Radical-induced Lipid Peroxidation Research Articles

Intracellular distribution of bis-allylic deuterated linoleic acid into the lipidome of human keratinocytes

Polyunsaturated fatty acids (PUFA) are particularly susceptible to free radical-induced lipid peroxidation (LPO). Specific deuteration at bis-allylic positions of PUFA (D-PUFA) has been recently proposed as a way to inhibit the LPO. Here, a high mass resolution untargeted lipidomic analysis protocol was applied to examine the changes in the lipidome of keratinocytes supplemented with bis-allylic deuterated linoleic acid (D2-LA). Incorporation of D2-LA occurs preferentially in membrane phospholipids such as phosphatidylcholine and phosphatidylethanolamine, followed by triglycerides. However, the relative contribution of D2-LA among membrane lipids is highest in cardiolipin (60%) followed by its precursor phosphatidylglycerol (50%). Cardiolipins are enriched in PUFA and exclusively located in mitochondrial membranes, thus representing major targets for lipid peroxidation. These findings indicate that D2-LA supplementation is linked to the preservation of mitochondrial function under oxidative stress. Finally, our study highlights the suitability of high mass resolution lipidomic analysis to investigate lipid metabolism at the level of individual molecular species in stable isotope tracing experiments.

Carbon Dots from Paeoniae Radix Alba Carbonisata: Hepatoprotective Effect.

IntroductionThe charcoal processed product of Paeoniae Radix Alba (PRA), PRA Carbonisata (PRAC), has long been used for its hepatoprotective effects. However, the material basis and mechanism of action of PRAC remain unclear.AimTo explore the hepatoprotective effects of Paeoniae Radix Alba Carbonisata-derived carbon dots (PRAC-CDs).MethodsPRAC-CDs were characterized using transmission electron microscopy, high-resolution transmission electron microscopy, ultraviolet, fluorescence, Fourier transform infrared and X-ray photoelectron spectroscopy, X-ray diffraction, and high-performance liquid chromatography. The hepatoprotective effect of PRAC-CDs was evaluated and confirmed using the classic carbon tetrachloride acute liver injury model.ResultsPRAC-CDs averaged 1.0–2.4 nm in size and exhibited a quantum yield of 5.34% at a maximum excitation wavelength of 320 nm and emission at 411 nm. PRAC-CDs can reduce the ALT and AST levels of mice with carbon tetrachloride-induced acute liver injury and have a mitigating effect on the rise in TBA and TBIL. More interestingly, PRAC-CDs can significantly reduce MDA and increase SOD levels, demonstrating that PRAC-CDs can improve the body’s ability to scavenge oxygen free radicals and inhibit free radical-induced liver cell lipid peroxidation, thereby preventing liver cell damage.ConclusionThese results demonstrate the remarkable hepatoprotective effects of PRAC-CDs against carbon tetrachloride-induced acute liver injury, which provide new insights into potential biomedical and healthcare applications of CDs.

QuitPuff: A simple method using lipid peroxidative changes in saliva to assess the risk of oral precancerous lesions and oral squamous cell carcinoma in chronic smokers

Abstract Introduction: Smoking, the leading cause of oral cancer in India, kills over 5 people every hour. As high mortality is due to late diagnosis, early detection is vital. Free radical-induced lipid peroxidation (LP) is known to promote multistep oral carcinogenesis. Free radicals generated by smoking damage polyunsaturated fatty acids releasing end product malondialdehyde (MDA). A simple, home-based test was devised to determine salivary MDA to assess early risk of oral precancer and cancer. It was hypothesized that heavier smokers would exhibit greater degree of salivary LP. Materials and Methods: A highly sensitive QuitPuff reagent was formulated which when heated with saliva, produces a color change, directly proportional to the amount of MDA. The MDA level was measured by matching the color change with a colorimetric LP index (LPI) chart. QuitPuff was tested on 500 subjects, validated using the gold standard, ultraviolet (UV) spectroscopy. Results: The mean LPI was consistently and significantly elevated (P < 0.001) in smokers with oral precancer and cancer (4.34) and smokers who smoked more than 20 (4.12), between 10 and 20 (3.43), and <10 cigarettes per day (2.43) as compared to nonsmokers (0.26). The mean LPIs of the test and validation methods correlated. Spearman's correlation indicated significant positive association between color changes and UV spectroscopy readings (r = 0.93). QuitPuff detected salivary MDA levels with 96% accuracy. Conclusion: Smokers exhibited greater degree of salivary LP as compared to nonsmokers; the heavier the smoker, greater was the degree of LP. QuitPuff has great potential as a point-of-care test for oral precancer and cancer.

