Search Results (180)

Oxidative stress significantly contributes to the exacerbation of brain damage during cerebral ischemia-reperfusion injury (CIR/I). In our previous study, purified cornel iridoid glycoside (PCIG), consisting of morroniside (MOR) and loganin (LOG), showed neuroprotective effects against CIR/I. To further explore the antioxidative effects and underlying molecular mechanisms, we applied PCIG, MOR, and LOG to rats injured by middle cerebral artery occlusion/reperfusion (MCAO/R) as well as H₂O₂-stimulated PC12 cells. Additionally, the molecular docking analysis was performed to assess the interaction between the PCIG constituents and Kelch-like ECH-associated protein 1 (Keap1). The results showed that the treated rats experienced fewer neurological deficits, reduced lesion volumes, and lower cell death accompanied by decreased levels of malondialdehyde (MDA) and protein carbonyl, as well as increased activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). In H₂O₂-stimulated PC12 cells, the treatments decreased reactive oxygen species (ROS) production, mitigated mitochondrial dysfunction, and inhibited mitochondrial-dependent apoptosis. Moreover, the treatments facilitated Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) translocation into the nucleus and selectively increased the expression of NAD(P)H quinone oxidoreductase 1 (NQO-1) and heme oxygenase 1 (HO-1) through MOR and LOG, respectively. Both MOR and LOG demonstrated strong binding affinity to Keap1. These findings suggested that PCIG, rather than any individual components, might serve as a valuable treatment for ischemic stroke by activating the Nrf2/NQO-1 and Nrf2/HO-1 signaling pathway. Full article

This study was conducted through in vivo and in vitro experiments and aimed to reveal the regulatory effect of water extract of Artemisia annua L. (WEAA) on the antioxidant function of mutton sheep and the underlying mechanism. In the in vivo experiment, 32 Dorper × Han female sheep (3 months old; avg. body weight: 24 ± 0.09 kg) were allocated to four groups (eight lambs/group) and fed a diet containing 0, 500, 1000, and 1500 mg/kg WEAA, respectively. In the in vitro experiments, peripheral blood lymphocytes (PBLs) were cultured with different doses of WEAA (0, 25, 50, 100, 200, 400 µg/mL) to determine the optimal concentration, followed by a 2 × 2 factorial experiment with four treatment groups (six replicates per treatment group): the ML385(−)/WEAA(−) group, the ML385(−)/WEAA(+) group, the ML385(+)/WEAA(−) group, and the ML385(+)/WEAA(+) group. The results showed that WEAA supplementation dose-dependently increased serum, liver and spleen tissue total antioxidant capacity, glutathione peroxidase (GSH-Px), and catalase (CAT) activity while reducing malondialdehyde level (p < 0.05). Moreover, WEAA supplementation significantly upregulated the liver and spleen expression of nuclear factor erythroid 2-related factor 2, superoxide dismutase 2, GSH-Px, CAT and NAD(P)H quinone dehydrogenase 1 (p < 0.05) while significantly downregulating the kelch-like ECH associated protein 1 expression in a dose-dependent manner (p < 0.05), thereby activating the Keap1/Nrf2 pathway with the peak effect observed in the 1000 mg/kg WEAA group. Additionally, supplementation with 100 µg/mL of WEAA had significant antioxidation activity in the culture medium of PBLs. Its action mechanism involved the Keap1/Nrf2 pathway; specifically, WEAA exerted its antioxidant effect by upregulating the gene expression related to the Keap1/Nrf2 pathway. In conclusion, WEAA enhances sheep’s antioxidant capacity by up-regulating Keap1/Nrf2 pathway genes and boosting antioxidant enzyme activity. The results provided experimental support for the potential application of WEAA in intensive mutton sheep farming. Full article

