The inhibition of radical-initiated peroxidation of microsomal lipids by both alpha-tocopherol and beta-carotene

β-Carotene extracted from Blakeslea trispora attenuates oxidative stress, inflammatory, hepatic injury and immune damage induced by copper sulfate in zebrafish (Danio rerio)

β-Carotene, as a kind of potent antioxidant compounds, has gained extensive attention. Blakeslea trispora, a filiform aerobic fungus, has been proposed as a natural source of β-carotene for commercial exploitation. However, it has not yet been investigated whether β-carotene extracted from Blakeslea trispora can attenuate oxidative stress, inflammatory, liver injury and immune damage of zebrafish (Danio rerio) exposed to copper sulfate (CuSO₄). In this study, we evaluated the effects of β-carotene on migration of GFP-labeled neutrophils, histological changes of liver, markers of oxidative, inflammatory cytokines and transaminase analysis, as well as the expression and activities of apoptosis, immune-related certain genes in zebrafish treated with different concentrations of β-carotene (0, 10, 20, 40 μg/mL) after exposure to CuSO₄. The results indicated that β-carotene reduced migration of neutrophils and released liver damage. What's more, β-carotene was found to reduce the index levels of oxidative stress response (HMOX-1, reactive oxygen species (ROS), NADPH, MDA), inflammatory factors (interleukine-1β (IL-1β), interleukine-6 (IL-6), interleukine-8 (IL-8), tumor necrosis factor-α (TNF-α)), liver function protein (AST, ALT) which increased by CuSO₄. β-Carotene also promoted the activities of SOD, GSH-Px, ACP, AKP and LZM and increased the protein of immune-related factors, IgM and IFN-γ after exposure to CuSO₄. Thus, our results demonstrate that β-carotene has an antioxidant, anti-inflammatory and hepatoprotective activity and participation in immunoregulation.

Role of Antioxidants in Horse Serum-mediated Vasculitis in Swine: Potential Relevance to Early Treatment in Mitigation of Coronary Arteritis in Kawasaki Disease

BACKGROUND

Horse serum-induced immune complex coronary vasculitis in swine is the first experimental model to mimic most of the pictures of Kawasaki disease. Immune complex mechanism has been implicated as one of the possible mechanisms in the pathogenesis of vasculitis in Kawasaki disease. Antioxidants have a significant role in the reduction of cardiovascular diseases in both human and animal studies. We tried giving vitamins A, E, and C to treat immune complex vasculitis, in the hope of mitigating coronary vasculitis in Kawasaki disease.

METHODS

Our study group consisted of 30 pure bred male piglets of 2-3 months of age, and they were divided into test and control groups. The test (AEC) group (n = 20) received two doses of horse serum, 10 mL (0.65 g protein)/kg body weight at 5-day intervals, and oral vitamins A, E, and C once daily for 14 days. The control group (n = 10) was further divided into the saline group (n = 3) receiving two doses of normal saline and the horse serum group (n = 7) receiving two doses of horse serum at 5-day intervals. Piglets were observed for the rashes and coronary artery dimensions.

RESULTS

Both the AEC and the control horse serum group developed rashes after horse serum infusions, but the AEC group developed significantly fewer rashes, and no rashes were seen in the saline group. The control horse serum group (mean ± standard deviation = 2.13 ± 0.72) showed significant coronary artery dilatation, whereas there was no significant dilatation in the AEC group (mean ± standard deviation = 0.81 ± 0.58) or the control saline group (p = 0.002).

CONCLUSION

Serum sickness is a prototype of immune complex vasculitis, and the severity can be ameliorated with antioxidants. A trial of therapeutic dosages of vitamins A, E, and C in acute phase of Kawasaki disease, may be effective in mitigation of coronary artery lesion in addition to intravenous immunoglobulin and aspirin.

Effects of β-Carotene and Its Cleavage Products in Primary Pneumocyte Type II Cells

β-Carotene has been shown to increase the risk of developing lung cancer in smokers and asbestos workers in two large scale trails, the Beta-Carotene and Retinol Efficacy Trial (CARET) and the Alpha-Tocopherol Beta-carotene Cancer Prevention Trial (ATBC). Based on this observation, it was proposed that genotoxic oxidative breakdown products may cause this effect. In support of this assumption, increased levels of sister chromatid exchanges, micronuclei, and chromosomal aberrations were found in primary hepatocyte cultures treated with a mixture of cleavage products (CPs) and the major product apo-8′carotenal. However, because these findings cannot directly be transferred to the lung due to the exceptional biotransformation capacity of the liver, potential genotoxic and cytotoxic effects of β-carotene under oxidative stress and its CPs were investigated in primary pneumocyte type II cells. The results indicate that increased concentrations of β-carotene in the presence of the redox cycling quinone dimethoxynaphthoquinone (DMNQ) exhibit a cytotoxic potential, as evidenced by an increase of apoptotic cells and loss of cell density at concentrations > 10 µM. On the other hand, the analysis of micronucleated cells gave no clear picture due to the cytotoxicity related reduction of mitotic cells. Last, although CPs induced significant levels of DNA strand breaks even at concentrations ≥ 1 µM and 5 µM, respectively, β-carotene in the presence of DMNQ did not cause DNA damage. Instead, β-carotene appeared to act as an antioxidant. These findings are in contrast with what was demonstrated for primary hepatocytes and may reflect different sensitivities to and different metabolism of β-carotene in the two cell types.

