Blackberry extract attenuates oxidative stress through up-regulation of Nrf2-dependent antioxidant enzymes in carbon tetrachloride-treated rats

Sulforaphane prevents diabetes-induced hepatic ferroptosis by activating Nrf2 signaling axis

Recently, we characterized the ferroptotic phenotype in the liver of diabetic mice and revealed nuclear factor (erythroid-derived-2)-related factor 2 (Nrf2) inactivation as an integral part of hepatic injury. Here, we aim to investigate whether sulforaphane, an Nrf2 activator and antioxidant, prevents diabetes-induced hepatic ferroptosis and the mechanisms involved. Male C57BL/6 mice were divided into four groups: control (vehicle-treated), diabetic (streptozotocin-induced; 40 mg/kg, from Days 1 to 5), diabetic sulforaphane-treated (2.5 mg/kg from Days 1 to 42) and non-diabetic sulforaphane-treated group (2.5 mg/kg from Days 1 to 42). Results showed that diabetes-induced inactivation of Nrf2 and decreased expression of its downstream antiferroptotic molecules critical for antioxidative defense (catalase, superoxide dismutases, thioredoxin reductase), iron metabolism (ferritin heavy chain (FTH1), ferroportin 1), glutathione (GSH) synthesis (cystine-glutamate antiporter system, cystathionase, glutamate-cysteine ligase catalitic subunit, glutamate-cysteine ligase modifier subunit, glutathione synthetase), and GSH recycling - glutathione reductase (GR) were reversed/increased by sulforaphane treatment. In addition, we found that the ferroptotic phenotype in diabetic liver is associated with increased ferritinophagy and decreased FTH1 immunopositivity. The antiferroptotic effect of sulforaphane was further evidenced through the increased level of GSH, decreased accumulation of labile iron and lipid peroxides (4-hydroxy-2-nonenal, lipofuscin), decreased ferritinophagy and liver damage (decreased fibrosis, alanine aminotransferase, and aspartate aminotransferase). Finally, diabetes-induced increase in serum glucose and triglyceride level was significantly reduced by sulforaphane. Regardless of the fact that this study is limited by the use of one model of experimentally induced diabetes, the results obtained demonstrate for the first time that sulforaphane prevents diabetes-induced hepatic ferroptosis in vivo through the activation of Nrf2 signaling pathways. This nominates sulforaphane as a promising phytopharmaceutical for the prevention/alleviation of ferroptosis in diabetes-related pathologies.

Blueberry and Blackberry Anthocyanins Ameliorate Metabolic Syndrome by Modulating Gut Microbiota and Short-Chain Fatty Acids Metabolism in High-Fat Diet-Fed C57BL/6J Mice

In this study, blueberry (Vaccinium ssp.) anthocyanins (VA) and blackberry (Rubus L.) anthocyanins (RA) were used to investigate the effects on metabolic syndrome (MetS) and the potential mechanisms. Importantly, all of the data presented in this study were obtained from experiments conducted on mice. As a result, VA and RA reduced body weight gain and fat accumulation while improving liver damage, inflammation, glucose, and lipid metabolism induced by a high-fat diet. Moreover, VA and RA regulated the gut microbiota composition, decreasing the pro-obesity and proinflammation bacteria taxa, such as the phylum Actinobacterium and the genera Allobaculum and Bifidobacterium, and increasing those negatively associated with obesity and inflammation, such as the phylum Bacteroidetes and the genera Prevotella and Oscillospira. Additionally, the supplementation with VA and RA reversed the elevated levels of valeric, caproic, and isovaleric acids observed in the high-fat diet (HFD) group, bringing them closer to the levels observed in the Chow group. This reversal indicated that alterations in the composition and abundance of gut microbiota may contribute to the restoration of short-chain fatty acids (SCFAs) levels. Additionally, PICRUSt2 exhibited that cyanamino acid metabolism and betalain biosynthesis might be the major metabolic pathways in the HVA group compared with the HFD group, while in the HRA group, it was the phosphotransferase system. These findings suggest that VA and RA can ameliorate MetS by modulating the gut microbiota and production of SCFAs.

Phytochemicals Determination, and Antioxidant, Antimicrobial, Anti-Inflammatory and Anticancer Activities of Blackberry Fruits

A comprehensive characterization of the phytochemicals present in a blackberry fruit extract by HPLC-TOF-MS has been carried out. The main compounds in the extract were ursane-type terpenoids which, along with phenolic compounds, may be responsible for the bioactivity of the extract. In vitro antioxidant capacity was assessed through Folin–Ciocalteu (31.05 ± 4.9 mg GAE/g d.w.), FRAP (637.8 ± 3.2 μmol Fe2+/g d.w.), DPPH (IC50 97.1 ± 2.4 μg d.w./mL) and TEAC (576.6 ± 8.3 μmol TE/g d.w.) assays. Furthermore, the extract exerted remarkable effects on in vitro cellular antioxidant activity in HUVEC cells at a concentration of 5 mg/mL. Antimicrobial activity of the extract was also tested. Most sensible microorganisms were Gram-positive bacteria, such as E. faecalis, B. cereus and Gram-negative E. coli (MBC of 12.5 mg/mL). IC50 values against colon tumoral cells HT-29 (4.9 ± 0.2 mg/mL), T-84 (5.9 ± 0.3 mg/mL) and SW-837 (5.9 ± 0.2 mg/mL) were also obtained. Furthermore, blackberry extract demonstrated anti-inflammatory activity inhibiting the secretion of pro-inflammatory IL-8 cytokines in two cellular models (HT-29 and T-84) in a concentration-dependent manner. These results support that blackberry fruits are an interesting source of bioactive compounds that may be useful in the prevention and treatment of different diseases, mainly related to oxidative stress.

