Search Results (45)

Benign prostatic hyperplasia (BPH) is an age-related disorder increasingly linked to chronic inflammation and redox imbalance, yet its systemic oxidative and nitrosative profile remains insufficiently characterized. In this cross-sectional study, fasting serum samples were collected from 47 men with clinically confirmed BPH scheduled for transurethral resection of the prostate and 40 healthy controls. We assessed antioxidant status (thiols, total antioxidant capacity), lipid peroxidation (malondialdehyde, 4-hydroxynonenal), protein nitration (3-nitrotyrosine), glycoxidation markers (Amadori products, advanced glycation end products (AGE)-associated fluorescence), and tryptophan metabolism indices (tryptophan, kynurenine, N′-formylkynurenine). Compared with controls, BPH patients showed significantly lower antioxidant capacity and thiol levels, together with increased lipid peroxidation and protein nitration. AGE-associated fluorescence was modestly elevated, whereas Amadori products and advanced oxidation protein products did not differ significantly. Tryptophan metabolism was markedly altered, with lower tryptophan and higher kynurenine and N′-formylkynurenine, indicating activation of the kynurenine pathway. After false discovery rate correction, most redox biomarkers remained significant. Multivariable logistic regression confirmed independent associations of lipid peroxidation, nitrosative stress, and kynurenine pathway activation with BPH after adjustment for age and metabolic parameters. These findings support a role for systemic oxidative and inflammatory mechanisms in BPH pathophysiology, although confirmation in age-matched and longitudinal studies is needed. Full article

Protein glycation is a nonenzymatic modification that links sugar chemistry to molecular aging and chronic disease. Sequential reactions involving Schiff bases, Amadori products, and reactive α dicarbonyl intermediates generate advanced glycation end products (AGEs) that irreversibly alter protein structure and function. AGEs also act as ligands for the receptor for advanced glycation end products (RAGE), initiating oxidative stress, inflammation, and tissue remodeling. This review synthesizes the molecular pathways of AGE formation, their structural diversity, and the biological factors influencing glycation kinetics. Advances in analytical detection methods—including fluorescence spectroscopy, LC–MS/MS, and immunochemical approaches—are highlighted for their role in monitoring AGE accumulation. Particular attention is given to the contribution of glycation to diabetes, cardiovascular disease, neurodegeneration, and cancer, alongside emerging therapeutic strategies to limit AGE formation or block AGE–RAGE signaling. Glycation thus represents a central mechanism in human disease pathogenesis and an emerging therapeutic frontier. Full article

High-temperature Daqu (HTD)’s quality determines the characteristics and yield of the Chinese sauce-aroma baijiu. However, winter production frequently encounters challenges such as fermentation instability and metabolic fluctuations, primarily stemming from complex, unmonitored microenvironmental changes within the HTD pile. This study established a closed-loop system linking the microenvironment, HTD quality, microbiome, and metabolome. Through continuous monitoring of the winter fermentation pile’s microenvironmental conditions and integrating multi-omics analyses, we revealed that CO₂ concentration within fermentation piles is the core factor causing quality variations in HTD. By breaking the respiratory bottleneck formed by carbon dioxide (CO₂) accumulation through the turning anaerobic stress can be alleviated, thereby driving metabolic succession. The study found that vertical CO₂ concentration heterogeneity severely restricts the enrichment of aerobic core functional microbial communities such as the Bacillus species. This directly blocks key metabolic pathways including amino acid metabolism and energy supply via ABC transporters. Moreover, the specific accumulation of Amadori products further confirms that this low-temperature environment under CO₂ stress causes the Maillard reaction to stall at intermediate stages. Consequently, this study proposes a steady-state control strategy centered on oxygen and CO₂ gas characteristics. By actively regulating the gaseous microenvironment to eliminate metabolic heterogeneity, it provides theoretical support for standardizing traditional fermentation processes. Full article

