Erratum: Nutritional habits and free grazing regimen of productive animals along with specific ingredients are influential factors for the antioxidant properties of milk: From farm to market.

[This corrects the article DOI: 10.3892/br.2020.1301.].

The flavoring and not the nicotine content is a decisive factor for the effects of refill liquids of electronic cigarette on the redox status of endothelial cells.

Electronic cigarettes are constantly gaining ground as they are considered less harmful than conventional cigarettes, and there is also the perception that they may serve as a potential smoking cessation tool. Although the acute effects of electronic cigarette use have been extensively studied, the long-term potential adverse effects on human health remain largely unknown. It has been well-established that oxidative stress is involved in the development of various pathological conditions. So far, most studies on e-cigarettes concern the effects on the respiratory system while fewer have focused on the vascular system. In the present study, we attempted to reveal the effects of electronic cigarette refill liquids on the redox state of human endothelial cells (EA.hy926 cell line). For this purpose, the cytotoxic effect of three e-liquids with different flavors (tobacco, vanilla, apple/mint) and nicotine concentrations (0, 6, 12, 18 mg/ml) were initially examined for their impact on cell viability of EA.hy926 cells. Then, five redox biomarkers [reduced form of glutathione (GSH), reactive oxygen species (ROS), total antioxidant capacity (TAC), thiobarbituric acid reactive substances (TBARS) and protein carbonyls (CARBS)] were measured. The results showed a disturbance in the redox balance in favor of free radicals in tobacco flavored e-liquids while vanilla flavored e-liquids exhibited a more complex profile depending on the nicotine content. The most interesting finding of the present study concerns the apple/mint flavored e-liquids that seemed to activate the cellular antioxidant defense and, thus, to protect the cells from the adverse effects of free radicals. Conclusively, it appears that the flavorings and not the nicotine content play a key role in the oxidative stress-induced toxicity of the e-liquids.

Whey protein boosts the antioxidant profile of rats by enhancing the activities of crucial antioxidant enzymes in a tissue-specific manner.

Whey protein, a by-product of cheese industry, is harmful for the environment (i.e., surface and subterranean waters, soil) and, therefore, for humans due to its high polluting burden. Concomitantly, it has been reported that it is a mixture with potent antioxidant action since it is rich in cysteine residues, which are necessary for glutathione synthesis in vivo. On this basis, this study intended to examine the role of whey protein on the intensification of tissue antioxidant arsenal. To this end, a dose of sheep/goat whey protein equal to 1 g/kg of body weight/day dissolved in drinking water was administered to rats for 28 consecutive days. According to our findings, whey protein improved the antioxidant profile of liver, small intestine, lung and muscle whereas it did not affect the redox state of kidney. Our results were based on the alterations found in the protein expression of glutamate cysteine ligase, catalase and superoxide dismutase-1 measured in all tissues and the activity of glutathione S-transferase evaluated in muscle. Although tissue-specific, it is obvious that the action of whey protein is biologically beneficial and could serve as a biofunctional constituent for foods able to improve redox profile when administered against redox-related diseases.

Nutritional habits and free grazing regimen of productive animals along with specific ingredients are influential factors for the antioxidant properties of milk: From farm to market.

Milk is a fundamental product of animal origin for human health and well-being. It possesses crucial biological properties, which depend on its composition and production methodology. To this end, one of the aims of the present study was to assess the impact of the nutritional and dwelling patterns of productive animals on the antioxidant potency of their generated milk. Thus, samples of sheep milk were collected for 30 consecutive days during the spring months from 5 different farms with different traits and its antioxidant activity was measured. Furthermore, this study aimed to evaluate the antioxidant capacity of 15 commercially available milk samples of different animal origin (i.e., cow and buffalo) and type (i.e., full-fat, light and chocolate) derived from 5 different companies. For all the experiments, the assay that examines the ability of the milk samples to reduce the DPPH• radical was used. It was thus found that the free-grazing regimen of the farm sheep dwelling at high altitude resulted in the production of milk with a greater antioxidant potential. On the other hand, it was also found that the samples of chocolate milk exhibited notably mote potent antioxidant activity than the full-fat and light samples, obviously due to the excessively high composition in antioxidant molecules present in cocoa. From this study that holistically examined the antioxidant properties of milk derived from three different productive animal species, it becomes evident that the nutritional and grazing practices, as well as specific ingredients (i.e., cocoa) lead to the generation of milk with high added biological value.