Blackberry-Loaded AgNPs Attenuate Hepatic Ischemia/Reperfusion Injury via PI3K/Akt/mTOR Pathway

Liver ischemia-reperfusion injury (IRI) is a pathophysiological insult that often occurs during liver surgery. Blackberry leaves are known for their anti-inflammatory and antioxidant activities. Aims: To achieve site-specific delivery of blackberry leaves extract (BBE) loaded AgNPs to the hepatocyte in IRI and to verify possible molecular mechanisms. Methods: IRI was induced in male Wister rats. Liver injury, hepatic histology, oxidative stress markers, hepatic expression of apoptosis-related proteins were evaluated. Non-targeted metabolomics for chemical characterization of blackberry leaves extract was performed. Key findings: Pre-treatment with BBE protected against the deterioration caused by I/R, depicted by a significant improvement of liver functions and structure, as well as reduction of oxidative stress with a concomitant increase in antioxidants. Additionally, BBE promoted phosphorylation of antiapoptotic proteins; PI3K, Akt and mTOR, while apoptotic proteins; Bax, Casp-9 and cleaved Casp-3 expressions were decreased. LC-HRMS-based metabolomics identified a range of metabolites, mainly flavonoids and anthocyanins. Upon comprehensive virtual screening and molecular dynamics simulation, the major annotated anthocyanins, cyanidin and pelargonidin glucosides, were suggested to act as PLA2 inhibitors. Significance: BBE can ameliorate hepatic IRI augmented by BBE-AgNPs nano-formulation via suppressing, oxidative stress and apoptosis as well as stimulation of PI3K/Akt/mTOR signaling pathway.

The effect of anthocyanins supplementation on liver enzymes: A systematic review and meta-analysis of randomized clinical trials

This systematic review and meta-analysis aimed to assess effect of consuming anthocyanins (ACNs; pure ACNs or products containing ACNs) on liver enzymes levels including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT). Although no significant impact was detected on the liver enzymes, a significant reduction was observed on ALT (WMD = -4.932 U/L, 95% CI = -9.848 to -0.015, p = .049) and AST (WMD = -3.464 U/L, 95% CI = -6.034 to -0.894, p = .008) in the studies that examined them as primary outcomes. A significant decrease was found on AST among the healthy subjects (WMD = -4.325 U/L, 95% CI = -8.516 to -0.134, p = .043) and in the studies that used products containing ACNs as intervention (WMD = -2.201 U/L, 95% CI = -4.275 to -0.127, p = .037). Although no significant relation was detected between ACNs dosage and the liver enzymes, significant associations were found between the duration of trial with ALT (ALT: slope: 0.09, 95% CI = 0.040 to 0.139, p = .0003) and AST (slope: 0.076, 95% CI = 0.037 to 0.115, p = .0001). In conclusion, although ACNs had no significant effect on the liver enzymes, a significant decrease was discovered on ALT and AST in the studies that evaluated them as primary outcomes. A significant reduction was observed in AST in the healthy individuals and in the studies used products containing ACNs as intervention. Significant relations were also found between the duration of trial with ALT and AST. Further studies are required to confirm these results.

Pterocarpus santalinus L. extract mitigates gamma radiation-inflicted derangements in BALB/c mice by Nrf2 upregulation

Plant-based natural extracts contain several nutrients and bioactive compounds, such as phenolics and flavonoids, that possess various health-promoting activities. This study investigated the effects of polyphenols from Pterocarpus santalinus hydroalcoholic extract (PSHE) against gamma radiation-induced derangements via the upregulation of Nrf2. Ultra High Performance Liquid Chromatography Coupled to High Resolution Mass Spectrometry (UHPLC-HRMS/MS) analysis was performed to identify the possible radioprotectors. In vivo and in vitro studies, namely Real-Time-PCR (RT-PCR) analysis, Reactive Oxygen Species (ROS) scavenging activity, lipid peroxidation and GSH levels, DNA damage and cell death studies, anti-inflammatory (Sandwich ELISA), immunomodulatory studies (antibody staining), and model free radical scavenging assays, were performed. Vanillic acid, protocatechuic acid, para-hydroxybenzoic acid, chlorogenic acid, TNF-α inhibitor (Eudesmin), isoflavone (Daidzein 7-o-glucoside), astragalin (Kaempferol 3-o-glycoside), and other polyphenols were identified in PSHE using UHPLC-HRMS/MS analysis. Prophylactic administration of PSHE (-1 h) rendered more than 33% survival in mice exposed to 8 Gy whole-body-irradiation with increased mice survival and recovery of bone marrow and spleen cellularity. Real-time RT-PCR analysis showed that PSHE treatment (50 µg/mL) upregulated Nrf2, HO-1, and GPX-1 in mice splenocytes. At 50 µg/mL, PSHE reduced ROSscavenging activity, mitochondrial and spleen membrane lipid peroxidation levels, DNA damage, and cell death, and increased GSH levels. At 10 µg/mL, PSHE treatment diminished the content of IL-6 and TNF-α. At 50 µg/mL, PSHE suppressed lymphocyte proliferation. These findings indicate that polyphenols of PSHE possess marked antioxidant, anti-inflammatory, and immunomodulatory capacities, which play important roles in the prevention of radiation damage.

