Antioxidants

15 pages, 2012 KiB

Open AccessArticle

Food Grade Synthesis of Hetero-Coupled Biflavones and 3D-Quantitative Structure–Activity Relationship (QSAR) Modeling of Antioxidant Activity

by Hongling Zheng, Xin Yang, Qiuyu Zhang, Joanne Yi Hui Toy and Dejian Huang

Antioxidants 2025, 14(6), 742; https://doi.org/10.3390/antiox14060742 - 16 Jun 2025

Abstract

Biflavonoids are a unique subclass of dietary polyphenolic compounds known for their diverse bioactivities. Despite these benefits, these biflavonoids remain largely underexplored due to their limited natural availability and harsh conditions required for their synthesis, which restricts broader research and application in functional [...] Read more.

Biflavonoids are a unique subclass of dietary polyphenolic compounds known for their diverse bioactivities. Despite these benefits, these biflavonoids remain largely underexplored due to their limited natural availability and harsh conditions required for their synthesis, which restricts broader research and application in functional foods and nutraceuticals. To address this gap, we synthesized a library of rare biflavonoids using a radical–nucleophile coupling reaction previously reported by our group. The food grade coupling reaction under weakly alkaline water at room temperature led to isolation of 28 heterocoupled biflavones from 11 monomers, namely 3′,4′-dihydroxyflavone, 5,3′,4′-trihydroxyflavone, 6,3′,4′-trihydroxyflavone, 7,3′,4′-trihydroxyflavone, diosmetin, chrysin, acacetin, genistein, biochanin A, and wogonin. The structures of the dimers are characterized by nuclear magnetic resonance spectroscopy (NMR) and high-resolution mass spectroscopy (HRMS). In addition, we evaluated the antioxidant potential of these biflavones using a DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay and the DPPH value ranges between 0.75 to 1.82 mM of Trolox/mM of sample across the 28 synthesized dimers. Additionally, a three-dimensional quantitative structure–activity relationship (3D-QSAR) analysis was conducted to identify structural features associated with enhanced antioxidant activity. The partial least squares (PLS) regression QSAR model showed acceptable r² = 0.936 and q² = 0.869. Additionally, the average local ionization energy (ALIE), electrostatic potential (ESP), Fukui index (F-), and electron density (ED) were determined to identify the key structural moiety that was capable of donating electrons to neutralize reactive oxygen species. Full article

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42 pages, 18742 KiB

Open AccessArticle

Mitochondrial Unfolded Protein Response (mtUPR) Activation Improves Pathological Alterations in Cellular Models of Ethylmalonic Encephalopathy

by José Manuel Romero-Domínguez, Paula Cilleros-Holgado, David Gómez-Fernández, Rocío Piñero-Pérez, Diana Reche-López, Ana Romero-González, Mónica Álvarez-Córdoba, Alejandra López-Cabrera, Marta Castro De Oliveira, Andrés Rodríguez-Sacristán, Susana González-Granero, José Manuel García-Verdugo, Angeles Aroca and José A. Sánchez-Alcázar

Antioxidants 2025, 14(6), 741; https://doi.org/10.3390/antiox14060741 - 16 Jun 2025

Abstract

Ethylmalonic encephalopathy (EE) is a serious metabolic disorder that usually appears in early childhood development and the effects are seen primarily in the brain, gastrointestinal tract, and peripheral vessels. EE is caused by pathogenic variants in the gene that encodes the ETHE1 protein, [...] Read more.

Ethylmalonic encephalopathy (EE) is a serious metabolic disorder that usually appears in early childhood development and the effects are seen primarily in the brain, gastrointestinal tract, and peripheral vessels. EE is caused by pathogenic variants in the gene that encodes the ETHE1 protein, and its main features are high levels of acidic compounds in body fluids and decreased activity of the mitochondrial complex IV, which limits energy production in tissues that require a large supply of energy. ETHE1 is a mitochondrial sulfur dioxygenase that plays the role of hydrogen sulfide (H₂S) detoxification, and, when altered, it leads to the accumulation of this gaseous molecule due to its deficient elimination. In this article, we characterised the pathophysiology of ETHE1 deficiency in cellular models, fibroblasts, and induced neurons, derived from a patient with a homozygous pathogenic variant in ETHE1. Furthermore, we evaluated the effect of the activation of the mitochondrial unfolded protein response (mtUPR) on the mutant phenotype. Our results suggest that mutant fibroblasts have alterations in ETHE1 protein expression levels, associated with elevated levels of H₂S and protein persulfidation, mitochondrial dysfunction, iron/lipofuscin accumulation, and oxidative stress. We also identified a cocktail of compounds consisting of pterostilbene, nicotinamide, riboflavin, thiamine, biotin, lipoic acid, and L-carnitine that improved the cellular and metabolic alterations. The positive effect of the cocktail was dependent on sirtuin 3 activation (SIRT3) and was also confirmed in induced neurons obtained by direct reprogramming. In conclusion, personalised precision medicine in EE using patient-derived cellular models can be an interesting approach for the screening and evaluation of potential therapies. In addition, the activation of the SIRT3 axe of mtUPR is a promising therapeutic strategy for rescuing ETHE1 pathogenic variants. Full article

(This article belongs to the Special Issue Inhibition of Oxidative Stress and Related Signaling Pathways in Neuroprotection—2nd Edition)

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Graphical abstract

26 pages, 2049 KiB

Open AccessSystematic Review

Unlocking the Power of Magnesium: A Systematic Review and Meta-Analysis Regarding Its Role in Oxidative Stress and Inflammation

by Violeta Cepeda, Marina Ródenas-Munar, Silvia García, Cristina Bouzas and Josep A. Tur

Antioxidants 2025, 14(6), 740; https://doi.org/10.3390/antiox14060740 - 16 Jun 2025

Abstract

Magnesium plays a crucial role in over 300 enzymatic reactions related to energy production, muscle contraction, and nerve function. Given its essential biological functions and increasing prevalence of suboptimal intake, magnesium supplementation has gained attention for its potential health benefits, particularly in mitigating [...] Read more.