Effect of crocin on antioxidant gene expression, fibrinolytic parameters, redox status and blood biochemistry in nicotinamide-streptozotocin-induced diabetic rats.

BACKGROUND: Diabetes is regarded as an epidemiological threat for the twenty-first century. Phytochemicals with known pharmaceutical properties have gained interest in the field of alleviating secondary complications of diseases. Such a substance is crocin, a basic constituent of saffron (Crocus sativus). The present study aimed at examining the beneficial effects of per os crocin administration on the antioxidant status, blood biochemical profile, hepatic gene expression and plasminogen activator inhibitor-1 activity (PAI-1) in the liver, kidney and plasma (an important marker of pre-diabetic status and major factor of thrombosis in diabetes) of healthy rats, as well as of rats with nicotinamide-streptozotocin-induced diabetes. RESULTS: Diabetes disrupted the oxidation-antioxidation balance, while crocin improved the antioxidant state in the liver by significantly affecting SOD1 gene expression and/or by restoring SOD and total antioxidant capacity (TAC) levels. In the kidney, crocin improved hydrogen peroxide decomposing activity and TAC. In blood, hepatic transaminases ALT and AST decreased significantly, while there was a trend of decrease regarding blood urea nitrogen (BUN) levels. The expression of PAI-1 gene was affected in the liver by the dose of 50 mg kg-1. CONCLUSIONS: Crocin treatment contributed in restoring some parameters after diabetes induction, primarily by affecting significantly hepatic transaminases ALT and AST, SOD1 and PAI-1 gene expression and nephric H2O2 decomposing activity. In conclusion, crocin did contribute to the alleviation of some complications of diabetes.

A mixture of routinely encountered xenobiotics induces both redox adaptations and perturbations in blood and tissues of rats after a long-term low-dose exposure regimen: The time and dose issue.

Exposure of humans to xenobiotic mixtures is a continuous state during their everyday routine. However, the majority of toxicological studies assess the in vivo effects of individual substances rather than mixtures. Therefore, our main objective was to evaluate the impact of the 12- and 18-month exposure of rats to a mixture containing 13 pesticides, food, and life-style additives in three dosage levels (i.e. 0.0025 × NOAEL, 0.01 × NOAEL, and 0.05 × NOAEL), on redox biomarkers in blood and tissues. Our results indicate that the exposure to the mixture induces physiological adaptations by enhancing the blood antioxidant mechanism (i.e., increased glutathione, catalase and total antioxidant capacity and decreased protein carbonyls and TBARS) at 12 months of exposure. On the contrary, exposure to the 0.05 × NOAEL dose for 18 months induces significant perturbations in blood and tissue redox profile (i.e., increased carbonyls and TBARS). This study simulates a scenario of real-life risk exposure to mixtures of xenobiotics through a long-term low-dose administration regimen in rats. The results obtained could support, at least in part, the necessity of introducing testing of combined stimuli at reference doses and long term for the evaluation of the risk from exposure to chemicals.

A Polyphenolic Extract from Olive Mill Wastewaters Encapsulated in Whey Protein and Maltodextrin Exerts Antioxidant Activity in Endothelial Cells.

The aim of the present study was to compare maltodextrin and whey protein as encapsulation carriers for olive mill wastewater (OMWW) phenolic extract for producing antioxidant powder, by using spray drying under 17 different conditions. In some samples, gelatin was also added in the encapsulation mixture. The antioxidant activity was assessed in vitro by using the DPPH•, ABTS•+, reducing power and DNA plasmid strand breakage assays. The results showed that both materials were equally effective for producing antioxidant powder, although by using different conditions. For example, inlet/outlet temperature of the spray drying did not seem to affect the maltodextrin samples' antioxidant activity, but whey protein samples showed better antioxidant activity at lower temperatures. Gelatin use decreased antioxidant activity, especially in whey protein samples. The two most potent samples, one encapsulated in maltodextrin and the other in whey protein, were examined for their antioxidant effects in human endothelial cells by assessing glutathione (GSH) and reactive oxygen species (ROS) levels. Both samples significantly enhanced the antioxidant molecule of GSH, while maltodextrin sample also decreased ROS. The present findings suggested both materials for encapsulation of OMWW extract for producing antioxidant powder which may be used in food products, especially for the protection from ROS-induced endothelium pathologies.

Polyphenolic Composition of Rosa canina, Rosa sempervivens and Pyrocantha coccinea Extracts and Assessment of Their Antioxidant Activity in Human Endothelial Cells.

