Search Results (226)

Background: Stable isotope-based analytical methods have brought about a significant transformation in the study of energy nutrient metabolism, enabling precise in vivo measurement of metabolic fluxes at systemic, tissue, and organ-specific levels in both healthy and diseased states. The regulation of these metabolic fluxes is governed by dynamic interactions between proteins, lipids, carbohydrates, and their precursors—such as glucose, fatty acids, and amino acids—as well as final metabolic products. Discussion: Advanced analytical technologies, including nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS), which can offer enhanced precision, have been developed for investigating nutrient metabolism and fluxes in humans, providing precise information on metabolic pathways. These techniques have primarily utilized stable isotopes, such as ²H, ¹³C, ¹⁵N, and ¹⁸O, which have largely replaced radioactive isotopes and are now central to metabolic research. These isotopes have been used to label glucose, fatty acids, or amino acids—the main biomolecular precursors—enabling detailed investigation at systemic, tissue, and organ-specific levels of carbohydrate, lipid, and protein metabolism, and revealing pathway alterations associated with diseases conditions, such as diabetes, non-alcoholic fatty liver disease, cardiovascular disorders, and cancer. The use of deuterium oxide (D₂O) has allowed for long-term metabolic studies, providing a cost-effective and less invasive means to monitor metabolic changes over days to months. Total daily energy expenditure can be measured in free living conditions by the doubly stable isotopes ²H- and ¹⁸O-labeled water method. Stable isotope tracing, combined with advanced imaging and modeling, has also been instrumental in assessing body composition, energy expenditure, and nutrient bioavailability. Collectively, these methods have expanded our understanding of human physiology and disease, supporting the development of novel diagnostic tools, the identification of new biomarkers, and the tailoring of nutritional and therapeutic interventions. Conclusions: This review aimed to provide an overview of the applications of stable isotopes for the study of energy nutrient metabolic pathways. The ongoing integration of stable isotope approaches with artificial intelligence, omics technologies, and miniaturized detection techniques could promise to further refine our understanding of human metabolism and drive advances in personalized medicine. Full article

Background: Refugees arriving from conflict zones often continue to experience trauma and are at increased risk of anxiety and depression. Those seeking asylum form a group at higher risk of suffering adverse mental health outcomes, with higher needs for psychosocial and therapeutic care. This study aimed to determine metabolic changes potentially associated with psychological distress in refugees from Syria, using a saliva-based metabolomics approach via proton nuclear magnetic resonance (1H NMR) spectroscopy. Methods: Participants were recruited from Lethbridge Family Services and categorized into high and low stress burden groups using questionnaires assessing depression (PHQ-9) and generalized anxiety (GAD-7). Salivary metabolomic profiles from 26 female and 32 male participants were analyzed using supervised and unsupervised multivariate statistical methods to identify metabolic differences linked to composite stress, depression, and anxiety. Results: Salivary metabolic profiles showed the most prominent differences associated with anxiety in female participants and depression in male participants. Multivariate statistical analyses identified 31 metabolites and 13 biological pathways that were significantly altered according to mental health status, with the greatest changes observed in glycolysis/gluconeogenesis, sphingolipid metabolism, and taurine/hypotaurine metabolism. Conclusions: These findings indicate that salivary 1H NMR metabolomic profiling can identify a quantifiable “metabolic fingerprint” related to impaired mental health and psychological distress in a cost-effective, objective, and non-invasive way. This analytical strategy shows potential as a screening tool to support effective decision-making, enabling early identification of individuals at highest risk who require timely emotional and medical support. Full article

The genus Psiadia (Asteraceae), widely distributed in Madagascar and the Mascarene Islands (Mauritius, La Réunion, Rodrigues), is traditionally used to treat bronchitis, asthma, colds, abdominal pain, and other inflammatory disorders. However, few studies have scientifically validated these traditional medicinal uses. To assess P. dentata as a valuable source of bioactive natural products, a combined ¹H NMR-based metabolomic, molecular networking, and phytochemical study was conducted. Multivariate analysis (PLS-DA) of crude extracts from Psiadia species collected on Reunion Island enabled rapid discrimination of active extracts from P. dentata and revealed two methoxylated flavonoids and one coumarin as metabolites correlated with its antiplasmodial and anti-inflammatory activities. Additionally, UHPLC-DAD-ESI-QTOF-MS/MS molecular networking approach enabled detailed chemical profiling of this species, allowing the annotation of 25 compounds (1–25) in this species. Subsequent phytochemical investigation of P. dentata leaves led to the isolation and identification of 25 metabolites, including nine new diterpenes (26–34), one new coumarin (35), and 15 known compounds (1–8, 11, 18, 19 and 36–39) from the diterpenoid, flavonoid, and coumarin families. The structures of the new compounds were elucidated using spectroscopic methods, including extensive 1D and 2D NMR and HRESIMS analyses. Biological evaluation of the isolated compounds showed that compounds 1, 7, 26 and 27 showed antiplasmodial activity against Plasmodium falciparum (3D7 strain, IC₅₀ = 7.25–13.46 μM). Compounds 7, 26, 27, 31 and 32 inhibited nitric oxide production (IC₅₀ = 0.87–27.71 μM), indicating potential anti-inflammatory effects. Only compound 1 displayed moderate cytotoxicity against HepG2 and HT29 cancer cell lines (IC₅₀ = 25.67 and 18.35 μM, respectively). Full article