The effect of conjugated linoleic acid supplements on oxidative and antioxidative status of dairy cows

Dairy cows develop frequently negative energy balance around parturition and in early lactation, resulting in excessive mobilization of body fat and subsequently in increased risk of ketosis and other diseases. Dietary conjugated linoleic acid (CLA) supplements are used in dairy cows mainly for their depressing effect on milk fat content, but are also proposed to have antioxidative properties. As negative energy balance is associated with oxidative stress, which is also assumed to contribute to disease development, the present study was conducted to examine effects of CLA on oxidative and antioxidative status of lactating dairy cows. German Holstein cows (primiparous n=13, multiparous n=32) were divided into 3 dietary treatment groups receiving 100g/d of control fat supplement, containing 87% stearic acid (CON; n=14), 50g/d of control fat supplement and 50g/d of CLA supplement (CLA 50; n=15), or 100g/d of CLA supplement (CLA 100; n=16). The CLA supplement was lipid-encapsulated and contained 12% of trans-10,cis-12 CLA and cis-9,trans-11 CLA each. Supplementation took place between d1 and 182 postpartum; d 182 until 252 postpartum served as a depletion period. Blood was sampled at d -21, 1, 21, 70, 105, 140, 182, 224, and 252 relative to calving. The antioxidative status was determined using the ferric-reducing ability of plasma, α-tocopherol, α-tocopherol-to-cholesterol mass ratio, and retinol. For determination of oxidative status concentrations of hydroperoxides, thiobarbituric acid-reactive substances (TBARS), N'-formylkynurenine, and bityrosine were measured. Mixed models of fixed and random effects with repeated measures were used to evaluate period 1 (d -21 to 140) and 2 (d182-252) separately. Cows showed increased oxidative stress and lipid peroxidation during the periparturient period in terms of increased serum concentrations of hydroperoxides and TBARS, which decreased throughout lactation. During period 1, the supplemented cows had lower TBARS concentrations, which was not detectable in period 2. The other determined parameters were not affected by CLA supplementation. The obtained results show that dietary CLA supplementation in the chosen dosage, formulation, and application period had a marginal antioxidative effect in terms of lipid peroxidation in lactating dairy cows.

Lipid profiles, in vitro digestion and oxidative stability of mutton bird oil

The lipid profile, in vitro digestion and oxidative stability of mutton bird oil were investigated. Wax ester, triacylglycerol and sterol were the major lipids present as determined using capillary chromatography with flame ionisation detector (Iatroscan). Fatty acid analysis by gas chromatography (GC) showed that wax esters had a higher total omega-3 fatty acids content including EPA, DPA and DHA than TAGs (31 % and 24 %, respectively). In TAGs, (13)C nuclear magnetic resonance (NMR) data showed that EPA was statistically positioned at sn-1,3 and sn-2, while DHA was preferentially at sn-2. In vitro digestion using porcine pancreatic lipase resulted in 75 % of TAG and 10 % wax ester hydrolysis in 120 min. As reflected in the measured conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS) values during accelerated oxidation at 60 °C for 5 days, the oil was relatively stable against oxidation considering its high omega-3 content.

Analytical tools for the analysis of β-carotene and its degradation products

β-Carotene, the precursor of vitamin A, possesses pronounced radical scavenging properties. This has centered the attention on β-carotene dietary supplementation in healthcare as well as in the therapy of degenerative disorders and several cancer types. However, two intervention trials with β-carotene have revealed adverse effects on two proband groups, that is, cigarette smokers and asbestos-exposed workers. Beside other causative reasons, the detrimental effects observed have been related to the oxidation products of β-carotene. Their generation originates in the polyene structure of β-carotene that is beneficial for radical scavenging, but is also prone to oxidation. Depending on the dominant degradation mechanism, bond cleavage might occur either randomly or at defined positions of the conjugated electron system, resulting in a diversity of cleavage products (CPs). Due to their instability and hydrophobicity, the handling of standards and real samples containing β-carotene and related CPs requires preventive measures during specimen preparation, analyte extraction, and final analysis, to avoid artificial degradation and to preserve the initial analyte portfolio. This review critically discusses different preparation strategies of standards and treatment solutions, and also addresses their protection from oxidation. Additionally, in vitro oxidation strategies for the generation of oxidative model compounds are surveyed. Extraction methods are discussed for volatile and non-volatile CPs individually. Gas chromatography (GC), (ultra)high performance liquid chromatography (U)HPLC, and capillary electrochromatography (CEC) are reviewed as analytical tools for final analyte analysis. For identity confirmation of analytes, mass spectrometry (MS) is indispensable, and the appropriate ionization principles are comprehensively discussed. The final sections cover analysis of real samples and aspects of quality assurance, namely matrix effects and method validation.

Singlet oxygen autoxidation of vegetable oils: evidences for lack of synergy between β-carotene and tocopherols

The synergy between β-carotene and tocopherols--antioxidants protecting oils from oxidation, was analyzed in a model system. The model used stripped borage and evening primrose oils. A chlorophyll extract, β-carotene and one of the tocopherols were added together or separately to the oils. Oil oxidation was initiated by singlet oxygen that was produced by chlorophylls irradiated with the use of a xenon lamp equipped with the cut-off 600 nm filter. Experiments were carried out at two mole ratios of tocopherols to β-carotene, i.e. at 1:1 and 23:1. Analyses were performed using absorption and fluorescence spectra in the UV+Vis region. The results demonstrated an antagonistic action of the antioxidants. The protective effect of unsaturated fatty acids was significantly better in the case of β-carotene compared to the tocopherols. Furthermore, tocopherols were less effective in protecting the oils in the presence of β-carotene than without it.

