Component

Coumarin 7-hydroxylation

Coumarin 7-hydroxylation. Species, exposure and limitations are retained in each linked claim.

6 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. Cytochrome b5 increased CYP2A6-mediated coumarin hydroxylation; kinetic experiments supported electron transfer to the oxygenated enzyme.

    Cytochrome b5 preparation used in the 2005 CYP2A6 kinetic experiment; species not resolved in abstract → Coumarin 7-hydroxylation source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/coumarin-research/15665333.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "79f42118f337ffe818b92138941685126173355131f8e12ca7cae9a437800a5b", "start_char": 0, "end_char": 1689, "text_sha256": "79f42118f337ffe818b92138941685126173355131f8e12ca7cae9a437800a5b"}
    experimental_model
    Purified human CYP2A6 kinetic experiments
    exposure
    Coumarin oxidation; stopped-flow and steady-state kinetics, selected measures at 23 C
    limitations
    Biochemical rates do not measure whole-body clearance; accessory b5 species is not specified in the abstract.
    nutrient_topic
    Coumarin research collection; topical membership is not evidence of a direct dietary effect. · Coumarin
    organism
    Human CYP2A6 with reconstituted accessory proteins
    plain_language
    An accessory electron carrier improved the enzyme reaction.
    primary_references
    [coumarin-p15665333] Kinetic analysis of oxidation of coumarins by human cytochrome P450 2A6. (2005). https://pubmed.ncbi.nlm.nih.gov/15665333/ DOI: 10.1074/jbc.m411019200
    tissue_or_cell_type
    Reconstituted enzyme system

    Coumarin: metabolism, signaling and nutrient connections (2026-09-17) · lines 150–161

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified human CYP2A6 kinetic experiments · source_derived_draft · unverified_draft

    ### coumarin-b5-enhancement Cytochrome b5 increased CYP2A6-mediated coumarin hydroxylation; kinetic experiments supported electron transfer to the oxygenated enzyme. Condition category: normal nutrient_topic: Coumarin research collection; topical membership is not evidence of a direct dietary effect. plain_language: An accessory electron carrier improved the enzyme reaction. organism: Human CYP2A6 with reconstituted accessory proteins tissue_or_cell_type: Reconstituted enzyme system experimental_model: Purified human CYP2A6 kinetic experiments limitations: Biochemical rates do not measure whole-body clearance; accessory b5 species is not specified in the abstract. exposure: Coumarin oxidation; stopped-flow and steady-state kinetics, selected measures at 23 C evidence_span: {"source_cache": "artifacts/coumarin-research/15665333.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "79f42118f337ffe818b92138941685126173355131f8e12ca7cae9a437800a5b", "start_char": 0, "end_char": 1689, "text_sha256": "79f42118f337ffe818b92138941685126173355131f8e12ca7cae9a437800a5b"} [coumarin-p15665333] Kinetic analysis of oxidation of coumarins by human cytochrome P450 2A6. (2005). https://pubmed.ncbi.nlm.nih.gov/15665333/ DOI: 10.1074/jbc.m411019200
    Complete structured claim and evidence

  2. CYP2A6 variant alleles were identified in individuals with poor coumarin metabolism, including a single-amino-acid inactivating variant.

    CYP2A6 variant alleles in the 1995 coumarin phenotyping study; original nomenclature retained → Coumarin 7-hydroxylation source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_span
    {"source_cache": "artifacts/coumarin-research/7668294.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "aeb377e6bbda1a552066c5d1caf1bf558753096627b863835637a0f2f942b3b1", "start_char": 0, "end_char": 1316, "text_sha256": "aeb377e6bbda1a552066c5d1caf1bf558753096627b863835637a0f2f942b3b1"}
    experimental_model
    CYP2A gene sequencing and coumarin metabolic phenotyping
    exposure
    Original CYP2A6v1/v2 nomenclature; poor-metabolizer individuals
    limitations
    Historical variant labels retained; no automatic mapping to modern star alleles and no demonstrated prediction of liver injury.
    nutrient_topic
    Coumarin research collection; topical membership is not evidence of a direct dietary effect. · Coumarin
    organism
    Human
    plain_language
    Inherited enzyme differences can change how coumarin is processed.
    primary_references
    [coumarin-p7668294] A genetic polymorphism in coumarin 7-hydroxylation: sequence of the human CYP2A genes and identification of variant CYP2A6 alleles. (1995). https://pubmed.ncbi.nlm.nih.gov/7668294/
    tissue_or_cell_type
    Genomic DNA and whole-body probe metabolism
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Coumarin: metabolism, signaling and nutrient connections (2026-09-17) · lines 631–642