This study evaluated the inhibitory activity of quercetin at sub-inhibitory concentrations on quorum-sensing (QS) molecules in vitro and the effects of dietary supplementation with quercetin (for 24 consecutive days) on enterotoxigenic Escherichia coli (ETEC)-induced inflammatory and oxidative stress responses in weaned piglets. The piglets were fed one of three diets: the basal diet (Con), ETEC challenge (K88) after the basal diet, or ETEC challenge (quercetin + K88) after the basal diet supplemented with 0.2% quercetin. In vitro experiments revealed that 5 mg/mL quercetin exhibited the strongest QS inhibitory activity and reduced pigment production by Chromobacterium violaceum ATCC12472 by 67.70%. In vivo experiments revealed that quercetin + K88 significantly increased immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG) levels in the serum, ileum mucosa, and colon mucosa; increased glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD) levels in the serum, liver, and colon mucosa; and decreased cluster of differentiation 3 (CD3) and cluster of differentiation 8 (CD8)activity in the serum compared with K88 alone. Quercetin + K88 significantly alleviated pathological damage to the liver and spleen and upregulated antioxidant genes (nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1(HO-1), CAT, SOD, and glutathione s-transferase (GST)). Inducible nitric oxide synthase (iNOS) and kelch-like ech-associated protein 1 (Keap1), which cause oxidative damage to the liver and spleen, were significantly downregulated. The acetic acid content in the cecum was significantly increased, and the E. coli count and QS signal molecule autoinducer-2 (AI-2) yield were significantly reduced. In conclusion, 0.2% dietary quercetin can alleviate ETEC-induced inflammation and oxidative stress in weaned piglets. Full article

Liver fibrosis remains a critical health concern with limited therapeutic options. Kaempferol (Kae) is a natural flavonoid widely present in natural plants, yet its role in modulating gut–liver axis interactions during fibrosis is unexplored. This study investigates the hepatoprotective effects of Kae on alleviating carbon tetrachloride (CCl₄)-induced liver fibrosis, and its underlying mechanisms, focusing on oxidative stress, gut microbiota, and short-chain fatty acids (SCFAs), are revealed. A mouse model of hepatic fibrosis was built by the subcutaneous injection of CCl₄. Meanwhile, Kae was administered by gavage at doses of 25, 50, and 100 mg/kg body weight. Serum biomarkers, liver histopathology, oxidative damage markers, and nuclear factor erythroid 2-related factor 2 (Nrf2)/kelch-like ECH-associated protein 1 (Keap1)/heme oxygenase 1 (HO-1) signaling were analyzed. AML12 hepatocytes were pretreated with Kae or SCFAs (acetate, propionate, butyrate) before H₂O₂-induced oxidative injury. The changes in gut microbiota and the levels of SCFAs were assessed via 16S rRNA sequencing and GC-MS, respectively. Kae effectively alleviated the destruction of the liver morphology and tissue structure, reduced the infiltration of inflammatory cells, collagen deposition in the liver, and the expression of fibrotic factors, and downregulated the oxidative stress level in the liver of mice with liver fibrosis by activating the Nrf2/Keap1/HO-1 pathway (p < 0.05 or 0.01). In vitro, Kae significantly mitigated H₂O₂-induced cytotoxicity and oxidative damage (p < 0.05 or 0.01). Furthermore, Kae restored gut microbiota diversity, increased beneficial genera (e.g., Lactobacillus), and elevated both intestinal and hepatic SCFA levels (p < 0.01). The discrepant SCFA pretreatment similarly protected AML12 cells by activating Nrf2 signaling (p < 0.05 or 0.01). Our research suggests that Kae could inhibit CCl₄-induced liver fibrosis by restoring the levels of intestinal metabolite SCFAs to reduce oxidative damage. Full article

: Negative energy balance (NEB) in dairy cows induces excessive lipolysis, leading to elevated levels of β-hydroxybutyric acid (BHBA), which, when accumulated, can cause liver damage. Rutin (RT), a natural flavonoid with antioxidant and anti-inflammatory properties, has demonstrated potential hepatoprotective effects; however, its ability to mitigate BHBA-induced hepatocellular injury in calves remains unclear. This study first assessed the impact of various BHBA concentrations on oxidative stress in calf hepatocytes, then explored the protective effects and underlying mechanisms of RT, and finally employed untargeted metabolomics to further elucidate RT’s mode of action. The results showed that exposure to 1.2 mM BHBA significantly increased malondialdehyde (MDA), nitric oxide (NO) contents, and reactive oxygen species (ROS) levels, while markedly decreasing glutathione (GSH) content and catalase (CAT) activity compared with the blank control. Notably, pretreatment with 100 μg/mL RT resulted in the greatest increase in GSH contents (180%) compared to BHBA treatment alone, while 150 μg/mL RT led to the most pronounced reduction in MDA contents (220%). Furthermore, BHBA treatment significantly upregulated the expression of Kelch-like ECH-associated protein 1 (Keap1) and downregulated nuclear factor erythroid 2-related factor 2 (Nrf2), NAD(P)H quinone dehydrogenase 1 (NQO1), and heme oxygenase-1 (HO-1) at both the mRNA and protein levels. These alterations were effectively reversed by pretreatment with 100 μg/mL RT. Non-targeted metabolomics identified 1525 metabolites in total. Based on OPLS-DA, metabolites with a variable importance in projection (VIP) > 1 and p < 0.05 were considered significantly altered. Compared with the blank control, BHBA treatment upregulated 47 metabolites—including 8-hydroxy-2′-deoxyguanosine, 3-hydroxyisovaleric acid, and N-palmitoyl-sphingosine—and downregulated 58 metabolites, such as betaine, linolenic acid, and arachidonic acid. In contrast, RT pretreatment upregulated 207 metabolites relative to the BHBA treatment, including linolenic acid, taurocholic acid, and 4-hydroxybenzoic acid, and downregulated 126 metabolites, including 3-hydroxyisovaleric acid, 8-hydroxy-2′-deoxyguanosine, and pyruvaldehyde. Pathway enrichment analysis indicated that RT alleviated BHBA-induced hepatocyte injury primarily by modulating the fatty acid degradation pathway. In summary, RT mitigated BHBA-induced oxidative stress in calf hepatocytes by regulating the Keap1/Nrf2 signaling pathway and further exerted protective effects through metabolic reprogramming. Full article