Effects of antioxidants on the stability of β-Carotene in O/W emulsions stabilized by Gum Arabic

The potential of oil-in-water emulsions as a β-carotene delivery system was examined in this study. Oil-in-water (O/W) emulsions containing β-carotene were formed by gum arabic with α-tocopherol, tertiary butyl hydroquinone (TBHQ) and ascorbyl palmitate, respectively. The influence of antioxidants on the chemical degradation of β-carotene in gum arabic stabilized emulsions was investigated at 4, 25, 45 and 65 °C in the dark, respectively. An accelerated photo-oxidation test was carried out at 45 °C (450 W/m(2)). Moreover, β-carotene degradation rate constants (k 1-value), activation energy (E a ) and decimal reduction time (D-value) were estimated to interpret the degradation kinetics. The impact of antioxidants on the thermal stability of β-carotene in diluted emulsions was generally in the following order: α-tocopherol > TBHQ > ascorbyl palmitate. α-Tocopherol was found to be the most effective to the antioxidation of β-carotene at the concentration of 0.10 wt% under light exposure. It was concluded that the stability of β-carotene in oil-in-water emulsions could be improved by the presence of different antioxidants.

beta-Carotene exhibits antioxidant and anti-apoptotic properties to prevent ethanol-induced cytotoxicity in isolated rat hepatocytes

The study was designed to evaluate the effects of 1 microM beta-carotene on antioxidant status in ethanol-treated rat hepatocytes and investigate possible anti-apoptotic mechanisms of beta-carotene in protecting ethanol-induced cytotoxicity. The isolated rat hepatocytes were incubated for 48 h in a medium with or without alcohol (100 mM) and mu-carotene (1 microM) using the following groups: the control (C), beta-carotene (CB), ethanol (E), and ethanol + beta-carotene (EB) groups. The cell viability, antioxidative status, cytochrome P450 2E1 (CYP2E1) and caspase expressions in hepatocytes were measured. The E group demonstrated lower cell viability, glutathione (GSH) levels, and lipid peroxide accumulation in rat hepatocytes; meanwhile, CYP2E1, caspase-3, and caspase-9 expressions increased. In contrast, cell viability, GSH levels, and glutathione reductase (GRD) activity significantly increased while lipid peroxides and expressions of CYP2E1, casapse-3, and caspase-9 decreased in the EB group. The results suggest that ethanol treatment decreases cell viability in rat hepatocytes via induced oxidative stress. 1 muM beta-carotene decreased oxidative stress and prevented ethanol-induced cell death by inhibiting caspase-9 and caspase-3 expression.

Evaluation of activity of selected antioxidants on proteins in solution and in emulsions

Protection against protein oxidation by lipophilic and hydrophilic antioxidants in model systems using bovine serum albumin (BSA) in solution alone, or in an emulsion with linolenic acid methyl ester (LnMe) was found to be strongly dependent on the oxidation initiator. Tocopherol, Trolox, or the carotenoids astaxanthin and canthaxanthin were incubated with BSA or BSA/LnMe and oxidation was initiated either with the water-soluble azo-initiator 2,2' azo-bis-(2-amidinopropane) hydrochloride (AAPH), or FeCl3 and ascorbate, or the Fenton system using FeCl2/EDTA/H2O2, or with the singlet oxygen generating species anthracene-9,10-dipropionic acid disodium 1,4 endoperoxide (NDPO2). The results show that all the antioxidants tested were inefficient in the system with FeCl3/ascorbate. However, with the other initiating agents, the hydrophilic antioxidant, Trolox, was the most effective in preventing both protein and lipid oxidation. In contrast the lipophilic antioxidants were ineffective in preventing oxidation of BSA in aqueous solution, but did show some moderate antioxidative activity on protein and lipid in the BSA/LnMe system. Using the singlet oxygen generating system it was also demonstrated that Trolox always provided better protection of the protein than tocopherol and the carotenoids in both the BSA and the BSA/LnMe systems. In conclusion, prevention of protein oxidation using a water-soluble antioxidant has a protective effect on the lipid fraction and this approach deserves further attention in complex biological systems.

Energy status, lipid-soluble vitamins, and acute phase proteins in periparturient Holstein and Jersey dairy cows with or without subclinical mastitis

In a retrospective, case-controlled, observational study, associations among indices of negative energy balance, plasma lipid and lipid-soluble vitamin concentrations, plasma acute phase protein status, and occurrence of a new subclinical intramammary infection (IMI) during the periparturient period were determined. Cows were paired based on breed and expected parturition date (EPD) and monitored from the cessation of lactation through wk 8 of the subsequent lactation. A cow was identified as developing a new IMI if the intramammary pathogen isolated postpartum differed from that isolated in wk -9 (relative to EPD). Mean body condition score (BCS) of cows at wk -9 was 3.71 +/- 0.12. Fifteen Holstein and 15 Jersey dairy cows met the study selection criteria. Cows with a new IMI had greater body condition score, body weight, and body weight loss compared with cows that did not develop a new IMI. Prepartum plasma concentrations of beta-carotene were greater for Jersey cows with a new IMI compared with Jersey cows without a new IMI and Holstein cows, regardless of IMI status. However, there was a significant delay in recovery of plasma concentrations of beta-carotene postpartum for Jersey cows with a new IMI compared with Jersey cows without a new IMI. Plasma alpha-tocopherol, albumin, and retinol binding protein concentrations were greater during the periparturient period for cows without a new IMI. Plasma haptoglobin was increased at wk 1 postpartum for cows without a new IMI. Milk protein and lactose percentages and milk urea N were decreased and somatic cell counts were increased in cows identified with a new IMI compared with cows that did not develop a new IMI. Dairy cows with greater tissue energy stores prepartum and reduced plasma proteins, beta-carotene, and alpha-tocopherol had a greater risk for developing a new IMI during the periparturient period.

Betanin inhibits the myeloperoxidase/nitrite-induced oxidation of human low-density lipoproteins

Production of nitrogen dioxide by the activity of myeloperoxidase (MPO) in the presence of nitrite is now considered a key step in the pathophysiology of low-density lipoprotein (LDL) oxidation. This study shows that betanin, a phytochemical of the betalain class, inhibits the production of lipid hydroperoxides in human LDL submitted to a MPO/nitrite-induced oxidation. Kinetic measurements including time-course of particle oxidation and betanin consumption, either in the presence or in the absence of nitrite, suggest that the antioxidant effect is possibly the result of various actions. Betanin scavenges the initiator radical nitrogen dioxide and can also act as a lipoperoxyl radical-scavenger. In addition, unidentified oxidation product(s) of betanin by MPO/nitrite inhibit(s) the MPO/nitrite-induced LDL oxidation as effectively as the parent compound. In the light of betanin bioavailability and post-absorbtion distribution in humans, present findings may suggest favourable in vivo activity of this phytochemical.

