Proton Nuclear Magnetic Resonance Research Articles

Uracil as a biomarker for spatial pyrimidine metabolism in the development of gingivobuccal oral squamous cell carcinoma

AbstractNo biomarker has yet been identified that allows accurate diagnosis and prognosis of oral cancers. In this study, we investigated the presence of key metabolites in oral cancer using proton nuclear magnetic resonance (NMR) spectroscopy to identify metabolic biomarkers of gingivobuccal oral squamous cell carcinoma (GB-OSCC). NMR spectroscopy revealed that uracil was expressed in 83.09% of tumor tissues and pyrimidine metabolism was active in GB-OSCC; these results correlated well with immunohistochemistry (IHC) and RNA sequencing data. Based on further gene and protein analyses, we proposed a pathway for the production of uracil in GB-OSCC tissues. Uridinetriphosphate (UTP) is hydrolyzed to uridine diphosphate (UDP) by CD39 in the tumor microenvironment (TME). We hypothesized that UDP enters the cell with the help of the UDP-specific P2Y6 receptor for further processing by ENTPD4/5 to produce uracil. As the ATP reserves diminish, the weakened immune cells in the TME utilize pyrimidine metabolism as fuel for antitumor activity, and the same mechanism is hijacked by the tumor cells to promote their survival. Correspondingly, the differential expression of ENTPD4 and ENTPD5 in immune and tumor cells, respectively, indicatedtheir involvement in disease progression. Furthermore, higher uracil levels were detected in patients with lymph node metastasis, indicating that metastatic potential is increased in the presence of uracil. The presence of uracil and/or expression patterns of intermediate molecules in purine and pyrimidine pathways, such asCD39, CD73, and P2Y6 receptors together with ENTPD4 and ENTPD5, hold promise as biomarker(s) for oral cancer diagnosis and prognosis.

Effect of Oligoricinoleic Acid on Degradation of Polylactic Acid

ABSTRACT The objective of this research is to explore the impact of oligoricinoleic acid (ORA) on the degradation of polylactic acid (PLA). ORA was synthesized from ricinoleic acid using tin (II) 2-ethylhexanoate as a catalyst. The chemical structures of the obtained ORA were confirmed by Fourier-transform infrared spectrometer (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H-NMR). PLA/ORA films were prepared through the casting method by varying ORA concentrations as 0.1%wt, 0.3%wt, 0.5%wt, 1.0 wt%, and 3.0%wt. Degradation of the films via hydrolysis was studied by soaking the films in deionized water and stirring at 120 rpm in an incubator at 37°C. Alterations in the structure and properties of the films were investigated after soaking for 7, 14, 21, and 28 days using ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectrometer (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), and universal testing machine (UTM). Gel permeation chromatography (GPC) was performed to confirm the decrease in molecular weight (MW). The presence of 3%wt ORA could promote both ductility and degradation of PLA films. ORA further enhances thermal stability, indicating potential for prevention of thermal degradation during melt processing.

A drug–drug cocrystal strategy to regulate stability and solubility: A case study of temozolomide/caffeic acid