Dehydroepiandrosterone attenuates LPS-induced inflammatory responses via activation of Nrf2 in RAW264.7 macrophages

Dehydroepiandrosterone (DHEA) is the major steroid hormone in humans and animals, which can regulate the body's inflammatory responses. However, the detail mechanism of this beneficial function is still poorly understood. The present study aimed to explore the anti-inflammation effect of DHEA and its underlying molecular mechanism in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. The findings showed that DHEA significantly inhibited the inflammation-related mediators production and pro-inflammatory cytokines expression level. Further research found that DHEA obviously blocked the LPS-stimulated PI3K/AKT, MAPK and NF-κB activation in RAW 264.7 cells. Meanwhile, DHEA enhanced the autophagy-dependent Keap1 protein degradation, subsequently activated the Nrf2 pathway to alleviate the redox imbalance and inflammatory responses. In conclusion, our data demonstrated that DHEA suppresses inflammatory responses through the activation of Nrf2 and inhibition of NF-κB in LPS-stimulated macrophages.

Anthocyanins: From the Field to the Antioxidants in the Body

Anthocyanins are biologically active water-soluble plant pigments that are responsible for blue, purple, and red colors in various plant parts-especially in fruits and blooms. Anthocyanins have attracted attention as natural food colorants to be used in yogurts, juices, marmalades, and bakery products. Numerous studies have also indicated the beneficial health effects of anthocyanins and their metabolites on human or animal organisms, including free-radical scavenging and antioxidant activity. Thus, our aim was to review the current knowledge about anthocyanin occurrence in plants, their stability during processing, and also the bioavailability and protective effects related to the antioxidant activity of anthocyanins in human and animal brains, hearts, livers, and kidneys.

Using an UPLC/MS-based untargeted metabolomics approach for assessing the antioxidant capacity and anti-aging potential of selected herbs

Aging is an unavoidable fate that afflicts all life, during this process in mammals reactive oxygen species (ROS) are generated which stimulate tyrosinase, elastase and collagenase activities that actively participate in skin aging. Therefore, the maintenance of antioxidant homeostasis is an important anti-aging strategy for skin. Nature has excellent anti-aging remedies that act externally as well as internally to delay the visual signs of aging. In view of this fact, the present study investigates the in vitro anti-aging activity of five medicinal plants belonging to phenolic rich families namely Rosmarinus officinalis, Lavandula officinalis, Matricaria chamomilla, Camellia sinensis and Pelargonium graveolens. The selected plants are those most frequently used in the preparation of ethnomedicinal recipes for the prevention or treatment of aging. The inhibitory effects of the ethanolic and aqueous extracts of the five selected plants on the activity of tyrosinase, elastase, and collagenase enzymes were investigated. Furthermore, the chemical composition of the plants and the antioxidant capacity of their extracts were assessed. The results showed that R. officinalis had the highest total phenolics content which was correlated with its potent antioxidant and anti-aging activities. To pinpoint the active metabolites in the tested extracts, we evaluated the metabolite variations using ultra-performance liquid chromatography coupled with high resolution electrospray ionization-tandem mass spectrometry (UPLC-HR-ESI-MS/MS). Multivariate data analysis (MVDA) revealed that R. officinalis significantly accumulated metabolites from the aromatic diterpenoid, flavonoid and phenolic acid classes. These results indicate that rosemary can be used for further development of topical preparations with anti-aging properties.

Aging is an unavoidable fate that afflicts all life, during this process in mammals, reactive oxygen species (ROS) are generated which stimulate tyrosinase, elastase and collagenase activities that actively participate in skin aging.

Effects of Prunus cerasus L. Seeds and Juice on Liver Steatosis in an Animal Model of Diet-Induced Obesity

The accumulation of adipose tissue increases the risk of several diseases. The fruits-intake, containing phytochemicals, is inversely correlated with their development. This study evaluated the effects of anthocyanin-rich tart cherries in diet-induced obese (DIO) rats. DIO rats were exposed to a high-fat diet with the supplementation of tart cherry seeds powder (DS) and seed powder plus juice (DJS). After 17 weeks, the DIO rats showed an increase of body weight, glycaemia, insulin, and systolic blood pressure. In the DS and DJS groups, there was a decrease of systolic blood pressure, glycaemia, triglycerides, and thiobarbituric reactive substances in the serum. In the DJS rats, computed tomography revealed a decrease in the spleen-to-liver attenuation ratio. Indeed, sections of the DIO rats presented hepatic injury characterized by steatosis, which was lower in the supplemented groups. In the liver of the DIO compared with rats fed with a standard diet (CHOW), a down-regulation of the GRP94 protein expression and a reduction of LC3- II/LC3-I ratio were found, indicating endoplasmic reticulum stress and impaired autophagy flux. Interestingly, tart cherry supplementation enhanced both unfolded protein response (UPR) and autophagy. This study suggests that tart cherry supplementation, although it did not reduce body weight in the DIO rats, prevented its related risk factors and liver steatosis.

