Free radical-mediated damage of blood and its inhibition by antioxidants

Copper(ii) complexes with terpene derivatives of ethylenediamine: synthesis, and antibacterial, antifungal and antioxidant activity

The synthesis of new chiral copper(ii) complexes with terpene derivatives of ethylenediamine and the results of studying their antibacterial, antifungal and antioxidant activity in vitro are discussed. All studied copper complexes (1-4) showed significantly higher antifungal activity against the strains of C. albicans, S. salmonicolor and P. notatum compared to the activity of the clinical antifungal drug amphotericin. High antibacterial activity of copper complexes with terpene derivatives of ethylenediamine was revealed against the S. aureus (MRSA) strain, which is resistant to the reference antibiotic ciprofloxacin. Using various test systems, a comparative assessment of the antioxidant activity (AOA) of the synthesized copper complexes and the ligands was carried out. The salen-type complex 4, which has the highest AOA in the model of initiated oxidation of a substrate containing animal lipids, was superior to other copper complexes in the ability to protect erythrocytes under conditions of H2O2-induced hemolysis.

Measurement of Redox Biomarkers in the Whole Blood and Red Blood Cell Lysates of Dogs

The evaluation of the biomarkers of oxidative status is usually performed in serum, however, other samples, such as red blood cells (RBCs) lysates or whole blood (WB), can be used. The objective of this study was to evaluate if a comprehensive panel of redox biomarkers can be measured in the WB and RBCs of dogs, and their possible changes “in vitro” after the addition of different concentrations of ascorbic acid. The panel was integrated by biomarkers of the antioxidant status, such as cupric reducing antioxidant capacity (CUPRAC), ferric reducing ability of plasma (FRAP), Trolox equivalent antioxidant capacity (TEAC), thiol and paraoxonase type 1 (PON-1), and of the oxidant status, such as total oxidant status (TOS), peroxide-activity (POX-Act), reactive oxygen-derived compounds (d-ROMs), advanced oxidation protein products (AOPP) and thiobarbituric acid reactive substances (TBARS). All the assays were precise and accurate in WB and RBCs lysates. In addition, they showed changes after ascorbic acid addition that are in line with previously published results, being WB more sensitive to detect these changes in our experimental conditions. In conclusion, the panel of assays used in this study can be measured in the WB and RBCs of the dog. In particular, the higher sensitivity to detect changes in our experimental conditions and its easier sample preparation makes WB a promising sample for the evaluation of redox status in dogs, with also potential applications to other animal species and humans.

Lipid oxidation that is, and is not, inhibited by vitamin E: Consideration about physiological functions of vitamin E

Lipids are oxidized in vivo by multiple oxidizing species with different properties, some by regulated manner to produce physiological mediators, while others by random mechanisms to give detrimental products. Vitamin E plays an important role as a physiologically essential antioxidant to inhibit unregulated lipid peroxidation by scavenging lipid peroxyl radicals to break chain propagation independent of the type of free radicals which induce chain initiation. Kinetic data suggest that vitamin E does not act as an efficient scavenger of nitrogen dioxide radical, carbonate anion radical, and hypochlorite. The analysis of regio- and stereo-isomer distribution of the lipid oxidation products shows that, apart from lipid oxidation by CYP enzymes, the free radical-mediated lipid peroxidation is the major pathway of lipid oxidation taking place in humans. Compared with healthy subjects, the levels of racemic and trans,trans-hydro (pero)xyoctadecadienoates, specific biomarker of free radical lipid oxidation, are elevated in the plasma of patients including atherosclerosis and non-alcoholic fatty liver diseases. α-Tocopherol acts as a major antioxidant, while γ-tocopherol scavenges nitrogen dioxide radical, which induces lipid peroxidation, nitration of aromatic compounds and unsaturated fatty acids, and isomerization of cis-fatty acids to trans-fatty acids. It is essential to appreciate that the antioxidant effects of vitamin E depend on the nature of both oxidants and substrates being oxidized. Vitamin E, together with other antioxidants such as vitamin C, contributes to the inhibition of detrimental oxidation of biological molecules and thereby to the maintenance of human health and prevention of diseases.

Natural Antioxidant Anthocyanins-A Hidden Therapeutic Candidate in Metabolic Disorders with Major Focus in Neurodegeneration

All over the world, metabolic syndrome constitutes severe health problems. Multiple factors have been reported in the pathogenesis of metabolic syndrome. Metabolic disorders result in reactive oxygen species (ROS) induced oxidative stress, playing a vital role in the development and pathogenesis of major health issues, including neurological disorders Alzheimer's disease (AD) Parkinson's disease (PD). Considerable increasing evidence indicates the substantial contribution of ROS-induced oxidative stress in neurodegenerative diseases. An imbalanced metabolism results in a defective antioxidant defense system, free radicals causing inflammation, cellular apoptosis, and tissue damage. Due to the annual increase in financial and social burdens, in addition to the adverse effects associated with available synthetic agents, treatment diversion from synthetic to natural approaches has occurred. Antioxidants are now being considered as convincing therapeutic agents against various neurodegenerative disorders. Therefore, medicinal herbs and fruits currently receive substantially more attention as commercial sources of antioxidants. In this review, we argue that ROS-targeted therapeutic interventions with naturally occurring antioxidant flavonoid, anthocyanin, and anthocyanin-loaded nanoparticles might be the ultimate treatment against devastating illnesses. Furthermore, we elucidate the hidden potential of the neuroprotective role of anthocyanins and anthocyanin-loaded nanoparticles in AD and PD neuropathies, which lack sufficient attention compared with other polyphenols, despite their strong antioxidant potential. Moreover, we address the need for future research studies of native anthocyanins and nano-based-anthocyanins, which will be helpful in developing anthocyanin treatments as therapeutic mitochondrial antioxidant drug-like regimens to delay or prevent the progression of neurodegenerative diseases, such as AD and PD.