Temozolomide (TMZ) is a common clinical drug widely used to treat glioblastoma multiforme and gradual astrocytoma. Despite its widespread use in cancer treatment, issues remain with the solubility and stability of TMZ, which can be addressed by synthesizing novel pharmaceutical cocrystals. This study sought to enhance the physiochemical properties of TMZ. To this end, a pioneering pharmaceutical cocrystal of TMZ and caffeic acid (CAF), 2TMZ–CAF·0·5H2O (2:1:0.5) was synthesized and characterized using a solution method. The cocrystal structure was analyzed by molecular surface electrostatic potential (MESP), Hirshfeld surface analysis, and 2D fingerprinting. They were further characterized by single crystal X-ray diffraction, power X-ray diffraction, proton nuclear magnetic resonance, thermogravimetry-differential scanning calorimetry, dynamic vapor sorption, and Fourier transform infrared spectroscopy. Furthermore, the hygroscopicity, stability, and solubility of the TMZ–CAF cocrystal were investigated to evaluate their pharmaceutical applicability. In the asymmetric unit of the novel synthesized cocrystal, two complementary molecules of TMZ and CAF were found, forming planar hydrogen bonding pairs such as O–H···O, N–H···O, and O–H···N. Moreover, the cocrystals exhibited excellent stability compared to TMZ alone and regulated solubility during accelerated stabilization and dissolution processes. Hence, the cocrystals boast characteristics that can circumvent the rapid release of TMZ. In conclusion, the newly synthesized 2TMZ–CAF·0·5H2O cocrystals demonstrate enhanced physiochemical properties, including improved stability and solubility, compared to pure TMZ. This suggests potential utility in drug delivery systems. Additionally, the findings underscore the growing importance of pharmaceutical cocrystals in drug development, with implications for advancing cancer treatment and drug formulation strategies.

Nuclear Magnetic Resonance (NMR) Metabolomics: Current Applications in Equine Health Assessment

Metabolomics can allow for the comprehensive identification of metabolites within biological systems, at given time points, in physiological and pathological conditions. In the last few years, metabolomic analysis has gained popularity both in human and in veterinary medicine, showing great potential for novel applications in clinical activity. The aim of applying metabolomics in clinical practice is understanding the mechanisms underlying pathological conditions and the influence of certain stimuli (i.e., drugs, nutrition, exercise) on body systems, in the attempt of identifying biomarkers that can help in the diagnosis of diseases. Proton Nuclear Magnetic Resonance spectroscopy (1H-NMR) is well tailored to be used as an analytical platform for metabolites’ detection at the base of metabolomics studies, due to minimal sample preparation and high reproducibility. In this mini-review article, the scientific production of NMR metabolomic applications to equine medicine is examined. The research works are very different in methodology and difficult to compare. Studies are mainly focused on exercise, reproduction, and nutrition, other than respiratory and musculoskeletal diseases. The available information on this topic is still scant, but a greater collection of data could allow researchers to define new reliable markers to be used in clinical practice for diagnostic and therapeutical purposes.

Waste snail shells-derived mixed oxide catalyst for efficient transesterification of vegetable oil: Towards sustainable biodiesel production

This study explores the transesterification process of soybean oil for the production of biodiesel, utilizing an innovative mixed oxide catalyst obtained from discarded snail shells powder. The catalyst synthesis involved a thermal treatment at 900°C for 120 min, predominantly yielding calcium oxide (CaO). In order to evaluate its properties, we carried out a thorough characterization using various analytical techniques. The study explores the impact of crucial variables on the transesterification reaction, such as reaction time (from 30 to 150 min), methanol-to-oil ratio (from 3:1–18:1), and catalyst concentration (from 0.5% to 4% by weight). Optimal conditions emerged with a 90-min reaction time, a 12:1 methanol-to-oil ratio, and a 2% catalyst loading, yielding an impressive biodiesel conversion rate of approximately 93%. The validity of biodiesel conversion was confirmed through Fourier transform infrared spectroscopy (FTIR) and Proton Nuclear Magnetic Resonance Spectroscopy (1 H NMR). The resultant biodiesel exhibited highly favorable characteristics, including an acid value of 0.85 mg of KOH/g, a density of 886.8 kg/m3, and a viscosity of 4.6 mm2/s. These measurements align with the standards set forth in EN 14214 and ASTM D6751 regarding biodiesel quality. The utilization of waste snail shells powder as a precursor for synthesizing the mixed oxide catalyst presents a promising approach for the sustainable production of biodiesel from soybean oil, offering a sustainable and efficient approach to biofuel production.

