Antioxidant and anti-inflammatory activities of lycopene against 5-fluorouracil-induced cytotoxicity in Caco2 cells.

5-fluorouracil (5FU) is widely used to treat colorectal cancer (CC) and its main mechanisms of anticancer action are through generation of ROS which often result in inflammation. Here, we test the effect of Lycopene against 5FU in Caco2 cell line. Caco2 cells were exposed to 3 µg/ml of 5FU alone or with 60, 90, 120 µg/ml of lycopene. This was followed by assessment of cytotoxicity, oxidative stress, and gene expression of inflammatory genes. Our findings showed that Lycopene and 5FU co-exposure induced dose-dependent cytotoxic effect without compromising the membrane integrity based on the LDH assay. Lycopene also significantly enhanced 5FU-induced SOD activity and GSH level compared to control for all mixture concentrations (p < 0.01). Lycopene alone and combination with 5FU-induced expression of IL-1ß, TNF-α, and IL-6. Furthermore, IFN-γ expression was significantly enhanced by only mixture of lycopene (90 µg/ml) and 5FU (p < 0.05). In conclusion, Lycopene supplementation with 5FU therapy resulted in improvement in antioxidant parameters such as catalase and GSH levels giving the cell capacity to cope with 5FU-mediated oxidative stress. Lycopene also enhanced IFN-γ expression in the presence of 5FU, which may activate antitumor effects further enhancing the cancer killing effect of 5FU.

Preclinical study for the ameliorating effect of l-ascorbic acid for the oxidative stress of chronic administration of organic nitrates on myocardial tissue in high sucrose/fat rat model.

Background: The therapeutic activity of Glyceryl trinitrate (GTN) is mainly regulated by liberating nitric oxide (NO) and reactive nitrogen species (RNS). During this biotransformation, oxidative stress and lipid peroxidation inside the red blood cells (RBCs) occur. Hemoglobin tightly binds to NO forming methemoglobin altering the erythrocytic antioxidant defense system. Aim: The principal objective of our research is to show the ameliorating effect of l-ascorbic acid for the deleterious effects of chronic administration of nitrovasodilator drugs used in cardiovascular diseases such as oxidative stresses and tolerance. Method: We studied some biochemical parameters for the oxidative stress using groups of high sucrose/fat (HSF) diet Wistar male rats chronically orally administered different concentrations of Isosorbide-5-mononitrate (ISMN) 0.3 mg/kg, 0.6 mg/kg and 1.2 mg/kg. Afterwards, we evaluated the role of l-ascorbic acid against these biochemical changes in cardiac tissues. Results: Chronic treatment with organic nitrates caused elevated serum levels of lipid peroxidation, hemoglobin derivatives as methemoglobin and carboxyhemoglobin, rate of hemoglobin autoxidation, the cellular levels of the pro-inflammatory cytokines marker (NF-κB) and apoptosis markers (caspase-3) in the myocardium muscles in a dose-dependent manner. Meanwhile, such exposure caused a decline in the enzymatic effect of SOD, GSH and CAT accompanied by a decrease in the level of mitochondrial oxidative stress marker (nrf2) in the myocardium muscles and a decrease in the serum iron and total iron-binding capacity (TIBC) in a dose-dependent manner. Concomitant treatment with l-ascorbic acid significantly diminished these changes for all examined parameters. Conclusion: Chronic administration of organic nitrates leads to the alteration of the level of oxidative stress factors in the myocardium tissue due to the generation of reactive oxygen species. Using l-ascorbic acid can effectively ameliorate such intoxication to overcome nitrate tolerance.

Empagliflozin attenuates neurodegeneration through antioxidant, anti-inflammatory, and modulation of α-synuclein and Parkin levels in rotenone-induced Parkinson's disease in rats.