Syringic and cinnamic acids antiradical/antioxidant activities as R. ferruginea extract components and membrane physico-chemical influence

Syringic and cinnamic acids were previously identified as the major components on Rapanea ferruginea′s leaf extract. In this work, these phenolic acids were investigated and correlated in two aspects. The first one was referred to their role against DPPH and hydroxyl radicals, considering the concentration detected in R. ferruginea extract. The second one considered their effects on the physico-chemical properties of soy asolectin liposomes, such as hydration degree, trans-gauche isomerization, vibrational, rotational and translational motions, state-of-phase, size and surface charge. The half-maximum inhibitory concentration (IC50) related to syringic acid in DPPH assays was detected as 7.36 × 10−3 mM. At the cinnamic acid highest tested concentration (8.23 × 10−3 mM), the activity against DPPH was around 4.6%. Regarding hydroxyl radical-induced lipid peroxidation, the IC50 detected for syringic acid free in solution (free-form) was equivalent to 0.082 × 10−3 mM, a value 3.6 times lower than the detected for its liposome-loaded form. At the highest tested concentration (0.24 × 10−3 mM), the free-form cinnamic acid inhibited lipid peroxidation by 4 times the observed to its liposome-loaded form. Results showed that hydrogen donation is not the preferential mechanism in which the tested phenolic acids inhibit hydroxyl radical-induced lipid peroxidation. Syringic acid showed higher antioxidant potential than cinnamic acid, probably having a primordial role in the properties related to R. ferruginea. Liposomes’ physico-chemical data provided correlations between the phenolic acids’ antioxidant potential and their influence in the mobility of specific lipid groups. The findings of this work will contribute to the design and development of phenolic acids-based and plant extract-based pharmacological systems.

Myeloperoxidase-mediated oxidation of edaravone produces an apparent non-toxic free radical metabolite and modulates hydrogen peroxide-mediated cytotoxicity in HL-60 cells

Edaravone is considered to be a potent antioxidant drug known to scavenge free radical species and prevent free radical-induced lipid peroxidation. In this study, we investigated the effect of edaravone on the myeloperoxidase (MPO) activity, an enzyme responsible for the production of an array of neutrophil-derived oxidants that can cause cellular damage. The addition of edaravone to the reaction of MPO and hydrogen peroxide (H2O2) significantly enhanced the reduction of MPO Compound II back to native MPO. Interestingly, the MPO-mediated production of toxic hypochlorous acid exhibited a concentration-dependent biphasic effect, with the apparent optimal edaravone concentration at 10 μM. Oxidation of edaravone by MPO was examined by various analytical methods. An MPO-catalyzed product(s) of edaravone was identified at 350 nm by kinetic analysis of UV–Vis spectroscopy. Several MPO-catalyzed metabolites of edaravone were proposed from the LC-MS analyses, including oxidized dimers from edaravone radicals. Electron spin resonance (ESR) spin trapping detected a carbon-centred radical metabolite of edaravone. NMR studies revealed that there are two exchangeable hydrogens, one of which is on the α-carbon, justifying the carbon-centred edaravone radical produced from MPO. Despite the formation of an edaravone carbon-radical metabolite, it did not appear to effectively oxidize GSH (in comparison with phenoxyl radicals). Viability (ATP) and cytotoxicity (LDH release) assays showed a concentration-dependent effect of edaravone on HL-60 cells treated with either a bolus concentration of 30 μM H2O2 or a flux of H2O2 generated by 5 mM glucose and 10 mU/mL glucose oxidase. The H2O2-induced toxicity was ameliorated at high edaravone concentrations (100–200 μM). In contrast, low concentrations of edaravone (1–10 μM) exacerbated the H2O2-induced toxicity. However, the effect of edaravone at low concentration (0–10 μM) appeared more prominent with the LDH assay only. The cellular findings correlated with the biochemical studies with respect to hypochlorous acid formation. These findings provide interesting perspectives regarding the duality of edaravone as an antioxidant drug.