Quantitative analysis of molecular interactions in κ-carrageenan-Isovanillin biocomposite for biodegradable packaging and pharmaceutical applications using NMR, TOF-SIMS, and XPS approach

This study explores the molecular interactions and structural changes in κ-carrageenan crosslinked with isovanillin to create a biocomposite material suitable for hard capsule and bio-degradable packaging applications. Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy revealed chemical changes in the conjugate molecule, indicating improved electronegativity due to intermolecular hydrogen bonding between κ-carrageenan and isovanillin. Time-of-flight Secondary Ion Mass Spectrometry (ToF-SIMS) analysis revealed enhanced ion intensity due to intermolecular interactions, particularly between sulphate and hydrogen ions. X-ray Photoelectron Spectroscopy (XPS) study demonstrated that κ-carrageenan and isovanillin form stronger hydrogen bonds, with a shift in binding energy indicating higher electronegativity. These findings shed light on the molecular mechanisms that underpin the formation of the biocomposite material, as well as its potential for use in hard capsule and biodegradable packaging materials, addressing the need for sustainable alternatives in the pharmaceutical and packaging industries while also contributing to environmental conservation.

Preparation of ruminal fluid and serum samples from beef cattle for nuclear magnetic resonance based–metabolomics

ABSTRACT We evaluated different sample preparation methods for one-dimensional proton nuclear magnetic resonance metabolomics analysis of beef cattle ruminal fluid and serum. After collecting and pooling samples from five bulls (all of which received the same diet and were subjected to the same management conditions), we prepared the samples with the following methods: metabolite extraction using methanol and chloroform (M + C); metabolite extraction using methanol, chloroform and acetone (M + C + A); filtering with a 3-kDa filter; and filtering with a 2-μm filter. We evaluated the methods based on the spectral quality, reproducibility, ease of processing, speed and relative cost. The use of 2-μm filters did not produce good-spectra quality for serum samples, but it was a promising method for ruminal fluid. The yields of metabolites were similar for the the solvent extractions (22 metabolites for ruminal fluid and 29 for serum samples), but lower compared with the filter methods (31 metabolites for ruminal fluid and 47 for serum samples). The filters resulted in a higher concentration of metabolites and better reproducibility. In conclusion, the 2-μm and 3-kDa filter methods represent a suitable way to prepare biological samples from beef cattle for nuclear magnetic resonance – based metabolomics.

Verification of In Vitro Anticancer Activity and Bioactive Compounds in Cordyceps Militaris-Infused Sweet Potato Shochu Spirits.

Many liqueurs, including spirits infused with botanicals, are crafted not only for their taste and flavor but also for potential medicinal benefits. However, the scientific evidence supporting their medicinal effects remains limited. This study aims to verify in vitro anticancer activity and bioactive compounds in shochu spirits infused with Cordyceps militaris, a Chinese medicine. The results revealed that a bioactive fraction was eluted from the spirit extract with 40% ethanol. The infusion time impacted the inhibitory effect of the spirit extract on the proliferation of colon cancer-derived cell line HCT-116 cells, and a 21-day infusion showed the strongest inhibitory effect. Furthermore, the spirit extract was separated into four fractions, A-D, by high-performance liquid chromatography (HPLC), and Fractions B, C, and D, but not A, exerted the effects of proliferation inhibition and apoptotic induction of HCT-116 cells and HL-60 cells. Furthermore, Fractions B, C, and D were, respectively, identified as adenosine, cordycepin, and N6-(2-hydroxyethyl)-adenosine (HEA) by comprehensive chemical analyses, including proton nuclear magnetic resonance (1H-NMR), Fourier transform infrared spectroscopy (FT-IR), and electrospray ionization mass spectrometry (ESI-MS). To better understand the bioactivity mechanisms of cordycepin and HEA, the agonist and antagonist tests of the A3 adenosine receptor (A3AR) were performed. Cell viability was suppressed by cordycepin, and HEA was restored by the A3AR antagonist MR1523, suggesting that cordycepin and HEA possibly acted as agonists to activate A3ARs to inhibit cell proliferation. Molecular docking simulations revealed that both adenosine and cordycepin bound to the same pocket site of A3ARs, while HEA exhibited a different binding pattern, supporting a possible explanation for the difference in their bioactivity. Taken together, the present study demonstrated that cordycepin and HEA were major bioactive ingredients in Cordyceps militaries-infused sweet potato shochu spirits, which contributed to the in vitro anticancer activity.

