Antioxidants in relation to lipid peroxidation

Muscle strength, quantity and quality and muscle fat quantity and their association with oxidative stress in patients with facioscapulohumeral muscular dystrophy: Effect of antioxidant supplementation

The purpose of this study was to identify causes of quadriceps muscle weakness in facioscapulohumeral muscular dystrophy (FSHD). To this aim, we evaluated quadriceps muscle and fat volumes by magnetic resonance imaging and their relationships with muscle strength and oxidative stress markers in adult patients with FSHD (n = 32) and healthy controls (n = 7), and the effect of antioxidant supplementation in 20 of the 32 patients with FSHD (n = 10 supplementation and n = 10 placebo) (NCT01596803). Compared with healthy controls, the dominant quadriceps strength and quality (muscle strength per unit of muscle volume) were decreased in patients with FSHD. In addition, fat volume was increased, without changes in total muscle volume. Moreover, in patients with FSHD, the lower strength of the non-dominant quadriceps was associated with lower muscle quality compared with the dominant muscle. Antioxidant supplementation significantly changed muscle and fat volumes in the non-dominant quadriceps, and muscle quality in the dominant quadriceps. This was associated with improved muscle strength (both quadriceps) and antioxidant response. These findings suggest that quadriceps muscle strength decline may not be simply explained by atrophy and may be influenced also by the muscle intrinsic characteristics. As FSHD is associated with increased oxidative stress, supplementation might reduce oxidative stress and increase antioxidant defenses, promoting changes in muscle function.

UPLC-MS based metabonomics revealed the protective effects of Buyang Huanwu decoction on ischemic stroke rats

Objective

Storke is a leading cause of death and disability affecting million people worldwide, 80% of which is ischemic stroke (IS). Recently, traditional Chinese medicines (TCMs) have received great attentions in treating IS due to their low poisonous effects and high safety. Buyang Huanwu Decoction (BHD), a famous and classical Chinese prescription, has been used for treating stroke-induced disability for centuries. Yet, its underlying mechanism is still in fancy.

Methods

We first constructed an IS model by middle cerebral artery occlusion (MCAO). Then, a metabonomics study on serum samples was performed using UHPLC-QTOF/MS, followed by multivariate data analysis including principal components analysis (PCA) and orthogonal partial least squares-discriminate analysis (OPLS-DA).

Results

Metabolic profiling of PCA indicated metabolic perturbation caused by MCAO was regulated by BHD back to normal levels, which is in agreement with the neurobehavioral evaluations. In the OPLS-DA, 12 metabolites were screened as potential biomarkers involved in MCAO-induced IS. Three metabolic pathways were recognized as the most relevant pathways, involving one carbon pool by folate, sphingolipid metabolism and inositol phosphate metabolism. BHD significantly reversed the abnormality of 7 metabolites to normal levels.

Conclusions

This is the first study to investigate the effect of BHD on IS at the metabolite level and to reveal the underlying mechanisms of BHD, which is complementary to neurobehavioral evaluation. In a broad sense, the current study brings novel and valuable insights to evaluate efficacy of TCMs, to interpret the action mechanisms, and to provide the theoretical basis for further research on the therapeutic mechanisms in clinical practice.

Vitamin E/Coenzyme Q-Dependent "Free Radical Reductases": Redox Regulators in Ferroptosis

Significance: Lipid peroxidation and its products, oxygenated polyunsaturated lipids, act as essential signals coordinating metabolism and physiology and can be deleterious to membranes when they accumulate in excessive amounts. Recent Advances: There is an emerging understanding that regulation of polyunsaturated fatty acid (PUFA) phospholipid peroxidation, particularly of PUFA-phosphatidylethanolamine, is important in a newly discovered type of regulated cell death, ferroptosis. Among the most recently described regulatory mechanisms is the ferroptosis suppressor protein, which controls the peroxidation process due to its ability to reduce coenzyme Q (CoQ). Critical Issues: In this study, we reviewed the most recent data in the context of the concept of free radical reductases formulated in the 1980-1990s and focused on enzymatic mechanisms of CoQ reduction in different membranes (e.g., mitochondrial, endoplasmic reticulum, and plasma membrane electron transporters) as well as TCA cycle components and cytosolic reductases capable of recycling the high antioxidant efficiency of the CoQ/vitamin E system. Future Directions: We highlight the importance of individual components of the free radical reductase network in regulating the ferroptotic program and defining the sensitivity/tolerance of cells to ferroptotic death. Complete deciphering of the interactive complexity of this system may be important for designing effective antiferroptotic modalities. Antioxid. Redox Signal. 40, 317-328.

Biological Consequences of Vanadium Effects on Formation of Reactive Oxygen Species and Lipid Peroxidation

Lipid peroxidation (LPO), a process that affects human health, can be induced by exposure to vanadium salts and compounds. LPO is often exacerbated by oxidation stress, with some forms of vanadium providing protective effects. The LPO reaction involves the oxidation of the alkene bonds, primarily in polyunsaturated fatty acids, in a chain reaction to form radical and reactive oxygen species (ROS). LPO reactions typically affect cellular membranes through direct effects on membrane structure and function as well as impacting other cellular functions due to increases in ROS. Although LPO effects on mitochondrial function have been studied in detail, other cellular components and organelles are affected. Because vanadium salts and complexes can induce ROS formation both directly and indirectly, the study of LPO arising from increased ROS should include investigations of both processes. This is made more challenging by the range of vanadium species that exist under physiological conditions and the diverse effects of these species. Thus, complex vanadium chemistry requires speciation studies of vanadium to evaluate the direct and indirect effects of the various species that are present during vanadium exposure. Undoubtedly, speciation is important in assessing how vanadium exerts effects in biological systems and is likely the underlying cause for some of the beneficial effects reported in cancerous, diabetic, neurodegenerative conditions and other diseased tissues impacted by LPO processes. Speciation of vanadium, together with investigations of ROS and LPO, should be considered in future biological studies evaluating vanadium effects on the formation of ROS and on LPO in cells, tissues, and organisms as discussed in this review.