The physiopathologic role of oxidative stress in skeletal muscle

Muscle senescence is a complex mechanism that is usually associated with a decrease in mass, strength and velocity of contraction. This state, known as sarcopenia, is a multifactorial process and it may be the consequence of several events, including accumulation of oxidative stress. The role of oxidative stress in the physiopathology of skeletal muscle is quite complex. Transiently increased levels of oxidative stress might reflect a potentially health promoting process, while an uncontrolled accumulation might have pathological implication. The physiopathological role of oxidative stress on skeletal muscle, its involvement in aging-induced sarcopenia, and potential countermeasures will be discussed.

Antioxidant capacity of foods for scavenging reactive oxidants and inhibition of plasma lipid oxidation induced by multiple oxidants

Unregulated oxidation of biological molecules induced by multiple oxidants has been implicated in the pathogenesis of various diseases. Consequently, the effects of antioxidants contained in foods, beverages and supplements on the maintenance of health and prevention of diseases have attracted much attention of the public as well as scientists. However, recent human studies have shown inconsistent results and failed to demonstrate the beneficial effects of antioxidants. The mechanisms and dynamics of antioxidant action and assessment of antioxidant capacity have been the subject of extensive studies and arguments. In the present article, the antioxidant capacity has been reviewed focusing on two main issues: the capacity of antioxidants to scavenge multiple reactive oxidants and to inhibit plasma lipid oxidation induced by different biological oxidants. It is emphasized that the capacity of antioxidants to scavenge reactive oxidants does not always correlate linearly with the capacity to inhibit lipid oxidation and that it is necessary to specify the oxidant to assess the efficacy of antioxidants, since multiple oxidants contribute to oxidative damage in vivo and the effects of antioxidants depend on the nature of oxidants. A convenient and rapid method using a microplate reader is discussed for assessing the antioxidant capacity against plasma lipid oxidation induced by multiple oxidants including peroxyl radicals, peroxynitrite, hypochlorite, 15-lipoxygenase, and singlet oxygen.

New Zealand blackcurrant extract improves cycling performance and fat oxidation in cyclists

PURPOSE

Blackcurrant intake increases peripheral blood flow in humans, potentially by anthocyanin-induced vasodilation which may affect substrate delivery and exercise performance. We examined the effects of New Zealand blackcurrant (NZBC) extract on substrate oxidation, cycling time-trial performance and plasma lactate responses following the time-trial in trained cyclists.

METHODS

Using a randomized, double-blind, crossover design, 14 healthy men (age: 38 ± 13 years, height: 178 ± 4 cm, body mass: 77 ± 9 kg, VO2max: 53 ± 6 mL kg(-1) min(-1), mean ± SD) ingested NZBC extract (300 mg day(-1) CurraNZ™ containing 105 mg anthocyanin) or placebo (PL, 300 mg microcrystalline cellulose M102) for 7 days (washout 14 days). On day 7, participants performed 30 min of cycling (3 × 10 min at 45, 55 and 65 % VO2max), followed by a 16.1 km time-trial with lactate sampling during a 20-min passive recovery.

RESULTS

NZBC extract increased fat oxidation at 65 % VO2max by 27 % (P < 0.05) and improved 16.1 km time-trial performance by 2.4 % (NZBC: 1678 ± 108 s, PL: 1722 ± 131 s, P < 0.05). Plasma lactate was higher with NZBC extract immediately following the time-trial (NZBC: 7.06 ± 1.73 mmol L(-1), PL: 5.92 ± 1.58 mmol L(-1), P < 0.01).

CONCLUSIONS

Seven-day intake of New Zealand blackcurrant extract improves 16.1 km cycling time-trial performance and increases fat oxidation during moderate intensity cycling.

Multi-Component Profiling of Trace Volatiles in Blood by Gas Chromatography/Mass Spectrometry with Dynamic Headspace Extraction

A dynamic headspace extraction method (DHS) with high-pressure injection is described. This dynamic extraction method has superior sensitivity to solid phase micro extraction, SPME and is capable of extracting the entire gas phase by purging the headspace of a vial. Optimization of the DHS parameters resulted in a highly sensitive volatile profiling system with the ability to detect various volatile components including alcohols at nanogram levels. The average LOD for a standard volatile mixture was 0.50 ng mL(-1), and the average LOD for alcohols was 0.66 ng mL(-1). This method was used for the analysis of volatile components from biological samples and compared with acute and chronic inflammation models. The method permitted the identification of volatiles with the same profile pattern as in vitro oxidized lipid-derived volatiles. In addition, the concentration of alcohols and aldehydes from the acute inflammation model samples were significantly higher than that for the chronic inflammation model samples. The different profiles between these samples could also be identified by this method. Finally, it was possible to analyze alcohols and low-molecular-weight volatiles that are difficult to analyze by SPME in high sensitivity and to show volatile profiling based on multi-volatile simultaneous analysis.

Association of vegetables and fruits consumption with sarcopenia in older adults: the Fourth Korea National Health and Nutrition Examination Survey

BACKGROUND

several studies have found nutrients, including antioxidants, to be associated with sarcopenia. However, whether specific foods, such as vegetables and fruits, are associated with sarcopenia has not been studied.

OBJECTIVE

to examine the association of the frequency of vegetables and fruits consumption with sarcopenia in older people.

METHODS

this study used cross-sectional data from the Fourth Korea National Health and Nutrition Examination Survey in 2008-09. Subjects were community-dwelling 823 men and 1,089 women aged ≥65 years. Frequency of food group consumption was obtained by using the food frequency questionnaire. Body composition was measured with the dual-energy X-ray absorptiometry and sarcopenia was defined as appendicular lean mass adjusted for height and fat mass. Logistic regression was used to assess the association of the frequency of food group consumption with sarcopenia, controlling for sociodemographics and health-related variables.