Sodium-glucose co-transporter 2 (SGLT 2) inhibitors are a relatively new antidiabetic drug with antioxidant and anti-inflammatory properties. Therefore, this study aimed to investigate whether SGLT 2 inhibitors have a neuroprotective effect in PD. Twenty-four Wistar rats were randomized into four groups. The first one (control group) received dimethyl sulfoxide (DMSO) as a vehicle (0.2 mL/48 hr, S.C). The second group (positive control) received rotenone (ROT) (2.5 mg/kg/48 hr, S.C) for 20 successive days, whereas the third and fourth groups received empagliflozin (EMP) (1 and 2 mg/kg/day, orally), respectively. The two groups received rotenone (2.5 mg/kg/48 hr S.C) concomitantly with EMP for another 20 days on the fifth day. By the end of the experimental period, behavioral examinations were done. Subsequently, rats were sacrificed, blood samples and brain tissues were collected for analysis. ROT significantly elevated oxidative stress and proinflammatory markers as well as α-synuclein. However, dopamine (DP), antioxidants, tyrosine hydroxylase (TH), and Parkin were significantly decreased. Groups of (EMP + ROT) significantly maintained oxidative stress and inflammatory markers elevation, maintained α-synuclein and Parkin levels, and elevated TH activity and dopamine level. In both low and high doses, EMP produced a neuroprotective effect against the PD rat model, with the high dose inducing a more significant effect.

Cardioprotective effects of sinomenine in myocardial ischemia/reperfusion injury in a rat model.

Background: Ischemia reperfusion (I/R) play an imperative role in the expansion of cardiovascular disease. Sinomenine (SM) has been exhibited to possess antioxidant, anticancer, anti-inflammatory, antiviral and anticarcinogenic properties. The aim of the study was scrutinized the cardioprotective effect of SM against I/R injury in rat. Methods: Rat were randomly divided into normal control (NC), I/R control and I/R + SM (5, 10 and 20 mg/kg), respectively. Ventricular arrhythmias, body weight and heart weight were estimated. Antioxidant, inflammatory cytokines, inflammatory mediators and plasmin system indicator were accessed. Results: Pre-treated SM group rats exhibited the reduction in the duration and incidence of ventricular fibrillation, ventricular ectopic beat (VEB) and ventricular tachycardia along with suppression of arrhythmia score during the ischemia (30 and 120 min). SM treated rats significantly (P < 0.001) altered the level of antioxidant parameters. SM treatment significantly (P < 0.001) repressed the level of creatine kinase MB (CK-MB), creatine kinase (CK) and troponin I (Tnl). SM treated rats significantly (P < 0.001) repressed the tissue factor (TF), thromboxane B2 (TXB2), plasminogen activator inhibitor 1 (PAI-1) and plasma fibrinogen (Fbg) and inflammatory cytokines and inflammatory mediators. Conclusion: Our result clearly indicated that SM plays anti-arrhythmia effect in I/R injury in the rats via alteration of oxidative stress and inflammatory reaction.

Cinnamomum zeylanicum Blume (Ceylon cinnamon) bark extract attenuates doxorubicin induced cardiotoxicity in Wistar rats.

Anti-tumour efficacy of doxorubicin is hindered by the cumulative dose-dependent cardiotoxicity induced by reactive oxygen species during its metabolism. As Cinnamomum zeylanicum has proven antioxidant potential, objective of this study was to investigate the cardioprotective activity of Cinnamomum bark extract against doxorubicin induced cardiotoxicity in Wistar rats. Physicochemical and phytochemical analysis was carried out and dose response effect and the cardioprotective activity of Cinnamomum were determined in vivo. 180 mg/kg dexrazoxane was used as the positive control. Plant extracts were free of heavy metals and toxic phytoconstituents. In vivo study carried out in Wistar rats revealed a significant increase (p < 0.05) in cardiac troponin I, NT-pro brain natriuretic peptide, AST and LDH concentrations in the doxorubicin control group (18 mg/kg) compared to the normal control. Rats pre-treated with the optimum dosage of Cinnmamomum (2.0 g/kg) showed a significant reduction (p < 0.05) in all above parameters compared to the doxorubicin control. A significant reduction was observed in the total antioxidant capacity, reduced glutathione, glutathione peroxidase, glutathione reductase, superoxide dismutase and catalase activity while the lipid peroxidation and myeloperoxidase activity were significantly increased in the doxorubicin control group compared to the normal control (p < 0.05). Pre-treatment with Cinnamomum bark showed a significant decrease in lipid peroxidation, myeloperoxidase activity and significant increase in rest of the parameters compared to the doxorubicin control (p < 0.05). Histopathological analysis revealed a preserved appearance of the myocardium and lesser degree of cellular changes of necrosis in rats pre-treated with Cinnamomum extract. In conclusion, Cinnamomum bark extract has the potential to significantly reduce doxorubicin induced oxidative stress and inflammation in Wistar rats.

