Cocoa flavonoids protect hepatic cells against high-glucose-induced oxidative stress: relevance of MAPKs

Sustained feeding of a diet high in fat resulted in a decline in the liver's insulin-degrading enzyme levels in association with the induction of oxidative and endoplasmic reticulum stress in adult male rats: Evaluation of 4-phenylbutyric acid

The current study explored the impact of high fat diet (HFD) on hepatic oxidative and endoplasmic reticulum (ER) stress and its insulin degrading enzyme (IDE) content with the injection of 4-phenyl butyric acid (4-PBA) in adult male rats. Following the weaning period, male offspring were distributed among six distinct groups. The corresponding diet was used for 20 weeks, subsequently 4-PBA was administered for three consecutive days. Plasma glucose and insulin levels, HOMA-β (homeostasis model assessment of β-cell), hepatic ER and oxidative stress biomarkers and IDE protein content were assessed. Long-term ingestion of HFD (31 % cow butter) induced oxidative and ER stress in the liver tissue. Accordingly, a rise in the malondialdehyde (MDA) content and catalase enzyme activity and a decrease in the glutathione (GSH) content were detected within the liver of the HFD and HFD + DMSO groups. Consumption of this diet elevated the liver expression of binding immunoglobulin protein (BIP) and C/enhancer-binding protein homologous protein (CHOP) levels while reduced its IDE content. The HOMA-β decreased significantly. The injection of the 4-PBA moderated all the induced changes. Findings from this study indicated that prolonged HFD consumption led to a reduction in plasma insulin levels, likely attributed to pancreatic β cell malfunction, as evidenced by a decline in the HOMA-β index. Also, the HFD appears to have triggered oxidative and ER stress in the liver, along with a decrease in its IDE content.

Inhibition of ALK3-mediated signalling pathway protects against acetaminophen-induced liver injury

Acetaminophen (APAP)-induced liver injury is one of the most prevalent causes of acute liver failure (ALF). We assessed the role of the bone morphogenetic protein (BMP) type I receptors ALK2 and ALK3 in APAP-induced hepatotoxicity. The molecular mechanisms that regulate the balance between cell death and survival and the response to oxidative stress induced by APAP was assessed in cultured human hepatocyte-derived (Huh7) cells treated with pharmacological inhibitors of ALK receptors and with modulated expression of ALK2 or ALK3 by lentiviral infection, and in a mouse model of APAP-induced hepatotoxicity. Inhibition of ALK3 signalling with the pharmacological inhibitor DMH2, or by silencing of ALK3, showed a decreased cell death both by necrosis and apoptosis after APAP treatment. Also, upon APAP challenge, ROS generation was ameliorated and, thus, ROS-mediated JNK and P38 MAPK phosphorylation was reduced in ALK3-inhibited cells compared to control cells. These results were also observed in an experimental model of APAP-induced ALF in which post-treatment with DMH2 after APAP administration significantly reduced liver tissue damage, apoptosis and oxidative stress. This study shows the protective effect of ALK3 receptor inhibition against APAP-induced hepatotoxicity. Furthermore, findings obtained from the animal model suggest that BMP signalling might be a new pharmacological target for the treatment of ALF.

(-)-Epicatechin and colonic metabolite 2,3-dihydroxybenzoic acid, alone or in combination with metformin, protect cardiomyocytes from high glucose/high palmitic acid-induced damage by regulating redox status, apoptosis and autophagy

(-)-Epicatechin (EC) and a main colonic phenolic acid derived from flavonoid intake, 2,3-dihydroxybenzoic acid (DHBA), display antioxidant and antidiabetic activities. Diabetic cardiomyopathy (DCM) is one of the main causes of mortality in patients with diabetes, lacking a suitable treatment. Hyperglycaemia and dyslipidaemia are mainly responsible for oxidative stress and altered apoptosis and autophagy in cardiomyocytes during DCM. In this context, phenolic compounds could be suitable candidates for alleviating DCM, but have scarcely been investigated or their use in combination with antidiabetic drugs. This study evaluates the effects of EC, DHBA and antidiabetic drug metformin (MET), alone or all combined (MIX), on redox status, autophagy and apoptosis in H9c2 cardiomyocytes challenged with high concentrations of glucose (HG) and palmitic acid (PA). Under HG + PA conditions, EC, DHBA, MET and MIX equally improved redox status, reduced apoptosis induction and ameliorated autophagy inhibition. Mechanistically, all treatments alleviated HG + PA-induced oxidative stress by reinforcing antioxidant defences (∼40% increase in glutathione, ∼30% diminution in GPx activity and ∼15% increase in SOD activity) and reducing ROS generation (∼20%), protein oxidation (∼35%) and JNK phosphorylation (∼200%). Additionally, all treatments mitigated HG + PA-induced apoptosis and activated autophagy by decreasing Bax (∼15-25%), caspase-3 (∼20-40%) and p62 (∼20-40%), and increasing Bcl-2, beclin-1 and LC3-II/LC3-I (∼40-60%, ∼15-20%, and ∼25-30%, respectively). JNK inhibition improved protective changes to redox status, apoptosis and autophagy that were observed in EC-, DHBA- and MIX-mediated protection. Despite no additive or synergistic effects being detected when phenolic compounds and MET were combined, these results provide the first evidence for the benefits of EC and DHBA, comparable to those of MET alone, to ameliorate cardiomyocyte damage, that involve an improvement in antioxidant competence, autophagy and apoptosis, these effects being mediated at least by targeting JNK.

Effects of Foods of Mesoamerican Origin in Adipose Tissue and Liver-Related Metabolism

Adipose tissue and liver metabolism play a key role in maintaining body homeostasis; therefore, their impairment conduces a pathological state. Nowadays, occidental lifestyle is a common etiological issue among a variety of chronic diseases, while diet is a unique strategy to prevent obesity and liver metabolism impairment and is a powerful player in the treatment of metabolic-related diseases. Mesoamerican foods are rich in bioactive molecules that enhance and improve adipose tissue and liver performance and represent a prophylactic and therapeutic alternative for disorders related to the loss of homeostasis in the metabolism of these two important tissues.

Cupuaçu extract protects the kidneys of diabetic rats by modulating Nrf2/NF-κB p65 and iNOS

Diabetes is characterized by increased levels of oxidative stress. Its suggested that extract of cupuaçu could improve the antioxidant system in diabetes. The aim was to evaluate the effect of EC on Nrf2/NF-κB p65 in normal and diabetic rats. Male, adult Wistar rats (9-week-old) were distributed in 4 groups: control (CTL) and diabetic (DM) who received water; CTLEC and DMEC who received 1 mL/day of EC (1 g/mL), via gavage for 8 consecutive weeks. The diabetes was inducted with a single intravenous dose of 45 mg/kg streptozotocin. Glycemia and body weight were measured at the beginning and end of the protocol, and the renal tissue was analyzed by Western blot for SOD-1, SOD-2, CAT, GSSG, Nrf2, NF-κB p65, iNOS and 3-NT. Glycemia was reduced in DMEC vs. DM after 8 weeks of EC treatment. There was no difference in body weight of DMEC vs. DM; however, DMEC vs. DM presented increased levels of CAT and Nrf2, with a significant reduction of NF-κB p65, iNOS and 3-NT. Therefore, we suggest that EC could be utilized as a complementary therapy to ameliorate the antioxidant profile via Nrf2 and to delay the evolution of diabetic complications in renal tissue by inflammatory pathway inhibition.