Daily Consumption of an Anthocyanin-Rich Extract Made From New Zealand Blackcurrants for 5 Weeks Supports Exercise Recovery Through the Management of Oxidative Stress and Inflammation: A Randomized Placebo Controlled Pilot Study

Background: Regular exercise is essential to a healthy lifestyle but evokes an oxidative and inflammatory stress. Depending upon its intensity and duration this can result in either beneficial adaptive changes or underlying tissue damage that impacts upon long-term health and individual sporting training schedules. Functional foods containing plant bioactives have potential to support exercise through management of the detrimental aspects of exercise and complement ergonomic adaptive benefits. Aim: Previously we reported that a single consumption of a 3.2 mg/kg New Zealand blackcurrant anthocyanin-rich extract (BAE) 1 h before a 30 min rowing exercise attenuated moderate exercise-mediated oxidative stress and supported innate immunity. Here we evaluate whether the efficacy of a single consumption of BAE 1 h prior to exercise is changed after extended daily BAE consumption for 5 weeks. Results: On week 1, a single consumption of BAE 1 h before a 30 min row mediated a significant (p < 0.05) 46% reduction in post-exercise-induced malondialdehyde (MDA) by 2 h compared to a 30% reduction in the placebo group. Similar efficacy was observed 5 weeks later after daily consumption of BAE. In addition, daily BAE consumption for 5 weeks improved the efficacy to (a) resolve acute inflammation, and (b) increased plasma IL-10, salivary beta-defensin 2 (BD2) and secretory IgA. Although no change in plasma antioxidant capacity was detected, a significant (p < 0.009) positive correlation between plasma IL-10 and plasma antioxidant capacity (R 2 = 0.35) was observed on week 6 after 5 week BAE consumption suggesting IL-10 influences antioxidant properties. Using a differentiated myotubule cell-line revealed that whilst IL-10 had no direct antioxidant neutralizing action, longer-term exposure (24 h) attenuated 2,2'-Azobis(2-amidinopropane) dihydrochloride (AAPH)-induced myotubule oxidative stress, supporting a putative role for IL-10 in the modulation of cellular antioxidant systems. Conclusions: Daily consumption of BAE for 5 weeks serves to enhance the exercise recovery effectiveness of a single consumption of BAE and promotes beneficial/protective antioxidant/anti-inflammatory cellular events that facilitate exercise recovery.

Nrf2 in liver toxicology

Liver plays essential roles in the metabolism of many endogenous chemicals and exogenous toxicants. Mechanistic studies in liver have been at the forefront of efforts to probe the roles of bioactivation and detoxication of environmental toxins and toxicants in hepatotoxicity. Moreover, idiosyncratic hepatoxicity remains a key barrier in the clinical development of drugs. The now vast Nrf2 field emerged in part from biochemical and molecular studies on chemical inducers of hepatic detoxication enzymes and subsequent characterization of the modulation of drug/toxicant induced hepatotoxicities in mice through disruption of either Nrf2 or Keap1 genes. In general, loss of Nrf2 increases the sensitivity to such toxic chemicals, highlighting a central role of this transcription factor and its downstream target genes as a modifier to chemical stress. In this review, we summarize the impact of Nrf2 on the toxicology of multiple hepatotoxicants, and discuss efforts to utilize the Nrf2 response in predictive toxicology.

The effect of total anthocyanin-base standardized (Cornus mas L.) fruit extract on liver function, tumor necrosis factor α, malondealdehyde, and adiponectin in patients with non-alcoholic fatty liver: a study protocol for a double-blind randomized clinical trial

Background

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide. Evidence showed that anthocyanins might have effects on NAFLD. Protective effects of Cornelian cherry (Cornus mas L.) extract, as an anthocyanins-rich source, on liver were reported in animal studies. However, very few clinical trials were conducted in this regard. Thus, the aim of this research will be to evaluate the effect of supplementation with total anthocyanin-base standardized cornelian cherry fruit extract on liver function (Serum levels of Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), cytokeratin-18 fragment M30 (CK-18 M30), as well as steatosis and fibrosis of liver), tumor necrosis factor α (TNF-α), malondealdehyde (MDA), and adiponectin in patients with NAFLD.

Methods

In a double-blind randomized clinical trial, 80 NAFLD patients will be studied. The patients will be randomly assigned into two groups. The intervention group will receive the cornelian cherry extract, containing 320 mg.d^− 1 anthocyanins, per day for 12 weeks. The control group will also take the placebo daily for 12 weeks. Liver function (Serum levels of AST, ALT and CK-18 M30; steatosis and fibrosis of liver), serum levels of TNF-α, MDA, and adiponectin will be measured at the baseline and the end of trial for both groups and their results will be compared.

Discussion

Considering evidences about the useful impacts of anthocyanins on NAFLD, the effects of supplementation with cornelian cherry extract will be investigated on the important variables related to NAFLD.

Trial registration

Iranian Registry of Clinical Trials (IRCT20180419039359N1).

Rubus idaeus L. (red raspberry) blocks UVB-induced MMP production and promotes type I procollagen synthesis via inhibition of MAPK/AP-1, NF-κβ and stimulation of TGF-β/Smad, Nrf2 in normal human dermal fibroblasts

Chronic exposure to ultraviolet (UV) radiation causes photo-oxidation, which in turn results in the upregulation of matrix metalloproteinases (MMPs) and loss of collagen. Rubus idaeus L. (RI), also called red raspberry, is an important cash crop that contains abundant antioxidant compounds. Sanguiin H-6 and lambertianin C are the major ingredients presented in the extracts. Here, we studied the protective effect of RI on UVB-induced photoaging in normal human dermal fibroblasts (NHDFs). We found that RI notably reduced UVB-induced MMPs secretion and pro-inflammatory mediators production, and significantly suppressed UVB-induced activation of mitogen-activated protein kinase (MAPK), nuclear factor-κβ, as well as activator protein 1. Additionally, treatment of NHDFs with the ERK inhibitor (PD98059) and JNK inhibitor (SP600125) resulted in the reduction of UVB-induced MMP-1 and IL-6 expressions, which demonstrated that the inhibition of MMP-1 and IL-6 by RI is associated with the MAPK pathway. Furthermore, we also found that RI accelerated procollagen type I synthesis by activating the transforming growth factor-β/Smad pathway and enhanced the expression of cytoprotective antioxidants such as heme oxygenase-1 and NHD(P)H quinone oxidoreductase 1 by promoting nuclear factor E2-related factor 2 nuclear transfer. Overall, these findings demonstrated that RI was potentially effective in preventing UVB induced skin photoaging.