The aim of the present study was the investigation of the antioxidant activity of plant extracts from Rosa canina, Rosa sempervivens and Pyrocantha coccinea. The results showed that the bioactive compounds found at higher concentrations were in the R. canina extract: hyperoside, astragalin, rutin, (+)-catechin and (-)-epicatechin; in the R. sempervirens extract: quinic acid, (+)-catechin, (-)-epicatechin, astragalin and hyperoside; and in the P. coccinea extract: hyperoside, rutin, (-)-epicatechin, (+)-catechin, astragalin, vanillin, syringic acid and chlorogenic acid. The total polyphenolic content was 290.00, 267.67 and 226.93 mg Gallic Acid Equivalent (GAE)/g dw, and the total flavonoid content 118.56, 65.78 and 99.16 mg Catechin Equivalent (CE)/g dw for R. caninna, R. sempervirens and P. coccinea extracts, respectively. The extracts exhibited radical scavenging activity in DPPH and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS)•⁺ assays and protection from ROO•-induced DNA damage in the following potency order: R. canina > R. sempervirens > P. coccinea. Finally, treatment with R. canina and P. coccinea extract significantly increased the levels of the antioxidant molecule glutathione, while R. canina extract significantly decreased Reactive Oxygen Species (ROS) in endothelial cells. The results herein indicated that the R. canina extract in particular may be used for developing food supplements or biofunctional foods for the prevention of oxidative stress-induced pathological conditions of endothelium.

The Strong Antioxidant Sheep/Goat Whey Protein Protects Against mTOR Overactivation in Rats: A Mode of Action Mimicking Fasting.

Whey protein, a by-product of the cheese industry, can be putatively used as a functional food due to its beneficial health properties. The main objective of the present study was to assess in vivo the effect of a sheep/goat whey protein on the plasma amino acid profile and mammalian target of rapamycin (mTOR), a regulator of skeletal myogenesis. A control group was fed with a standard commercial diet while the experimental group received a standard commercial diet plus sheep/goat whey protein for 28 days. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was conducted to determine plasma amino acid levels while the expression of p70-S6 Kinase 1 (p70-S6K1) in liver and quadriceps muscles was quantified and used as a biomarker of mTOR activity. The results obtained showed a decrease in the levels of essential and branched-chain amino acids (BCAAs) in the experimental group. Furthermore, p70-S6K1 expression was decreased in the liver of rats consumed whey protein. In conclusion, the reduction of amino acid levels and the concomitant inactivation of mTOR imply that whey could potentially act protectively against disorders induced by mTOR overactivation. Intriguingly, this mode of action mimics fasting, an approach with established advantageous health effects.

Extracts from the Mediterranean Food Plants Carthamus lanatus, Cichorium intybus, and Cichorium spinosum Enhanced GSH Levels and Increased Nrf2 Expression in Human Endothelial Cells.

The Mediterranean diet is considered to prevent several diseases. In the present study, the antioxidant properties of six extracts from Mediterranean plant foods were assessed. The extracts' chemical composition analysis showed that the total polyphenolic content ranged from 56 to 408 GAE mg/g dw of extract. The major polyphenols identified in the extracts were quercetin, luteolin, caftaric acid, caffeoylquinic acid isomers, and cichoric acid. The extracts showed in vitro high scavenging potency against ABTS•+ and O2 •- radicals and reducing power activity. Also, the extracts inhibited peroxyl radical-induced cleavage of DNA plasmids. The three most potent extracts, Cichorium intybus, Carthamus lanatus, and Cichorium spinosum, inhibited OH•-induced mutations in Salmonella typhimurium TA102 cells. Moreover, C. intybus, C. lanatus, and C. spinosum extracts increased the antioxidant molecule glutathione (GSH) by 33.4, 21.5, and 10.5% at 50 µg/ml, respectively, in human endothelial EA.hy926 cells. C. intybus extract was also shown to induce in endothelial cells the transcriptional expression of Nrf2 (the major transcription factor of antioxidant genes), as well as of antioxidant genes GCLC, GSR, NQO1, and HMOX1. In conclusion, the results suggested that extracts from edible plants may prevent diseases associated especially with endothelium damage.

Assessment of the antioxidant and antimutagenic activity of extracts from goji berry of Greek cultivation.