Pathogenetic Pathways in Nonalcoholic Fatty Liver Disease: An Incomplete Jigsaw Puzzle

Nonalcoholic fatty liver disease (NAFLD)-a condition of excess fat accumulation in hepatocytes associated with metabolic dysfunction-has surpassed viral hepatitis to become the most prevalent chronic liver disease worldwide. As of now, only modestly effective pharmacological therapies for NAFLD exist. The uncomplete understanding of the pathophysiology underlying the heterogeneous disease spectrum known as NAFLD remains one of the major obstacles to the development of novel therapeutic approaches. This review compiles current knowledge on the principal signaling pathways and pathogenic mechanisms involved in NAFLD, which are analyzed in relation to its main pathological hallmarks (ie, hepatic steatosis, steatohepatitis, and liver fibrosis).

From Cocoa to Chocolate: Effect of Processing on Flavanols and Methylxanthines and Their Mechanisms of Action

Despite the health benefits associated with the ingestion of the bioactive compounds in cocoa, the high concentrations of polyphenols and methylxanthines in the raw cocoa beans negatively influence the taste, confer the astringency and bitterness, and affect the stability and digestibility of the cocoa products. It is, therefore, necessary to process cocoa beans to develop the characteristic color, taste, and flavor, and reduce the astringency and bitterness, which are desirable in cocoa products. Processing, however, affects the composition and quantities of the bioactive compounds, resulting in the modification of the health-promoting properties of cocoa beans and chocolate. In this advanced review, we sought to better understand the effect of cocoa's transformational process into chocolate on polyphenols and methylxanthine and the mechanism of action of the original flavanols and methylxanthines. More data on the cocoa processing effect on cocoa bioactives are still needed for better understanding the effect of each processing step on the final polyphenolic and methylxanthine composition of chocolate and other cocoa products. Regarding the mechanisms of action, theobromine acts through the modulation of the fatty acid metabolism, mitochondrial function, and energy metabolism pathways, while flavanols mainly act though the protein kinases and antioxidant pathways. Both flavanols and theobromine seem to be involved in the nitric oxide and neurotrophin regulation.

A diarylheptanoid compound from Alpinia officinarum Hance ameliorates high glucose-induced insulin resistance by regulating PI3K/AKT-Nrf2-GSK3β signaling pathways in HepG2 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Alpinia officinarum Hance, a perennial natural medicine-food herb, has been traditionally used to treat colds, stomachache, and diabetes for thousands of years. 1,7-Diphenyl-4E-en-3-heptanone (DPH5), a diarylheptanoid isolated from the rhizome of A. officinarum has been reported to be safe and to have antioxidant and hypoglycemic effects, suggesting its potential in the treatment of insulin resistance (IR).

AIM OF THE STUDY

Aim of to investigate the protective effect of DPH5 on IR and elucidate its underlying mechanism of action.

MATERIALS AND METHODS

HepG2 cells were used as the research objects. Glucose uptake and reactive oxygen species (ROS) levels in high glucose-induced insulin-resistant HepG2 cells were assessed using flow cytometry. Glucose consumption and the levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were analyzed using the corresponding assay kits. The expression of mRNA and proteins related to insulin signaling, glucose metabolism, and antioxidant factor, including insulin receptor substrate-1 (IRS1), phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), translocation of glucose transporter-4, glycogen synthase kinase-3β (GSK3β), glucokinase (GCK), pyruvate kinase (PK), phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase (G6Pase), nuclear factor-erythroid 2 related factor 2 (Nrf2), heme oxygenase-1 (HO-1), NADPH quinoneoxidoreductase (NQO1), and glutathione peroxidase (GSH-Px) was determined using real-time quantitative polymerase chain reaction and western blotting. Furthermore, molecular docking was performed to determine the spatial mechanism of DPH5 on the key targets PI3K, AKT, Nrf2, and GSK3β.

RESULTS

DPH5 could improve IR that manifested as increased glucose uptake and glucose consumption in insulin-resistant HepG2 cells. Moreover, DPH5 could enhance antioxidant capacity by activating Nrf2/HO-1 elements, including increasing Nrf2, HO-1, SOD, NQO1, and GSH-Px expression and reducing MDA, ROS, and JNK levels, thereby improving oxidative stress and ultimately alleviating IR. Additionally, DPH5 could promote the expression of IRS1, PI3K, AKT, GSK3β, GCK, and PK, and downregulate the expression of PEPCK and G6pase, thereby accelerating glucose utilization and enhancing insulin sensitivity. The mechanism underlying the effect of DPH5 in alleviating IR was related to the PI3K/AKT- and Nrf2/HO-1-mediated regulation of the GSK3β signaling pathway, and the results were further confirmed using the specific inhibitors LY294002 and ML385. Results from molecular docking indicated that there were different regulatory sites and interacting forces between DPH5 and PI3K, AKT, Nrf2, and GSK3β; however, the binding force was relatively strong.

CONCLUSIONS

DPH5 improved oxidative stress and glucose metabolism via modulating the PI3K/AKT-Nrf2-GSK3β pathway, thereby ameliorating IR. Overall, our findings suggest the potential of DPH5 as a natural medicine to treat type-2 diabetes mellitus.

Preventive Effect of Cocoa Flavonoids via Suppression of Oxidative Stress-Induced Apoptosis in Auditory Senescent Cells

Presbycusis or Age-related hearing loss (ARHL) is a sensorineural hearing loss that affects communication, leading to depression and social isolation. Currently, there are no effective treatments against ARHL. It is known that cocoa products have high levels of polyphenol content (mainly flavonoids), that are potent anti-inflammatory and antioxidant agents with proven benefits for health. The objective is to determine the protective effect of cocoa at the cellular and molecular levels in Presbycusis. For in vitro study, we used House Ear Institute-Organ of Corti 1 (HEI-OC1), stria vascularis (SV-k1), and organ of Corti (OC-k3) cells (derived from the auditory organ of a transgenic mouse). Each cell line was divided into a control group (CTR) and an H₂O₂ group (induction of senescence by an oxygen radical). Additionally, every group of every cell line was treated with the cocoa polyphenolic extract (CPE), measuring different markers of apoptosis, viability, the activity of antioxidant enzymes, and oxidative/nitrosative stress. The data show an increase of reactive oxidative and nitrogen species (ROS and RNS, respectively) in senescent cells compared to control ones. CPE treatment effectively reduced these high levels and correlated with a significant reduction in apoptosis cells by inhibiting the mitochondrial-apoptotic pathway. Furthermore, in senescence cells, the activity of antioxidant enzymes (Superoxide dismutase, SOD; Catalase, CAT; and Glutathione peroxidase, GPx) was recovered after CPE treatment. Administration of CPE also decreased oxidative DNA damage in the auditory senescent cells. In conclusion, CPE inhibits the activation of senescence-related apoptotic signaling by decreasing oxidative stress in auditory senescent cells.

Metabolic regulation of (-)-epicatechin and the colonic metabolite 2,3-dihydroxybenzoic acid on the glucose uptake, lipid accumulation and insulin signalling in cardiac H9c2 cells

Epicatechin (EC) and main colonic phenolic acids derived from flavonoid intake have been suggested to exert healthful effects, although their mechanism of action remains unknown. Heart damage is highly prevalent in metabolic diseases, and the failure of this organ is a major cause of death worldwide. In this study, the modulation of the energy metabolism and insulin signalling by the mentioned compounds in cardiac H9c2 cells was evaluated. Incubation of cells with EC (1-20 μM) and 2,3-dihydroxybenzoic acid (DHBA, 10 μM) reduced glucose uptake, and both compounds decreased lipid accumulation at concentrations higher than 0.5 μM. EC and DHBA also increased the tyrosine phosphorylated and total insulin receptor (IR) levels, and activated the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway in cardiac H9c2 cells. Interestingly, EC and DHBA did not modify glucose transporters (SGLT-1 and GLUT-1) levels, and increased GLUT-4 values. In addition, EC and DHBA decreased cluster of differentiation 36 (CD36) and fatty acid synthase (FAS) values, and enhanced carnitine palmitoyl transferase 1 (CPT1) and proliferator activated receptor α (PPARα) levels. By using specific inhibitors of AKT and 5'-AMP-activated protein kinase (AMPK), the participation of both proteins in EC- and DHBA-mediated regulation on glucose uptake and lipid accumulation was shown. Taken together, EC and DHBA modulate glucose uptake and lipid accumulation via AKT and AMPK, and reinforce the insulin signalling by activating key proteins of this pathway in H9c2 cells.

