scholarly journals The non-oxidative degradation of ascorbic acid at physiological conditions

2000 ◽  
Vol 1501 (1) ◽  
pp. 12-24 ◽  
Author(s):  
Gregory L.W Simpson ◽  
B.J Ortwerth
Keyword(s):  
Ascorbic Acid ◽  
Oxidative Degradation ◽  
Physiological Conditions

Ascorbic Acid Catalyzes Nitric Oxide Production from Nitrite Ions.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1574-1574 ◽  
Author(s):  
Nathawut Sibmooh ◽  
Barbora Piknova ◽  
Alan N. Schechter
Keyword(s):  
Nitric Oxide ◽  
Ascorbic Acid ◽  
Rate Constant ◽  
Dehydroascorbic Acid ◽  
Nitrite Reduction ◽  
Erythrocyte Membranes ◽  
No Production ◽  
Ferrous Ions ◽  
Physiological Conditions ◽  
Ferrous Heme

Abstract We have previously shown that nitrite ions can be reduced by hemoglobin to nitric oxide (NO), a ubiquitous signaling molecule and potent vasodilator. Nitrite serves as a stable tissue and vascular source for NO production; the reduction reaction is maximal at about 50% oxygen saturation values and is enhanced at low pH but little is known about other effectors of this reaction. In the current work, we studied the effect of ascorbic acid on nitrite reduction under physiological conditions using chemiluminescence to quantify NO production. In physiological buffer, this reaction has a rate constant of about 1×10−5 M−1.s−1. Thus, a significant production of NO would likely occur in plasma only at pharmacological levels of ascorbic acid (> 1 mM) although lowering pH below 7.0 markedly enhances this reaction. Loading human erythrocytes with 0.5 mM dehydroascorbic acid, which is in redox equilibrium with ascorbic acid and which can significantly raise intracellular ascorbic acid levels, increased basal levels of nitrite ions from 42±9.0 nM to 98±56 nM. Uptake of nitrite ions into erythrocytes by incubation in 10 μM nitrite was increased about 1.5 fold by dehydroascorbic acid and the half-time of nitrite loss was slowed to the same extent. Ascorbic acid also reduced free ferric heme in erythrocytes and plasma to ferrous heme which catalyzed the reduction of nitrite to NO with a rate constant of 2.3×103 M−1.s−1 under physiological conditions. However, free ferrous ions did not significantly produce NO in physiological buffer (rate constant = 1.8×10−2 M−1.s−1). The reaction of ferrous heme with nitrite was not affected by heme binding to proteins such as hemopexin and albumin, or erythrocyte membranes. These results suggest that physiological levels of ascorbic acid (20–80 μM in plasma and erythrocytes) may act to catalyze NO production in the blood by promoting the reduction of nitrite ions by free ferrous heme and by increasing intra-erythrocytic levels of nitrite ions which can be reduced to NO by deoxyhemoglobin.

scholarly journals Exogenous ascorbic acid is a pro-nitrant in Arabidopsis thaliana

2019 ◽  
Vol 62 (2) ◽  
pp. 115-122
Author(s):  
Gábor Feigl ◽  
Ádám Bordé ◽  
Árpád Molnár ◽  
Zsuzsanna Kolbert
Keyword(s):  
Ascorbic Acid ◽  
Reactive Nitrogen Species ◽  
Redox State ◽  
Plant Biology ◽  
Wild Type ◽  
Physiological Conditions ◽  
Redox Active ◽  
Tight Correlation ◽  
Mutant Lines ◽  
First Time