Very preterm infants with immature kidneys exhibit high vulnerability to acute kidney injury (AKI). While AKI is associated with adverse outcomes, serum-creatinine-based diagnostics prove unreliable in early risk assessment of kidney damage. This pilot study investigated ¹H-NMR spectroscopy-based metabolomics for the identification of very-low-birth-weight (VLBW < 1500 g) infants at risk of AKI before and during indomethacin treatment for patent ductus arteriosus (PDA). Longitudinal urine samples (0 h, 12 h, 36 h, 84 h, 120 h, 14 d, 28 d) from 12 VLBW infants receiving indomethacin for hemodynamically significant PDA were analyzed by ¹H-NMR spectroscopy. In total, 150 urinary metabolites were annotated and single-metabolite and multivariate analyses were performed. At 36 h after treatment initiation, three patients (25%) developed AKI (KDIGO criteria). Principal component analysis (PCA) revealed significant differences in urinary metabolic profiles between the AKI and non-AKI groups 12 h after indomethacin initiation. Before treatment, five metabolites were significantly lower in the AKI group: adenine, creatine, dimethylglycine, 1-methylnicotinamide, and methylmalonic acid. Urinary creatine/creatinine (AUC 0.97) and 1-methylnicotinamide/creatinine (AUC 0.93) exhibited promising prognostic accuracy for the prediction of AKI. 1-methylnicotinamide/creatinine concentrations remained persistently reduced during the study. In conclusion, urinary metabolomics, particularly creatine and 1-methylnicotinamide levels, may serve as valuable non-invasive biomarkers for identifying VLBW infants at risk of AKI. Full article

Saffron (Crocus sativus L.) is widely cultivated for the spice obtained from the stigmas, while the remaining floral biomass is discarded as biowaste. Accessing the phytochemical composition of these residues could enable their valorization as a low-cost and sustainable resource for nutraceutical applications. In this context, a quantitative ¹H NMR-based metabolite profiling approach, complemented by HPLC-DAD and LC-MS, was employed to comprehensively characterize saffron biowaste. A total of 40 metabolites were identified and quantified by NMR, including amino acids (611.1 ± 36.5 mg/100 g FW), carbohydrates (2801.4 ± 33.7 mg/100 g FW), lipids (702.7 ± 28.2 mg/100 g FW), and saffron-specific compounds such as crocin (596.6 ± 21.5 mg/100 g FW), picrocrocin (1126.3 ± 18.9 mg/100 g FW), safranal (398.4 ± 14.8 mg/100 g FW), and crocetin (13.4 ± 0.4 mg/100 g FW). Targeted fractionation further allowed the identification of kaempferol 3-O-sophoroside (15.44 ± 0.61% w/w in dry ethanolic extract) and 3-hydroxy-γ-butyrolactone. Overall, the results highlight the rich metabolite composition of saffron production waste and support its potential reuse as a valuable source of functional ingredients within a circular economy framework. Full article

Bromodomain-containing protein 9 (BRD9) belongs to the non-canonical BAF chromatin remodeling complex and represents a relevant therapeutic target in pathologies featuring dysregulated epigenetic control. The absence of clinically validated inhibitors and the need for diversified chemical entities highlight the interest in identifying new scaffolds targeting this protein. In this study, Saturation Transfer Difference Nuclear Magnetic Resonance (STD NMR) was employed to assess its suitability for characterizing BRD9–ligand interactions within a fragment-based discovery framework. STD NMR conditions were first optimized using the known BRD9 ligand 1, verifying the presence of interaction signals. A pharmacophore-based virtual screening campaign was then performed using libraries of commercially available fragments, leading to the selection of a novel isatin derivative, i.e., compound 2, whose binding was demonstrated in AlphaScreen assays. STD NMR experiments provided epitope mapping consistent with the predicted binding mode, thus supporting the stability of the interaction in solution. Moreover, a competitive STD experiment demonstrated displacement of 2 by a reference ligand, confirming the binding within the canonical BRD9 pocket. Overall, this study establishes STD NMR as a reliable approach for probing BRD9–ligand interactions and for the identification and validation of BRD9-targeting scaffolds suitable for future structure-guided optimization. Full article

