cosolvent. The lipidomic profile and biological activities of the extracted PLs were investigated. Purity assessments, PL composition analysis, and fatty acid profiling were performed to characterize the PLs. Biological activity was determined through antioxidant, antimicrobial, antihypertensive, anti-inflammatory, and anticancer evaluations. The results showed that the yields of the SC–CO2 extracted CMH PLs (SCHP) and organic solvent extracted CMH PLs (OCHP) were 3.26% ± 0.20 % (76.18% ± 0.09% purity) and 9.02% ± 0.21% (purity = 18.29% ± 0.04%), respectively. The 31P NMR analysis revealed a diverse PL composition in both extracts, with the SCHP showing higher PC content and selective extraction characteristics. The SCHP exhibited significantly superior antioxidant, antimicrobial, antihypertensive, and anti-dementia activities compared to the OCHP. Both extracts inhibited nitric oxide production in RAW 264.7 cells, suggesting anti-inflammatory activity. Selective anticancer activity was observed, with high toxicity in SK-N-SH cells but no cytotoxicity in RAW 264.7 and HaCaT cells. The findings highlight the potential of SC-CO2 extraction using ethanol to obtain bioactive PLs from marine by-products, with promising applications in the pharmaceutical, cosmetic, and food industries.