茶多酚、维生素C对染石英尘大鼠氧化损伤的缓解作用

目的 探讨抗氧化剂茶多酚、维生素C对染尘大鼠血液中一氧化氮及抗氧化酶活性的影响。方法 Wistar大鼠随机分成对照组、石英粉尘组及预防组（茶多酚组,茶多酚＋Vit C组）。检测实验大鼠血液中NO和NOS、SOD、GSH－Px的活性。结果 与石英粉尘组比较,预防组大鼠血液中NO的含量及NOS活性下降,SOD、GSH－Px活性上升。结论 抗氧化剂茶多酚、维生素C对石英粉尘引起的氧化损伤有一定的缓解作用。     

Polyphenols and Human Health: The Role of Bioavailability

Polyphenols are a group of phytochemicals with potential health-promoting effects. They are classified as flavonoid (flavonols, flavanols, flavones, flavanones, isoflavones, and anthocyanins) and non-flavonoid molecules (phenolic acids, hydroxycinnamic acids, lignans, stilbenes, and tannins). Although an increasing number of trials have shown a correlation among polyphenol consumption and a reduction in risk factors for chronic diseases, discrepancies in explaining their positive effects have been found in terms of the bioavailability. In fact, polyphenols show a low bioavailability due to several factors: interaction with the food matrix, the metabolic processes mediated by the liver (phase I and II metabolism), intestine and microbiota. On the other hand, the biological activities of phenol compounds may be mediated by their metabolites, which are produced in vivo, and recent studies have confirmed that these molecules may have antioxidant and anti-phlogistic properties. This review discusses the studies performed in vivo, which consider the polyphenol bioavailability and their different food sources. Factors influencing the biological effects of the main classes of polyphenols are also considered.     

Berry-Derived Polyphenols in Cardiovascular Pathologies: Mechanisms of Disease and the Role of Diet and Sex

Cardiovascular disease (CVD) prevalence, pathogenesis, and manifestation is differentially influenced by biological sex. Berry polyphenols target several signaling pathways pertinent to CVD development, including inflammation, oxidative stress, and cardiac and vascular remodeling, and there are innate differences in these pathways that also vary by sex. There is limited research systematically investigating sex differences in berry polyphenol effects on these pathways, but there are fundamental findings at this time that suggest a sex-specific effect. This review will detail mechanisms within these pathological pathways, how they differ by sex, and how they may be individually targeted by berry polyphenols in a sex-specific manner. Because of the substantial polyphenolic profile of berries, berry consumption represents a promising interventional tool in the treatment and prevention of CVD in both sexes, but the mechanisms in which they function within each sex may vary.     

Aspects of antioxidant foods and supplements in health and disease

Free radicals generated as byproducts of normal metabolism can damage biologically relevant molecules. When their generation is increased, damage can also be increased, resulting in the development of many pathological conditions. Antioxidant defenses protect the body from the detrimental effects of free radicals. Dietary fruits and vegetables provide a reasonable amount of compounds that act as physiological antioxidants. Although existing knowledge does not allow a final and conclusive assessment of the relevance of antioxidants for health, it does provide the basis for its rational consideration. This paper addresses the specific aspects of antioxidant supplementation in health and disease.     

Effect of Polyphenol-Rich Foods,Juices, and Concentrates on Recovery from Exercise Induced Muscle Damage: A Systematic Review and Meta-Analysis