RESULTS

dietary intake of vegetables, fruits and both vegetables and fruits was associated with a significantly reduced risk of sarcopenia after controlling for covariates in men (P = 0.026 for trend, P = 0.012 for trend, P = 0.003 for trend, respectively). Men in the highest quintile, compared with those in the lowest quintile, of vegetables [odds ratio (OR) = 0.48; 95% confidence interval (CI): 0.24-0.95], fruits (OR = 0.30; 95% CI: 0.13-0.70) and vegetables and fruits consumption (OR = 0.32; 95% CI: 0.16-0.67) demonstrated a lower risk of sarcopenia. In women, high consumption of fruits demonstrated a lower risk of sarcopenia (OR = 0.39; 95% CI: 0.18-0.83).

CONCLUSION

frequent vegetables and fruits consumption was inversely associated with sarcopenia in older adults.

Role of vitamin E as a lipid-soluble peroxyl radical scavenger: in vitro and in vivo evidence

Multiple reactive oxygen/nitrogen species induce oxidative stress. Mammals have evolved with an elaborate defense network against oxidative stress, in which multiple antioxidant compounds and enzymes with different functions exert their respective roles. Radical scavenging is one of the essential roles of antioxidants and vitamin E is the most abundant and important lipophilic radical-scavenging antioxidant in vivo. The kinetic data and physiological molar ratio of vitamin E to substrates show that the peroxyl radicals are the only radicals that vitamin E can scavenge to break chain propagation efficiently and that vitamin E is unable to act as a potent scavenger of hydroxyl, alkoxyl, nitrogen dioxide, and thiyl radicals in vivo. The preventive effect of vitamin E against the oxidation mediated by nonradical oxidants such as hypochlorite, singlet oxygen, ozone, and enzymes may be limited in vivo. The synergistic interaction of vitamin E and vitamin C is effective for enhancing the antioxidant capacity of vitamin E. The in vitro and in vivo evidence of the function of vitamin E as a peroxyl radical-scavenging antioxidant and inhibitor of lipid peroxidation is presented.

Comparison of the inhibitory effect against copper ion-induced oxidation in rat plasma after oral administration of salvianolic acid B and its decocted solutions

The effects of salvianolic acid B (Sal B) decoction on antioxidative activities were evaluated. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity, Fe(2+)-chelating activity, reducing power, and total phenolic content of the Sal B-decocted solutions did not change significantly after decoction in an aqueous solution. However, the formation of cholesteryl ester hydroperoxide (CE-OOH) in rat blood plasma containing the Sal B-decocted solutions was more effectively inhibited than that of plasma containing the Sal B solution, regardless of the decoction time. In addition, the accumulation of CE-OOH in rat plasma after oral administration of the Sal B-decocted solutions was more effectively suppressed than when the Sal B solution was administered, considering the lag time. It is likely that the decoction was partly responsible for the increased antioxidant activity in blood plasma. Therefore, the Sal B-decocted solution may contribute more to antioxidant defense in blood than a Sal B solution that is not decocted.

Relationship between human aging muscle and oxidative system pathway

Ageing is a complex process that in muscle is usually associated with a decrease in mass, strength, and velocity of contraction. One of the most striking effects of ageing on muscle is known as sarcopenia. This inevitable biological process is characterized by a general decline in the physiological and biochemical functions of the major systems. At the cellular level, aging is caused by a progressive decline in mitochondrial function that results in the accumulation of reactive oxygen species (ROS) generated by the addition of a single electron to the oxygen molecule. The aging process is characterized by an imbalance between an increase in the production of reactive oxygen species in the organism and the antioxidant defences as a whole. The goal of this review is to examine the results of existing studies on oxidative stress in aging human skeletal muscles, taking into account different physiological factors (sex, fibre composition, muscle type, and function).

Assessment of antioxidant capacity for scavenging free radicals in vitro: a rational basis and practical application

With increasing evidence showing the involvement of oxidative stress induced by free radicals in the development of various diseases, the role of radical-scavenging antioxidants has received much attention. Although many randomized controlled clinical trials do not support the beneficial effects of indiscriminate supplementation of antioxidants, more recent studies suggest that antioxidants such as vitamin E may be effective for prevention and treatment of some diseases when given to the right subjects at the right time. Many studies on the antioxidant capacity assessed by various available methods showed inconsistent results and the assessment of antioxidant capacity has been the subject of extensive studies and arguments. This study was performed to elucidate the basic chemistry required for the development of a reliable method for the assessment of antioxidant capacity for radical scavenging in vitro. In this study, the capacity of α-tocopherol and its related compounds, ascorbic acid, and uric acid for scavenging radicals was assessed from their effects on the rate of decay of hydrophilic and lipophilic probes with various reactivities toward free radicals induced by hydrophilic and lipophilic radicals in homogeneous solution and heterogeneous micelle systems. Fluorescein, pyranine, and pyrogallol red were used as hydrophilic probes, and BODIPY and N,N-diphenyl-p-phenylenediamine were used as lipophilic probes. We show that the rate and amount of radical scavenging by antioxidants, termed the antioxidant radical absorbance capacity, could be assessed by an appropriate combination of radical initiator and probe. This method was applied to the assessment of radical-scavenging capacity of human plasma, wine, and green tea powder.

Rationale for antioxidant supplementation in sarcopenia

Sarcopenia is an age-related clinical condition characterized by the progressive loss of motor units and wasting of muscle fibers resulting in decreased muscle function. The molecular mechanisms leading to sarcopenia are not completely identified, but the increased oxidative damage occurring in muscle cells during the course of aging represents one of the most accepted underlying pathways. In fact, skeletal muscle is a highly oxygenated tissue and the generation of reactive oxygen species is particularly enhanced in both contracting and at rest conditions. It has been suggested that oral antioxidant supplementation may contribute at reducing indices of oxidative stress both in animal and human models by reinforcing the natural endogenous defenses. Aim of the present paper is to discuss present evidence related to possible benefits of oral antioxidants in the prevention and treatment of sarcopenia.