The aim of this study was to assess the antioxidant and antimutagenic activities of ultrasound assisted aqueous extracts from dry goji berry fruits cultivated in Greece. The extracts' free radical scavenging activity was assessed by the DPPH• and ABTS•+ assays. The results from both assays demonstrated that the extracts exhibited strong radical scavenging activity with IC50 values ranging from 1.29 to 3.00 mg/ml for DPPH• and from 0.39 to 1.10 mg/mL for ABTS•+ assay. The investigated extracts also inhibited free radical-induced DNA damage induced by peroxyl (ROO•) radicals with IC50 ranging from 0.69 to 6.90 mg/mL. Τhe antioxidant activity of the goji berry extract exhibited the highest potency in the above assays was also examined in muscle cells. In particular, muscle C2C12 cells were treated with the selected extract at non cytotoxic concentrations for 24 h and four oxidative stress markers were measured: total reactive oxygen species (ROS), glutathione (GSH), lipid peroxidation and protein carbonyl levels. The results showed that the extract at 25 and 100 µg/mL increased GSH levels up to 189.5% and decreased lipid peroxidation and protein carbonyls by 21.8 and 29.1% respectively. The present study was the first on the antioxidant effects of ultrasound assisted aqueous extracts from goji berry fruits in muscle cells.

Six months exposure to a real life mixture of 13 chemicals' below individual NOAELs induced non monotonic sex-dependent biochemical and redox status changes in rats.

This study assessed the potential adverse health effects of long-term low-dose exposure to chemical mixtures simulating complex real-life human exposures. Four groups of Sprague Dawley rats were administered mixtures containing carbaryl, dimethoate, glyphosate, methomyl, methyl parathion, triadimefon, aspartame, sodium benzoate, calcium disodium ethylene diamine tetra-acetate, ethylparaben, butylparaben, bisphenol A, and acacia gum at doses of 0, 0.25, 1 or 5 times the respective Toxicological Reference Values (TRV): acceptable daily intake (ADI) or tolerable daily intake (TDI) in a 24 weeks toxicity study. Body weight gain, feed and water consumption were evaluated weekly. At 24 weeks blood was collected and biochemistry parameters and redox status markers were assessed. Adverse effects were observed on body weight gain and in hepatotoxic parameters such as the total bilirubin, alanine aminotransferase (ALT) and alkaline phosphatase (ALP), especially in low dose and affecting mainly male rats. The low dose group showed increased catalase activity both in females and males, whereas the high dose group exhibited decreased protein carbonyl and total antioxidant capacity (TAC) levels in both sex groups. Non-monotonic effects and adaptive responses on liver function tests and redox status, leading to non-linear dose-responses curves, are probably produced by modulation of different mechanisms.

Effects of sheep/goat whey protein dietary supplementation on the redox status of rats.

The purpose of the present study is to estimate the effects of sheep/goat whey protein dietary supplementation on the redox status of blood and tissues of rats. Twelve male Wistar rats were divided into the control group (standard commercial diet) and whey group [standard commercial diet + sheep/goat whey protein (1 g kg b.w/day)] (6 rats/group). The animals were maintainted on their respective diet for 28 days. At the end of the experimental period, reduced glutathione, catalase activity, total antioxidant capacity, thiobarbituric reactive substances, protein carbonyls and the decomposition rate of H2O2 were measured in blood and tissues of rats. According to the results, the rats fed with the sheep/goat whey protein exhibited improved antioxidant status and decreased free radical­induced toxic effects on lipids and proteins. Specifically, in blood, GSH and CAT levels were significantly increased while TBARS and protein carbonyl levels were significantly decreased compared to the control group. Regarding the effects on tissues, it was observed that GSH levels were significantly increased in small intestine, quadriceps muscle, pancreas and lung tissue compared to the control group. The decomposition rate of H2O2 was significantly decreased in liver, brain and quadriceps muscle, but was significantly increased in spleen tissue compared to the control group. TBARS levels were significantly decreased in liver, brain, quadriceps muscle, pancreas, lung and spleen tissue compared to the control group. Finally, protein carbonyl levels were significantly decreased in brain, small intestine, kidney, pancreas and spleen tissue compared to the control group. Thus, the present findings show the beneficial effects of sheep/goat whey protein, a by­product of cheese manufacturing, on the redox status in an in vivo model.

Enhancement of Antioxidant Mechanisms and Reduction of Oxidative Stress in Chickens after the Administration of Drinking Water Enriched with Polyphenolic Powder from Olive Mill Waste Waters.