Anthocyanin Contents Enhancement with Gamma Irradiated Mutagenesis in Blackberry (Rubus fructicosus)

Effects of radiation processing on the endogenous phytochemical production in blackberry ( Rubus fructicosus L.) were investigated through a metabolites analysis, using high-performance liquid chromatography with a diode array detector and a triple quadrupole mass spectrometer (HPLC-DAD-ESI-MS/MS). Four mutant cultivar lines (B, C, D, and E) were developed through the treatment of various doses of gamma irradiation (80, 60, 40, and 20 Gy) on the control blackberry cultivar (V3). These mutant cultivar lines were selected according to their different morphological variations in leaf shape and branch color. In the present study, we performed quantitative analyses of the four standard compounds in blackberry mutant cultivars: cyanidin-3- O-glucoside, cyanidin-3- O-xyloside, cyanidin-3- O-malonylglucoside, and cyanidin-3- O-dioxalylglucoside. The HPLC fingerprints displayed different profiles for six blackberry cultivar lines, demonstrating that the accumulation of total anthocyanins was affected by the gamma irradiation. The contents of cyanidin-3- O-glucoside and cyanidin-3- O-xyloside were high in the gamma-irradiated mutant cultivars of blackberries, compared to those of the control cultivar (V3) and the cross breeding cultivar ( R. fructicosus × R. parvifolius; CB). Cyanidin-3- O-malonylglucoside and cyanidin-3- O-dioxalylglucoside were also analyzed for their quantification in six cultivar lines, as metabolites contributing to the discrimination of six cultivar lines. Among gamma irradiated mutant blackberry cultivars, the highest dose level of gamma irradiation (80 Gy) resulted in the highest cyanidin-3- O-glucoside content enhancement. Therefore, these results can be useful to determine the optimized gamma irradiated value at which anthocyanins reaches an abundant level in Rubus species.

Vitamin C protects piglet liver against zearalenone-induced oxidative stress by modulating expression of nuclear receptors PXR and CAR and their target genes

Zearalenone (ZEN), a common mycotoxin found in human food and animal feed, is effectively detoxified by vitamin C by modulation of the nuclear receptor signaling pathway.

Endogenous n-3 Fatty Acids Alleviate Carbon-Tetrachloride-Induced Acute Liver Injury in Fat-1 Transgenic Mice

n-3 polyunsaturated fatty acids (PUFAs) are beneficial for numerous models of liver diseases. The probable protective effects of n-3 PUFA against carbon-tetrachloride- (CCl₄-) induced acute liver injury were evaluated in a fat-1 transgenic mouse that synthesizes endogenous n-3 from n-6 PUFA. Fat-1 mice and their WT littermates were fed a modified AIN93 diet containing 10% corn oil and were injected intraperitoneally with a single dose of CCl₄ or vehicle. CCl₄ challenge caused severe liver injury in WT mice, as indicated by serum parameters and histopathological changes, which were remarkably ameliorated in fat-1 mice. Endogenous n-3 PUFA decreased the elevation of oxidative stress induced by CCl₄ challenge, which might be attributed to the activation of Nrf2/keap1 pathway. Additionally, endogenous n-3 PUFA reduces hepatocyte apoptosis via suppressing MAPK pathway. These findings indicate that n-3 PUFA has potent protective effects against acute liver injury induced by CCl₄ in mice, suggesting that n-3 PUFA can be used for the prevention and treatment of liver injury.

Effect of chronic consumption of blackberry extract on high-fat induced obesity in rats and its correlation with metabolic and brain outcomes

Flavonoids have been presented as potential protectors against metabolic and cognitive dysfunction. However, mechanisms underlying these 'claims' have not been sufficiently explored. To analyse the effect of long-term supplementation with blackberry extract (BE) in the context of a high-fat or a standard diet, Wistar rats were divided into 4 groups (n = 6) fed with a standard or a high-fat diet, with or without BE supplementation at 25 mg per kg body weight per day. A high-fat diet significantly impaired glucose tolerance and increased body weight, caloric ingestion, very-low-density lipoprotein, triglycerides and cholesterol. Furthermore, it was observed that a high-fat diet increased dopamine content in the prefrontal cortex and decreased brain derived neurotrophic factor (BDNF) levels both in the prefrontal cortex and in plasma. BE supplementation only affected some of these aspects. BE slightly improved glucose metabolism and significantly decreased levels of lactate, independent of diet. BE decreased levels of BDNF and also interacted with the dopaminergic system, increasing dopamine turnover in the striatum, and reverting dopamine content induced by a high-fat diet in the prefrontal cortex. This study shows that, despite some particular benefits of anthocyanin supplementation, some long-term effects may not be desirable and further studies are needed to optimize ingestion conditions.

