Intake of purple grape juice as a hepatoprotective agent in Wistar rats

Chemometrics-assisted excitation-emission matrix fluorescence spectroscopy for rapid identification of commercial reconstituted and sweetened grape juices

As a common fruit juice, grape juice is delicious and nutritious, making it very popular among consumers. However, some illegal manufacturers used shoddy products to lower costs and obtain high profits, which seriously threatens the health and interests of consumers. Hence, this paper proposed excitation-emission matrix (EEM) fluorescence spectroscopy combined with chemometric methods for the rapid identification and classification of commercial grape juices. Spectral characterization of different samples was achieved using the alternating trilinear decomposition (ATLD) algorithm, and chemically meaningful information was obtained and analyzed. Although both reconstituted and sweetened grape juices contain methyl anthranilate (MA) and 2'-aminoacetophenone (o-AAP), the content of MA in sweetened grape juice far exceeds that in reconstituted grape juice, and the MA in sweetened grape juice mainly comes from artificially added grape essence. Then two chemometric methods of hierarchical cluster analysis (HCA) and partial least squares discriminant analysis (PLS-DA) were used for the classification of reconstituted and sweetened grape juices. The results showed that the supervised classification model had a higher correct classification rate (CCR) than the unsupervised classification model, with PLS-DA obtaining 100% CCRs in both training and prediction sets. Therefore, the proposed strategy can be used as a powerful analytical method for the identification and classification of reconstituted and sweetened grape juices and provides a reliable scientific means for ensuring the authenticity and safety of the juice market.

The effect of black seed raisin on some cardiovascular risk factors, serum malondialdehyde, and total antioxidant capacity in hyperlipidemic patients: a randomized controlled trials

BACKGROUND

The lipid-lowering properties and antioxidants of the raisins may reduce the risk factors of cardiovascular diseases. This study aimed to investigate the effect of black seeded raisin consumption on blood pressure (BP), lipid profile, high-sensitivity C-reactive protein (hs-CRP), malondialdehyde (MDA), and serum total antioxidant capacity (TAC) in hyperlipidemic patients.

METHODS

Thirty-eight hyperlipidemic patients aged 41.05 ± 10.4 years were recruited to this two-armed, randomized, controlled intervention trial. Participants were instructed to consume 90 g per day black seed raisin in the intervention group, and control group received no intervention. BP, lipid profile, and plasma levels of TAC, MDA, hs-CRP, and FBS were determined at baseline and week 5.

RESULTS

After 5 weeks, the diastolic BP reduced significantly in raisin group compared with baseline (81.80 ± 10.22 vs 77.05 ± 11.03, P = 0.001) and TAC was significantly increased in raisin group compared with the control group (394 ± 116.93 vs 479 ± 122.31, P = 0.001). The serum level of MDA in the raisin group was significantly lower compared with the control group (1.35 ± 0.88 vs 1.39 ± 0.67, P = 0.039). No significant changes were found in lipid profile, SBP, hs-CRP, and FBS.

CONCLUSION

These results suggest that consumption of black raisin which is rich in polyphenolic compounds has beneficial effects on some cardiovascular risk factors especially blood pressure and serum antioxidant capacity in patients with hyperlipidemia.

TRIAL REGISTRATION

Trial registration number: IRCT2015091624049N1. This study was registered in the Iranian Registry of Clinical Trials (IRCT). URL of trial registry record: https://www.irct.ir/trial/20395.