Characterisation and critical processes identification for production of herbal preparations using 1H-NMR and chemometrics: A case study of Trichosanthis Pericarpium injection.

Herbal preparations are extensively utilised for the treatment of diseases in Asian countries. However, the variations in origin, climate, and production processes can lead to inconsistencies in the quality of herbal preparations. Existing quality control methods only target a few components in the finished product but ignore the control in the pharmaceutical process. Therefore, this study intends to develop a comprehensive component analysis method for intermediates in the pharmaceutical process to reveal the change patterns of substances and deepen the process understanding. This study aims to develop a rapid and comprehensive process characterisation and critical process identification method for herbal preparations. Six batches of Trichosanthis Pericarpium injection (TPI) intermediates were collected from the production process. Proton nuclear magnetic resonance (1H-NMR) spectra were acquired for qualitative and quantitative analysis of the se intermediates. Subsequently, chemometrics were used to identify critical processes and potential chemical markers. A total of 39 components in intermediates were identified, and the transfer of 25 components during the production process was investigated. Column chromatography was determined as the critical process. Nine components were identified as chemical markers. The application of 1H-NMR facilitated a comprehensive reflection of the chemical composition information of process intermediates, enabling investigations into the transfer of multi-component substances and accurate identification of critical processes and chemical markers.

Fermentation Analytical Technology (FAT): Monitoring industrial E. coli fermentations using absolute quantitative 1H NMR spectroscopy

BackgroundTo perform fast, reproducible, and (absolute) quantitative measurements in an automated manner has become of paramount importance when monitoring industrial processes, including fermentations. Due to its numerous advantages – including its inherent quantitative nature – Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy provides an ideal tool for the time-resolved monitoring of fermentations. However, analytical conditions, including non-automated sample preparation and long relaxation times (T1) of some metabolites, can significantly lengthen the experimental time and make implementation in an industrial set up unfeasible. ResultsWe present a high throughput method based on Standard Operating Procedures (SOPs) and 1H NMR, which lays the foundation for what we call Fermentation Analytical Technology (FAT). Our method was developed for the accurate absolute quantification of metabolites produced during Escherichia coli industrial fermentations. The method includes: (1) a stopped flow system for non-invasive sample collection followed by sample quenching, (2) automatic robot-assisted sample preparation, (3) fast 1H NMR measurements, (4) metabolites quantification using multivariate curve resolution (MCR), and (5) metabolites absolute quantitation using a novel correction factor (k) to compensate for the short recycle delay (D1) employed in the 1H NMR measurements. The quantification performance was tested using two sample types: buffer solutions of chemical standards and real fermentation samples. Five metabolites – glucose, acetate, alanine, phenylalanine and betaine – were quantified. Absolute quantitation ranged between 0.64-3.40 mM in pure buffer, and 0.71-7.76 mM in real samples. SignificanceThe proposed method is generic and can be straight forward implemented to other types of fermentations, such as lactic acid, ethanol and acetic acid fermentations. It provides a high throughput automated solution for monitoring fermentation processes and for quality control through absolute quantification of key metabolites in fermentation broth. It can be easily implemented in an at-line industrial setting, facilitating the optimization of the manufacturing process towards higher yields and more efficiently/sustainable use of resources.