Fish oil’s neuroprotective effects in ethanol-induced liver injury was investigated through the factor 2 (NRF2)/Kelch-like ECH-associated protein 1 (KEAP1) pathway. Male Wistar rats received a control liquid diet (C) or an ethanol diet (E), with 25% or 57% of fat replaced by fish oil (CF25, CF57, EF25, EF57) for 8 weeks. Compared to the C group, the E group exhibited brain damage, including impaired performance of Y maze and novel object recognition test, increased glial fibrillary acidic protein (GFAP)-positive astrocytes, and ionized calcium-binding adapter molecule 1 (Iba-1)-positive microglia. In the prefrontal cortex, glutathione (GSH) and phosphorylated (p)-NRF2 decreased, catalase activity increased, and nqo1 mRNA declined; hippocampal NRF2 and nqo1 were also downregulated. However, compared to the E group, the EF25 and EF57 groups exhibited restored spatial and memory functions, reduced GFAP and Iba-1 expressions, potentiated β-amyloid (Aβ) clearance, and escalated catalase activity. Furthermore, increases in p-NRF2 and elevated hippocampal nqo1 mRNA expressions in the prefrontal cortex were observed in the EF25 and EF57 groups. In conclusion, fish oil ameliorated deficits in spatial and memory functions, and enhanced Aβ1-42 clearance in the prefrontal cortex and hippocampus of rats with chronic ethanol-induced liver damage by activating the NRF2/KEAP1 pathway. Full article

Hyperuricemia (HUA) is a metabolic disease caused by disrupted purine metabolism, characterized by abnormally elevated uric acid (UA) levels. Stachydrine, an alkaloid in natural foods, exhibits multiple biological activities. This study aimed to evaluate the effects of stachydrine on alleviating HUA. An HUA mouse model was established through high-nucleoside diet induction, and stachydrine’s effects on UA levels and renal injury were investigated. Our findings revealed that stachydrine enhanced uric acid excretion by upregulating ATP-binding cassette subfamily G member 2 (ABCG2). Furthermore, stachydrine mitigated HUA-induced renal inflammation, mitochondrial oxidative stress and apoptosis. Mechanistically, stachydrine facilitated the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) by downregulating Kelch-like ECH-associated protein 1 (Keap1), subsequently activating the Keap1/Nrf2 signaling pathway and alleviating local oxidative stress. This study demonstrated the UA-lowering and renoprotective effects of stachydrine, suggesting its potential as a functional food ingredient for mitigating HUA. Full article

Using a multidisciplinary approach, this paper was designed to prepare, identify, and characterize novel maize antioxidant cyclic peptides from protein hydrolysate of corn gluten meal (CGM). A bioinformatics approach was used to identify the best protease, and the results showed that papain+subtilisin was most likely to produce antioxidant cyclic peptides. The result of the enzymatic hydrolysis validation experiment showed that hydrolysate by papain+subtilisin yielded the highest concentration of cyclic peptide (67.14 ± 1.88%) and remarkable DPPH, ABTS, and hydroxyl radical scavenging rates (81.06 ± 2.23%, 82.82 ± 1.83%, and 47.44 ± 2.43%, respectively) compared to other hydrolysates. Eleven antioxidant cyclic peptides were identified in the protein hydrolysate of CGM through sequential purification and mass spectrometry analysis. The results of molecular docking analysis indicated that the cyclic peptides can form stable hydrogen bonds and hydrophobic interactions with the key amino acid residues of Kelch-like ECH-associated protein 1 (Keap1). Cyclic peptides may regulate the Keap1-Nrf2 pathway by occupying the Kelch domain of Keap1, inhibiting the ubiquitination degradation of Nrf2 (nuclear factor erythroid 2-related factor 2), thereby stabilizing the Nrf2 protein and activating the antioxidant gene network. This study underlined the bioinformatics approach for antioxidant cyclic peptide discovery, which is time- and cost-effective and promotes new cyclic peptide drugs or functional food development. Full article

