Human Low-density Lipoprotein Oxidation Research Articles

Synthesis and pharmacological evaluation of antioxidant chalcone derivatives of 2(3H)-benzoxazolones

Chalcones featuring an analgesic/anti-inflammatory pharmacophore, i.e., the 2(3H)-benzoxazolone heterocycle, on the one hand, and a radical scavenger moiety, i.e., 2,6-di-t-butylphenol, on the other hand were synthesized by condensation of a ketone 2(3H)-benzoxazolone precursor with 3,5-di-t-butyl-4-hydroxybenzaldehyde. Among the various methods explored (acid homogenous or heterogenous catalysis, base catalysis), heterogenous catalysis conditions using KSF Montmorillonite were found to be the most convenient. The E-geometry of the so-obtained chalcones was ascertained both by 1H and 13C-nuclear magnetic resonance (NMR) spectroscopy as well as B3LYP/6-31G** quantum mechanics calculations. Chalcones 1–8 were pharmacologically evaluated in vitro for their ability to prevent human low-density lipoprotein (LDL) copper-induced oxidation using Cu2+ as oxidizing agent. Compound 4 emerged as the most promising agent as it was able to inhibit copper-mediated human LDL oxidation with an activity ten times greater than that of Probucol, a reference antioxidant drug.

Antioxidant activity versus cytotoxic and nuclear factor kappa B regulatory activities on HT-29 cells by natural fruit juices

The antioxidant activity (free radical scavenging ability and lipid oxidation inhibitory activity) and the activity in cell culture [influence on HT-29 human colon cancer cell viability and nuclear factor kappa B (NF-κB) activation] of natural fruit juices from red grape, strawberry, cherry and sour cherry were investigated in vitro. Analysis of polyphenolic composition of fruit juices showed the dominant presence of anthocyanins (cyanidin-3-glucoside, cyanidin-3-rutinoside, peonidin-3-rutinoside, pelargonidin-3-glucoside), anthocyanidins (procyanidins B1, B2 and B3), flavonoids (glucosides of myricetin, quercetin and kaempferol), and phenolic acids (neochlorogenic acid, chlorogenic acid, ellagic acid, p-coumaroylquinic acid) in juices. DPPH test and β-carotene bleaching method indicated that grape, strawberry, cherry and sour cherry natural juices (at the concentration of 2.5%) showed very strong free radical scavenging (75–92%) and antioxidant activity (71–94%). In addition, at the concentration of 0.01% they showed complete inhibition of copper-induced oxidation of human LDL (low density lipoprotein). In contrast, selected fruit juices did not show cytotoxic effects on HT-29 cells and NF-κB inhibitory activity (at the concentrations of 0.5 and 2%). Results of this study showed no correlation between the antioxidant activity of natural fruit juices from red grape, strawberry, cherry and sour cherry and their effect on HT-29 cell viability and NF-κB inhibitory activity.

Modification with homocysteine does not increase susceptibility of human low-density lipoprotein to iron-mediated oxidation

Oxidation of human low-density lipoprotein (LDL) is centrally involved in the development of cardiovascular diseases. This study investigated whether homocysteine-mediated thiolation of LDL rendered it more susceptible to oxidation by iron. After in vitro exposure to homocysteine thiolactone for 60 minutes, LDL's thiol content increased from 26 +/- 5 (control) to 224 +/- 20 nmol/mg of protein (thiolated; P < .0001). Control and thiolated LDL (0.2 mg of protein per milliliter) were incubated with either redox active iron (Fe(3+); 10 micromol/L) or, as a positive control, copper (Cu(2+); 10 micromol/L). Consistent with the observation of others, thiolation decreased Cu(2+)-dependent formation of lipid oxidation products in LDL (17 +/- 16 nmol/mg of protein formed in thiolated LDL, compared with 81 +/- 21 nmol/mg of protein in control, during 6 hours of incubation; P < .01). Thiolation had no effect, however, on Fe(3+)-mediated oxidation of LDL with lipid oxidation products remaining essentially nondetectable during prolonged incubation (up to 48 hours). Thiolation similarly had no effect on oxidation of LDL (0.2 mg of protein per milliliter) by heme-complexed iron (hemin; 10 micromol/L), with lipid oxidation products increasing to 24 +/- 1 and 27 +/- 4 nmol/mg of protein for control and thiolated LDL, respectively, during 6 hours of incubation (P > .05). Similar results were observed using LDL with varying degrees of thiolation (29 +/- 5, 85 +/- 14, 130 +/- 15, and 213 +/- 19 nmol of thiol per milligram of protein). In conclusion, these results demonstrate that thiolation has no effect on LDL's susceptibility to iron-mediated oxidation.