Vitamin E therapy prevents hyperoxaluria-induced calcium oxalate crystal deposition in the kidney by improving renal tissue antioxidant status

OBJECTIVE

To determine whether vitamin E prevents hyperoxaluria-induced stone formation, using a new animal model of calcium oxalate stone disease, as our previous in- vitro and in-vivo studies showed that oxalate and hyperoxaluria induce free-radical generation, which results in peroxidative injury to renal tubular cells.

MATERIALS AND METHODS

Ethylene glycol (EG) was administered at 150 mg/day by gavage for 3 weeks to rats fed on diets with adequate (group 1), excess (group 2) or deficient (group 3) vitamin E. Several indicators of peroxidation, free radicals and enzymatic activity were then assessed.

RESULTS

EG treatment in group 1 lead to increased lipid peroxidation, protein thiol, excretion of urinary enzymes, oxalate and decreases in urinary calcium, antioxidant enzymes and altered glutathione redox balance. Although renal function was not altered, there was increased water intake, urine volume and lowered urinary pH in these rats. These changes were more intense, with extensive calcium-oxalate crystal deposition, in rats in group 3, and prevented in rats in group 2, except for urinary oxalate levels, which remained high. Histopathological examination showed that there was no deposition of calcium oxalate crystals in rats in group 2.

CONCLUSION

This is the first study to demonstrate in-vivo evidence that hyperoxaluria-induced peroxidative injury induces individual calcium oxalate crystal attachment in the renal tubules. In addition, excess vitamin E completely prevented calcium oxalate deposition, by preventing peroxidative injury and restoring renal tissue antioxidants and glutathione redox balance. Therefore, vitamin E therapy might provide protection against the deposition of calcium oxalate stones in the kidney of humans.

Circulating markers to assess nutritional therapy in cystic fibrosis

Cystic fibrosis (CF) is the most commonly occurring lethal autosomal recessive disorder. The gene defect causes defective sodium and chloride transport across epithelial cells of the respiratory, hepatobiliary, gastrointestinal and reproductive tracts, resulting in thick mucus secretions. In the respiratory tract, mucus traps bacteria, causing repeated lung infections, progressive bronchiectasis and eventual death due to respiratory failure. In the gastrointestinal tract, mucus prevents pancreatic enzymes reaching the gut, leading to nutrient malabsorption. Careful nutritional management has a dramatic effect on growth and survival rates in CF. Appropriate nutritional support includes pancreatic enzyme replacement therapy, a high-fat/high-energy diet and essential nutrient supplementation, specifically fat-soluble vitamins and essential fatty acids (EFA). Long-term studies are required to examine the effects of nutritional interventions on key clinical outcomes in CF, such as the rate of decline of lung function. The use of circulating markers to assess the influence of nutritional therapy allows short-term intervention studies to predict the potential for clinical improvements. This article provides an overview of the biomarkers useful in the prediction of the efficacy of nutritional therapy on improvements in quality and quantity of life in CF.

Terpenoids as Plant Antioxidants

Plant antioxidants are composed of a broad variety of different substances like ascorbic acid and tocopherols, polyphenolic compounds, or terpenoids. They perform several important functions in plants and humans (e.g., carotenoids function as accessory pigments for light harvesting and provide photoprotection and pigmentation in plants). Monoterpenes and diterpenes, which are the main components of essential oils, act as allelopathic agents, attractants in plant-plant or plant-pathogen/herbivore interactions or repellants. For humans, carotenoids play an important role for health, carotenoids with provitamin A activity are important for vision; other carotenoids influence the human immune function and gap-junctional communication (GJC). Additionally, their antioxidative capacity is believed to be responsible for the health promoting properties of fruits and vegetables. Three main ways of antioxidant action of carotenoids have been detected until now (i.e., quenching of singlet oxygen, hydrogen transfer, or electron transfer). These mechanisms and investigation of antioxidant activity in vitro are discussed in detail. The monoterpenes limonene and perillyl alcohol may be promising substances in cancer therapy. Several investigations have studied the antioxidant activity of monoterpenes and diterpenes or essential oils in vitro. Results as well as the action of a newly discovered, very effective antioxidant (i.e., gamma-terpinene) are discussed. An important point when assessing the antioxidant activity of plant antioxidants is to consider their interaction with other antioxidants. Especially combinations of hydrophilic and lipophilic antioxidants may exert synergistic effects, as has been shown for rutin in combination with gamma-terpinene, lutein, or lycopene.

Determination of pigments in vegetables

Plant pigments are responsible for the shining color of plant tissues. They are also found in animal tissues and, eventually in transformed food products as additives. These pigments have an important impact on the commercial value of products, because the colors establish the first contact with the consumer. In addition plant pigments may have an influence on the health of the consumers. Pigments are labile: they can be easily altered, and even destroyed. Analytical processes have been developed to determine pigment composition. The aim of this paper is to provide a brief overview of these methods.