Host-Derived Cytotoxic Agents in Chronic Inflammation and Disease Progression

At inflammatory sites, cytotoxic agents are released and generated from invading immune cells and damaged tissue cells. The further fate of the inflammation highly depends on the presence of antagonizing principles that are able to inactivate these host-derived cytotoxic agents. As long as the affected tissues are well equipped with ready-to-use protective mechanisms, no damage by cytotoxic agents occurs and resolution of inflammation is initiated. However, long-lasting and severe immune responses can be associated with the decline, exhaustion, or inactivation of selected antagonizing principles. Hence, cytotoxic agents are only partially inactivated and contribute to damage of yet-unperturbed cells. Consequently, a chronic inflammatory process results. In this vicious circle of permanent cell destruction, not only novel cytotoxic elements but also novel alarmins and antigens are liberated from affected cells. In severe cases, very low protection leads to organ failure, sepsis, and septic shock. In this review, the major classes of host-derived cytotoxic agents (reactive species, oxidized heme proteins and free heme, transition metal ions, serine proteases, matrix metalloproteases, and pro-inflammatory peptides), their corresponding protective principles, and resulting implications on the pathogenesis of diseases are highlighted.

Triangulating evidence for the causal impact of single-intervention zinc supplement on glycaemic control for type 2 diabetes: systematic review and meta-analysis of randomised controlled trial and two-sample Mendelian randomisation

Although previous studies suggested the protective effect of Zn for type 2 diabetes (T2D), the unitary causal effect remains inconclusive. We investigated the causal effect of Zn as a single intervention on glycaemic control for T2D, using a systematic review of randomised controlled trials and two-sample Mendelian randomisation (MR). Four primary outcomes were identified: fasting blood glucose/fasting glucose, HbA1c, homeostatic model assessment for insulin resistance (HOMA-IR) and serum insulin/fasting insulin level. In the systematic review, four databases were searched until June 2021. Studies, in which participants had T2D and intervention did not comprise another co-supplement, were included. Results were synthesised through the random-effects meta-analysis. In the two-sample MR, we used single-nucleotide polymorphisms (SNP) from MR-base, strongly related to Zn supplements, to infer the relationship causally, but not specified T2D. In the systematic review and meta-analysis, fourteen trials were included with overall 897 participants initially. The Zn supplement led to a significant reduction in the post-trial mean of fasting blood glucose (mean difference (MD): −26·52 mg/dl, 95 % CI (−35·13, −17·91)), HbA1c (MD: −0·52 %, 95 % CI: (−0·90, −0·13)) and HOMA-IR (MD: −1·65, 95 % CI (−2·62, −0·68)), compared to the control group. In the two-sample MR, Zn supplement with two SNP reduced the fasting glucose (inverse-variance weighted coefficient: −2·04 mmol/l, 95 % CI (−3·26, −0·83)). From the two methods, Zn supplementation alone may causally improve glycaemic control among T2D patients. The findings are limited by power from the small number of studies and SNP included in the systematic review and two-sample MR analysis, respectively.

Intrinsic and Extrinsic Limitations to the Design and Optimization of Inhibitors of Lipid Peroxidation and Associated Cell Death

The archetype inhibitors of ferroptosis, ferrostatin-1 and liproxstatin-1, were identified via high-throughput screening of compound libraries for cytoprotective activity. These compounds have been shown to inhibit ferroptosis by suppressing propagation of lipid peroxidation, the radical chain reaction that drives cell death. Herein, we present the first rational design and optimization of ferroptosis inhibitors targeting this mechanism of action. Engaging the most potent radical-trapping antioxidant (RTA) scaffold known (phenoxazine, PNX), and its less reactive chalcogen cousin (phenothiazine, PTZ), we explored structure-reactivity-potency relationships to elucidate the intrinsic and extrinsic limitations of this approach. The results delineate the roles of inherent RTA activity, H-bonding interactions with phospholipid headgroups, and lipid solubility in determining activity/potency. We show that modifications which increase inherent RTA activity beyond that of the parent compounds do not substantially improve RTA kinetics in phospholipids or potency in cells, while modifications that decrease intrinsic RTA activity lead to corresponding erosions to both. The apparent "plateau" of RTA activity in phospholipid bilayers (k_inh ∼ 2 × 10⁵ M^-1 s^-1) and cell potency (EC₅₀ ∼ 4 nM) may be the result of diffusion-controlled reactivity between the RTA and lipid-peroxyl radicals and/or the potential limitations on RTA turnover/regeneration by endogenous reductants. The metabolic stability of selected derivatives was assessed to identify a candidate for in vivo experimentation as a proof-of-concept. This PNX-derivative demonstrated stability in mouse liver microsomes comparable to liproxstatin-1 and was successfully used to suppress acute renal failure in mice brought on by tissue-specific inactivation of the ferroptosis regulator GPX4.

