On the physiological and cellular homeostasis of ascorbate

Abstract

Recent interest in the role of ascorbate in crucial metabolic processes is driven by the growing number of medical reports that show beneficial effects of ascorbate supplementation for maintaining general well-being and recovery from a variety of medical conditions. The effect of ascorbate on the local body environment highly depends on its local concentration; at low concentrations it can cause the reduction of reactive oxygen and facilitate activities of enzymes, while at high concentrations it generates free radicals by reducing ferric ions. Ascorbate serving as an electron donor assists the iron-containing proteins and the iron transfer between various aqueous compartments. These functions require effective and adjustable mechanisms responsible for ascorbate biodistribution. In the paper we propose a new biophysical model of ascorbate redistribution between various aqueous body compartments. It combines recent experimental evidence regarding the ability of ascorbate to cross the lipid bilayer by unassisted diffusion, with active transport by well-characterized sodium vitamin C transporter (SVCT) membrane proteins. In the model, the intracellular concentration of ascorbate is maintained by the balance of two opposing fluxes: fast active and slow passive transport. The model provides a mechanistic understanding of ascorbate flux across the epidermal barrier in the gut as well as the role of astrocytes in ascorbate recycling in the brain. In addition, ascorbate passive diffusion across biological membranes, which depends on membrane electric potentials and pH gradients, provides the rationale for the correlation between ascorbate distribution and the transfer of iron ions inside a cell. The proposed approach provides, for the first time, a mechanistic account of processes leading to ascorbate physiological and cellular distribution, which helps to explain numerous experimental and clinical observations.

Using decoction of some vitamin C enriched plants for the management of COVID-19 in Jos, Nigeria: A case report

“…Just as honey contains water, fructose, glucose, sucrose, and other sugars, total protein, minerals, acids (such as gluconic acid), vitamins, enzymes, aromas, phenolic compounds, and some minor constituents [20][21][22]. These components including vitamin C are enriched with antioxidants, anti-inflammatory properties that seem to be good and effective remedies against the virus [10,[23][24][25][26] and in some cases against COVID-19 [27] just as vitamin C could be used for the treatment of other diseases [28].…”

Case reports in the use of vitamin C based regimen in prophylaxis and management of COVID-19 among Nigerians

“…It also quells inflammation, cardiovascular diseases, and cancer. All these attributes make it invaluable in the control of COVID-19 [8][9][10][11]. Natural sources of vitamin C in Nigeria include Garcinia kola, Moringa, Guava, Pineapple, Paw-Paw, Citrus fruits, Garlic, Ginger and some others.…”

High-Dose Vitamin C: Preclinical Evidence for Tailoring Treatment in Cancer Patients

“…The second and larger family includes several hydroxylases involved in various functions such as type 1 collagen synthesis, carnitine synthesis, tyrosine catabolism, stability of hypoxia-inducible factor α (HIF-1α) and epigenetic modifications [ 20 , 21 , 22 , 23 ]. The ability to donate one or two electrons makes ascorbate an excellent reducing agent and antioxidant system in humans [ 20 , 24 , 25 , 26 ].…”