Objectives. To determine the effects of consuming polyphenol-rich foods, juices and concentrates on recovery from exercise-induced muscle damage (EIMD). Method. Eligibility criteria. Randomised and quasi-randomised placebo-controlled trials with a parallel or cross-over design evaluating the effects of consuming polyphenol-rich foods, juices and concentrates on recovery from EIMD in humans. Eligible studies included at least one of the primary outcome measures: maximal isometric voluntary contraction; MIVC, delayed onset muscle soreness; DOMS, or countermovement jump; CMJ. Information sources. AMED, Cochrane Central Register of Controlled Trials, International Clinical Trials Registry Platform, PUBMED, SCOPUS (Elsevier), SPORTDiscus (EBSCO), and the UK Clinical Trials Gateway were searched from inception to September 2020. Risk of bias and quality of evidence. Risk of bias was assessed using Cochrane Risk of Bias 2 tool. Quality of the evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation framework. Synthesis of results. Random effects models were used to determine the effect of polyphenol supplementation on recovery from EIMD. Data are presented as standardised mean differences (SMD) with 95% confidence intervals (CI). Results. Included studies. Twenty-five studies were included; 15 had a parallel, and 10 had a cross-over design. A total of 527 participants (male: n = 425; female: n = 102) were included in the meta-analysis. Synthesis of results. Consumption of polyphenol-rich foods, juices and concentrates accelerated recovery of MIVC immediately post-exercise (SMD = 0.23, 95% CI 0.04, 0.42; p = 0.02; low-quality evidence), 24 h (SMD = 0.39, 95% CI 0.15, 0.62; p = 0.001; low-quality evidence), 48 h (SMD = 0.48, 95% CI 0.28, 0.67; p < 0.001; moderate-quality evidence), 72 h (SMD = 0.29, 95% CI 0.11, 0.46; p = 0.001; low-quality evidence) and 96 h post-exercise (SMD = 0.50, 95% CI 0.16, 0.83; p = 0.004; very low-quality evidence). DOMS was reduced at 24 h (SMD = −0.29, 95% CI −0.47, −0.11; p = 0.002; low-quality evidence), 48 h (SMD = −0.28, 95% CI −0.46, −0.09; p = 0.003; low-quality evidence) and 72 h post-exercise (SMD = −0.46, 95% CI −0.69, −0.24; p < 0.001; very low-quality evidence). CMJ height was greater immediately post-exercise (SMD = 0.27, 95% CI 0.01, 0.53; p = 0.04; low-quality evidence), at 24 h (SMD = 0.47, 95% CI 0.11, 0.83; p = 0.01; very low-quality evidence), 48 h (SMD = 0.58, 95% CI 0.24, 0.91; p < 0.001; very low-quality evidence) and 72 h post-exercise (SMD = 0.57, 95% CI 0.03, 1.10; p = 0.04; very low-quality evidence). Polyphenol supplementation did not alter creatine kinase, c-reactive protein, and interleukin−6 at any time points. At 72 h post-exercise, protein carbonyls (SMD = −0.64, 95% CI −1.14, −0.14; p = 0.01) were reduced. Discussion. Limitations of evidence. Risk of bias was high for 10 studies and moderate for 15. Sensitivity analyses excluding the high risk of bias studies reduced the SMDs for MIVC and DOMS, and for CMJ effects at 24 and 48 h were no longer statistically significant. Interpretation. Consuming polyphenol-rich foods, juices and concentrates accelerated recovery of muscle function while reducing muscle soreness in humans. Maximal benefit occurred 48–72 h post-exercise, however, the certainty of the evidence was moderate to very low. Supplementation could be useful when there is limited time between competitive events and impaired recovery could negatively impact performance.     

A review of the mechanisms and effectiveness of dietary polyphenols in reducing oxidative stress and thrombotic risk

Dietary sources of polyphenols, which are derivatives and/or isomers of flavones, isoflavones, flavonols, catechins and phenolic acids, possess antioxidant properties and therefore might be important in preventing oxidative‐stress‐induced platelet activation and attenuating adverse haemostatic function. Free radicals, including reactive oxygen and nitrogen species, promote oxidative stress, leading to platelet hyperactivation and the risk of thrombosis. The consumption of antioxidant/polyphenol rich foods might therefore impart anti‐thrombotic and cardiovascular protective effects via their inhibition of platelet hyperactivation or aggregation. Most commonly‐used anti‐platelet drugs such as aspirin block the cyclooxygenase (COX)‐1 pathway of platelet activation, similar to the action of antioxidants with respect to neutralising hydrogen peroxide (H₂O₂), with a similar effect on thromboxane production via the COX‐1 pathway. Polyphenols also target various additional platelet activation pathways (e.g. by blocking platelet‐ADP, collagen receptors); thus alleviating fibrinogen binding to platelet surface (GPIIb‐IIIa) receptors, reducing further platelet recruitment for aggregation and inhibiting platelet degranulation. As a result of the ability of polyphenols to target additional pathways of platelet activation, they may have the potential to substitute or complement currently used anti‐platelet drugs in sedentary, obese, pre‐diabetic or diabetic populations who can be resistant or sensitive to pharmacological anti‐platelet therapy.     