Antioxidative Activity and Active Components of Longan (Dimocarpus longan Lour.) Flower Extracts

Three different solvent extracts (methanol, ethyl acetate, and n-hexane) of longan ( Dimocarpus longan Lour.) flowers were assayed with three different antioxidant capacity methods, namely, the DPPH free radical scavenging effect, the oxygen radical absorbance capacity (ORAC) assay, and the inhibition of Cu(2+)-induced oxidation of human low-density lipoprotein (LDL). It was revealed that the methanol extract has the best antioxidative activity, followed by ethyl acetate and n-hexane extracts. The methanol extract was separated by liquid-liquid partition into n-hexane, ethyl acetate, n-butanol, and water fractions. The ethyl acetate fraction was found to have the highest activity of delaying LDL oxidation. After silica gel column chromatography, the fraction having a superior activity was identified as containing two major compounds, (-)-epicatechin and proanthocyanidin A2.

Protective effect of the oligomeric acylphloroglucinols from Myrtus communis on cholesterol and human low density lipoprotein oxidation

Myrtle ( Myrtus communis L.), a culinary spice and flavouring agent for alcoholic beverages widespread in the Mediterranean area and especially in Sardinia, contains the structurally unique oligomeric non-prenylated acylphloroglucinols, semimyrtucommulone and myrtucommulone A, whose antioxidant activity was investigated during the oxidative modification of lipid molecules implicated in the onset of cardiovascular diseases. Both acylphloroglucinols showed powerful antioxidant properties during the thermal (140 °C), solvent-free degradation of cholesterol. Moreover, the pre-treatment with semimyrtucommulone and myrtucommulone A significantly preserved LDL from oxidative damage induced by Cu 2+ ions at 2 h of oxidation, and showed remarkable protective effect on the reduction of polyunsaturated fatty acids and cholesterol, inhibiting the increase of their oxidative products (conjugated dienes fatty acids hydroperoxides, 7β-hydroxycholesterol, and 7-ketocholesterol). Taking into account the widespread culinary use of myrtle leaves, the results of the present work qualify the natural compounds semimyrtucommulone and myrtucommulone A as interesting dietary antioxidants with potential antiatherogenicity.

Diphenyl diselenide, a simple glutathione peroxidase mimetic, inhibits human LDL oxidation in vitro

Oxidative modification of low-density lipoprotein (LDL) represents an important factor in atherogenesis. In the present study, we have investigated the antioxidant capability of diphenyl diselenide (PhSe) 2, a simple organoseleno compound, against copper (Cu 2+) and peroxyl radical-induced human LDL oxidation in vitro. In initial studies using human serum, (PhSe) 2 caused a dose-dependent inhibition of Cu 2+-induced lipid peroxidation, which was correlated to thiol consumption. (PhSe) 2 increased lipid peroxidation lag phase and decreased lipid peroxidation rate in isolated human LDL, evaluated by measuring both conjugated diene (CD) and thiobarbituric acid reactive substances (TBARS) levels. Consistent with these observations, (PhSe) 2 showed a marked inhibitory effect on 2,2-azobis(2-amidinopropane dihydrochloride) (AAPH)-induced oxidation of LDL or parinaric acid (PnA) incorporated into LDL. (PhSe) 2 also displayed a dose-dependent protective effect against Cu 2+-induced lipid peroxidation in rat aortic slices. Interestingly, besides the antioxidant effects of (PhSe) 2 toward the lipid moieties of LDL, which was related to its thiol-peroxidase activity, protein moieties from human isolated LDL were also protected against Cu 2+-induced oxidation. The results presented herein are the first to show that (i) (PhSe) 2 inhibits lipid peroxidation in human isolated LDL in vitro, (ii) this phenomenon is related to its thiol-peroxidase activity, and (iii) this chalcogen also prevents the oxidation of protein moieties of human LDL. Taken together, such data render (PhSe) 2 a promising molecule for pharmacological studies with respect to the atherogenic process.

