Effect of ascorbic acid (vitamin C) on the ESR spectra of the red and black hair: pheomelanin free radicals are not always present in red hair

2015 ◽  
Vol 53 (12) ◽  
pp. 1019-1023 ◽  
Author(s):  
Eduard Chikvaidze ◽  
Maia Topeshashvili
Keyword(s):  
Ascorbic Acid ◽  
Free Radicals ◽  
Vitamin C ◽  
Esr Spectra ◽  
Black Hair ◽  
Red Hair

Coda

Scurvy ◽  
2018 ◽  
pp. 268-276
Author(s):  
James May ◽  
Fiona Harrison
Keyword(s):  
Ascorbic Acid ◽  
Free Radicals ◽  
Vitamin C ◽  
Physical Symptoms ◽  
Nutritional Deficiencies ◽  
Brain Cells ◽  
Medical Texts ◽  
Vitamin C Deficiency ◽  
Neuroscience Research ◽  
The Brain

This chapter discusses the neurological basis of scurvy. The physical symptoms of extreme vitamin C deficiency, i.e., scurvy, have been described in numerous ships' logs, diaries, and medical texts, stretching back for hundreds of years. Examples include hemorrhage, and the characteristic broken blood vessels under the skin; and hyperkeratosis, or changes in hair such as thinning, alopecia, and corkscrew hairs on the limbs. However, modern techniques in neuroscience research have revealed the highly complex roles of vitamin C in the brain, which may have changed the behavior of those experiencing long periods of nutritional deficiencies. The most important roles for vitamin C, also known as ascorbate and ascorbic acid, are in the synthesis of neurotransmitters, the chemical messengers of the brain, and for protection of neurons (brain cells) against damage by a constant barrage of free radicals.

scholarly journals Vitamin C content of freeze dried pequi (Caryocar brasiliense Camb.) pulp

2018 ◽  
Author(s):  
R. A. Oliveira ◽  
C. T. Soares ◽  
F. G. Nogueira ◽  
A. A. Santana
Keyword(s):  
Ascorbic Acid ◽  
Free Radicals ◽  
Vitamin C ◽  
Whey Protein ◽  
Freeze Drying ◽  
Natural Antioxidant ◽  
Whey Protein Concentrate ◽  
Protein Concentrate ◽  
Freeze Dried ◽  
Caryocar Brasiliense

Vitamin C is one of the constituents of pequi pulp. It is a natural antioxidant, capable of sequestering free radicals. The present study aimed to freeze dry a pequi pulp encapsulated with maltodextrin and whey protein and analyze vitamin C content. Vitamin C loss was lower in the experimental run that did not use encapsulating agent. Whereas, the run that used 15% of whey protein concentrate as encapsulant agent in relation to pequi solids presented the highest value (220.74 mg vitamin C / g pequi solids). Freeze drying of pequi pulp is a technique for vitamin C conservation independently of the variation in maltodextrin and whey protein proportion.Keywords: drying; encapsulating agent; ascorbic acid.

Amperometric assay of vitamin C using an ascorbate oxidase enzyme electrode

1979 ◽  
Vol 44 (11) ◽  
pp. 3395-3404 ◽  
Author(s):  
Pavel Posádka ◽  
Lumír Macholán
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Oxygen Electrode ◽  
Ascorbate Oxidase ◽  
Current Response ◽  
Reaction Conditions ◽  
Long Term Storage ◽  
Oxidase Enzyme ◽  
Optimal Reaction

An oxygen electrode of the Clark type, coated by a thin, active layer of chemically insolubilized ascorbate oxidase from squash peelings specifically detects by measuring oxygen uptake 10 to 400 μg of ascorbic acid in 3 ml of phosphate buffer. The record of current response to substrate addition lasts 1-2 min. The ascorbic acid values determined in various samples of fruit juices are in good agreement with the data obtained by titration and polarography. The suitable composition of the membrane and its lifetime and stability during long-term storage are described; optimal reaction conditions of vitamin C determination and the possibilities of interference of other compounds are also examined. Of the 35 phenols, aromatic amines and acids tested chlorogenic acid only can cause a positive error provided that the enzyme membrane has been prepared from ascorbate oxidase of high purity.

An ESR study of the peroxidase reaction catalyzed by human methaemoglobin and methaemoglobin-haptoglobin complex

1991 ◽  
Vol 56 (4) ◽  
pp. 923-932
Author(s):  
Jana Stejskalová ◽  
Pavel Stopka ◽  
Zdeněk Pavlíček
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Amino Acid ◽  
Peroxidase Activity ◽  
Amino Acid Analysis ◽  
Superoxide Radical ◽  
Esr Spectra ◽  
The Other ◽  
Delocalized Electron

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.

Sign in / Sign up

Export Citation Format

Share Document