Resveratrol and Quercetin Administration Improves Antioxidant DEFENSES and reduces Fatty Liver in Metabolic Syndrome Rats

Mixtures of resveratrol (RSV) + quercetin (QRC) have antioxidant properties that probably impact on fatty liver in metabolic syndrome (MS) individuals. Here, we study the effects of a mixture of RSV + QRC on oxidative stress (OS) and fatty liver in a rat model of MS. Weanling male Wistar rats were separated into four groups (n = 8): MS rats with 30% sucrose in drinking water plus RSV + QRC (50 and 0.95 mg/kg/day, respectively), MS rats without treatment, control rats (C), and C rats plus RSV + QRC. MS rats had increased systolic blood pressure, triglycerides, insulin levels, insulin resistance index homeostasis model (HOMA), adiponectin, and leptin. The RSV + QRC mixture compensated these variables to C values (p < 0.01) in MS rats. Lipid peroxidation and carbonylation were increased in MS. Total antioxidant capacity and glutathione (GSH) were decreased in MS and compensated in MS plus RVS + QRC rats. Catalase, superoxide dismutase isoforms, peroxidases, glutathione-S-transferase, glutathione reductase, and the expression of Nrf2 were decreased in MS and reversed in MS plus RVS + QRC rats (p < 0.01). In conclusion, the mixture of RSV + QRC has benefic effects on OS in fatty liver in the MS rats through the improvement of the antioxidant capacity and by the over-expression of the master factor Nrf2, which increases the antioxidant enzymes and GSH recycling.

Grape Juice Consumption with or without High Fat Diet during Pregnancy Reduced the Weight Gain and Improved Lipid Profile and Oxidative Stress Levels in Liver and Serum from Wistar Rats

The aim of this study was to evaluate the effects of high fat diet with or without grape juice during the pregnancy on gestational weight gain, biochemical parameters, and oxidative stress in plasma and liver from Wistar rats. Forty-nine rats were divided into four groups: control diet group (CD), high fat diet (HFD), grape juice and control diet (PGJCD), and grape juice and high fat diet (PGJHFD). During the treatment the weight gain of the rats was tracked. They had free access to their respective diets during 42 days of treatment. After offspring weaning, the mother rats were euthanized and blood and liver were collected. The high fat diet increased the total cholesterol and triglycerides serum levels as well as carbonyl levels in the liver, however this diet reduced the high-density lipoprotein (HDL) and urea levels in serum. Grape juice consumption reduced gestational body weight gain. In liver, the juice consumption increased sulfhydryl levels and reduced the superoxide dismutase (SOD) activity and TBARS level, in serum the consumption reduced aspartate aminotransferase (AST) and TBARS. We can conclude that the consumption of a diet rich in fat can promotes harmful effects on health during pregnancy, however the consumption of grape juice seems to be an important alternative to prevent oxidative damages and to promote the improvement of health.

Protective effects of red grape (Vitis vinifera) juice through restoration of antioxidant defense, endocrine swing and Hsf1, Hsp72 levels in heat stress induced testicular dysregulation of Wister rat

Ability of red grape juice (RGJ), a known antioxidant, on testis of adult Wister rat to protect from oxidative stress induced damages by heat stress has been investigated in this study. Heat stress was induced maintaining body and testicular temperature at 43°C for 30min/day for 15 days using a hyperthermia induction chamber. Four groups of rats (n=6 per group) comprising of Group-I (control) -kept at 32°C, Group-II -exposed to heat stress alone, Group-III received RGJ (0.8ml/rat/day) alone and Group-IV -exposed to heat stress and received RGJ at same dose. Analysis of blood and testicular tissue exhibited significant reduction in serum testosterone, testicular superoxide dismutase, testicular catalase and testicular glutathione (all p < 0.001); whereas, significant rise in the level of serum corticosteroid, testicular lipid peroxidase and the apoptotic enzyme caspase-3 of testis (all p < 0.001) were observed along with substantial increase in testicular Hsp72 and Hsf-1, and decrease in 17β-HSD3 were noted in heat stressed rats compared to controls. In Group-IV rats, RGJ administration could restore these parameters to normal levels. The signs of retention were clear in Group-IV rats and found to be significantly different as compared to that of the Group-II rats. In testicular histology of rats exposed to heat stress alone revealed remarkable germ cell degeneration and tubular deformations which were prevented by RGJ treatment (Group-IV). The reduced number of sperm level in Group-II also restored in RGJ treatment (Group-IV). The above results indicate that consumption of RGJ may substantially protect testis from heat stress induce dysfunctions.

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 ofβ-glucosidase andβ-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.