The aim of the study was to examine the effects of a polyphenolic powder from olive mill wastewater (OMWW) administered through drinking water, on chickens' redox status. Thus, 75 chickens were divided into three groups. Group A was given just drinking water, while groups B and C were given drinking water containing 20 and 50 µg/ml of polyphenols, respectively, for 45 days. The antioxidant effects of the polyphenolic powder were assessed by measuring oxidative stress biomarkers in blood after 25 and 45 days of treatment. These markers were total antioxidant capacity (TAC), protein carbonyls (CARB), thiobarbituric acid reactive species (TBARS) and superoxide dismutase activity (SOD) in plasma, and glutathione (GSH) and catalase activity in erythrocytes. The results showed that CARB and TBARS were decreased significantly in groups B and C, and SOD decreased in group B compared to that in group A. TAC was increased significantly in group C and GSH was increased in group B, while catalase activity was increased in groups B and C compared to that in group A. In conclusion, this is the first study showing that supplementation of chickens with polyphenols from OMWW through drinking water enhanced their antioxidant mechanisms and reduced oxidative stress-induced damage.

Tissue specific effects of feeds supplemented with grape pomace or olive oil mill wastewater on detoxification enzymes in sheep.

The aim of the present study was to investigate the effects of livestock feed supplemented with grape pomace (GP) or olive oil mill wastewater (OMW) byproducts on the enzymatic activity and protein expression of antioxidants enzymes, in liver and spleen tissue of sheep. Thus, 36 male sheep of Chios breed were divided into 3 homogeneous groups, control group (n = 12), GP group (n = 12) and OMW group (n = 12), receiving standard or experimental feed. Liver and spleen tissues were collected at 42 and 70 days post-birth. The enzymatic activity of superoxide dismutase (SOD) and glutathione-s-transferase (GST) and also the protein expression of γ-synthase glutamyl custeine (γ-GCS) were determined in these tissues. The results showed GP group exhibited increased enzymatic activity of GST and protein expression of γ-GCS in liver compared to control group. In GP group's spleen, GST activity was increased compared to control but γ-GCS expression was not affected. In OMW group's liver, GST activity was increased and γ-GCS expression was reduced compared to control. In OMW group's spleen, GST activity was increased but GCS expression was not affected. SOD activity was not affected in both tissues either in GP or OMW group.

Development of an assay to assess genotoxicity by particulate matter extract.

The current study describes a method for assessing the oxidative potential of common environmental stressors (ambient air particulate matter), using a plasmid relaxation assay where the extract caused single-strand breaks, easily visualised through electrophoresis. This assay utilises a miniscule amount (11 µg) of particulate matter (PM) extract compared to other, cell­based methods (~3,000 µg). The negative impact of air pollution on human health has been extensively recognised. Among the air pollutants, PM plays an eminent role, as reflected in the broad scientific interest. PM toxicity highly depends on its composition (metals and organic compounds), which in turn has been linked to multiple health effects (such as cardiorespiratory diseases and cancer) through multiple toxicity mechanisms; the induction of oxidative stress is considered a major mechanism among these. In this study, the PM levels, oxidative potential, cytotoxicity and genotoxicity of PM in the region of Larissa, Greece were examined using the plasmid relaxation assay. Finally, coffee extracts from different varieties, derived from both green and roasted seeds, were examined for their ability to inhibit PM-induced DNA damage. These extracts also exerted an inhibitory effect on xanthine oxidase and catalase, but had no effect against superoxide dismutase. Overall, this study highlights the importance of assays for assessing the oxidative potential of widespread environmental stressors (PM), as well as the antioxidant capacity of beverages and food items, with the highlight being the development of a plasmid relaxation assay to assess the genotoxicity caused by PM using only a miniscule amount.

Increase in antioxidant activity by sheep/goat whey protein through nuclear factor-like 2 (Nrf2) is cell type dependent.

The aim of the present study was to investigate the molecular mechanisms through which sheep/goat whey protein exerts its antioxidant activity. Thus, it was examined whey protein's effects on the expression of transcription factor, nuclear factor-like 2 (Nrf2) and on the expression and activity of a number of antioxidant and phase II enzymes, superoxide dismutase (SOD), catalase (CAT), heme oxygenase 1 (HO-1), synthase glutamyl cysteine (GCS) and glutathione-s-transferase (GST), in muscle C2C12 and EA.hy926 endothelial cells. C2C12 and EA.hy926 cells were treated with sheep/goat whey protein (0.78 and 3.12 mg/ml) and incubated for 3, 6, 12, 18 and 24 h. Whey protein increased significantly the expression of Nrf2 only in EA.hy926 cells. Also, the expression of SOD, HO-1, CAT and the activity of SOD, CAT and GST were increased significantly in both cells types. The expression of GCS was increased significantly only in C2C12 cells. Sheep/goat whey protein was shown for the first time to exert its antioxidant activity through Nrf2-dependent mechanism in endothelial cells and Nrf2-independent mechanism in muscle cells. Thus, Nrf2 could be a target for food supplements containing whey protein in order to prevent oxidative stress damages and diseases related to endothelium.