Comparison of the content of bioactive substances and the inhibitory effects against rat plasma oxidation of conventional and organic hot peppers (Capsicum annuum L.)

The aim of this study was to evaluate the chemical compositions and antioxidative activities of hot pepper fruits cultivated with strict management by organic and conventional agricultural practices. The ascorbic acid content in the organically grown hot pepper (OGP) was significantly higher than that of conventionally grown hot pepper (CGP) in both green and red fruits. The content of other bioactive compounds such as flavonoids (apigenin, luteolin, quercetin) and total phenolics in OGP was typically higher than in CGP regardless of fruit color. In addition, the ABTS(+) radical-scavenging activity of OGP red fruits was significantly higher than that of CGP red fruits. Moreover, regardless of the color of the fruits, a higher antioxidative activity was observed in blood plasma from rats administered the OGP fruit extracts than in blood plasma from rats administered the CGP fruit extracts. It was hypothesized that the higher antioxidant activity of the OGP fruits may have resulted from the higher antioxidant content in the OGP fruits. These results suggest that consumption of pepper fruits may increase antioxidant activity in the blood, and OGP fruits may be more effective in increasing this antioxidant activity than CGP fruits.

Levels of lipid peroxidation in human plasma and erythrocytes: comparison between fatty acids and cholesterol

Lipid peroxidation has gained renewed attention with increasing evidence showing its biological role in producing toxic compounds and cellular signaling mediators. The assessment of lipid peroxidation levels in vivo is difficult partly because lipids are oxidized by different oxidants by different mechanisms to give versatile types of products, which may undergo metabolism and secondary reactions. In the present study, total hydroxyoctadecadienoic acids (tHODE) and 7alpha- and 7beta-hydroxycholesterol (t7-OHCh) from 44 healthy human subjects were assessed as biomarkers after reduction with sodium borohydride followed by saponification with potassium hydroxide comparing with the prevailing standard 8-isoprostaglandin F(2alpha) (t8-iso-PGF(2alpha)). The average concentrations of tHODE, total 8-isoprostaglandin F(2alpha) (t8-iso-PGF(2alpha)), t7alpha-OHCh, and t7beta-OHCh were 203, 0.727, 87.1, and 156 nmol/l plasma and 1,917, 12.8, 1,372, and 3,854 nmol/l packed erythrocytes, respectively. The ratios of tHODE and t7-OHCh to the parent substrates were 194 and 3,519 micromol tHODE/mol linoleates and 40.9 and 686 micromol t7-OHCh/mol cholesterol in plasma and erythrocytes, respectively. It was found that (1) t7-OHCh in blood was unexpectedly high, as high as or even higher than tHODE, (2) the amounts of tHODE was more than 100 fold higher than t8-iso-PGF(2alpha) (3) the level of lipid oxidation products in erythrocytes was higher than that in plasma, and (4) lipid peroxidation products level tended to increase while antioxidant level decrease with age. These products may be used as potential biomarker for assessment of lipid peroxidation and oxidative stress in vivo.

Screening of potentially toxic chalcogens in erythrocytes

Previous literature reports have demonstrated that a number of human diseases, including inflammation and cancer, can be caused by environmental and occupational exposure to toxic compounds, via DNA damage, protein modifications, or lipid peroxidation. The present study was undertaken to screen the toxicity of a variety of chalcogens using erythrocytes as a model of cell injury. The toxicity of these compounds was evaluated via quantification of hemolysis and lipid peroxidation. The present investigation shows that diphenyl ditelluride and phenyl tellurides are toxic to erythrocytes. The organoselenium compounds were not toxic to erythrocytes even when tested at high concentrations and with a hematocrit of 45%. The hemolytic effect of tellurides was not positively correlated with thiobarbituric acid-reactive substance (TBARS) production suggesting that lipid peroxidation is not involved in the hemolysis provoked by organotellurium compounds. The results suggest that chalcogen compounds may be toxic to human erythrocytes, depending on their structure.

Effect of lipid-hydroperoxide-induced oxidative stress on vitamin E, ascorbate and glutathione in the rabbit retina

BACKGROUND

It is possible that oxidative stress causes several retinal diseases. However, the natural biogenic role of antioxidants in the retina is not clear.

PURPOSE

This study investigates the change in concentration of vitamin E (VE), ascorbate and glutathione (GSH) in the retina following vitreous injection of 600 mug 18:2 linoleic acid hydroperoxide (LHP) in male New Zealand rabbits.

METHOD

LHP was injected above the retinal surface. The animals were sacrificed and the eyes enucleated before LHP injection, 1, 3, 6, 12, 24 h and 4 and 7 days after LHP injection. Retinas were removed, VE and ascorbate measured by HPLC, and GSH determined by a fluorometric method.

RESULTS

The concentration of VE in the retina decreased from pretreatment levels of 154.6 +/- 29.7 nmol/g wet weight (n = 7) and was lowest at 6 h (61.1 +/- 18.1 nmol/g wet weight, n = 4, p < 0.05), then increased gradually, returning slowly to pre-LHP levels by 7 days. The concentration of ascorbate in control retinas decreased at 6 h from pretreatment levels of 7.33 +/- 0.93 micromol/g wet weight (n = 7) to 2.74 +/- 0.16 micromol/g wet weight (n = 4, p < 0.05) and returned to pretreatment levels rapidly by 24 h after injection. The concentration of GSH in retinas decreased from baseline levels of 109.53 +/- 8.19 microg/g wet weight (n = 9), was lowest at 12 h (72.40 +/- 11.17 microg/g wet weight, n = 5, p < 0.05) and returned to pretreatment levels by 7 days.

CONCLUSION

The results suggest that intravitreous LHP injection is a contributor to oxidative stress in the rabbit retina by causing a reduction in antioxidant capacity.

