o-orsellinic acid

CHEBI:32807 EXACT SEEDED

What these status tags mean

Curation status describes a workflow state. SEEDED means the record entered through the source-seeding workflow; it does not imply that no later curation occurred. PROPOSED marks an addition awaiting review; REVIEWED records curator sign-off on identity, structure, filing class and producer claims; DEPRECATED retains a superseded or out-of-scope record. These are workflow decisions, not independently verified human review. Agent-assisted contributions may appear in the record history.

Grounding describes the identifier mapping: EXACT uses an ontology identity asserted by the source; MINTED keeps a local identifier when no defensible ontology identity is available; REVIEW_NEEDED flags an exact structure whose ontology identity needs adjudication. The grounding note retains any unresolved alternatives. These tags do not establish the strength of producer or activity evidence.

A dihydroxybenzoic acid that is 2,4-dihydroxybenzoic acid in which the hydrogen at position 6 is replaced by a methyl group.

Structure

Standard InChIKey	AMKYESDOVDKZKV-UHFFFAOYSA-N
SMILES	CC1=CC(=CC(=C1C(=O)O)O)O
Stereochemistry	fully defined
Cross-references	pubchem:68072, npatlas:NPA024876, chembl:CHEMBL457583

Filing pathway

Shikimates and phenylpropanoids — computed by NPClassifier npclassifier.gnps2.org@2026-09-07, which is why it is pinned rather than recomputed. The gene cluster's asserted class is pks, terpene, from MIBiG.

Producer organisms 5

A claim that this taxon makes the compound. The basis says what the evidence addressed — a knockout and a database assertion are not the same claim.

Taxon	Basis	Cluster	Evidence
Aspergillus nidulans FGSC A4 NCBITaxon:227321	BGC_CHARACTERIZED	mibig:BGC0000057	PMID:20174687
Fusarium graminearum PH-1 NCBITaxon:229533	BGC_CHARACTERIZED	mibig:BGC0002594	PMID:25011010
Colletotrichum higginsianum IMI 349063 NCBITaxon:759273	BGC_CORRELATED	mibig:BGC0002812	DOI:10.1016/j.ymben.2023.10.002
Moniliophthora roreri MCA 2997 NCBITaxon:1381753	SOURCE_ASSERTION	mibig:BGC0002212	DOI:10.1126/sciadv.aar5459
Claviceps purpurea 20.1 NCBITaxon:1111077	SOURCE_ASSERTION	mibig:BGC0002596	PMID:33130255

Occurrences 22

Somebody found the compound in this organism and cited it. That is not a claim that the organism makes it, and nothing here promotes one to the other.

Taxon	Source	Reference
Nidularia pulvinata NCBITaxon:1081941	LOTUS	DOI:10.1515/ZNC-1997-5-606
Hypoxylon rubiginosum NCBITaxon:110542	LOTUS	DOI:10.1021/NP040063L
Penicillium purpurogenum NCBITaxon:1266744	CHEBI	PMID:21879714
Ascomycota sp. Ind19F07 NCBITaxon:1583058	CHEBI	PMID:25537370
Aspergillus nidulans NCBITaxon:162425	LOTUS	DOI:10.1073/PNAS.0901870106
Parmotrema stuppeum NCBITaxon:2041279	LOTUS	DOI:10.1515/ZNC-2000-11-1227
Parmotrema tinctorum NCBITaxon:235862	LOTUS	DOI:10.4268/CJCMM20141620
Dolichousnea longissima NCBITaxon:281306	LOTUS	DOI:10.1016/S0031-9422(00)82466-8
Parmotrema cooperi NCBITaxon:2910500	LOTUS	DOI:10.1007/S11426-011-4436-2
Aspergillus terreus NCBITaxon:33178	LOTUS	DOI:10.1016/J.PHYTOL.2015.02.009
Aspergillus terreus NCBITaxon:33178	LOTUS	DOI:10.1039/C39720000391
Penicillium aurantiogriseum NCBITaxon:36655	LOTUS	DOI:10.1039/C39920000646
Chaetomium globosum NCBITaxon:38033	LOTUS	DOI:10.1021/NP058014B
Umbilicaria torrefacta NCBITaxon:392743	LOTUS	DOI:10.1016/0031-9422(90)83052-3
Aspergillus flavus NCBITaxon:5059	LOTUS	DOI:10.1271/BBB.63.820
Penicillium NCBITaxon:5073	LOTUS	DOI:10.1021/NP500885F
Escherichia coli NCBITaxon:562	LOTUS	DOI:10.1073/PNAS.0901870106
Penicillium cyclopium NCBITaxon:60167	LOTUS	DOI:10.1039/C39920000646
Aspergillus fumigatus NCBITaxon:746128	LOTUS	DOI:10.1042/BJ0970321
Aspergillus fumigatus NCBITaxon:746128	LOTUS	DOI:10.1042/BJ0980353
Aspergillus fumigatus NCBITaxon:746128	LOTUS	DOI:10.1080/13693780802307720
Stachybotrys cylindrospora NCBITaxon:80386	LOTUS	DOI:10.1139/V93-069