Theobroma cacao improves bone growth by modulating defective ciliogenesis in a mouse model of achondroplasia

A gain-of-function mutation in the fibroblast growth factor receptor 3 gene (FGFR3) results in achondroplasia (ACH), the most frequent form of dwarfism. Constitutive activation of FGFR3 impairs bone formation and elongation and many signal transduction pathways. Identification of new and relevant compounds targeting the FGFR3 signaling pathway is of broad importance for the treatment of ACH, and natural plant compounds are prime drug candidate sources. Here, we found that the phenolic compound (-)-epicatechin, isolated from Theobroma cacao, effectively inhibited FGFR3's downstream signaling pathways. Transcriptomic analysis in an Fgfr3 mouse model showed that ciliary mRNA expression was modified and influenced significantly by the Indian hedgehog and PKA pathways. (-)-Epicatechin is able to rescue mRNA expression impairments that control both the structural organization of the primary cilium and ciliogenesis-related genes. In femurs isolated from a mouse model (Fgfr3^Y367C/+) of ACH, we showed that (-)-epicatechin eliminated bone growth impairment during 6 days of ex vivo culture. In vivo, we confirmed that daily subcutaneous injections of (-)-epicatechin to Fgfr3^Y367C/+ mice increased bone elongation and rescued the primary cilium defects observed in chondrocytes. This modification to the primary cilia promoted the typical columnar arrangement of flat proliferative chondrocytes and thus enhanced bone elongation. The results of the present proof-of-principle study support (-)-epicatechin as a potential drug for the treatment of ACH.

Roles of Oxidative Stress in the Male Reproductive System: Potential of Antioxidant Supplementation for Infertility Treatment

The decline of fertility in modern society is a serious worldwide concern, and the reasons behind it are complex and difficult to unveil. The fact that a big percentage of infertility cases remain diagnosed as idiopathic, turn the strategies to treat such conditions very limited. Nevertheless, one must agree that keeping the oxidative balance of the reproductive tissues should be one of the first lines of treatment for infertile patients. As reported, 30-80% of male infertile individuals present high levels of prooxidant species in the seminal fluid. Thus, antioxidant therapies, which consist of dietary supplementation therapy with one or more antioxidant compound, remain the first step in the treatment of male infertility. Nevertheless, the efficacy of such therapies is variable between individuals. The most common prescribed antioxidants are carnitines and vitamins C and E, but recently phytochemical quercetin has emerged as a potential compound for the treatment of oxidative stress in the male reproductive system. Although there are several animals' evidence about the great potential of quercetin for the treatment of infertility, clinical trials on this subject remain scarce.

Epicatechin ameliorative effects on methotrexate-induced hepatotoxicity in mice

BACKGROUND

Due to the fact that methotrexate is widely used both as an immunosuppressive drug and as a chemotherapy agent, many studies are needed to reduce the side effects of this drug on non-target organs.

PURPOSE

This study was designed to investigate the effects of epicatechin (Epi) on MTX (methotrexate)-induced hepatotoxicity in mice.

RESEARCH DESIGN

After 1 week for adaptation, we randomly divided 42 male Naval Medical Research Institute mice into six groups: (I) control; (II) Epi (100 mg/kg, po); (III) MTX (20 mg/kg, i.p.) on the fifth day; and (IV, V, and VI) Epi (25, 50, and 100 mg/kg, po) + MTX (20 mg/kg, i.p.) on the fifth day. At day 10, the mice were sacrificed and serum factors, oxidative stress markers, and inflammatory cytokines were measured.

RESULTS

MTX increased activity level of serum enzymes (alanine aminotransferase and aspartate aminotransferase), lipid peroxidation marker (malondialdehyde), and inflammatory factors including interleukin-1 beta, tumor necrosis factor-alpha, and nitric oxide. Furthermore, MTX decreased glutathione level and activity level of catalase, superoxide dismutase, and glutathione peroxidase. Epi was able to reduce the destructive effects of oxidative/antioxidant system imbalance and inflammatory reactions and also histopathological damage in MTX intoxicated mice. Epi pretreatment reduced liver dysfunction by improving the antioxidant defense system, anti-inflammatory effects, and alleviation of histopathological damage in MTX hepatotoxicity.

CONCLUSIONS

Accordingly, Epi can be used as a therapeutic agent in hepatotoxicity associated with MTX chemotherapy.

Hepatoprotective Plants from Bangladesh: A Biophytochemical Review and Future Prospect

Liver diseases are quite prevalant in many densely populated countries, including Bangladesh. The liver and its hepatocytes are targeted by virus and microbes, as well as by chemical environmental toxicants, causing wide-spread disruption of metabolic fuctions of the human body, leading to death from end-stage liver diseases. The aim of this review is to systematically explore and record the potential of Bangladeshi ethnopharmacological plants to treat liver diseases with focus on their sources, constituents, and therapeutic uses, including mechanisms of actions (MoA). A literature survey was carried out using Pubmed, Google Scholar, ScienceDirect, and Scopus databases with articles reported until July, 2020. A total of 88 Bangladeshi hepatoprotective plants (BHPs) belonging to 47 families were listed in this review, including Euphorbiaceae, Cucurbitaceae, and Compositae families contained 20% of plants, while herbs were the most cited (51%) and leaves were the most consumed parts (23%) as surveyed. The effect of BHPs against different hepatotoxins was observed via upregulation of antioxidant systems and inhibition of lipid peroxidation which subsequently reduced the elevated liver biomarkers. Different active constituents, including phenolics, curcuminoids, cucurbitanes, terpenoids, fatty acids, carotenoids, and polysaccharides, have been reported from these plants. The hepatoameliorative effect of these constituents was mainly involved in the reduction of hepatic oxidative stress and inflammation through activation of Nrf2/HO-1 and inhibition of NF-κB signaling pathways. In summary, BHPs represent a valuable resource for hepatoprotective lead therapeutics which may offer new alternatives to treat liver diseases.

Aqueous Extract of Cocoa Phenolic Compounds Protects Differentiated Neuroblastoma SH-SY5Y Cells from Oxidative Stress

Cocoa is a rich source of polyphenols, especially flavanols and procyanidin oligomers, with antioxidant properties, providing protection against oxidation and nitration. Cocoa phenolic compounds are usually extracted with methanol/ethanol solvents in order to obtain most of their bioactive compounds; however, aqueous extraction seems more representative of the physiological conditions. In this study, an aqueous extract of cocoa powder has been prepared and chemically characterized, and its potential protective effect against chemically-induced oxidative stress has been tested in differentiated human neuroblastoma SH-SY5Y cells. Neuronal-like cultured cells were pretreated with realistic concentrations of cocoa extract and its major monomeric flavanol component, epicatechin, and then submitted to oxidative stress induced by a potent pro-oxidant. After one hour, production of reactive oxygen species was evaluated by two different methods, flow cytometry and in situ fluorescence by a microplate reader. Simultaneously, reduced glutathione and antioxidant defense enzymes glutathione peroxidase and glutathione reductase were determined and the results used for a comparative analysis of both ROS (reactive oxygen species) methods and to test the chemo-protective effect of the bioactive products on neuronal-like cells. The results of this approach, never tested before, validate both analysis of ROS and indicate that concentrations of an aqueous extract of cocoa phenolics and epicatechin within a physiological range confer a significant protection against oxidative insult to neuronal-like cells in culture.

