Effects of active oxygen scavengers on the peroxidation of linoleic acid catalyzed by dehydro-L-ascorbic acid or its degradation products.

Takagi, Masanosuke; Oda, Hiroshi; Miyamoto, Ikuo; Morita, Naofumi

doi:10.3177/jnsv.34.141

Cited by 7 publications

(3 citation statements)

References 12 publications

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“…It also increased the rate of conjugated-diene formation when added during the propagation phase. Dehydroascorbate decomposes to a wide variety of over 50 degradation products [41], and Takagi et al have shown that dehydroascorbate and 2,3-diketogulonic acid produce free radicals when they degrade and greatly increase the oxidation of linoleic acid, much better than ascorbate does [42]. These free radicals may possibly have been responsible for increasing the modification of the ' fresh ' or moderately oxidized LDL in our experiments.…”

Section: Discussionsupporting

confidence: 45%

The effects of ascorbate and dehydroascorbate on the oxidation of low-density lipoprotein

Stait¹,

Leake

1996

Biochemical Journal

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Ascorbate at concentrations of 60–100 µM inhibits the modification of freshly prepared low-density lipoprotein (LDL) by macrophages. With ‘moderately oxidized’ LDL (produced by prolonged storage in a refrigerator), however, ascorbate does not inhibit LDL modification by macrophages and actually modifies the LDL itself in the absence of macrophages [Stait and Leake (1994) FEBS Lett. 341, 263–267]. We have now shown that dehydroascorbate can modify both ‘fresh’ LDL and moderately oxidized LDL in a dose-dependent manner to increase its uptake by macrophages. The modification of moderately oxidized LDL by ascorbate and dehydroascorbate or of ‘fresh’ LDL by dehydroascorbate is dependent on the presence of iron or copper. In ‘fresh’ LDL, ascorbate inhibited conjugated-diene formation by copper. In moderately oxidized LDL, the number of conjugated dienes present was decreased rapidly in the presence of copper and ascorbate. Dehydroascorbate decreased the lag phase and increased the rate of copper-induced conjugated-diene formation in ‘fresh’ LDL (although in some experiments it inhibited the formation of conjugated dienes). The ascorbate-modified moderately oxidized LDL was taken up by macrophages by their scavenger receptors, as the uptake was inhibited by polyinosinic acid or fucoidan. Ascorbate and dehydroascorbate therefore have the potential to increase LDL oxidation under certain conditions, but whether or not they do so in vivo is unknown.

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Section: Discussionsupporting

confidence: 45%

The effects of ascorbate and dehydroascorbate on the oxidation of low-density lipoprotein

Stait¹,

Leake

1996

Biochemical Journal

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“…‘DKG’ has previously been observed to accelerate the peroxidation of linoleic acid in neutral but not in slightly acidic solutions [49] . A superoxide-scavenging agent, Tiron, suppressed linoleate peroxidation whereas catalase had no inhibitory effect, suggesting that superoxide was the reactive oxygen species (ROS) generated during incubation with DKG.…”

Section: Introductionmentioning

confidence: 99%

Metabolites of 2,3-diketogulonate delay peroxidase action and induce non-enzymic H 2 O 2 generation: Potential roles in the plant cell wall

Kärkönen

Dewhirst

Mackay

et al. 2017

Archives of Biochemistry and Biophysics

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A proportion of the plant's l-ascorbate (vitamin C) occurs in the apoplast, where it and its metabolites may act as pro-oxidants and anti-oxidants. One ascorbate metabolite is 2,3-diketogulonate (DKG), preparations of which can non-enzymically generate H2O2 and delay peroxidase action on aromatic substrates. As DKG itself generates several by-products, we characterised these and their ability to generate H2O2 and delay peroxidase action.DKG preparations rapidly produced a by-product, compound (1), with λmax 271 and 251 nm at neutral and acidic pH respectively. On HPLC, (1) co-eluted with the major H2O2-generating and peroxidase-delaying principle. Compound (1) was slowly destroyed by ascorbate oxidase, and was less stable at pH 6 than at pH 1. Electrophoresis of an HPLC-enriched preparation of (1) suggested a strongly acidic (pKa ≈ 2.3) compound. Mass spectrometry suggested that un-ionised (1) has the formula C6H6O5, i.e. it is a reduction product of DKG (C6H8O7).In conclusion, compound (1) is the major H2O2-generating, peroxidase-delaying principle formed non-enzymically from DKG in the pathway ascorbate → dehydroascorbic acid → DKG → (1). We hypothesise that (1) generates apoplastic H2O2 (and consequently hydroxyl radicals) and delays cell-wall crosslinking — both these effects favouring wall loosening, and possibly playing a role in pathogen defence.

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“…AsA is easily oxidized by active oxygen species, UV light, etc., and the oxidized form of AsA, that is, dehydro-L-ascorbic acid (DHA); is reported to accelerate lipid peroxidation (1,2). The lactone ring of DHA is split rather easily in neutral to alkaline solutions, followed by formations of 2, 3-diketo-L-gulonic acid (DKG) and its further degraded or transformed products, as reported by Otsuka et al (3,4).…”

Section: Discussionmentioning

confidence: 78%

Behavior of 3,4-endiol form of 2,3-diketo-gulono-.DELTA.-lactone formed from dehydro-L-ascorbic acid in deoxygenated and neutral solution.

Takagi

Kawajiri

Nakata

et al. 1989

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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Effects of active oxygen scavengers on the peroxidation of linoleic acid catalyzed by dehydro-L-ascorbic acid or its degradation products.

Cited by 7 publications

References 12 publications

The effects of ascorbate and dehydroascorbate on the oxidation of low-density lipoprotein

The effects of ascorbate and dehydroascorbate on the oxidation of low-density lipoprotein

Metabolites of 2,3-diketogulonate delay peroxidase action and induce non-enzymic H 2 O 2 generation: Potential roles in the plant cell wall

Behavior of 3,4-endiol form of 2,3-diketo-gulono-.DELTA.-lactone formed from dehydro-L-ascorbic acid in deoxygenated and neutral solution.

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