Protective effect against oxidation of human low-density lipoprotein and plasmid DNA strand scission of Tamarind seed coat extract in vitro

Methanolic extract from seed coat of Thai Tamarindus indica L. containing polyphenol; procyanidins, (−)-epicatechin was studied in vitro for protective effect against Cu 2+-induced human low-density lipoprotein (hLDL) oxidation and oxidative damage of plasmid DNA induced by Fenton reactant. LDL oxidation was monitored by formation of conjugated dienes, fluorescent products, protein carbonylation and thiobarbituric acid reactive substances (TBARS). Supercoiled DNA strand scission was evaluated by gel electrophoresis. The extract inhibited formation of all four products of oxidized LDL in a dose-dependent manner over 25–1000 ng/ml extracts. Furthermore, 1 mg/ml extract also protected supercoiled DNA strand in plasmid pBR322 against scission induced by Fenton-mediated hydroxyl radical similar to that found with reference antioxidant, 0.5 μg/ml Trolox. Thus, seed coat extract from Thai Tamarind shows antioxidant effects against in vitro Cu 2+-mediated LDL oxidation and hydroxyl radical–induced supercoiled DNA damage. These results suggest that seed coat extract from Thai Tamarind may be useful for preventing LDL oxidation and DNA damage.

Antioxidant activity and protective effects of green and dark coffee components against human low density lipoprotein oxidation

The in vitro antioxidant activity and the protective effect against human low density lipoprotein oxidation of coffees prepared using different degrees of roasting was evaluated. Coffees with the highest amount of brown pigments (dark coffee) showed the highest peroxyl radical scavenging activity. These coffees also protected human low-density lipoprotein (LDL) against oxidation, although green coffee extracts showed more protection. In a different experiment, coffee extracts were incubated with human plasma prior to isolation of LDL particles. This showed, for the first time, that incubation of plasma with dark, but not green coffee extracts protected the LDL against oxidation by copper or by the thermolabile azo compound AAPH. Antioxidants in the dark coffee extracts must therefore have become associated with the LDL particles. Brown compounds, especially those derived from the Maillard reaction, are the compounds most likely to be responsible for this activity.

Free Radicals and Antioxidants in Cardiovascular Health and Disease

Current hypotheses favour the concept that lowering oxidative stress can have a health benefit. Free radicals can be overproduced or the natural antioxidant system defenses weakened, first resulting in oxidative stress, and then leading to oxidative injury and disease. Cardiovascular disease is one example of this process. This disorder continues to be the major cause of premature death worldwide. Oxidation of human low-density lipoproteins is considered an early step in the progression and eventual development of atherosclerosis, one of the leading causes to cardiovascular dysfunction. Compelling support for the involvement of free radicals in disease development originates from epidemiological studies showing that an enhanced antioxidant status is associated with reduced risk of several diseases. Dietary nutraceuticals such as vitamins C, E and polyphenolics and reduction of cardiovascular disease incidence are a notable example. This paper reviews the biology of ROS/RNS, their pathways through which they relate to the pathology of cardiovascular disease and discusses the putative roles that antioxidants, including phenolics, may play in controlling oxidative stress and reduce the incidence of cardiovascular disease. Keywords: Oxidative stress, cardiovascular disease, atherosclerosis, inflammation, cell signaling and transduction mechanisms, antioxidants, dietary phenolics. Internet Journal of Medical Update Vol. 1 (2) 2006: pp. 24-40