Efficacy of Polyphenols in the Management of Dyslipidemia: A Focus on Clinical Studies

Polyphenols (PLPs), phytochemicals found in a wide range of plant-based foods, have gained extensive attention in view of their antioxidant, anti-inflammatory, immunomodulatory and several additional beneficial activities. The health-promoting effects noted in animal models of various non-communicable diseases explain the growing interest in these molecules. In particular, in vitro and animal studies reported an attenuation of lipid disorders in response to PLPs. However, despite promising preclinical investigations, the effectiveness of PLPs in human dyslipidemia (DLP) is less clear and necessitates revision of available literature. Therefore, the present review analyzes the role of PLPs in managing clinical DLP, notably by dissecting their potential in ameliorating lipid/lipoprotein metabolism and alleviating hyperlipidemia, both postprandially and in long-term interventions. To this end, PubMed was used for article search. The search terms included polyphenols, lipids, triglycerides, cholesterol, LDL-cholesterol and /or HDL-cholesterol. The critical examination of the trials published to date illustrates certain benefits on blood lipids along with co-morbidities in participant’s health status. However, inconsistent results document significant research gaps, potentially owing to study heterogeneity and lack of rigor in establishing PLP bioavailability during supplementation. This underlines the need for further efforts in order to elucidate and support a potential role of PLPs in fighting DLP.     

川崎病患儿血小板激活参数和凝血功能检测及意义

目的探讨血小板活化及凝血功能检测在川崎病(KD)诊疗中的意义。方法收集川崎病患儿40例于治疗前及治疗后检测平均血小板内容物浓度(MPC)、活化部分凝血活酶时间(APTT)、纤维蛋白原(FIB)、凝血酶时间(TT)、凝血酶原时间(PT);40例健康儿童为对照组。结果 KD组患儿治疗前及治疗后MPC水平显著低于正常对照组(P0.05)。KD组患儿治疗前FIB水平显著高于正常对照组(P0.05),治疗后FIB水平回复正常(P0.05)。其余结果比较,差异均无统计学意义(P0.05)。结论 FIB与活化的血小板相互作用促进了KD急性冠状动脉血栓的形成。KD治疗前MPC降低和FIB增高可作为KD早期辅助诊断的重要指标。在KD诊疗中观测MPC与FIB水平有助于临床及时了解病情,判断预后及转归。     

The Role of Macronutrients,Micronutrients and Flavonoid Polyphenols in the Prevention and Treatment of Osteoporosis

Osteoporosis is considered an age-related disorder of the skeletal system, characterized primarily by decreased bone mineral density (BMD), microstructural quality and an elevated risk of fragility fractures. This silent disease is increasingly becoming a global epidemic due to an aging population and longer life expectancy. It is known that nutrition and physical activity play an important role in skeletal health, both in achieving the highest BMD and in maintaining bone health. In this review, the role of macronutrients (proteins, lipids, carbohydrates), micronutrients (minerals—calcium, phosphorus, magnesium, as well as vitamins—D, C, K) and flavonoid polyphenols (quercetin, rutin, luteolin, kaempferol, naringin) which appear to be essential for the prevention and treatment of osteoporosis, are characterized. Moreover, the importance of various naturally available nutrients, whether in the diet or in food supplements, is emphasized. In addition to pharmacotherapy, the basis of osteoporosis prevention is a healthy diet rich mainly in fruits, vegetables, seafood and fish oil supplements, specific dairy products, containing a sufficient amount of all aforementioned nutritional substances along with regular physical activity. The effect of diet alone in this context may depend on an individual’s genotype, gene-diet interactions or the composition and function of the gut microbiota.     

The Role of Natural Antioxidants in the Prevention of Dementia—Where Do We Stand and Future Perspectives

Dementia, and especially Alzheimer’s disease (AD), puts significant burden on global healthcare expenditure through its increasing prevalence. Research has convincingly demonstrated the implication of oxidative stress in the pathogenesis of dementia as well as of the conditions which increase the risk of developing dementia. However, drugs which target single pathways have so far failed in providing significant neuroprotection. Natural antioxidants, due to their effects in multiple pathways through which oxidative stress leads to neurodegeneration and triggers neuroinflammation, could prove valuable weapons in our fight against dementia. Although efficient in vitro and in animal models of AD, natural antioxidants in human trials have many drawbacks related to the limited bioavailability, unknown optimal dose, or proper timing of the treatment. Nonetheless, trials evaluating several of these natural compounds are ongoing, as are attempts to modify these compounds to achieve improved bioavailability.     