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · CYP2A gene sequencing and coumarin metabolic phenotyping · source_derived_draft · unverified_draft

    ### coumarin-genetic-variation CYP2A6 variant alleles were identified in individuals with poor coumarin metabolism, including a single-amino-acid inactivating variant. Condition category: machinery_impairment nutrient_topic: Coumarin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Inherited enzyme differences can change how coumarin is processed. organism: Human tissue_or_cell_type: Genomic DNA and whole-body probe metabolism experimental_model: CYP2A gene sequencing and coumarin metabolic phenotyping limitations: Historical variant labels retained; no automatic mapping to modern star alleles and no demonstrated prediction of liver injury. exposure: Original CYP2A6v1/v2 nomenclature; poor-metabolizer individuals evidence_span: {"source_cache": "artifacts/coumarin-research/7668294.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "aeb377e6bbda1a552066c5d1caf1bf558753096627b863835637a0f2f942b3b1", "start_char": 0, "end_char": 1316, "text_sha256": "aeb377e6bbda1a552066c5d1caf1bf558753096627b863835637a0f2f942b3b1"} [coumarin-p7668294] A genetic polymorphism in coumarin 7-hydroxylation: sequence of the human CYP2A genes and identification of variant CYP2A6 alleles. (1995). https://pubmed.ncbi.nlm.nih.gov/7668294/
    Complete structured claim and evidence

  3. K476E reduced NADPH oxidation and ferric-enzyme reduction; excess reductase did not restore wild-type coumarin hydroxylation.

    Human CYP2A6 K476E experimental variant → Coumarin 7-hydroxylation source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_span
    {"source_cache": "artifacts/coumarin-research/16207711.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "a5f0bef9ac62d55ff5725e8c5cb4eca3e76ef715c758654e76c0c596c52ceab7", "start_char": 0, "end_char": 1740, "text_sha256": "a5f0bef9ac62d55ff5725e8c5cb4eca3e76ef715c758654e76c0c596c52ceab7"}
    experimental_model
    Random mutagenesis of recombinant human CYP2A6
    exposure
    Wild-type enzyme and selected activity-reducing mutants
    limitations
    Engineered protein dysfunction is not nutrient deficiency; no rescue by nutritional supplementation was tested.
    nutrient_topic
    Coumarin research collection; topical membership is not evidence of a direct dietary effect. · Coumarin
    organism
    Human engineered protein
    plain_language
    Adding more partner enzyme did not fully repair this variant.
    primary_references
    [coumarin-p16207711] Analysis of coumarin 7-hydroxylation activity of cytochrome P450 2A6 using random mutagenesis. (2005). https://pubmed.ncbi.nlm.nih.gov/16207711/ DOI: 10.1074/jbc.m508171200
    tissue_or_cell_type
    Reconstituted enzyme system
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Coumarin: metabolism, signaling and nutrient connections (2026-09-17) · lines 618–629

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Random mutagenesis of recombinant human CYP2A6 · source_derived_draft · unverified_draft

    ### coumarin-k476e-hydroxylation K476E reduced NADPH oxidation and ferric-enzyme reduction; excess reductase did not restore wild-type coumarin hydroxylation. Condition category: machinery_impairment nutrient_topic: Coumarin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Adding more partner enzyme did not fully repair this variant. organism: Human engineered protein tissue_or_cell_type: Reconstituted enzyme system experimental_model: Random mutagenesis of recombinant human CYP2A6 limitations: Engineered protein dysfunction is not nutrient deficiency; no rescue by nutritional supplementation was tested. exposure: Wild-type enzyme and selected activity-reducing mutants evidence_span: {"source_cache": "artifacts/coumarin-research/16207711.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "a5f0bef9ac62d55ff5725e8c5cb4eca3e76ef715c758654e76c0c596c52ceab7", "start_char": 0, "end_char": 1740, "text_sha256": "a5f0bef9ac62d55ff5725e8c5cb4eca3e76ef715c758654e76c0c596c52ceab7"} [coumarin-p16207711] Analysis of coumarin 7-hydroxylation activity of cytochrome P450 2A6 using random mutagenesis. (2005). https://pubmed.ncbi.nlm.nih.gov/16207711/ DOI: 10.1074/jbc.m508171200
    Complete structured claim and evidence