The effects of cocoa flavanols on indices of muscle recovery and exercise performance: a narrative review

Exercise-induced muscle damage (EIMD) is associated with oxidative stress and inflammation, muscle soreness, and reductions in muscle function. Cocoa flavanols (CF) are (poly)phenols with antioxidant and anti-inflammatory effects and thus may attenuate symptoms of EIMD. The purpose of this narrative review was to collate and evaluate the current literature investigating the effect of CF supplementation on markers of exercise-induced oxidative stress and inflammation, as well as changes in muscle function, perceived soreness, and exercise performance. Acute and sub-chronic intake of CF reduces oxidative stress resulting from exercise. Evidence for the effect of CF on exercise-induced inflammation is lacking and the impact on muscle function, perceived soreness and exercise performance is inconsistent across studies. Supplementation of CF may reduce exercise-induced oxidative stress, with potential for delaying fatigue, but more evidence is required for any definitive conclusions on the impact of CF on markers of EIMD.

Prostatic alterations associated to early weaning and its relation with cocoa powder supplementation. Experimental study in adult wistar rats

Early weaning can predispose the offspring to greater risk of developing chronic diseases in adulthood. It is believed that the consumption of functional foods is able to prevent these effects. The aim of this study is to evaluate the effects of maternal and postnatal cocoa powder supplementation on body mass, metabolism, and morphology of the prostate of early weaned Wistar rats. The animals were divided into four experimental groups according to lactation time (21 or 18 days, n=6, each) as follows: control group (C), cocoa control group (CCa), early weaning group (EW), and cocoa early weaning group (EWCa). The animals were euthanized at 90 days of age. Serum biochemical analysis and prostate histomorphometric evaluation were performed. The animals supplemented with cocoa powder were heavier than their respective controls (p <0.05), although with no difference in food intake among the groups. Likewise, these same groups showed a reduction in the serum glucose in relation to C and EW groups (p <0.0001). With respect to the prostate, there was no difference in smooth muscle and lumen area densities, while the EW group had a lower epithelial height and a higher percentage of mast cells than the C group (p <0.05). On the other hand, the EWCa group managed to reverse these parameters, leveling with the controls. Early weaning resulted in hyperglycemia and important morphological changes in the prostate. In contrast, dietary supplementation with cocoa powder attenuated these effects on the metabolism and prostatic histoarchitecture, proving to be a good nutritional treatment strategy.

Traceability of polyphenols in cocoa during the postharvest and industrialization processes and their biological antioxidant potential

Noncommunicable diseases, the leading cause of mortality around the world, are responsible for approximately 75% of premature adult deaths (ages 30-69). To tackle this issue, a healthy diet based on functional foods, including cocoa and its derivatives, has been increasingly promoted. The polyphenols present in cocoa have been of interest due to their antioxidant potential and their possible protective role in the context of noncommunicable diseases, such as diabetes and cardiovascular conditions. However, during cocoa postharvest and industrialization, the concentration of these bioactive compounds is reduced, possibly affecting their health-promoting properties. Therefore, this paper reviews in the literature in this field to find the total polyphenol content in cocoa during the postharvest and industrialization processes in order to define concentration ranges as a reference point for future research. In addition, it discusses in vitro and in vivo studies into the biological antioxidant potential of cocoa and its derivatives. This review covers publications in indexed databases from 2010 to 2020, their data were processed and presented here using box plots. As a result, we identified the concentration ranges of polyphenols depending on the type of matrix, treatment and country, as well as their relationship with the main bioactive compounds present in cocoa that are associated with their possible antioxidant biological potential and health-related benefits.

Molecular Determinants of the Cardiometabolic Improvements of Dietary Flavanols Identified by an Integrative Analysis of Nutrigenomic Data from a Systematic Review of Animal Studies

SCOPE

Flavanols are important polyphenols of the human diet with extensive demonstrations of their beneficial effects on cardiometabolic health. They contribute to preserve health acting on a large range of cellular processes. The underlying mechanisms of action of flavanols are not fully understood but involve a nutrigenomic regulation.

METHODS AND RESULTS

To further capture how the intake of dietary flavanols results in the modulation of gene expression, nutrigenomics data in response to dietary flavanols obtained from animal models of cardiometabolic diseases have been collected and submitted to a bioinformatics analysis. This systematic analysis shows that dietary flavanols modulate a large range of genes mainly involved in endocrine function, fatty acid metabolism, and inflammation. Several regulators of the gene expression have been predicted and include transcription factors, miRNAs and epigenetic factors.

CONCLUSION

This review highlights the complex and multilevel action of dietary flavanols contributing to their strong potential to preserve cardiometabolic health. The identification of the potential molecular mediators and of the flavanol metabolites driving the nutrigenomic response in the target organs is still a pending question which the answer will contribute to optimize the beneficial health effects of dietary bioactives.

Dietary Flavonoids and Insulin Signaling in Diabetes and Obesity

Type 2 diabetes (T2D) and obesity are relevant worldwide chronic diseases. A common complication in both pathologies is the dysregulation of the insulin-signaling pathway that is crucial to maintain an accurate glucose homeostasis. Flavonoids are naturally occurring phenolic compounds abundant in fruits, vegetables and seeds. Rising evidence supports a role for the flavonoids against T2D and obesity, and at present, these compounds are considered as important potential chemopreventive agents. This review summarizes in vitro and in vivo studies providing data related to the effects of flavonoids and flavonoid-rich foods on the modulation of the insulin route during T2D and obesity. Notably, few human studies have evaluated the regulatory effect of these phenolic compounds at molecular level on the insulin pathway. In this context, it is also important to note that the mechanism of action for the flavonoids is not fully characterized and that a proper dosage to obtain a beneficial effect on health has not been defined yet. Further investigations will contribute to solve all these critical challenges and will enable the use of flavonoids to prevent, delay or support the treatment of T2D and obesity.

Neferine Exerts Antioxidant and Anti-Inflammatory Effects on Carbon Tetrachloride-Induced Liver Fibrosis by Inhibiting the MAPK and NF-κB/IκBα Pathways

Reversible liver fibrosis is the consequence of diverse liver injuries. Oxidative stress combined with inflammation is the primary cause of carbon tetrachloride- (CCl₄-) induced liver fibrosis. Neferine is a bibenzyl isoquinoline alkaloid, which has strong anti-inflammatory and antioxidant properties. The present study attempted to find its antiliver fibrosis effect and explore the potential mechanism to relieve oxidative stress and inflammation in rats with CCl₄-induced liver fibrosis. Herein, we found that neferine noticeably mitigated fibrosis and improved liver function. Furthermore, neferine increased the activity of antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and catalase (CAT), but decreased the level of malondialdehyde (MDA). Neferine also decreased the levels of alpha-smooth muscle actin (α-SMA), transforming growth factor β1 (TGF-β1), and inflammatory factors. These results may demonstrate that neferine could effectively inhibit oxidative stress and inflammation in liver fibrosis. To account for the potential mechanism by which neferine relieves oxidative stress and inflammation in liver fibrosis rats, immunohistochemistry analyses and western blotting were performed. The results showed that neferine inhibited the mitogen-activated protein kinase (MAPK) pathway, as evidenced by the reduced phosphorylation of p38 MAPK, ERK 1/2, and JNK. And it inhibited the nuclear factor- (NF-) κB/IκBα pathway, as evidenced by preventing the translocation of NF-κB into nuclei. Our findings indicated a protective role for neferine, acting as an antioxidant and anti-inflammatory agent in CCl₄-induced liver fibrosis.