Compositional, structural, and functional characterization of fucoidan extracted from Sargassum polycystum collected from Saint Martin's Island, Bangladesh

Fucoidan is a sulphated polysaccharide with diversified biological activities commonly found in brown seaweeds. In our present study, fucoidan was extracted from Sargassum polycystum collected from Saint Martin's Island in three different extraction methods. The composition of the fucoidans was determined by measuring the total carbohydrate, sulfate, uronic acid, fucose, and protein contents. Fourier-transform infrared spectroscopy (FT-IR) and Proton nuclear magnetic resonance (1H NMR) were studied to determine the structural groups of extracted fucoidans. Functional activities were analyzed by antioxidant activity and anti-diabetic activity assay. Fucoidan yield was obtained highest in the acid extraction method (0.061 ± 0.007 g/g), followed by the water extraction method (0.058 ± 0.005 g/g) and salt extraction method (0.041 ± 0.005 g/g). Water extracted fucoidan showed the highest carbohydrate content (62.97 %), uronic acid content (6.46 %), and protein content (2.62 %). Sulphate content (28.56 %) was highest in salt extracted fucoidan, whereas fucose content (24.0 %) was highest in water extracted fucoidan. FT-IR and 1H NMR analysis confirm several characteristic picks for the extracted fucoidans. Extracted fucoidans presented comparable antioxidant activity, but salt-extracted fucoidan presented the highest DPPH radical scavenging assay (86.85 ± 0.74 %, IC50 = 0.03 mg/mL), ABTS radical scavenging assay (65.13 ± 0.92 %, IC50 = 1.94 mg/mL), Phosphomolybdenum assay (4.356 ± 0.11) and Nitric Oxide (NO) radical scavenging assay (57.08 ± 0.52 %, IC50 = 3.73 mg/mL) in dose-dependency manner. Further anti-diabetic activity assay resulted in the highest α-amylase inhibition activity (62.82 ± 1.36 %, IC50 = 2.30 mg/mL) and α-glucosidase inhibition activity (55.73 ± 0.84 %, IC50 = 3.71 mg/mL) by salt-extracted fucoidan. These functional potentials of seaweed may add significant value to the development of functional food and pharmaceutical materials.

Direct electrospinning for producing multiple activity nanofibers consisting of aggregated luteolin/hydroxypropyl-gamma-cyclodextrin inclusion complex

Hydroxypropyl-gamma-cyclodextrin (HPγCD) inclusion complex nanofibers (Lut/HPγCD-IC-NF) containing Luteolin (Lut) were prepared by electrospinning technology. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) spectra confirmed the formation of Lut/HPγCD-IC-NF. Scanning electron microscopy (SEM) images showed that the morphology of Lut/HPγCD-IC-NF was uniform and bead-free, suggesting that self-assembled aggregates, macromolecules with higher molecular weights, were formed by strong hydrogen bonding interactions between the cyclodextrin inclusion complexes. Confocal laser scanning microscopy (CLSM) images showed that Lut was distributed in Lut/HPγCD-IC-NF. Proton nuclear magnetic resonance (1H NMR) spectroscopy revealed the change in chemical shift of the proton peak between Lut and HPγCD, confirming the formation of inclusion complex. Thermogravimetric analysis (TGA) proved that Lut/HPγCD-IC-NF had good thermal stability. The phase solubility test confirmed that HPγCD had a solubilizing effect on Lut. When the solubility of HPγCD reached 10 mM, the solubility of Lut increased by 15-fold. The drug loading test showed that the content of Lut in fibers reached 8.57 ± 0.02 %. The rapid dissolution experiment showed that Lut/HPγCD-IC-NF dissolved within 3 s. The molecular simulation provides three-dimensional evidence for the formation of inclusion complexes between Lut and HPγCD. Antibacterial experiments showed that Lut/HPγCD-IC-NF had enhanced antibacterial activity against S. aureus. Lut/HPγCD-IC-NF exhibited excellent antioxidant properties with a free radical scavenging ability of 89.5 ± 1.1 %. In vitro release experiments showed Lut/HPγCD-IC-NF had a higher release amount of Lut. In conclusion, Lut/HPγCD-IC-NF improved the physicochemical properties and bioavailability of Lut, providing potential applications of Lut in the pharmaceutical field.