Biosynthetic gene clusters 5

Accession	Host	Locus evidence	Genome
mibig:BGC0000057	Aspergillus nidulans FGSC A4 NCBITaxon:227321	CLUSTER_DEMONSTRATED	genbank:AACD01000135.1
mibig:BGC0002594	Fusarium graminearum PH-1 NCBITaxon:229533	CLUSTER_DEMONSTRATED	genbank:CM000575.1
mibig:BGC0002812	Colletotrichum higginsianum IMI 349063 NCBITaxon:759273	CLUSTER_CORRELATED	genbank:LTAN01000004.1
mibig:BGC0002212	Moniliophthora roreri MCA 2997 NCBITaxon:1381753	CLUSTER_UNSTATED	genbank:AWSO01000045.1
mibig:BGC0002596	Claviceps purpurea 20.1 NCBITaxon:1111077	CLUSTER_UNSTATED	genbank:CAGA01000059.1

A locus claim and a taxon claim are different questions. Heterologous expression settles the first and leaves the second where the isolation report left it.

Biosynthesis curated

Written by a curator with claim-level evidence on each step; not derived from a source. This is what the rest of the record exists to support.

Step	Enzyme	Reaction	Substrate → product	Evidence
1	OrsA UniProtKB:Q5AUX1	RHEA:62973	ungrounded → CHEBI:16162	DOI:10.1039/b904541d

Step 1: This curates the Aspergillus nidulans FGSC A4 non-reducing polyketide synthase OrsA from the BGC0000057/AACD01000135.1 route; OrsA condenses acetyl-CoA with three malonyl-CoA units to form o-orsellinate, the physiological conjugate base of the record compound o-orsellinic acid.

Mechanism & Biosynthesis Overview

Causal graph — biosynthesis 4 nodes, 3 edges

Partial Aspergillus nidulans o-orsellinic acid biosynthesis graph for OrsA condensation of acetyl-CoA and malonyl-CoA units to o-orsellinate.