Antioxidant Effects of Sheep Whey Protein on Endothelial Cells.

Excessive production of reactive oxygen species (ROS) may cause endothelial dysfunction and consequently vascular disease. In the present study, the possible protective effects of sheep whey protein (SWP) from tert-butyl hydroperoxide- (tBHP-) induced oxidative stress in endothelial cells (EA.hy926) were assessed using oxidative stress biomarkers. These oxidative stress biomarkers were glutathione (GSH) and ROS levels determined by flow cytometry. Moreover, thiobarbituric acid-reactive substances (TBARS), protein carbonyls (CARB), and oxidized glutathione (GSSG) were determined spectrophotometrically. The results showed that SWP at 0.78, 1.56, 3.12, and 6.24 mg of protein mL(-1) increased GSH up to 141%, while it decreased GSSG to 46.7%, ROS to 58.5%, TBARS to 52.5%, and CARB to 49.0%. In conclusion, the present study demonstrated for the first time that SWP protected endothelial cells from oxidative stress. Thus, SWP may be used for developing food supplements or biofunctional foods to attenuate vascular disturbances associated with oxidative stress.

Grape pomace extract exerts antioxidant effects through an increase in GCS levels and GST activity in muscle and endothelial cells.

In a previous study, we demonstrated that a grape pomace extract (GPE) exerted antioxidant activity in endothelial (EA.hy926) and muscle (C2C12) cells through an increase in glutathione (GSH) levels. In the present study, in order to elucidate the mechanisms responsible for the antioxidant activity of GPE, its effects on the expression of critical antioxidant enzymes, such as catalase (CAT), superoxide dismutase (SOD)1, heme oxygenase 1 (HO-1) and gamma-glutamylcysteine synthetase (GCS) were assessed in EA.hy926 and C2C12 cells. Moreover, the effects of GPE on CAT, SOD and glutathione S-transferase (GST) enzymatic activity were evaluated. For this purpose, the C2C12 and EA.hy926 cells were treated with GPE at low and non-cytotoxic concentrations (2.5 and 10 µg/ml for the C2C12 cells; 0.068 and 0.250 µg/ml for the EA.hy926 cells) for 3, 6, 12, 18 and 24 h. Following incubation, enzymatic expression and activity were assessed. The results revealed that treatment with GPE significantly increased GCS levels and GST activity in both the C2C12 and EA.hy926 cells. However, GPE significantly decreased CAT levels and activity, but only in the muscle cells, while it had no effect on CAT levels and activity in the endothelial cells. Moreover, treatment with GPE had no effect on HO-1 and SOD expression and activity in both cell lines. Therefore, the present results provide further evidence of the crucial role of GSH systems in the antioxidant effects exerted by GPE. Thus, GPE may prove to be effective for use as a food supplement for the treatment of oxidative stress-induced pathological conditions of the cardiovascular and skeletal muscle systems, particularly those associated with low GSH levels.

Antioxidant effects of whey protein on muscle C2C12 cells.

In the present study, the in vitro scavenging activity of sheep whey protein against free radicals, as well as its reducing power were determined and compared with that of beef protein, soy protein and cow whey protein. Moreover, the possible protective effects of sheep whey protein from tert-butyl hydroperoxide (tBHP)-induced oxidative stress in muscle C2C12 cells were determined by assessing oxidative stress markers by flow cytometry and spectrophotometry. The results showed that sheep whey protein scavenged DPPH, ABTS(+) and OH radicals with IC50 values of 3.1, 4.1 and 1.8 mg of protein/ml. Moreover, the reducing power activity assessed with potassium ferricyanide of sheep whey protein was 1.3mg/ml. As regards to the antioxidant effects in muscle cell line, sheep whey protein at 0.78, 1.56, 3.12 and 6.24 mg of protein/ml increased GSH levels up to 138%, lowered TBARS levels up to 25% and decreased ROS levels up to 41.4%.