Defining the role of CFTR channel blocker and ClC-2 activator in DNBS induced gastrointestinal inflammation.

In the present study, we have investigated and/or compared the role of glibenclamide, G as cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor, and lubiprostone, L as chloride channel-2 (ClC-2) activator in the 2,4-dinitrobenzene sulfonic acid (DNBS)-induced gastrointestinal inflammation. GI inflammation was induced by intrarectal administration of DNBS. Rats were randomly allocated in 5 groups as sham control, distilled water + DNBS, sulfasalazine (S) + DNBS, G + DNBS, and L + DNBS. All the groups were pre-treated successively for five days before the induction of colitis. One day before and the first four days after DNBS administration various parameters were studied. Later, blood chemistry, colon's gross structure, histology, and the antioxidant load was examined. Pre-treatment with G significantly protected the change induced by DNBS concerning the change in body weight, food intake, diarrhea, occult blood in the feces, wet weight of the colon, and spleen. G because of its anti-inflammatory property down-regulated the neutrophil and WBC count and up-regulated the lymphocyte number. Moreover, G efficiently ameliorates the oxidative stress in the colon and declines the level of myeloperoxidase and malondialdehyde and up-regulated the level of superoxide dismutase and glutathione. Lubiprostone has not shown any promising effects, in fact, it causes an increase in diarrheal frequency. Our findings from this study represent that G has good potential to ameliorate GI inflammation induced by DNBS by its multiple actions including CFTR blockage and reducing the release of inflammatory markers from the MCs, anti-inflammatory and free radical scavenging property.

The potential role of sesquiterpene lactones isolated from medicinal plants in the treatment of the metabolic syndrome - A review.

Metabolic syndrome comprises a cluster of metabolic disorders related to the development of cardiovascular disease and type 2 diabetes mellitus. In latter years, plant secondary metabolites have become of special interest because of their potential role in preventing and managing metabolic syndrome. Sesquiterpene lactones constitute a large and diverse group of biologically active compounds widely distributed in several medicinal plants used for the treatment of metabolic disorders. The structural diversity and the broad spectrum of biological activities of these compounds drew significant interests in the pharmacological applications. This review describes selected sesquiterpene lactones that have been experimentally validated for their biological activities related to risk factors of metabolic syndrome, together with their mechanisms of action. The potential beneficial effects of sesquiterpene lactones discussed in this review demonstrate that these substances represent remarkable compounds with a diversity of molecular structure and high biological activity, providing new insights into the possible role in metabolic syndrome management.

Effect of pyrroloquinoline quinone disodium in female rats during gestating and lactating on reproductive performance and the intestinal barrier functions in the progeny.