Protein glycation and oxidation contribute to the pathogenesis of neurodegenerative diseases. This study evaluated the antiglycative and antioxidative effects of donepezil, rivastigmine, galantamine, memantine, lamotrigine, sodium valproate, and carbamazepine using bovine serum albumin (BSA) as a model protein. Glycation was induced with fructose, ribose, or methylglyoxal (MGO), and oxidation with chloramine T (ChT). Concentrations of glycation products—Amadori products (APs), amyloid cross-β structure (βA), argpyrimidine (ARG), crossline (CRO), vesperlysine (VES), pentosidine (PEN), total AGEs and glycoxidation products—dityrosine (DT), kynurenine (KN), N-formylkynurenine (NFK) as well as oxidation biomarkers, total thiols (TTs), protein carbonyls (PCs), and advanced oxidation protein products (AOPPs), were determined via spectrophotometric and spectrofluorimetric methods. Molecular docking and a systematic literature review (PRISMA) complemented the experimental data. Lamotrigine showed the strongest antiglycative and antioxidative effects, surpassing aminoguanidine in reducing ARG, PEN, DT, and NFK levels. In contrast, donepezil markedly increased APs, βA, ARG, VES, DT, and PEN, suggesting proglycative and pro-oxidative activity. Docking revealed a high affinity of donepezil for RAGE (–7.2 kcal/mol), possibly explaining its impact on carbonyl stress. Overall, anti-dementia drugs showed weak to moderate antiglycative potential, with lamotrigine being the most effective. Full article

Msalais is a type of wine made by a series of processes such as boiling and fermentation from Hotan red grape juice. The Maillard reaction occurs during the boiling of the grape juice. The Amadori compound is a product of the early stage of the Maillard reaction, which has physiological activities such as antioxidation, anti-hypertension, and anti-hyperglycemia. The purpose of this study was to develop Msalais rich in Amadori compounds by utilizing the fermentative capabilities of different yeasts. The optimal fermentation process was obtained by response surface optimization, with the key parameters as follows: Saccharomyces cerevisiae Y4 and Wickerhamomyces anomalus Y2 (as the fermenting yeasts), fermentation temperature of 28 °C, fermentation time of 14 days, yeast inoculation amount of 2% (V/V), and ratio of Saccharomyces cerevisiae to non-Saccharomyces cerevisiae of 2:1. At the same time, HPLC-ELSD was used to detect Amadori compounds in the product of this optimal fermentation process. The contents of Fru-Pro and Fru-Asp in the optimal fermentation process were 0.2867 ± 0.0115 g/L and 0.0203 ± 0.0014 g/L, respectively, which were 0.0702 g/L and 0.026 g/L higher than those of commercially available commercial Msalais (0.2165 ± 0.0022 g/L and 0.0177 ± 0.0008 g/L, respectively). With the increase in the content of Amadori compounds, the antioxidant activity was significantly improved. The DPPH free radical scavenging ability was 116.37 ± 1.79 μmol Trolox/sample, which was 53.01 μmol Trolox/L sample higher than that of commercial Msalais. The ABTS free radical scavenging ability was 142.51 ± 1.98 μmol Trolox/L sample, which was 68.23 μmol Trolox/L sample higher than that of commercial Msalais. The total oxygen free radical absorption capacity was 132.74 ± 6.36 μmol Trolox/L sample, which was 60.12 μmol Trolox/L higher than that of the commercial Msalais. Compared with traditional Msalais produced by natural fermentation, the quality of Msalais fermented by specific yeasts has been significantly improved. These results provide a reliable basis for the fermentation of Msalais by specific yeasts and its quality optimization. Full article

Buckwheat honey is known for its high antioxidant activity, yet the compounds responsible for this effect have not been fully identified. This study used LC-MS-based untargeted metabolomics to investigate the metabolite profile of buckwheat honey and its relationship with antioxidant activity and total phenolic content, assessed by DPPH, FRAP, and Folin–Ciocalteu assays. A key objective was also to optimize data preprocessing parameters to improve the accuracy and robustness of metabolomic analyses. Multivariate analyses (PCA, OPLS-DA) effectively differentiated honey samples with high and low antioxidant potential. A total of 43 features were associated with increased antioxidant activity and about 30 compounds, including organic acids, free amino acids, and Amadori compounds—early Maillard reaction products—were identified. The amounts of most of these compounds exhibited strong positive correlation (r > 0.8) with measured antioxidant potential. These findings suggest that, in addition to polyphenols, other compound classes such as melanoidin precursors known as transition metal chelators significantly contribute to the antioxidant properties of buckwheat honey. This approach provides valuable insight into the bioactive composition of honey and supports the identification of potential antioxidant markers. Full article

