Component

Ascorbyl radical

One-electron-oxidized ascorbate radical, distinct from two-electron-oxidized DHA.

7 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What acts on it

  1. Coupling bovine DBH tyramine hydroxylation to semidehydroascorbate reductase identified semidehydroascorbate as the immediate enzymic oxidation product of ascorbate.

    L-Ascorbate → Ascorbyl radical source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Vitamin C chemistry in collagen, modified-lysine/carnitine metabolism or copper-dependent peptide/catecholamine processing.
    experimental_model
    Purified bovine DBH coupled to rat-liver or Neurospora semidehydroascorbate reductase
    exposure
    Tyramine beta-hydroxylation with ascorbate; coupled pyridine-nucleotide oxidation and radical recycling assays.
    limitations
    Heterologous reductase-coupled assay; radical dismutation can subsequently produce DHA, so immediate product and net redox balance must be distinguished.
    nutrient_topic
    Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C
    organism
    Bos taurus; Rattus norvegicus; Neurospora crassa
    plain_language
    This copper enzyme takes single electrons from vitamin C, leaving an ascorbyl radical that can be recycled.
    primary_references
    [dbh1981] Mechanism of dopamine-beta-hydroxylation. Semidehydroascorbate as the enzyme oxidation product of ascorbate. (1981). https://pubmed.ncbi.nlm.nih.gov/6451628/ DOI: 10.1016/S0021-9258(19)69620-1
    tissue_or_cell_type
    Bovine adrenal-medullary enzyme plus heterologous reductase preparations

    Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 807–818

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified bovine DBH coupled to rat-liver or Neurospora semidehydroascorbate reductase · source_derived_draft · unverified_draft

    ### vc-enzyme-dbh-radical-product Coupling bovine DBH tyramine hydroxylation to semidehydroascorbate reductase identified semidehydroascorbate as the immediate enzymic oxidation product of ascorbate. Condition category: normal nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: This copper enzyme takes single electrons from vitamin C, leaving an ascorbyl radical that can be recycled. organism: Bos taurus; Rattus norvegicus; Neurospora crassa tissue_or_cell_type: Bovine adrenal-medullary enzyme plus heterologous reductase preparations experimental_model: Purified bovine DBH coupled to rat-liver or Neurospora semidehydroascorbate reductase limitations: Heterologous reductase-coupled assay; radical dismutation can subsequently produce DHA, so immediate product and net redox balance must be distinguished. cross_nutrient: Vitamin C chemistry in collagen, modified-lysine/carnitine metabolism or copper-dependent peptide/catecholamine processing. exposure: Tyramine beta-hydroxylation with ascorbate; coupled pyridine-nucleotide oxidation and radical recycling assays. [dbh1981] Mechanism of dopamine-beta-hydroxylation. Semidehydroascorbate as the enzyme oxidation product of ascorbate. (1981). https://pubmed.ncbi.nlm.nih.gov/6451628/ DOI: 10.1016/S0021-9258(19)69620-1
    Complete structured claim and evidence

  2. Purified rat liver thioredoxin reductase decreased ascorbyl radical measured by electron paramagnetic resonance while consuming NADPH; DHA controls could not explain the signal.

    Rat thioredoxin reductase 1 / Txnrd1 → Ascorbyl radical source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    true
    experimental_model
    Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats
    exposure
    Low-micromolar ascorbyl radical generated by ascorbate oxidase
    limitations
    Purified assay; radical and DHA reduction are distinct reactions.
    nutrient_topic
    Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C
    organism
    Rattus norvegicus
    plain_language
    The reductase can also recycle the one-electron vitamin C radical.
    primary_references
    [may1998] Reduction of the ascorbyl free radical to ascorbate by thioredoxin reductase. (1998). https://pubmed.ncbi.nlm.nih.gov/9722529/ DOI: 10.1074/jbc.273.36.23039
    tissue_or_cell_type
    Purified liver enzyme

    Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 416–427

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats · source_derived_draft · unverified_draft

    ### vc-transport-txnrd-radical Purified rat liver thioredoxin reductase decreased ascorbyl radical measured by electron paramagnetic resonance while consuming NADPH; DHA controls could not explain the signal. Condition category: normal nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: The reductase can also recycle the one-electron vitamin C radical. organism: Rattus norvegicus tissue_or_cell_type: Purified liver enzyme experimental_model: Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats limitations: Purified assay; radical and DHA reduction are distinct reactions. exposure: Low-micromolar ascorbyl radical generated by ascorbate oxidase cross_nutrient: true [may1998] Reduction of the ascorbyl free radical to ascorbate by thioredoxin reductase. (1998). https://pubmed.ncbi.nlm.nih.gov/9722529/ DOI: 10.1074/jbc.273.36.23039
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. In pulse-radiolysis assays, ascorbate rapidly reduced the one-electron-oxidized ergothioneine transient back toward ergothioneine, forming ascorbyl radicals.

    L-Ascorbate → Ergothioneine one-electron oxidation transient source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Cell-free reaction; reported rate constant 6.3 x 10^8 M^-1 s^-1.
    limitations
    Chemical kinetics do not establish tissue flux or a required supplement combination.
    nutrient_topic
    Ergothioneine collection; molecular form, preparation, species, exposure and manipulation remain explicit. · L-Ergothioneine
    plain_language
    Vitamin C can repair an oxidized ergothioneine intermediate.
    primary_references
    One-electron oxidation of ergothioneine and analogues investigated by pulse radiolysis: redox reaction involving ergothioneine and vitamin C. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8615839/ · DOI 10.1042/bj3150625

    Ergothioneine: transport, redox chemistry and cross-nutrient mechanisms (2026-09-19) · lines 112–118

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Cell-free reaction; reported rate constant 6.3 x 10^8 M^-1 s^-1. · source_derived_draft · unverified_draft

    ## ergothioneine-ascorbate-repair Vitamin C can repair an oxidized ergothioneine intermediate. In pulse-radiolysis assays, ascorbate rapidly reduced the one-electron-oxidized ergothioneine transient back toward ergothioneine, forming ascorbyl radicals. Model: Cell-free reaction; reported rate constant 6.3 x 10^8 M^-1 s^-1. Limitations: Chemical kinetics do not establish tissue flux or a required supplement combination. Evidence access: Primary abstract One-electron oxidation of ergothioneine and analogues investigated by pulse radiolysis: redox reaction involving ergothioneine and vitamin C. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8615839/ · DOI 10.1042/bj3150625
    Complete structured claim and evidence

  2. In RPMI/FCS exposed to 5 mM ascorbate, added 5 µM FAC iron accelerated oxygen consumption/ascorbate oxidation but reduced detectable peroxide accumulation, showing that faster oxidation need not yield a larger steady peroxide pool.

    Ferric ammonium citrate → Extracellular hydrogen peroxide accumulation source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    true
    evidence_location
    Figure 2a–b; Oximetry Methods
    experimental_model
    Cell-free medium oximetry; peroxide inferred from catalase-triggered oxygen release
    exposure
    5 mM ascorbate ±5 µM FAC iron; oxygen trace and 600 U catalase addition after about 15 min.
    limitations
    FAC supplementation changes iron speciation as well as concentration; matching plasma total iron does not reconstruct transferrin binding or tissue interstitial chemistry. No clinical efficacy conclusion. The endpoint measures net peroxide and does not separately determine every elementary redox rate.
    nutrient_topic
    Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C
    organism
    Cell-free bovine-serum-containing medium
    plain_language
    Iron sped up vitamin C oxidation while also helping remove the peroxide produced.
    primary_references
    [c-reg-mojic] Extracellular iron diminishes anticancer effects of vitamin C: an in vitro study. (2014). https://pubmed.ncbi.nlm.nih.gov/25092529/ DOI: 10.1038/srep05955
    tissue_or_cell_type
    RPMI-1640 +10% FCS

    Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1299–1311

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Cell-free medium oximetry; peroxide inferred from catalase-triggered oxygen release · source_derived_draft · unverified_draft

    ### c-reg-extracellular-iron-peroxide-removal In RPMI/FCS exposed to 5 mM ascorbate, added 5 µM FAC iron accelerated oxygen consumption/ascorbate oxidation but reduced detectable peroxide accumulation, showing that faster oxidation need not yield a larger steady peroxide pool. Condition category: normal nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: Iron sped up vitamin C oxidation while also helping remove the peroxide produced. organism: Cell-free bovine-serum-containing medium tissue_or_cell_type: RPMI-1640 +10% FCS experimental_model: Cell-free medium oximetry; peroxide inferred from catalase-triggered oxygen release limitations: FAC supplementation changes iron speciation as well as concentration; matching plasma total iron does not reconstruct transferrin binding or tissue interstitial chemistry. No clinical efficacy conclusion. The endpoint measures net peroxide and does not separately determine every elementary redox rate. exposure: 5 mM ascorbate ±5 µM FAC iron; oxygen trace and 600 U catalase addition after about 15 min. cross_nutrient: true evidence_location: Figure 2a–b; Oximetry Methods [c-reg-mojic] Extracellular iron diminishes anticancer effects of vitamin C: an in vitro study. (2014). https://pubmed.ncbi.nlm.nih.gov/25092529/ DOI: 10.1038/srep05955
    Complete structured claim and evidence

  3. Ascorbate produced peroxide in cell culture medium without requiring cells; accumulation depended on ascorbate concentration, time and serum fraction, and tracked ascorbyl radical detected by EPR.

    L-Ascorbate → Extracellular hydrogen peroxide accumulation source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    false
    evidence_location
    Figure 4A–C
    experimental_model
    Cell-free medium; catalase-dependent oxygen-electrode peroxide assay and EPR
    exposure
    0.2–2 mM ascorbate over 1 h; 2 mM ascorbate with 0.5–10% FBS in serum-dependence experiment.
    limitations
    Pharmacological in-vitro exposure; medium chemistry and peroxide clearance differ from intact tissues. No dietary or clinical anticancer inference. Net accumulation reflects both production and removal; ascorbate can interfere with routine peroxidase assays.
    nutrient_topic
    Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C
    organism
    Cell-free; bovine serum-containing medium
    plain_language
    The culture liquid itself could turn high-concentration vitamin C into peroxide.
    primary_references
    [c-reg-chen] Pharmacologic ascorbic acid concentrations selectively kill cancer cells: action as a pro-drug to deliver hydrogen peroxide to tissues. (2005). https://pubmed.ncbi.nlm.nih.gov/16157892/ DOI: 10.1073/pnas.0506390102
    tissue_or_cell_type
    Extracellular assay medium

    Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1257–1269

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Cell-free medium; catalase-dependent oxygen-electrode peroxide assay and EPR · source_derived_draft · unverified_draft

    ### c-reg-medium-peroxide-generation Ascorbate produced peroxide in cell culture medium without requiring cells; accumulation depended on ascorbate concentration, time and serum fraction, and tracked ascorbyl radical detected by EPR. Condition category: normal nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: The culture liquid itself could turn high-concentration vitamin C into peroxide. organism: Cell-free; bovine serum-containing medium tissue_or_cell_type: Extracellular assay medium experimental_model: Cell-free medium; catalase-dependent oxygen-electrode peroxide assay and EPR limitations: Pharmacological in-vitro exposure; medium chemistry and peroxide clearance differ from intact tissues. No dietary or clinical anticancer inference. Net accumulation reflects both production and removal; ascorbate can interfere with routine peroxidase assays. exposure: 0.2–2 mM ascorbate over 1 h; 2 mM ascorbate with 0.5–10% FBS in serum-dependence experiment. cross_nutrient: false evidence_location: Figure 4A–C [c-reg-chen] Pharmacologic ascorbic acid concentrations selectively kill cancer cells: action as a pro-drug to deliver hydrogen peroxide to tissues. (2005). https://pubmed.ncbi.nlm.nih.gov/16157892/ DOI: 10.1073/pnas.0506390102
    Complete structured claim and evidence