Magnesium plays a crucial role in over 300 enzymatic reactions related to energy production, muscle contraction, and nerve function. Given its essential biological functions and increasing prevalence of suboptimal intake, magnesium supplementation has gained attention for its potential health benefits, particularly in mitigating oxidative stress and inflammation. This systematic review and meta-analysis aimed to evaluate the antioxidant effects of dietary and supplemental magnesium on several biomarkers related to oxidative stress and inflammation. A systematic search of studies published from 2000 to 2025 identified 28 relevant articles, including both animal and human studies. The meta-analysis assessed the effects of magnesium supplementation on oxidative stress biomarkers such as nitric oxide (NO), total antioxidant capacity (TAC), malondialdehyde (MDA), glutathione (GSH), and C-reactive protein (CRP). While results showed a statistically significant reduction in CRP levels, suggesting an anti-inflammatory effect, no conclusive impact on oxidative stress biomarkers was observed. The findings highlight magnesium’s potential role in inflammation regulation, though its direct antioxidant effects remain uncertain. Further high-quality clinical trials are needed to clarify the impact of magnesium supplementation on oxidative stress and to explore its broader health implications. Full article

(This article belongs to the Section Health Outcomes of Antioxidants and Oxidative Stress)

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Graphical abstract

14 pages, 1282 KiB

Open AccessArticle

Serum 3-Nitrotyrosine in the Cardiovascular Disease of Patients with Systemic Lupus Erythematosus

by Juan C. Quevedo-Abeledo, Marta Hernández-Díaz, María García-González, Fuensanta Gómez-Bernal, Cristina Almeida-Santiago, Elena Heras-Recuero, Antonia de Vera-González, Alejandra González-Delgado, Pedro Abreu-González, Beatriz Tejera-Segura, Candelaria Martín-González, Miguel Á. González-Gay and Iván Ferraz-Amaro

Antioxidants 2025, 14(6), 739; https://doi.org/10.3390/antiox14060739 - 16 Jun 2025

Abstract

3-Nitrotyrosine (3-NT) is a product of tyrosine nitration mediated by reactive nitrogen species such as peroxynitrite anion and nitrogen dioxide. It serves as an indicator of inflammation, cell damage, and nitric oxide production. Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by [...] Read more.

3-Nitrotyrosine (3-NT) is a product of tyrosine nitration mediated by reactive nitrogen species such as peroxynitrite anion and nitrogen dioxide. It serves as an indicator of inflammation, cell damage, and nitric oxide production. Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by multisystem involvement and increased oxidative stress. Notably, cardiovascular (CV) disease has emerged as the leading cause of mortality among SLE patients. Our objective was to investigate the association between serum 3-NT levels and a wide range of disease characteristics in patients with SLE, with a particular emphasis on CV comorbidity. A total of 214 patients with SLE were enrolled. The serum levels of 3-NT as well as the activity (SLEDAI) and damage index (SLICC-SDI) scores, full lipid profile, insulin resistance indices, and carotid subclinical atherosclerosis were assessed. Multivariable linear regression analysis was carried out to study the relationship between 3-NT and clinical and laboratory disease characteristics, especially focusing on CV comorbidities. Except for body mass index, which showed a significant positive correlation, the demographic data and traditional CV risk factors did not correlate with 3-NT. After multivariable adjustments, several disease characteristics, including the disease duration, activity and damage indices, and autoantibody profile, showed significant positive associations with 3-NT. Regarding CV characteristics, several lipid profile molecules showed significant relationships with 3-NT. This was not the case for insulin resistance and subclinical atherosclerosis. Remarkably, patients with a high CV risk by SCORE2 showed higher 3-NT values compared to those with a low risk, although after the multivariable adjustment, this relationship was attenuated (but still showed a trend). In conclusion, serum 3-NT levels demonstrated significant positive correlations with multiple disease characteristics, including the disease activity and damage and the autoantibody profile. The lipid pattern in the SLE subjects also significantly and independently correlated with the 3-NT values. Our findings highlight the pathophysiological role of 3-NT specifically, and peroxidation in general, in patients with SLE. Full article

(This article belongs to the Special Issue Oxidative Stress in Cardiovascular Diseases (CVDs))

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18 pages, 3304 KiB

Open AccessArticle

Enhancement of Hypoxia Tolerance of Gibel Carp (Carassius auratus gibelio) via a Ferroporphyrin-Rich Diet

by Hualiang Liang, Haifeng Mi, Kai Wang, Mingchun Ren, Lu Zhang, Dongyu Huang and Jiaze Gu

Antioxidants 2025, 14(6), 738; https://doi.org/10.3390/antiox14060738 - 16 Jun 2025

Abstract

Gibel carp (Carassius auratus gibelio) were hypoxia stressed for 12 h after an 8-week FPR nutrient-enriched feeding experiment, which was to evaluate the role of FPR in hypoxic stress in gibel carp (Carassius auratus gibelio). The dissolved oxygen was [...] Read more.

