Antioxidant effects of extra virgin olive oil enriched by myrtle phenolic extracts on iron-mediated lipid peroxidation under intestinal conditions model.

Chelating and free radicals scavenging activities of extra virgin olive oil (EVOO) enriched by Myrtus communis phenolic compounds (McPCs), α-tocopherol and Butylated hydroxytoluene (BHT) were evaluated using chemical assays, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Oxygen radical absorbance capacity (ORAC), and biological model as 2,2'-azobis (2-aminopropane) dihydrochloride (AAPH) or Fe+3/Ascorbic acid (Fe+3/AsA) system mediated peroxidation of l-α-phosphatidylcholine aqueous dispersions stabilized by bile salts (BS) under simulated intestinal conditions (pH 7.4). McPC-EEVOO increased significantly the neutralization of DPPH radical and AAPH-derived radicals in ORAC assay more than α-tocopherol and BHT. The phospholipid stability increased by a factor of 33.6%, 34.8%, 19.3% and 10.7% for myrtle microwave assisted extraction (MAE) and conventional extraction (CE) extracts, α-tocopherol and BHT, respectively, as compared to the control (EVOO without enrichment) in Fe+3/AsA system. But a slightly additive effect was observed when AAPH system was used. Our observation showed that McPCs may interact positively with EVOO to inhibit phospholipid peroxidation, and thus, McPC-EEVOO could be a potential functional food.

Antioxidative properties and ability of phenolic compounds of Myrtus communis leaves to counteract in vitro LDL and phospholipid aqueous dispersion oxidation.

UNLABELLED: Antioxidant activities of Myrtus communis leaf phenolic compounds (McPCs) were investigated on 2,2'-9-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS(+) •) and oxygen radical absorbance capacity (ORAC) tests or on oxidation of biological models, human low-density lipoprotein (LDL) and phospholipid aqueous dispersion (L-α-phosphatidylcholine stabilized by bile salts). Two extraction techniques, microwave-assisted (MAE) and conventional (CE), were used to isolate McPCs, producing similar results of phenolic compound content. ABTS(+) • assay showed clearly that myrtle extracts exhibited a stronger scavenging effect than butylated hydroxyanisole and α-tocopherol, with a slight advantage for myrtle CE extract. In ORAC assay, the both McPC extracts were similarly less effective than the pure compounds as caffeic acid and myricitrin (myricetin 3-O-rhamnoside) but stronger than butylated hydroxytoluene. Moreover, myrtle CE and MAE extracts, and myricitrin were able to inhibit similarly the production of conjugated dienes and to prolong the lag phase (Tlag) during Cu(2+)-induced LDL oxidation with a dose-response effect. The cryo-electron microscopy observations on studied phospholipid dispersion stabilized by bile salts (BS) revealed the presence of bilayer vesicles and micelles. In 2,2'-azobis (2-amidinopropane) hydrochloride-induced phospholipid/BS oxidation, myrtle CE and MAE extracts gave similar effects to α-tocopherol and caffeic acid but myricitrin showed a higher protective effect than myrtle extracts. We showed also that no synergic or additive effect between α-tocopherol and myrtle extracts or caffeic acid in α-tocopherol-enriched phospholipid/BS dispersion, but myricitrin showed an additive effect and thus promoted the total antioxidant activity. These data showed that myrtle extract could be used as potential natural antioxidants, food stabilizers, or natural health products. PRACTICAL APPLICATION: We show that microwave-assisted extraction could be an alternative method for plant phenolic compound recovery allowing important gain in time extraction.We report inhibition of low-density lipoprotein oxidation in vitro initiated by Cu(2+) ions. We report that myrtle extract may be a source of natural antioxidants to counteract phospholipid peroxidation as well as α-tocopherol.

Antioxidant properties of 3-deoxyanthocyanidins and polyphenolic extracts from Côte d'Ivoire's red and white sorghums assessed by ORAC and in vitro LDL oxidisability tests.