  4. Rat liver microsomes reduced ascorbyl radical using NADH, and this activity was insensitive to selenium depletion.

    NADH → Ascorbyl radical reduction to ascorbate source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    true
    experimental_model
    Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats
    exposure
    Control and selenium-deficient rat liver microsome assays
    limitations
    Responsible microsomal enzyme was not established in the abstract; do not assign the activity to TXNRD1.
    nutrient_topic
    Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C
    organism
    Rattus norvegicus
    plain_language
    A membrane-associated recycling route remained active despite selenium shortage.
    primary_references
    [may1998] Reduction of the ascorbyl free radical to ascorbate by thioredoxin reductase. (1998). https://pubmed.ncbi.nlm.nih.gov/9722529/ DOI: 10.1074/jbc.273.36.23039
    tissue_or_cell_type
    Liver microsomal fraction
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 442–453

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats · source_derived_draft · unverified_draft

    ### vc-transport-microsomal-radical Rat liver microsomes reduced ascorbyl radical using NADH, and this activity was insensitive to selenium depletion. Condition category: nutrient_deficiency nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: A membrane-associated recycling route remained active despite selenium shortage. organism: Rattus norvegicus tissue_or_cell_type: Liver microsomal fraction experimental_model: Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats limitations: Responsible microsomal enzyme was not established in the abstract; do not assign the activity to TXNRD1. exposure: Control and selenium-deficient rat liver microsome assays cross_nutrient: true [may1998] Reduction of the ascorbyl free radical to ascorbate by thioredoxin reductase. (1998). https://pubmed.ncbi.nlm.nih.gov/9722529/ DOI: 10.1074/jbc.273.36.23039
    Complete structured claim and evidence

  5. Dialyzed liver cytosol from selenium-deficient rats lost NADPH-dependent ascorbyl-radical reducing activity attributed to thioredoxin reductase.

    Selenium → Ascorbyl radical reduction to ascorbate source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    true
    experimental_model
    Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats
    exposure
    Dietary selenium depletion; isolated dialyzed cytosol
    limitations
    Activity assignment also used inhibitor sensitivity; this is a fraction assay, not a direct human outcome.
    nutrient_topic
    Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C
    organism
    Rattus norvegicus
    plain_language
    Selenium deficiency impaired radical recycling in the rat liver’s soluble fraction.
    primary_references
    [may1998] Reduction of the ascorbyl free radical to ascorbate by thioredoxin reductase. (1998). https://pubmed.ncbi.nlm.nih.gov/9722529/ DOI: 10.1074/jbc.273.36.23039
    tissue_or_cell_type
    Liver cytosol
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 429–440

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats · source_derived_draft · unverified_draft

    ### vc-transport-selenium-cytosolic-radical Dialyzed liver cytosol from selenium-deficient rats lost NADPH-dependent ascorbyl-radical reducing activity attributed to thioredoxin reductase. Condition category: nutrient_deficiency nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: Selenium deficiency impaired radical recycling in the rat liver’s soluble fraction. organism: Rattus norvegicus tissue_or_cell_type: Liver cytosol experimental_model: Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats limitations: Activity assignment also used inhibitor sensitivity; this is a fraction assay, not a direct human outcome. exposure: Dietary selenium depletion; isolated dialyzed cytosol cross_nutrient: true [may1998] Reduction of the ascorbyl free radical to ascorbate by thioredoxin reductase. (1998). https://pubmed.ncbi.nlm.nih.gov/9722529/ DOI: 10.1074/jbc.273.36.23039
    Complete structured claim and evidence

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

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