Cholesterol plays a fundamental role in the human body—it stabilizes cell membranes, modulates gene expression, and is a precursor to steroid hormones, vitamin D, and bile salts. Its correct level is crucial for homeostasis, while both excess and deficiency are associated with serious metabolic and health consequences. Excessive accumulation of cholesterol leads to the development of atherosclerosis, while its deficiency disrupts the transport of fat-soluble vitamins. Magnetic resonance spectroscopy (MRS) enables the detection of cholesterol esters and the differentiation between their liquid and crystalline phases, but the technical limitations of clinical MRI systems require the use of dedicated coils and sequence modifications. This study demonstrates the feasibility of using MRS to identify cholesterol-specific spectral signatures in atherosclerotic plaque through ex vivo analysis. Using a custom-designed experimental coil adapted for small-volume samples, we successfully detected characteristic cholesterol peaks from plaque material dissolved in chloroform, with spectral signatures corresponding to established NMR databases. To further enhance spectral quality, a deep-learning denoising framework based on a 1D U-Net architecture was implemented, enabling the recovery of low-intensity cholesterol peaks that would otherwise be obscured by noise. The trained U-Net was applied to experimental MRS data from atherosclerotic plaques, where it significantly outperformed traditional denoising methods (Gaussian, Savitzky–Golay, wavelet, median) across six quantitative metrics (SNR, PSNR, SSIM, RMSE, MAE, correlation), enhancing low-amplitude cholesteryl ester detection. This approach substantially improved signal clarity and the interpretability of cholesterol-related resonances, supporting more accurate downstream spectral assessment. The integration of MRS with NMR-based lipidomic analysis, which allows the identification of lipid signatures associated with plaque progression and destabilization, is becoming increasingly important. At the same time, the development of high-resolution techniques such as μOCT provides evidence for the presence of cholesterol crystals and their potential involvement in the destabilization of atherosclerotic lesions. In summary, nanotechnology-assisted MRI has the potential to become an advanced tool in the proof-of-concept of atherosclerosis, enabling not only the identification of cholesterol and its derivatives, but also the monitoring of treatment efficacy. However, further clinical studies are necessary to confirm the practical usefulness of these solutions and their prognostic value in assessing cardiovascular risk. Full article

Reliable taxonomy of biological producers is essential for finding new natural substances. A recent study morphologically re-examined 21 accessed vouchers to confirm multiple reported misidentifications and suggested marine sponges from the genus Rhabdastrella as the only known source of the isomalabaricane triterpenoids. The present study aimed to find isomalabaricane-containing sponges among the samples collected during seven marine expeditions to the Vietnam waters of the South China Sea, accompanied with their identification confirmed using morphological and molecular (18S rRNA and 28S rRNA) analyses. As a result, nine sponges identified as Rhabdastrella globostellata were found to contain isomalabaricanes in their extracts. A chemical investigation of the R. globostellata (PIBOC O63-136) specimen led to the isolation of nine isomalabaricane triterpenoids including the new compound 1, of which the chemical structure was elucidated based on HRESIMS and NMR data. Subsequently, a combination of LC–MS/MS, multivariate statistical analysis, and feature-based molecular networking was applied to detect, annotate, and characterize the isomalabaricane chemical diversity across the nine R. globostellata specimens. As a result, two primary chemotypes containing individual sets of annotated compounds were discovered within the Vietnamese population of this sponge. Moreover, obtained data showed a series of new extremely rare isomalabaricanes in R. globostellata extracts including nitrogen-containing metabolites and glycosides of this structural class. Full article