Effects of beta-carotene on cell viability and antioxidant status of hepatocytes from chronically ethanol-fed rats

The purpose of the present study was to evaluate the effects of beta-carotene on the cell viability and antioxidant status of hepatocytes from chronically ethanol-fed rats. Rats in the ethanol group were given an ethanol-containing liquid diet that provided 36 % of total energy as ethanol, while rats in the control group were fed an isoenergetic diet without ethanol. After 4 weeks, hepatocytes were taken out and cultured for 24 h. Hepatocytes from the rats in the control and ethanol groups were cultured in medium without (HC, HE) or with beta-carotene (HC+B, HE+B). The results showed that lactate dehydrogenase leakage was significantly increased in the HE compared with that in the HC group. However, lactate dehydrogenase leakage of the HE+B group was similar to that of the HC group. When compared with the HC group, activities of glutathione peroxidase and catalase in the HE group were significantly decreased by 54 and 31 %, respectively. Catalase activity in the HE+B group was significantly increased by 61 % compared with that in the HE group. However, activities of glutathione reductase and superoxide dismutase showed no difference among the groups. The level of glutathione in the HC+B and HE+B groups was significantly increased to 155 and 143 % compared with those in the HC and HE groups, respectively. The concentration of lipid peroxides showed no difference among the groups. The present results demonstrate that beta-carotene improved the cell viability of hepatocytes, and increased catalase activities and glutathione levels in hepatocytes from chronically ethanol-fed rats.

Dermal wound healing processes with curcumin incorporated collagen films

The wound healing process involves extensive oxidative stress to the system, which generally inhibits tissue remodeling. In the present study, an improvement in the quality of wound healing was attempted by slow delivery of antioxidants like curcumin from collagen, which also acts as a supportive matrix for the regenerative tissue. Curcumin incorporated collagen matrix (CICM) treated groups were compared with control and collagen treated rats. Biochemical parameters and histological analysis revealed that increased wound reduction, enhanced cell proliferation and efficient free radical scavenging in CICM group. The higher shrinkage temperature of CICM films suggests increased hydrothermal stability when compared to normal collagen films. Spectroscopic studies revealed that curcumin was bound to the collagen without affecting its triple helicity. Further we adopted the antioxidant assay using 2,2'-azobisisobutyronitrile to assess in vitro antioxidant activity of CICM. The antioxidant studies indicated that CICM quenches free radicals more efficiently. This study provides a rationale for the topical application of CICM as a feasible and productive approach to support dermal wound healing.

Antioxidant effect of ferulic acid in isolated membranes and intact cells: synergistic interactions with alpha-tocopherol, beta-carotene, and ascorbic acid

Although an antioxidant mechanism has been involved in the beneficial effects of ferulic acid in human diseases, there are few reports on the antioxidant properties of this compound in isolated membranes and intact cells. Here, we evaluated the ability of ferulic acid in inhibiting lipid peroxidation in rat liver microsomal membranes and reactive oxygen species production in NIH-3T3 fibroblasts, induced by both tert-BOOH and AAPH. We also compared its antioxidant efficiency with that of other antioxidants, such as alpha-tocopherol, beta-carotene, and ascorbic acid, added alone or in combination. Ferulic acid acted as a potent antioxidant in our models, being more effective in protecting from tert-BOOH than from AAPH. Moreover, the compound was the most effective among the antioxidants tested. Synergistic interactions were observed when the compound was used in combination with the other antioxidants, suggesting that they can cooperate in preserving physiological integrity of cells exposed to free radicals.

Five cysteine-containing compounds have antioxidative activity in Balb/cA mice

Balb/cA mice were used to study the in vivo effect of N-acetyl cysteine, S-allyl cysteine, S-ethyl cysteine, S-methyl cysteine and S-propyl cysteine, all derived from garlic, on glutathione (GSH) concentration and catalase and glutathione peroxidase (GPX) activities in plasma, kidney and liver. Cysteine was used for comparison. The effects of these compounds on the levels of fibronectin, triglyceride (TG), cholesterol and alpha-tocopherol were also evaluated. Cysteine or cysteine-containing compounds were added to drinking water at 1 g/L. After 4 wk of treatment, GSH levels in kidney and liver were greater (P<0.05) than in controls. Cysteine decreased catalase and GPX activities in liver, and enhanced both Fe2+- and glucose-induced lipid oxidation in plasma, kidney and liver compared with the control group (P<0.05). However, the administration of the five cysteine-containing compounds enhanced catalase and GPX activities in kidney and liver, and reduced Fe2+- and glucose-induced lipid oxidation in plasma, kidney and liver compared with the control and cysteine-treated groups (P<0.05). Intake of the five cysteine-containing compounds reduced fibronectin, TG and cholesterol concentrations in plasma and liver, and increased the alpha-tocopherol concentration in plasma, kidney and liver compared with the control and cysteine-treated groups (P<0.05). The five cysteine-containing compounds derived from garlic had marked effects on antioxidant enzymes and spared alpha-tocopherol in mice. Furthermore, these compounds reduced fibronectin, TG and cholesterol concentrations in plasma. These data indicate that these compounds have a range of protective effects for cardiovascular disease prevention or therapy.

Vitamin A and infancy. Biochemical, functional, and clinical aspects

Vitamin A is a very intriguing natural compound. The molecule not only has a complex array of physiological functions, but also represents the precursor of promising and powerful new pharmacological agents. Although several aspects of human retinol metabolism, including absorption and tissue delivery, have been clarified, the type and amounts of vitamin A derivatives that are intracellularly produced remain quite elusive. In addition, their precise function and targets still need to be identified. Retinoic acids, undoubtedly, play a major role in explaining activities of retinol, but, recently, a large number of physiological functions have been attributed to different retinoids and to vitamin A itself. One of the primary roles this vitamin plays is in embryogenesis. Almost all steps in organogenesis are controlled by retinoic acids, thus suggesting that retinol is necessary for proper development of embryonic tissues. These considerations point to the dramatic importance of a sufficient intake of vitamin A and explain the consequences if intake of retinol is deficient. However, hypervitaminosis A also has a number of remarkable negative consequences, which, in same cases, could be fatal. Thus, the use of large doses of retinol in the treatment of some human diseases and the use of megavitamin therapy for certain chronic disorders as well as the growing tendency toward vitamin faddism should alert physicians to the possibility of vitamin overdose.

