Superoxide ion as a primary reductant in ascorbate-mediated ferretin iron release

Boyer, Rodney F.; McCleary, Craig J.

doi:10.1016/0891-5849(87)90017-7

Cited by 151 publications

(85 citation statements)

References 38 publications

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“…As in the present work, the effect was enhanced when cells were pre-incubated with Our data suggest that AA exacerbates H 2 O 2 -induced DNA damage and cell injury by increasing the availability of catalytically active iron. Notably, we have observed an increase in the LIP in the absence of added exogenous iron, which suggests that AA may mobilize endogenous iron by reducing ferric to ferrous iron and assisting in its diffusion Vitamin C, DNA damage and iron homeostasis 19 from sites of iron storage, such as cellular ferritin, into the LIP [52]. The changes in the expression of ferritin and TfR reported herein further suggest that AA affects iron homeostasis in human cells by increasing the levels of intracellular bioavailable iron.…”

Section: Discussionmentioning

confidence: 65%

Vitamin C modulation of H2O2-induced damage and iron homeostasis in human cells

Duarte

Jones

2007

Free Radical Biology and Medicine

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Vitamin C (ascorbic acid, AA) is an important antioxidant in human plasma. It is clear, however, that AA has other important, non-antioxidant roles in cells. Of particular interest is its involvement in iron metabolism, since AA enhances dietary iron absorption, increases the activity of Fe 2+ -dependent cellular enzymes, promotes Fenton reactions in vitro and was reported to have deleterious effects in individuals with iron overload. Nevertheless, the ability of AA to modulate iron metabolism and enhance iron-dependent damage in cells, tissues and organisms has not been fully elucidated. Here we investigated the effect of AA on iron-mediated oxidative stress in normal human fibroblasts. Incubation with physiologically relevant concentrations of AA was not harmful but sensitised cells towards H 2 O 2 -induced, iron-dependent DNA strand breakage and cell death. We also report that AA increased the levels of intracellular catalytic iron and concomitantly modulated the expression of two wellestablished iron-regulated genes, ferritin and transferrin receptor. In summary, we present evidence of a novel, non-antioxidant role of AA in human cells, where it increases iron availability and enhances ROS-mediated, iron-dependent damage. We suggest that AA may exacerbate the deleterious effects of metals in vivo and promote normal tissue injury in situations associated with elevated ROS production.

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Section: Discussionmentioning

confidence: 65%

Vitamin C modulation of H2O2-induced damage and iron homeostasis in human cells

Duarte

Jones

2007

Free Radical Biology and Medicine

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“…The chelating activity towards Fe 2+ was measured by the method of Boyer and McCleary (1987) with a slight modification. Sample (940 μl) was mixed with 20 μl of 2 mM FeCl 2 and 40 μl of 5 mM ferrozine.…”

Section: Chelating Activity On Ferrous Ions (Fe 2+ )mentioning

confidence: 99%

Antioxidant activities of lead (Leucaena leucocephala) seed as affected by extraction solvent, prior dechlorophyllisation and drying methods

et al. 2012

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Extracts of brown lead (Leucaena leucocephala) seed prepared using different extraction solvents were determined for antioxidative activities using different assays. The highest yield (3.4-4.0%) was obtained when water was used as an extraction solvent, compared with all ethanolic extracts used (1.2-2.0 %) (P<0.05). Much lower chlorophyll content was found in the water extract. When hot water was used, the resulting extract contained lower total phenolic and mimosine contents (P<0.05). In general, 60-80 % ethanolic extracts had higher 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities, ferric reducing antioxidant power (FRAP) and metal chelating activity than water extracts (P<0.05). When brown lead seed was dechlorophyllised prior to extraction, the water extract had slightly increased yield with lower chlorophyll content. Nevertheless, prior chlorophyll removal resulted in the increase in antioxidative activities but lower total phenolic and mimosine contents (P<0.05). Generally, phenolic compounds and mimosine were more released when water was used as the extraction solvent, while the lower amount of chlorophyll was extracted. Oven-drying exhibited the negative effect on antioxidative activities and mimosine content. The higher antioxidative activities with concomitant higher total phenolic and mimosine contents were found in water extract dried by freeze drying. Thus, extraction solvent, dechlorophyllisation and drying methods directly influenced the yield and antioxidative activity of lead seed extract.

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“…6-OHDA [18], reactive oxgen species like superoxide anion [19,20], nitric oxide [20,21] and substances normally active as antioxidants like glutathione [22,23] and ascorbate [22].…”

Section: Introductionmentioning

confidence: 99%

Mobilization of iron from cellular ferritin by ascorbic acid in neuroblastoma SK‐N‐SH cells: an EPR study

Baader¹,

Bill²,

Trautwein³

et al. 1996

FEBS Letters

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The mobifization of iron from intracellular ferritin by ascorbic acid has been analysed in sltu by electron paramagentic resonance (EPR) spectroscopy. EPR enables a distinction between ferritins and other Fe3+-binding cellular components. The ordered iron core of ferritin gives rise to a resonance signal which can be observed only at temperatures above 50 K. In the present study we clearly demonstrate that ascorblc acid is capable of mobilizing iron from ferritin in the cellular system by reduction of the ferric ion core in neuroblastoma SK-N-SH cells. This mechanism may open new ways in the therapy of this hardly curable tumor in stage IV, especially in combination with some cytostatic drugs.

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Superoxide ion as a primary reductant in ascorbate-mediated ferretin iron release

Cited by 151 publications

References 38 publications

Vitamin C modulation of H2O2-induced damage and iron homeostasis in human cells

Vitamin C modulation of H2O2-induced damage and iron homeostasis in human cells

Antioxidant activities of lead (Leucaena leucocephala) seed as affected by extraction solvent, prior dechlorophyllisation and drying methods

Mobilization of iron from cellular ferritin by ascorbic acid in neuroblastoma SK‐N‐SH cells: an EPR study

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