The objective of this study was to investigate the effects of dietary pyrroloquinoline quinone disodium (PQQ·Na2) supplementation on the reproductive performance and intestinal barrier functions of gestating and lactating female Sprague-Dawley (SD) rats and their offspring. Dietary supplementation with PQQ·Na2 increased the number of implanted embryos per litter during gestation and lactation at GD 20 and increased the number of viable fetuses per litter, and the weight of uterine horns with fetuses increased at 1 d of newborn. The mRNA expression levels of catalase (CAT), glutathione peroxidase (GPx2), superoxide dismutase (SOD1), solute carrier family 2 member 1 (Slc2a1) and solute carrier family 2 member 3 (Slc2a3) in the placenta were increased with dietary PQQ·Na2 supplementation. Dietary supplementation with PQQ·Na2 in gestating and lactating rats increased the CAT, SOD and GPx activities of the jejunal mucosa of weaned rats on PD 21. Dietary supplementation with PQQ·Na2 in female rats affected the expression of tight junction proteins (claudin, zonula occludens-1 (ZO-1) and occludin) in the jejunal mucosa of their offspring by increasing the expression of ZO-1 mRNA in the expression of ZO-1 and claudin mRNA in the jejunal mucosa of weaned rats on PD 21. In conclusion, dietary supplementation with PQQ·Na2 in gestating and lactating female rats had positive effects on their reproductive performance and on the intestinal barrier of weaned rats.

Acute dietary zinc deficiency in rats exacerbates myocardial ischaemia-reperfusion injury through depletion of glutathione.

Zn plays an important role in maintaining the anti-oxidant status within the heart and helps to counter the acute redox stress that occurs during myocardial ischaemia and reperfusion. Individuals with low Zn levels are at greater risk of developing an acute myocardial infarction; however, the impact of this on the extent of myocardial injury is unknown. The present study aimed to compare the effects of dietary Zn depletion with in vitro removal of Zn (N,N,N',N'-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN)) on the outcome of acute myocardial infarction and vascular function. Male Sprague-Dawley rats were fed either a Zn-adequate (35 mg Zn/kg diet) or Zn-deficient (<1 mg Zn/kg diet) diet for 2 weeks before heart isolation. Perfused hearts were subjected to a 30 min ischaemia/2 h reperfusion (I/R) protocol, during which time ventricular arrhythmias were recorded and after which infarct size was measured, along with markers of anti-oxidant status. In separate experiments, hearts were challenged with the Zn chelator TPEN (10 µm) before ischaemia onset. Both dietary and TPEN-induced Zn depletion significantly extended infarct size; dietary Zn depletion was associated with reduced total cardiac glutathione (GSH) levels, while TPEN decreased cardiac superoxide dismutase 1 levels. TPEN, but not dietary Zn depletion, also suppressed ventricular arrhythmias and depressed vascular responses to nitric oxide. These findings demonstrate that both modes of Zn depletion worsen the outcome from I/R but through different mechanisms. Dietary Zn deficiency, resulting in reduced cardiac GSH, is the most appropriate model for determining the role of endogenous Zn in I/R injury.

The controversial role of vitamin D as an antioxidant: results from randomised controlled trials.

Increased oxidative stress has been implicated as a potential causal factor in the development of several diseases. In the last decade, an extensive literature has been produced on vitamin D, not limited to its well-known function like a steroid hormone on skeletal tissue, but for its potential pleiotropic role in human health. Several researchers have suggested relationships between vitamin D intake and health outcomes such as cancer prevention and increased immunity, or possible role in preventing diabetes, and in inflammation. Little is known about its antioxidant effect. The aim of the present review was to explore major evidence regarding the potential scavenger capacity of vitamin D in high-evidence human studies. Studies considered by the present review suggest that the potential role of vitamin D as an antioxidant could not be confirmed. Current literature showed controversial effects about the ability of cholecalciferol to prevent or ameliorate oxidative stress biomarkers, and there is need of further and high-quality studies testing the antioxidant effect of vitamin D supplementation.

Maternal high-salt diet alters redox state and mitochondrial function in newborn rat offspring's brain.