Repeatedly heated cooking oils induced alterations in erythrocyte membrane integrity and antioxidant status in cholesterol fed Sprague Dawley rats

Repeatedly heated cooking oils induce oxidative stress in animals. Erythrocytes are prone to free radical induced lipid peroxidation. This study compared the effects of repeatedly heated cooking oils on erythrocyte membrane changes in hypercholesterolemic rats. Coconut oil, mustard oil, and sunflower oil were heated at 210 ± 10°C for 15 hr. Fresh/heated oils (15%) and cholesterol (1%) were fed with experimental diet for 60 days. Chemical analysis showed deteriorative changes in heated oils, effect being lower in heated coconut oil. Elevated MDA and protein carbonyl content and compromised antioxidant status was observed in heated oil fed animals. Membrane bound enzymes were decreased and markers of in vivo hemolysis were significantly elevated in heated oil fed animals. Osmotic fragility of erythrocytes was also higher in heated oils fed groups. Our study shows increased lipid peroxidation associated with reduced antioxidant status of erythrocytes, make them more susceptible to hemolysis. Practical applications High fat and cholesterol are increasingly being included in the modern diet. Hypercholesterolemia and lipid oxidation are serious risk factors contributing to the pathogenesis of atherosclerosis. Thermally treated dietary fats in typical modern diets contain lipid peroxidation products. Cooking oils are repeatedly heated at high temperatures and reused for maximum profit during various food preparations. The nature of fatty acids influences the rate of lipid peroxidation occurring in oils during thermal treatments. The present study clearly showed that frying oils such as mustard oil and sunflower oil have lower stability than coconut oil because of high polyunsaturated fatty acid content. Results obtained from these investigations indicate that consumption of thermally oxidized cooking oil causes oxidative damage thereby increasing the risk of atherosclerosis. Hence for optimal use, it is necessary to distinguish the quality of oil and not to expose cooking oils to high temperatures for longer duration.

The influence of antioxidants in the thiyl radical induced lipid peroxidation and geometrical isomerization in micelles of linoleic acid

The biomimetic model of micelles of linoleic acid containing 2-mercaptoethanol and the antioxidant was examined under gamma irradiation up to 400 Gy in aerobic or deoxygenated conditions where thiyl radicals are the main reactive species. Lipid peroxidation was retarded by ascorbic acid and α-tocopherol, whereas this process was strongly inhibited by resveratrol as effectively as the ascorbic acid/α-tocopherol mixture. Furthermore, antioxidants have a much stronger inhibitory effect on the peroxidation in the presence of 2-mercaptoethanol, and at the same time show protective properties of the double bond, decreasing the cis–trans isomerization. Under anaerobic conditions, cis–trans isomerization occurred and antioxidants efficiency increased along the series: resveratrol < α-tocopherol < ascorbic acid. This result is explained taking into account the double bond localization in the hydrophobic core of the micelle and the need of co-localization of the antioxidant in order to get an anti-isomerizing activity and protection of the natural lipid geometry.

Chronic Hypobaric Hypoxia Induces Right Ventricular Hypertrophy and Apoptosis in Rats: Therapeutic Potential of Nanocurcumin in Improving Adaptation.