Red sorghum is a source of phenolic compounds (PCs), including 3-deoxyanthocyanidins that may protect against oxidative stress related disease such as atherosclerosis. HPLC was used to characterise and quantify PCs extracted from red or white sorghum whole grain flour. Antioxidant activity was measured by an oxygen radical absorbance capacity assay and against LDL-oxidisability, and further compared to that of synthesised 3-deoxyanthocyanidins (i.e., luteolinidin and apigeninidin). Phenolic content of red and white sorghums was evaluated as 3.90 ± 0.01 and 0.07 ± 0.01 mmol gallic acid equivalents L(-1), respectively. Luteolinidin and apigeninidin were mainly found in red sorghum. Red sorghum had almost 3 and 10 times greater specific antioxidant activity compared to luteolinidin and apigeninidin, respectively. Red sorghum PCs and the two 3-deoxyanthocyanidins were also effective at preventing LDL vitamin E depletion and conjugated diene production. Red sorghum flour exhibits antioxidant capacity suggesting that it may be a valuable health-promoting food.

Dietary fatty acids modulate liver mitochondrial cardiolipin content and its fatty acid composition in rats with non alcoholic fatty liver disease.

No data are reported on changes in mitochondrial membrane phospholipids in non-alcoholic fatty liver disease. We determined the content of mitochondrial membrane phospholipids from rats with non alcoholic liver steatosis, with a particular attention for cardiolipin (CL) content and its fatty acid composition, and their relation with the activity of the mitochondrial respiratory chain complexes. Different dietary fatty acid patterns leading to steatosis were explored. With high-fat diet, moderate macrosteatosis was observed and the liver mitochondrial phospholipid class distribution and CL fatty acids composition were modified. Indeed, both CL content and its C18:2n-6 content were increased with liver steatosis. Moreover, mitochondrial ATP synthase activity was positively correlated to the total CL content in liver phospholipid and to CL C18:2n-6 content while other complexes activity were negatively correlated to total CL content and/or CL C18:2n-6 content of liver mitochondria. The lard-rich diet increased liver CL synthase gene expression while the fish oil-rich diet increased the (n-3) polyunsaturated fatty acids content in CL. Thus, the diet may be a significant determinant of both the phospholipid class content and the fatty acid composition of liver mitochondrial membrane, and the activities of some of the respiratory chain complex enzymes may be influenced by dietary lipid amount in particular via modification of the CL content and fatty acid composition in phospholipid.

Rat liver mitochondrial membrane characteristics and mitochondrial functions are more profoundly altered by dietary lipid quantity than by dietary lipid quality: effect of different nutritional lipid patterns.

Dietary lipids are known to affect the composition of the biological membrane and functions that are involved in cell death and survival. The mitochondrial respiratory chain enzymes are membrane protein complexes whose function depends on the composition and fluidity of the mitochondrial membrane lipid. The present study aimed at investigating the impact of different nutritional patterns of dietary lipids on liver mitochondrial functions. A total of forty-eight Wistar male rats were divided into six groups and fed for 12 weeks with a basal diet, lard diet or fish oil diet, containing either 50 or 300 g lipid/kg. The 30 % lipid intake increased liver NEFA, TAG and cholesterol levels, increased mitochondrial NEFA and TAG, and decreased phospholipid (PL) levels. SFA, PUFA and unsaturation index (UI) increased, whereas MUFA and trans-fatty acids (FA) decreased in the mitochondrial membrane PL in 30 % fat diet-fed rats compared with 5 % lipid diet-fed rats. PL UI increased with fish oil diet v. basal and lard-rich diets, and PL trans-FA increased with lard diet v. basal and fish oil diets. The 30 % lipid diet intake increased mitochondrial membrane potential, membrane fluidity, mitochondrial respiration and complex V activity, and decreased complex III and IV activities. With regard to lipid quality effects, ß-oxidation decreased with the intake of basal or fish oil diets compared with that of the lard diet. The intake of a fish oil diet decreased complex III and IV activities compared with both the basal and lard diets. In conclusion, the characteristics and mitochondrial functions of the rat liver mitochondrial membrane are more profoundly altered by the quantity of dietary lipid than by its quality, which may have profound impacts on the pathogenesis and development of non-alcoholic fatty liver disease.