Subject	Predicate	Object	Notes	Evidence
acetyl-CoA(4-)	is condensed by	OrsA	RHEA:62973 selects acetyl-CoA as the starter unit in the OrsA o-orsellinate synthase reaction.	DOI:10.1039/b904541d DOI:10.1073/pnas.0901870106 https://www.uniprot.org/uniprotkb/Q5AUX1 https://www.ncbi.nlm.nih.gov/protein/EAA59563.1 reference DOI:10.1039/b904541d evidence type PRIMARY_EXPERIMENT snippet the polyketide synthase alone is required for orsellinic acid biosynthesis notes Sanchez et al. used targeted deletions in Aspergillus nidulans and found that OrsA, the polyketide synthase encoded in the Ors/F9775 cluster, is sufficient for o-orsellinic acid biosynthesis. reference DOI:10.1073/pnas.0901870106 evidence type PRIMARY_EXPERIMENT snippet one induced gene cluster codes for the long-sought after polyketide synthase notes Schroeckh et al. identified the bacterium-induced Aspergillus nidulans orsellinic acid/F9775 cluster and genetically connected its polyketide synthase to production of orsellinic acid and related products. reference https://www.uniprot.org/uniprotkb/Q5AUX1 evidence type DATABASE_ASSERTION retrieved on 2026-09-27 notes Reviewed UniProtKB:Q5AUX1 is the Aspergillus nidulans FGSC A4 OrsA orsellinic acid synthase, length 2103 aa, annotates the left-to-right physiological RHEA:62973 reaction, and cross-references EMBL AACD01000135 protein EAA59563.1. reference https://www.ncbi.nlm.nih.gov/protein/EAA59563.1 evidence type DATABASE_ASSERTION retrieved on 2026-09-27 notes NCBI GenPept EAA59563.1 is locus_tag AN7909.2 from the BGC0000057 AACD01000135.1 Aspergillus nidulans FGSC A4 locus and is sequence-identical to reviewed UniProtKB:Q5AUX1.
malonyl-CoA(5-)	is condensed by	OrsA	RHEA:62973 consumes three malonyl-CoA units per o-orsellinate formed by OrsA.	DOI:10.1039/b904541d DOI:10.1073/pnas.0901870106 https://www.uniprot.org/uniprotkb/Q5AUX1 https://www.ncbi.nlm.nih.gov/protein/EAA59563.1 reference DOI:10.1039/b904541d evidence type PRIMARY_EXPERIMENT snippet the polyketide synthase alone is required for orsellinic acid biosynthesis notes Sanchez et al. used targeted deletions in Aspergillus nidulans and found that OrsA, the polyketide synthase encoded in the Ors/F9775 cluster, is sufficient for o-orsellinic acid biosynthesis. reference DOI:10.1073/pnas.0901870106 evidence type PRIMARY_EXPERIMENT snippet one induced gene cluster codes for the long-sought after polyketide synthase notes Schroeckh et al. identified the bacterium-induced Aspergillus nidulans orsellinic acid/F9775 cluster and genetically connected its polyketide synthase to production of orsellinic acid and related products. reference https://www.uniprot.org/uniprotkb/Q5AUX1 evidence type DATABASE_ASSERTION retrieved on 2026-09-27 notes Reviewed UniProtKB:Q5AUX1 is the Aspergillus nidulans FGSC A4 OrsA orsellinic acid synthase, length 2103 aa, annotates the left-to-right physiological RHEA:62973 reaction, and cross-references EMBL AACD01000135 protein EAA59563.1. reference https://www.ncbi.nlm.nih.gov/protein/EAA59563.1 evidence type DATABASE_ASSERTION retrieved on 2026-09-27 notes NCBI GenPept EAA59563.1 is locus_tag AN7909.2 from the BGC0000057 AACD01000135.1 Aspergillus nidulans FGSC A4 locus and is sequence-identical to reviewed UniProtKB:Q5AUX1.
OrsA	forms	o-orsellinate	The curated Rhea reaction forms o-orsellinate, which is the physiological conjugate base of o-orsellinic acid.	DOI:10.1039/b904541d DOI:10.1073/pnas.0901870106 https://www.uniprot.org/uniprotkb/Q5AUX1 https://www.ncbi.nlm.nih.gov/protein/EAA59563.1 reference DOI:10.1039/b904541d evidence type PRIMARY_EXPERIMENT snippet the polyketide synthase alone is required for orsellinic acid biosynthesis notes Sanchez et al. used targeted deletions in Aspergillus nidulans and found that OrsA, the polyketide synthase encoded in the Ors/F9775 cluster, is sufficient for o-orsellinic acid biosynthesis. reference DOI:10.1073/pnas.0901870106 evidence type PRIMARY_EXPERIMENT snippet one induced gene cluster codes for the long-sought after polyketide synthase notes Schroeckh et al. identified the bacterium-induced Aspergillus nidulans orsellinic acid/F9775 cluster and genetically connected its polyketide synthase to production of orsellinic acid and related products. reference https://www.uniprot.org/uniprotkb/Q5AUX1 evidence type DATABASE_ASSERTION retrieved on 2026-09-27 notes Reviewed UniProtKB:Q5AUX1 is the Aspergillus nidulans FGSC A4 OrsA orsellinic acid synthase, length 2103 aa, annotates the left-to-right physiological RHEA:62973 reaction, and cross-references EMBL AACD01000135 protein EAA59563.1. reference https://www.ncbi.nlm.nih.gov/protein/EAA59563.1 evidence type DATABASE_ASSERTION retrieved on 2026-09-27 notes NCBI GenPept EAA59563.1 is locus_tag AN7909.2 from the BGC0000057 AACD01000135.1 Aspergillus nidulans FGSC A4 locus and is sequence-identical to reviewed UniProtKB:Q5AUX1.

Every edge carries its own citation; an uncited edge is refused by the corpus tests.

Causal graph — biosynthesis 4 nodes, 3 edges

MITE-reported farnesyl-prenylation of exact o-orsellinic acid as substrate. AscA is the sequence-verified native Acremonium egyptiacum F-1392 reference. This separate database context consumes the owner compound and does not replace its Aspergillus nidulans OrsA synthesis pathway or transfer producer or BGC assertions. Functional evidence remains database-level; the primary paper was inaccessible. Product geometry and ionic-form limits remain explicit; existing open discussions and SEEDED status are preserved.