Gibel carp (Carassius auratus gibelio) were hypoxia stressed for 12 h after an 8-week FPR nutrient-enriched feeding experiment, which was to evaluate the role of FPR in hypoxic stress in gibel carp (Carassius auratus gibelio). The dissolved oxygen was reduced to a range of 0.6 ± 0.2 mg/L. Results showed that FPR supplementation could maintain the osmotic pressure equilibrium by improving the ion concentrations of plasma including Na⁺, Ca⁺ and K⁺, and Na⁺/K⁺-ATPase activity of liver. FPR supplementation could effectively enhance the antioxidant capacity by improving the levels of GPX, SOD, CAT, and GSH, and reduce the level of MDA. FPR supplementation could improve the core gene expressions of Nrf2 signalling pathway including nrf2, sod, ho-1, gpx, and cat. The high levels of FPR supplementation (0.04%) might had a negative effect on immunity. FPR supplementation could improve the expression levels of HIF-1 signalling pathway-related genes to adapt to hypoxia condition including hif-1α, epo, angpt1, vegf, et1, and tfr-1. These results also were supported by higher SR and number of gill mitochondria in FPR supplementation. In general, the appropriate FPR supplementation was 0.01% based on the results of this study and economic cost, which could heighten hypoxic adaptation and SR. Full article

(This article belongs to the Special Issue Antioxidants Benefits in Aquaculture—3rd Edition)

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23 pages, 5946 KiB

Open AccessArticle

Inactivated Cells and Metabolites of Saccharomyces boulardii Alleviate Inflammation Damage in Caco-2 Monolayer Cells and Mice with Ulcerative Colitis

by Yuxin Jin, Zehui Niu, Menglin Feng, Huilian Che and Zhihong Liang

Antioxidants 2025, 14(6), 737; https://doi.org/10.3390/antiox14060737 - 16 Jun 2025

Abstract

Saccharomyces boulardii (S. boulardii) has attracted widespread attention due to its antimicrobial and anti-inflammatory properties. In this study, we prepared postbiotics from the heat-inactivated cells (HIC) and cell-free supernatant (CFS) of S. boulardii, with the important component L-arginine (Arg) from [...] Read more.

Saccharomyces boulardii (S. boulardii) has attracted widespread attention due to its antimicrobial and anti-inflammatory properties. In this study, we prepared postbiotics from the heat-inactivated cells (HIC) and cell-free supernatant (CFS) of S. boulardii, with the important component L-arginine (Arg) from the metabolic products included as one of the experimental groups. The results showed that in LPS-stimulated Caco-2 cells, HIC, CFS, and Arg protect intestinal epithelial barrier integrity by inhibiting the expression of TNF-α, IL-1β, and IL-6 while enhancing the expression of occludin and ZO-1 proteins. In dextran sulfate sodium (DSS)-induced colitis mice, HIC, CFS, and Arg alleviate symptoms such as weight loss and colonic damage while suppressing the upregulation of pro-inflammatory factors and the downregulation of tight junction proteins. Moreover, these postbiotics help restore the gut microbiota composition and functionality in colitis mice, with potentially superior regulatory effects compared to sulfasalazine (SASP). Overall, HIC and CFS protect the intestinal barrier function and improve DSS-induced colitis, supporting the development of functional food supplements. Full article

(This article belongs to the Topic Functional Food and Anti-Inflammatory Function)

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16 pages, 3742 KiB

Open AccessArticle

Redox Imbalance Is Associated with Neuronal Apoptosis in the Cortex of Neonates Gestated Under Chronic Hypoxia

by Esteban G. Figueroa, Rodrigo L. Castillo, Adolfo A. Paz, Matías Monsalves-Alvarez, Francisca Salas-Pérez, Ximena Calle, Tamara A. Jiménez, Emilio A. Herrera and Alejandro Gonzaléz-Candia

Antioxidants 2025, 14(6), 736; https://doi.org/10.3390/antiox14060736 - 15 Jun 2025

Abstract

Gestational chronic hypoxia impacts prenatal development, leading to fetal growth restriction (FGR), defined as the fetus’s failure to reach its genetic growth potential. Postnatal hypoxia in the cerebral tissue can induce a redox imbalance and mitochondrial dysfunction, consequently increasing neuronal death. However, these [...] Read more.

Gestational chronic hypoxia impacts prenatal development, leading to fetal growth restriction (FGR), defined as the fetus’s failure to reach its genetic growth potential. Postnatal hypoxia in the cerebral tissue can induce a redox imbalance and mitochondrial dysfunction, consequently increasing neuronal death. However, these data cannot necessarily be extrapolated to prenatal hypoxia. In this regard, this study aims to describe the effect of gestational hypoxia on redox balance and apoptosis cell death mechanisms in the prefrontal cortex of guinea pigs. Ten Guinea pig (Cavia porcellus) pregnant dams were utilized in this study; five gestated in normoxia (Nx; three newborn males, and two females) and five gestated under chronic hypobaric hypoxia (Hx; two newborn males, and three females). We monitored the pregnancies by ultrasound examinations from gestational days 20 to 65 (term ~ 70). At birth, pups were euthanized, and the fetal brain was collected for cellular redox measurement, mitochondrial enzyme expression, and apoptosis assay. Gestation under hypoxia induced an imbalance in the expression of anti- and pro-oxidant enzymes, resulting in increased oxidative stress. Additionally, a decrease in cytochrome I and III expression and neuronal density in the neonatal prefrontal cortex was observed. Finally, DNA fragmentation was increased by the TUNEL assay in the brain tissue of newborns gestated under chronic hypoxia. Our findings demonstrate the association of gestational hypoxia with oxidative stress and neuronal death in newborns, which may predispose to neuronal dysfunction in adulthood. Full article

(This article belongs to the Special Issue Oxidative Stress and Antioxidants in Hypoxia and Human Pathophysiology Settings, 2nd Edition)

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Graphical abstract

53 pages, 1497 KiB

Open AccessReview

Oxidative Stress and Inflammation: Drivers of Tumorigenesis and Therapeutic Opportunities

by Meimei Wang, Yaping Xiao, Jie Miao, Xin Zhang, Meng Liu, Longchao Zhu, Hongxin Liu, Xiaoyan Shen, Jihui Wang, Biao Xie and Di Wang

Antioxidants 2025, 14(6), 735; https://doi.org/10.3390/antiox14060735 - 15 Jun 2025

Abstract

As two pivotal regulatory factors in cancer biology, oxidative stress and inflammation interact dynamically through complex network mechanisms to influence tumor initiation, progression, and treatment resistance. Oxidative stress induces genomic instability, oncogenic signaling activation, and tumor microenvironment (TME) remodeling via the abnormal accumulation [...] Read more.