Effects of melatonin and vitamin E on oxidative-antioxidative status in rats exposed to irradiation

Bone marrow is known to be particularly susceptible to radiation. In this study, the effects of treatment with Vitamin E and melatonin and irradiation-induced lipid peroxidation and its association with antioxidant enzymes in the total bone (bone and bone marrow) and skeletal muscle of rats subjected to total body irradiation was investigated. Wistar-Albino rats were intraperitoneally treated with 100mg/kg Vitamin E or melatonin before exposure to 720cGy irradiation. Control, irradiation, Vitamin E plus irradiation, melatonin plus irradiation groups were sacrificed by decapitation under ether anaesthesia on the 10th day after irradiation exposure. Application of total body irradiation elevated malondialdehyde (MDA) levels in rat skeletal muscle (p<0.001), but glutathione peroxidase (GSH-Px) and catalase activities remained unchanged. Application of Vitamin E with irradiation or melatonin decreased the MDA levels in skeletal muscle (p<0.01), but did not affect the GSH-Px and catalase activity. MDA levels were found elevated in total bone (p<0.001), GSH-Px activity decreased (p<0.001) and catalase activity remained unchanged in the group treated with irradiation. Application of Vitamin E with irradiation increased the GSH-Px activity in total bone (p<0.01), but the activity of MDA and catalase remained unchanged. Treatment of the animals with melatonin concurrent with total body irradiation reduced the degree of lipid peroxidation and elevation in antioxidant enzymes in total bone (p<0.01). We conclude that melatonin may protect the total bone from the damaging effects of irradiation exposure, and its actions protect total bone from oxidative stress. However, protective effects of Vitamin E were not observed in this study.

A role for homocysteine increase in haemolysis of megaloblastic anaemias due to vitamin B12 and folate deficiency: results from an in vitro experience

Megaloblastic anaemias (MA) are frequently associated with haemolysis. The pathogenesis of these finding is not clear, but it is thought to depend on the greater destruction of abnormal and fragile megaloblastic erythrocytes. Vitamin B(12) and folate deficiencies are the commonest cause of MA; these deficiencies may simultaneously induce a significant alteration in homocysteine metabolism leading to hyperhomocysteinemia. Blood cells have enzymes involved in homocysteine metabolism. Considering the possible effects of hyperhomocysteinemia in erythrocyte toxicity (due to oxidative damage and/or to interaction with sulfhydryl residues of structural and enzymatic proteins), the aim of our study was to evaluate (1) the homocysteine blood cells production in patients with MA due to vitamin B(12) and folate deficiency and (2) the possible role and mechanism of hyperhomocysteinemia in MA haemolysis. After incubation at 37 degrees C, blood samples from MA patients showed higher and significant levels of Hcy, LDH, lipid peroxidation parameters (MDA), and ghost protein-bound Hcy than controls. Haemolysis (%) was higher in MA patients than controls and was significantly correlated with Hcy accumulation in the medium, lipid peroxidation indices and ghost protein-bound Hcy. No significant (or significantly lower) alterations through time in considered parameters were observed in the corresponding samples incubated at 4 degrees C or in samples incubated with methionine-free medium (lower Hcy production). Our data, deriving from an in vitro experience, suggest a possible role of Hcy accumulation due to vitamin B(12) and folate deficiencies in haemolysis associated to MA due to vitamin deficiency.

Lidocaine has better antioxidant potential than ropivacaine and bupivacaine: in vitro comparison in a model of human erythrocytes submitted to an oxidative stress

BACKGROUND

Local anesthetic agents may exert antioxidant properties in various models. The aim of this work was to compare the antioxidant properties of lidocaine, bupivacaine and ropivacaine using an in vitro model of human erythrocytes submitted to an oxidative stress.

METHODS

Blood was obtained from healthy volunteers. After separation, erythrocytes were suspended in phosphate buffer. Oxidative stress was induced by incubation with 2,2'-azobis (2-amidinopropane) hydrochloride (AAPH). (1) Effects of four different concentrations (50, 100, 300 and 600 microg ml(-1)) of lidocaine, bupivacaine and ropivacaine were studied in absence or presence of AAPH (20 mM). Potassium efflux was assessed by flame photometry. (2) Effects of 50 and 600 microg ml(-1) of lidocaine, bupivacaine and ropivacaine on AAPH (50 mM) induced hemolysis were also studied. (3) The oxygen radical absorbing capacity of lidocaine, bupivacaine and ropivacaine at the four concentrations was evaluated by the analysis of the allophycocyanin fluorescence.

RESULTS

In absence of AAPH, neither extracellular potassium nor hemolysis was noted. AAPH (20 mM) induced a significant increase in extracellular potassium that was reduced by all local anesthetic agents, with greater effects for lidocaine. AAPH-induced hemolysis was significantly decreased by all the local anesthetic agents at higher concentration, but only by lidocaine at 50 microg ml(-1). Finally, none of the local anesthetic agents modified the allophycocyanin fluorescence.

CONCLUSION

In this model, lidocaine was proved more effective than bupivacaine and ropivacaine in protecting human erythrocytes submitted to an oxidative challenge. This was not due to a free radical scavenging effect.

Age-related thymic atrophy in the guinea pig

We have characterized age-related thymic atrophy in the guinea pig, including identification of antibodies that allow immunohistochemical assessment of thymopoiesis. Age-related thymic atrophy in guinea pigs more closely resembles what occurs in humans histologically and in thymus weight, cellularity, and percent functional area than do other rodent models. The guinea pig model is thus particularly well-suited to study the role of the thymic perivascular space in age-related thymic atrophy. We next tested the hypothesis that dietary supplementation with Vitamin C could prevent or delay age-related thymic atrophy. Thymus histology, weight, cellularity, and percent functional area did not differ at 12 months between groups that received 3, 30, or 150 mg Vitamin C daily from 4 months of age. Thus long-term supplementation with up to 130 mg/kg/day Vitamin C is insufficient to influence the time course and extent of age-related thymic atrophy in guinea pigs.