The first systematic chemical investigation on Sinularia mollis resulted in the isolation and identification of 36 seven-membered cembranolides, including 14 new compounds named sinumollolides A–N (1–14) and 22 known analogs (15–36) by HSQC-based small molecule accurate recognition technology (SMART). Their structures were characterized by spectroscopic methods (1D/2D NMR and UV), HRESIMS, quantum chemical calculations (DP4+ analysis and ECD calculations), and X-ray diffraction analysis. In zebrafish assays, compounds 1, 2, 4, and 5 exhibited anti-inflammatory activity at 20 μM by inhibiting the number of macrophages around the neuromasts, with inhibition rates ranging from 30.4% to 45.6%. Moreover, the two most bioactive and less toxic compounds, 1 and 5, featuring a 14-membered macrocyclic lactone scaffold with several hydroxyl groups and a seven-membered α, β-unsaturated lactone moiety, can inhibit inflammation by suppressing the secretion of inflammatory cytokines at 10 μM in LPS-stimulated BV-2 cells. Full article

Composting is an effective biotechnological process for transforming agro-industrial residues into stabilized and nutrient-rich organic amendments. However, the molecular mechanisms underlying organic matter transformation remain poorly resolved. In this study, a mixture of winery by-products and poultry manure was composted under controlled aeration and monitored through high-field ¹H NMR spectroscopy of the water-extractable organic matter (WEOM), followed by interval-based chemometric analysis. The NMR spectra revealed distinct compositional trends, including the rapid depletion of amino acids and carbohydrates, the transient accumulation of low-molecular-weight organic acids, and the gradual enrichment in aromatic and phenolic compounds associated with humification processes. Chemometric modeling using Partial Least Squares (PLS) regression and its interval variants (iPLS and biPLS) enabled accurate prediction of composting time (r ≈ 0.95) and identification of diagnostic spectral intervals corresponding to key metabolites. These findings demonstrate the capability of NMR-based molecular profiling, combined with multivariate modeling, to elucidate the biochemical pathways of composting and to provide quantitative indicators of compost stability and maturity. Full article

1-Butyl-3-methylimidazolium (bmim) ionic liquids (ILs) are widely used for lignocellulose fractionation, yet their role extends beyond mere solvents. This study revealed that bmim-based ILs act as active chemical reagents, modifying the lignin structure in an anion-dependent manner. Thermal treatment (80–150 °C) of spruce dioxane lignin with [bmim]OAc, [bmim]Cl, and [bmim]MeSO₄ resulted in two distinct transformation pathways. In [bmim]MeSO₄, acidic catalysis dominates, leading to lignin condensation (increase in weight-average molecular weight, M_w, to 15.2 kDa at 150 °C) and intense sulfur incorporation (up to 9.9%) via anion-derived methylation/sulfation. Conversely, [bmim]OAc promotes depolymerization (decrease in M_w to 3.6 kDa) and efficient covalent bonding of the bmim cation to lignin (up to 10.8 cations per 100 aromatic units and a 6.5% nitrogen content at 150 °C), preventing condensation. Two-dimensional NMR and HPLC-HRMS analyses revealed the formation of a C–C bond between the C₂ atom of the imidazole ring and the α-carbon of the phenylpropane lignin fragments and allowed for the identification of a number of individual nitrogen-containing lignin oligomers in the [bmim]OAc-treated samples. Their formation likely proceeds via nucleophilic addition of the N-heterocyclic carbene (NHC), derived from the bmim cation by deprotonation with the highly basic acetate anion, to aldehyde groups. The action of [bmim]Cl primarily induces acid-catalyzed transformations of lignin with minimal covalent modification. These findings redefine imidazolium ILs as reactive media in biorefining, where their covalent interactions can influence the properties of lignin but complicate its native structure and the recyclability of the IL. Full article

The exploration potential, storage capacity, and exploitability of the deep shale-gas reservoirs are governed by various characteristics of their pore networks. Conventional methods cannot fully capture these features across scales, highlighting the need for an integrated, multi-technique approach. In this study, pore structure and connectivity of the Wufeng–Longmaxi Formation (Luzhou Block) were investigated using Scanning Electron Microscopy (SEM) with the Mosaic Acquisition and Positioning System (MAPS), ImageJ (ImageJ 2.14.0)-based pore analysis, Mercury Intrusion Porosimetry (MIP), and Nuclear Magnetic Resonance (NMR). Based on the samples from eight reservoir layers of Wufeng-WF and Longmaxi-LM1₁^1–7, shale pore connectivity was classified into three grades. Grade A layers, with connected pore volumes above 0.0067 cm³/g and porosity exceeding 1.75%, showed trimodal NMR pore-size distributions and strong connectivity among micro, meso, and macropores. Grade B layers exhibited bimodal pore distributions, moderate pore connectivity (0.0057–0.0067 cm³/g; 1.55–1.75% porosity), and sponge-like organic pores with isolated mineral pores. Grade C layers, with connected pore volumes below 0.0057 cm³/g, showed poor connectivity and unimodal NMR responses. Connected pores (1–100 nm) contributed 20–35% of total pore volume, reflecting the strong heterogeneity of the formation. Interconnected inorganic mineral-hosted pores were found to link locally connected organic pores, forming continuous pore networks. The qualitative and quantitative identification of the pore connectivity of shale reservoirs with MAPS, MIP, and NMR approach provides a robust framework for evaluating shale pore connectivity and identifying high-quality reservoir targets. Full article