α-Zr(HPO4)2·H2O: As an effective and recoverable catalyst for the synthesis of a family of quinoxalines in semi-aqueous conditions

In our work, we have established a straightforward and friendly process for the preparation of a family of quinoxaline. This method relies on using α-Zr(HPO4)2·H2O as a catalyst and an ethanol/water mixture as an ecological solvent. Firstly, we prepared α-Zr(HPO4)2·H2O by a simple hydrothermal procedure and conducted comprehensive characterization employing various analytical methods. On the other hand, we produced the quinoxalines by means of a condensation reaction between 1,2-dicarbonyl compounds and various 1,2-diamines. The synthesized quinoxaline and its derivative products were characterized by melting point, proton, and carbon nuclear magnetic resonance analysis. As a result, the optimal reaction conditions that resulted in a high yield (97–98 %) were an amount of catalyst of 0.03 g, a stirring time of 8 min, a volume of solvent of 2 mL, and a reaction temperature of 50 °C. This approach is advantageous due to its simple and eco-friendly procedure, green solvent, quick reaction time, low cost, and high yields. Additionally, it offers the possibility to recycle the catalyst for a minimum of five cycles with no decrease in its catalytic activity.

1H-NMR metabolomics investigation of CSF from children with HIV reveals altered neuroenergetics due to persistent immune activation.

HIV can invade the central nervous system (CNS) early during infection, invading perivascular macrophages and microglia, which, in turn, release viral particles and immune mediators that dysregulate all brain cell types. Consequently, children living with HIV often present with neurodevelopmental delays. In this study, we used proton nuclear magnetic resonance (1H-NMR) spectroscopy to analyze the neurometabolic profile of HIV infection using cerebrospinal fluid samples obtained from 17 HIV+ and 50 HIV- South African children. Nine metabolites, including glucose, lactate, glutamine, 1,2-propanediol, acetone, 3-hydroxybutyrate, acetoacetate, 2-hydroxybutyrate, and myo-inositol, showed significant differences when comparing children infected with HIV and those uninfected. These metabolites may be associated with activation of the innate immune response and disruption of neuroenergetics pathways. These results elucidate the neurometabolic state of children infected with HIV, including upregulation of glycolysis, dysregulation of ketone body metabolism, and elevated reactive oxygen species production. Furthermore, we hypothesize that neuroinflammation alters astrocyte-neuron communication, lowering neuronal activity in children infected with HIV, which may contribute to the neurodevelopmental delay often observed in this population.

1H-NMR Metabolomic Study of the Mushroom Pleurotus djamor for the Identification of Nematocidal Compounds

Due to the increasing populations of anthelmintic-resistant gastrointestinal nematodes and as a consequence of the adverse effects of synthetic drugs, this study focuses on the search for secondary metabolites with nematocidal activity from the edible mushroom Pleurotus djamor using The proton nuclear magnetic resonance (1H-NMR) metabolomics. The highest activity was shown by the ethyl acetate fractions of mycelium (EC50 290.8 µg/mL) and basidiomes (EC50 282.7 µg/mL). Principal component analysis (PCA) and hierarchical data analysis (HCA) of the 1H-NMR metabolic profiles data showed that the ethanolic extracts, the ethyl acetate, butanol, and water fractions from mycelium have different metabolic profiles than those from basidiomes, while low polarity (hexane) fractions from both stages of fungal development show similar profiles. Orthogonal partial least squares discriminant analysis (OPLS-DA) allowed the identification of signals in the 1H-NMR metabolic profile associated with nematocidal activity. The signals yielded via OPLS-DA and bidimensional NMR analysis allowed the identification of uracil as a component in the ethyl acetate fraction from basidiomes, with an EC50 of 237.7 µg/mL. The results obtained showed that chemometric analyses of the 1H-NMR metabolic profiles represent a viable strategy for the identification of bioactive compounds from samples with complex chemical profiles.