  4. Nicotine inhibited CYP2A6 coumarin hydroxylation within the study inhibitor category of Ki below 200 micromolar.

    Nicotine → Coumarin 7-hydroxylation source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/coumarin-research/9143352.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dca3f4253c2977d47070bb95696634ee2e06fa9a28a3d76ac9790ce695ed6f09", "start_char": 0, "end_char": 2723, "text_sha256": "dca3f4253c2977d47070bb95696634ee2e06fa9a28a3d76ac9790ce695ed6f09"}
    experimental_model
    Human microsomal and recombinant CYP2A6 inhibitor screen
    exposure
    Coumarin 0.5–50 micromolar; 47 inhibitor/substrate probes
    limitations
    In vitro inhibition thresholds are not demonstrated clinical interactions at food exposure.
    nutrient_topic
    Coumarin research collection; topical membership is not evidence of a direct dietary effect. · Coumarin
    organism
    Human
    plain_language
    Nicotine and coumarin can interact in an enzyme assay.
    primary_references
    [coumarin-p9143352] Inhibition of coumarin 7-hydroxylase activity in human liver microsomes. (1997). https://pubmed.ncbi.nlm.nih.gov/9143352/ DOI: 10.1006/abbi.1997.9964
    tissue_or_cell_type
    Liver enzyme preparations

    Coumarin: metabolism, signaling and nutrient connections (2026-09-17) · lines 579–590

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human microsomal and recombinant CYP2A6 inhibitor screen · source_derived_draft · unverified_draft

    ### coumarin-nicotine-inhibition Nicotine inhibited CYP2A6 coumarin hydroxylation within the study inhibitor category of Ki below 200 micromolar. Condition category: normal nutrient_topic: Coumarin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Nicotine and coumarin can interact in an enzyme assay. organism: Human tissue_or_cell_type: Liver enzyme preparations experimental_model: Human microsomal and recombinant CYP2A6 inhibitor screen limitations: In vitro inhibition thresholds are not demonstrated clinical interactions at food exposure. exposure: Coumarin 0.5–50 micromolar; 47 inhibitor/substrate probes evidence_span: {"source_cache": "artifacts/coumarin-research/9143352.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dca3f4253c2977d47070bb95696634ee2e06fa9a28a3d76ac9790ce695ed6f09", "start_char": 0, "end_char": 2723, "text_sha256": "dca3f4253c2977d47070bb95696634ee2e06fa9a28a3d76ac9790ce695ed6f09"} [coumarin-p9143352] Inhibition of coumarin 7-hydroxylase activity in human liver microsomes. (1997). https://pubmed.ncbi.nlm.nih.gov/9143352/ DOI: 10.1006/abbi.1997.9964
    Complete structured claim and evidence

  5. Tranylcypromine competitively inhibited coumarin 7-hydroxylation, with Ki 0.04 micromolar.

    Tranylcypromine → Coumarin 7-hydroxylation source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/coumarin-research/9143352.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dca3f4253c2977d47070bb95696634ee2e06fa9a28a3d76ac9790ce695ed6f09", "start_char": 0, "end_char": 2723, "text_sha256": "dca3f4253c2977d47070bb95696634ee2e06fa9a28a3d76ac9790ce695ed6f09"}
    experimental_model
    Human microsomal and recombinant CYP2A6 inhibitor screen
    exposure
    Coumarin 0.5–50 micromolar; 47 inhibitor/substrate probes
    limitations
    In vitro inhibition thresholds are not demonstrated clinical interactions at food exposure.
    nutrient_topic
    Coumarin research collection; topical membership is not evidence of a direct dietary effect. · Coumarin
    organism
    Human
    plain_language
    A medicine inhibited the coumarin-processing reaction in vitro.
    primary_references
    [coumarin-p9143352] Inhibition of coumarin 7-hydroxylase activity in human liver microsomes. (1997). https://pubmed.ncbi.nlm.nih.gov/9143352/ DOI: 10.1006/abbi.1997.9964
    tissue_or_cell_type
    Liver enzyme preparations