Excessive salt intake is a common feature of Western dietary patterns, and has been associated with important metabolic changes including cerebral redox state imbalance. Considering that little is known about the effect on progeny of excessive salt intake during pregnancy, the present study investigated the effect of a high-salt diet during pregnancy and lactation on mitochondrial parameters and the redox state of the brains of resulting offspring. Adult female Wistar rats were divided into two dietary groups (n 20 rats/group): control standard chow (0·675 % NaCl) or high-salt chow (7·2 % NaCl), received throughout pregnancy and for 7 d after delivery. On postnatal day 7, the pups were euthanised and their cerebellum, hypothalamus, hippocampus, prefrontal and parietal cortices were dissected. Maternal high-salt diet reduced cerebellar mitochondrial mass and membrane potential, promoted an increase in reactive oxygen species allied to superoxide dismutase activation and decreased offspring cerebellar nitric oxide levels. A significant increase in hypothalamic nitric oxide levels and mitochondrial superoxide in the hippocampus and prefrontal cortex was observed in the maternal high-salt group. Antioxidant enzymes were differentially modulated by oxidant increases in each brain area studied. Taken together, our results suggest that a maternal high-salt diet during pregnancy and lactation programmes the brain metabolism of offspring, favouring impaired mitochondrial function and promoting an oxidative environment; this highlights the adverse effect of high-salt intake in the health state of the offspring.

Involvement of NLRP3 inflammasome in the impacts of sodium and potassium on insulin resistance in normotensive Asians.

Salt, promoting oxidative stress, contributes to insulin resistance, whereas K, inhibiting oxidative stress, improves insulin sensitivity. Oxidative stress activation of NLRP3 inflammasome is a central player in the induction of insulin resistance. Therefore, we hypothesised that NLRP3 inflammasome may mediate the effects of salt and K on insulin resistance. In all, fifty normotensive subjects were recruited from a rural community of Northern China. The protocol included a low-salt diet for 7 d, then a high-salt diet for 7 d and a high-salt diet with K supplementation for another 7 d. In addition, THP-1 cells were cultured in different levels of Na with and without K. The results showed that salt loading elevated fasting blood glucose, insulin and C-peptide levels, as well as insulin resistance, whereas K supplementation reversed them. Meanwhile, additional K reversed the active effects of high salt on NLRP3 inflammasome in both the subjects and THP-1 cells, and the change of insulin resistance index notably related with the alteration of plasma IL-1ß, the index of NLRP3 inflammasome activation, during intervention in the subjects. Additional K ameliorated oxidative stress induced by high salt in both the subjects and cultured THP-1 cells, and the change of oxidative stress related with the alteration of plasma IL-1ß during intervention in the subjects. In vitro, antioxidant N-acetyl-l-cysteine significantly prevented the active effects of high Na or oxidant Rosup on NLRP3 inflammasome, so did K. Our study indicates that oxidative stress modulation of NLRP3 inflammasome may be involved in the impacts of Na and K on insulin resistance.

Effect of liquid ubiquinol supplementation on glucose, lipids and antioxidant capacity in type 2 diabetes patients: a double-blind, randomised, placebo-controlled trial.

Ubiquinone is a lipid antioxidant, and a novel liquid ubiquinol (a hydro-soluble, reduced form of coenzyme Q10) supplement was recently developed. The purpose of this study was to examine the levels of glucose, lipids and antioxidant capacity of type 2 diabetes patients after liquid ubiquinol supplementation. This study was designed as a randomised, double-blind, placebo-controlled trial. In all, fifty participants were randomly assigned to a placebo (n 25) or liquid ubiquinol (100 mg/d, n 25) group, and the intervention lasted for 12 weeks. Plasma coenzyme Q10, glucose homoeostasis parameters, lipid profiles, oxidative stress and antioxidative enzyme activities were measured during the study. After 12 weeks of supplementation, glyco Hb (HbA1c) value was significantly decreased in the liquid ubiquinol group (P=0·03), and subjects in the liquid ubiquinol group had significantly lower anti-glycaemic medication effect scores (MES) compared with those in the placebo group (P=0·03). The catalase (P<0·01) and glutathione peroxidase (P=0·03) activities were increased significantly after supplementation. Plasma coenzyme Q10 was correlated with the insulin level (P=0·05), homoeostatic model assessment-insulin resistance (P=0·07), quantitative insulin sensitivity check index (P=0·03) and the anti-hyperglycaemic agents' MES (P=0·03) after supplementation. Lipid profiles did not change after supplementation; however, the subjects in the placebo group had a significantly lower level of HDL-cholesterol after 12 weeks of intervention. In conclusion, oral intake of 100 mg/d liquid ubiquinol might benefit type 2 diabetes patients by increasing antioxidant enzyme activity levels, reducing HbA1c levels and maintaining HDL-cholesterol levels.