As two pivotal regulatory factors in cancer biology, oxidative stress and inflammation interact dynamically through complex network mechanisms to influence tumor initiation, progression, and treatment resistance. Oxidative stress induces genomic instability, oncogenic signaling activation, and tumor microenvironment (TME) remodeling via the abnormal accumulation of reactive oxygen species (ROS) or reactive nitrogen species (RNS). Conversely, inflammation sustains malignant phenotypes by releasing pro-inflammatory cytokines and chemokines and promoting immune cell infiltration. These processes create a vicious cycle via positive feedback loops whereby oxidative stress initiates inflammatory signaling, while the inflammatory milieu further amplifies ROS/RNS production, collectively promoting proliferation, migration, angiogenesis, drug resistance, and immune evasion in tumor cells. Moreover, their crosstalk modulates DNA damage repair, metabolic reprogramming, and drug efflux pump activity, significantly impacting the sensitivity of cancer cells to chemotherapy, radiotherapy, and targeted therapies. This review systematically discusses these advances and the molecular mechanisms underlying the interplay between oxidative stress and inflammation in cancer biology. It also explores their potential as diagnostic biomarkers and prognostic indicators and highlights novel therapeutic strategies targeting the oxidative stress–inflammation axis. The goal is to provide a theoretical framework and translational roadmap for developing synergistic anti-tumor therapies. Full article

(This article belongs to the Special Issue Oxidative Stress and Inflammation in Cancer Biology)

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27 pages, 2952 KiB

Open AccessArticle

Promising Dietary Supplements with Potential Senotherapeutic Effects: Aqueous Extracts from Enzymatically Hydrolysed Hemp Seed Cake Flour and Hemp Seed Protein Concentrate

by Anthea Miller, Inga Kwiecień, Marek Bednarski, Małgorzata Zygmunt, Jacek Sapa, Mateusz Sablik, Giorgia Pia Lombardo, Concetta Condurso, Maria Merlino and Magdalena Kotańska

Antioxidants 2025, 14(6), 734; https://doi.org/10.3390/antiox14060734 - 15 Jun 2025

Abstract

In the present study, the primary by-products of the hemp-seed oil process—hemp seed cake flour and hemp seed protein concentrate—underwent enzymatic hydrolysis using proteases and carbohydrases, either individually or in combination. The effectiveness of these enzymatic treatments in releasing bioactive compounds was evaluated [...] Read more.

In the present study, the primary by-products of the hemp-seed oil process—hemp seed cake flour and hemp seed protein concentrate—underwent enzymatic hydrolysis using proteases and carbohydrases, either individually or in combination. The effectiveness of these enzymatic treatments in releasing bioactive compounds was evaluated by assessing the antioxidant and anti-inflammatory properties of the aqueous extracts of both hydrolysed and untreated hemp by-products. The aim was to explore their potential senotherapeutic properties and promote their application as dietary supplements. Secondary metabolites such as flavonoids, phenolic acids, and catechins were analysed using high-performance liquid chromatography. Total phenolic, flavonoid, and protein contents were determined using spectrophotometric methods. Scavenging activity (2,2-Diphenyl-1-picrylhydrazyl scavenging assay (DPPH assay)), antioxidant power (Ferric reducing antioxidant power assay (FRAP assay)), and lipid peroxidation-reducing activity (thiobarbituric acid-reactive substance analysis) were assessed through in vitro assays. Possible anti-inflammatory effects were evaluated by assessing haemolysis inhibition. The impact of extracts on albumin glycation induced by exposure to fructose was also determined. To assess the toxicity of extracts, a zebrafish larvae model was employed. All extracts contained significant amounts of phenolic compounds, flavonoids, and proteins, and they exhibited notable activities in reducing lipid peroxidation and stabilising erythrocyte cell membranes. However, they did not significantly influence protein glycation (the glycation inhibition was only in the range of 15–40%). Our research demonstrates the substantial health-promoting potential, including senescence delay, of aqueous extracts from by-products of the hemp-seed oil process, which are available in large quantities and can serve as valuable supplements to support the health of animals, including humans, rather than being discarded as waste from oil production. Full article

(This article belongs to the Special Issue Natural Antioxidants and Their Oxidized Derivatives in Processed Food)

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17 pages, 675 KiB

Open AccessArticle

Evaluation of Bioactive Properties of Ultrasound-Assisted Extracts from Prokupac Grape Skins for Functional Foods

by Edina Avdović, Dušan Dimić, Đura Nakarada, Dušica Simijonović, Sandra Jovičić Milić, Katarina Marković, Mirjana Grujović, Marko Antonijević, Andrija Ćirić, Dejan Milenković and Zoran Marković

Antioxidants 2025, 14(6), 733; https://doi.org/10.3390/antiox14060733 - 15 Jun 2025

Abstract

The phenolic compounds present in wine industry by-products are a valuable source of biologically active ingredients that could be used in the development of functional foods. This manuscript investigates the potential of ultrasound-assisted extracts from Prokupac grape skins—a wine industry by-product—as functional food [...] Read more.