1H NMR spectroscopic analysis of metabolite changes in kauri leaf apoplastic washing fluid following inoculation with Phytophthora agathidicida

Phytophthora agathidicida is responsible for a devastating dieback disease that threatens the survival of Agathis australis (kauri), an ancient conifer species endemic to New Zealand. To develop durable control strategies against kauri dieback disease, a better understanding of the host metabolites necessary for the growth and survival of P. agathidicida during in planta growth, particularly during colonisation of the apoplastic environment, where early contact between host and pathogen cells is made, is required. As a starting point to address this knowledge gap, we investigated changes in the metabolite profile of apoplastic washing fluid (AWF) samples harvested from kauri leaves following either mock inoculation or inoculation with P. agathidicida. AWF was extracted from leaves of kauri saplings and inoculated with P. agathidicida on cellophane membranes or cellophane membranes without the pathogen as a control. The metabolite profile of the AWF samples was then analysed via proton nuclear magnetic resonance (1H NMR) spectroscopy at 24 hours and 10 days post-inoculation, and changes investigated relative to the control. Some changes in the metabolite profile of kauri AWF samples following P. agathidicida inoculation were observed using 1H NMR spectroscopy, including a decrease in sucrose and an increase in glucose resulting from the breakdown of more complex carbohydrates. Our results suggest that P. agathidicida modifies or utilises metabolites present in the leaf apoplast of kauri, including carbohydrates that serve as a source of nutrition. These results provide possible new insights into the nutritional requirements of P. agathidicida during apoplastic colonisation of kauri.

Protective effects of oyster polypeptide on cyclophosphamide-induced immunosuppressed rats.

Oyster polypeptide (OP) is a mixture of oligopeptides extracted from oysters through enzyme lysis, separation, and purification. It is associated with immunomodulatory effects, but the underlying mechanisms are not known. This study therefore combined proton nuclear magnetic resonance (1H-NMR) urinary metabolomics and 16S rRNA gene sequencing of the gut microbiome to determine the immunoprotective mechanisms of OP in rats subjected to cyclophosphamide-induced immunosuppression. Oyster polypeptide restored the body weight and the structure of spleen and thymus in rats with cyclophosphamide-induced immunosuppression. It upregulated the levels of white blood cells (WBCs), hemoglobin (HGB), platelets (PLT), red blood cells (RBCs), immunoglobulin G (IgG), immunoglobulin M (IgM), cytokines such as interleukin‑6 (IL-6) and tumor necrosis factor-α (TNF-α), and increased the numbers of CD3+ and CD4+ T cells in the immunosuppressed rats. The 1H-NMR metabolomics results showed that OP significantly reversed the levels of ten metabolites in urine, including 2-oxoglutarate, citrate, dimethylamine, taurine, N-phenylacetylglycine, alanine, betaine, creatinine, uracil, and benzoate. The 16S rRNA gene sequencing results showed that OP restored the gut microbiome homeostasis by increasing the abundance of beneficial bacteria and reducing the abundance of pathogenic bacteria. Finally, a combination of metabolomics and microbiomics found that the metabolism of taurine and hypotaurine, and the metabolism of alanine, aspartate, and glutamate were disturbed, but these metabolic pathways were restored by OP. This study demonstrated that OP had immunoprotective effects in rats with cyclophosphamide-induced immunosuppression by restoring key metabolic pathways and the gut microbiome homeostasis. Our findings provide a framework for further research into the immunoregulatory mechanisms of OP and its potential use in drugs and nutritional supplements. © 2024 Society of Chemical Industry.

Controlled Magnetite Grafted Poly(glycidyl methacrylates) for Heavy Metal Absorption and Recovery via SET-LRP

A versatile magnetite based stringent polymer for effective metal capture was prepared by reacting iron oxide based initiator with glycidyl methacrylate monomer via single-electron transfer living radical polymerization (SET-LRP) technique. The versatile grafted polymer was successfully synthesized by metal catalyzed living radical polymerization using the catalyst system Cu/N,N,N',N'',N'''-pentamethyldiethylenetriamine as the ligand. The structural confirmation of the initiator and the grafted polymer was analyzed by using instrumentation methods such as proton nuclear magnetic resonance spectroscopy, UV-visible, TGA, SEM and gel permeation chromatography for molecular weight measurements. As the polymerization time increased, both the conversion and the molecular weight were observed to increase linearly with time. Narrow dispersed lower polydispersity index (PDI) and dispensable magnetite-g-PGMA was utilized for the extract of toxic lead from the wastewater. Sustained binding was observed due to the presence of epoxide ring in the repeating units of the polymer and recovered by magnetic effect. The material shows good stability as evident by TGA curves and better affinity to toxic lead as observed by UV-visible and SEM techniques.