Low-protein diet supplemented with ketoacids delays the progression of diabetic nephropathy by inhibiting oxidative stress in the KKAy mice model.

Diabetic nephropathy (DN) is a major cause of chronic kidney disease. We aimed to investigate the effect of the low-protein diets (LPD) supplemented with ketoacids (LPD+KA) in KKAy mice, an early type 2 DN model. KKAy mice were treated with normal protein diet (NPD), LPD or LPD+KA from 12 to 24 weeks of age. A period of 12-week treatment with LPD significantly reduced albuminuria as compared with that observed after NPD treatment. Treatment with LPD+KA further reduced albuminuria as compared with that observed with LPD treatment alone. Moreover, LPD treatment reduced mesangial expansion, thickness of glomerular basement membrane and the severity of the podocyte foot process effacement in KKAy mice; these effects were more pronounced in KKAy mice treated with LPD+KA. Both LPD and LPD+KA treatments slightly reduced total body weight, but had no significant effect on kidney weight and blood glucose concentrations when compared with NPD-treated KKAy mice. LPD treatment slightly attenuated oxidative stress in kidneys as compared with that observed in NPD-treated KKAy mice; however, LPD+KA treatment remarkably ameliorated oxidative stress in diabetic kidneys as shown by decreased malondialdehyde concentrations, protein carbonylation, nitrotyrosine expression and increased superoxide dismutase expression. Nutritional therapy using LPD+KA confers additional renal benefits as compared with those of LPD treatment alone in early type 2 DN through inhibition of oxidative stress.

Dietary curcumin supplementation attenuates inflammation, hepatic injury and oxidative damage in a rat model of intra-uterine growth retardation.

Rats with a normal birth weight (NBW) or intra-uterine growth retardation (IUGR) were fed basic diets (NBW and IUGR groups) or basic diets supplemented with curcumin (NC and IC groups) from 6 to 12 weeks. The body weight of IUGR rats was lower (P<0·05) than that of the controls. Rats with IUGR showed higher (P<0·05) concentrations of TNF-α, IL-1ß and IL-6; higher (P<0·05) activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in their serum; and increased (P<0·05) concentrations of malondialdehyde (MDA), protein carbonyl (PC) and 8-hydroxy-2'-deoxyguanosine (8-OHDG) in the liver compared with the NBW rats. The livers of IUGR rats exhibited a lower (P<0·05) superoxide dismutase activity and decreased (P<0·05) metabolic efficiency of the hepatic glutathione redox cycle compared with those of the NBW rats. In response to dietary curcumin supplementation, concentrations of inflammatory cytokines and activities of AST and ALT in the serum and MDA, PC and 8-OHDG in the liver were lower (P<0·05), and the hepatic glutathione redox cycle in the liver was improved (P<0·05) in the IC group than in the IUGR group. These results were associated with lower (P<0·05) phosphorylated levels of the NF-κB pathway and Janus kinase 2 (JAK2) and higher (P<0·05) mRNA expression of genes involved in the nuclear factor, erythroid 2-like 2 (Nfe2l2)/antioxidant response element (ARE) pathway in the liver of the IC rats than that of the IUGR rats. Maternal undernutrition decreased birth weight and led to inflammation, oxidative damage and injury in rats. Curcumin appeared to be beneficial in preventing IUGR-induced inflammation, oxidative damage and injury by activating the expression of the NF-κB, JAK/STAT and Nfe2l2/ARE pathways in the liver.

