Fe&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt; and Fe Nanoparticles by Chemical Reduction of Fe(acac)&lt;sub&gt;3&lt;/sub&gt; by Ascorbic Acid: Role of Water

The ESR spectra of peroxidase systems of methaemoglobin-ascorbic acid-hydrogen peroxide and methaemoglobin-haptoglobin complex-ascorbic acid-hydrogen peroxide have been measured in the acetate buffer of pH 4.5. For the system with methaemoglobin an asymmetrical signal with g ~ 2 has been observed which is interpreted as the perpendicular region of anisotropic spectrum of superoxide radical. On the other hand, for the system with methaemoglobin-haptoglobin complex the observed signal with g ~ 2 is symmetrical and is interpreted as a signal of delocalized electron. After realization of three repeatedly induced peroxidase processes the ESR signal of the perpendicular part of anisotropic spectrum of superoxide radical is distinctly diminished, whereas the signal of delocalized electron remains practically unchanged. An amino acid analysis of methaemoglobin along with results of the ESR measurements make it possible to derive a hypothesis about the role of haptoglobin in increasing of the peroxidase activity of methaemoglobin.

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Ambivalent role of ascorbic acid in the metal-catalyzed oxidation of oligopeptides

Journal of Inorganic Biochemistry ◽

10.1016/j.jinorgbio.2021.111510 ◽

2021 ◽

pp. 111510

Author(s):

Nikolett Bodnár ◽

Katalin Várnagy ◽

Lajos Nagy ◽

Gizella Csire ◽

Csilla Kállay

Keyword(s):

Ascorbic Acid ◽

Metal Catalyzed Oxidation ◽

Metal Catalyzed ◽

Catalyzed Oxidation

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The role of ascorbic acid combined exposure on Imidacloprid-induced oxidative stress and genotoxicity in Nile tilapia

Scientific Reports ◽

10.1038/s41598-021-94020-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Islam M. El-Garawani ◽

Elsayed A. Khallaf ◽

Alaa A. Alne-na-ei ◽

Rehab G. Elgendy ◽

Gaber A. M. Mersal ◽

...

Keyword(s):

Oxidative Stress ◽

Ascorbic Acid ◽

Nile Tilapia ◽

Protective Agent ◽

Strand Breaks ◽

Gill Cells ◽

Significant Amelioration ◽

Neonicotinoid Insecticide ◽

Dna Strand

AbstractImidacloprid (Imid), a systemic neonicotinoid insecticide, is broadly used worldwide. It is reported to contaminate aquatic systems. This study was proposed to evaluate oxidative stress and genotoxicity of Imid on Nile tilapia (Oreochromis niloticus) and the protective effect of ascorbic acid (Asc). O. niloticus juveniles (30.4 ± 9.3 g, 11.9 ± 1.3 cm) were divided into six groups (n = 10/replicate). For 21 days, two groups were exposed to sub-lethal concentrations of Imid (8.75 ppm, 1/20 of 72 h-LC50 and 17.5 ppm, 1/10 of 72 h-LC50); other two groups were exposed to Asc (50 ppm) in combination with Imid (8.75 and 17.5 ppm); one group was exposed to Asc (50 ppm) in addition to a group of unexposed fish which served as controls. Oxidative stress was assessed in the liver where the level of enzymatic activities including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in addition to mRNA transcripts and, Lipid peroxidation (LPO) were evaluated. Moreover, mitotic index (MI) and comet assay were performed, in addition, the erythrocytic micronucleus (MN), and nuclear abnormalities (NA) were observed to assess genotoxicity in fish. Imid exposure induced significant (p ˂ 0.05) changes in the antioxidant profile of the juveniles' liver by increasing the activities and gene expression of SOD, CAT and GPX as well as elevating the levels of LPO. DNA strand breaks in gill cells, erythrocytes and hepatocytes along with erythrocytic MN and NA were also significantly elevated in Imid-exposed groups. MI showed a significant (p ˂ 0.05) decrease associated with Imid exposure. Asc administration induced a significant amelioration towards the Imid toxicity (8.75 and 17.5 ppm). A significant protective potency against the genotoxic effects of Imid was evidenced in Asc co-treated groups. Collectively, results highlight the importance of Asc as a protective agent against Imid-induced oxidative stress and genotoxicity in O. niloticus juveniles.

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Vitamin C—Sources, Physiological Role, Kinetics, Deficiency, Use, Toxicity, and Determination

Nutrients ◽

10.3390/nu13020615 ◽

2021 ◽

Vol 13 (2) ◽

pp. 615

Author(s):

Martin Doseděl ◽

Eduard Jirkovský ◽

Kateřina Macáková ◽

Lenka Krčmová ◽

Lenka Javorská ◽

...

Keyword(s):

Ascorbic Acid ◽

Vitamin C ◽

Iron Absorption ◽

Plasma Concentrations ◽

Physiological Role ◽

Renal Stones ◽

Anti Oxidant ◽

High Doses ◽

Epigenetic Processes

Vitamin C (L-ascorbic acid) has been known as an antioxidant for most people. However, its physiological role is much larger and encompasses very different processes ranging from facilitation of iron absorption through involvement in hormones and carnitine synthesis for important roles in epigenetic processes. Contrarily, high doses act as a pro-oxidant than an anti-oxidant. This may also be the reason why plasma levels are meticulously regulated on the level of absorption and excretion in the kidney. Interestingly, most cells contain vitamin C in millimolar concentrations, which is much higher than its plasma concentrations, and compared to other vitamins. The role of vitamin C is well demonstrated by miscellaneous symptoms of its absence—scurvy. The only clinically well-documented indication for vitamin C is scurvy. The effects of vitamin C administration on cancer, cardiovascular diseases, and infections are rather minor or even debatable in the general population. Vitamin C is relatively safe, but caution should be given to the administration of high doses, which can cause overt side effects in some susceptible patients (e.g., oxalate renal stones). Lastly, analytical methods for its determination with advantages and pitfalls are also discussed in this review.

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