Nehra, Sarita, Varun Bhardwaj, Santosh Kar, and Deepika Saraswat. Chronic hypobaric hypoxia induces right ventricular hypertrophy and apoptosis in rats: therapeutic potential of nanocurcumin in improving adaptation. High Alt Med Biol. 17:342-352, 2016.-a sustained work load on the right heart on ascent to high altitudes promotes right ventricular hypertrophy (RVH), which eventually undergoes decompensation and promotes pathological damage. However, the exact set of events leading to damage remains unidentified. Curcumin is a natural antioxidant and antihypertrophic agent, but it has poor biostability. Nanotized curcumin (nanocurcumin) has emerged as a promising agent with improved biostability while retaining the therapeutic properties of curcumin. The present study aimed at analyzing the therapeutic properties of nanocurcumin in ameliorating cardiac damage due to chronic hypobaric hypoxia (HH)-induced RVH in comparison to curcumin. Sprague-Dawley rats exposed to HH (25,000 feet, effective oxygen fraction in air [FIO2] ∼0.08, temperature 28°C ± 1°C, relative humidity 55% ± 2% for 3, 7, 14, and 21 days) developed RVH with increased interstitial collagen content, Fulton's index, and cardiomyocyte cross-sectional area while upregulating atrial natriuretic peptide. Tissue damage due to apoptotic cell death was evident by cytochrome-c/caspase-3 activation and TUNEL assay. Concomitant modulation of cyclic guanosine monophosphate (cGMP)/cGK-1, calmodulin-dependent protein kinase II (CaMkinase II), and intracellular calcium levels with increased free radical-induced damage and lipid peroxidation further contributed to the right heart pathology. Nanocurcumin supplementation decreased HH-induced RVH and apoptosis while modulating cardiac cGMP/cGK-1 signaling, and maintaining CaMkinase II, intracellular calcium levels and redox status better than curcumin. Nanocurcumin-mediated antiapoptotic effects might have benefited residents and sojourners at high altitude in preventing hypoxic cardiac damage.

Hepatoprotective and antioxidant efficacy of aqueous stem bark extracts of Balanites aegyptiaca (Linn.) Del. against acetaminophen induced liver injury in rats

Traditional use of various extracts of Balanites aegyptiaca in the management of many diseases has been previously reported. Though oxidative stress is known to contribute to the development of many of the disease conditions on which extracts of B. aegytiaca have been found efficacious, effects of these extracts on free radical-induced lipid peroxidation is not well understood. This study investigated the protective effects of stem bark extracts of B. aegyptiaca on acetaminophen-induced lipid peroxidation in rats. Phytochemical analysis of the plant extract used was conducted. Following a 10 day pre-treatment with extracts of B. aegyptiaca, serum levels of thiobarbituric reactive substances (TBARS), vitamin C, cholesterol/phospholipids, catalase (CAT) activity as well as markers enzymes of hepatotoxicity were measured in rats administered with acetaminophen (2 mg/kg body weight). Results obtained indicated preponderance of alkaloids, flavonoids, glycosides, phenols, saponins, and tannins. Pre-treatment with extracts of B. aegyptiaca protected against acetaminophen-induced elevation of TBARS and marker enzymes of hepatotoxicity as well as inhibited the depletion of serum levels of vitamin C, CAT activity and phospholipids in a dose-dependent manner. Serum levels of cholesterol were not affected by acetaminophen intoxication or treatment with the plant extract. These results indicated that therapeutic actions previously linked with extracts of B. aegyptiaca might be a consequence of its antioxidative and hepatoprotective effects.

A neuronal aging pattern unique to humans and common chimpanzees

Lipofuscin pigment accumulation is among the most prominent markers of cellular aging in postmitotic cells. The formation of lipofuscin is related to oxidative enzymatic activity and free radical-induced lipid peroxidation. In various mammals such as rat, dog, macaque as well as in cheirogaleid primates, most of the large neurons, such as cerebellar Purkinje cells and neocortical pyramidal cells, show heavy lipofuscin accumulation in adulthood. In contrast, a well-known yet poorly studied feature of the aging human brain is that although lipofuscin accumulation is most marked in large neurons of the cerebral cortex, the large neurons of the cerebellar cortex-the Purkinje cells-appear to remain free of lipofuscin accumulation. It is however, not known whether this characteristic of human Purkinje cells is shared with other primates or other mammals. This study reports results from histological observation of Purkinje cells in humans, non-human primates, and other mammals. Procedures include histochemistry, immunocytochemistry, and fluorescence microscopy. Abundant lipofuscin deposition was observed in Purkinje cells of all the species we examined except Homo sapiens (including Alzheimer's disease cases) and Pan troglodytes. In contrast, lipofuscin deposition was observed in neurons of the dentate nucleus. Our findings suggest that when compared with other primates, Purkinje cells in chimpanzees and humans might share a common aging pattern that involves mechanisms for neuroprotection. This observation is important when considering animal models of aging.