In vitro and in vivo antioxidant potential of milks, yoghurts, fermented milks and cheeses: a narrative review of evidence.

The antioxidant potential (AP) is an important nutritional property of foods, as increased oxidative stress is involved in most diet-related chronic diseases. In dairy products, the protein fraction contains antioxidant activity, especially casein. Other antioxidants include: antioxidant enzymes; lactoferrin; conjugated linoleic acid; coenzyme Q10; vitamins C, E, A and D3; equol; uric acid; carotenoids; and mineral activators of antioxidant enzymes. The AP of dairy products has been extensively studied in vitro, with few studies in animals and human subjects. Available in vivo studies greatly differ in their design and objectives. Overall, on a 100 g fresh weight-basis, AP of dairy products is close to that of grain-based foods and vegetable or fruit juices. Among dairy products, cheeses present the highest AP due to their higher protein content. AP of milk increases during digestion by up to 2·5 times because of released antioxidant peptides. AP of casein is linked to specific amino acids, whereas ß-lactoglobulin thiol groups play a major role in the AP of whey. Thermal treatments such as ultra-high temperature processing have no clear effect on the AP of milk. Raw fat-rich milks have higher AP than less fat-rich milk, because of lipophilic antioxidants. Probiotic yoghurts and fermented milks have higher AP than conventional yoghurt and milk because proteolysis by probiotics releases antioxidant peptides. Among the probiotics, Lactobacillus casei/acidophilus leads to the highest AP. The data are insufficient for cheese, but fermentation-based changes appear to make a positive impact on AP. In conclusion, AP might participate in the reported dairy product-protective effects against some chronic diseases.

Probiotics, prebiotics, synbiotics and insulin sensitivity.

Animal studies indicate that the composition of gut microbiota may be involved in the progression of insulin resistance to type 2 diabetes. Probiotics and/or prebiotics could be a promising approach to improve insulin sensitivity by favourably modifying the composition of the gut microbial community, reducing intestinal endotoxin concentrations and decreasing energy harvest. The aim of the present review was to investigate the effects of probiotics, prebiotics and synbiotics (a combination of probiotics and prebiotics) on insulin resistance in human clinical trials and to discuss the potential mechanisms whereby probiotics and prebiotics improve glucose metabolism. The anti-diabetic effects of probiotics include reducing pro-inflammatory cytokines via a NF-κB pathway, reduced intestinal permeability, and lowered oxidative stress. SCFA play a key role in glucose homeostasis through multiple potential mechanisms of action. Activation of G-protein-coupled receptors on L-cells by SCFA promotes the release of glucagon-like peptide-1 and peptide YY resulting in increased insulin and decreased glucagon secretion, and suppressed appetite. SCFA can decrease intestinal permeability and decrease circulating endotoxins, lowering inflammation and oxidative stress. SCFA may also have anti-lipolytic activities in adipocytes and improve insulin sensitivity via GLUT4 through the up-regulation of 5'-AMP-activated protein kinase signalling in muscle and liver tissues. Resistant starch and synbiotics appear to have favourable anti-diabetic effects. However, there are few human interventions. Further well-designed human clinical studies are required to develop recommendations for the prevention of type 2 diabetes with pro- and prebiotics.

Oligomeric forms of bacterial malate dehydrogenase: a study of the enzyme from the phototrophic non-sulfur bacterium Rhodovulum steppense A-20s.