Radioprotective effect of green tea and grape seed extracts mixture on gamma irradiation induced immune suppression in male albino rats

PURPOSE

Green tea extract (GTE) and grape seed extract (GSE) have antioxidant and radioprotective effects. The current study aimed to investigate the radioprotective effect of GTE and GSE mixture on radiation-induced immune suppression in rats.

METHOD

A total of 35 male albino rats were divided into five groups: group 1 (control rats). The 2nd and 3rd groups rats were exposed to a single dose of gamma radiation (5 and 10 Gy), respectively. The 4th and 5th groups of rats were gamma-irradiated with 5 and 10 Gy, respectively, then administrated by gavage with GTE and GSE mixture (100 mg: 200 mg/kg BW), respectively, for 14 consecutive days.

RESULTS

Gamma irradiation induced hematological, immunological and biochemical effects in rats. Treated rats with GTE and GSE mixture (1:2) showed an increase in concentrations of immune cells including CD4 and CD8. The level of pro-inflammatory cytokines Tumor necrosis factor-α and C-reactive protein elevated after γ-irradiation and significantly decreased by mixture administration. Moreover, groups treated with antioxidant mixture showed a significant increase in all hematological parameters and a significant decrease in cholesterol and triglyceride levels.

CONCLUSION

GTE and GSE mixture is a good radioprotector and immune modulator compound, indicating its possible use as an adjuvant during radiotherapy.

Evaluation of antioxidant activity of grapevine leaves extracts (Vitis labrusca) in liver of Wistar rats

The aim of this study was to evaluate the hepatoprotection of organic and conventional grapevine leaves extract (Vitis labrusca). The total polyphenol content and the isolate polyphenols by HPLC were evaluate. The animals received intraperitoneal injections of saline or extracts (conventional or organic - 30 mg/kg) for 14 days. On day 15, the rats received carbon tetrachloride (CCl4) or mineral oil (i.p.). After 4h, the animals were euthanized. The analysis of the liver enzymes activity (AST, ALT, GGT) was performed using serum, obtained by blood and the levels of lipid peroxidation (TBARS), protein oxidation (carbonyl), and the activity of antioxidant enzymes superoxide dismutase and catalase were analyzed in the liver. The results showed that the organic extract is richer in polyphenol and resveratrol than the conventional one. Both extracts prevent lipid peroxidation and protein oxidation generated by CCl4. Moreover, the extracts demonstrated ability to modulate the activity of SOD and CAT, as well as to establish a balance in the ratio of SOD/CAT. We also found that the CCl4 increased the levels of AST and GGT, and that both extracts prevent this. These results indicate that grapevine leaves extracts, both, organic and conventional, can prevent liver disorders.

Oral hepatoprotective ability evaluation of purple sweet potato anthocyanins on acute and chronic chemical liver injuries

In recent years, chemical liver injury cases increased significantly in Asian countries, and the imbalance in redox system was believed to be the main cause. Purple sweet potato anthocyanins (PSPA) have been shown to exert antioxidant activity and oxidative-stress-associated functional protein modulation through various signaling pathways, so it is considered to have the potential of liver injury preventive activity. In order to evaluate the hepatoprotective potency of PSPA according to its free radical scavenging and antioxidant effects, three acute chemical liver injury models were set up with ethanol, acetaminophen and carbon tetrachloride. PSPA at moderate and high doses obviously attenuated the tested serum biomarker levels and liver index in our experiments. Besides, one chronic liver injury model set up with carbon tetrachloride was also applied, in which PSPA was orally administrated after the liver damage had been formed. Both the serum biomarker levels and histopathological analysis showed that PSPA was able to attenuated chronic liver injury. Our experimental results demonstrated the potential of PSPA as an oral hepatoprotective agent against chemical liver injury from food plant.