The phenolic compounds present in wine industry by-products are a valuable source of biologically active ingredients that could be used in the development of functional foods. This manuscript investigates the potential of ultrasound-assisted extracts from Prokupac grape skins—a wine industry by-product—as functional food ingredients. Four extracts were prepared using different solvents and evaluated for their antioxidant, anti-inflammatory, and antimicrobial properties. Antioxidant activity was assessed through DPPH, ABTS, and FRAP assays, as well as EPR spectroscopy. Phenolic composition was determined via HPLC analysis, and anti-inflammatory potential was evaluated using a lipoxygenase inhibition assay. Results indicated that the extracts PSE3 (ethyl acetate) and PSE0 (direct extraction with 50% ethanol) exhibited superior antioxidant and anti-inflammatory activities, which can be attributed to their high polyphenolic content. Additionally, the extracts demonstrated antimicrobial effects against the tested microorganisms. These findings suggest that Prokupac grape skin extracts, particularly PSE3 and PSE0, could be valuable additions to functional foods, offering health benefits through their bioactive properties. Full article

(This article belongs to the Section Natural and Synthetic Antioxidants)

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18 pages, 4187 KiB

Open AccessArticle

Lactobacillus fermentum ZC529 Protects Intestinal Epithelial Barrier Integrity by Activating the Keap1-Nrf2 Signaling Pathway and Inhibiting the NF-κB Signaling Pathway

by Zian Yuan, Lang Huang, Zhenguo Hu, Junhao Deng, Yehui Duan, Qian Jiang, Bi’e Tan, Xiaokang Ma, Chen Zhang and Xiongzhuo Tang

Antioxidants 2025, 14(6), 732; https://doi.org/10.3390/antiox14060732 - 14 Jun 2025

Abstract

The probiotic bacteria Lactobacillus fermentum ZC529 (L.f ZC529) has been identified from the colon of the Diannan small-ear (DSE) pig, but its intestinal protective function still lacks investigation. Here, we established a dextran sodium sulfate (DSS)-induced intestinal oxidative stress model in both [...] Read more.

The probiotic bacteria Lactobacillus fermentum ZC529 (L.f ZC529) has been identified from the colon of the Diannan small-ear (DSE) pig, but its intestinal protective function still lacks investigation. Here, we established a dextran sodium sulfate (DSS)-induced intestinal oxidative stress model in both Drosophila and porcine small intestinal epithelial (IPEC-J2) cell lines to explore the anti-oxidative and anti-inflammatory effects of L.f ZC529. The data showed that the intestinal colonization of L.f ZC529 counteracted DSS-induced intestinal oxidative stress and excessive reactive oxygen species (ROS) generation by activation of the CncC pathway, a homology of the nuclear factor erythroid 2-related factor 2 (Nrf2) in mammalian systems. Moreover, L.f ZC529 supplementation prevented flies from DSS-induced intestinal barrier damage, inflammation, abnormal excretory function, and shortened lifespan. Finally, L.f ZC529 also attenuated DSS-induced intestinal injury in the IPEC-J2 cell line by activating the Keap1-Nrf2 signaling and inhibiting the NF-κB signaling pathways. Together, this study unraveled the profound intestinal protective function of L.f ZC529 and provides its potential application as a new antioxidant in improving animal intestinal health as well as in developing a new probiotic in the food industry. Full article

(This article belongs to the Special Issue Natural Antioxidants in Animal Nutrition)

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29 pages, 1416 KiB

Open AccessReview

Restoring Glutathione Homeostasis in Glycation-Related Eye Diseases: Mechanistic Insights and Therapeutic Interventions Beyond VEGF Inhibition

by Yong Chool Boo

Antioxidants 2025, 14(6), 731; https://doi.org/10.3390/antiox14060731 - 14 Jun 2025

Abstract

Advanced glycation end-products (AGEs) and oxidative stress are recognized as central contributors to the pathogenesis of age-related or diabetic cataracts, diabetic retinopathy (DR), and age-related macular degeneration (AMD). These glycation-related diseases are characterized by impaired redox balance and decreased glutathione (GSH) levels. This [...] Read more.

Advanced glycation end-products (AGEs) and oxidative stress are recognized as central contributors to the pathogenesis of age-related or diabetic cataracts, diabetic retinopathy (DR), and age-related macular degeneration (AMD). These glycation-related diseases are characterized by impaired redox balance and decreased glutathione (GSH) levels. This review aims to examine the mechanistic links between AGEs and GSH depletion across ocular tissues by integrating in vitro, ex vivo, in vivo, and clinical studies relevant to this topic. The multiple levels of evidence highlight GSH homeostasis as both a biomarker and therapeutic target in glycation-related ocular disorders. Therapeutic strategies aimed at restoring GSH homeostasis under glycation stress are categorized into four mechanistic domains: (I) promoting GSH supply and synthesis, (II) enhancing GSH recycling, (III) mitigating glycation stress, and (IV) reducing oxidative and nitrosative stress. Most of these strategies have been explored via different approaches, and experimental findings with various interventions have shown promise in restoring GSH balance and mitigating AGE-induced damage. A pathological link between GSH depletion and vascular endothelial growth factor (VEGF) overexpression is observed in DR and wet AMD. GSH-centered interventions act upstream to modulate redox homeostasis while anti-VEGF therapies target downstream angiogenesis. This study supports the rationale for a dual-targeting strategy that combines redox-based interventions with VEGF inhibition in glycation-related ocular diseases. Full article

(This article belongs to the Special Issue Oxidative Stress in Eye Diseases)

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35 pages, 776 KiB

Open AccessReview

Pathways to the Brain: Impact of Fine Particulate Matter Components on the Central Nervous System

by Yasuhiro Ishihara, Miki Tanaka, Naoyuki Nezu, Nami Ishihara, Ami Oguro and Christoph F. A. Vogel

Antioxidants 2025, 14(6), 730; https://doi.org/10.3390/antiox14060730 - 14 Jun 2025

Abstract

Fine particulate matter with an aerodynamic diameter ≤ 2.5 µm (PM_2.5) has been extensively studied due to its adverse health effects. Most research has focused on its impact on the respiratory system; however, increasing attention is being directed toward its effects [...] Read more.