Natural Nrf2 Activators from Juices, Wines, Coffee, and Cocoa

Juices, wine, coffee, and cocoa are rich sources of natural polyphenolic compounds that have potent antioxidant activities proven by in vitro and in vivo studies. These polyphenolic compounds quench reactive oxygen and nitrogen species (RONS) or reactive free radicals and act as natural antioxidants which are also able to protect against reactive oxygen species (ROS)-mediated oxidative damage, which elevates cellular antioxidant capacity to induce antioxidant defense mechanisms by modulating transcription factors. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a transcription factor encoded in humans. It is activated as a result of oxidative stress and induces the expression of its target genes. This is one of the most important cellular defense mechanisms against oxidative stress. However, the oxidative stress alone is not enough to activate Nrf2. Hence phytochemicals, especially polyphenolics, act as natural Nrf2 activators. Herein, this review discusses the natural products identified in juices, coffee, cocoa and wines that modulate Nrf2 activity in cellular systems.

Effect of Cocoa and Cocoa Products on Cognitive Performance in Young Adults

Increasing evidence support a beneficial role of cocoa and cocoa products on human cognition, particularly in aging populations and patients at risk. However, thorough reviews on the efficacy of cocoa on brain processes in young adults do not exist precisely due to the limited number of studies in the matter. Thus, the aim of this study was to summarize the findings on the acute and chronic effects of cocoa administration on cognitive functions and brain health in young adults. Web of Science and PubMed databases were used to search for relevant trials. Human randomized controlled studies were selected according to PRISMA guidelines. Eleven intervention studies that involved a total of 366 participants investigating the role of cocoa on cognitive performance in children and young adults (average age ≤ 25 years old) were finally selected. Findings from individual studies confirm that acute and chronic cocoa intake have a positive effect on several cognitive outcomes. After acute consumption, these beneficial effects seem to be accompanied with an increase in cerebral blood flow or cerebral blood oxygenation. After chronic intake of cocoa flavanols in young adults, a better cognitive performance was found together with increased levels of neurotrophins. This systematic review further supports the beneficial effect of cocoa flavanols on cognitive function and neuroplasticity and indicates that such benefits are possible in early adulthood.

The sweet side of dark chocolate for chronic kidney disease patients

Chocolate is a widely appreciated foodstuff with historical appreciation as a food from the gods. In addition to its highly palatable taste, it is a rich source of (poly)phenolics, which have several proposed salutogenic effects, including neuroprotective anti-inflammatory, anti-oxidant and cardioprotective capabilities. Despite the known benefits of this ancient foodstuff, there is a paucity of information on the effects of chocolate in the context of chronic kidney disease (CKD). This review focusses on the potential salutogenic contribution of chocolate intake, to mitigate inflammatory and oxidative burden in CKD, its potential, for cardiovascular protection and on the maintenance of diversity in gut microbiota, as well as clinical perspectives, on regular chocolate intake by CKD patients.

Microencapsulation as a tool to counteract the typical low bioavailability of polyphenols in the management of diabetes

Polyphenols are secondary metabolites widely distributed in many plant foods, such a tea, coffee, chocolate and fruits. The consumption of these compounds is related to the improvement or amelioration of many diseases, including diabetes. Nevertheless, the great barrier to the therapeutic use of polyphenols is the low bioavailability of these compounds once ingested. For that reason, the encapsulation of polyphenols in different matrices may protect them from digestion and improve their release and subsequent absorption to obtain target-specific health effects. Some studies have reported the beneficial effect of encapsulation to increase both bioavailability and bioaccessibility. However, these works have mostly been carried out in vitro and few studies are specifically addressed at improving diabetes. In the current work, an overview of the knowledge related to nanoparticles and their use in the diabetic condition has been reviewed.

Cardioprotective Efficacy of Silymarin Liquisolid in Isoproterenol Prompted Myocardial Infarction in Rats

Myocardial infarction (MI) is the principal cause of death in many countries. Silymarin (SM) is a herbal antioxidant and can be efficiently used in preventing cardiovascular diseases (CVDs). The study is aimed to enhance the absorption rate and biological activity of SM by using liquisolids besides investigating the cardioprotective activity of SM and its selected liquisolid formula against isoproterenol prompted cardiotoxicity in rats. Eight formulae were prepared according to (2³) full-factorial design. The effect of viscosity increasing agent type and concentration, as well as the carrier/coat ratio on the dissolution rate and angle of repose were studied. All formulae were tested for content uniformity, micromeritic properties, dissolution performance besides the evaluation of its physicochemical properties, and scanning electron microscopy (SEM). Based on the factorial design outcomes, the highest desirability was obtained from F3 with excipient ratio value (R) of 20%, dissolution rate at Q_5 min of 26.9%, and angle of repose of 19. Oral administration of F3 liquisolid and SM revealed a significant protective efficacy against the modification of cardiac plasma markers, brain natriuretic peptide (BNP), interleukin-10 (IL-10), vascular endothelial growth factor (VEGF), and transforming growth factor (TGF)-β1 besides cardiac superoxide dismutase (SOD), malondialdehyde (MDA), and total protein kinase-1 (Akt-1) levels. Additionally, they minimized cardiac inducible nitric oxide synthase (iNOS), microRNA-34a (miR-34a), and p38 mitogen-activated protein kinase (p38-MAPK) levels. In conclusion, F3 liquisolid compact possessed an overall pronounced results over pure SM reckoned to its enhanced solubility and efficacy.

Effects of nitrate on development and thyroid hormone signaling pathway during Bufo gargarizans embryogenesis

Nitrate is known to disrupt the thyroid hormone, which is essential for the metamorphosis of amphibians. However, few studies are focused on the effects of nitrate on the maternal thyroid hormone in early amphibian embryos. We aimed to determine the impact of nitrate on maternal thyroid hormone signaling pathway in Bufo gargarizans embryos. B. gargarizans embryos were exposed to different concentrations of nitrate-nitrogen (NO3-N) for 7 days. High concentration of NO3-N (50, 100, and 200 mg/L) could induce embryonic malformation and influence the development of embryos. In addition, maternal T4 and components of the thyroid hormone (TH) signaling pathway were detected by ELISA and RNA-seq, respectively. The expression levels of mRNA related to thyroid hormone and oxidative stress were affected in the early developing embryos in all NO3-N treatment groups. However, the T4 levels and the spatial expression patterns of type II iodothyronine deiodinase (D2), type III iodothyronine deiodinase (D3), thyroid hormone receptor α (TRα), and thyroid hormone receptor β (TRβ) mRNA were not changed by nitrate. In conclusion, the results of our study highlight the crucial role of the maternal thyroid hormone signaling pathway in normal embryonic development, and the adverse effects of nitrate on the expression levels of mRNA related to thyroid hormone signaling pathway and oxidative stress in B. gargarizans embryos.

Role of flavonoids in thrombotic, cardiovascular, and inflammatory diseases

The failure of mechanisms of natural anti-coagulation either due to genetic impairment or due to severe external injuries may result in a condition called thrombosis. This is believed to be the primary cause for a variety of life-threatening conditions such as: heart attack, stroke, pulmonary embolism, thrombophlebitis, and deep venous thrombosis (DVT). The growing number of these incidents requires an alternative anti-coagulant or anti-thrombotic agent that has minimal side effects and improved efficiency. For decades, plant polyphenols, especially flavonoids, were known for their vital role in preventing various diseases such as cancer. Mitigating excessive oxidative stress caused by reactive oxygen species (ROS) with anti-oxidant-rich flavonoids may reduce the risk of hyper-activation of platelets, cardiovascular diseases (CVD), pain, and thrombosis. Furthermore, flavonoids may mitigate endothelial dysfunction (ED), which generally correlates to the development of coronary artery and vascular diseases. Flavonoids also reduce the risk of atherosclerosis and atherothrombotic disease by inhibiting excessive tissue factor (TF) availability in the endothelium. Although the role of flavonoids in CVD is widely discussed, to the best of our knowledge, their role as anti-thrombotic lead has not been discussed. This review aims to focus on the biological uses of dietary flavonoids and their role in the treatment of various coagulation disorders, and may provide some potential lead to the drug discovery process in this area.