Protection of Clitoria ternatea flower petal extract against free radical-induced hemolysis and oxidative damage in canine erythrocytes

The present study assessed the antioxidant activity and protective ability of Clitoria ternatea flower petal extract (CTE) against in vitro 2,2′-azobis-2-methyl-propanimidamide dihydrochloride (AAPH)-induced hemolysis and oxidative damage of canine erythrocytes. From the phytochemical analysis, CTE contained phenolic compounds, flavonoids, and anthocyanins. In addition, CTE showed antioxidant activity as measured by oxygen radical absorbance capacity (ORAC) method and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. CTE (400 µg/ml) remarkably protected erythrocytes against AAPH-induced hemolysis at 4 h of incubation. Moreover, CTE (400 µg/ml) reduced membrane lipid peroxidation and protein carbonyl group formation and prevented the reduction of glutathione concentration in AAPH-induced oxidation of erythrocytes. The AAPH-induced morphological alteration of erythrocytes from a smooth discoid to an echinocytic form was effectively protected by CTE. The present results contribute important insights that CTE may have the potential to act as a natural antioxidant to prevent free radical-induced hemolysis, protein oxidation and lipid peroxidation in erythrocytes.

Selenium contents in Korean snack and dairy products (826.1)

Se is a trace micro‐mineral and antioxidant protecting human body from the free radical induced lipid peroxidation. However, there are little reports on the Se intake status of Koreans because of deficient Se database on foods. Furthermore, the accuracy of existing data is questionable because they were usually analysed using methods as pre‐treatment process such as wet digestion or dry digestion, which can cause selenium loss. This study was aimed to evaluate Se contents in edible portion of snack and dairy products by instrumental activation analysis(=INAA) method using freeze‐drying as a pre‐treatment process. The most frequently consumed snacks and dairy products by Korean were selected for the analysis of Se contents. To minimize contamination, all the instruments and storage tools were used after washing with HNO3. Each food samples were individually mixed using homogenizer equipped with titanium blade. The homogenized food samples of 10~20g were freeze‐dried at temperature of ‐60 C for 24~96 h and subsequently, used to analyze Se contents by IINAA‐method. Analytical quality control was conducted using NIST SRMs. The analysis limit of Se in foods by INAA was 0.01ppm. Se contents in processed foods were in the range of 0.22ug~14.9ug in 100g foods. The Se contents were various according to the type of processed foods. The average Se contents in 100g sandwich, snack, milk, soy milk, joghurt were presented. This result will be useful in establishing the food Se database for Koreans.Grant Funding Source: Korean Research Foundation

Distinct Types of Lipofuscin Pigment in the Hippocampus and Cerebellum of Aged Cheirogaleid Primates

The formation of autofluorescent lipopigment or lipofuscin is a highly consistent and reliable cytological change that correlates with cellular aging in postmitotic cells. One causal factor of lipofuscinogenesis involves free radical-induced lipid peroxidation. In mammals, dentate gyrus neurons and Purkinje cells are usually affected widely. In this study, we investigated the ultrastructure of lipofuscin deposits in large neurons of the dentate gyrus and in Purkinje cells of aged fat-tailed dwarf lemurs (Cheirogaleus medius Geoffroy, 1812) with electron and confocal microscopy and compared it with previous observations in other species. Cheirogaleid primates such as mouse and dwarf lemurs are archaic primates that provide interesting nonhuman models of aging. Our study revealed region-specific as well as species-specific characteristics of lipofuscin ultrastructure. This suggests differences in cellular metabolism and/or in organelles involved in lipofuscin production in cerebellar Purkinje cells and in hippocampal dentate gyrus neurons.