Fine particulate matter with an aerodynamic diameter ≤ 2.5 µm (PM_2.5) has been extensively studied due to its adverse health effects. Most research has focused on its impact on the respiratory system; however, increasing attention is being directed toward its effects on the brain. Associations between air pollution and neurological disorders—such as Alzheimer’s disease, cerebral infarction, and autism spectrum disorder—have been reported, with mechanism-based studies in animal models providing further insights. PM_2.5 comprises a complex mixture of thousands of chemical constituents. To elucidate its neurotoxicity mechanisms, it is essential to investigate both its transport pathways to the brain and the specific actions of its individual components. This review highlights key PM_2.5 components—water-soluble ions, metals, carbonaceous particles, polycyclic aromatic hydrocarbons, quinones, plastics, and bioaerosols—and outlines their potential routes of entry into the central nervous system, along with their associated mechanisms of action. By integrating these findings, this review contributes to a deeper understanding of the neurological effects mediated by PM_2.5, which represent one of the most critical aspects of its health impact. Full article

(This article belongs to the Section Health Outcomes of Antioxidants and Oxidative Stress)

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24 pages, 2342 KiB

Open AccessArticle

Topically Applied Molecular Hydrogen Normalizes Skin Parameters Associated with Oxidative Stress: A Pilot Study

by Natalia Debkowska, Marek Niczyporuk, Arkadiusz Surazynski and Katarzyna Wolosik

Antioxidants 2025, 14(6), 729; https://doi.org/10.3390/antiox14060729 - 14 Jun 2025

Abstract

Topical application of molecular hydrogen (H₂) has recently emerged as a promising strategy to counteract oxidative stress-related skin damage. This pilot clinical study aimed to assess the efficacy of hydrogen-rich water treatments in improving objective skin parameters in healthy adults. The [...] Read more.

Topical application of molecular hydrogen (H₂) has recently emerged as a promising strategy to counteract oxidative stress-related skin damage. This pilot clinical study aimed to assess the efficacy of hydrogen-rich water treatments in improving objective skin parameters in healthy adults. The hypothesis was that H₂, through its selective antioxidant and anti-inflammatory properties, would reduce oxidative stress, modulate inflammatory pathways, and enhance skin barrier integrity, leading to measurable improvements in skin appearance. Fifteen participants received topical treatments with hydrogen-rich water for four weeks. Skin parameters, including porphyrin levels, pigmentation irregularities, pore size, wrinkle severity, and biological skin age, were quantitatively assessed before and one week post-treatment. A statistically significant reduction in pore visibility was observed, particularly in younger participants. Although porphyrin levels showed a trend toward reduction, this change was not statistically significant. Improvements were also noted in pigmentation, wrinkle severity, and estimated biological skin age. The treatment was well tolerated, with no adverse effects reported. Despite promising outcomes, this study was limited by the absence of a control group and a relatively short follow-up period. Further controlled studies with larger sample sizes and molecular biomarker analyses are needed to confirm these effects and elucidate the underlying mechanisms. This study addresses a gap in the literature regarding standardized, clinical evaluation of topical H₂ application and highlights its potential for utilization in cosmetic and preventive dermatology. Full article

(This article belongs to the Special Issue Antioxidants for Skin Health)

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11 pages, 689 KiB

Open AccessArticle

Critical Evaluation and Validation of a High-Throughput Microplate-Based Cupric Reducing Antioxidant Capacity Method for the Analysis of Fish Feed Ingredients

by Aleksander Arnø, Viviana Sarmiento, Odd Elvebø and Pedro Araujo

Antioxidants 2025, 14(6), 728; https://doi.org/10.3390/antiox14060728 - 14 Jun 2025

Abstract

The cupric ion reducing antioxidant capacity (CUPRAC) assay, originally developed to measure the antioxidant capacity of nutritional products spectrophotometrically, utilized water as the solvent for Trolox. Due to the limited solubility of Trolox in aqueous solutions, the optimization of the solvent system was [...] Read more.

The cupric ion reducing antioxidant capacity (CUPRAC) assay, originally developed to measure the antioxidant capacity of nutritional products spectrophotometrically, utilized water as the solvent for Trolox. Due to the limited solubility of Trolox in aqueous solutions, the optimization of the solvent system was investigated to enhance analytical performance. Solvent combinations consisting of methanol, ethanol, and water were evaluated to identify the mixture that ensures complete dissolution and maximum absorbance signal, using a ternary plot diagram and mathematical modeling. A methanol/water ratio of 0.64:0.36 was identified as the optimal solvent composition. Under these conditions, the CUPRAC assay demonstrated a linear range of 0–50 μM, a limit of detection of 0.91 μM, and a limit of quantification of 2.75 μM. Precision, expressed as the coefficient of variation, was below 5%, and accuracy—defined as the deviation between nominal and back-calculated concentrations—remained within ±7.0%, in accordance with the variation range recommended by the International Committee on Harmonization. The estimated molar absorption coefficient at the optimized solvent ratio (ε_Trolox = 2.62 × 10⁴ L mol⁻¹ cm⁻¹) was applied to determine the antioxidant capacity of fish commercial feed ingredients containing a mixture of rosemary and olive extracts. Full article