Isoflavone biochanin A, a novel nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element activator, protects against oxidative damage in HepG2 cells

Isoflavones are one group of the major flavonoids and possess multiple biological activities due to their antioxidant properties. However, a clear antioxidant mechanism of dietary isoflavones is still remained to be answered. In this study, the effects of isoflavones on the nuclear factor E2-related factor 2 (Nrf2)-antioxidant response element (ARE) signaling pathway and the underlying molecular mechanisms were investigated. Results showed that isoflavones are potential Nrf2-ARE activators while their activities were structure dependent. Biochanin A (BCA), an O-methylated isoflavone with low direct antioxidant activity, can effectively protect HepG2 cells against tert-butyl hydroperoxide (t-BHP)-induced oxidative damage via activation of the Nrf2 signaling, and thereby the induction of downstream cytoprotective enzymes including NAD(P)H quinone oxidoreductase-1, heme oxygenasae-1, and glutamate-cysteine ligase catalytic subunit. A molecular docking study revealed that BCA could directly bind into the pocket of Kelch-like erythroid cell-derived protein with CNC homology (ECH)-associated protein 1 (Keap1), a cytoplasmic suppressor of Nrf2, to facilitate Nrf2 activation. The upstream mitogen-activated protein kinase (MAPK) pathways were also involved in the activation of Nrf2 signaling. These findings indicate that the protective actions of dietary isoflavones against oxidative damage may be at least partly due to their ability to enhance the intracellular antioxidant response system by modulating the Nrf2-ARE signaling pathway.

Cocoa Flavanols: Natural Agents with Attenuating Effects on Metabolic Syndrome Risk Factors

The interest in cacao flavanols is still growing, as bioactive compounds with potential benefits in the prevention of chronic diseases associated with inflammation, oxidative stress and metabolic disorders. Several analytical methodologies support that the flavanols in cacao-derived products can be absorbed, have bioactive properties, and thus can be responsible for their beneficial effects on human health. However, it must be considered that their biological actions and underlying molecular mechanisms will depend on the concentrations achieved in their target tissues. Based on the antioxidant properties of cacao flavanols, this review focuses on recent advances in research regarding their potential to improve metabolic syndrome risk factors. Additionally, it has included other secondary plant metabolites that have been investigated for their protective effects against metabolic syndrome. Studies using laboratory animals or human subjects represent strong available evidence for biological effects of cacao flavanols. Nevertheless, in vitro studies are also included to provide an overview of these phytochemical mechanisms of action. Further studies are needed to determine if the main cacao flavanols or their metabolites are responsible for the observed health benefits and which are their precise molecular mechanisms.

Peanut skin phenolic extract attenuates hyperglycemic responses in vivo and in vitro

Diabetes affects at least 285 million people globally, and this number continues to increase. Clinical complications include impaired glucose metabolism, hyperglycemia, dyslipidemia, atherosclerosis and non-alcoholic fatty liver disease. Evidence has shown that natural phenolics play a protective effect on both the development and management of type 2 diabetes. This study evaluated effects of the extract from peanut skins containing polyphenols on induced- hyperglycemia using in vivo and in vitro methods. A human hepatocellular liver carcinoma cell line (HepG2) was used to investigate the effect of the peanut skin extract on cell viability after exposure to high glucose concentrations. In vivo, the effect of peanut skin extract on an oral glucose tolerance was investigated in human subjects. Fifteen participants aged 21–32 underwent an oral glucose tolerance test with five treatments: 1) 50-gram glucose solution (reference); 2). 50-gram glucose solution, followed by 12 mg of vegi-capsulated maltodextrin; 3) 50-gram glucose solution, followed by 120 mg of vegi-capsulated maltodextrin-encapsulated peanut skin extract; 4). 50-gram glucose solution, followed by 28 grams of unfortified coated peanuts; 5) 50-gram glucose solution, followed by 28 grams of chili lime coated peanuts fortified with encapsulated peanut skin extract. Glucose levels were measured using a continuous monitor. Peanut skin extract was found to attenuate the decrease in cell viability in high glucose treated HepG2 cells, showing a protective effect against hyperglycemia induced cell death. No difference in the glycemic response area under the curve between any treatments using the tolerance test, but the treatment of the peanut skin extract with the glucose reference resulted in a significantly lower peak blood glucose response at 45 minutes, indicating that it was effective at reducing the glycemic response. The present study shows that the phenolic extract of peanut skins has an antidiabetic effect, further confirming their value as a functional food ingredient.

Matrine Mediates Inflammatory Response via Gut Microbiota in TNBS-Induced Murine Colitis

This study mainly investigated the effect of matrine on TNBS-induced intestinal inflammation in mice. TNBS treatment caused colonic injury and gut inflammation. Matrine (1, 5, and 10 mg/kg) treatment alleviated colonic injury and gut inflammation via reducing bleeding and diarrhea and downregulating cytokines expression (IL-1β and TNF-α). Meanwhile, serum immunoglobulin G (IgG) was markedly reduced in TNBS treated mice, while 5 and 10 mg/kg matrine alleviated IgG reduction. Fecal microbiota was tested using 16S sequencing and the results showed that TNBS caused gut microbiota dysbiosis, while matrine treatment markedly improved gut microbiota communities (i.e., Bacilli and Mollicutes). Functional analysis showed that cell motility, nucleotide metabolism, and replication and repair were markedly altered in the TNBS group, while matrine treatment significantly affected cell growth and death, membrane transport, nucleotide metabolism, and replication and repair. In conclusion, matrine may serve as a protective mechanism in TNBS-induced colonic inflammation and the beneficial effect may be associated with gut microbiota.

A review of the molecular mechanisms of hyperglycemia-induced free radical generation leading to oxidative stress

The prevalence of diabetes is growing worldwide with an increasing morbidity and mortality associated with the development of diabetes complications. Free radical production is a normal biological process that is strictly controlled and has been shown to be important in normal cellular homeostasis, and in the bodies response to pathogens. However, there are several mechanisms leading to excessive free radical production that overcome the normal protective quenching mechanisms. Studies have shown that many of the diabetes complications result from excessive free radical generation and oxidative stress, and it has been shown that chronic hyperglycemia is a potent inducer for free radical production, generated through several pathways and triggering multiple molecular mechanisms. An understanding of these processes may help us to improving our preventive or therapeutic strategies. In this review, the major molecular pathways involved in free radical generation induced by hyperglycemia are described.

Molecular aspects of pancreatic β-cell dysfunction: Oxidative stress, microRNA, and long noncoding RNA

Metabolic syndrome is known as a frequent precursor of type 2 diabetes mellitus (T2D). This disease could affect 8% of the people worldwide. Given that pancreatic β-cell dysfunction and loss have central roles in the initiation and progression of the disease, the understanding of cellular and molecular pathways associated with pancreatic β-cell dysfunction can provide more information about the underlying pathways involved in T2D. Multiple lines evidence indicated that oxidative stress, microRNA, and long noncoding RNA play significant roles in various steps of diseases. Oxidative stress is one of the important factors involved in T2D pathogenesis. This could affect the function and survival of the β cell via activation or inhibition of several processes and targets, such as receptor-signal transduction, enzyme activity, gene expression, ion channel transport, and apoptosis. Besides oxidative stress, microRNAs and noncoding RNAs have emerged as epigenetic regulators that could affect pancreatic β-cell dysfunction. These molecules exert their effects via targeting a variety of cellular and molecular pathways involved in T2D pathogenesis. Here, we summarized the molecular aspects of pancreatic β-cell dysfunction. Moreover, we highlighted the roles of oxidative stress, microRNAs, and noncoding RNAs in pancreatic β-cell dysfunction.