숙성 흑마늘 추출물의 Low Density Lipoprotein (LDL)의 항산화 효과

마늘을 발효시켜 만든 흑마늘의 지질 산화 억제 및 사람 Low Density Lipoprotein (LDL)에 대하여 항산화 활성을 실험하였다. 표준품으로서 마늘의 주성분인 alliin과 흑마늘의 에탄올과 물 추출물의 전자공여능을 각각 비교하여 측정한 결과 흑마늘 에탄을 추출물이 효능이 가장 높았다. 사람 LDL을 <TEX>$Cu^{2+}$</TEX>유도 LDL로 산화시킬 때 그 항산화능은 각 시료를 <TEX>$10\;{\mu}g/ml$</TEX> 및 <TEX>$20\;{\mu}g/ml$</TEX> 씩 첨가하며 TSARS를 측정한 결과 에탄을 추출물이 항산화 활성이 가장 높았으며 용량 의존형으로 나타났다. 흑마늘의 에탄올과 물추출물을 <TEX>$10\;{\mu}g/ml$</TEX> 및 <TEX>$20\;{\mu}g/ml$</TEX> 첨가한 후 J774 유도 산화에 대한 항산화 효과를 측정한 결과 각 추출물은 항산화 효과가 있었고 용량 의존형의 항산화 활성을 나타내었다. 흑마늘의 각 추출물을 이용한 실험에서 전기영동 이동상은 대조구에 비하여 <TEX>$10\;{\mu}g/ml$</TEX> 및 <TEX>$20\;{\mu}g/ml$</TEX>에서 산화를 억제하였고 공액 2중 결합에 의한 실험에서도 항산화 효과가 있었으며 <TEX>$20\;{\mu}g/ml$</TEX>의 농도에서 거의 억제되었다. This study was developed to assess the antioxidative activity of aged black garlic extract on lipid peroxidation and low density lipoprotein (LDL). Antioxidative activity of aged black garlic extract on human low density lipoprotein (LDL) was investigated by monitoring a barbituric acid reactive substance (TBARS). Electron donating ability (EDA) of aged black garlic, ethanol extract was higher than that alliin and water extract. Aged black garlic water and ethanol extracts inhibited the <TEX>$Cu^{2+}$</TEX> mediated oxidation of human LDL in a dose dependent manner at concentration of 10 and <TEX>$20\;{\mu}g/ml$</TEX>. Ethanol extract and water extract of aged black garlic almost completely inhibited J774 mediated LDL oxidation in electrophoretic mobility and conjugated diene. These results indicate that aged black garlic might play a protective antioxidant effects on LDL, probably affecting the structural properties for the LDL oxidation.

Targeted Natural Product Isolation Guided by HPLC–SPE–NMR: Constituents ofHubertiaSpecies

The hyphenated technique, high-performance liquid chromatography-solid-phase extraction-nuclear magnetic resonance spectroscopy (HPLC-SPE-NMR), has been applied for rapid identification of novel natural products in crude extracts of Hubertia ambavilla and Hubertia tomentosa. The technique allowed full or partial identification of all major extract constituents and demonstrated the presence of unusual quinic acid derivatives containing the (1-hydroxy-4-oxocyclohexa-2,5-dienyl)acetyl residue that exhibit strongly coupled ABXY patterns, the parameters of which were obtained by spin simulations. Using homo- and heteronuclear 2D NMR data acquired in the HPLC-SPE-NMR mode, complete structure determination of three new natural products, i.e., 3,5-di-O-caffeoyl-4-O-[(1-hydroxy-4-oxocyclohexa-2,5-dienyl)acetyl]quinic acid (1), its 2-hydroxy derivative (2), and 3,5-di-O-caffeoyl-4-O-[(4-hydroxyphenyl)acetyl]quinic acid (3), was performed. Finally, targeted isolation of 1 was achieved by SPE fractionation and preparative HPLC, followed by evaluation of its antioxidant and antimicrobial activity. In contrast to chlorogenic acid and 3,5-di-O-caffeoylquinic acid, which act as antioxidants, compound 1 proved at the same conditions to possess prooxidant activity in an assay evaluating the oxidation of human low-density lipoprotein induced by Cu(2+).