Supplementation with Spirulina platensis Prevents Uterine Diseases Related to Muscle Reactivity and Oxidative Stress in Rats Undergoing Strength Training

Strength training increases systemic oxygen consumption, causing the excessive generation of reactive oxygen species, which in turn, provokes oxidative stress reactions and cellular processes that induce uterine contraction. The aim of this study was to evaluate the possible protective effect of Spirulina platensis (SP), an antioxidant blue algae, on the contractile and relaxation reactivity of rat uterus and the balance of oxidative stress/antioxidant defenses. Female Wistar rats were divided into sedentary (CG), trained (TG), and T + supplemented (TG50, TG100) groups. Reactivity was analyzed by AQCAD, oxidative stress was evaluated by the malondialdehyde (MDA) formation, and the antioxidant capacity was measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Strength training increased contractile reactivity and decreased the pharmaco-mechanical component of relaxing reactivity in rat uterus. In addition, training decreased oxidation inhibition in the plasma and exercise increased oxidative stress in the uterine tissue; however, supplementation with algae prevented this effect and potentiated the increase in antioxidant capacity. Therefore, this study demonstrated that food supplementation prevents changes in reactivity and oxidative stress induced by strength training in a rat uterus, showing for the first time, that the uterus is a target for this exercise modality and antioxidant supplementation with S. platensis is an alternative means of preventing uterine dysfunction.     

力竭运动致大鼠心肌损伤及S100A4蛋白表达变化

目的观察S100A4蛋白在力竭运动损伤心肌组织中的表达变化,探讨S100A4蛋白对力竭运动损伤心肌组织的作用。方法 W istar大鼠12只,随机分为对照组和力竭运动组,大鼠进行力竭训练10d后,取血及心肌组织,用光镜和电镜对心肌进行组织学观察;采用蛋白免疫印迹(western-b lot)法和免疫组织化学法检测心肌蛋白表达。结果力竭运动组大鼠心肌组织苏木精-伊红(HE)染色可见大鼠心肌和血管内皮细胞空泡变性和心肌间质水肿等;电镜可见血管内皮细胞发生典型细胞凋亡特征;W estern-b lot结果表明,对照组心肌中S100A4蛋白弱表达,而力竭运动组S100A4蛋白表达量升高;免疫组化结果显示,与对照组比较,力竭运动组心肌中S100A4蛋白表达升高1.68倍,且在心肌和血管内皮细胞中均有表达。结论力竭运动造成大鼠心肌损伤,S100A4蛋白在损伤心肌中表达升高。     

Consumption of New Zealand Blackcurrant Extract Improves Recovery from Exercise-Induced Muscle Damage in Non-Resistance Trained Men and Women: A Double-Blind Randomised Trial

Background: Blackcurrant is rich in anthocyanins that may protect against exercise-induced muscle damage (EIMD) and facilitate a faster recovery of muscle function. We examined the effects of New Zealand blackcurrant (NZBC) extract on indices of muscle damage and recovery following a bout of strenuous isokinetic resistance exercise. Methods: Using a double-blind, randomised, placebo controlled, parallel design, twenty-seven healthy participants received either a 3 g·day⁻¹ NZBC extract (n = 14) or the placebo (PLA) (n = 13) for 8 days prior to and 4 days following 60 strenuous concentric and eccentric contractions of the biceps brachii muscle on an isokinetic dynamometer. Muscle soreness (using a visual analogue scale), maximal voluntary contraction (MVC), range of motion (ROM) and blood creatine kinase (CK) were assessed before (0 h) and after (24, 48, 72 and 96 h) exercise. Results: Consumption of NZBC extract resulted in faster recovery of baseline MVC (p = 0.04), attenuated muscle soreness at 24 h (NZBC: 21 ± 10 mm vs. PLA: 40 ± 23 mm, p = 0.02) and 48 h (NZBC: 22 ± 17 vs. PLA: 44 ± 26 mm, p = 0.03) and serum CK concentration at 96 h (NZBC: 635 ± 921 UL vs. PLA: 4021 ± 4319 UL, p = 0.04) following EIMD. Conclusions: Consumption of NZBC extract prior to and following a bout of eccentric exercise attenuates muscle damage and improves functional recovery. These findings are of practical importance in recreationally active and potentially athletic populations, who may benefit from accelerated recovery following EIMD.     