Malate dehydrogenase (EC 1.1.1.37) was purified to homogeneity from the phototrophic purple non-sulfur bacterium Rhodovulum steppense A-20s. According to gel-chromatography and electrophoretic studies, malate dehydrogenase is present as a dimer, tetramer and octamer depending on cultivation conditions. In phototrophic aerobic conditions only the tetrameric form was present, in chemotrophic aerobic conditions all three forms were detected, while in the absence of oxygen the octameric form disappeared. The malate dehydrogenase oligomers are encoded by a single gene and composed of the same 35 kDa polypeptide but differ in pH and temperature optimum, in affinities to malate, oxaloacetate, NADH and NAD+ and in regulation by cations and citrate. By modulating the cultivation conditions, it has been established that the dimer participates in the glyoxylate cycle; the tetramer operates in the tricarboxylic acid cycle, and the octamer may be involved in the adaptation to oxidative stress.

Comparative analysis of effects of dietary arachidonic acid and EPA on growth, tissue fatty acid composition, antioxidant response and lipid metabolism in juvenile grass carp, Ctenopharyngodon idellus.

Four isonitrogenous and isoenergetic purified diets containing free arachidonic acid (ARA) or EPA (control group), 0·30 % ARA, 0·30 % EPA and 0·30 % ARA+EPA (equivalent) were designed to feed juvenile grass carp (10·21 (sd 0·10) g) for 10 weeks. Only the EPA group presented better growth performance compared with the control group (P<0·05). Dietary ARA and EPA were incorporated into polar lipids more than non-polar lipids in hepatopancreas but not intraperitoneal fat (IPF) tissue. Fish fed ARA and EPA showed an increase of serum superoxide dismutase and catalase activities, and decrease of glutathione peroxidase activity and malondialdehyde contents (P<0·05). The hepatopancreatic TAG levels decreased both in ARA and EPA groups (P<0·05), accompanied by the decrease of lipoprotein lipase (LPL) activity in the ARA group (P<0·05). Fatty acid synthase (FAS), diacylglycerol O-acyltransferase and apoE gene expression in the hepatopancreas decreased in fish fed ARA and EPA, but only the ARA group exhibited increased mRNA level of adipose TAG lipase (ATGL) (P<0·05). Decreased IPF index and adipocyte sizes were found in the ARA group (P<0·05). Meanwhile, the ARA group showed decreased expression levels of adipogenic genes CCAAT enhancer-binding protein α, LPL and FAS, and increased levels of the lipid catabolic genes PPAR α, ATGL, hormone-sensitive lipase and carnitine palmitoyltransferase 1 (CPT-1) in IPF, whereas the EPA group only increased PPAR α and CPT-1 mRNA expression and showed less levels than the ARA group. Overall, dietary EPA is beneficial to the growth performance, whereas ARA is more potent in inducing lipolysis and inhibiting adipogenesis, especially in IPF. Meanwhile, dietary ARA and EPA showed the similar preference in esterification and the improvement in antioxidant response.

Colonic and systemic effects of extruded whole-grain sorghum consumption in growing Wistar rats.

Colonic effects of extruded whole-grain sorghum diets were evaluated using a model of growing rats. In all, twenty-four male Wistar rats were fed control (C), extruded white sorghum (EWS) or red sorghum (ERS). Consumption of sorghum diets showed satiety properties, with reduction of caecal pH, and lower activity of ß-glucosidase and ß-glucuronidase enzymes. Decreased copper zinc superoxide dismutase and manganese superoxide dismutase and increased catalase and glutathione peroxidase levels were observed in colonic mucosa. The induction of antioxidant enzymes occurred through the activation of the nuclear factor erythroid 2-related factor 2 protein and its subsequent translocation into the nucleus. ERS was able to decrease the proliferation of proximal mucosa of colon, demonstrating a possible effect against colorectal tumourigenesis. EWS increased proliferation and also apoptosis, ensuring the re-establishment of homoeostasis of the colonic mucosa. No antioxidant systemic effect (serum or hepatic level) was observed. It is likely that despite the extrusion the low bioavailability of the phenolic compounds of sorghum diets caused them to exert mainly acute effects at the colon level. Extruded whole-grain sorghum is a good functional ingredient that might be promising in dietary prevention of intestinal diseases.