Ninety-day repeated oral toxicity study of saponified Capsicum annum fruit extract with 50% capsanthin in Sprague-Dawley Rats with a 28-day recovery period

A ninety-day oral toxicity study of saponified Capsicum annum fruit extract with 50% (w/w) capsanthin (SCFE-50 C) was performed by oral gavage administration to male and female Sprague-Dawley (SD) rats at doses of 0, 500, 1000 and 2000 mg/kg BW/day for a period of ninety consecutive days. To assess the reversal of toxicity, the treatment phase was followed with a twenty-eight-day recovery period. The treatment with SCFE-50 C in both male and female SD rats showed no mortality, and no treatment-related toxicologically significant changes were observed in any groups. No significant differences between treated and control groups were found in feed consumption, body weight gain, individual organ weights, ocular examination, clinical chemistry or blood biochemistry. The necroscopy and histopathology examination did not reveal any clinically significant changes in male and female rats from the 2000 mg/kg BW/day group. According to this study, the no observable adverse effect level (NOAEL) for saponified Capsicum annum fruit extract with 50% (w/w) capsanthin (SCFE-50 C) administered by oral gavage for 90-days is > 2000 mg/kg BW/day in SD rats.

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Determination of no-observed-adverse-effect-level (NOAEL) of saponified Capsicum annum fruit extract with 50% (w/w) capsanthin (SCFE-50 C).

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The no-observed-adverse-effect-level (NOAEL) of the extract of SCFE-50 C in Sprague-Dawley rats was > 2000 mg/kg BW/day.

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No histopathological changes and no treatment-related adverse effects were observed in treated and control groups.

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Capsicum annum fruit extract with 50% (w/w) capsanthin (SCFE-50 C) is safe and well tolerated.

Ergothioneine: a potential antioxidative and anti-melanosis agent for food quality preservation

The global population increase has increased the demand for food products. However, post-harvest deterioration due to oxidation and discoloration results in a drastic loss of food quality and supply. Thus, research has focused on developing strategies to minimize such losses. One of those strategies includes the application of ergothioneine (ET), a potent hydrophilic antioxidant, to several food products so as to overcome their short shelf-life. ET can be synthetic or derived from several species of edible mushrooms and their extracts, which are known sources of natural ET. Given the reported potential of ET in food quality preservation, this review compiles the recent applications of ET as a preservative for maintaining the quality of food commodities.

The Dual Role of Myeloperoxidase in Immune Response

The heme protein myeloperoxidase (MPO) is a major constituent of neutrophils. As a key mediator of the innate immune system, neutrophils are rapidly recruited to inflammatory sites, where they recognize, phagocytose, and inactivate foreign microorganisms. In the newly formed phagosomes, MPO is involved in the creation and maintenance of an alkaline milieu, which is optimal in combatting microbes. Myeloperoxidase is also a key component in neutrophil extracellular traps. These helpful properties are contrasted by the release of MPO and other neutrophil constituents from necrotic cells or as a result of frustrated phagocytosis. Although MPO is inactivated by the plasma protein ceruloplasmin, it can interact with negatively charged components of serum and the extracellular matrix. In cardiovascular diseases and many other disease scenarios, active MPO and MPO-modified targets are present in atherosclerotic lesions and other disease-specific locations. This implies an involvement of neutrophils, MPO, and other neutrophil products in pathogenesis mechanisms. This review critically reflects on the beneficial and harmful functions of MPO against the background of immune response.

Antioxidant vitamins and lysophospholipids are critical for inducing mouse spermatogenesis under organ culture conditions

In vitro mouse spermatogenesis using a classical organ culture method became possible by supplementing basal culture medium with only the product of bovine serum albumin purified by chromatography (AlbuMAX), which indicated that AlbuMAX contained every chemical factor necessary for mouse spermatogenesis. However, since the identity of these factors was unclear, improvements in culture media and our understanding of the nutritional and signal substances required for spermatogenesis were hindered. In the present study, chemically defined media (CDM) without AlbuMAX was used to evaluate each supplementary factor and their combinations for the induction of spermatogenesis. Similar to in vivo conditions, retinoic acid, triiodothyronine (T₃ ), and testosterone (T) were needed. Based on differences in spermatogenic competence between AlbuMAX, fetal bovine serum, and adult bovine serum, we identified α-tocopherol, which strongly promoted spermatogenesis when combined with ascorbic acid and glutathione. Differences were also observed in the abilities of lipids extracted from AlbuMAX using two different methods to induce spermatogenesis. This led to the identification of lysophospholipids, particularly lysophosphatidylcholine, lysophosphatidic acid, and lysophosphatidylserine, as important molecules for spermatogenesis. New CDM formulated based on these results induced and promoted spermatogenesis as efficiently as AlbuMAX-containing medium. In vitro spermatogenesis with CDM may provide a unique experimental system for research on spermatogenesis that cannot be performed in in vivo experiments.

Therapeutic effects of syringaldehyde on spinal cord ischemia in rabbits

OBJECTIVES

To investigate the effects of syringaldehyde (SA) on the antioxidant and oxidant system in spinal cord ischemia (SCI).

METHODS

These study and experiments were conducted at Medical Research Center, Çanakkale Onsekiz Mart University, Çanakkale, Turkey, between 2014-2018. Eighteen New Zealand White adult male rabbits were randomly divided into 3 groups (n=6). Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), myeloperoxidase (MPO) activities, and malondialdehyde (MDA) levels were measured in the spinal cord tissues. Degenerated neurons, hemorrhage and in ammatory cell migration in the spinal cord were investigated histopathologically. Expressions of neuronal nitric oxide synthase (nNOS), caspase-3, and nuclear factor-κB (NF-κB) were evaluated immunohistochemically. Clinically, it was evaluated with modified Tarlov score.