One potential association that is gaining increasing attention is the link between multiple sclerosis (MS) and migraine, which are suggested to frequently coexist in young patients. This is the first study to analyze the levels of multiple markers of oxidative stress in sociodemographically similar groups of patients with migraine, MS, and both MS and migraine. A single cross-sectional study was conducted at the Department of Neurology, Rzeszów University. The study included 110 participants, comprising 26 healthy controls, 24 subjects with migraines, 30 with MS, and 30 with both MS and migraine. Oxidative stress markers were measured in patients’ serum. Patients with MS and migraines had statistically elevated levels of 3-nitrotyrosine, Amadori products, 4-hydroxy-nonenal, and oxidative damage to amino acids. Moreover, we observed reduced levels of thiol groups and total antioxidant capacity in the serum of patients with MS and migraines compared to healthy controls. The co-occurrence of migraines in MS leads to greater oxidative stress than MS alone. The impact of chronic oxidative stress on both MS and migraines may exacerbate symptoms and deteriorate the quality of life. Full article

Background: Italy’s plant biodiversity, characterized by many plant species, is an important source of bioactive secondary metabolites that help reduce the risk of the development of advanced glycation end product (AGE)-related diseases. AGEs are involved in various diseases, such as diabetes, cardiovascular, and neurodegenerative disorders. Therefore, the aim of the study was to investigate the antiglycative, hypoglycemic, and neuroprotective properties of nine edible plant extracts using different in vitro assays. Methods: The ability of the extracts to counteract AGE formation was evaluated at different stages of the glycation reaction using in vitro systems based on the determination of Amadori products and the co-incubation of a model protein with a dicarbonyl compound under different experimental conditions. In addition, the extracts’ methylglyoxal (MGO) and glyoxal (GO) trapping ability was investigated. Hypoglycemic activity was assessed by measuring α-amylase inhibition, while the neuroprotective effects were explored by testing amyloid β peptide 1-42 (Aβ1-42) fibrillogenesis inhibition. Results: All extracts generally had a dose-related capacity for the inhibition of AGE formation, mainly at the intermediate stage of the glycation reaction; high trapping capacity against MGO and GO; and promising hypoglycemic properties. In addition, they affected the fibrillogenesis process by reducing mature amyloid fibril formation and altering fibril morphology. Conclusions: All tested extracts had promising anti-fibrillogenic properties. Rosa canina extract was the most active among the tested plant species given its antiglycative activity (about 80% inhibition of AGE formation), trapping capacity against MGO and GO (almost 100%), hypoglycemic effects (66.20 ± 0.88%), and anti-fibrillogenic effects (69.00 ± 4.49% inhibition), indicating its suitability in the management of AGE-related diseases and for the potential development of a novel food ingredient. Full article

Parenteral nutrition (PN) is a nutrient solution administered intravenously (IV) to premature babies. PN causes elevations of some amino acids in blood samples that are also biomarkers used in newborn screening (NBS). Therefore, PN status must be annotated by clinicians on dried blood spot (DBS) cards to reduce NBS laboratory burdens associated with potential false results; however, NBS laboratories continue to receive DBSs with misannotated PN status. N-acetyltyrosine (NAT), a water-soluble tyrosine analog used to increase tyrosine bioavailability in PN solutions, can be used as a blood-based biomarker of PN administration in NBS assays. Residual DBS specimens and manufactured DBSs were used in analyses. The assay was developed and validated using flow injection analysis tandem mass spectrometry (FIA-MS/MS) for the detection of NAT. NAT was only present in neonate DBSs with annotated PN administration and was multiplexed into first-tier newborn screening assays. NAT was highly correlated with amino acids present in PN solutions, such as arginine, leucine, methionine, phenylalanine, and valine. In our sample cohort, we determined an NAT cutoff could aid the identification of misannotated neonates administered PN. We also report the Amadori rearrangement product valine–hexose (Val-Hex) was quantifiable in neonates administered PN, which we suspect forms in the PN solution and/or IV lines. Here, we present the first known use of NAT as a biomarker of PN administration, which is currently being piloted by two U.S. NBS laboratories. NAT and Val-Hex can aid the identification of misannotated DBSs from neonates administered PN, thus decreasing false positive rates. Full article