Vitamins and arthritis. The roles of vitamins A, C, D, and E

There are at least four mechanisms whereby the nutrient vitamins A, C, D, and E may be related to the processes that impede or give rise to OA. These nutrient vitamins have major roles in modulating oxidative stress, participating in immune responses, and contributing to cell differentiation. There is a substantial need to understand the contribution of these nutrients to OA, because they may provide important insight into ameliorating the initiation and progression of the disease. Simultaneously, greater understanding will add rationality to an area of potential intervention that is often based on anecdote. Investigation will be complex; there is the need to select appropriate systems. Typical animal model systems used in the study of OA are inappropriate because most animals can synthesize ascorbic acid. There is the need to disaggregate, as much as possible, the numerous subsets of OA and the plethora of processes that contribute to that heterogeneity. Certainly, there is the need to recognize the interdependency of the actions of each of these nutrients at the cellular level. Furthermore, humans rarely consume these nutrients as independent products. For example, watermelon is a primary source of both ascorbic acid and beta-carotene. Failure to address these complexities denies the scientist the opportunity to advance our understanding of health and disease processes. More importantly, failure to address these complexities denies the person with OA the opportunity to address his or her own health.

Effects of vitamin E and C supplementation on oxidative stress and viral load in HIV-infected subjects

OBJECTIVES

The HIV-infected population is known to be oxidatively stressed and deficient in antioxidant micronutrients. Since in vitro replication of HIV is increased with oxidative stress, this study assessed the effect of antioxidant vitamin supplementation on lipid peroxidation, a measure of oxidative stress, and viral load in humans.

DESIGN

A randomized placebo-controlled, double-blind study.

METHODS

Forty-nine HIV-positive patients were randomized to receive supplements of both DL-alpha-tocopherol acetate (800 IU daily) and vitamin C (1000 mg daily), or matched placebo, for 3 months. Plasma antioxidant micronutrient status, breath pentane output, plasma lipid peroxides, malondialdehyde and viral load were measured at baseline and at 3 months. New or recurrent infections for the 6-month period after study entry were also recorded.

RESULTS

The vitamin group (n = 26) had an increase in plasma concentrations of alpha-tocopherol (P < 0.0005) and vitamin C (P < 0.005) and a reduction in lipid peroxidation measured by breath pentane (P < 0.025), plasma lipid peroxides (P < 0.01) and malondialdehyde (P < 0.0005) when compared with controls (n = 23). There was also a trend towards a reduction in viral load (mean +/- SD changes over 3 months, -0.45 +/- 0.39 versus +0.50 +/- 0.40 log10 copies/ml; P = 0.1; 95% confidence interval, -0.21 to -2.14). The number of infections reported was nine in the vitamin group and seven in the placebo group.

CONCLUSION

Supplements of vitamin E and C reduce oxidative stress in HIV and produce a trend towards a reduction in viral load. This is worthy of larger clinical trials, especially in HIV-infected persons who cannot afford new combination therapies.

Enhancement of nitroxide-reducing activity in rats after chronic administration of vitamin E, vitamin C, and idebenone examined by an in vivo electron spin resonance technique

Rats were given vitamin E (Vit-E), idebenone (ID), or vitamin C (Vit-C) in their food for 2 or 4 weeks. After feeding, the ability of rats to reduce 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempol) in terms of the half-life of Tempol was examined as a specific marker. Tempol was repeatedly injected intravenously, and its half-life was serially evaluated by an in vivo electron spin resonance (ESR) technique. The radical-reducing ability in rats was enhanced differently by Vit-E, ID, and Vit-C, i.e., slow onset of the ability after Vit-E and ID (lipid-soluble antioxidants) and fast onset after Vit-C (a water-soluble antioxidant).

Immune function in aged women is improved by ingestion of vitamins C and E

We have investigated the effects of supplementation of the diet with the antioxidant vitamins C and E on several functions of the immune response of aged women. Ten healthy women and 20 women (72 ± 6 years old) suffering two diseases often associated with age (10 with major depression disorders, MDD, and 10 with coronary heart disease, CHD) were administered 1 g of vitamin C and 200 mg of vitamin E daily for 16 weeks. Blood samples were collected before and after treatment for measurement of several immunological functions, namely proliferative response of lymphocytes to the mitogen phytohemagglutinin (20 mg/L) and phagocytic functions of polymorphonuclear (PMN) neutrophils, i.e., adherence to vascular endothelium, chemotaxis, phagocytosis of latex beads, and superoxide anion production. In addition, we also determined the levels of serum cortisol and lipid peroxides. Intake of vitamins resulted in a significant increase in the lymphoproliferative capacity and in the phagocytic functions of PMN neutrophils as well as in a significant decrease of serum levels of lipid peroxides and cortisol, both in the healthy aged women and in the aged women with MDD or CHD. These findings suggest an important role of antioxidant supplementation in the improvement of immune function in aged females as well as in the prevention and treatment of specific diseases associated with age that are quite prevalent in the developed countries.Key words: vitamins C and E, ageing, lymphocytes, neutrophils, lipid peroxides, cortisol.

Antioxidant activity of a novel vitamin E derivative, 2-(alpha-D glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol

A novel vitamin E derivative, 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG), has excellent water-solubility (> 1 x 10[3] mg/ml). The antioxidant activity of TMG was investigated. Kinetic studies of the inhibition of radical-chain reaction of methyl linoleate in solution demonstrated that the peroxyl radical-scavenging activity was not changed by the replacement of phytiyl side chain of vitamin E to glucosyl group. TMG acted as an effective inhibitor on lipid peroxidation of egg yolk phosphatidylcholine (PC)-liposomal suspension induced by a water-soluble and a lipid-soluble radical generator, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN). Its effectiveness was higher than that of ascorbic acid (AsA) when liposomal suspension was exposed to a lipid-soluble radical generator, AMVN. TMG also showed an excellent antioxidant activity on cupric ion-induced lipid peroxidation of PC-liposomal suspension, and suppressed the oxidation of rat brain homogenate which contained trace level of iron ion. On the other hand, AsA acted as a prooxidant on both the cupric ion-induced liposomal peroxidation and the oxidation of rat brain homogenate. When human plasma was exposed to either AAPH or AMVN, the accumulation of cholesteryl ester hydroperoxides was retarded by the addition of TMG.