Potential health implication of in vitro human low-density lipoprotein-vitamin E oxidation modulation by polyphenols derived from Côte d'Ivoire's oil palm species.

Antioxidant activities of polyphenolic compounds extracted (PPEs) from ripe fruits of oil palms are investigated by studying their in vitro effects on human low-density lipoprotein (LDL) oxidation. Four oil palm species ( Elaeis guineensis ) are issued from the National Centre of Agronomic Research of Côte d'Ivoire, of which two are parental varieties (HP1 and HP2), while the other two are crossing varieties (HP3 and HP4). The main identified compounds were rutin (HP3 and HP4) and caffeic and chlorogenic (5-caffeoyl quinic) acids (HP1, HP3, and HP4). The highest total phenolic content was found for HP4, while it was significantly lower for HP2. Antioxidative effects were monitored by Cu(2+)- or 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH)-induced generation of conjugated dienes (lag time and oxidation rate). The highest PPE specific antioxidant activity (SAA) values were obtained with crossing varieties (HP3 and HP4) in the copper-oxidation assay. In the AAPH-oxidation assay, SAA values were comparable for all four varieties. PPEs were effective at preventing LDL-vitamin E depletion in vitro. They could exert direct beneficial antioxidant effects on vitamin E and other antioxidants contained in food and beverages in vivo, within the gastrointestinal (GI) tract. These data could also be of particular importance for a healthier nutrition or the management of chronic diseases by a polyphenol-rich diet.

A grape polyphenol extract modulates muscle membrane fatty acid composition and lipid metabolism in high-fat--high-sucrose diet-fed rats.

Accumulation of muscle TAG content and modification of muscle phospholipid fatty acid pattern may have an impact on lipid metabolism, increasing the risk of developing diabetes. Some polyphenols have been reported to modulate lipid metabolism, in particular those issued from red grapes. The present study was designed to determine whether a grape polyphenol extract (PPE) modulates skeletal muscle TAG content and phospholipid fatty acid composition in high-fat-high-sucrose (HFHS) diet-fed rats. Muscle plasmalemmal and mitochondrial fatty acid transporters, GLUT4 and lipid metabolism pathways were also explored. The PPE decreased muscle TAG content in HFHS/PPE diet-fed rats compared with HFHS diet-fed rats and induced higher proportions of n-3 PUFA in phospholipids. The PPE significantly up-regulated GLUT4 mRNA expression. Gene and protein expression of muscle fatty acid transporter cluster of differentiation 36 (CD36) was increased in HFHS diet-fed rats but returned to control values in HFHS/PPE diet-fed rats. Carnitine palmitoyltransferase 1 protein expression was decreased with the PPE. Mitochondrial ß-hydroxyacyl CoA dehydrogenase was increased in HFHS diet-fed rats and returned to control values with PPE supplementation. Lipogenesis, mitochondrial biogenesis and mitochondrial activity were not affected by the PPE. In conclusion, the PPE modulated membrane phospholipid fatty acid composition and decreased muscle TAG content in HFHS diet-fed rats. The PPE lowered CD36 gene and protein expression, probably decreasing fatty acid transport and lipid accumulation within skeletal muscle, and increased muscle GLUT4 expression. These effects of the PPE are in favour of a better insulin sensibility.

A polyphenol extract modifies quantity but not quality of liver fatty acid content in high-fat-high-sucrose diet-fed rats: possible implication of the sirtuin pathway.