Honey differentiation based on the botanical origin is crucial to guarantee product authenticity, especially considering the increasing number of fraud cases. This study assessed the metabolomic differences arising from various botanical origins in honey products sold in Spanish markets, focusing on two goals: (1) discrimination within monofloral samples (eucalyptus, rosemary, and orange blossom honey) and (2) differentiation between multifloral vs. monofloral honey samples. An omics strategy based on ultra-high-performance liquid chromatography coupled with quadrupole-Orbitrap-high-resolution mass spectrometry (UHPLC-Q-Orbitrap-HRMS) was applied for the reliable identification of specific honey markers selected by orthogonal partial least squares discriminant analysis (OPLS-DA) (R²Y = 0.929–0.981 and Q² = 0.868–0.952), followed by the variable importance in projection (VIP) approach. Key amino acid, alkaloid, and trisaccharide markers were identified to distinguish between honey samples. Some Amadori compounds were highlighted as eucalyptus honey markers, suggesting their potential use for honey aging and botanical origin differentiation. L-phenylalanine and raffinose were markers of rosemary honey. Four markers (e.g., trigonelline, L-isoleucine, and N-(1-deoxy-1-fructosyl)isoleucine) were found in higher levels in multifloral samples, indicating a greater availability of amino acids, potentially increasing the Maillard reaction. This research is the first to address the botanical origin’s impact on honey by identifying novel markers not previously described. Full article

Abelmoschus manihot (L.) Medic flower (AMf) exhibits both nutritional value and bioactivities such as antioxidative, anti-inflammatory, neuroprotective, cardioprotective, and hepatoprotective effects. The aim of this investigation was to examine the potential impact of three different solvent extracts of AMf: supercritical CO₂ extraction extract, water extract, and ethanol extract (AME), on management of diabetes. All three extracts demonstrated significant inhibitory effects on α-glucosidase (IC₅₀ = 157–261 μg/mL) and lipase (IC₅₀ = 401–577 μg/mL) activities while enhancing the α-amylase activity (32.4–41.8 folds at 200 μg/mL). Moreover, all three extracts exhibited notable inhibition of the formation of advanced glycation end-products, including the Amadori products (inhibition rates = 15.7–36.6%) and the dicarbonyl compounds (inhibition rates = 18.6–28.3%). Among the three extracts, AME exhibited the most pronounced inhibitory effect. AME displayed substantial in vitro and intracellular antioxidative activity, and effectively reduced ROS production (135% at 500 μg/mL) in β-cells under hyperglycemic (HG) conditions. AME also enhanced the activity and gene expression of antioxidant enzymes, which were markedly decreased in the HG-induced β-cells. Furthermore, AME protected β-cell viability and maintained normal insulin secretion under HG conditions, likely due to its ability to reduce oxidative stress within β-cells. This study demonstrated the potential of AME in preventing and managing diabetes and its associated complications. Further in vivo research is necessary to thoroughly elucidate the preventive effects and their underlying mechanisms. Full article

Protein cysteine S-glycosylation is a relatively rare and less well characterized post-translational modification (PTM). Creating reliable model proteins that carry this modification is challenging. The lack of available models or natural S-glycosylated proteins significantly hampers the development of mass-spectrometry-based (MS-based) methodologies for detecting protein cysteine S-glycosylation in real-world proteomic studies. There is also limited MS-sequencing data describing it as easier to create synthetic S-glycopeptides. Here, we present the results of an in-depth manual analysis of automatically annotated CID/HCD spectra for model S-glucopeptides. The CID spectra show a long series of y/b-fragment ions with retained S-glucosylation, regardless of the dominant m/z signals corresponding to neutral loss of 1,2-anhydroglucose from the precursor ions. In addition, the spectra show signals manifesting glucosyl transfer from the cysteine position onto lysine, arginine (Lys, Arg) side chains, and a peptide N-terminus. Other spectral evidence indicates that the N-glucosylated initial products of transfer are converted into N-fructosylated (i.e., glycated) structures due to Amadori rearrangement. We discuss the peculiar transfer of the glucose oxocarbenium ion (Glc+) to positively charged guanidinium residue (ArgH+) and propose a mechanism for the gas-phase Amadori rearrangement involving a 1,2-hydride ion shift. Full article