Due to the intensified production of reactive nitrogen species (RNS) proteins can be modified by tyrosine nitration (PTN). Examination of PTN is a hot topic of plant biology, especially because the exact outcome of this modification is still pending. Both RNS and ascorbic acid (AsA) are redox-active molecules, which directly affect the redox state of cells. The possible link between RNS-dependent PTN and AsA metabolism was studied in RNS (gsnor1-3, nia1nia2) and AsA (vtc2-3) homeostasis Arabidopsis mutants. During physiological conditions, intensified PTN was detected in all mutant lines compared to the wild-type (WT); without altering nitration pattern. Moreover, the increased PTN seemed to be associated with endogenous peroxynitrite (ONOO-) levels, but it showed no tight correlation with endogenous levels of nitric-oxide (NO) or AsA. Exogenous AsA caused intensified PTN in WT, vtc2-3 and nia1nia2. In the background of increased PTN, significant NO and ONOO- accumulation was detected, indicating exogenous AsA-induced RNS burst. Interestingly, in AsA-triggered stress-situation, changes of NO levels seem to be primarily connected to the development of PTN. Our results point out for the first time that similarly to human and animal systems exogenous AsA exerts pro-nitrant effect on plant proteome.

scholarly journals Therapeutic Perspective of Vitamin C and Its Derivatives

Antioxidants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 247 ◽  
Author(s):  
Meščić Macan ◽  
Gazivoda Kraljević ◽  
Raić-Malić
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Essential Role ◽  
Structural Motif ◽  
Oxygen Species ◽  
Physiological Conditions ◽  
Cellular Processes ◽  
Cellular Oxidation ◽  
Cellular Components ◽  
Therapeutic Perspective

L-Ascorbic acid (ASA), vitamin C, is a ubiquitous carbohydrate-like compound that has an essential role in a number of cellular processes, such as collagen synthesis, cellular oxidation, and various hydroxylation reactions. ASA is a biomolecule of critical importance for protection of cellular components against oxidative damage caused by toxic free radicals and other reactive oxygen species (ROS) that are involved in the development of various types of chronic diseases. Vitamin C has a switchover role from being an antioxidant in physiological conditions to a prooxidant under pathologic conditions. Moreover, some l-ascorbic acid derivatives exhibit strong and selective antitumor and antiviral activity. This review emphasizes the advances on diverse and potent biological profiles of l-ascorbic acid and its derivatives, and their perspective in the development of new bioactive chemical entities in the future. The work is primarily addressed at antioxidant, anticancer, and antiviral potencies of l-ascorbic acid and compounds containing its butenolide structural motif.

ChemInform Abstract: 6-Deoxy-6-fluoro-L-ascorbic Acid: Crystal Structure and Oxidative Degradation.

ChemInform ◽  
2001 ◽  
Vol 32 (4) ◽  
pp. no-no
Author(s):  
Janusz Madaj ◽  
Yoko Nishikawa ◽  
V. Prakash Reddy ◽  
Peter Rinaldi ◽  
Tadao Kurata ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ascorbic Acid ◽  
Oxidative Degradation ◽  
Acid Crystal

scholarly journals Oxidative degradation of haemoglobin by nitrosobenzene in the erythrocyte

1978 ◽  
Vol 174 (3) ◽  
pp. 693-697 ◽  
Author(s):  
K Hirota ◽  
H A Itano ◽  
T S Vedvick
Keyword(s):  
Ascorbic Acid ◽  
Benzene Ring ◽  
Oxidative Degradation ◽  
Oxidative Cleavage ◽  
Oxidative Conversion ◽  
Active Intermediate

Substitutions on the benzene ring of nitrosobenzene did not have the same effect on oxidative haemolysis as substitutions on phenylhydrazine. We previously found that the haemolytic effect of arylhydrazines paralleled their oxidative conversion into ligands of ferrihaemoglobin. In contrast, although most substituted nitrosobenzenes that are ligands of ferrohaemoglobin caused haemolysis and most that are not ligands failed to cause nitrosoarenes appeared to be related more closely to the ease of their reduction to arylhydroxylamines than to their properties as ligands. We propose a mechanism of oxidative degradation whereby the cyclic formation of phenylhydroxylamine from nitrosobenzene within an erythrocyte leads to the accumulation of H2O2, which then reacts with ferrohaemoglobin to initiate the oxidative cleavage of haem. The posulated active intermediate in this reaction is the same as that previously proposed in the oxidative degradation of haemoglobin by phenylhydrzine and in the coupled oxidation of ascorbic acid and haemoglobin.

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