Potential ergogenic activity of grape juice in runners

Recent studies have indicated that certain food products have ergogenic potential similar to that of sports supplements. The present study aimed to investigate the potential ergogenic effect of integral purple grape juice on the performance of recreational runners. Twenty-eight volunteers of both sexes (age, 39.8 ± 8.5 years; peak oxygen consumption, 43.2 ± 8.5 mL/(kg·min)) were randomized into either a group that received grape juice (grape juice group (GJG), n = 15; 10 mL/(kg·min) for 28 days) or a group that received an isocaloric, isoglycemic, and isovolumetric control beverage (control group (CG), n = 13). A time-to-exhaustion exercise test, anaerobic threshold test, and aerobic capacity test were performed, together with assessments of markers of oxidative stress, inflammation, immune response, and muscle injury, performed at baseline and 48 h after the supplementation protocol. The GJG showed a significant increase (15.3%) in running time-to-exhaustion (p = 0.002) without significant improvements in either anaerobic threshold (3.6%; p = 0.511) or aerobic capacity (2.2%; p = 0.605). In addition, GJG exhibited significant increases in total antioxidant capacity (38.7%; p = 0.009), vitamin A (11.8%; p = 0.016), and uric acid (28.2%; p = 0.005), whereas α-1-acid glycoprotein significantly decreased (20.2%; p = 0.006) and high-sensitivity C-reactive protein levels remained unchanged. In contrast, no significant changes occurred in any of these variables in the CG. In conclusion, supplementation with purple grape juice shows an ergogenic effect in recreational runners by promoting increased time-to-exhaustion, accompanied by increased antioxidant activity and a possible reduction in inflammatory markers.

Review of natural products with hepatoprotective effects

The liver is one of the most important organs in the body, performing a fundamental role in the regulation of diverse processes, among which the metabolism, secretion, storage, and detoxification of endogenous and exogenous substances are prominent. Due to these functions, hepatic diseases continue to be among the main threats to public health, and they remain problems throughout the world. Despite enormous advances in modern medicine, there are no completely effective drugs that stimulate hepatic function, that offer complete protection of the organ, or that help to regenerate hepatic cells. Thus, it is necessary to identify pharmaceutical alternatives for the treatment of liver diseases, with the aim of these alternatives being more effective and less toxic. The use of some plants and the consumption of different fruits have played basic roles in human health care, and diverse scientific investigations have indicated that, in those plants and fruits so identified, their beneficial effects can be attributed to the presence of chemical compounds that are called phytochemicals. The present review had as its objective the collecting of data based on research conducted into some fruits (grapefruit, cranberries, and grapes) and plants [cactus pear (nopal) and cactus pear fruit, chamomile, silymarin, and spirulina], which are consumed frequently by humans and which have demonstrated hepatoprotective capacity, as well as an analysis of a resin (propolis) and some phytochemicals extracted from fruits, plants, yeasts, and algae, which have been evaluated in different models of hepatotoxicity.

In vitro antioxidant capacity of tea of Echinodorus grandiforus, “leather hat,” in Wistar rat liver

Oxidative stress has been considered as one of the factors responsible for hepatic diseases, which sometimes require new ways of treatment. The present study aimed to evaluate the in vitro antioxidant capacity of the tea of Echinodorus grandiforus (“leather hat” plant) in rat liver. Different preparations of tea were evaluated for phenolic composition, antioxidant activity by DPPH assay and ability to inhibit lipid peroxidation induced by copper sulfate. The antioxidant activity was assessed in liver tissue treated with sodium azide in the presence or absence of tea by assays for lipid peroxidation (TBARS), protein oxidation (carbonyl) and the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD). The results show that different preparations of tea are important sources of polyphenols and contain theobromine, catechin and vitexin. Furthermore, the results indicate that this tea exhibits an antioxidant activity by its ability to scavenge DPPH radical. Different preparations of tea prevented damage to lipids and proteins induced by sodium azide, as well as assisting in restoring CAT and SOD activities. Thus, it can be seen that E. grandiforus tea had antioxidant activity in serum and liver being able to prevent oxidative damages generated by sodium azide.

