Search Results (473)

Although the impact of COVID-19, caused by SARS-CoV-2, may appear to have diminished in recent years, the emergence of new variants still continues to cause significant global health and economic challenges. While numerous metabolomic studies have explored serum-based alterations linked to the infection, investigations utilizing urine as a biological matrix remain notably limited. This gap is especially significant given the potential advantages of urine, a non-invasive and easily obtainable biofluid, in clinical settings. In the context of patients in intensive care units (ICUs), temporal monitoring through such non-invasive samples may offer a practical and effective approach for tracking disease progression and tailoring therapeutic interventions. This study retrospectively explored the longitudinal metabolomic alterations in COVID-19 patients admitted to the ICU, stratified into three prognostic outcome groups: healthy discharged (HD), polyneuropathic syndrome (PS), and Exitus. A total of 32 urine samples, collected at four distinct time points per patient during April 2020 and preserved at −80 °C, were analyzed by proton nuclear magnetic resonance (¹H-NMR) spectroscopy for comprehensive metabolic profiling. Statistical evaluation using two-way ANOVA and ANOVA–Simultaneous Component Analysis (ASCA) identified significant prognostic variations (p < 0.05) in the levels of taurine, 3-hydroxyvaleric acid and formic acid. Complementary supervised classification via random forest modeling yielded moderate predictive performance with out-of-bag error rate of 40.6% based on prognostic categories. Particularly, taurine, 3-hydroxyvaleric acid and formic acid levels were highest in the PS group. However, no significant temporal changes were observed for any metabolite in analyses. Additionally, metabolic pathway analysis conducted using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database highlighted the “taurine and hypotaurine metabolism” pathway as the most significantly affected (p < 0.05) across prognostic classifications. Harnessing urinary metabolomics, as indicated in our preliminary study, could offer valuable insights into the dynamic metabolic responses of ICU patients, thereby facilitating more personalized and responsive critical care strategies in COVID-19 patients. Full article

Cerebrospinal fluid (CSF) is a key biological matrix that reflects the physiological and pathological states of the central nervous system (CNS). It supports brain function by regulating ionic balance, facilitating molecular transport, and clearing metabolic waste. In this article, we present a standardized protocol for CSF collection along with an integrative multiplatform metabolomic workflow that combines proton nuclear magnetic resonance spectroscopy (¹H-NMRS) and high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS). Integrating these complementary analytical modalities enhances metabolite coverage and improves analytical robustness, enabling a more comprehensive and reliable characterization of the CSF metabolome. This workflow supports the discovery of potential biomarkers and advances our understanding of neurochemical alterations within the CNS. Full article

The pH of fruit and vegetable juices is usually around 4.0. To adapt to the pH of fruit and vegetable juices, we developed a highly branched pectin as a natural stabiliser, whose polarity is well suited to conditions under weakly acidic conditions. The pectin content of jujube is high (about 2.0%), in which the polysaccharide content of Muzao (2.0–4.8%) is generally higher than the average value of the jujube. To separate the weak polar pectin in jujube, we extracted the crude polysaccharide (ZMP) with 4 times the volume of alcohol. Then we used Diethylaminoethyl (DEAE) cellulose (DEAE-52) ion-exchange chromatography to separate ZMP, and selected the fraction eluted with 0.2 M NaCl for gel purification to obtain ZMP2. After the hydrolysis of ZMP2 with TFA, four fractions, namely ZMP2n5, ZMP2y5, ZMP2n1, and ZMP2y1, were obtained. The purity, molecular weight, and monosaccharide composition of the above four fractions were determined. It was found that each fraction of ZMP2 contained large amounts of galacturonic acid (GalA) and glucuronic acid (GlcA), indicating that ZMP2 was most likely pectin, making it the natural, polar stabiliser we sought. To further determine the primary structure of ZMP2, we also performed FT-IR spectroscopy; methylation; one-dimensional mapping, including Proton Nuclear Magnetic Resonance (¹H NMR), Carbon-13 Nuclear Magnetic Resonance (¹³C NMR) and Distortionless Enhancement by Polarization Transfer 135 (DEPT 135); and two-dimensional mapping, including Correlation Spectroscopy (1H-1H COSY), Heteronuclear Single Quantum Coherence (HSQC), Heteronuclear Multiple-Bond Correlation (HMBC), and Nuclear Overhauser Effect Spectroscopy (NOESY). In summary, the primary structure of ZMP2 should be as follows: the main chain is connected as →4)-α-D-GalAp-(1→3)-β-D-Galp-(1→, while the end glycosidic bonds of α-D-Galp-(1→ and α-L-Araf-(1→5)-α-L-Araf-(1→ are attached to the main chain by O-3 and O-6 bonds from →3,4)-α-D-GalAp-(1→ and →3,6)-β-D-GalAp-(1→, respectively. Full article