Quercetin incorporated collagen matrices for dermal wound healing processes in rat

We have been developing antioxidants incorporated collagen matrix as a novel biomaterial for various biomedical applications. In this study we made use of quercetin incorporated collagenous matrix for dermal wound healing in rat. Quercetin incorporated collagen (QIC) treated groups were compared with control and collagen (CS) treated animals. QIC treated animal showed a better healing when compared to control and CS treated wound. The biochemical parameters like hydroxyproline, protein, uronic acid content in the healing wound, revealed that there is an increase in proliferation of cells in quercetin treated groups when compared to CS group and there is considerable increase in wound contraction when compared to CS treated group. In addition we adapted the antioxidant assay using 2,2'-azobisisobutryonitrile (AIBN) to assess in vitro antioxidant activity of QIC. The antioxidant studies indicate QIC quench the radicals more efficiently. These results suggested that quercetin incorporated collagen matrix could be a novel dressing material for dermal wound healing.

Design, synthesis, and antioxidant activity of FeAOX-6, a novel agent deriving from a molecular combination of the chromanyl and polyisoprenyl moieties

Several lines of evidence suggest potential benefits by a combination of carotenoids and tocopherols in chronic diseases. Therefore, we have designed FeAOX-6, a novel antioxidant that combines into a single molecule the chroman head of tocopherols and a fragment of lycopene, consisting of a polyisoprenyl sequence of four conjugated double bonds. The ability of FeAOX-6 in inhibiting lipid peroxidation and reactive oxygen species (ROS) production induced by different sources of free radicals (t-BOOH, AAPH, and H2O2) in arachidonic acid solution and in isolated thymocytes was investigated. Its antioxidant efficiency was also compared with that of alpha-tocopherol, lycopene, and a mixture of the two antioxidants. The results strongly suggest that FeAOX-6 can act as a potent antioxidant in our models, by inhibiting malondialdehyde production and ROS generation in a dose- and a time-dependent manner. In the cell model, the compound also provides a higher antioxidant capacity than alpha-tocopherol and lycopene, alone or in combination, suggesting the possibility of an oxidative intramolecular cooperation.

Arachidonate geometrical isomers generated by thiyl radicals: the relationship with trans lipids detected in biological samples

The presence of trans fatty acids in mammalians is attributed to exogenous sources; nevertheless, trans isomers could be easily formed by free radical-catalyzed isomerization processes in vivo. The isomerization of methyl arachidonate (all-cis isomer) catalyzed by thiyl radical is proposed as a methodology applicable in biochemical laboratories, which produces mono- and di-trans isomers. Carbon-13 nuclear magnetic resonance spectroscopy shows that the carbon atom in position 15 is characteristic for each mono- and di-trans isomer. Antioxidants, such as alpha-tocopherol and all-trans-retinol acetate, inhibited the isomerization process. Trans phospholipids are formed in erythrocyte membranes by exposing blood to gamma-irradiation in the presence of thiols, which is in contradiction with the known role of these compounds as radioprotectors. Trans isomers are also analyzed in tissues harvested from breast cancer patients and compared to the adipose breast tissue taken a few centimeters from the edge of the tumor from the same patient. This work is generally aimed at contributing to the debate on trans fatty acids and stimulating a reconsideration of the current view on the exclusive presence of cis double bonds in cell membranes by studying radical processes that could affect or protect this natural configuration.

Action of the novel antioxidants 4GBE43 and 2BBE43 against lipid peroxidation

The action and the effect of the newly synthesized compounds 4GBE43 [N-(1,2-diethyltetrahydro-1H-pyrazol-4-yl)-4-[(2E)-3,7-diethyl-2,6-octadienyl] oxybenzamide] and 2BBE43 [2-(benzyloxy)-N-(1,2-diethyltetrahydro-1H-pyrazol-4-yl)benzamide] against lipid peroxidation were studied. 4GBE43 and 2BBE43 quenched the ESR signal of diphenylpicrylhydrazyl (DPPH), suggesting that 4GBE43 and 2BBE43 act as scavengers of free radicals and that each compound quenched 6 free radical molecules. These compounds suppressed the oxidation of methyl linoleate emulsions and soybean phosphatidylcholine liposomes by a free radical initiator, suggesting that these compounds quench the lipid peroxyl radical. 4GBE43 and 2BBE43 also suppressed the spontaneous oxidation of rat brain homogenates. The inhibitory effect of 2BBE43 was of the same order of magnitude (IC50) as that of probucol. The IC50 of 4GBE43 was on the same order of magnitude as that of alpha-tocopherol. However, 4GBE43 at 10(-4)-10(-5) M completely inhibited peroxidation, showing it to be more effective than alpha-tocopherol. These results suggest that 4GBE43 and 2BBE43 act as antioxidants by quenching the lipid peroxyl radical.

A critical assessment of some biomarker approaches linked with dietary intake

In this review many examples are given of the complexities involved in using some biomarkers in relation to assessing the effects of dietary exposure, when there is frequently a need to determine changes following long-term low level exposure to dietary components. These range from understanding why the biomarker might be valuable and how best it can be measured, to the pitfalls which can occur in the interpretation of data. Analytical technique is considered in relation to folate and selenium, and flavonoid and carotenoid species are used to illustrate how the metabolism of a compound may alter the validity or adequacy of a marker. Vitamin A is discussed in relation to the difficulties which can arise when there are several biomarkers that may be available to assess exposure to one nutrient. Vitamin B12 is discussed in relation to the dietary choices made by individuals. Possible interactions and the role of measuring total antioxidant capacity is considered in some detail. In contrast to most nutrients, there is a marked lack of biomarkers of either exposure or effect for most non-nutrients. The role of biological effect monitoring is considered for dietary contaminants, fumonisins and polyhalogenated aromatic hydrocarbons. Aflatoxins are discussed to exemplify food contaminants for which the biomarker approach has been extensively studied. Finally some compounds which are deliberately added to foods and some which appear as processing contaminants are each considered briefly in relation to the requirement for a biomarker of exposure to be developed.