Nrf2/antioxidant defense pathway is involved in the neuroprotective effects of Sirt1 against focal cerebral ischemia in rats after hyperbaric oxygen preconditioning

Sirtuin 1 (Sirt1) is a class III histone deacetylase involved in neuroprotection induced by hyperbaric oxygen preconditioning (HBO-PC) in animal models of ischemia. However, the underlying mechanisms remain to be illustrated. In the present study, rats exposed to middle cerebral artery occlusion (MCAO) were used to establish an ischemic stroke model. The infarct volume ratio, neurobehavioral score, and expressions of Sirt1, nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), and superoxide dismutase 1 (SOD1) were evaluated at 7 days after reperfusion, and the level of malondialdehyde (MDA) was used to assess oxidative stress. HBO-PC increased the expression of Sirt1 and reduced infarct volume ratio and neurobehavioral deficit in MCAO rats. Meanwhile, HBO-PC also increased expression of Nrf2, HO-1, and SOD1 and decreased MDA content. Furthermore, either Sirt1 or Nrf2 knockdown by short interfering RNA (siRNA) inhibited the expression of Nrf2, HO-1, and SOD1 and eliminated the neuroprotective effects of HBO-PC. Taken together, the results suggest that the Nrf2/antioxidant defense pathway is involved in the long lasting neuroprotective effects of Sirt1 induced by HBO-PC against transient focal cerebral ischemia.

Tucum-Do-Cerrado (Bactris setosa Mart.) Consumption Modulates Iron Homeostasis and Prevents Iron-Induced Oxidative Stress in the Rat Liver

This study investigated the effect of tucum-do-cerrado consumption in the oxidative status of iron-supplemented rats. Four groups of rats were treated: Control (AIN-93G), Tuc (AIN-93G added of tucum-do-cerrado), Fe (AIN-93G iron-enriched), or TucFe (AIN-93G with tucum-do-cerrado and iron-enriched) diet, for 30 days. Iron-enriched diet increased serum, liver, spleen, and intestine iron levels; transferrin saturation; liver lipid oxidation; mRNA levels of hepatic Hamp and Bmp6, and Nrf2 in the intestine. Tucum-do-cerrado consumption reduced spleen lipid and protein oxidation; mRNA levels of hepatic Hamp and Ftl, and increased serum antioxidant capacity and hepatic mRNA levels of Bmp6, Hmox1, Nqo1, and Nrf2. TucFe diet consumption abrogated the liver Hamp iron-induced up-regulation, prevented intestinal iron accumulation; hepatic lipid peroxidation; splenic protein damage, and the increase of catalase, glutathione reductase, and glutathione peroxidase activity in some tissues. These results suggest that tucum-do-cerrado protects tissues against oxidative damage, by reducing iron availability in liver and consequently inhibiting liver Hamp expression.

Cell Systems to Investigate the Impact of Polyphenols on Cardiovascular Health

Polyphenols are a diverse group of micronutrients from plant origin that may serve as antioxidants and that contribute to human health in general. More specifically, many research groups have investigated their protective effect against cardiovascular diseases in several animal studies and human trials. Yet, because of the excessive processing of the polyphenol structure by human cells and the residing intestinal microbial community, which results in a large variability between the test subjects, the exact mechanisms of their protective effects are still under investigation. To this end, simplified cell culture systems have been used to decrease the inter-individual variability in mechanistic studies. In this review, we will discuss the different cell culture models that have been used so far for polyphenol research in the context of cardiovascular diseases. We will also review the current trends in cell culture research, including co-culture methodologies. Finally, we will discuss the potential of these advanced models to screen for cardiovascular effects of the large pool of bioactive polyphenols present in foods and their metabolites.

Tea Catechins Protect Goat Skeletal Muscle against H₂O₂-Induced Oxidative Stress by Modulating Expression of Phase 2 Antioxidant Enzymes

To study the mechanisms of tea catechins (TCs) in goat muscles against oxidative stress, skeletal muscle cells (SMCs) induced by H2O2 or not were incubated with TCs or 3H-1,2-dithiole-3-thione (D3T) and were defined as H2O2, H2O2D3T, H2O2TC, D3T, and TC treatments, respectively. Results showed that, similar to effects of D3T, TCs regulated mRNA and protein expression of antioxidant enzymes by suppressing Keap1 protein expression in SMCs from 1.58 ± 0.12 to 0.71 ± 0.21 and 1.03 ± 0.11 in H2O2TC and TC groups, respectively; however, effects differed in oxidative condition of cells and among enzymes. In stressed cells, TCs increased catalase and glutathione S-transferases (GST) activities (P < 0.001), whereas both enzymes' activities decreased (P < 0.001) to 2.97 ± 0.37 U/mg protein or 42.1 ± 1.85 mU/mg protein, respectively, in unstressed SMCs. Subsequently, an in vivo experiment in goats fed grain supplemented with TCs or D3T following infusion with H2O2 was conducted to further verify mechanisms of TC action. As seen in vitro, TCs reduced Keap1 protein expression (P < 0.001) from 2.11 ± 0.37 to 1.34 ± 0.13 and 1.43 ± 0.23 in H2O2TC and TC groups, respectively, in muscle. However, dietary TCs increased plasma CuZn superoxide dismutase and GST activities (P < 0.001) regardless of oxidative stress. Moreover, feeding TCs to goats under both conditions increased meat color and tenderness (P ≤ 0.001). In conclusion, TCs protected goat muscles against oxidative stress and subsequently improved meat quality by modulating phase 2 antioxidant enzymes and Keap1 expression.

Role of dietary pro-oxidants in the maintenance of health and resilience to oxidative stress

The average length of human life is increasing, but so does the incidence of age- and lifestyle-related diseases. Improving diet and lifestyle is a key strategy for lifelong health and underlying mechanisms may well include increasing resilience pathways. The purpose of this review is to highlight and evaluate novel mechanisms by which dietary pro-oxidants, including bioactive phytochemicals and fatty acids, increase reactive oxygen species (ROS) concentrations just enough to activate transcription factor activation of nuclear factor erythroid 2 related factor 2 (Nrf-2) and heat shock factor (HSF), leading to an increase in levels of antioxidant enzymes and heat shock proteins that protect against the damaging effects of ROS. An increasing number of in vivo studies have now shown that dietary pro-oxidant compounds can increase the production of such resilience products. In most studies, dietary pro-oxidants normalized levels of antioxidant enzymes that were decreased by a range of different challenges, rather than raising levels of resilience products per se. Also, it is important to consider that the antioxidant response can be different for different organs. For future studies, however, the measurement of resilience markers may significantly improve our ability to prove the efficacy by which dietary bioactives with pro-oxidant capacities improve lifelong health.