Hepatoprotective and Antioxidant Potential of Organic and Conventional Grape Juices in Rats Fed a High-Fat Diet

The objective of this study was to investigate the antioxidant and hepatoprotective effect of the chronic use of conventional (CGJ) or organic (OGJ) grape juice from the Bordeaux variety grape on oxidative stress and cytoarchitecture in the liver of rats supplemented with a high-fat diet (HFD) for three months. The results demonstrated that HFD induced an increase in thiobarbituric acid-reactive substances (TBARS), catalase (CAT) activity and 2′,7′-dihydrodichlorofluorescein (DCFH) oxidation and a decrease in sulfhydryl content and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. HFD also induced hepatocellular degeneration and steatosis. These alterations were prevented by CGJ and OGJ, where OGJ was more effective. Therefore, it was concluded that HFD induced oxidative stress and liver damage and that the chronic use of grape juice was able to prevent these alterations.

Effect of black grape juice against heart damage from acute gamma TBI in rats

The aim of this study was to evaluate the potential positive effect of black grape juice (BGJ) on lipid peroxidation considering Total Body Irradiation (TBI) in Wistar rats. As a potential feasible means of evaluation in situ, blood serum lactate dehydrogenase (LDH) levels were evaluated as a marker for heart damage from acute radiation syndrome (ARS). Twenty rats were divided into four groups, two of them being irradiated by gamma-rays from a Co-60 source. Animals were treated by gavage with 2 mL per day of BGJ or placebo for one week before and 4 days after 6 Gy whole body gamma-irradiation, when they were euthanasiated. LDH on serum and lipid peroxidation on heart tissue were evaluated. High concentration of metabolites from lipid peroxidation in heart, and high LDH level on serum were found only in gamma-irradiated group given placebo, mainly at the first 24 h after radiation. Phytochemical analysis of BGJ was performed by determining total phenolics, flavonoids, and tannins followed by a high-performance liquid chromatography (HPLC/DAD) analysis, which showed resveratrol as the major constituent. Results suggest that BGJ is a good protective candidate compound against heart damage from ARS and its effects suggest its use as a radiomodifier.

Antioxidant and anti-inflammatory in vitro activities of phenolic compounds from tropical highland blackberry (Rubus adenotrichos)

This study evaluates the antioxidant and anti-inflammatory activities in a polyphenol extract from blackberries. The antioxidant activity measured via oxygen radical absorbance capacity (ORAC) was higher for the blackberry extract (4339 ± 144 μM TE/g) than for quercetin and ellagic acid. The blackberry phenolic compounds protected liposomes and liver homogenates against lipid peroxidation; in both models, the antioxidant activity (IC₅₀ = 7.0 ± 0.5 and 20.3 ± 4.2 μg/mL, respectively) was greater than that found with Trolox. The extract inhibited superoxide production by NADPH oxidase in THP-1 cells and nitrite production in J774A.1 cells stimulated with LPS+IFNγ, with nitrite production decreasing after 4 h of incubation with the extract, mainly through a strong scavenging activity. However, 24 h of treatment reduced the amount of nitrites (IC₅₀ = 45.6 ± 1.2 μg/mL) because of a down-regulation of iNOS protein expression, as demonstrated by Western blotting. The inhibitory activities found in blackberry phenols suggest a potential beneficial effect against oxidative stress and inflammatory processes.

Antioxidant effect of organic purple grape juice on exhaustive exercise

This study aimed to assess the potential protective effect of organic purple grape juice (PGJ) on oxidative stress produced by an exhaustive exercise bout in rats. To test this hypothesis, rats were acutely treated with organic PGJ (Vitis labrusca) and subsequently submitted to an exhaustive exercise bout. Parameters of oxidative stress, such as thiobarbituric acid reactive species (TBARS) levels, 2′,7′,-dichlorofluorescein diacetate (DCFH-DA) oxidation, and nonprotein sulfhydryl levels (NP-SH) in the brain, skeletal muscle, and blood, were evaluated. Enzyme activity of Na+,K+-ATPase, Ca2+-ATPase, and δ-aminolevulinate dehydratase (δ-ALA-D) in the brain, skeletal muscle, and blood were also assayed. Statistical analysis showed that the exhaustive exercise bout increased TBARS levels and DCFH-DA oxidation, and decreased NP-SH levels in rat tissue. Ca2+-ATPase activity was increased in groups exposed to both exercise and PGJ treatment. The results indicate that organic PGJ intake was able to protect against the oxidative damage caused by an exhaustive exercise bout in different rat tissues.