The Warburg effect, a unique glycolytic phenomenon in cancer cells, presents a promising target for developing selective anticancer agents. Previously, BH10, a hit compound disrupting glycolytic metabolism, was identified via phenotypic screening, with Kelch-like ECH-associated protein 1 (Keap1) proposed as a potential target. To enhance its potency and selectivity, a library of BH10-derived salt compounds was synthesized. Among these, 7b exhibited nanomolar anticancer activity (IC₅₀ = 22.97 nM) and a high selectivity ratio (IC₅₀ of non-cancerous cells/IC₅₀ of cancer cells = 41.43). Molecular docking revealed that all naphthoimidazole salt analogues (7a–f) bind to Keap1 via carbonyl-mediated interactions, with variations in hydrogen-bonding residues (e.g., VAL606, ILE559). Full article

Chronic oxidative distress results in cellular damage, necessitating adaptive mechanisms for redox balance. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) is pivotal in the regulation of key antioxidant and cytoprotective genes. Under normal conditions, Nrf2 undergoes rapid degradation through polyubiquitination. However, it can be activated during oxidative eustress and distress via modifications of its inhibitor Kelch-like ECH-associated protein 1 (KEAP1). Activation of the Nrf2-Keap1 signaling pathway may decelerate aging-related muscle degeneration, such as sarcopenia and cachexia. In this study, we investigated the efficacy of two muscle-active endogenous factors, creatine and L-β-aminoisobutyric acid (L-BAIBA), as well as two natural phytochemicals, luteolin and silibinin, to induce Nrf2 in the murine myoblast cell line C2C12. Our results revealed that only luteolin significantly enhances Nrf2 activity in both proliferating and differentiated C2C12 cells, leading to increased expression of Nrf2 target genes in proliferating C2C12 cells. In contrast, the other three compounds had either no or only minor effects on Nrf2 activity or target gene expression. Our results underscore the distinct responses of C2C12 cells to different Nrf2 activators, emphasizing the significance of cellular context in their biological effects and highlight luteolin as a potential future treatment option to counteract muscle wasting associated with sarcopenia and cachexia. Full article

The intestine is an important immune organ of aquatic animals and it plays an essential role in maintaining body health and anti-oxidative stress. To investigate the toxic effects of deltamethrin in intestinal tissue of Chinese mitten crabs (Eriocheir sinensis), 120 healthy crabs were randomly divided into two experimental groups (blank control group and deltamethrin-treated group), with three replicates in each group. After being treated with deltamethrin for 24 h, 48 h, 72 h, and 96 h, intestinal tissues were collected aseptically to assess the effects of deltamethrin on oxidative stress, immunity, apoptosis-related genes, and the structure of microflora in intestinal tissues. Additionally, correlations between gut microbiota composition and intestinal tissue damage-associated genes were analyzed. The results demonstrated that prolonged exposure to deltamethrin induced oxidative stress damage in intestinal tissue. Compared with the blank control group, the expression of autophagy-related genes B-cell lymphoma/Leukemia-2 (bcl-2), c-Jun N-terminal kinase (jnk), Microtuble-associated protein light chain 3 (lc3c), Cysteine-dependent Aspartate-specific Protease 8 (caspase 8), BECN1(beclin1), oxidative stress damage-related genes MAS1 proto-oncogene (mas), Glutathione Peroxidase (gpx), kelch-like ECH-associated protein 1 (keap1), Sequestosome 1 (p62), Interleukin-6 (il-6), and immune-related genes Lipopolysaccharide-induced TNF-alpha Factor (litaf), Heat shock protein 90 (hsp90) and prophenoloxidase (propo) in the deltamethrin treatment group were significantly up-regulated at 96 h (p < 0.05 or p < 0.01). Additionally, 16S rRNA sequencing showed that the diversity of intestinal flora in the deltamethrin-treated group was significantly higher compared with the blank control group (p < 0.01). Analysis of the differences in the composition of intestinal flora at the genus level showed that the relative abundance of Candidatus Bacilloplasma in the deltamethrin treatment group was significantly lower than that in the blank control group (p < 0.01). In contrast, the relative abundances of Flavobacterium, Lachnospiraceae_NK4A136_group, Acinetobacter, Chryseobacterium, Lacihabitans, Taibaiella, Hydrogenophaga, Acidovorax, and Undibacterium were significantly higher than those in the blank control group (p < 0.05 or p < 0.01). Pearson correlation analysis revealed that Malaciobacter, Shewanella, and Prevotella exhibited significant positive correlations with gene indicators (jnk, gpx, lc3c, litaf, hsp90), while Dysgonomonas, Vibrio, and Flavobacterium demonstrated significant negative correlations with multiple gene indicators (caspase 8, p62, il-16, keap1, jnk, etc). These results demonstrate that deltamethrin significantly impacts the gut microbiota, immune function, and antioxidant capacity of E. sinensis. The changes in gut microbiota have correlations with the biomarkers of intestinal tissue injury genes, indicating that gut microbiota plays a crucial role in deltamethrin-induced intestinal tissue damage. These insights contribute to a better understanding of the ecological risks associated with deltamethrin exposure in aquatic organisms. Full article