RESULTS

Biochemically, there was an expected decrease in SOD, CAT, and GPx enzyme activities in ischemia groups, there was also an increase in MPO activity at the same time. When the enzyme activities spinal cord ischemia/ reperfusion (SCI/R)+SA, control and SCI/R groups were compared, the difference was found to be statistically significant (p less than 0.05). Glutathione peroxidase enzyme activity levels were very low in ischemia group compared to the significant increase in the SA group (p less than 0.05). Histopathologically, when SCI/R and SCI/R+SA groups were compared, there were statistically significant differences in the number of degenerative neurons and amount of hemorrhage; this comparison shows the significance of treatment in terms of inflammatory cell migration (p less than 0.05). The expressions of nNOS, caspase-3, and NF-κB were found significantly increased in SCI/R group compared to the control group (p less than 0.05). Syringaldehyde treatment decreased nNOS, caspase-3, and NF-κB expressions immunohistochemically. Clinical evaluation showed improvement in the SA-treated group.

CONCLUSION

Syringaldehyde therapy administered for protective purposes may reduce oxidative stress, degenerative changes and in ammatory cell migration in the ischemic spinal cord.Saudi Med J 2020; Vol. 41 (4): 341-350doi: 10.15537/smj.2020.4.24993 How to cite this article:Malçok UA,  Aras AB, Şehitoğlu MH, Akman T, Yüksel Y. Therapeutic effects of syringaldehyde on spinal cord ischemia in rabbits. Saudi Med J 2020; Vol. 41: 341-350. doi: 10.15537/smj.2020.4.24993.

The effects of storage conditions on long-chain polyunsaturated fatty acids, lipid mediators, and antioxidants in donor human milk - A review

Donor human milk (DHM) is the recommended alternative, if maternal milk is unavailable. However, current human milk banking practices may negatively affect the nutritional quality of DHM. This review summarises the effects of these practices on polyunsaturated fatty acids, lipid mediators and antioxidants of human milk. Overall, there is considerable variation in the reported effects, and further research is needed, particularly with lipid mediators and antioxidants. However, to preserve nutritional quality, DHM should be protected from light exposure and storage at 4 °C minimised, to prevent decreases in vitamin C and endocannabinoids and increases in free fatty acids and lipid peroxidation products. Storage at -20 °C prior to pasteurisation should also be minimised, to prevent free fatty increases and total fat and endocannabinoid decreases. Storage ≤-70 °C is preferable wherever possible, although post-pasteurisation storage at -20 °C for three months appears safe for free fatty acids, lipid peroxidation products, and total fat content.

Utilization of Vitamin E Analogs to Protect Normal Tissues While Enhancing Antitumor Effects

Despite advances in radiation delivery techniques, side effects of radiation therapy due to radiation exposure of normal tissues are common and can limit the deliverable dose to tumors. Significant interests lie in pharmacologic modifiers that may protect against normal tissue toxicity from cancer treatment while simultaneously enhancing the tumor response to therapy. While no such treatments are available in the clinic, this is an area of active preclinical and clinical research. This review summarizes research studies that provide evidence to indicate that tocotrienols, natural forms of vitamin E, are potent radiation protectors and may also have antitumor effects. Hence, several current clinical trials test tocotrienols as concomitant treatment in cancer therapies.

Effects of vitamin C and E on toxic action of alcohol on partial hepatectomy-induced liver regeneration in rats

The purpose of this study was to investigate the influence of vitamins C and E on the toxic action of alcohol in rat liver regeneration. Male Sprague-Dawley rats subjected to 70% partial hepatectomy were divided into five groups (Groups 1 to 5). Rats in Groups 2 to 5 were only provided alcohol for drinking. Additionally, vitamin C, vitamin E, and vitamin C in combination with vitamin E were administered to Groups 3, 4, and 5, respectively. Alcohol inhibits liver regeneration, resulting in an increase in free radicals produced by alcohol metabolism and thus causing cellular damage and altering liver function. During liver regeneration, vitamins C and E significantly ameliorated liver injury from alcohol administration by reducing hepatic lipid peroxidation. Vitamins C and E protect against liver injury and dysfunction, attenuate lipid peroxidation, and thus may be more effective in combination than either vitamin alone against alcohol-mediated toxic effects during liver regeneration.

The heterozygous N291S mutation in the lipoprotein lipase gene impairs whole-body insulin sensitivity and affects a distinct set of plasma metabolites in humans

BACKGROUND

Mutations in the lipoprotein lipase gene causing decreased lipoprotein lipase activity are associated with surrogate markers of insulin resistance and the metabolic syndrome in humans.

OBJECTIVE

We investigated the hypothesis that a heterozygous lipoprotein lipase mutation (N291S) induces whole-body insulin resistance and alterations in the plasma metabolome.

METHODS

In 6 carriers of a heterozygous lipoprotein lipase mutation (N291S) and 11 age-matched and weight-matched healthy controls, we examined insulin sensitivity and substrate metabolism by euglycemic-hyperinsulinemic clamps combined with indirect calorimetry. Plasma samples were taken before and after the clamp (4 hours of physiological hyperinsulinemia), and metabolites were measured enzymatically or by gas chromatography-mass spectrometry.

RESULTS

Compared with healthy controls, heterozygous carriers of a defective lipoprotein lipase allele had elevated fasting plasma levels triglycerides (P < .006), and markedly impaired insulin-stimulated glucose disposal rates (P < .024) and nonoxidative glucose metabolism (P < .015). Plasma metabolite profiling demonstrated lower circulating levels of pyruvic acid and α-tocopherol in the N291S carriers than in controls both before and after stimulation with insulin (all >1.5-fold change and P < .05).

