Induced Oxidation (induced + oxidation)

Distribution by Scientific Domains


Selected Abstracts


Antioxidant properties of extracts and compounds from Psoralea morisiana

EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 7-8 2005
Antonella Rosa
Abstract The antioxidant activity of various extracts (MeOH, petroleum ether, EtOAc) from the aerial parts of Psoralea morisiana, an endemic Sardinian plant, was evaluated during autoxidation and iron-mediated oxidation of linoleic acid at 37,°C and during cholesterol oxidation at 140,°C, in the absence of solvent. The activity of erybraedin,C, bitucarpin,A and plicatin,B, isolated from the extracts, was investigated under the same experimental conditions and compared to that of BHT and ,-tocopherol. All the extracts, erybraedin,C (major constituent of the extracts) and plicatin,B showed powerful antioxidant properties. None of the extracts and pure compounds showed any prooxidant activity. The cytotoxicity of the extracts, erybraedin,C, and plicatin,B was further evaluated in VERO cells, a line of fibroblasts derived from monkey kidney. Erybraedin,C, at non-cytotoxic concentrations, showed a strong inhibition of FeCl3 -induced oxidation in VERO cells. [source]


Effect of dietary linoleic acid concentration and vitamin E supplementation on cell desquamation and susceptibility to oxidative damage of pig jejunal mucosa

JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1-2 2001
C. J. López Bote
Sixty Large White × Great York pigs weighing approximately 60 kg were individually fed on six experimental diets. The experiment was organized in a 3 × 2 factorial arrangement design with three different fat sources and a basal or supplemented (200 mg/kg diet) level of ,-tocopheryl acetate. All diets contained the same concentration of saturated fatty acids (15 ± 0.2 g/kg dry matter) but differed in the concentration of C18 : 2 (14 ± 0.5, 18 ± 0.4 and 21 ± 0.6 g/kg) and monounsaturated fatty acids (19 ± 0.2, 15 ± 1.2 and 10 ± 1.3 g/kg). No effect of dietary treatment was observed on weight gain and feed consumption. A histological study of the jejunal mucosa showed lower cell desquamation in groups containing a supplemental level of ,-tocopheryl acetate (p=0.080). A higher cell desquamation was found in the groups fed diets containing the higher concentration of C18 : 2 (p=0.087). We also observed an interaction effect (p < 0.001) of dietary fat source and vitamin E supplementation on jejunal cell desquamation in which the effect of dietary vitamin E was lower when diets with a low concentration of C18 : 2 were administered. In vitro- induced oxidation of jejunal mucosa homogenates was lower in pigs fed diets supplemented with ,-tocopheryl acetate (p < 0.002). The dietary concentration of C18 : 2 significantly affected oxidation of pig jejunal mucosa (p < 0.002). [source]


Cranberry proanthocyanidins associate with low-density lipoprotein and inhibit in vitro Cu2+ -induced oxidation,

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2001
Mandy L Porter
Abstract Antioxidant activity of six fractions of cranberry phenolic compounds was determined by inhibition of Cu2+ -induced low-density lipoprotein (LDL) oxidation. The phenolic composition of each fraction was determined by high-performance liquid chromatography. The phenolic fractions were mixed with aliquots of modified human serum prior to LDL isolation. The serum was modified to remove very-low-density lipoprotein and chylomicrons that may bind phenolic compounds. Only fractions 5 and 6 that contained proanthocyanidins (PAs) significantly increased the lag time of LDL oxidation, and the lag time for fraction 6 was significantly higher than for fraction 5. The mass distribution of PAs in these fractions was obtained by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry, a technique that allows rapid characterisation of the molecular weight distribution in mixtures of oligomeric compounds. Fraction 5 contained trimers through heptamers, whereas fraction 6 contained pentamers through nonamers. In addition, fraction 6 contained PA oligomers with more doubly linked, A-type interflavan bonds. Results indicate that PAs specifically associate with LDL in modified serum and increase the lag time of Cu2+ -induced oxidation. Differences between fractions 5 and 6 in PA structure and effects on LDL oxidation suggest that the degree of polymerisation and the nature of the interflavan bond influence antioxidant properties. © 2001 Society of Chemical Industry [source]


Nanodisks protect amphotericin B from ultraviolet light and oxidation-induced damage

PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 6 2009
Megan L Tufteland
Abstract BACKGROUND: Macrolide polyene antibiotics possess potent broad-spectrum antifungal properties. Use of these agents in the field or in controlled environments is impeded by their poor water solubility and susceptibility to oxidation- and/or light-induced degradation. While typically used for human disease therapy, there is potential to expand the utility of polyene macrolide antibiotics, such as amphotericin B, for control of fungal disease infestation in agricultural settings. Thus, the susceptibility of this antibiotic to exposure-induced activity loss was evaluated. RESULTS: Incubation of the prototype polyene amphotericin B (AMB) with phospholipid vesicles and apolipoprotein A-I results in the formation of nanoscale complexes, termed nanodisks (NDs), capable of solubilizing significant quantities of AMB. To evaluate whether AMB incorporation into NDs conferred protection against light- or oxidation-induced damage, yeast growth inhibition assays were conducted. Compared with AMB solubilized in detergent micelles, AMB incorporated into NDs was protected from damage caused by exposure to UV light as well as by KMnO4 -induced oxidation. Furthermore, AMB-NDs inhibited growth of the turfgrass fungus Marasmius oreades Fr. CONCLUSION: Results suggest that this water-soluble formulation of a natural, biodegradable, antifungal agent represents a potential cost-effective, non-toxic and environmentally friendly substitute for chemical agents currently employed to control a range of fungal infestations. Copyright © 2009 Society of Chemical Industry [source]


Influence of NO2 molecule adsorption on free charge carriers and spin centers in porous silicon

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2005
E. A. Konstantinova
Abstract The effect of nitrogen dioxide (NO2) adsorption on free charge carriers and spin centers in porous silicon has been studied by FTIR and ESR spectroscopy. The silicon dangling bond (Pb1 -center) density rises with increasing NO2 pressure (P) while free charge carrier concentration depends on P nonmonotonically. The experimental results are explained by a microscopic model taking into account both the formation of P,(NO2), donor,acceptor pairs and NO2 -induced oxidation of Si nanocrystal surfaces. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


ANTI-OXIDANT MECHANISMS OF KOLAVIRON: STUDIES ON SERUM LIPOPROTEIN OXIDATION, METAL CHELATION AND OXIDATIVE MEMBRANE DAMAGE IN RATS

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 8 2005
EO Farombi
SUMMARY 1.,In the present study, we have examined the ability of kolaviron, a natural biflavonoid from Garcinia kola seeds, to prevent the susceptibility of rat serum lipoprotein to undergo oxidative modification in vitro and ex vivo. In addition, its ability to chelate metal ions and mitigate iron/ascorbate-induced damage to microsomal lipids was investigated. 2.,Lipoprotein resistance to copper-induced oxidation was highly improved in rats treated with kolaviron (100 mg/kg) for 7 days, as demonstrated by a significant increase in lag time compared with control. A significant (P < 0.05) decrease in area under the curve (AUC) and slope of propagation was observed in kolaviron-treated rats compared with control. Conjugated dienes formed after 240 min of lipoprotein oxidation were markedly decreased in kolaviron-treated rats compared with controls. Malondialdehyde concentrations were significantly reduced in the serum lipoproteins of kolaviron-treated rats with an attendant significant increase in the total anti-oxidant activity compared with control. 3.,In vitro, kolaviron (10,60 µmol/L) inhibited the Cu2+ -induced oxidation of rat serum lipoprotein in a concentration-dependent manner. Kolaviron, at 20 and 60 µmol/L, produced 48 and 87% inhibition of oxidation of lipoprotein, respectively. Compared with control, kolaviron, at 10 and 20 µmol/L, resulted in 29 and 47% decreases in AUC, respectively. In addition, kolaviron (10 µmol/L) elicited a 53% increase in lag time, whereas 40 and 60 µmol/L kolaviron produced 38 and 88% decreases in slope, respectively. 4.,Kolaviron effectively prevented microsomal lipid peroxidation induced by iron/ascorbate in a concentration-dependent manner. Kolaviron at the highest dose tested (90 µmol/L) had a significant chelating effect on Fe2+ (78%). 5.,In conclusion, our data demonstrate that kolaviron protects against the oxidation of lipoprotein, presumably by mechanisms involving metal chelation and anti-oxidant activity, and, as such, may be of importance in relation to the development of atherosclerosis. [source]