High-fat or high-fat-high-sucrose diets are known to induce non-alcoholic fatty liver disease and this is emerging as one of the most common liver diseases worldwide. Some polyphenols have been reported to decrease rat hepatic lipid accumulation, in particular those extracted from red grapes such as resveratrol. The present study was designed to determine whether a polyphenol extract (PPE), from red grapes, modulates liver fatty acid composition and desaturase activity indexes in rats fed a high-fat-high-sucrose (HFHS) diet, and to explore whether sirtuin-1 deacetylase activation was implicated in the effect of the PPE against liver steatosis. The effect of this PPE on mitochondriogenesis and mitochondrial activity was also explored. The PPE decreased liver TAG content in HFHS+PPE diet-fed rats in comparison with HFHS diet-fed rats. The PPE had no effect on liver fatty acid composition, desaturase activity indexes and stearoyl-CoA desaturase 1 (SCD1) gene expression. Sirtuin-1 deacetylase protein expression was significantly increased with the PPE; AMP kinase protein expression was higher with the PPE in comparison with the HFHS rats, but no modification of phosphorylated AMP kinase was observed. Protein expression of phospho-acetyl-CoA carboxylase was decreased in HFHS rats and returned to basal values with the PPE. Finally, the PPE modulated PPARγ coactivator-1α (PGC-1α) but did not modify mitochondriogenesis and mitochondrial activity. In conclusion, the PPE partially prevented the accumulation of TAG in the liver by regulating acetyl-CoA carboxylase phosphorylation, a key enzyme in lipid metabolism, probably via sirtuin-1 deacetylase activation. However, the PPE had no effect on the qualitative composition of liver fatty acids.

Diagnosis of iron deficiency anemia in children of Northeast Brazil.

OBJECTIVE: To diagnose iron deficiency anemia in children. METHODS: The study was conducted with a sample of 301 children aged six to 30 months attending public daycare centers in the city of Recife, Northeast Brazil, in 2004. The diagnoses of anemia were based on a combination of different hematological and biochemical parameters: hemoglobin, mean corpuscular volume, ferritin, C-reactive protein, transferrin saturation and transferrin receptor. The chi-square test and ANOVA were used in the statistical analysis. RESULTS: Of all children studied, 92.4% had anemia (Hb<110 g/L) and 28.9% had moderate/severe anemia (Hb<90 g/L). Lower levels of hemoglobin were found in children aged 6-17 months. Iron deficiency was found in 51.5% of children using ferritin (<12 microg/L) as parameter. Taking into consideration the combination of hemoglobin level, ferritin and transferrin receptor, 58.1% had anemia with iron deficiency, 34.2% had anemia without iron deficiency and 2.3% had iron deficiency without anemia. Mean ferritin concentration was significantly higher in children with high C-reactive protein when compared with those with normal levels (22.1 vs. 14.8 microg/L). CONCLUSIONS: The use of several biochemical and hematological parameters allowed to diagnosing iron deficiency anemia in two thirds of children, suggesting a need to identify other determinants of anemia without iron deficiency.

Diagnosis of iron deficiency anemia in children of Northeast Brazil / Diagnóstico de anemia por deficiencia de hierro en niños del Noreste de Brasil

OBJETIVO: Diagnosticar anemia por deficiência de ferro em crianças. MÉTODOS: O estudo foi desenvolvido com uma amostra de 301 crianças com idade entre seis e 30 meses, usuárias de creches públicas de Recife, PE, em 2004. Para o diagnóstico da anemia utilizou-se a combinação de diferentes parâmetros hematológicos e bioquímicos: hemoglobina, volume corpuscular médio, ferritina, proteína C-reativa, saturação da transferrina e receptor da transferrina. Para a análise estatística empregou-se o teste do qui-quadrado e ANOVA. RESULTADOS: Do total de crianças, 92,4 por cento tinha anemia (Hb < 110g/L) e 28,9 por cento apresentou anemia moderada/grave (Hb<90g/L). Níveis mais baixos de hemoglobina foram observados em crianças de seis a 17 meses. Encontrou-se deficiência de ferro em 51,5 por cento das crianças, utilizando-se a ferritina (< 12µg/L) como parâmetro. Considerando a combinação da concentração de hemoglobina, ferritina e do receptor de transferrina, 58,1 por cento tinha anemia com deficiência de ferro, 34,2 por cento anemia sem déficit de ferro e 2,3 por cento deficiência de ferro sem anemia. A concentração média de ferritina foi significativamente maior em crianças com proteína C-reativa aumentada quando comparada com aqueles com níveis normais (22,1 versus 14,8 µg/L). CONCLUSÕES: A utilização de diversos parâmetros bioquímicos e hematológicos possibilitou diagnosticar anemia por deficiência de ferro em dois terços das crianças, revelando a necessidade de identificar outros determinantes de anemia sem deficiência de ferro.