CONCLUSION

Heterozygous carriers with a defective lipoprotein lipase allele are less insulin sensitive and have increased plasma levels of nonesterified fatty acids and triglycerides. The heterozygous N291S carriers also have a distinct plasma metabolomic signature, which may serve as a diagnostic tool for deficient lipoprotein lipase activity and as a marker of lipid-induced insulin resistance.

Perinatal hypothyroidism modulates antioxidant defence status in the developing rat liver and heart

In the present study, we investigated oxidative stress parameters and antioxidant defence status in perinatal hypothyroid rat liver and heart. We found that the proteincarbonyl content did not differ significantly between the three groups both in the pup liver and in the heart. The OH˙ level was significantly decreased in the hypothyroid heart but not in the liver compared with controls. A slight but not significant decrease in SOD activity was observed in both perinatal hypothyroid liver and heart. A significantly increased activity of CAT was observed in the liver but not in the heart of hypothyroid pups. The GPx activity was considerably increased compared with controls in the perinatal hypothyroid heart and was unaltered in the liver of hypothyroid pups. We also found that vitamin E levels in the liver decreased significantly in hypothyroidism and were unaltered in the heart of perinatal hypothyroid rats. The GSH content was elevated significantly in both hypothyroid liver and heart. The total antioxidant capacity was higher in the liver of the hypothyroid group but not in the hypothyroid heart. Thyroxine replacement could not repair the above changes to normal. In conclusion, perinatal hypothyroidism modulates the oxidative stress status of the perinatal liver and heart.

Effects of Ganoderma lucidum polysaccharides on chronic pancreatitis and intestinal microbiota in mice

This study manifested the effects of polysaccharides from Ganoderma lucidum strain S₃ (GLP S₃) on chronic pancreatitis (CP) therapy and intestinal microbiota modulation in mice induced by diethyldithiocarbamate (DDC). The GLPS₃ was prepared from cultured mycelium and markedly alleviated the pancreatitis in mice through decreasing lipase, AMS, IFN-γ and TNF-α level as well as increasing SOD and total antioxidant activity. Furthermore, high throughput sequencing analysis revealed that GLPS₃ altered the composition and diversity of intestinal microbiota, especially, decreased the relative abundance of phylum Bacteroidetes and increased that of phylum Firmictutes. At the genus level, supplementation of GLPS₃ increased the relative abundance of the beneficial bacteria such as Lactobacillales, Roseburia and Lachnospiraceae. These results disclosed the potential therapy mechanism of GLPS₃ on chronic pancreatitis might be intestinal microbiota dependent.

Impact of Antioxidants on Cardiolipin Oxidation in Liposomes: Why Mitochondrial Cardiolipin Serves as an Apoptotic Signal?

Molecules of mitochondrial cardiolipin (CL) get selectively oxidized upon oxidative stress, which triggers the intrinsic apoptotic pathway. In a chemical model most closely resembling the mitochondrial membrane-liposomes of pure bovine heart CL-we compared ubiquinol-10, ubiquinol-6, and alpha-tocopherol, the most widespread naturally occurring antioxidants, with man-made, quinol-based amphiphilic antioxidants. Lipid peroxidation was induced by addition of an azo initiator in the absence and presence of diverse antioxidants, respectively. The kinetics of CL oxidation was monitored via formation of conjugated dienes at 234 nm. We found that natural ubiquinols and ubiquinol-based amphiphilic antioxidants were equally efficient in protecting CL liposomes from peroxidation; the chromanol-based antioxidants, including alpha-tocopherol, were 2-3 times less efficient. Amphiphilic antioxidants, but not natural ubiquinols and alpha-tocopherol, were able, additionally, to protect the CL bilayer from oxidation by acting from the water phase. We suggest that the previously reported therapeutic efficiency of mitochondrially targeted amphiphilic antioxidants is owing to their ability to protect those CL molecules that are inaccessible to natural hydrophobic antioxidants, being trapped within respiratory supercomplexes. The high susceptibility of such occluded CL molecules to oxidation may have prompted their recruitment as apoptotic signaling molecules by nature.

Hyperbilirubinemia exaggerates endotoxin-induced hypothermia

Systemic inflammation is accompanied by an increased production of reactive oxygen species (ROS) and by either fever or hypothermia (or both). To study aseptic systemic inflammation, it is often induced in rats by the intravenous administration of bacterial lipopolysaccharide (LPS). Knowing that bilirubin is a potent ROS scavenger, we compared responses to LPS between normobilirubinemic Gunn rats (heterozygous, asymptomatic; J/+) and hyperbilirubinemic Gunn rats (homozygous, jaundiced; J/J) to establish whether ROS mediate fever and hypothermia in aseptic systemic inflammation. These two genotypes correspond to undisturbed versus drastically suppressed (by bilirubin) tissue accumulation of ROS, respectively. A low dose of LPS (10 μg/kg) caused a typical triphasic fever in both genotypes, without any intergenotype differences. A high dose of LPS (1,000 μg/kg) caused a complex response consisting of early hypothermia followed by late fever. The hypothermic response was markedly exaggerated, whereas the subsequent fever response was strongly attenuated in J/J rats, as compared to J/+ rats. J/J rats also tended to respond to 1,000 μg/kg with blunted surges in plasma levels of all hepatic enzymes studied (alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase), thus suggesting an attenuation of hepatic damage. We propose that the reported exaggeration of LPS-induced hypothermia in J/J rats occurs via direct inhibition of nonshivering thermogenesis by bilirubin and possibly via a direct vasodilatatory action of bilirubin in the skin. This hypothermia-exaggerating effect might be responsible, at least in part, for the observed tendency of J/J rats to be protected from LPS-induced hepatic damage. The attenuation of the fever response to 1,000 μg/kg could be due to either direct actions of bilirubin on thermoeffectors or the ROS-scavenging action of bilirubin. However, the experiments with 10 μg/kg strongly suggest that ROS signaling is not involved in the fever response to low doses of LPS.