Wine, as a high-value product, is vulnerable to counterfeiting. To tackle increasingly sophisticated fraud, innovative analytical approaches are required. However, they must undergo rigorous validation. Proton nuclear magnetic resonance spectroscopy (¹H-NMR) is intrinsically quantitative, reproducible, and fast, making it a promising tool for official control. This study presents the development and validation of a standardised and fully automated workflow for the quantification of 20 oenologically relevant compounds, including organic acids, sugars, alcohols, esters, phenolics, and an alkaloid. The method combines optimised sample preparation, external quantification standards, spectrometer calibration, and a dedicated R package (RnmrQuant1D) for fully automated spectral processing, enabling high-throughput and operator-independent analysis. Validation was performed under intermediate precision according to OIV metrological standards, evaluating accuracy, precision, robustness, limits of quantification, and measurement uncertainty. The results demonstrated excellent linearity, trueness, and reproducibility, matching the targeted analytical performance. Measurement uncertainties were estimated both by conventional linear modelling and by a dynamic approach better suited to detection limits. The workflow is easy to implement, requires minimal sample consumption, and substantially reduces operator bias. Beyond validating a robust method, this study provides a framework for harmonised, transferable ¹H-NMR workflows that could support large-scale databases, integration with chemometric models, and ultimately, ¹H-NMR’s recognition as a relevant method for wine authentication and quality control. This work fills a crucial gap in wine analysis by uniting practical application and rigorous methods, enabling broader adoption in control laboratories worldwide. Full article

Ceftobiprole is a novel and promising antibiotic; however, the direct pharmacological use of its native form is limited by its low water solubility. The first part of this study provides a deeper insight into the physicochemical properties of this drug. One- and two-dimensional nuclear magnetic resonance (NMR) spectra in D₂O were recorded, and a complete assignment of ¹H and ¹³C signals was achieved with the support of quantum mechanical calculations. The combined results from capillary electrophoresis and NMR confirmed the cationic nature of ceftobiprole at pH values well below 3 and the protonation of the secondary amino group, thus supporting the theoretically predicted dominant protonation states. Molecular dynamics simulations revealed that zwitterionic ceftobiprole molecules associate through hydrogen bonding, whereas in the cationic form, the attractive forces involve weaker π-π and stacking interactions. The use of ceftobiprole in its native form in pharmaceutical formulations was made possible through the development of a novel freeze-dried cyclodextrin-based delivery system. Consequently, the second part of this article focuses on evaluating the biological properties of this system (ceftobiprole/maleic acid/sulfobutylether-β-cyclodextrin in a molar ratio of 1:25:4), including its antibacterial activity against the most common pneumonia-causing pathogens and its cytotoxicity towards normal and cancer cells. Full article