Pressurized water versus ethanol as a Silybum marianum extraction solvent for inhibition of low-density lipoprotein oxidation mediated by copper and J774 macrophage cellsThis article is one of a selection of papers published in this special issue (part 1 of 2) on the Safety and Efficacy of Natural Health Products.

Silybum marianum contains flavonolignans, termed silymarin (SM), that are therapeutic agents for many inflammation-based diseases including atherosclerosis. Oxidation of human low-density lipoprotein was induced by CuSO4 or J774 macrophage cells and measured by the formation of thiobarbituric acid reactive substances (TBARS). SM was extracted by pressurized hot water (PHWE) or ethanol, and the effects of these extracts on TBARS formation were evaluated in comparison with those of SM preparations made from blending masses of individual flavonolignan standards in ratios identical to those of the water and ethanol extracts. Ethanol-extracted SM and its blended counterpart inhibited the generation of TBARS by 82% and 43%, respectively, at 150 mumol/L doses. TBARS levels in the presence of 150 micromol/L of the PHWE and its blended SM counterpart were reduced by 84% and 38%, respectively. Extracts from milk thistle fruit displayed higher protective effects than blended SM solutions of the same concentration with an identical compositional makeup. The appearance of degradation peaks in the water extract did not create any cytotoxic effects. Results of this study confirm that PHWE can be used to extract flavonolignans from milk thistle and that these extracts may possess therapeutic potential different from or beyond that of traditional organic solvent preparations.

In Vitro Antioxidant Activity of Coffee Compounds and Their Metabolites

In this paper we report the antioxidant activity of different compounds which are present in coffee or are produced as a result of the metabolism of this beverage. In vitro methods such as the ABTS*+ [ABTS = 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] decolorization assay and the oxygen radical absorbance capacity assay (ORAC) were used to assess the capacity of coffee compounds to scavenge free radicals. The importance of caffeine metabolites and colonic metabolites in the overall antioxidant activity associated with coffee consumption is shown. Colonic metabolites such as m-coumaric acid and dihydroferulic acid showed high antioxidant activity. The ability of these compounds to protect human low-density lipoprotein (LDL) oxidation by copper and 2,2'-azobis(2-amidinopropane) dihydrochloride was also explored. 1-Methyluric acid was particularly effective at inhibiting LDL oxidative modification. Different experiments showed that this caffeine metabolite is not incorporated into LDL particles. However, at physiologically relevant concentrations, it was able to delay for more than 13 h LDL oxidation by copper.

Effect of almond skin polyphenolics and quercetin on human LDL and apolipoprotein B-100 oxidation and conformation

Almond skin polyphenolics (ASP) and vitamin C (VC) or E (VE) inhibit the Cu 2+-induced generation of conjugated dienes in human low-density lipoprotein (LDL) in a synergistic manner. However, the mechanism(s) by which this synergy occurs is unknown. As modification of apolipoprotein (apo) B-100 is an early, critical step in LDL oxidation, we examined the effects of combining ASP or quercetin and antioxidant vitamins on the oxidation of this moiety as well as on the alteration of LDL conformation and electronegativity (LDL−). In a dose-dependent manner, ASP (0.12–2.0 μmol/L gallic acid equivalents) decreased tryptophan (Trp) oxidation by 6.7–75.7%, increased the generalized polarity (Gp) of LDL by 21.0–81.5% at 90 min and reduced the ratio of LDL− to total LDL (tLDL) by 38.2–83.8% at 5 h. The actions of ASP on these parameters were generally additive to those of VC and VE. However, a 10–25% synergy of ASP plus VC in protecting apo B-100 Trp against oxidation may result from their synergistic interaction in prolonging the lag time to oxidation. ASP and VE acted in synergy to reduce LDL−/tLDL by 24–43%. Quercetin's actions were similar to ASP, though more effective at inhibiting Trp oxidation. Thus, ASP and quercetin reduce the oxidative modification of apo B-100 and stabilize LDL conformation in a dose-dependent manner, acting in an additive or synergistic fashion with VC and VE.