    Coumarin: metabolism, signaling and nutrient connections (2026-09-17) · lines 566–577

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human microsomal and recombinant CYP2A6 inhibitor screen · source_derived_draft · unverified_draft

    ### coumarin-tranylcypromine-inhibition Tranylcypromine competitively inhibited coumarin 7-hydroxylation, with Ki 0.04 micromolar. Condition category: normal nutrient_topic: Coumarin research collection; topical membership is not evidence of a direct dietary effect. plain_language: A medicine inhibited the coumarin-processing reaction in vitro. organism: Human tissue_or_cell_type: Liver enzyme preparations experimental_model: Human microsomal and recombinant CYP2A6 inhibitor screen limitations: In vitro inhibition thresholds are not demonstrated clinical interactions at food exposure. exposure: Coumarin 0.5–50 micromolar; 47 inhibitor/substrate probes evidence_span: {"source_cache": "artifacts/coumarin-research/9143352.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dca3f4253c2977d47070bb95696634ee2e06fa9a28a3d76ac9790ce695ed6f09", "start_char": 0, "end_char": 2723, "text_sha256": "dca3f4253c2977d47070bb95696634ee2e06fa9a28a3d76ac9790ce695ed6f09"} [coumarin-p9143352] Inhibition of coumarin 7-hydroxylase activity in human liver microsomes. (1997). https://pubmed.ncbi.nlm.nih.gov/9143352/ DOI: 10.1006/abbi.1997.9964
    Complete structured claim and evidence

  6. Warfarin showed little or no CYP2A6 inhibition in this assay, with Ki above 200 micromolar.

    Warfarin → Coumarin 7-hydroxylation source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/coumarin-research/9143352.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dca3f4253c2977d47070bb95696634ee2e06fa9a28a3d76ac9790ce695ed6f09", "start_char": 0, "end_char": 2723, "text_sha256": "dca3f4253c2977d47070bb95696634ee2e06fa9a28a3d76ac9790ce695ed6f09"}
    experimental_model
    Human microsomal and recombinant CYP2A6 inhibitor screen
    exposure
    Coumarin 0.5–50 micromolar; 47 inhibitor/substrate probes
    limitations
    In vitro inhibition thresholds are not demonstrated clinical interactions at food exposure.
    nutrient_topic
    Coumarin research collection; topical membership is not evidence of a direct dietary effect. · Coumarin
    organism
    Human
    plain_language
    Warfarin is a separate molecule with a different principal target.
    primary_references
    [coumarin-p9143352] Inhibition of coumarin 7-hydroxylase activity in human liver microsomes. (1997). https://pubmed.ncbi.nlm.nih.gov/9143352/ DOI: 10.1006/abbi.1997.9964
    tissue_or_cell_type
    Liver enzyme preparations

    Coumarin: metabolism, signaling and nutrient connections (2026-09-17) · lines 592–603

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human microsomal and recombinant CYP2A6 inhibitor screen · source_derived_draft · unverified_draft

    ### coumarin-warfarin-inhibition-null Warfarin showed little or no CYP2A6 inhibition in this assay, with Ki above 200 micromolar. Condition category: normal nutrient_topic: Coumarin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Warfarin is a separate molecule with a different principal target. organism: Human tissue_or_cell_type: Liver enzyme preparations experimental_model: Human microsomal and recombinant CYP2A6 inhibitor screen limitations: In vitro inhibition thresholds are not demonstrated clinical interactions at food exposure. exposure: Coumarin 0.5–50 micromolar; 47 inhibitor/substrate probes evidence_span: {"source_cache": "artifacts/coumarin-research/9143352.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dca3f4253c2977d47070bb95696634ee2e06fa9a28a3d76ac9790ce695ed6f09", "start_char": 0, "end_char": 2723, "text_sha256": "dca3f4253c2977d47070bb95696634ee2e06fa9a28a3d76ac9790ce695ed6f09"} [coumarin-p9143352] Inhibition of coumarin 7-hydroxylase activity in human liver microsomes. (1997). https://pubmed.ncbi.nlm.nih.gov/9143352/ DOI: 10.1006/abbi.1997.9964
    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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