Dietary supplements are a means of increasing the consumption of beneficial ω-3 lipids. Their composition in acyl groups, the structures supporting them, and their minor component profile can influence their oxidative stability and even their health effects. However, information about all these features is not always provided to consumers. The purpose of this study was to characterise via Proton Nuclear Magnetic Resonance (¹H NMR) a variety of ω-3 lipid-rich supplements available in the Spanish market, addressing the previously mentioned aspects, together with their oxidative status. Despite not being indicated on the labelling, ethyl esters were found in most fish oil concentrate-based supplements, sometimes as the main lipid class. Furthermore, considerable levels of partial glycerides were present in some samples. Minor components include tocopherols, sterols, terpenic compounds from added flavourings, and vitamin A, many of them with antioxidant and/or bioactive potential. In addition, other unexpected compounds such as BHT and ethanol were detected. Some discrepancies between real sample composition and label information have been noticed regarding the tocopherol profile. Most supplements contained small quantities of hydroperoxides and considerably fewer aldehydes, with significant differences observed among samples, which were not directly associated with their unsaturation degree. These outcomes reinforce the usefulness of ¹H NMR to provide data about key factors determining the quality of ω-3 lipid-rich supplements in a very simple and fast way. Full article

Background/Objectives: Metabolites are low-molecular-weight organic compounds (<1 kDa) that act as intermediates and end products of cellular metabolism. Their characterization provides valuable information on the nutritional quality, functionality, and potential health impacts of food products. In the dairy sector, proton nuclear magnetic resonance (¹H NMR) spectroscopy has emerged as a powerful tool for metabolite profiling, enabling the simultaneous identification and quantification of diverse compounds. In this study, ¹H NMR was applied to characterize and compare the metabolic composition of whey, a major by-product of cheese and yogurt production, and whey protein concentrate (WPC-80), a whey derivative containing approximately 80% protein by weight and rich in essential amino acids. Methods: Five whey and four WPC-80 samples from a single Parmigiano Reggiano dairy plant were collected, each representing a biologically independent sample. Statistical evaluation was performed using Mann–Whitney U tests to identify significantly different metabolites between groups, while principal component analysis and partial least squares discriminant analysis were employed to assess group separation and determine discriminant metabolites. Results: The results revealed marked compositional differences: whey was higher in dimethyl sulfone, succinate, orotate, fumarate, and lactose (p < 0.05), whereas WPC-80 contained significantly higher levels of histidine, formate, glucose + glucose-6-phosphate, acetate, and choline (p < 0.05). Moreover, metabolites such as hippurate, valine, lactate + threonine, and uracil were exclusively found on whey and not in WPC-80, likely due to processing steps such as ultrafiltration. Conclusions: These findings highlight the metabolic distinctions introduced by WPC-80 processing from Parmigiano Reggiano whey and provide insights into the nutritional and functional characteristics of whey-derived products. Such knowledge can inform the design of innovative dairy ingredients and functional foods, with potential benefits for both industry applications and consumer health. Full article

Cocoa pod husk (CPH) is a potential material to produce value-added products. The objective of this study was to optimize the microwave-assisted hydrothermal pretreatment (MA-HTP) of CPH and CPH hemicellulose (HMC-CPH) using only water as the extraction medium, in combination with response surface analysis (RSA), Box–Behnken design (BBD), and proton nuclear magnetic resonance identification and quantification (¹H NMR Qu) to provide an efficient protocol for the extraction of mono- and disaccharides, as a novel method for which no precedent was found. The methodology consisted of 15 CPH MA-HTPs and 15 HMC-CPH MA-HTPs (triplicate) designed by RSA-BBD; the experimental variables were time, temperature, and power, and the response was the concentration of extraction products. Glucose, sucrose, and fructose were identified as products of the extractions by ¹H NMR. With 95% confidence, higher sucrose content was determined for CPH (45.62%) compared to HMC-CPH (17.34%), high fructose content for both CPH and HMC-CPH (37.88% and 35.37%, respectively), and minimal glucose concentrations were obtained in both CPH and HMC-CPH (4.57% and 0.93%, respectively). Using RSA-BBD, optimal temperature, power, and time points were predicted for glucose CPH: 135.4 °C, 180.6 W, and 5.8 min; sucrose: 154.3 °C, 256.3 W, and 20. 2 min; fructose 129.5 °C, 173.8 W, and 5.27 min. For HMC-CPH, the optimal conditions were as follows: glucose: 142.2 °C, 204.4 W, and 10.5 min; sucrose: 148.8 °C, 215.6 W, and 14.3 min; fructose: 151.6 °C, 231.6 W, and 13 min. Full article