Purified anthocyanins from bilberry and black currant attenuate hepatic mitochondrial dysfunction and steatohepatitis in mice with methionine and choline deficiency

The berries of bilberry and black currant are a rich source of anthocyanins, which are thought to have favorable effects on nonalcoholic steatohepatitis (NASH). This study was designed to examine whether purified anthocyanins from bilberry and black currant are able to limit the disorders related to NASH induced by a methionine-choline-deficient (MCD) diet in mice. The results showed that treatment with anthocyanins not only alleviated inflammation, oxidative stress, steatosis, and even fibrosis but also improved depletion of mitochondrial content and damage of mitochondrial biogenesis and electron transfer chain developed concomitantly in the liver of mice fed the MCD diet. Furthermore, anthocyanins treatment promoted activation of AMP-activated protein kinase (AMPK) and expression of peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α). These data provide evidence that anthocyanins possess significant protective effects against NASH and mitochondrial defects in response to a MCD diet, with a mechanism maybe through affecting the AMPK/PGC-1α signaling pathways.

Induction of Nrf2 and metallothionein as a common mechanism of hepatoprotective medicinal herbs

Many Chinese medicines have the potential to be hepatoprotective and therefore can be used to treat acute and chronic liver diseases. The challenge is to identify the molecular target for their protective mechanism. This study investigated the induction of nuclear factor-erythroid 2(NF-E2)-related factor 2 (Nrf2) antioxidant genes and metallothionein as a common mechanism of hepatoprotective effects of Chinese medicines such as Piper puberulum. Mice were pretreated with Piper puberulum extract (PPE, 500 mg/kg, po) or vehicles for seven days, followed by intoxication with CCl 4 (25 μl/kg, ip for 16 h), D-galactosamine (800 mg/kg, ip for 8 h), or acetaminophen (400 mg/kg, ip for 8 h). Hepatotoprotection was evaluated by serum enzyme activities and histopathology. To determine the mechanism of protection, mice were given PPE (250-1000 mg/kg, po for seven days) and livers were collected to quantify the expression of Nrf2-targeted genes and metallothionein. Nrf2-null mice were also used to determine the role of Nrf2 in PPE-mediated hepatoprotection.PPE pretreatment protected against the hepatotoxicity produced by CCl 4, D-galactosamine, and acetaminophen, as evidenced by decreased serum enzyme activities and ameliorated liver lesions. PPE treatment increased the expression of hepatic Nrf2, NAD(P)H:quinone oxidoreductase1 (Nqo1), heme oxygenase-1 (Ho-1), glutamate-cysteine ligases (Gclc), and metallothionein (MT), at both transcripts and protein levels. PPE protected wild-type mice from CCl 4 and acetaminophen hepatotoxicity, but not Nrf2-null mice, fortifying the Nrf2-dependent protection. In conclusion, induction of the Nrf2 antioxidant pathways and metallothionein appears to be a common mechanism for hepatoprotective herbs such as PPE.

The protective role of antioxidants in the defence against ROS/RNS-mediated environmental pollution

Overproduction of reactive oxygen and nitrogen species can result from exposure to environmental pollutants, such as ionising and nonionising radiation, ultraviolet radiation, elevated concentrations of ozone, nitrogen oxides, sulphur dioxide, cigarette smoke, asbestos, particulate matter, pesticides, dioxins and furans, polycyclic aromatic hydrocarbons, and many other compounds present in the environment. It appears that increased oxidative/nitrosative stress is often neglected mechanism by which environmental pollutants affect human health. Oxidation of and oxidative damage to cellular components and biomolecules have been suggested to be involved in the aetiology of several chronic diseases, including cancer, cardiovascular disease, cataracts, age-related macular degeneration, and aging. Several studies have demonstrated that the human body can alleviate oxidative stress using exogenous antioxidants. However, not all dietary antioxidant supplements display protective effects, for example, β-carotene for lung cancer prevention in smokers or tocopherols for photooxidative stress. In this review, we explore the increases in oxidative stress caused by exposure to environmental pollutants and the protective effects of antioxidants.

Puerarin ameliorates carbon tetrachloride-induced oxidative DNA damage and inflammation in mouse kidney through ERK/Nrf2/ARE pathway

Puerarin (PU), a natural flavonoid, has been shown to possess many benefits and medicinal properties. In this study, we evaluated the effect of puerarin on oxidative stress and inflammation in kidney induced by carbon tetrachloride (CCl4) and explored the potential mechanisms underlying this effect. Our results showed that puerarin administration significantly inhibited CCl4-induced kidney injury, which indicated by both diagnostic indicators and histopathological analysis. One of the potential mechanisms of puerarin action was decreased the oxidative stress, as evidenced by decreasing of lipid peroxidation level, increasing of SOD, CAT and GPx activities and GSH level. Puerarin also decreased 8-hydroxy-2-deoxyguanosine (one product of oxidative DNA damage) level and increased the expression levels of NQO1, GST and HO-1 in kidneys of CCl4-treated mice. Moreover, western blot analysis showed that puerarin decreased production of pro-inflammatory markers including iNOS and COX-2 in CCl4-treated mouse kidney. We found that puerarin significantly inhibited the ERK phosphorylation and increased the translocation of Nrf2 from the cytosol to the nuclear fraction, which in turn inactivated NF-κB and the inflammatory cytokines in kidneys of the CCl4-treated mice. Altogether, these results suggest that puerarin could protect the CCl4-induced oxidative stress and inflammation by ERK/Nrf2/ARE pathway.