Purple grape juices prevent pentylenetetrazol-induced oxidative damage in the liver and serum of Wistar rats

Oxidative damages in hepatocytes may be caused by epilepsy and/or anticonvulsant drugs. Epilepsy is one of the most common neurological disorders, characterized by recurrent seizures, which may increase the content of reactive oxygen species. Organic and conventional grape juices are rich in polyphenols, compounds with important antioxidant activity. It is hypothesized that organic and conventional purple grape juices may have protective effect against oxidative damage induced by pentylenetetrazole (PTZ) (a standard convulsant drug) in the liver and serum of Wistar rats. Animals (n = 16 in each group) received, by gavage, saline, organic grape juice or conventional grape juice (10 μL/g of body weight) for 17 days. Subsequently, half of the rats in each group received PTZ (60 mg/kg). After 30 minutes, the animals were euthanized by decapitation. Liver and blood samples were isolated to evaluate oxidative parameters (lipid and protein oxidation, nitric oxide metabolite content, antioxidant defenses, and protein sulfhydryl content). The results of this study showed that although organic juice contains higher polyphenol content than conventional juice, both juices conferred protection against lipid and protein oxidative damage and limited the increase in PTZ-induced nitric oxide metabolite content in the liver and serum. In addition, both juices inhibited the PTZ-induced reduction in enzymatic antioxidant defenses (superoxide dismutase and catalase activities) and sulfhydryl protein content in the liver and serum. In summary, both organic and conventional grape juices were able to reduce oxidative damage induced by PTZ in the liver and serum of Wistar rats.

Hepatoprotective, cardioprotective, and renal-protective effects of organic and conventional grapevine leaf extracts on Wistar rat tissues

The purpose of this study was to evaluate the beneficial effects of organic and conventional grapevine (Vitis labrusca L.) leaf extracts in reducing hydrogen peroxide-induced stress in the liver, heart and kidney of Wistar rats by measuring lipids and proteins damages (carbonyl assay), as well as the activity of the antioxidant enzymes superoxide dismutase and catalase. The preincubation with 5 mg/mL of organic and conventional grapevine (Vitis labrusca L.) leaf extracts prevented both lipids and proteins oxidative damages in all tissues analyzed. The organic leaf extract was able to restore superoxide dismutase (kidney and liver) and catalase (heart) activities, which were modified by the treatment with H(2)O(2). The conventional extract was able to restore only the catalase activity in liver and heart tissues. The beneficial effects of the V labrusca leaf extract shown in this study could probably be important for formulating dietary supplements, as well as for developing new ingredients with improved antioxidant properties from other plant sources.

Mineral content is related to antioxidant and antimutagenic properties of grape juice

Grape juices are an important source of food antioxidants. Unfortunately, there is little data about the mineral composition and the antioxidant, mutagenic and antimutagenic activities of grape juice in eukaryote cells. We evaluated the mineral contents (Mg, Ca, Mn, Fe, Cu, Zn, Si, S, Cl) of grape juices, the antioxidant, mutagenic and/or antimutagenic activities of the juices in the yeast Saccharomyces cerevisiae, and looked for a possible association between mineral content and antioxidant, mutagenic and/or antimutagenic activities of juice samples. Eight commercial grape juices, four purple (Bordo variety) and four white (Niagara variety), were evaluated. Most of the minerals were in similar concentrations in purple and white grape juices, except for calcium and copper; purple grapes had more calcium content and white grapes had more copper content. All grape juices had important antioxidant and antimutagenic activities in S. cerevisiae and prevented the oxidative damage provoked by hydrogen peroxide (P < 0.05). Positive correlations (P < 0.05) were observed between antioxidant and antimutagenic activities and mineral content. In this context, we concluded that the grape juices, white and purple, are an important mineral source, and these contents explain, in part, the important antioxidant and antimutagenic activities.