Gelatin methacryloyl (GelMA) hydrogels are widely used in tissue engineering because of their tunable mechanical and biological properties. However, many studies have arbitrarily selected key synthesis parameters, such as methacrylic anhydride (MA) concentration, (lithium phenyl-2 4 6-trimethyl-benzoyl phosphinate) LAP concentration, GelMA content, UV exposure time, and reaction duration, without clear justification. This study aimed to systematically optimize GelMA hydrogel fabrication and evaluate the mechanical and biological performances of the resulting hydrogels for craniofacial muscle tissue engineering. Hydrogels were synthesized following a standardized protocol, and the reaction progress was confirmed via proton nuclear magnetic resonance (¹H-NMR). The swelling ratio, degradation behavior, compressive strength, and metabolic activity (AlamarBlue assay using C2C12 myoblasts) were assessed. Statistical analysis was performed using independent t-tests and one-way ANOVA with Tukey’s post hoc test (p < 0.05). The results showed that small variations in MA concentration and reaction time significantly affected the hydrogel properties. Higher GelMA concentrations (10–20%) enhanced the mechanical strength but reduced the biological activity. LAP ≥ 0.5% and prolonged UV exposure lowered metabolic activity, whereas 0.1% LAP with 1–2 min of UV exposure provided an optimal balance. These findings provide a reproducible framework for GelMA fabrication and establish a foundation for developing tailored biomaterials for muscle tissue engineering. Full article

Aim: Nephrotic syndrome (NS) represents a complex glomerular disorder with significant clinical heterogeneity across pediatric and adult populations. Although glucocorticosteroids have constituted the mainstay of therapeutic intervention for more than six decades, primary treatment resistance manifests in approximately 20% of pediatric patients and 50% of adult cohorts. Steroid-resistant nephrotic syndrome (SRNS) is associated with substantially greater morbidity compared to steroid-sensitive nephrotic syndrome (SSNS), characterized by both iatrogenic glucocorticoid toxicity and progressive nephron loss with attendant decline in renal function. Based on this, the current study aims to develop a robust machine learning (ML) model integrated with explainable artificial intelligence (XAI) to distinguish SRNS and identify important biomarker candidate metabolites. Methods: In the study, biomarker candidate compounds obtained from proton nuclear magnetic resonance (1 H NMR) metabolomics analyses on plasma samples taken from 41 patients with NS (27 SSNS and 14 SRNS) were used. We developed ML models to predict steroid resistance in pediatric NS using metabolomic data. After preprocessing with MICE-LightGBM imputation for missing values (<30%) and standardization, the dataset was randomly split into training (80%) and testing (20%) sets, repeated 100 times for robust evaluation. Four supervised algorithms (XGBoost, LightGBM, AdaBoost, and Random Forest) were trained and evaluated using AUC, sensitivity, specificity, F1-score, accuracy, and Brier score. XAI methods including SHAP (for global feature importance and model interpretability) and LIME (for individual patient-level explanations) were applied to identify key metabolomic biomarkers and ensure clinical transparency of predictions. Results: Among four ML algorithms evaluated, Random Forest demonstrated superior performance with the highest accuracy (0.87 ± 0.12), sensitivity (0.90 ± 0.18), AUC (0.92 ± 0.09), and lowest Brier score (0.20 ± 0.03), followed by LightGBM, AdaBoost, and XGBoost. The superiority of the Random Forest model was confirmed by paired t-tests, which revealed significantly higher AUC and lower Brier scores compared to all other algorithms (p < 0.05). SHAP analysis identified key metabolomic biomarkers consistently across all models, including glucose, creatine, 1-methylhistidine, homocysteine, and acetone. Low glucose and creatine levels were positively associated with steroid resistance risk, while higher propylene glycol and carnitine concentrations increased SRNS probability. LIME analysis provided patient-specific interpretability, confirming these metabolomic patterns at individual level. The XAI approach successfully identified clinically relevant metabolomic signatures for predicting steroid resistance with high accuracy and interpretability. Conclusions: The present study successfully identified candidate metabolomic biomarkers capable of predicting SRNS prior to treatment initiation and elucidating critical molecular mechanisms underlying steroid resistance regulation. Full article