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43 pages, 4992 KiB

Open AccessArticle

Restorative Effects of Synbiotics on Colonic Ultrastructure and Oxidative Stress in Dogs with Chronic Enteropathy

by Dipak Kumar Sahoo, Tracey Stewart, Emily M. Lindgreen, Bhakti Patel, Ashish Patel, Jigneshkumar N. Trivedi, Valerie Parker, Adam J. Rudinsky, Jenessa A. Winston, Agnes Bourgois-Mochel, Jonathan P. Mochel, Karin Allenspach, Romy M. Heilmann and Albert E. Jergens

Antioxidants 2025, 14(6), 727; https://doi.org/10.3390/antiox14060727 - 13 Jun 2025

Abstract

Synbiotics can be used to reduce intestinal inflammation and mitigate dysbiosis in dogs with chronic inflammatory enteropathy (CIE). Prior research has not assessed the colonic mucosal ultrastructure of dogs with active CIE treated with synbiotics, nor has it determined a possible association between [...] Read more.

Synbiotics can be used to reduce intestinal inflammation and mitigate dysbiosis in dogs with chronic inflammatory enteropathy (CIE). Prior research has not assessed the colonic mucosal ultrastructure of dogs with active CIE treated with synbiotics, nor has it determined a possible association between morphologic injury and signaling pathways. Twenty client-owned dogs diagnosed with CIE were randomized to receive either a hydrolyzed diet (placebo; PL) or a hydrolyzed diet supplemented with synbiotic-IgY (SYN) for 6 weeks. Endoscopic biopsies of the colon were obtained for histopathologic, ultrastructural, and molecular analyses and were compared before and after treatment. Using transmission electron microscopy (TEM), an analysis of the ultrastructural alterations in microvilli length (MVL), mitochondria (MITO), and rough endoplasmic reticulum (ER) was compared between treatment groups. To explore potential signaling pathways that might modulate MITO and ER stress, a transcriptomic analysis was also performed. The degree of mucosal ultrastructural pathology differed among individual dogs before and after treatment. Morphologic alterations in enterocytes, MVL, MITO, and ER were detected without significant differences between PL and SYN dogs prior to treatment. Notable changes in ultrastructural alterations were identified post-treatment, with SYN-treated dogs exhibiting significant improvement in MVL, MITO, and ER injury scores compared to PL-treated dogs. Transcriptomic profiling showed many pathways and key genes to be associated with MITO and ER injury. Multiple signaling pathways and their associated genes with protective effects, including fibroblast growth factor 2 (FGF2), fibroblast growth factor 7 (FGF7), fibroblast growth factor 10 (FGF10), synaptic Ras GTPase activating protein 1 (SynGAP1), RAS guanyl releasing protein 2 (RASGRP2), RAS guanyl releasing protein 3 (RASGRP3), thrombospondin 1 (THBS1), colony stimulating factor 1 (CSF1), colony stimulating factor 3 (CSF3), interleukin 21 receptor (IL21R), collagen type VI alpha 6 chain (COL6A6), ectodysplasin A receptor (EDAR), forkhead box P3 (FoxP3), follistatin (FST), gremlin 1 (GREM1), myocyte enhancer factor 2B (MEF2B), neuregulin 1 (NRG1), collagen type I alpha 1 chain (COL1A1), hepatocyte growth factor (HGF), 5-hydroxytryptamine receptor 7 (HTR7), and platelet derived growth factor receptor beta (PDGFR-β), were upregulated with SYN treatment. Differential gene expression was associated with improved MITO and ER ultrastructural integrity and a reduction in oxidative stress. Conversely, other genes, such as protein kinase cAMP-activated catalytic subunit beta (PRKACB), phospholipase A2 group XIIB (PLA2G12B), calmodulin 1 (CALM1), calmodulin 2 (CALM2), and interleukin-18 (IL18), which have harmful effects, were downregulated following SYN treatment. In dogs treated with PL, genes including PRKACB and CALM2 were upregulated, while other genes, such as FGF2, FGF10, SynGAP1, RASGRP2, RASGRP3, and IL21R, were downregulated. Dogs with CIE have colonic ultrastructural pathology at diagnosis, which improves following synbiotic treatment. Ultrastructural improvement is associated with an upregulation of protective genes and a downregulation of harmful genes that mediate their effects through multiple signaling pathways. Full article

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33 pages, 2687 KiB

Open AccessReview

Oxidized Low-Density Lipoprotein as a Potential Target for Enhancing Immune Checkpoint Inhibitor Therapy in Microsatellite-Stable Colorectal Cancer

by Xiaochun Zhang, Xiaorui Ye and Heiying Jin

Antioxidants 2025, 14(6), 726; https://doi.org/10.3390/antiox14060726 - 13 Jun 2025

Abstract

Oxidized low-density lipoprotein (oxLDL) exhibits differential expression in microsatellite-stable (MSS) and microsatellite instability-high (MSI) colorectal cancer (CRC), highlighting its potential therapeutic role in immune checkpoint inhibitor (ICI) resistance in MSS CRC. Elevated oxLDL levels in MSS CRC contribute to tumor progression and diminish [...] Read more.