DNA strand breakage and oxygen tension: effects of beta-carotene, alpha-tocopherol and ascorbic acid

DNA damage is involved in carcinogenesis, aging and other degenerative diseases. The relationship between DNA strand breakage and beta-carotene (0.1-1.6 microM) was examined under different O(2) tensions and with other antioxidants: alpha-tocopherol (5-80 microM), ascorbic acid (10-160 microM) and mixtures of these antioxidants. Supercoiled plasmid DNA pBR322 was incubated with 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) to induce DNA strand breaks in the presence of antioxidants under 15, 150, and 760 torr of O(2) tension. Under 15 torr of O(2) tension, beta-carotene, alpha-tocopherol, ascorbic acid and mixtures of these antioxidants provided a dose-dependent protection against AAPH-induced DNA strand breaks. The best protection was achieved in the mixture of antioxidants. Under 150 torr of oxygen tension, the antioxidant effect of beta-carotene was diminished at > or = 0.8 microM. A prooxidant effect was found at 0.8 > or = microM beta-carotene, producing more single- and double-strand breaks. alpha-Tocopherol and ascorbic acid exhibited dose-dependent antioxidant effects at 150 torr of oxygen tension. Under 760 torr of O(2) tension, the prooxidant effect of 0.8 microM beta-carotene was significant, causing supercoiled DNA to completely breakdown to circular and linear forms. In addition, 760 torr of O(2) tension attenuated the antioxidant effects of alpha-tocopherol and ascorbic acid. Thus, beta-carotene causes concentration-dependent DNA breakdown at high O(2) tension. The protection of DNA from the prooxidant effects of beta-carotene afforded by alpha-tocopherol and/or ascorbic acid was limited at high O(2) tension.

Antioxidant and prooxidant roles for beta-carotene, alpha-tocopherol and ascorbic acid in human lung cells

Experiments were conducted to determine the antioxidant and prooxidant effects of beta-carotene, alpha-tocopherol and ascorbic acid on human lung cells at different oxygen (O(2)) tensions. Free radical initiator, 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH), was used to induce the cellular damage associated with lipid peroxidation, protein oxidation and DNA breaks. Under hypoxic conditions (0 torr O(2) tension) all compounds produced a concentration-dependent antioxidant effect. Mixtures of the three compounds exhibited greater protective affects than any individual compound. At 143 torr O(2) tension, all compounds exhibited concentration-dependent protective effects against AAPH-induced cellular lipid, protein and DNA damage. At 722 torr O(2) tension, cells exhibited a consistent increase in lipid peroxidation (isoprostane formation), protein oxidation (carbonyl formation) and DNA damage (p53 protein accumulation). beta-Carotene (1.5 microM) produced a prooxidant effect by promoting 12% isoprostane formation. Protein oxidation and DNA damage at 722 torr O(2) tension was not increased by beta-carotene; however, the antioxidant effect of beta-carotene was attenuated. The antioxidant effects of alpha-tocopherol, ascorbic acid, and mixtures of the three antioxidant compounds also were reduced by the high O(2) conditions. These results partially substantiate the hypothesis that the antioxidant and prooxidant effects of beta-carotene are dependent on O(2) tension and concentration of beta-carotene. Such findings may partially explain why selected populations, such as smokers, respond adversely when supplemented with beta-carotene.

Determination of synthesized alpha-vitamin E by micellar electrokinetic chromatography

We developed a micellar electrokinetic chromatography method (MEKC) for the direct determination of the content of synthesized alpha-vitamin E. It was found that under the optimum separation conditions 7 mM borate + 14 mM phosphate + 15 mM sodium dodecyl sulfate (SDS) + 10 mM sodium cholate (NaCh) + 8% acetonitrile (pH 9.2) with UV detection wavelength at 214 nm, 16 kV constant voltage, and 26 degrees C constant temperature, alpha-vitamin E and its isomers can be baseline separated and alpha-vitamin E was quantitatively analyzed. In addition, the sample recovery, the limit of detection and the repeatability of the method were investigated. The influence of various parameters on the separation such as SDS concentration, NaCh concentration, buffer pH and acetonitrile percentage were also discussed.

beta-Carotene: interactions with alpha-tocopherol and ascorbic acid in microsomal lipid peroxidation

beta-Carotene, alpha-tocopherol, and ascorbic acid were tested for their ability to inhibit, enhance, or react synergistically with O(2) (15, 150, 760 torr) and, 2,2'-azobis (2-amidino-propane) dihydrochloride (AAPH) or 1,1'-azobis (cyclohexane-carbonitrile) (ACCN) in isolated rat liver microsomes. beta-Carotene did not protect against lipid peroxidation, i.e., malondialdehyde (MDA) formation, in microsomal samples incubated at 37 degrees C with aqueous soluble AAPH at all added beta-carotene concentrations and oxygen tensions. More MDA (16%, p < 0.001) was produced at 15 torr of O(2,) and 160 nmol/mg protein of beta-carotene compared to respective vehicle control. Individually, alpha-tocopherol and ascorbic acid exhibited antioxidant protection (ascorbic acid &z.Gt; alpha-tocopherol); however, a mixture of both compounds was no more protective than ascorbic acid alone. beta-Carotene demonstrated a concentration-dependent antioxidant affect at 15 torr O(2) (p < 0.01); but a prooxidant effect at higher O(2) at 150 and 760 torr (>57%, p < 0.001) by lipid-soluble ACCN. alpha-Tocopherol exhibited concentration-dependent inhibitory effects on microsomal MDA formation at all oxygen tensions, but was most effective under 150 torr. Ascorbic acid demonstrated a concentration-dependent antioxidant effect only at 150 torr. ACCN-induced lipid peroxidation was no greater for the combination of the three compounds than ascorbic acid added alone. Thus, antioxidant or prooxidant activities for beta-carotene, alpha-tocopherol, and ascorbic acid in microsomal suspensions are related to O(2) tension, solubility, antioxidant concentrations and are governed by complex interactions. Differences between AAPH- and ACCN-induced lipid peroxidation are related to differences in lipid solubility.