Analysis of Se contents in Korean processed foods according to food type

Selenium is an essential micro‐mineral and antioxidant protecting from the free radical induced lipid peroxidation. However, there are little reports on the Se nutritional status of Koreans because of deficient Se database on foods. This study was aimed to evaluate Se contents in edible portion of processed foods using instrumental activation analysis (=INAA) method, which cause little Se loss during pre‐treatment. The most frequently consumed processed foods by Korean were selected for the analysis of Se contents. Each food samples were individually mixed using homogenizer made with titanium. The homogenized food samples of 10~20g were freeze‐dried at temperature of −60 C for 24~96 h and subsequently, used to analyze Se contents by INAA‐method. Analytical quality control was conducted using NIST SRMs. The analysis limit of Se in foods by INAA was 0.01ppm. Se contents in processed foods ranged from 0.22ug to 14.9ug in 100g foods. The selenium contents were various according to the type of processed foods. The mean Se contents in 100g Ramen, which is one of the most consumed foods among Koran people, was in 8.6ug. The selenium contents were 8.4ug, 6.4ug, 1.4ug in 100g cold noddle, wonton and instant coffee mixture, respectively. This result will be useful in establishing the food Se database for Koreans.Grant Funding Source: National Reserch Foundtion of Korea

Antioxidative Action of Citrus limonum Essential Oil on Skin

Aims: The purpose of this study was to investigate the action of Citrus limonum essential oil to control free radical-induced lipid peroxidation and preventing tissue damage in skin. Place and Duration of Study: Department of Internal Medicine (University of Roma “Tor Vergata) and A.R.P.A (Aging Research, Prevention and Therapy Association, www.antiaging.it), between January 2010 and June 2011. Methodology: The essential oil was subjected to GC-MS analysis. The superoxide anion scavenging activity of essential oil was evaluated by the enzymatic hypoxanthine/xanthine oxidase system. The same oil diluted in DMSO or grape-seed oil was spread on the face of human volunteers after UV exposition. A sample of skin lipids was collected and the presence of peroxyl radicals was detected based on the measurement of light emitted (chemiluminescence) when the excited carbonyl and singlet oxygen decay to ground state. Research Article European Journal of Medicinal Plants, 3(1): 1-9, 2013 2 Results: Our data demonstrate that the lemon essential oil is more active than tocopherol against O2 and peroxide free radical inhibition at 1:100 dilution. A protocol for controlling free radical-induced lipid peroxidation in human skin was thus proposed. Conclusion: The scavenging action of lemon essential oil could have a practical application for treating human skin against oxidative damage.

Partial characterization, in vitro antioxidant and antiproliferative activities of patatin purified from potato fruit juice

Patatin from potato fruit juice was purified by a combination of ultrafiltration and chromatographic techniques. The in vitro antioxidant and antiproliferative activity against mouse melanoma B16 cells of patatin were investigated. The results showed that the monosaccharide composition of patatin included rhamnose, mannose, glucose, and galactose with a molar ratio of 41 : 30 : 21 : 8, and patatin consisted of (1 → 3) linked α-mannose, (1 → 4) linked α-galactose, (1 → 4) linked β-glucose, and (1 → 2) linked α-rhamnose. Furthermore, patatin possessed significant antioxidant activities measured by scavenging of the DPPH and superoxide free radicals, notable reducing power, protective effects against hydroxyl radical-induced oxidative DNA damage and lipid peroxidation inhibitory. Moreover, patatin was identified as a potent antiproliferative agent against mouse melanoma B16 cells, causing cell cycle arrest in the G1 phase. Assays of apoptotic cells also showed that patatin treatment at concentrations of 20 mg mL(-1) resulted in a marked reduction of viable cells. These results obtained in in vitro models suggested that patatin may have potential application as a cancer chemopreventive agent and food ingredient.