Agarwood from Aquilaria agallocha, known as chim-hyuang in Korea, is widely distributed throughout Southeast Asia and has traditionally been used to treat asthma, pain, and gastrointestinal disorders. As part of our ongoing efforts to identify bioactive metabolites from natural sources, a phytochemical investigation of the EtOAc fraction of A. agallocha extract led to the isolation and identification of four compounds, N-trans-feruloyltyramine (1), (3R,5R)-octahydrocurcumin (2), 1,7-bis(4-hydroxyphenyl)heptane (3), and trans-caffeoyltyramine (4), via HPLC purification and LC/MS-based analysis. Structural elucidation of the isolated compounds was achieved using NMR spectroscopy, LC/MS, and high-resolution electrospray ionization mass spectrometry (HR-ESIMS). The absolute configuration of compound 2 was further confirmed by optical rotation and electronic circular dichroism (ECD) analyses. All isolated compounds (1–4) were evaluated for their inhibitory activity against tau protein aggregation. Notably, compound 2 exhibited a 43.7% reduction in tau aggregation at 20 μM, without cytotoxicity at the same concentration. These findings indicate that phytochemicals from A. agallocha, particularly the diarylheptanoid compound 2, hold promise as natural lead candidates for the development of therapeutic agents targeting tau protein aggregation. Full article

Background/Objectives: Animal health remains a critical issue that directly impacts economic sustainability through animal welfare and production. In small ruminants, the gastrointestinal parasite Haemonchus contortus can lead to anemia and possibly mortality, since parasite burden can be considerable and is challenging to control. Small ruminant health can be affected by poor diet and environmental conditions that lead to changes in the metabolic balance. The link between animal health and metabolic profiles has been investigated in the past. These studies have shed important light on physiological changes by identifying dietary and disease biomarkers. This study aimed to correlate the metabolite signature of feces from goats, having two levels of Haemonchus contortus infection, grazing on two different forages (Bermudagrass and Sunn Hemp). Methods: Fecal samples were taken from goats grazing either Sunn Hemp or Bermudagrass pastures, with naturally variable Haemonchus contortus loads. Samples were evaluated using ¹H-NMR and LC/MS methods to describe and compare metabolic patterns under varied forage conditions between low and high Fecal Egg Count (FEC). Results: Our findings indicated no significant difference using univariate analyses but identified 10 discriminatory features using multivariate analyses for Bermudagrass and Sunn Hemp using ¹H-NMR. With LC-MS, we found 14 significantly different features (p < 0.05, FC > 2), 115 discriminatory features for Bermudagrass and 113 in Sunn Hemp from multivariate analyses. Combining the findings of the two approaches suggested that Haemonchus contortus influenced several pathways associated with the metabolism of amino acids and energy conversion. Conclusions: The analysis of metabolome changes across both forages may help in revealing novel knowledge and accurate identification of possible biomarkers for gastrointestinal parasites. Further study is needed to validate the potential biomarker before deploying diagnostic tools based on the metabolomics indicators for early parasite diagnosis. Full article

Cytisine and coumarin derivatives are promising for the creation of new drugs with antiarrhythmic, antiepileptic, antidiabetic, anti-inflammatory, and antimicrobial effects. In this study, the molecular structure of the cytisine and coumarin derivative in solution, a recently synthesized substance N-(2-oxo-2H-chromen-3-carbonyl)cytisine, was studied by NMR and UV-Vis absorption spectroscopies accompanied by a theoretical study based on density functional theory. The existence of four stable conformers associated with the rotation of the cytisine part relative to the coumarin part due to a sufficiently flexible intermediate part has been demonstrated. Their energy and concentrations were estimated. In the 1H and 13C NMR spectra, peaks were found that correspond to individual conformers and groups of conformers. The UV-visible absorption spectrum also revealed spectral features associated with different conformers. It was shown that the obtained results are consistent with earlier studies about conformational state identification in cytisine derivatives functionalized with flexible parts. The obtained theoretical and experimental results provide useful spectroscopic information for such conformer identification in this and structurally similar substances. Full article