The Effects of Beta-Hydroxy-Beta-Methylbutyrate Supplementation on Recovery Following Exercise-Induced Muscle Damage: A Systematic Review and Meta-Analysis

Background: Growing evidence suggests beta-hydroxy-beta-methylbutyrate's (HMB) positive effects on recovery following exercise-induced muscle damage (EIMD). However, findings vary substantially across studies.

Objective: A meta-analysis of randomized controlled trials was conducted to assess the effects of HMB supplementation on recovery following EIMD by assessing indirect markers of muscle damage, namely creatine kinase (CK) and lactate dehydrogenase (LDH) serum levels among healthy participants.

Method: A comprehensive search was performed on electronic databases (Medline, Scopus, Cochrane Library, and Google Scholar) up to October 2017 for trials evaluating the effects of HMB on recovery following EIMD. Mean ± standard deviation of follow-up CK and LDH concentrations were extracted to calculate the effect size for meta-analysis.

Results: A total of 324 participants for CK and 229 participants for LDH were found from the 10 and 8 studies, respectively. The results revealed a significant effect of HMB supplementation on CK (weighted mean difference [WMD] = ?60.71 UL^?1; 95% confidence interval [CI], ?78.12 to ?43.29; I² = 4.1%; p_{heterogeneity} = 0.40) and LDH reduction (WMD = ?15.42 UL^?1; 95% CI, ?22.2 to ?8.6; I² = 0.0%; p_{heterogeneity} = 0.53). In addition, a subgroup analysis based on study duration (< 6 weeks vs. ≥ 6 weeks) suggested that HMB effectiveness on EIMD was statistically significant in studies over 6 weeks (p < 0.001).

Conclusions: The current evidence revealed a time-dependent effect of HMB in reducing LDH and CK serum levels among adults. HMB, therefore, may be seen as a priority muscle damage recovery agent in interventions.     

The Effects of Fruit-Derived Polyphenols on Cognition and Lung Function in Healthy Adults: A Systematic Review and Meta-Analysis

Polyphenols are plant derived nutrients that influence oxidative stress and inflammation and therefore may have positive benefits on cognition and lung function. This systematic review and meta-analysis aimed to evaluate the effects of fruit derived polyphenol intakes on cognition and lung capacity in healthy adults. In August 2020 and October 2021, Medline and Google Scholar were used to search for relevant studies examining the effects of fruit derived polyphenol intakes on cognition and/or lung function in healthy adults (<70 years old). Fourteen studies related to cognition (409 healthy subjects) and seven lung/respiratory studies (20,788 subjects) were used for the systematic review using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. The meta-analysis (using six cognition and three lung function studies) indicated a protective effect on lung function from dietary intakes of fruit-derived polyphenols. Neither a benefit nor decrement from fruit-derived polyphenol intakes were detected for cognition. Human intervention trials examining the effects of polyphenol supplementation on lung function in healthy adults are scarce and intervention studies are warranted. More conclusive results are needed to provide recommendations for polyphenol supplementation to support aspects of cognition.     

葡萄籽原花青素对过氧化氢致大鼠海马神经元损伤的保护作用

[目的]观察葡萄籽原花青素（grape seed proanthocyanidin,GSP）对过氧化氢（H2O2）致大鼠海马神经元损伤的保护作用。[方法]实验分为5组：阴性对照组（A组）、H2O2模型组（B组）、GSP低剂量组（C组,1.25mg／L）、GSP中剂量组（D组,2.50mg／L）和GSP高剂量组（E组,5.00mg／L）。采用原代细胞培养的方法,建立H2O2致海马细胞氧化损伤模型。观察各组细胞形态和超微结构;采用四甲基偶氮唑盐（MTT）比色法检测细胞存活率;化学比色法检测细胞内超氧化物歧化酶（SOD）活性、活性氧（ROS）和丙二醛（MDA）冶量;TdT介导的dUTP缺口末端标记法（TUNEL法）检测细胞凋亡率。[结果]形态学观察C、D、E组均可减轻H2O2诱导的海马细胞氧化损伤。与B组相比,C、D、E组细胞存活率由31.97％分别上升到61.42％、68.47％和80.04％（P〈0.01）;细胞凋亡率由8.83％分别降低到3.50％、2.83％和2.00％（P〈0.01）;D、E组细胞内SOD含量明显增加（P〈0.05或P〈0.01）,C、D、E组抑制ROS能力和减少MDA含量明显增加（P〈0.01）。[结论]GSP对H2O2诱导的海马细胞氧化损伤有明显的保护作用,其作用机制可能与提高海马细胞的抗氧化能力以及减少凋亡率有关。     