OBJETIVO: Diagnosticar anemia por deficiência de ferro em crianças. MÉTODOS: O estudo foi desenvolvido com uma amostra de 301 crianças com idade entre seis e 30 meses, usuárias de creches públicas de Recife, PE, em 2004. Para o diagnóstico da anemia utilizou-se a combinação de diferentes parâmetros hematológicos e bioquímicos: hemoglobina, volume corpuscular médio, ferritina, proteína C-reativa, saturação da transferrina e receptor da transferrina. Para a análise estatística empregou-se o teste do qui-quadrado e ANOVA. RESULTADOS: Do total de crianças, 92,4% tinha anemia (Hb < 110g/L) e 28,9% apresentou anemia moderada/grave (Hb<90g/L). Níveis mais baixos de hemoglobina foram observados em crianças de seis a 17 meses. Encontrou-se deficiência de ferro em 51,5% das crianças, utilizando-se a ferritina (< 12µg/L) como parâmetro. Considerando a combinação da concentração de hemoglobina, ferritina e do receptor de transferrina, 58,1% tinha anemia com deficiência de ferro, 34,2% anemia sem déficit de ferro e 2,3% deficiência de ferro sem anemia. A concentração média de ferritina foi significativamente maior em crianças com proteína C-reativa aumentada quando comparada com aqueles com níveis normais (22,1 versus 14,8 µg/L). CONCLUSÕES: A utilização de diversos parâmetros bioquímicos e hematológicos possibilitou diagnosticar anemia por deficiência de ferro em dois terços das crianças, revelando a necessidade de identificar outros determinantes de anemia sem deficiência de ferro.

Ellagic acid and its methyl-derivatives inhibit a newly found nitratase activity.

We have recently shown that low density lipoprotein (LDL) was able to denitrate albumin-bound 3-NO(2)-Tyr residues and to concomitantly release NO(3)(-) through a Ca(2+)-dependent process that has been ascribed to a specific protein structure. A lipophilic food component (gamma-tocopherol), which is easily loaded into LDL has been found to totally inhibit denitrating activity. We presently found that ellagic acid (EA) and its methylated derivatives, 4,4'O-methyl- and 3,3'O-methyl-ellagic acids (MeEA1 and MeEA2, respectively), amphipathic phenolic components of certain fruits and beverages, were also able to inhibit this activity, with a total inhibition for EA and a 60% inhibition for MeEA1 and MeEA2. EA exhibited the highest affinity for protein plasma, whereas a higher affinity of MeEA1 and MeEA2 (with MeEA1 > MeEA2) than EA was found for lipoprotein fractions, suggesting that the inhibition-driving property is protein affinity. As a result of this nitratase-inhibition property EA and its natural metabolite MeEA2 may have a beneficial role in special physiopathological conditions.

First evidence for an LDL- and HDL-associated nitratase activity that denitrates albumin-bound nitrotyrosine--physiological consequences.

In the systemic circulation, LDL occurs in the form of a weakly nitrated LDL-albumin complex (LAC). The question here is whether LAC (or HDL) is able to denitrate the albumin-bound 3-NO(2)-tyrosine (3NT). Nitrated albumin was incubated in the presence of lipoprotein fraction (LPF) to be tested, with or without Ca(2+). After precipitation and centrifugation, supernatants (SNs) and protein pellets (PP) were collected. HCl proteolysis was carried out with deuterated 3NT as an internal standard, and amino acids were derivatized for GC-MS analysis, whereas SNs were used for NO(2) (-)/NO(3) (-)-fluorimetric assays. A loss of 3NT, higher with albumin-low LDL than with albumin-rich LDL or HDL, was found in PP only in the presence of Ca(2+). gamma-Tocopherol loading of LPF inhibited 3NT loss. 3NT loss was found for the first time to be stoichiometrically equivalent to NO(3) (-), proving that the 3NT loss must be ascribed to a 3NT-denitrating nitratase activity. 3NT loss and NO(3) (-) production that clearly cannot be attributed to PON-1 were impaired by D-penicillamine and phenylacetate, inhibitor, and substrate of PON-1, respectively, leading to speculate on the active site. Finally, nitratase activity and albumin contribute to beneficially convert peroxynitrite (ONOO(-)) into nonbioactive NO(3) (-). But, in inflammatory conditions, xanthine oxidoreductase is expressed leading to detrimentally reduce O(2) and NO(3) (-) into O(2) (*) (-) and NO(*) that may interact, reconstituting the ONOO(-) pool. The real consequence of nitratase activity and the physiological significance of nitration/denitration processes remain to be explored.