Ellagic acid ameliorates oxidative stress and insulin resistance in high glucose-treated HepG2 cells via miR-223/keap1-Nrf2 pathway

As a promising new target, miR-233 may regulate oxidative stress by targeting keap1-Nrf2 system to affect the pathological process of liver injury in T2DM. Ellagic acid (EA) is versatile for protecting oxidative stress damage and metabolic disorders. In the present study, we investigated the effect of EA on oxidative stress and insulin resistance in high glucose-induced T2DM HepG2 cells and examined the role of miR-223/keap1-Nrf2 pathway in system. HepG2 cells were incubated in 30 mM of glucose, with or without EA (15 and 30 μM) or metformin (Met, 150 μM) for 12 h. Glucose consumption, phosphorylation of IRS1, Akt and ERK under insulin stimulation, ROS and O₂^- production, MDA level, SOD activity and miR-223 expression, as well as protein levels of keap1, Nrf2, HO-1, SOD1 and SOD2 were analyzed. Furthermore, dual luciferase reporter assay, miR-223 mimic and inhibitor were implemented in cellular studies to explore the possible mechanism. EA upregulated glucose consumption, IRS1, Akt and ERK phosphorylation under insulin stimulation, reduced ROS and O₂^- production and MDA level, and increased SOD activity in high glucose-exposed HepG2 cells. In addition, EA elevated miR-223 expression level, downregulated mRNA and protein levels of keap1, and upregulated Nrf2, HO-1, SOD1 and SOD2 protein levels in this cell model. What's more, dual luciferase reporter assay, miR-223 mimic and inhibitor transfection confirmed that EA activated keap1-Nrf2 system via elevating miR-223. The miR-223, a negative regulator of keap1, represents an attractive therapeutic target in hepatic injury in T2DM. EA ameliorates oxidative stress and insulin resistance via miR-223-mediated keap1-Nrf2 activation in high glucose-induced T2DM HepG2 cells.

Matrine induces apoptosis via targeting CCR7 and enhances the effect of anticancer drugs in non-small cell lung cancer in vitro

This study mainly investigated the effects of matrine on cell apoptosis and the effects of anticancer drugs in non-small cell lung cancer (NSCLC) cell lines (A549 and LK2 cells). The results showed that matrine (≥10 μM) caused a significant inhibition on cell viability and 10 and 100 μM matrine induced cell apoptosis via influencing p53, bax, casp3, and bcl-2 expressions in A549 cells. In addition, matrine significantly down-regulated C-C chemokine receptor type 7 (CCR7) expression, and blocking the down-regulation of CCR7 by exogenous chemokine ligand 21 (CCL21) treatment alleviated matrine-caused effects of apoptosis genes in A549 cells. The results were further validated in LK2 cells that matrine regulated apoptosis gene expressions, which were reversed by CCL21 treatment. Furthermore, matrine enhances the effects of cisplatin, 5-fluorouracil, and paclitaxel in A549 cells, and the anticancer effects exhibit a dosage-dependent manner. In summary, matrine induced cell apoptosis and enhanced the effects of anticancer drugs in NSCLC cells; the mechanism might be associated with the CCR7 signal.

Breviscapine ameliorates CCl4‑induced liver injury in mice through inhibiting inflammatory apoptotic response and ROS generation

Acute liver injury is characterized by fibrosis, inflammation and apoptosis, leading to liver failure, cirrhosis or cancer and affecting the clinical outcome in the long term. However, no effective therapeutic strategy is currently available. Breviscapine, a mixture of flavonoid glycosides, has been reported to have multiple biological functions. The present study aimed to investigate the effects of breviscapine on acute liver injury induced by CCl4 in mice. C57BL/6 mice were subjected to intraperitoneal injection with CCl4 for 8 weeks with or without breviscapine (15 or 30 mg/kg). Mice treated with CCl4 developed acute liver injury, as evidenced by histological analysis, Masson trichrome and Sirius Red staining, accompanied with elevated levels of alanine aminotransferase and aspartate aminotransferase. Furthermore, increases in pro‑inflammatory cytokines, chemokines and apoptotic factors, including caspase‑3 and poly(ADP ribose) polymerase‑2 (PARP‑2), were observed. Breviscapine treatment significantly and dose‑dependently reduced collagen deposition and the fibrotic area. Inflammatory cytokines were downregulated by breviscapine through inactivating Toll‑like receptor 4/nuclear factor-κB signaling pathways. In addition, co‑administration of breviscapine with CCl4 decreased the apoptotic response by enhancing B‑cell lymphoma-2 (Bcl‑2) levels, while reducing Bcl‑2‑associated X protein, apoptotic protease activating factor 1, caspase‑3 and PARP activity. Furthermore, CCl4‑induced oxidative stress was blocked by breviscapine through improving anti‑oxidants and impeding mitogen‑activated protein kinase pathways. The present study highlighted that breviscapine exhibited liver‑protective effects against acute hepatic injury induced by CCl4 via suppressing inflammation and apoptosis.

Protective effects of (-)-epicatechin and the colonic metabolite 3,4-dihydroxyphenylacetic acid against glucotoxicity-induced insulin signalling blockade and altered glucose uptake and production in renal tubular NRK-52E cells

Glucotoxicity (high levels of glucose) is a major cause in the pathogenesis of diabetes. Evidences indicate that (-)-epicatechin (EC) and colonic metabolites derived from flavonoid intake could possess antidiabetic effects, but the mechanisms for their preventive activities related to glucose homeostasis and insulin signalling in the kidney remain largely unknown. This work is aimed to investigate the effect of EC and main colonic phenolic acids derived from flavonoid intake, i.e. 2,3-dihydroxybenzoic-acid, 3,4-dihydroxyphenylacetic-acid (DHPAA) and 3-hydroxyphenylpropionic-acid, on insulin signalling, and glucose production and uptake in renal tubular proximal NRK-52E cells treated with high glucose. Pre-treatment with EC or DHPAA prevented the decreased tyrosine-phosphorylated and total levels of IR caused by high glucose. EC and DHPAA pre-treatment also avoided the inactivation of the PI3K/AKT pathway and AMPK, and the elevation of PEPCK levels induced by high glucose. Additionally, EC and DHPAA pre-treatment alleviated the altered glucose uptake and production caused by high glucose, although this protective effect was abrogated when AKT and AMPK were inhibited. These results suggest EC and DHPAA prevent or delay a potential dysfunction of NRK-52E cells treated with high glucose through the attenuation of the insulin signalling blockade and the modulation of glucose homeostasis via AKT and AMPK.

Broccoli Sprout Extract Alleviates Alcohol-Induced Oxidative Stress and Endoplasmic Reticulum Stress in C57BL/6 Mice

The potential efficacy of sulforaphane in protecting alcohol-induced hepatic injury in vivo and its underlying mechanism were investigated. Male C57BL/6 mice were orally administrated with broccoli sprout extract (BSE) containing sulforaphane [7.6, 25.2, and 50.4 mg/kg of body weight (bw)] once a day for 14 days. At the 13th day, mice were challenged with alcohol (5 g/kg of bw) every 12 h for 3 times, which increased malondialdehyde (MDA) levels (4.44 ± 1.24 nmol/mg of protein, p < 0.01) in the liver. Our results showed that low-, medium-, and high-dose BSE markedly reversed the decrease of antioxidant capacity through enhancing glutathione (GSH) (2.07 ± 0.31 mg/g of protein, p < 0.05; 2.31 ± 0.32 mg/g of protein, p < 0.01; and 2.46 ± 0.21 mg/g of protein, p < 0.01), superoxide dismutase (SOD) (483.20 ± 62.76 units/mg of protein; 500.81 ± 49.82 units/mg of protein, p < 0.05; and 605.00 ± < 64.32 units/mg of protein, p < 0.01), glutathione peroxidase (GSH-Px) (318 ± 60.74 units/mg of protein; 400.67 ± 72.47 units/mg of protein, p < 0.01; and 394.72 ± 62.97 units/mg of protein, p < 0.01), and glutathione S-transferase (GST) (31.84 ± 6.34 units/mg of protein, p < 0.05; 30.34 ± 6.40 units/mg of protein, p < 0.05; and 38.08 ± 7.05 units/mg of protein, p < 0.01) in the liver. The protective actions are also associated activation of phase 2 enzymes via nuclear erythoriod-2-related factor 2 (Nrf2). The endoplasmic reticulum (ER)-stress-specific proteins, such as glucose-regulated protein 78 (GRP78), activating transcription factor 6, and protein kinase RNA (PKR)-like ER kinase (PERK), were also significantly attenuated by BSE. These results indicate that BSE protects the liver against alcohol challenge via upregulating antioxidant capacity and downregulating ER stress.