2,2'-Azobis (4-methoxy-2,4-dimethylvaleronitrile), a new lipid-soluble azo initiator: application to oxidations of lipids and low-density lipoprotein in solution and in aqueous dispersions

Both hydrophilic and hydrophobic azo radical initiators are useful for in vitro studies on lipid peroxidation and its inhibition by antioxidants. In the present study, a new lipophilic azo compound, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (MeO-AMVN), was introduced and its action as an initiator of lipid peroxidation was examined. MeO-AMVN decomposed about 15 times as fast as 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN), a widely used lipophilic azo initiator, and MeO-AMVN-initiated free radical-mediated peroxidations of lipids in organic solution and in micelles, membranes, and low-density lipoprotein in aqueous dispersions with much smaller concentration than AMVN. The rate of chain initiation by MeO-AMVN varied significantly with the medium and decreased with increasing viscosity of the medium. The advantage and cautions for using MeO-AMVN as a lipophilic radical source have been discussed and it has been concluded that MeO-AMVN, when properly used, is a useful radical initiator of lipid peroxidations especially in micelles, membranes, and lipoproteins.

Influence of antioxidants on the quality of stored blood

BACKGROUND AND OBJECTIVES

Blood is exposed to oxidation stress and therefore has a high antioxidant capacity (AOC). With the many factors increasing the demands on the AOC, there may be damage to erythrocytes by free radicals. This study was to investigate evidence of erythrocyte damage in stored donor blood and to affect this by premedication of blood donors.

MATERIALS AND METHODS

Blood samples of 15 healthy donors were collected in CPDA-1 solution and analyzed immediately, and then again after 10 days of incubation at 4 degrees C and 1 day of incubation at 37 degrees C. Prior to incubation, the following parameters were evaluated: Na+, K+, malondialdehyde (MDA), hemoglobin (Hb), AOC in the supernatant, superoxide dismutase (SOD) in erythrocytes, and glutathione peroxidase (GSHPx) in whole blood. Blood donors of group 1 were not given any drugs or vitamins before blood sampling. The same blood donors were then supplemented with the following daily doses of antioxidants for 10 days before the next blood sampling: 36 mg of beta-carotene, 300 mg of vitamin E, 200 mg of vitamin C, and 40 mg of selenium.

RESULTS

The blood from donors of group 2 had a significantly smaller increase in MDA, K+, and Hb, and a smaller decrease in Na+ and AOC in the supernatant compared with that of group 1, while the activity of SOD and GSHPx did not change during blood storage.

CONCLUSIONS

These results suggest that antioxidants given to blood donors can improve red cell storage parameters by reducing cell damage caused by free radicals.

Inhibition of oxidation of low density lipoprotein by troglitazone

The effect of a new oral hypoglycemic agent troglitazone, (+/-)-5-[4-(6-hydroxy-2,5,7,8-tetramethylchroman-2-yl-methoxy)benz yl]-2,4-thiazolidinedione as an antioxidant against the free radical-mediated oxidation of low density lipoprotein (LDL) was studied. The oxidation of LDL gives cholesteryl ester hydroperoxide and phosphatidylcholine hydroperoxide as major primary products. Troglitazone incorporated exogenously into LDL inhibited the oxidations of LDL induced by either aqueous or lipophilic peroxyl radicals and suppressed the formation of lipid hydroperoxides efficiently. Ascorbic acid added into the aqueous phase spared both endogenous alpha-tocopherol and troglitazone in LDL. It was also found by absorption spectroscopic and electron spin resonance (ESR) studies that troglitazone reacted rapidly with a galvinoxyl radical to give a chromanoxyl radical which gives the same ESR spectrum as alpha-tocopherol. This ESR spectrum disappeared rapidly when ascorbic acid was added into the system. These results show that troglitazone acts as a potent antioxidant and protects LDL from oxidative modification.

Whole body X-ray irradiation to mice decreases ascorbic acid concentration in bone marrow: comparison between ascorbic acid and vitamin E

The change in the ascorbic acid concentration in the bone marrow after whole body X-ray irradiation was compared with that in the vitamin E concentration. The ascorbic acid concentration in the bone marrow significantly decreased by 30% 1 h after exposure to 3 Gy of X-rays, whereas the vitamin E concentration in the bone marrow was significantly decreased 5 h after exposure, when the level of ascorbic acid was less than 10% of that in the control. At 24 h after exposure, the ascorbic acid concentration in the bone marrow was significantly decreased by 80% after exposure to 0.5 Gy, whereas the vitamin E concentration was significantly decreased after exposure to 1 Gy or more. In the bone marrow, the decrease in the ascorbic acid concentration was accompanied by a marked increase in the concentration of dehydroascorbic acid, an oxidized form of ascorbic acid. X-ray irradiation did not decrease either the ascorbic acid or vitamin E concentration in the serum or intestine. These findings suggest that the bone marrow is more highly susceptible to oxidative damage by radiation and that ascorbic acid plays an important defense role against it. On Day 8 after irradiation, the decreases in the vitamin E and ascorbic acid concentrations in the bone marrow showed recovery after exposure to 3 Gy, but not after the exposure to 6 Gy.

Hepatic damage induced by perfusion of radical generating azo compound and its inhibition by vitamin E

The damaging effect of perfusion of hydrophilic radical generating azo compound on the liver of normal and vitamin E-deficient rats and its inhibition by antioxidants were studied in order to increase understanding of the action of free radicals on biological tissues. The hepatic damage was evaluated from the release of cytosolic enzymes such as glutamic oxaloacetic transaminase and glutamic pyruvic transaminase, mitochondrial oxidation metabolism and morphological change. Two kinds of hydrophilic azo compounds were used, one which decomposes spontaneously at a uniform rate to generate free radicals and the other which does not. The former induced hepatic damage in a dose-dependent manner, while the latter did not exert any damage. Both endogenous vitamin E in the membranes and a water soluble vitamin E analogue added simultaneously with a radical initiator suppressed the hepatic damage. These results show that the hepatic damage induced by perfusion of radical generating azo compound is caused not by the azo compound itself but by free radicals.