Anthocyanins block ischemia-induced apoptosis in the perfused heart and support mitochondrial respiration potentially by reducing cytosolic cytochrome c

Anthocynanins, found in fruits and vegetables, have a variety of protective properties, which have generally been attributed to their antioxidant capacity. However, antioxidants are generally strong reductants, and some reductants have been found to block apoptosis by reducing cytosolic cytochrome c, which prevents caspase activation. We tested the ability of various anthocyanins: to reduce cytochrome c, to support cytochrome c-induced mitochondrial respiration and to inhibit apoptosis induced by heart ischemia. Anthocyanins such as delphinidin-3-glucoside (Dp3G) and cyanidin-3-glucoside (Cy3G) were able to reduce cytochrome c directly and rapidly, whereas pelargonidin-3-glucoside (Pg3G), malvinidin-3-glucoside (Mv3G) and peonidin-3-glucoside (Pn3G) had relatively low cytochrome c reducing activities. Dp3G and Cy3G but not Pg3G supported mitochondrial state 4 respiration in the presence of exogenous cytochrome c. Pre-perfusion of hearts with 20 μM Cy3G but not Pg3G prevented ischemia-induced caspase activation. This suggests that the ability of anthocyanins to block caspase activation may be due to their ability to reduce cytosolic cytochrome c. This article is part of a Directed Issue entitled: Bioenergetic dysfunction, adaptation and therapy.

Grape antioxidant dietary fibre prevents mitochondrial apoptotic pathways by enhancing Bcl-2 and Bcl-xL expression and minimising oxidative stress in rat distal colonic mucosa

Grape antioxidant dietary fibre (GADF) is a grape product rich in dietary fibre and natural antioxidants. We reported previously that GADF intake reduced apoptosis and induced a pro-reducing shift in the glutathione (GSH) redox status of the rat proximal colonic mucosa. The aim of the study was to elucidate the molecular mechanisms responsible for the anti-apoptotic effect of GADF and their association with the oxidative environment of the distal colonic mucosa. The ability of GADF to modify colonic crypt cell proliferation was also investigated. Male Wistar rats (n 20) were fed with diets containing either cellulose (control group) or GADF (GADF group) as fibre for 4 weeks. GADF did not modify cell proliferation but induced a significant reduction of colonic apoptosis. The anti-apoptotic proteins Bcl-2 (B-cell lymphoma-2) and Bcl-xL (B-cell lymphoma extra large) were up-regulated in the mitochondria and down-regulated in the cytosol of the GADF mucosa, whereas the opposite was found for the pro-apoptotic protein Bax (Bcl-2-associated X protein), leading to an anti-apoptotic shift in the pattern of expression of the Bcl-2 family. Cytosolic cytochrome c and cleaved caspase-3 levels and caspase-3 activity were reduced by GADF. The modulation of the antioxidant enzyme system and the increase of the cytosolic GSH:glutathione disulfide (GSSG) ratio elicited by GADF helped to reduce oxidative damage. The cytosolic GSH:GSSG ratio was negatively related to apoptosis. These results indicate that GADF acts on the expression of the pro- and anti- apoptotic Bcl-2 proteins, attenuating the mitochondrial apoptotic pathway in the distal colonic mucosa. This effect appears to be associated with the antioxidant properties of GADF.

Evaluation of the potential protective effects of ad libitum black grape juice against liver oxidative damage in whole-body acute X-irradiated rats

AIMS

The aim of this study was to evaluate the potential protective effects of ad libitum black grape (Vitis labrusca) juice against liver oxidative damage in whole-body acute X-irradiated rats.

MAIN METHODS

Animals were fed ad libitum and drank voluntarily black grape juice or placebo (isocaloric glucose and fructose solution) for 6 days before and 15 days following a 6 Gy X-irradiation from a 200 kV machine.