Peroxynitrite mild nitration of albumin and LDL-albumin complex naturally present in plasma and tyrosine nitration rate-albumin impairs LDL nitration.

In blood, peroxynitrite (ONOO- ) and CO2 react to form NO2* and CO3* through the short-lived adduct ONOOCO2-, leading to protein-bound tyrosine nitration. ONOO(-) -modified LDL is atherogenic. Oxidatively modified LDL generally appears in the vessel wall surrounded by antioxidants. Human serum albumin (HSA) is one of them, partly associated to LDL as a LDL-albumin complex (LAC). The purpose was to study the effect of a mild nitration on LAC and whether albumin may interfere with LDL nitration. To do so, SIN-1 was used as ONOO- generator in the presence or absence of 25 mM HCO3-. The human serum albumin (HSA)-bound tyrosine nitration rate was found to be 4.4 x 10(-3) mol/mol in the presence of HCO3-. HSA decreased the LAC-tyrosine nitration rate from 2.5 x 10(-3) to 0.6 x 10(-3) mol/mol. It was concluded that HSA impaired the apoB-bound tyrosine nitration. These findings raise the question of the patho-physiological significance of these nitrations and their interactions which may potentially prevent both atheromatous plaque formation and endothelium dysfunction in particular and appear to be beneficial in terms of atherogenic risk.

Potential anti-atherogenic cell action of the naturally occurring 4-O-methyl derivative of gallic acid on Ang II-treated macrophages.

We have recently established that the blood concentrations of gallic acid (GA), a polyphenolic component naturally found in food, and its O-methyl derivatives are very low (practically < or = 1 microM) in physiological (postprandial) condition. Using acellular oxidant systems and macrophage-differentiated promonocytes (MDPs) THP-1, we show here that the direct and indirect (through depressing effect on the superoxide cell production) antioxidant properties of these components were not effective at these concentrations. In contrast, 4-O-methyl GA was the most efficient component to depress AT1R and CD36 mRNA expression in Ang II-treated MDPs, suggesting a strong inhibition of Ang II-triggered pro-atherogenic mechanisms of foam cell formation.

Red-wine beneficial long-term effect on lipids but not on antioxidant characteristics in plasma in a study comparing three types of wine--description of two O-methylated derivatives of gallic acid in humans.

The purpose of this double clinical study was (1) to evaluate the effect of one single intake (300 ml) of red wine (RW) on the plasma antioxidant capacity (pAOC) and plasma phenolics over the 24-h time period following the intake, and (2) to compare the long-term effects of daily intakes (250 ml/d) of RW, white wine (WW) and Champagne (CH) on the plasma and LDL characteristics of healthy subjects. In the first part, blood samples were collected just before and after wine consumption. In the second part, subjects received the 3 types of wine successively, only at the mealtime, over 3-week periods separated by a 3-week wash out. Blood samples were drawn in fasting condition before and after each 3-week wine consumption period. The peak of pAOC was at 3-4 h following the single intake of RW, that of catechin was at 4 h (0.13 micromol/l) and that of gallic acid and caffeic acid was earlier (< or = 1.5 and 0.3 micromol/l, respectively). In plasma, the major form of gallic acid was 4-O-methylated, but a minor form (the 3-O-methyl derivative) appeared. In the long term study, no wine was able to change LDL oxidizability, but some other parameters were modified specifically: RW decreased pAOC (without changing TBARS and uric acid plasma levels), LDL lipids and total cholesterol (TC), and increased plasma apoA1, whereas CH increased plasma vitamin A. The beneficial effect of RW seems to mainly be explained by its action on lipid and lipoprotein constants, and not by its antioxidant one.

