Radiation chemistry of fatty and amino acids

Jovanović, Slobodan V.; Josimović, Lj.

doi:10.1002/9780470772508.ch21

Cited by 4 publications

(7 citation statements)

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“…However, this is enough for very efficient in vivo scavenging of the superoxide radical. Given that the reactivities of the superoxide with the biological molecules are of the order of ~1 s −1 or less, 26 even at ~10 −6 M concentrations 31 flavonoids would favorably compete for the superoxide (k = 10 −6 M×10 7 M −1 s −1 = 10 s −1 ).…”

Section: Inactivation Of Superoxide Radical and Singlet Oxygenmentioning

confidence: 99%

Antioxidants in Nutrition

Jovanović

Simic²

2000

Annals of the New York Academy of Sciences

132

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A BSTRACT : The harmful effects of oxidative processes in living organisms, in addition to chemical and biochemical media, can be reduced by antioxidants. The efficacy of an antioxidant depends on its reduction potential and kinetics of elimination of diverse free radicals. Redox potentials and reaction rate constants of selected gallocatechins and flavonoids were measured by pulse radiolysis and laser photolysis. The reduction potentials of the flavonoids studied were in the range of 0.33 V (quercetin) and 0.75 V (kaempferol). The rate constants of the superoxide radical with 15 flavonoids ranged from 10 5 -10 7 M -1 s -1 . Singlet oxygen quenching by flavonoids was also very rapid (from 10 5 to 10 8 M -1 s -1 ). These studies may be crucial in optimizing health and increasing longevity by reducing oxidative stress and biological damage.

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Section: Inactivation Of Superoxide Radical and Singlet Oxygenmentioning

confidence: 99%

Antioxidants in Nutrition

Jovanović

Simic²

2000

Annals of the New York Academy of Sciences

132

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“…Accordingly, spectroscopic studies have not been surveyed and radiation studies, which result mainly in decarboxylation or deamination of amino acids, have not been incorporated. These aspects of the free-radical chemistry of amino acids have been the subjects of earlier reviews. − Many biochemical reactions involve amino acid radicals . For example, there is strong evidence that free radicals are intermediates in penicillin and cephalosporin biosynthesis − and in the bioconversion of the cyclopropyl amino acid 1 to ethylene during the maturation of fruits.…”

Section: Introductionmentioning

confidence: 99%

Free-Radical Reactions in the Synthesis of α-Amino Acids and Derivatives

1997

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“…Furthermore, it might well be that the skins used in the burial ground were freshly prepared at the time of the burial, so that deterioration due to normal wear had not developed. Since the unsaturated fatty acids apparently are removed by an auto-oxidation process (Jovanovic and Josimovic, 1992) or by polymerization, it seems reasonable to assume that exposure to light, which often occurred during exhibition in the past, would cause variations in the relative abundance of the fatty acids, leading to an increased ratio of the saturated to the unsaturated compounds. The effect of daylight is unambiguously demonstrated by comparing samples H and I, the latter being identical to H as originating from the same skin, except that the hairless side of sample I had been exposed to daylight for about six months at room temperature.…”

Section: Resultsmentioning

confidence: 99%

“…However, exposure to daylight may also influence the fatty acid distribution. In both cases, so-called auto-oxidation appears responsible for the disappearance of the mono-and polyunsaturated fatty acid constituents (Mills, 1966;Jovanovic and Josimovic, 1992). The auto-oxidation leads to lower acids as well as aldehydes.…”

Section: Introductionmentioning

confidence: 99%

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The Preservation of Inuit Clothing Collected during the Fifth Thule Expedition (1921-24)

Carlsen¹,

Feldthus²,

Schmidt³

1995

ARCTIC

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ABSTRACT. Preparation procedures as well as ordinary use apparently cause changes in the appearance of Inuit skin clothing. These changes may alter the inherent properties of skin, such as fatty acid composition and shrinkage temperature. The present paper describes studies of fatty acid distribution and shrinkage temperature in a series of items of Inuit origin collected during the Fifth Thule Expedition (1921 -24). The skins used for the clothing originate from ringed seal (Phoca hispida) and caribou (Rangifer tarandus). For comparison, freshly prepared skins were studied, as were samples of sealskins found in the mummy burial ground in Qilakitsoq, Greenland. It appeared that ordinary use changed the fatty acid distribution to some extent, as well as the shrinkage temperature, indicating slow deterioration. However, more significant deterioration was observed for samples exposed for longer periods to daylight as, for example, when placed on exhibition. The effect of light was verified by studying samples deliberately exposed to full daylight for ca. 6 months. In contrast to these samples, the 500-year-old skins appeared, on the basis of fatty acid distribution and shrinkage temperature, to be in good condition, possibly because of the lack of ordinary use in combination with low storage temperatures.Key words: Inuit, clothing, skin preparation, tanning, seal, caribou, fatty acid, preservation, Fifth Thule Expedition RÉSUMÉ. Les méthodes de préparation ainsi que l'utilisation normale provoquent, semble-t-il, des changements dans l'aspect des vêtements de peau inuit. Ces changements peuvent modifier les propriétés inhérentes de la peau, telles que la répartition des acides gras et la contractilité thermique. Cet article décrit les études portant sur la répartition des acides gras et la contractilité thermique dans une série d'objets d'origine inuit recueillis au cours de la cinquième expédition de Thulé (1921-24). Les peaux servant à l'habillement viennent du phoque annelé (Phoca hispida) et du caribou (Rangifer tarandus). À des fins de comparaison, on a étudié des peaux récemment préparées, ainsi que des échantillons de peaux de phoque trouvées dans le cimetière de momies de Qilakitsoq, au Groenland. Il semble que l'utilisation normale ait changé, dans une certaine mesure, la répartition des acides gras ainsi que la contractilité thermique, indiquant une détérioration lente. On a toutefois observé une détérioration plus importante pour des échantillons exposés durant de plus longues périodes à la lumière naturelle comme, par exemple, lorsqu'ils sont mis en exposition. On a vérifié l'effet de la lumière en étudiant des échantillons délibérément exposés au grand jour pendant environ six mois. Par contraste avec ces échantillons, les peaux de 500 ans semblaient, si l'on se fiait à la répartition des acides gras et à la contractilité thermique, en bon état, et ce, en raison peut-être du manque d'utilisation courante combiné à un entreposage à basse température.

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Radiation chemistry of fatty and amino acids

Cited by 4 publications

References 0 publications

Antioxidants in Nutrition

Antioxidants in Nutrition

Free-Radical Reactions in the Synthesis of α-Amino Acids and Derivatives

The Preservation of Inuit Clothing Collected during the Fifth Thule Expedition (1921-24)

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