This study was designed for the analytical method development and validation for Calcium butyrate (CAB) using High-Performance Liquid Chromatography (HPLC). ¹H and ¹³C Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared (FTIR) spectroscopy analysis were carried out to examine the molecular structure. For HPLC analysis, a blend of acetonitrile and phosphoric acid solution (0.1%) (20:80) (v/v) was used as a mobile phase. A C18 column (5 µm, 250 × 4.6 mm) was used as a stationary phase. The eluent of CAB was monitored with a UV detector at a wavelength of 206 nm and a flow rate of 1 mL/min. According to the results, FTIR and NMR spectra were consistent with the structural characteristics of CAB, and the expected proton and carbon signals were observed. During the HPLC analysis, due to the ionization of CAB, three distinct retention times were observed in the chromatograms at 3.4, 4.5, and 7.4 min. The validation was performed according to ICH guidelines. The obtained results demonstrated that the analytical method was successfully validated, with LOD values of 1.211, 0.606, and 1.816 µg/mL, and LOQ values of 3.670, 1.835, and 3.676 µg/mL. The assay displayed a linear range of 5–1000 µg/L concentration and was found suitable for further formulation content analysis. Full article

In this study, we report the synthesis of three new derivatives of betulinic acid, a pentacyclic triterpenoid known for its antitumor activity. These derivatives were synthesized via amide bond formation at the C-28 position using 3-[(Ethylimino)methylidene]amino-N,N-dimethylpropan-1-amine (EDC)/Hydroxybenzotriazole (HOBt) activation and various amines as nucleophiles. The synthesized compounds were characterized by nuclear magnetic resonance (NMR) techniques, including proton (¹H), carbon-13 (¹³C), COSY, HSQC, and DEPT, as well as ultraviolet–visible (UV-VIS) spectroscopy, Fourier-transform infrared (IR) and elemental analysis. This work highlights the potential of semi-synthetic modification of betulinic acid to enhance anticancer properties while addressing challenges in solubility and bioavailability. Further structural optimization and formulation studies are warranted to improve drug-like properties and therapeutic applicability. Full article

The applications of electromagnetic (EM) field treatment on water in agriculture have garnered increasing attention as a sustainable method to enhance plant growth, water-use efficiency, and metabolic performance. A growing body of evidence suggests that exposure to EM fields can affect water molecules, possibly by influencing hydrogen bonding dynamics, the structuring of water clusters, and electrokinetic properties of the water molecules. These alterations are thought to correlate with plant physiological performance. The methodology of the study was divided into two parts. The first part focused on the preparation of electromagnetically treated water. The second part involved applying this treated water to spinach plants. The present study investigates the physiological responses of Spinacia oleracea L. to irrigation with electromagnetically treated water (EMTW), focusing on elucidating the potential mechanisms that may underlie the observed effects. EMTW was generated using a solenoid-based system operating in dual-frequency ranges (100–1000 Hz and 10–100 kHz), which has been previously shown to influence both the microbiological and electrokinetic properties of aqueous systems. To evaluate the structural and functional implications of EMTW, a combined methodological approach was employed, integrating proton nuclear magnetic resonance (¹H-NMR) spectroscopy, density functional theory (DFT) modeling of water hydrogen bonds and clusters, and comprehensive plant physiological assessments. Plants were cultivated under both controlled and field conditions to assess consistency across environmental settings. Physiological measurements demonstrated that EMTW irrigation increased photosynthetic rate by ~80%, transpiration by 49–67%, stomatal conductance by 78–129%, intercellular CO₂ concentration by 42–80%, and chlorophyll content by 9.3–9.5% compared to control samples. Additionally, phenoloc and flavonoid contents were elevated by 7.4% and 7.6%, respectively, in field-grown plants. These enhancements were statistically significant (p < 0.001 or p < 0.01) under both laboratory and field conditions, confirming the robustness of the observed effects. Full article