Physicochemical study of floranol, its copper(II) and iron(III) complexes, and their inhibitory effect on LDL oxidation

The antioxidant activity of floranol (3,5,7,2′-tetrahydroxy-6-methoxy-8-prenylflavanone), a new flavonoid isolated from the roots of Dioclea grandiflora, was evaluated by the inhibition of human low-density lipoprotein (LDL) oxidation. Floranol increased its oxidation lag-phase significantly in a dose-dependent manner. As the antioxidant mechanism may involve metal coordination, we have undertaken a detailed study of floranol interactions with Cu(II) and Fe(III) by combination of UV–visible (UV–Vis) and mass spectrometries and cyclic voltammetry. The acidity constants of the ligand as well as the stability constants of the metal complexes were calculated. The pKa values of 6.58, 11.97 and 13.87 were determined and the following acidity order is proposed 7-OH > 5-OH > 2′-OH. The best fit between experimental and calculated spectra was obtained assuming the formation of two Cu(II) complexes: [CuL] log β = 19.34 ± 0.05 and [CuL 2] 2− log β = 26.4 ± 0.10 and three Fe(III) complexes: [FeL 3] 3− log β = 44.72 ± 0.09, [FeL 2] − log β = 35.32 ± 0.08 and [FeL] + log β = 19.51 ± 0.04. In addition, copper and iron reduction is less favorable in the presence of floranol. These results indicate that floranol can efficiently bind Cu(II) and Fe(III) ions thus preventing their effect on LDL oxidation.

The effect of essential oils of dietary wormwood ( Artemisia princeps), with and without added vitamin E, on oxidative stress and some genes involved in cholesterol metabolism

Wormwood ( Artemisia princeps) due to the abundance of antioxidant in its essential oils (EO), has been used as a traditional drug and health food in Korea. Oxidative stress plays an important role in the etiology of atherosclerosis thus antioxidative chemicals improves hepatic lipid metabolism partly by reducing oxysterol formation. The antioxidant activity was assessed using two methods, human low-density lipoprotein (LDL) oxidation and the anti-DPPH free radical assays. It was found that the antioxidant activity of EO with vitamin E higher than EO alone. To study mechanisms accounting for the antiatherosclerotic properties of this wormwood EO, we examined the expression of key genes in cholesterol metabolism such as the LDL receptor, the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and sterol regulatory element binding proteins. The induction was increased up to twofold at 0.05 mg/mL of EO treatment in HepG2 cells for 24 h. When EO (0.2 mg/mL) was co-incubated with vitamin E, interestingly, the LDL receptor was dramatically induced by 5–6-folds. HMG-CoA reductase did not change. However, treatment with the higher concentration resulted in cytotoxicity. Our data suggest that wormwood EO with vitamin E may be anti-atherogenic due to their inhibition of LDL oxidation and upregulation of the LDL receptor.

Antioxidant Phytochemicals in Hazelnut Kernel (Corylus avellanaL.) and Hazelnut Byproducts