Effects of Copper, Zinc, and Vitamin Complex (Cernevit®) on Hepatic Healing in Rats Experimentally Subjected to Blunt Hepatic Trauma

Solid organ injuries following blunt trauma are frequently encountered. The use of non-operative approach is gradually increasing. Thus, research on the methods that could enhance healing in solid organ injuries is in progress. Agents known to have antioxidant property were used after an experimentally induced blunt hepatic trauma. Thirty-two Wistar albino rats weighing 200 g were dropped from a height of 40 cm on to the right upper abdominal quadrant to produce a grade II-III hepatic injury. Rats were divided into control, Zn-administered, Cu-administered, and vitamin complex-administered groups, with eight rats in each. Aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) levels were measured in the blood samples. The percentage of cells displaying Ki-67 nuclear staining was estimated. The sections were stained with hematoxylin and eosin and the degree of inflammation in the samples was semi-quantitatively assessed. Treatment with zinc, copper, and Cernevit® caused varying levels of decrease in AST, ALT, and LDH levels compared to the control group. Ki-67 positivity was significantly lower in group I compared with groups II and III (p = 0.002). Ki-67 positivity was significantly higher in group II compared to the other groups (p < 0.05). A marked improvement was observed in inflammation in group II. Copper and zinc treatment decreased inflammation as well as blood levels of AST and ALT, and enhanced the healing of traumatized hepatic tissue. However, Cernevit® reduced only the degree of inflammation.

Androgen deficiency and mitochondrial dysfunction: implications for fatigue, muscle dysfunction, insulin resistance, diabetes, and cardiovascular disease

Among the major physiological functions of steroid hormones is regulation of carbohydrate, fat, and protein metabolism. Mitochondria, through oxidative phosphorylation, play a critical role in modulating a host of complex cellular metabolic pathways to produce chemical energy to meet the metabolic demand for cellular function. Thus, androgens may regulate cellular metabolism and energy production by increased mitochondrial numbers, activation of respiratory chain components, and increased transcription of mitochondrial-encoded respiratory chain genes that code for enzymes responsible for oxidative phosphorylation. Androgen deficiency is associated with increased insulin resistance, type 2 diabetes (T2DM), metabolic syndrome, obesity, and increased overall mortality. One common link among all these pathologies is mitochondrial dysfunction. Contemporary evidence exists suggesting that testosterone deficiency (TD) contributes to mitochondrial dysfunction, including structural alterations and reduced expression and activities of metabolic enzymes. Here, we postulate that TD contributes to symptoms of fatigue, insulin resistance, T2DM, cardiovascular risk, and metabolic syndrome through a common mechanism involving impairment of mitochondrial function.

Methods for determining the efficacy of radical-trapping antioxidants

Hydrocarbon autoxidation is the free radical chain reaction primarily responsible for the oxidative degradation of organic materials, including those that make up cells, tissues, and organs. The identification of compounds that slow this process (antioxidants) and the quantitation of their efficacies have long been goals of academic and industrial researchers. Antioxidants are generally divided into two types: preventive and radical-trapping (also commonly referred to as chain-breaking). Preventive antioxidants slow the rate of initiation of autoxidation, whereas radical-trapping antioxidants slow the rate of propagation by reacting with chain-propagating peroxyl radicals. The purpose of this review is to provide a comprehensive overview of different approaches to measure the kinetics of the reactions of radical-trapping antioxidants with peroxyl radicals, and their use to study the inhibition of hydrocarbon (lipid) autoxidation in homogeneous solution, as well as biphasic media (lipid bilayers) and cell culture. Direct and indirect approaches are presented and advantages and disadvantages of each are discussed in order to facilitate method selection for investigators seeking to address particular questions in this immensely popular field.

Effects of vitamin C, vitamin E, zinc gluconate, and selenomethionine supplementation on muscle function and oxidative stress biomarkers in patients with facioscapulohumeral dystrophy: a double-blind randomized controlled clinical trial

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant disease characterized by progressive weakness and atrophy of specific skeletal muscles. As growing evidence suggests that oxidative stress may contribute to FSHD pathology, antioxidants that might modulate or delay oxidative insults could help in maintaining FSHD muscle function. Our primary objective was to test whether oral administration of vitamin C, vitamin E, zinc gluconate, and selenomethionine could improve the physical performance of patients with FSHD. Adult patients with FSHD (n=53) were enrolled at Montpellier University Hospital (France) in a randomized, double-blind, placebo-controlled pilot clinical trial. Patients were randomly assigned to receive 500 mg vitamin C, 400mg vitamin E, 25mg zinc gluconate and 200 μg selenomethionine (n=26), or matching placebo (n=27) once a day for 17 weeks. Primary outcomes were changes in the two-minute walking test (2-MWT), maximal voluntary contraction, and endurance limit time of the dominant and nondominant quadriceps (MVCQD, MVCQND, TlimQD, and TlimQND, respectively) after 17 weeks of treatment. Secondary outcomes were changes in the antioxidant status and oxidative stress markers. Although 2-MWT, MVCQ, and TlimQ were all significantly improved in the supplemented group at the end of the treatment compared to baseline, only MVCQ and TlimQ variations were significantly different between groups (MVCQD: P=0.011; MVCQND: P=0.004; TlimQD: P=0.028; TlimQND: P=0.011). Similarly, the vitamin C (P<0.001), vitamin E as α-tocopherol (P<0.001), vitamin C/vitamin E ratio (P=0.017), vitamin E γ/α ratio (P=0.022) and lipid peroxides (P<0.001) variations were significantly different between groups. In conclusion, vitamin E, vitamin C, zinc, and selenium supplementation has no significant effect on the 2-MWT, but improves MVCQ and TlimQ of both quadriceps by enhancing the antioxidant defenses and reducing oxidative stress. This trial was registered at clinicaltrials.gov (number: NCT01596803).