Long-term oral beta-carotene supplementation in patients with cystic fibrosis - effects on antioxidative status and pulmonary function

To investigate the efficacy of long-term oral beta-carotene supplementation for optimizing the antioxidant status and pulmonary function in patients with cystic fibrosis (CF), 24 patients (aged 12. 8 +/- 6.3 years) were randomized to a CF supplementation or to a CF placebo group. As controls 14 healthy age-matched subjects (aged 14. 7 +/- 6.2 years) were studied. Patients of the CF supplementation group received 1 mg beta-carotene/kg body weight (BW)/day (maximally 50 mg beta-carotene/day) for the first 12 weeks; during the following 12 weeks, dosage was reduced to 10 mg beta-carotene/day. At study entry, plasma beta-carotene concentrations were significantly lower in CF patients than in controls (p < 0.001). In the CF supplementation group, plasma beta-carotene concentrations were significantly increased (baseline: 0.08 +/- 0.04 micromol/l) at the end of high-dose treatment (12th week; 0.6 +/- 0.4 micromol/l; p < 0.001), but decreased again during supplementation with 10 mg beta-carotene/day to 0.3 +/- 0.2 micromol/l at the end of the study (p < 0.001). beta-Carotene supplementation did not affect plasma concentrations of other carotenoids and retinol, but an increase in plasma alpha- and gamma-tocopherol concentrations was noticed. During high-dose treatment, a significant decrease in TBA-MDA complexes and a correction of total antioxidative capacity was observed. During the treatment, pulmonary exacerbation could be corrected significantly (p < 0.05). We conclude that CF patients can be efficiently supplemented with 1 mg beta-carotene/kg BW/day (maximally 50 mg beta-carotene/day) to achieve plasma concentrations of healthy control subjects and to minimize oxidative stress, improving the quality of life of CF patients.

Beta-carotene and protein oxidation: effects of ascorbic acid and alpha-tocopherol

The effect of beta-carotene on protein oxidation was examined under different oxygen (O(2)) tensions and with other antioxidants: alpha-tocopherol, ascorbic acid, and mixtures of antioxidants. Human serum albumin (HSA) was incubated with 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) to induce protein oxidation (carbonyl formation), under 15, 150, and 760 torr of O(2) tension. Antioxidant activity was related to O(2) tension, antioxidant concentrations and interaction between mixtures of antioxidants: (1) Under 15 torr of O(2), incubating HSA with AAPH, 1. 6 microM beta-carotene, 80 microM alpha-tocopherol, 160 microM ascorbic acid, and mixtures (0.1 microM beta-carotene, 5.0 microM alpha-tocopherol and 10 microM ascorbic acid) resulted in 24, 29, 39, and 44% reduction of carbonyl formation, respectively. (2) Under 150 torr of O(2) tension, the antioxidant effect of beta-carotene was decreased by 4% but increasing O(2) tension did not diminish the antioxidant effects of alpha-tocopherol, ascorbic acid, or antioxidant mixtures. (3). Under 760 torr of O(2) tension, adding 1. 6 microM beta-carotene resulted in 26% more carbonyl formation. (4) Under 760 torr of O(2) tension, the antioxidant effect of ascorbic acid was decreased 32% compared to what was observed at 150 torr of O(2) tension. Changes in O(2) tension had no effect on the antioxidant effect of alpha-tocopherol. The mixture of antioxidants inhibited carbonyl formation by 37% and was 7% less effective than that of 15 and 150 torr of O(2) tension. High concentration of beta-carotene produces more protein oxidation in the presence of high O(2) tension by a prooxidant mechanism. Mixtures of beta-carotene, alpha-tocopherol, and ascorbic acid provided better protective effects on protein oxidation than any single compound.

Exogenously incorporated ketocarotenoids in large unilamellar vesicles. Protective activity against peroxidation

The ability of astaxanthin and canthaxanthin as chain-breaking antioxidants was studied in Cu(2+)-initiated peroxidation of phosphatidylcholine large unilamellar vesicles (LUVs). Both carotenoids increased the lag period that precedes the maximum rate of lipid peroxidation, though astaxanthin showed stronger activity. For these experiments, different amounts of xanthophylls were exogenously added to previously made LUVs, non-incorporated pigment being afterwards removed. Differential scanning calorimetry assays with L-beta,gamma-dimyristoyl-alpha-phosphatidylcholine LUVs demonstrated that xanthophylls incorporated as described interact with the lipid matrix becoming interspersed among the phospholipid molecules.

Beta-carotene antagonizes the effects of eicosapentaenoic acid on cell growth and lipid peroxidation in WiDr adenocarcinoma cells

The effects of combinations between eicosapentaenoic acid (EPA) and beta-carotene on cell growth and lipid peroxidation were investigated in human WiDr colon adenocarcinoma cells. EPA alone was able to inhibit the growth of WiDr cells in a dose- and time-dependent manner. Such an inhibition involved fatty acid peroxidation, as shown by the remarkable increase in the levels of Malondialdehyde (MDA) in EPA-treated cells. Beta-carotene was capable of reducing the growth inhibitory effects of EPA and the levels of MDA in a dose- and a time-dependent manner. In addition, EPA increased beta-carotene consumption in WiDr cells. This study provides evidence that beta-carotene can antagonize the effects of EPA on colon cancer cell growth and lipid peroxidation.