Lipoperoxidation induced by hydrogen peroxide in human erythrocyte membranes. 2. Comparison of the antioxidant effect of Ginkgo biloba extract (EGb 761) with those of water-soluble and lipid-soluble antioxidants

An in vitro model using healthy human erythrocyte suspensions was used to compare the antioxidant effect of standardized Ginkgo biloba extract (EGb 761) with those of water-soluble (ascorbic acid, glutathione and uric acid) and lipid-soluble (alpha-tocopherol and retinol acetate) antioxidants. Lipid peroxidation was induced by hydrogen peroxide in the absence (control) and presence of antioxidants at low (25 micrograms/ml) and high (250 micrograms/ml) concentrations. Malondialdehyde production was determined as the indicator of lipid peroxidation during the incubation period. The results suggest that all of the antioxidants, except ascorbic acid, have antioxidant potential in this system in a concentration-dependent manner. When the antioxidants were compared, EGb 761 was found to be more effective than water-soluble antioxidants, and as effective as lipid-soluble antioxidants. Among the lipid-soluble antioxidants there was no significant difference in potency between alpha-tocopherol and retinol acetate, but uric acid was the most potent of the water-soluble antioxidants. The antioxidant potency of EGb 761 appears to be comparable with that of the well-known antioxidants alpha-tocopherol and retinol acetate.

Singlet oxygen induces predominantly G to T transversions on a single-stranded shuttle vector replicated in monkey cells

To elucidate the mechanisms of mutagenesis by singlet oxygen DNA damage in mammalian cells, a SV40-derived single-stranded shuttle vector was exposed to the water soluble endoperoxide 3,3'-(1,4-naphthylidene) dipropionate (NDPO2). The damaged vector was transfected into monkey COS7 cells and the plasmid progeny exhibited up to 10 fold increase on the mutation frequency in the supF target gene, when compared to untreated vector. The sequence in the supF locus of such mutants revealed that singlet oxygen-induced mutagenesis in single-stranded vector is significantly different from spontaneous mutagenesis. Among the base substitutions, most of the mutations involved deoxyguanosines, being G to T transversions the predominant type of change. The data indicate that mutagenesis by singlet oxygen in mammalian cells may be generated by an error prone bypass of damaged deoxyguanosines at the template DNA.

Inhibition of photohemolysis by copper(II) complexes with SOD-like activity

Red blood cell lysis photosensitized by Ketoprofen, 2-(3-benzoxyphenyl)propionic acid (KPF), was investigated in the presence of some copper(II) complexes with linear and cyclic dipeptides as well as functionalized beta-cyclodextrins with SOD-like activity with the aim of ascertaining their protective activity towards the photoinduced cell damage. The comparison between the decrease of photolytic activity caused by these complexes and their superoxide dismutase activity showed an appreciable correlation. The correct determination of species existing in experimental conditions was obtained through a simulation approach based on the knowledge of the stability constants of the complexes.

Prolonged storage of red cells: the effect of pH, adenine and phosphate

Prolonged storage of red blood cells (RBCs) at 4 degrees C results in decreased intracellular ATP levels with diminished posttransfusion survival. Meryman described a preservative medium, exceptional in its capacity to increase these intracellular levels during the first weeks of storage and later in maintaining adequate levels, for extended storage periods. We modified this medium, investigated its constituents, and found that its ATP-preserving effect was unrelated to its tonicity or to the presence of mannitol. Throughout storage, RBC potassium leakage and lactate production were moderate. No evidence of osmotic swelling was detected. In spite of high ATP levels, the cells became echinocytes, thus discounting a direct correlation between shape and metabolic status. The most striking finding in this study was that the prestorage pH of the blood unit (pH 7.0), has a crucial contribution in elevating nucleotide levels in a medium containing high levels of phosphate (18-40 mM) and adenine. We suggest that a combined effect of optimal pH, adenine, glucose and phosphate in the medium contributes to the ability of the RBCs to synthesize the necessary purine nucleotides by the 'salvage pathway'.

Consumption of thermally-oxidized sunflower oil by chicks reduces alpha-tocopherol status and increases susceptibility of tissues to lipid oxidation

The effect of heated sunflower oil consumption on alpha-tocopherol status, fatty acid composition and oxidative stability of chicken tissues was investigated. Chicks were fed on diets containing (g/kg): fresh sunflower oil (FSO) 40, heated sunflower oil (HSO) 40 or heated sunflower oil (40) supplemented with alpha-tocopheryl acetate (HSE) to a similar alpha-tocopherol concentration as the FSO diet. Concentrations of alpha-tocopherol in tissues of chicks fed on HSO and HSE were significantly lower than those of chicks fed on FSO. Significant correlations were observed between plasma alpha-tocopherol concentration and the alpha-tocopherol concentrations of other tissues (r > or = 0.67, P < 0.005) and between log plasma alpha-tocopherol and plasma thiobarbituric acid-reacting substances (TBARS) concentrations (r -0.851, P < 0.001). The concentrations of TBARS in tissues of chicks fed on the various diets were generally very similar before stimulation of peroxidation with Fe-ascorbate. Susceptibility of tissues to Fe-ascorbate-induced lipid peroxidation was increased by feeding HSO. Supplementation with alpha-tocopheryl acetate reduced susceptibility to lipid oxidation to varying degrees, depending on the tissue. The results suggest that chronic ingestion of oxidized lipids may compromise free-radical-scavenging activity in vivo by depleting alpha-tocopherol in the gastrointestinal tract, or possibly in plasma and other tissues.