A Review of Rehabilitation Benefits of Exercise Training Combined with Nutrition Supplement for Improving Protein Synthesis and Skeletal Muscle Strength in Patients with Cerebral Stroke

Cerebral vascular accident (CVA) is one of the main causes of chronic disability, and it affects the function of daily life, so it is increasingly important to actively rehabilitate patients’ physical functions. The research confirmed that the nutrition supplement strategy is helpful to improve the effect of sports rehabilitation adaptation and sports performance. The patients with chronic strokes (whose strokes occur for more than 6 months) have special nutritional needs while actively carrying out rehabilitation exercises, but there are still few studies to discuss at present. Therefore, this paper will take exercise rehabilitation to promote muscle strength and improve muscle protein synthesis as the main axis and, through integrating existing scientific evidence, discuss the special needs of chronic stroke patients in rehabilitation exercise intervention and nutrition supplement one by one. At the same time, we further evaluated the physiological mechanism of nutrition intervention to promote training adaptation and compared the effects of various nutrition supplement strategies on stroke rehabilitation. Literature review pointed out that immediately supplementing protein nutrition (such as whey protein or soybean protein) after resistance exercise or endurance exercise can promote the efficiency of muscle protein synthesis and produce additive benefits, thereby improving the quality of muscle tissue. Recent animal research results show that probiotics can prevent the risk factors of neural function degradation and promote the benefits of sports rehabilitation. At the same time, natural polyphenols (such as catechin or resveratrol) or vitamins can also reduce the oxidative stress injury caused by animal stroke and promote the proliferation of neural tissue. In view of the fact that animal research results still make up the majority of issues related to the role of nutrition supplements in promoting nerve repair and protection, and the true benefits still need to be confirmed by subsequent human studies. This paper suggests that the future research direction should be the supplement of natural antioxidants, probiotics, compound nutritional supplements, and integrated human clinical research.     

茶多酚抑制促癌物TPA促癌作用抗氧化机制研究

用促癌物ＴＰＡ涂抹小鼠皮肤，并涂抹绿茶多酚（ＧＴＰ）。结果表明：ＧＴＰ可明显抑制涂抹ＴＰＡ诱导的鸟氨酸脱羧酶（ＯＤＣ）活性增高及某些抗氧化酶（ＣＡＴ、ＧＲ、ＧＳＴ）活性降低。另外，在体外试验中加入０．２、０．４、０．８ｍｇ／ＬＧＴＰ可明显抑制ＴＰＡ诱发大鼠多型核白细胞（ＰＭＮｓ）生成的过氧化氢，并有一定的剂量—反应趋势。上述结果表明ＧＴＰ抑制ＴＰＡ促癌作用的机制可能与其抗氧化作用有关。     

Quercetin Alleviates Oxidative Damage by Activating Nuclear Factor Erythroid 2-Related Factor 2 Signaling in Porcine Enterocytes

Oxidative stress has been implicated in the etiology of multiple gastrointestinal disorders, such as irritable bowel syndrome and inflammatory bowel disease. This study was conducted to evaluate effects of natural product quercetin on diquat-induced oxidative stress in porcine enterocytes and underlying mechanisms. Intestinal porcine epithelial cell line 1 (IPEC-1) cells pretreated with or without quercetin (5 μM, 24 h) were incubated with vehicle or diquat (100 μM) for 6 h. The results showed that diquat treatment induced apoptosis in a caspase-3-dependent manner, as accompanied by elevated reactive oxygen species (ROS) production, increased mitochondrial depolarization, and reduced the abundance of tight junction proteins. These adverse effects of diquat were remarkably abrogated by quercetin administration. Further study indicated that the protective effect of quercetin was associated with elevated protein abundance of nuclear factor erythroid 2-related factor 2 (Nrf2) and increased intracellular glutathione (GSH) content. Interestingly, the beneficial effects of quercetin on diquat-induced oxidative damage were abolished by all-trans-retinoic acid (Atra), a specific inhibitor of Nrf2, indicating a Nrf2-dependent regulation manner. The results show that quercetin attenuates diquat-induced cell injury by promoting protein abundance of Nrf2 and regulating GSH-related redox homeostasis in enterocytes. These findings provide new insights into a function role of quercetin in maintaining intestinal homeostasis.