The transcription factor erythroid 2-related factor 2 (Nrf2) is a central regulator of cellular defense mechanisms against oxidative stress and inflammation. Keap1 (Kelch-like ECH-associated protein 1) regulates Nrf2 activity by ubiquitination-mediated cytoplasmic retention, thereby suppressing its nuclear translocation and subsequent transcriptional activation of genes encoding phase II detoxifying enzymes. Using a structure-based virtual screening approach, we screened ~16,000 natural compounds to identify Keap1-Nrf2 PPI inhibitors. Nine compounds were identified based on their high binding affinities and favorable interactions with Keap1, primarily through non-covalent interactions. To validate the binding stability of these inhibitors, molecular dynamics (MD) simulations were performed, confirming the robustness of the Keap1–inhibitor complexes over time. Subsequent in vitro assays on human epithelial keratinocyte cells (HaCaT) revealed that six of these compounds notably upregulated Nrf2 mRNA expression, regis tering increases from 23% to 50% in comparison to the control. Notably, chebulinic acid emerged as the most potent compound, demonstrating the greatest elevation in Nrf2 expression. Penetration studies further showed that chebulinic acid, when encapsulated in silk fibroin, achieved a 0.14% penetration rate after 24 h though it could not penetrate into the stratum corneum alone. This result highlighted the potential of chebulinic acid in the use of anti-aging skincare formulations. Collectively, our findings affirmed that molecular docking is a reliable and effective approach for the identification of novel anti-aging agents targeting the Keap1-Nrf2 pathway. Full article

Intestinal stem cells (ISCs) maintain epithelial renewal through their proliferation and differentiation capabilities, responding to various intestinal insults. However, the impact of iturin A, a natural antimicrobial peptide, on ISC viability and its potential to mitigate heat-stable enterotoxin b (STb)-induced intestinal damage remains unclear. Our recent study demonstrated that oral administration of iturin A enhances tight junction protein expression, accelerates crypt-villus regeneration, and restores epithelial barrier integrity in STb-exposed mice. Furthermore, iturin A promotes ISC proliferation and differentiation, significantly increasing the numbers of goblet and Paneth cells in the jejunum following STb exposure. Notably, iturin A regulates intestinal homeostasis by scavenging reactive oxygen species (ROS), while elevating total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) levels in both serum and jejunal mucosa. Mechanistically, iturin A facilitates nuclear factor-erythroid 2- related factor 2 (Nrf2) release by disrupting Kelch-like ECH-associated protein 1 (Keap1), leading to the upregulation of the antioxidant enzyme glutathione peroxidase 4 (GPX4). In conclusion, our findings indicate that iturin A alleviates oxidative stress induced by STb through modulation of the Keap1/Nrf2 pathway and promotes ISC differentiation into goblet and Paneth cells, thereby enhancing resistance to STb-induced damage. Full article