Dietary anthocyanins as nutritional therapy for nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD), defined by excessive lipid accumulation in the liver, is the hepatic manifestation of insulin resistance and the metabolic syndrome. Due to the epidemics of obesity, NAFLD is rapidly becoming the leading cause of altered liver enzymes in Western countries. NAFLD encompasses a wide spectrum of liver disease ranging from simple uncomplicated steatosis, to steatohepatitis, cirrhosis, and hepatocellular carcinoma. Diet may affect the development of NAFLD either by increasing risk or by providing protective factors. Therefore, it is important to investigate the role of foods and/or food bioactives on the metabolic processes involved in steatohepatitis for preventive strategies. It has been reported that anthocyanins (ACNs) decrease hepatic lipid accumulation and may counteract oxidative stress and hepatic inflammation, but their impact on NAFLD has yet to be fully determined. ACNs are water-soluble bioactive compounds of the polyphenol class present in many vegetable products. Here, we summarize the evidence evaluating the mechanisms of action of ACNs on hepatic lipid metabolism in different experimental setting: in vitro, in vivo, and in human trials. Finally, a working model depicting the possible mechanisms underpinning the beneficial effects of ACNs in NAFLD is proposed, based on the available literature.

Paeoniflorin protects human EA.hy926 endothelial cells against gamma-radiation induced oxidative injury by activating the NF-E2-related factor 2/heme oxygenase-1 pathway

Pulmonary endothelial cells have been demonstrated to have a critical role in the pathogenesis of radiation-induced lung injury. Our preliminary experiments indicated that paeoniflorin protected human EA.hy926 endothelial cells from radiation-induced oxidative injury. This study was designed to confirm the protective effect of paeoniflorin against radiation-induced endothelial cellular damage and to elucidate the underlying mechanisms. Preincubation of EA.hy926 cells with paeoniflorin before γ-radiation resulted in significant inhibition of apoptosis, a decrease in mitochondrial membrane potential and enhanced cell viability. In particular, we showed that paeoniflorin significantly reduced the formation of intracellular reactive oxygen species (ROS), the level of malondialdehyde (MDA) and lactate dehydrogenase (LDH) leakage, and enhanced production of the endogenous antioxidants, glutathione (GSH) and superoxide dismutase (SOD) in EA.hy926 cells. Treatment of these cells with paeoniflorin significantly induced HO-1 expression. Moreover, paeoniflorin promoted the nuclear translocation of nuclear factor erythroid 2 related factor-2 (Nrf-2). The paeoniflorin-induced HO-1 expression was abrogated by Nrf2 siRNA. Furthermore, inhibition of HO-1 with zinc protoporphyrin IX (ZNPP) significantly reversed the protective effect of paeoniflorin against radiation-induced damage in EA.hy926 cells. Our findings confirmed that paeoniflorin protected EA.hy926 cells against radiation-induced injury through the Nrf2/HO-1 pathway.

Effect of New Zealand blueberry consumption on recovery from eccentric exercise-induced muscle damage

Background

Exercise-induced muscle damage (EIMD) is accompanied by localized oxidative stress / inflammation which, in the short-term at least, is associated with impaired muscular performance. Dietary antioxidants have been shown to reduce excessive oxidative stress; however, their effectiveness in facilitating recovery following EIMD is not clear. Blueberries demonstrate antioxidant and anti-inflammatory properties. In this study we examine the effect of New Zealand blueberries on EIMD after strenuous eccentric exercise.

Methods

In a randomized cross-over design, 10 females consumed a blueberry smoothie or placebo of a similar antioxidant capacity 5 and 10 hours prior to and then immediately, 12 and 36 hours after EIMD induced by 300 strenuous eccentric contractions of the quadriceps. Absolute peak and average peak torque across the knee, during concentric, isometric, and eccentric actions were measured. Blood biomarkers of oxidative stress, antioxidant capacity, and inflammation were assessed at 12, 36 and 60 hours post exercise. Data were analyzed using a two-way ANOVA.

Results

A significant (p < 0.001) decrease in isometric, concentric and eccentric torque was observed 12 hours following exercise in both treatment groups. During the 60 hour recovery period, a significant (p = 0.047) interaction effect was seen for peak isometric tension suggesting a faster rate of recovery in the blueberry intervention group. A similar trend was observed for concentric and eccentric strength. An increase in oxidative stress and inflammatory biomarkers was also observed in both treatment groups following EIMD. Although a faster rate of decrease in oxidative stress was observed in the blueberry group, it was not significant (p < 0.05) until 36 hours post-exercise and interestingly coincided with a gradual increase in plasma antioxidant capacity, whereas biomarkers for inflammation were still elevated after 60 hours recovery.

Conclusions

This study demonstrates that the ingestion of a blueberry smoothie prior to and after EIMD accelerates recovery of muscle peak isometric strength. This effect, although independent of the beverage’s inherent antioxidant capacity, appears to involve an up-regulation of adaptive processes, i.e. endogenous antioxidant processes, activated by the combined actions of the eccentric exercise and blueberry consumption. These findings may benefit the sporting community who should consider dietary interventions that specifically target health and performance adaptation.