Bacterial cellulose, a biopolymer synthesised by microorganisms, exhibits remarkable structural, optical, and electronic properties. This study utilised a range of photon- and electron-based techniques, including X-ray diffraction, proton nuclear magnetic resonance (¹H-NMR), photoacoustic spectroscopy, and scanning electron microscopy, to thoroughly characterise BC. While XRD and NMR directly employ photons to probe the structure and composition, PAS indirectly converts absorbed photons into phonons to evaluate optoelectronic features. SEM revealed a dense nanofibrillar network with fibrils measuring 10–75 nm in diameter. XRD confirmed the crystalline nature of BC, identifying characteristic peaks associated with cellulose Iα. ¹H-NMR relaxation analysis differentiated between the ordered and disordered cellulose regions. PAS determined an optical bandgap of 2.97 eV and identified defect states between 3.6 and 2.9 eV, including a prominent peak at 3.35 eV, likely resulting from oxygen vacancies, hydroxyl modifications, or UV-induced rearrangements. These defects modify BC’s electronic structure, suggesting potential for bandgap engineering. The integration of these complementary techniques provides a multidimensional understanding of BC’s morphology, crystallinity, and electronic behaviour, underscoring its potential in bioelectronics, advanced composites, and biomedical applications. Full article

Sodium magadiite (Na-Mgd) was hydrothermally prepared and converted to its protonic (H-Mgd) form by reaction with hydrochloric (HCl) solution. The obtained products were studied as adsorbents for basic blue 41 (BB-41) removal from polluted aqueous solution. Na-Mgd and H-Mgd were characterized by different techniques. Powder X-ray (PXRD) diffraction data confirmed a pure Na-Mag phase and its conversion to acidic form (H-Mgd) with shift in d₀₀₁ value from 1.54 nm to 1.12 nm. X-ray fluorescence (XRF) data supported the exchange of Na cations by protons for H-Mag. ²⁹Si magic angle spinning nuclear magnetic resonance (MAS-NMR) indicated a change in the local environment of silicon nucleus when Na-Mgd was treated with HCl solution. The BB-41 removal dyes were investigated throughout the batch process. Effects of selected parameters, for example, the adsorbent dosage, pH of the BB-41 solution, pH of the H-Mag solid, and starting concentration, were explored. The equilibrium data were fitted to the Langmuir and Freundlich isotherm models. The maxima removal capacities of Na-Mgd and H-Mgd were 219 mg/g and 114 mg/g, respectively. The regeneration and reusability tests were performed using initial concentrations of 50 mg/L and 200 mg/L for seven cycles. The efficiency was maintained for 5 to 6 cycles with a decline of 10% using low initial concentration; however, a decline of efficiency to 30 to 50% was achieved when a higher initial concentration was employed after 3 to 4 regeneration tests for Na-Mgd and H-Mgd samples. Adsorber batch design using the Langmuir and Freundlich isotherm parameters was used to predict its performance for commercial usage. The predicted masses of H-Mgd were higher than those of Na-Mgd to treat different effluent volumes contaminated with 200 mg/L of BB-41 dyes at desired removal percentages. Full article