Background: Histamine H2 receptor antagonists are a group of drugs that inhibit gastric juice secretion in gastrointestinal diseases. However, there is evidence to suggest that H2 blockers have a broader spectrum of activity. The antioxidant properties of H2 blockers have not been fully elucidated, and their anti-glycation potential has not been studied to date. Therefore, this is the first study to compare the antioxidant and antiglycation potentials of the most popular H2 antagonists (ranitidine, cimetidine, and famotidine) on protein glycoxidation in vitro. Methods: Bovine serum albumin (BSA) was glycated using sugars (glucose, fructose, galactose, and ribose) as well as aldehydes (glyoxal and methylglyoxal). Results: In the analyzed group of drugs, ranitidine was the only H2 blocker that significantly inhibited BSA glycation in all tested models. The contents of protein carbonyls, protein glycoxidation products (↓dityrosine, ↓N-formylkynurenine), and early (↓Amadori products) and late-stage (↓AGEs) protein glycation products decreased in samples of glycated BSA with the addition of ranitidine relative to BSA with the addition of the glycating agents. The anti-glycation potential of ranitidine was comparable to those of aminoguanidine and Trolox. In the molecular docking analysis, ranitidine was characterized by the lowest binding energy for BSA sites and could compete with protein amino groups for the addition of carbonyl groups. H2 blockers also scavenge free radicals. The strongest antioxidant properties are found in ranitidine, which additionally has the ability to bind transition metal ions. The systematic literature review also revealed that the anti-glycation effects of ranitidine could be attributed to its antioxidant properties. Conclusions: Ranitidine showed anti-glycation and antioxidant properties. Further research is needed, particularly in patients with diseases that promote protein glycation. Full article

Oxidative stress is believed to be a factor in the development and progression of renal cell carcinoma (RCC). The identification of the oxidative and nitrosative modification of proteins and the definition of their roles in clear cell RCC (ccRCC) may be helpful in the elaboration of targeted therapeutic approaches to mitigate protein damage. This study aimed to investigate the status of oxidative/nitrosative stress and to explore its role in the development and progression. The studied group consisted of 48 newly diagnosed ccRCC and 30 healthy controls. Serum levels of oxidative stress markers—advanced oxidation protein products (AOPP), thiol groups, Amadori reaction products, 3-nitrotyrosine, nitrate/nitrite, malondialdehyde (MDA), 4-hydroxy-2-nonenal and total antioxidant capacity (TAC)—were determined. Additionally, associations between tumour stage assessed according to TNM classification, histological grade, and the effect of the presence of angioinvasion on the level of stress markers were evaluated. The levels of Amadori products, 3-nitrotyrosine, and nitrate/nitrite were elevated, while the levels of thiol groups and TAC decreased in the ccRCC group. The levels of AOPP, Amadori, and 3-nitrotyrosine increased, and thiol groups and TAC levels decreased with the increasing pathological stage of the tumour. In the case of advanced histological assessment of the tumour, we found decreasing levels of thiol groups and increasing levels of MDA. In patients with angioinvasion, nitrate/nitrite and MDA levels were significantly elevated compared to those in patients without angioinvasion. Oxidative stress increased with the progression of the disease assessed according to the TNM and histological grade. These results demonstrate systemic oxidative stress in ccRCC, suggesting the therapeutic application of antioxidants. Full article

Imine or Schiff base formation is considered as a key event in the catalytic mechanisms of many enzymes and in certain biological transformations, including glycation. In this process, less stable amino-acid-derived Schiff bases rearrange into more stable ketoamines or Amadori products. Schiff bases are also stipulated to be stabilized through complexation with metal ions, or through intramolecular cyclization to form more stable and reversible cyclic isomers, such as oxazolidin-5-ones. These intermediates can be easily detected relative to Schiff bases due to their higher stability. In this study, high-resolution mass spectrometry and isotope labeling techniques were used to identify labile imines as their oxazolidin-5-one derivatives in heated reaction systems of glucose/alanine/FeCl₂, including their ¹³C-labeled counterparts. The reaction mixtures were heated for 2h at 110 °C and were analyzed by high resolution qTOF/MS for the presence of masses corresponding to Schiff bases of α-alanine with short chain aldehydes that can be generated from glucose degradation and also for the incorporation of ¹³C-labeled atoms from ¹³C-3 alanine and ¹³C-U glucose. Analysis of the data has indicated that Schiff bases can indeed be detected in the form of oxazolidin-3-ones, when methanol is used as the solvent. Furthermore, it was discovered that metal-ion-stabilized Schiff bases, in addition to forming oxazolidin-3-ones, can also undergo aldol addition with short chain sugars and initiate oligomerization reactions, leading to the formation of dimeric or trimeric oxazolidin-3-one oligomers, as demonstrated by their characteristic MS/MS fragmentations. Full article