Oxidative stress, a pivotal driver of neurodegenerative diseases, results from an imbalance between the generation of reactive oxygen species (ROS) and cellular antioxidant defenses. This review provides a comprehensive analysis of key oxidative stress sources, focusing on NADPH oxidase (NOX) hyperactivity and mitochondrial Uncoupling Protein (UCP) downregulation. Critically, we examine the therapeutic potential of phytochemicals in mitigating NOX-mediated ROS generation through direct enzyme inhibition, including impacts on NOX subunit assembly and gene expression. Furthermore, we explore the ability of phytochemicals to bolster cellular antioxidant defenses by activating the Kelch-like ECH-associated protein 1 (KEAP1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway, elucidating the upregulation of antioxidant genes, such as GPx, SOD, CAT, and HO-1. This review expands beyond confined overviews; emphasizes specific molecular interactions between phytochemicals and target proteins, including NOX isoforms; and provides an in-depth analysis of the specific antioxidant genes upregulated via Nrf2. This approach aims to pave the way for targeted and translatable therapeutic strategies in neurodegenerative diseases. Ultimately, this review illuminates the intricate molecular dynamics of oxidative stress in neurodegenerative diseases; underscores the potential of phytochemicals to restore redox homeostasis and reverse pathological conditions through precise modulation of key signaling pathways. Full article

Objectives: Ischemic stroke is a severe neurological disorder with high morbidity, mortality, and disability rates, posing a substantial burden on patients, families, and healthcare systems. Soy isoflavone (SI), a naturally occurring phytoestrogen, has demonstrated promising neuroprotective effects. This study aimed to evaluate the anti-stroke efficacy of SI and elucidate its underlying mechanisms through integrated phytochemical profiling, network pharmacology, and both in vitro and in vivo experimental validation. Methods: Active constituents of SI were extracted via reflux and identified using liquid chromatography–mass spectrometry (LC-MS). Network pharmacology was employed to predict therapeutic targets and signaling pathways. The neuroprotective effects of SI were first assessed in PC12 cells subjected to oxygen–glucose deprivation/reoxygenation (OGD/R) injury in vitro. For in vivo evaluation, transient cerebral ischemia–reperfusion injury was induced using the bilateral common carotid artery occlusion (BCCAO) model in adult male ICR rats (27.3 ± 1.8 g; 6–8 weeks old), obtained from the Shanghai Experimental Animal Center, Chinese Academy of Sciences. Forty-eight rats were randomly assigned into four groups (n = 12): sham, model (BCCAO), SI-treated (100 mg/kg, oral gavage for 5 days), and edaravone (EDA)-treated (10 mg/kg, i.p., positive control). All procedures were approved by the Institutional Animal Care and Use Committee of Changchun Normal University (Approval No. 2024003, 13 March 2024) and conducted in accordance with the NIH guidelines and ARRIVE 2.0 reporting standards. Results: In vitro, SI significantly enhanced PC12 cell viability from 57.23 ± 2.88% to 80.76 ± 4.43% following OGD/R. It also reduced intracellular Ca²⁺ by 58.42%, lactate dehydrogenase (LDH) release by 37.67%, caspase-3 activity by 55.05%, and reactive oxygen species (ROS) levels by 74.13% (p < 0.05). A flow cytometry analysis revealed that OGD/R increased the apoptosis rate from 5.34% (control) to 30.85% (model group), which was significantly attenuated by SI treatment, especially in the 560 µg/mL group (20.00%), followed by the 140 and 280 µg/mL groups. In vivo, SI improved neurological scores from 8.3 ± 1.09 to 6.8 ± 1.68, reduced cerebral infarction volume by 18.49%, and alleviated brain edema by 10.42% (p < 0.05). SI also decreased malondialdehyde (MDA) and LDH levels by 31.15% and 39.46%, respectively, while increasing the activity of antioxidant enzymes: superoxide dismutase (SOD) by 11.70%, catalase (CAT) by 26.09%, and glutathione peroxidase (GSH-px) by 27.55% (p < 0.01). Scratch assay results showed that SI restored the impaired migratory ability of the OGD/R-treated PC12 cells, further supporting its role in cellular repair. A Western blot analysis demonstrated the upregulation of nuclear factor erythroid 2–related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NAD(P)H:quinone oxidoreductase 1 (NQO1) and the downregulation of Kelch-like, ECH-associated protein 1 (Keap1) in the cerebral ischemia–reperfusion model. Conclusions: These findings indicate that soy isoflavone confers significant neuroprotective effects against cerebral ischemia–reperfusion injury by enhancing endogenous antioxidant defense mechanisms, reducing oxidative stress, inhibiting apoptosis, and promoting cell migration. The protective effects are likely mediated through the activation of the Nrf2/Keap1 signaling pathway, supporting the therapeutic potential of SI in ischemic stroke treatment. Full article