Phenolic production and antioxidant properties of some Macedonian medicinal plants

Investigations have been made to study the production of phenolic compounds (total phenolics, flavonoids and phenylpropanoids) and total antioxidant capacity in 27 Macedonian traditional medicinal plants to improve its potential as a source of natural antioxidants. Antioxidant potential of plant extracts was analyzed by five different assays: cupric reducing antioxidant capacity (CUPRAC), phosphomolybdenum method (PM), reducing power (RP), 2,2-diphenyl-1-picrylhydrazyl (DPPH·) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS·+) radical scavenging activity. Origanum vulgare extract consistently exhibited the highest content of phenolic compounds and the strongest antioxidant capacity based on the tests performed, and can be proposed as a promising source of natural antioxidants. Melissa officinalis and Salvia ringens were also identified as valuable sources of antioxidant compounds. A positive linear correlation between antioxidant activity and total phenolics, flavonoids and phenylpropanoids indicates that these compounds are likely to be the main antioxidants contributing to the observed activities of evaluated plants. These findings suggest that the medicinal plants studied in this paper are good sources of bioactive compounds for the food and pharmaceutical industries.

A time-dose model to quantify the antioxidant responses of the oxidative hemolysis inhibition assay (OxHLIA) and its extension to evaluate other hemolytic effectors

The development of a convenient mathematical application for testing the antioxidant potential of standard and novel therapeutic agents is essential for the research community to perform evaluations in a more precise form. The in vitro oxidative hemolysis inhibition assay, despite its relevance for in vivo responses, lacks a proper mathematical model to quantify the responses. In this work, a simple nonlinear time-dose tool to test the effectiveness of antioxidant compounds is presented. The model was verified with available experimental data from the bibliography. The model helps to describe accurately the antioxidant response as a function of time and dose allowing comparisons between compounds. Its advantages are a simple application, provision of parametric estimates that characterize the response, simplification of the protocol, economization of experimental effort, and facilitation of rigorous comparisons among the effects of different compounds and experimental approaches. Finally, other effectors that may obstruct or be of interest for the antioxidant determination are also modeled in similar principles. Thus, the basis of more complex multivariable models is provided. In all experimental data fitted, the calculated parameters were always statistically significant, the equations prove to be consistent, and the correlation coefficient of determination was in all cases higher than 0.98.

Ultrasound-assisted synthesis of novel 1,2,3-triazoles coupled diaryl sulfone moieties by the CuAAC reaction, and biological evaluation of them as antioxidant and antimicrobial agents

A series of 1,2,3-triazoles coupled diaryl sulfone containing compounds were synthesized by the copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) reaction in benign solvents under ultrasound irradiation. In situ formation of azides from α-bromoketones together with the CuAAC reaction in one pot allowed safe handling and good availability of azides for the development of a small library of compounds. The sonication reduced reaction time and increased yields compared to otherwise same conditions. All synthesized compounds were evaluated for antibacterial, antifungal and antioxidant activities. Compounds 3b, 6b and 9e-9g were found to be the most potent antifungal agents with minimal inhibitory concentration (MIC) at 25 μg/mL; moreover other compounds revealed good to moderate antimicrobial activity. Compound 8e showed an excellent antioxidant activity using a DPPH free radical scavenging assay.

Nonallergenic urushiol derivatives inhibit the oxidation of unilamellar vesicles and of rat plasma induced by various radical generators

Urushiols consist of an o-dihydroxybenzene (catechol) structure and an alkyl chain of 15 or 17 carbons in the 3-position of a benzene ring and are allergens found in the family Anacardiaceae. We synthesized various veratrole (1,2-dimethoxybenzene)-type and catechol-type urushiol derivatives that contained alkyl chains of various carbon atom lengths, including -H, -C1H3, -C5H11, -C10H21, -C15H31, and -C20H41, and investigated their contact hypersensitivities and antioxidative activities. 3-Decylcatechol and 3-pentadecylcatechol displayed contact hypersensitivity, but the other compounds did not induce an allergic reaction, when the ears of rats were sensitized by treatment with the compounds every day for 20 days. Catechol-type urushiol derivatives (CTUDs) exerted very high radical-scavenging activity on the 1,1-diphenyl-2-picrylhydrazyl radical and inhibited lipid peroxidation in a methyl linoleate solution induced by 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN). However, veratrole-type urushiol derivatives did not scavenge or inhibit lipid peroxidation. CTUDs also acted as effective inhibitors of lipid peroxidation of the egg yolk phosphatidylcholine large unilamellar vesicle (PC LUV) liposome system induced by various radical generators such as AMVN, 2,2'-azobis(2-amidino-propane) dihydrochloride, and copper ions, although their efficiencies differed slightly. In addition, CTUDs suppressed formation of cholesteryl ester hydroperoxides in rat blood plasma induced with copper ions. CTUDs containing more than five carbon atoms in the alkyl chain showed excellent lipophilicity in a n-octanol/water partition experiment. These compounds also exhibited high affinities to the liposome membrane using the ultrafiltration method of the PC LUV liposome system. Therefore, CTUDs seem to act as efficient antioxidative compounds against membranous lipid peroxidation owing to their localization in the phospholipid bilayer. These results suggest that nonallergenic CTUDs act as antioxidants to protect against oxidative damage of cellular and subcellular membranes.