Vitamin E supplementation increases LDL resistance to ex vivo oxidation in hemodialysis patients.

BACKGROUND: Oxidative stress and alterations in lipid metabolism observed in hemodialysis patients potentiate the low-density lipoprotein (LDL) oxidability, recognized as a key event during early atherogenesis. OBJECTIVE: To explore the effects of an oral vitamin E supplementation on oxidative stress markers and LDL oxidability in hemodialysis patients. METHODS: Fourteen hemodialysis patients and six healthy volunteers were given oral vitamin E (500 mg/day) for six months. Oxidative stress was assessed using: plasma and lipoprotein vitamin E levels [high-performance liquid chromatography (HPLC) procedure]; thiobarbituric acid reactive substances (TBARS, Yaggi method); and copper-induced LDL oxidation. All parameters were evaluated before initiation of vitamin E supplementation, and at three and six months thereafter. RESULTS: At baseline, a significantly higher TBARS concentration and a higher LDL oxidability were observed in hemodialysis patients when compared to controls. After six months of vitamin E supplementation, TBARS and LDL oxidability were normalized in hemodialysis patients. CONCLUSION: Our data confirm that hemodialysis patients are exposed to oxidative stress and increased susceptibility to ex vivo LDL oxidation. Since oral vitamin E supplementation prevents oxidative stress and significantly increases LDL resistance to ex vivo oxidation, supplementation by natural antioxidants such as vitamin E may be beneficial in hemodialysis patients.

Grape and grape seed extract capacities at protecting LDL against oxidation generated by Cu2+, AAPH or SIN-1 and at decreasing superoxide THP-1 cell production. A comparison to other extracts or compounds.

A large body of evidence supports the key role of oxidized low-density lipoprotein in atherosclerosis. The aim of this study was to compare the capacity of natural polyphenols (PP) from Vitis vinifera and Olea europea at protecting LDL against oxidation brought about by Cu2+, oxygen-centered radical-generating AAPH, or peroxynitrite-generating SIN-1 in vitro systems, or at impairing superoxide production in promonocyte cells (THP-1) conveniently differentiated into adherent macrophages. PP were either from the whole grape (fraction A) containing mainly procyanidins, (epi)-catechin and anthocyanins, or from grape seed extracts (fractions B and C) consisting of tannins and procyanidin oligomers with a higher content in B than in C, or from a grape skin extract (fraction D) consisting mainly of anthocyanins, or from a hydrosoluble olive mill wastewater PP extract (fraction E) containing hydroxytyrosol and oleuropein. Chlorogenic acid (F) and catechin (G) were taken as archetypes of PP preventing oxidation partly as copper scavenger and as radical scavenger only, respectively. All grape fractions were efficient towards Cu2+ system (equally or more efficient than F), whereas they were rather poorly efficient towards AAPH and SIN-1 (less efficient than G but as efficient as F). Among the PP fractions, B was the most effective at protecting LDL in the SIN-1 system and at impairing THP-1 superoxide production. Taken together, these data suggest that the PP fraction from grape seed rich in procyanidins achieves the best compromise between the direct and indirect (i.e. cell-mediated) types of action in protecting LDL against oxidation, strengthening the need for improving the knowledge of its bioavailability in humans.

Synergistic antioxidative properties of phenolics from natural origin toward low-density lipoproteins depend on the oxidation system.

Using an approach in line with that of a previous report, we assessed the antioxidant activity of several natural, polyphenol- or tocotrienol-rich mixtures: extracts from Elaesis Guineensis oil (A) and Vitis vinifera (B), a Coffea robusta powder (C), and extracts from Olea europea mill wastewaters (D), Solanum melongena (E), and Lycopersicon esculentum (F). The copper- and 2-2'-azobis(2-amidinopropane) hydrochloride (AAPH)-oxidation systems were used in the presence of low-density lipoprotein. For comparison, antioxidant activities of chlorogenic acid and catechin, as archetypes of molecules highly efficient with the copper- and the AAPH-oxidation system, respectively, were assessed. The aim was to establish the occurrence of synergistic antioxidant actions among some of these natural mixtures. On a molar basis, the highest specific antioxidant activities (SAA) were found for B, chlorogenic acid, and C in the copper system, and for A, catechin, and B in the AAPH system. On a mass basis, the highest SAA were found, respectively, for chlorogenic acid, B, and catechin, and for catechin, chlorogenic acid, and B. These results show that large discrepancies take place in the evaluations between the two systems. B and C exhibited a synergistic antioxidant efficiency, in the presence or absence of A, but only with the copper system. This was also true for the two types of A+B+C mixture that were tested. It is thought that this association might provide an ideal combination, incorporating both the radical scavenger and the transition-metal ion chelation properties of B and C.