Antioxidant efficacies of ethanol extracts of defatted raw hazelnut kernel and hazelnut byproducts (skin, hard shell, green leafy cover, and tree leaf) were evaluated by monitoring total antioxidant activity (TAA) and free-radical scavenging activity tests [hydrogen peroxide, superoxide radical, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical], together with antioxidant activity in a beta-carotene-linoleate model system, inhibition of oxidation of human low-density lipoprotein (LDL) cholesterol, and inhibition of strand breaking of supercoiled deoxyribonucleic acid (DNA). In addition, yield, content of phenolics, and phenolic acid profiles (free and esterified fractions) were also examined. Generally, extracts of hazelnut byproducts (skin, hard shell, green leafy cover, and tree leaf) exhibited stronger activities than hazelnut kernel at all concentrations tested. Hazelnut extracts examined showed different antioxidative efficacies, expected to be related to the presence of phenolic compounds. Among samples, extracts of hazelnut skin, in general, showed superior antioxidative efficacy and higher phenolic content as compared to other extracts. Five phenolic acids (gallic acid, caffeic acid, p-coumaric acid, ferulic acid, and sinapic acid) were tentatively identified and quantified (both free and esterified forms). Extracts contained different levels of phenolic acids. These results suggest that hazelnut byproducts could potentially be considered as an excellent and readily available source of natural antioxidants.

PHYSICAL CHARACTERISTICS AND ANTIOXIDANT ACTIVITIES OF ORGANIC GRAPES

Studies on antioxidative activities of fruits have focused mainly on grapes, which have been reported to inhibit oxidation of human low-density lipoprotein (LDL) at a level comparable to wine. With regard to consumer attitude on the health benefits of the product, organic grapes were selected for study. Organic grapes of Vitis vinifera origin var. Semillon, Columbard, Cabernet sauvignon, Merlot, Grenache and Carignan produced under the control of International Nutrition and Agriculture Certification Company in Kemalpasa/Ulucak were studied. The order of grape varieties concerning grape cluster, stem and number (100) values from the highest to the lowest was determined as: Semillon > Merlot > Cabernet sauvignon > Carignan > Columbard > Grenache. Positive correlation was determined between antioxidant activities (AOA) and total phenols (r = 0.845; P = 0.034). The highest AOA were determined in Merlot (86.55%) and Cabernet sauvignon (83.60%) varieties. Considering LDL, low-density lipoprotein-diene values for Cabernet sauvignon and Merlot varieties were 82.73 and 65.48%, respectively. The values of low-density lipoprotein-malondialdehyde were different, with the highest percentage found for Semillon (80%). The highest value of total phenols was found in Merlot (4,200 mg/L gallic acid equivalents) variety. Evaluating all analyzed parameters, principal component analysis results demonstrated the similarities between Carignan and Grenache, between Merlot and Cabernet sauvignon and between Columbard and Semillon grape varieties.

Antioxidant Activity of Sicilian Pistachio (Pistacia veraL. Var. Bronte) Nut Extract and Its Bioactive Components

Pistacia vera L. is the only species of Pistacia genus producing edible nuts. This paper investigates the antioxidant potential of a Sicilian variety of pistachio nut by chemical as well as biological assays and measured antioxidant vitamins and a number of antioxidant polyphenols in either the hydrophilic and/or the lipophilic nut extract. In accordance with the majority of foods, the total antioxidant activity, measured as a TAA test, was much higher (50-fold) in the hydrophilic than in the lipophilic extract. Substantial amounts of total phenols were measured. The hydrophilic extract inhibited dose-dependently both the metal-dependent and -independent lipid oxidation of bovine liver microsomes, and the Cu+2-induced oxidation of human low-density lipoprotein (LDL). Peroxyl radical-scavenging as well as chelating activity of nut components may be suggested to explain the observed inhibition patterns. Among tocopherols, gamma-tocopherol was the only vitamin E isomer found in the lipophilic extract that did not contain any carotenoid. Vitamin C was found only in a modest amount. The hydrophilic extract was a source of polyphenol compounds among which trans-resveratrol, proanthocyanidins, and a remarkable amount of the isoflavones daidzein and genistein, 3.68 and 3.40 mg per 100 g of edible nut, respectively, were evaluated. With the exception of isoflavones that appeared unmodified, the amounts of other bioactive molecules were remarkably reduced in the pistachio nut after roasting, and the total antioxidant activity decreased by about 60%. Collectively, our findings provide evidence that the Sicilian pistachio nut may be considered for its bioactive components and can effectively contribute to a healthy status.

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.