Oxidized low-density lipoprotein (oxLDL) exhibits differential expression in microsatellite-stable (MSS) and microsatellite instability-high (MSI) colorectal cancer (CRC), highlighting its potential therapeutic role in immune checkpoint inhibitor (ICI) resistance in MSS CRC. Elevated oxLDL levels in MSS CRC contribute to tumor progression and diminish ICI efficacy by modulating metabolic reprogramming and immunosuppressive mechanisms within the tumor microenvironment (TME) by activating receptors such as LOX-1 and CD36. oxLDL triggers signaling pathways, including NF-κB, PI3K/Akt, and MAPK, leading to the expansion of immunosuppressive cells like regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), and M2 macrophages, while concurrently suppressing effector T cell functions. Additionally, oxLDL enhances oxidative stress and promotes fatty acid oxidation (FAO) and glycolytic metabolism, resulting in nutrient competition within the TME and establishing an immunosuppressive milieu, ultimately culminating in ICI resistance. This review systematically examines the disparities in oxLDL expression between MSS and MSI CRC and elucidates the molecular mechanisms through which oxLDL mediates ICI resistance. Furthermore, it explores potential therapeutic strategies targeting oxLDL, offering novel avenues to overcome immunotherapy resistance in MSS CRC. Full article

(This article belongs to the Special Issue Exploring Biomarkers of Oxidative Stress in Health and Disease)

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53 pages, 1156 KiB

Open AccessReview

Functional and Therapeutic Roles of Plant-Derived Antioxidants in Type 2 Diabetes Mellitus: Mechanisms, Challenges, and Considerations for Special Populations

by Vicente Javier Clemente-Suárez, Alexandra Martín-Rodríguez, Ana Isabel Beltrán-Velasco, Alejandro Rubio-Zarapuz, Ismael Martínez-Guardado, Roberto Valcárcel-Martín and José Francisco Tornero-Aguilera

Antioxidants 2025, 14(6), 725; https://doi.org/10.3390/antiox14060725 - 13 Jun 2025

Abstract

Background: Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by persistent hyperglycemia, oxidative stress, and inflammation, contributing to insulin resistance and long-term complications. Dietary antioxidants from plant sources, such as polyphenols, flavonoids, carotenoids, and phenolic acids, have been increasingly studied [...] Read more.

Background: Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by persistent hyperglycemia, oxidative stress, and inflammation, contributing to insulin resistance and long-term complications. Dietary antioxidants from plant sources, such as polyphenols, flavonoids, carotenoids, and phenolic acids, have been increasingly studied for their potential to modulate these pathophysiological mechanisms. Objective: This review aims to summarize and critically analyze the current evidence on the biological effects, therapeutic potential, and translational challenges of plant-derived antioxidants in the prevention and management of T2DM. Methods: This narrative review was conducted using peer-reviewed literature from PubMed, Scopus, and Web of Science. Emphasis was placed on mechanistic studies, clinical trials, bioavailability data, and advances in formulation technologies related to antioxidant compounds in the context of T2DM. Results: Plant antioxidants exert beneficial effects by modulating oxidative stress, reducing systemic inflammation, and improving insulin signaling pathways. However, their clinical application is limited by low bioavailability, chemical instability, and high interindividual variability. Recent developments, such as nanoencapsulation, synergistic functional food formulations, and microbiome-targeted strategies, have shown promise in enhancing efficacy. Additionally, personalized nutrition approaches and regulatory advances are emerging to support the integration of antioxidant-based interventions into diabetes care. Conclusions: Plant-derived antioxidants represent a promising complementary tool for T2DM management. Nonetheless, their effective clinical use depends on overcoming pharmacokinetic limitations and validating their long-term efficacy in well-designed trials. Integrating food technology, microbiome science, and precision nutrition will be crucial to translate these compounds into safe, scalable, and personalized therapeutic options for individuals with or at risk of T2DM. Full article

(This article belongs to the Special Issue Plant Antioxidants, Inflammation, and Chronic Disease)

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18 pages, 306 KiB

Open AccessReview

The Interplay Between Melatonin and Nitric Oxide: Mechanisms and Implications in Stroke Pathophysiology

by Santos Blanco, María del Mar Muñoz-Gallardo, Raquel Hernández and María Ángeles Peinado

Antioxidants 2025, 14(6), 724; https://doi.org/10.3390/antiox14060724 - 13 Jun 2025

Abstract

This work reviews the complex interplay between melatonin and nitric oxide (NO) in the central nervous system (CNS), with a detailed focus on its involvement in stroke pathophysiology. Melatonin, a neurohormone with potent antioxidant, anti-inflammatory, and neuroprotective properties, and NO, a gaseous signaling [...] Read more.

This work reviews the complex interplay between melatonin and nitric oxide (NO) in the central nervous system (CNS), with a detailed focus on its involvement in stroke pathophysiology. Melatonin, a neurohormone with potent antioxidant, anti-inflammatory, and neuroprotective properties, and NO, a gaseous signaling molecule with diverse roles, interact crucially. In the context of ischemic stroke, NO exhibits a dual role: it can be neuroprotective (primarily via endothelial nitric oxide synthase (eNOS)) or neurotoxic (especially through inducible nitric oxide synthase (iNOS) and neuronal nitric oxide synthase (nNOS), contributing to the formation of damaging peroxynitrite (ONOO⁻)). Melatonin has consistently demonstrated neuroprotective effects in animal models of stroke. Its key mechanisms related to NO include (1) differential modulation of nitric oxide synthase isoforms, suppressing detrimental iNOS expression/activity while often preserving or enhancing beneficial eNOS; (2) direct scavenging of NO and, critically, highly reactive peroxynitrite, thereby attenuating nitrosative stress; (3) reduction in neuroinflammation, partly by promoting M2 (anti-inflammatory) microglia polarization; and (4) mitochondrial protection and decreased apoptosis. These multifaceted actions of melatonin contribute to reduced infarct volume and improved functional outcomes, underscoring its considerable therapeutic potential for ischemic stroke through the favorable modulation of the melatonin–NO axis. Full article

(This article belongs to the Special Issue Free-Radical Scavenging and Antioxidant Properties of Melatonin, 2nd Edition)

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