The influence of antioxidants in the thiyl radical induced lipid peroxidation and isomerization processes in linoleic acid micelles

Lipids are targets of various reactive oxygen, nitrogen and sulphur species. There are two main classes of reactions that are known in the context of reactivity of polyunsaturated fatty acids toward free radicals. One of the well known process is lipid peroxidation and the second one, much recent studied, is the process of geometrical isomerization of unsaturated lipids which can be catalysed by thiyl radicals (RS•). It has been shown that one process can be parallel with the occurence of the other and that lipid hydroperoxides and trans lipids can be the resulting effect of oxidative free radical conditions. In living organizms both lipid peroxidation and isomerization have damaging effects on cell membranes. The study of these processes in the biomimetic model of micelles of linoleic acid (LH) containing 2-mercaptoethanol as the thiol, has been extended in the presence of several natural occuring antioxidants. In order to study their protective properties against lipid peroxidation and trans isomerization, each of antioxidants -tocopherol, ascorbic acid and resveratrol, was added to the model systems. The systems were irradiated by gamma radiation up to 400 Gy, under a variety of conditions where RS• are the main reactive species. Preliminary results have shown that lipid peroxidation was retarded by ascorbic acid and -tocopherol, whereas this process was strongly inhibited by resveratrol. Furthermore, antioxidants have a much stronger inhibitory effect on the peroxidation in the presence of 2-mercaptoethanol. In model systems under anaerobic conditions, where process of geometrical isomerization prevails, the presence of antioxidants have influenced on decrease of the trans isomerization level. The ability of RS• scavenging was found to increase along the series resveratrol, -tocopherol, ascorbic acid. All results obtained in this study indicate that trans isomerization depends on the localization of the particular antioxidant in model LH system.

Plasma Levels of Oxidative Stress Biomarkers and Long‐Term Cognitive Performance after Severe Head Injury

Plasma Levels of Oxidative Stress Biomarkers and Long‐Term Cognitive Performance after Severe Head Injury

Inhibition of lipid peroxidation and protein oxidation by endogenous and exogenous antioxidants in rat brain microsomes in vitro

Reactive oxygen and reactive nitrogen species oxidize and nitrate DNA, lipid and proteins thus leading to neuronal death. Both endogenous and dietary antioxidants were shown to afford neuroprotection either by scavenging free radicals or inducing antioxidant enzymes. That said, the differential contribution of endogenous versus nutritional antioxidants to prevent neurodegeneration is still debated. In this study the free radical scavenging activity of two endogenous antioxidants, such as bilirubin and its precursor biliverdin, was compared with that of the dietary antioxidant alpha-tocopherol in rat brain microsomes exposed to peroxyl radical or peroxynitrite in vitro. Bilirubin and biliverdin (1–200μM) inhibited both peroxyl radical- and peroxynitrite-dependent lipid peroxidation with a greater potency and efficacy than alpha-tocopherol. However, both BV and BR displayed greater potency and efficacy in preventing peroxynitrite- than peroxyl radical-induced lipid peroxidation. The greater antioxidant effect of both bilirubin and biliverdin than alpha-tocopherol was also confirmed against peroxyl radical- and peroxynitrite-induced protein oxidation. In conclusion, both bilirubin and biliverdin exhibited a greater antioxidant activity than alpha-tocopherol in preventing oxidative stress damage in rat brain.

3,4,4′-Trihydroxy-trans-stilbene, an analogue of resveratrol, is a potent antioxidant and cytotoxic agent

Resveratrol (3,5,4′-trihydroxy-trans-stilbene) is a naturally occurring polyphenol widely distributed in food and dietary plants. This phytochemical has been intensively studied as an efficient antioxidant and anticancer agent, and a variety of substituted stilbenes have been developed in order to improve the potency of resveratrol. In this work, we described the synthesis of 3,4,4 -trihydroxy-trans-stilbene (3,4,4′-THS), an analogue of resveratrol, and studied its antioxidant and cytotoxic activity in vitro. 3,4,4 -THS was much more efficient than resveratrol in protecting against free radical-induced lipid peroxidation, photo-sensitized DNA oxidative damage, and free radical-induced hemolysis of human red blood cells. More potent growth inhibition in cultured human leukemia cells (HL-60) was also observed for 3,4,4 -THS. The relationship between the antioxidant efficiency and cytotoxic activity was discussed, with the emphasis on inhibition of the free radical enzyme ribonucleotide reductase by antioxidants. The result that this subtle structure modification of resveratrol drastically improves its bioactivity provides important strategy to develop novel resveratrol-based molecules.