KEY FINDINGS

Irradiated animals receiving placebo showed a significant increase in the concentration of thiobarbituric acid-reactive substances (TBARS), a marker of lipid peroxidation, as well as a significant decrease in both Cu/Zn superoxide dismutase (Cu/ZnSOD) and glutathione peroxidase (GPx) activity and reduced glutathione concentration (GSH). Black grape juice supplementation resulted in a reversal of lipid peroxidation, Cu/ZnSOD activity, and GSH concentration, towards values not significantly differing from those in non-irradiated, placebo-supplemented rats. Poly(ADP-ribose) polymerase (PARP-1) and Cu/ZnSOD changes in protein expression were observed for irradiated rats. No change in p53 expression or DNA fragmentation was found.

SIGNIFICANCE

Ad libitum black grape juice intake is able to restore the liver primary antioxidant system against adverse effects due to whole-body acute X-irradiation in rats after 15 days post-irradiation. The results support using antioxidant supplements as a preventive tool against radiation-induced harm.

Resveratrol and liver disease: from bench to bedside and community

Liver diseases incorporate several maladies, which can range from benign histological changes to serious life-threatening conditions. These may include inborn metabolic disease, primary and metastatic cancers, alcoholic cirrhosis, viral hepatitis and drug-induced hepatotoxicity. Liver disease remains a major cause of morbidity and mortality with significant economic and social costs. Several novel approaches are currently being studied which may provide a better therapeutic outcome. The use of naturally occurring phytochemicals, some of them obtained from dietary sources, in the amelioration of illness have recently gained considerable popularity. These agents, having anti-oxidant and anti-inflammatory properties, provide a safe and effective means of ameliorating chronic disease. Resveratrol, a grape polyphenol, has shown considerable promise as a therapeutic agent in the treatment of the aforementioned liver ailments. Several studies have highlighted the hepatoprotective properties of resveratrol. Resveratrol has been shown to prevent hepatic damage because of free radicals and inflammatory cytokines, induce anti-oxidant enzymes and elevate glutathione content. Resveratrol has also been shown to modulate varied signal transduction pathways implicated in liver diseases. This review critically examines the current preclinical in vitro and in vivo studies on the preventive and therapeutic effects of resveratrol in liver diseases. The review highlights the pharmacological mechanisms involved in mediating the aforementioned effects. Toxicity, pharmacokinetics and clinical bioavailability of resveratrol are also reviewed in this article. The challenges involved, future directions and novel approaches such as site-specific drug delivery in the use of resveratrol for the prevention and treatment of liver disease are also discussed.

Grape antioxidant dietary fibre reduced apoptosis and induced a pro-reducing shift in the glutathione redox state of the rat proximal colonic mucosa

Grape antioxidant dietary fibre (GADF) is a grape product rich in dietary fibre and natural antioxidants. We showed previously that the GADF intake induced an epithelial hypoplasia in the rat colonic mucosa. In the present study, we propose that the antioxidant effect of GADF could modulate mucosal apoptosis via modulation of the cellular redox environment. Male Wistar rats (n20) were fed with diets containing either cellulose (control diet group) or GADF (GADF diet group) as fibre for 4 weeks. The GSH:GSSG ratio, the redox state of the GSSG/2GSH couple (Ehc), the mitochondrial and/or cytosolic antioxidant enzyme activities (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)), lipid peroxidation (LPO) and apoptosis were evaluated. GADF enhanced the cytosolic GSH:GSSG ratio, shifting the redox potential (Ehc) to a more pro-reducing status. Decreased Cu,ZnSOD:CAT, Cu,ZnSOD:GPx and MnSOD:GPx ratios could indicate an enhanced capacity for reducing H2O2, contributing to decreased cytosolic LPO. Reduced apoptosis in GADF-treated mucosa was inversely related to MnSOD activity. Furthermore, apoptosis increased directly as GSSG content increased. These results suggest that the reduction in apoptosis associated with GADF intake may be due to a modulation of the glutathione redox system and endogenous antioxidant enzymes.