Synthesis and Characterization of Hexahydropyrimidines and Their New Derivatives

Three new hexahydropyrimidine derivatives 1a – 1c were successfully synthesized using the Mannich-type reaction. Furthermore, the synthesis of three amino bases 2a – 2c was achieved through the reduction reaction of pyrimidine compounds using hydrazine, followed by the substitution reaction of nitro groups at diverse positions. Subsequently, one of the synthesized amino base derivatives 2c underwent conversion into seven Schiff bases 3a – 3g via a condensation reaction involving the aforementioned amino base derivative and a selection of benzaldehyde derivatives. Four amide compounds 4a – 4d have been synthesized by a reaction of the secondary amine group in the pyrimidine ring with benzoyl chloride. The products were subjected to comprehensive characterization employing rigorous analytical techniques, including FT-), 1H-NMR (Proton Nuclear Magnetic Resonance Spectroscopy), and LC-MS (Liquid Chromatography–Mass Spectrometry). Additionally, the Molecular Electrostatic Potential (MEP) study was carried out to further investigate the properties of the synthesized compounds. The yields of the three methods used to synthesise new hexahydropyrimidine derivatives varied depending on the specific substituents added to the aromatic ring.

Thermo-thickening/amphoteric polymer nanocomposite incorporating vinyl-functionalized nano-silica as a viscosifier for high-salt and ultra-high temperature water-based drilling fluids

In the relentless extraction of oil and gas from deeper reservoirs, the harsh geological conditions pose significant rheological challenges for conventional polymer viscosifiers. Hence, the spotlight has turned to the unique potential of thermo-thickening polymers to enhance drilling fluid performance. In this study, a novel polymer nanocomposite (VMS-ATA) was designed to associate thermo-thickening responses, amphoteric characteristics, and vinyl-functionalized nano-silica (VMS) as nanofillers for the formation of a thermally stable polymer nanocomposite-bentonite hybrid system. VMS-ATA was prepared via in-situ polymerization under optimal synthetic conditions, and the unique chemical structure was analyzed using various techniques such as Fourier transform spectroscopy, proton nuclear magnetic resonance, elemental analysis, thermogravimetric analysis, X-ray spectroscopy, transmission electron microscopy, and scanning electron microscopy. The study systematically investigated the enhancement of in-situ covalent bonding characteristics of VMS on the thermo-thickening behavior of VMS-ATA, while comparing it with amine-nano-silica (AMS) incorporated in a polymer composite (AMS-CGBA). TGA analysis revealed that VMS-ATA exhibits excellent thermal stability compared to AMS-CGBA, attributed to the thermally stable VMS (370 °C) compared to AMS (355 °C). Interestingly, VMS-ATA displayed relatively stable and prolonged thermo-thickening responses (100–200 °C) owed to high thermal-induced activation responses above the lower critical solution temperature (LCST) in both salt-free and saturated salt contamination. The rheological results of VMS-ATA viscosity retention at 220 °C and 20 wt% NaCl, exceeded 60 %, which is twice that of AMS-CGBA-containing fluids. As demonstrated, VMS-ATA and AMS-CGBA exhibited similar macro-interactions with rigid imidazole and caprolactam rings, but significantly differed in their micro-interactions owed to in-situ covalent binding induced by VMS compared to hydrogen bonding in AMS. This breakthrough exhibited the potential of VMS nanofillers to effectively maintain thickening response by facilitating efficient heat distribution to minimize rapid viscosity decay and revolutionize the landscape of high-salt and high-temperature (HSHT) drilling applications.