Protective effects of selenium-glutathione-enriched probiotics on CCl4-induced liver fibrosis

Hepatic fibrosis is a common pathological basis of liver cirrhosis and hepatocellular carcinomas. So, prevention and treatment of liver fibrosis is one of the crucial therapeutic goals in hepatology. Organic selenium, glutathione or probiotics supplementation could ameliorate hepatic fibrosis, respectively. The purpose of this study is to develop a novel selenium-glutathione-enriched probiotics (SGP) and to investigate its protective effect on CCl₄-induced liver fibrosis in rats. Yeast strains with the high-yield glutathione were isolated and identified by analysis of 26S ribosomal DNA sequences. The fermentation parameters of SGP were optimized through single-factor, Plackett-Burman (PB) design and response surface methodology (RSM). The final SGP contained 38.4 μg/g of organic selenium, 34.1 mg/g of intracellular glutathione, approximately 1×10¹⁰ CFU/g live Saccharomyces cerevisiae and 1×10¹² CFU/g live Lactobacillus acidophilus. SGP had better protective effects on liver fibrosis than selenium, glutathione or probiotics, respectively. The hepatic silent information regulator 1 (SIRT1) level was down-regulated and oxidative stress, endoplasmic reticulum (ER) stress, inflammation and phosphorylated MAPK was increased in CCl₄-treated rats. However, SGP can significantly reverse these changes caused by CCl₄. Our findings suggest that SGP was effective in attenuating liver fibrosis by the activation of SIRT1 signaling and attenuating hepatic oxidative stress, ER stress, inflammation and MAPK signaling.

Potential Mechanisms of Action of Dietary Phytochemicals for Cancer Prevention by Targeting Cellular Signaling Transduction Pathways

Cancer is a severe health problem that significantly undermines life span and quality. Dietary approach helps provide preventive, nontoxic, and economical strategies against cancer. Increased intake of fruits, vegetables, and whole grains are linked to reduced risk of cancer and other chronic diseases. The anticancer activities of plant-based foods are related to the actions of phytochemicals. One potential mechanism of action of anticancer phytochemicals is that they regulate cellular signal transduction pathways and hence affects cancer cell behaviors such as proliferation, apoptosis, and invasion. Recent publications have reported phytochemicals to have anticancer activities through targeting a wide variety of cell signaling pathways at different levels, such as transcriptional or post-transcriptional regulation, protein activation and intercellular messaging. In this review, we discuss major groups of phytochemicals and their regulation on cell signaling transduction against carcinogenesis via key participators, such as Nrf2, CYP450, MAPK, Akt, JAK/STAT, Wnt/β-catenin, p53, NF-κB, and cancer-related miRNAs.

EGCG evokes Nrf2 nuclear translocation and dampens PTP1B expression to ameliorate metabolic misalignment under insulin resistance condition

As a major nutraceutical component of green tea (-)-epigallocatechin-3-gallate (EGCG) has attracted interest from scientists due to its well-documented antioxidant and antiobesity bioactivities. In the current study, we aimed to investigate the protective effect of EGCG on metabolic misalignment and in balancing the redox status in mice liver and HepG2 cells under insulin resistance condition. Our results indicated that EGCG accelerates the glucose uptake and evokes IRS-1/Akt/GLUT2 signaling pathway via dampening the expression of protein tyrosine phosphatase 1B (PTP1B). Consistently, ectopic expression of PTP1B by Ad-PTP1B substantially impaired EGCG-elicited IRS-1/Akt/GLUT2 signaling pathway. Moreover, EGCG co-treatment stimulated nuclear translocation of Nrf2 by provoking P13K/AKT signaling pathway and thus modulated the downstream expressions of antioxidant enzymes such as HO-1 and NQO-1 in HepG2 cells. Furthermore, knockdown Nrf2 by small interfering RNA (siRNA) notably enhanced the expression of PTP1B and blunt EGCG-stimulated glucose uptake. Consistent with these results, in vivo study revealed that EGCG supplement significantly ameliorated high-fat and high-fructose diet (HFFD)-triggered insulin resistance and oxidative stress by up-regulating the IRS-1/AKT and Keap1/Nrf2 transcriptional pathways. Administration of an appropriate chemopreventive agent, such as EGCG, could potentially serve as an additional therapeutic intervention in the arsenal against obesity.

The Potential and Action Mechanism of Polyphenols in the Treatment of Liver Diseases

Liver disease, involving a wide range of liver pathologies from fatty liver, hepatitis, and fibrosis to cirrhosis and hepatocellular carcinoma, is a serious health problem worldwide. In recent years, many natural foods and herbs with abundant phytochemicals have been proposed as health supplementation for patients with hepatic disorders. As an important category of phytochemicals, natural polyphenols have attracted increasing attention as potential agents for the prevention and treatment of liver diseases. The striking capacities in remitting oxidative stress, lipid metabolism, insulin resistance, and inflammation put polyphenols in the spotlight for the therapies of liver diseases. It has been reported that many polyphenols from a wide range of foods and herbs exert therapeutic effects on liver injuries via complicated mechanisms. Therefore, it is necessary to have a systematical review to sort out current researches to help better understand the potentials of polyphenols in liver diseases. In this review, we aim to summarize and update the existing evidence of natural polyphenols in the treatment of various liver diseases by in vitro, in vivo, and clinical studies, while special attention is paid to the action mechanisms.

(-)-Epicatechin and the Colonic 2,3-Dihydroxybenzoic Acid Metabolite Regulate Glucose Uptake, Glucose Production, and Improve Insulin Signaling in Renal NRK-52E Cells

SCOPE

(-)-Epicatechin (EC) and main colonic phenolic acids derived from flavonoid intake, such as 2,3-dihydroxybenzoic acid (DHBA), 3,4-dihydroxyphenylacetic acid (DHPAA), 3-hydroxyphenylpropionic acid (HPPA), and vanillic acid (VA), have been suggested to exert beneficial effects in diabetes, although the mechanism for their actions remains unknown. In this study, the modulation of glucose homeostasis and insulin signaling by the mentioned compounds on renal proximal tubular NRK-52E cells is investigated.

METHODS AND RESULTS

Levels of the glucose transporters SGLT-2 and GLUT-2, as well as glucose uptake, glucose production, and key proteins of the insulin pathways, namely insulin receptor (IR), insulin receptor substrate-1 (IRS-1), and PI3K/AKT pathway are analyzed. EC (5-20 μm) and DHBA (20 μm) reduced both renal glucose uptake and production. Interestingly, EC and DHBA did not modify the levels of SGLT-2 and GLUT-2, and modulated the expression of phosphoenolpyruvate carboxykinase via AKT leading to a diminished glucose production. EC and DHBA also enhanced the tyrosine phosphorylation and total IR and IRS-1 levels, and activated the PI3K/AKT pathway in NRK-52E cells.

CONCLUSION

EC and DHBA regulate the renal glucose homeostasis by modulating both glucose uptake and production, and strengthen the insulin signaling by activating key proteins of that pathway in NRK-52E cells.