Membrane lipid oxidation and proteolytic activity in thigh muscles from broilers fed different diets

The effects of diets differing in their level of unsaturation and their contents of natural antioxidants and prooxidants on lipid oxidation was measured in microsomal membranes of the thigh muscles of broilers by three processes: enzymatic, nonenzymatic and sarcoplasmic protein oxidation. Lysosomal cysteine proteinase activities were determined to assess the influence of the different diets on the enzymatic proteolysis of meat. Statistically significant differences were found in the enzymatic reaction for 72 h of incubation at 4°C in relation to the effect of both diet and antioxidant supplementation. Meat from animals fed an unsaturated diet containing sunflower oil gave the highest level of oxidation. Broilers fed supplemental antioxidants, especially α-tocopherol, had lower degrees of oxidation than those fed the basal diet. An unexpected result of the prooxidant diet study was a higher degree of oxidation in samples from animals deprived of iron and copper. Cysteine proteinase activities were favoured by vitamin E (α-tocopherol) supplementation and the absence of copper. ©

Protection of astaxanthin in astaxanthin nanodispersions using additional antioxidants

The protective effects of α-tocopherol and ascorbic acid on astaxanthin in astaxanthin nanodispersions produced via a solvent-diffusion technique and stabilized by a three-component stabilizer system, were studied either individually or in combination by using response surface methodology. Generally, both α-tocopherol and ascorbic acid could retard the astaxanthin degradation in astaxanthin nanodispersions. The results showed that the using α-tocopherol and ascorbic acid can be more efficient in increasing the chemical stability of nanodispersions in comparison to using them individually. Using a response surface methodology (RSM) response optimizer, it was seen that addition of ascorbic acid (ascorbic acid/astaxanthin w/w) and α-tocopherol (α-tocopherol/astaxanthin w/w) in proportions of 0.4 and 0.6, respectively, would give the maximum chemical stability to the studied astaxanthin nanodispersions.

Assessment of phytochemicals, antioxidant, anti-lipid peroxidation and anti-hemolytic activity of extract and various fractions of Maytenus royleanus leaves

BACKGROUND

Maytenus royleanus is traditionally used in gastro-intestinal disorders. The aim of this study was to evaluate the methanol extract of leaves and its derived fractions for various antioxidant assays and for its potential against lipid peroxidation and hemolytic activity.

METHODS

Various parameters including scavenging of free-radicals (DPPH, ABTS, hydroxyl and superoxide radical), hydrogen peroxide scavenging, Fe3+ to Fe2+ reducing capacity, total antioxidant capacity, anti-lipid peroxidation and anti-hemolytic activity were investigated. Methanol extract and its derived fractions were also subjected for chemical constituents. LC-MS was also performed on the methanol extract.

RESULTS

Qualitative analysis of methanol extract exhibited the presence of alkaloids, anthraquinones, cardiac glycosides, coumarins, flavonoids, saponins, phlobatannins, tannins and terpenoids. LC-MS chromatogram indicated the composition of diverse compounds including flavonoids, phenolics and phytoestrogens. Methanol extract, its ethyl acetate and n-butanol fractions constituted the highest amount of total phenolic and flavonoid contents and showed a strong correlation coefficient with the IC50 values for the scavenging of DPPH, hydrogen peroxide radicals, superoxide radicals, anti-lipid peroxidation and anti-hemolytic efficacy. Moreover, n-butanol fraction showed the highest scavenging activity for ABTS radicals and for reduction of Fe3+ to Fe2+.

CONCLUSIONS

Present results suggested the therapeutic potential of Maytenus royleanus leaves, in particular, methanol extract, ethyl acetate and n-butanol fraction as therapeutic agent against free-radical associated damages. The protective potential of the extract and or fraction may be attributed due to the high concentration of phenolic, flavonoid, tannins and terpenoids.

Activation of platelets upon contact with a vitamin E-coated/non-coated surface

The purpose of this study was to determine the effects of a vitamin E-coated surface on platelet activation, focusing on the interactions among the vitamin E-coated surface, platelets and leukocytes. Platelet-rich plasma (PRP) or PRP containing leukocytes (LPRP) was used. No difference was observed in platelet activation between PRP and LPRP for a vitamin E-coated membrane, meaning that platelet activation triggered by leukocytes was suppressed in plasma coming in contact with a vitamin E-coated membrane, while the membrane itself directly induced platelet activation. The antioxidant capacity of the vitamin E-coated membrane in contact with PRP or LPRP was partially reduced, but sufficient residual capacity remained. The in vitro experiments using an oxidized vitamin E-coated surface revealed that P-selectin expression and superoxide anion production in the platelets and platelet adhesion were induced by contact with the oxidized vitamin E-coated surface. We conclude that contact with a vitamin E-coated surface reduces platelet activation mediated by superoxide anions, probably by reducing superoxide anions, but during the process of the reduction, the vitamin E-coated surface itself becomes oxidized, which again causes platelet activation. The beneficial effects of a vitamin E-coated dialyzer in respect of platelet activation were counteracted by the formation of oxidized vitamin E.