Cord blood essential fatty acid and alpha-tocopherol in full-term newborns in a Northeast Brazil area.

Malnutrition of children during the first two years of life constitutes a public health concern in Brazil, particularly in the Northeast. Most of the nutrition data are concerned with protein-energy malnutrition and hypovitaminosis A. The purpose of this cross-sectional study was to assess the essential fatty acid (EFA) status, which is crucial in physical and mental development, and that of vitamin E which prevents against the oxidative loss of EFA physiological properties, in 81 full-term newborns. Blood samples were obtained from the residual blood of the umbilical cord (UC) at delivery. Fatty acid composition of UC plasma did not show any sign of EFA deficiency. The levels of docosahexanoic (DHA) and arachidonic acid (AA) appeared to be quite similar to those obtained in European populations. UC plasma vitamin E content was 6.31 +/- 1.99 mumol/L whereas the lipid-normalized vitamin E was 2.36 mumol/mmol of lipids. An interesting point was that newborns with vitamin E inferior to the median value (5.80 mumol/L) revealed significantly lower contents of linoleic acid and DHA in UC than newborns superior to the median value. Together with the absolute or normalized plasma level of vitamin E, this supports the observation that one quarter of the community's newborns is deficient in vitamin E.

New insight on the relationship between LDL composition, associated proteins, oxidative resistance and preparation procedure.

Oxidized low density lipoprotein (LDL) plays an important role in atherogenesis. It is generally thought that LDL is mainly oxidized in the intima of vessel walls, surrounded by hydrophilic antioxidants and proteins such as albumin. The aim of this study was to investigate the possible interrelationships between oxidation resistance of LDL and its protein and lipid moieties. Proteins and to a lesser extent lipids, appeared to be the major determinants in the LDL Cu2+-oxidation resistance, which in turn depend on the ultracentrifugation (UC) procedure used. Comparing high speed/short time (HS/ST, 4 h), high speed/long time (HS/LT, 6-16h) and low speed/long time (LS/LT, 24h) conditions of UC, HS with the shortest time (4h) led to prepare LDL (named LDL.HS-4 h) with higher total protein and triglyceride contents, unchanged total cholesterol, phospholipids and Vitamin E, and higher Cu2+-oxidation resistance. Among proteins, only albumin allows to explain changes. PAF acetyl hydrolase appeared to be unaffected, whereas its pro-oxidant role was established and found only in the absence of albumin. In contrast the pro-oxidant role of caeruloplasmin took place regardless of the albumin content of LDL. The antioxidant effect of albumin (the oxidation lag time was doubled for 20mol/mol albumin per LDL) is assumed to be due to its capacity at decreasing LDL affinity for Cu2+. Interestingly, the LDL.HS-4 h albumin content mirrored the intrinsic characteristics of LDL in the plasma and was not affected by added free albumin. Moreover, it has been verified that in 121 healthy subjects albumin was the best resistance predictor of the Cu2+-oxidation of LDL.HS-4 h, with a multiple regression equation: lag time (min) = 62.1 + 0.67(HSA/apoB) + 0.02(TG/apoB)-0.01(TC/apoB); r = 0.54, P < 0.0001. Accounted for by lag time, the oxidation resistance did not correlate with alpha-tocopherol and ubiquinol contents of LDL. The mean albumin content was about 10mol/mol, and highly variable (0-58 mol/mol) with subjects. The LDL.HS-4h may account for the status of LDL in its natural environment more adequately than LDL resulting from other conditions of UC.