Subject	Predicate	Object	Notes	Evidence
AscA native F-1392 reference	is_database_reported_catalyst_of	MITE-reported AscA farnesyl-prenylation	MITE and reviewed UniProt supply database functional attribution; native sequence equality establishes reference correspondence, not historical assay-stock or construct identity. The primary paper was inaccessible. UniProt's Mg2+ annotation is by similarity, not a native cofactor measurement; no occupancy, kinetics, localization or physical complex is adopted.	https://github.com/mite-standard/mite_data/blob/6eacd913b2036376031072f69cbb33908f132998/mite_data/data/MITE0000374.json https://www.uniprot.org/uniprotkb/A0A455R413 https://www.ncbi.nlm.nih.gov/protein/BBF25313.1 https://www.ncbi.nlm.nih.gov/nuccore/LC406756.1 reference https://github.com/mite-standard/mite_data/blob/6eacd913b2036376031072f69cbb33908f132998/mite_data/data/MITE0000374.json evidence type DATABASE_ASSERTION retrieved on 2026-10-07 notes Active MITE0000374 version1 names AscA/A0A455R413/BBF25313.1 and BGC0001923. Its single reaction example consumes orsellinic acid and marks ilicicolinic acid B intermediate. Heterologous expression is the database evidence code, not an independently inspected primary experiment. Its DOI is truncated 10.1073/pnas.181925411; GenPept and UniProt identify the full citation as 10.1073/pnas.1819254116. That primary paper was inaccessible. snippet Prenylates orsellinic acid in the ascochlorin/ascofuranone biosynthetic pathway. reference https://www.uniprot.org/uniprotkb/A0A455R413 evidence type DATABASE_ASSERTION retrieved on 2026-10-07 notes Current Swiss-Prot entry20/sequence1,336aa, ascA/taxon749675, with F-1392 in genomic-sequence reference provenance and EMBL LC406756/BBF25313.1 link. Its reaction uses orsellinate and (2E,6E)-farnesyl diphosphate to form ilicicolinate B, RHEA63012/left-to-right63013. Database assertion, not a newly inspected assay. Mg2+ is ECO0000250 by similarity to P32378; broad downstream narrative and predicted membrane features are not adopted. reference https://www.ncbi.nlm.nih.gov/protein/BBF25313.1 evidence type DATABASE_ASSERTION retrieved on 2026-10-07 notes Independent complete336-aa native prenyltransferase, UbiA family, geneascA, Acremonium egyptiacum F-1392/taxon749675. Its reverse coded_by is LC406756.1:2461..3471. Native reference only, not an assay construct. reference https://www.ncbi.nlm.nih.gov/nuccore/LC406756.1 evidence type CURATOR_INFERENCE retrieved on 2026-10-07 notes Full1011-nt reverse-CDS2461..3471, codon1/defaulttable1, equals native annotation, independent GenPept and current UniProt, all336aa. Independent coded_by coordinates/DNA and F-1392/taxon749675 agree. Complete33001-bp cluster retained; metadata and full target CDS inspected, not a whole-genome annotation audit.
o-orsellinic acid	is_database_example_substrate_of	MITE-reported AscA farnesyl-prenylation	The pinned exact-structure screen matches the MITE neutral-acid example to full owner key AMKYESDOVDKZKV-UHFFFAOYSA-N with complete stereochemistry. UniProt's orsellinate reaction is a distinct ionic representation, not a replacement owner identity. No exact native assay substrate, synthesis by AscA or new production claim inferred.	https://github.com/mite-standard/mite_data/blob/6eacd913b2036376031072f69cbb33908f132998/mite_data/data/MITE0000374.json reference https://github.com/mite-standard/mite_data/blob/6eacd913b2036376031072f69cbb33908f132998/mite_data/data/MITE0000374.json evidence type DATABASE_ASSERTION retrieved on 2026-10-07 notes Active MITE0000374 version1 names AscA/A0A455R413/BBF25313.1 and BGC0001923. Its single reaction example consumes orsellinic acid and marks ilicicolinic acid B intermediate. Heterologous expression is the database evidence code, not an independently inspected primary experiment. Its DOI is truncated 10.1073/pnas.181925411; GenPept and UniProt identify the full citation as 10.1073/pnas.1819254116. That primary paper was inaccessible.
MITE-reported AscA farnesyl-prenylation	has_database_example_product	Ilicicolinic acid B, database intermediate	MITE's ilicicolinic acid B example is intermediate and leaves alkene geometry unspecified. It remains externally ungrounded; no ionic Rhea product identifier or stereospecific product mapping is transferred. No downstream enzyme sequence, product finality, BGC0001923 transfer or native reference-organism producer upgrade is inferred. Existing OrsA synthesis and all source fields remain.	https://github.com/mite-standard/mite_data/blob/6eacd913b2036376031072f69cbb33908f132998/mite_data/data/MITE0000374.json reference https://github.com/mite-standard/mite_data/blob/6eacd913b2036376031072f69cbb33908f132998/mite_data/data/MITE0000374.json evidence type DATABASE_ASSERTION retrieved on 2026-10-07 notes Active MITE0000374 version1 names AscA/A0A455R413/BBF25313.1 and BGC0001923. Its single reaction example consumes orsellinic acid and marks ilicicolinic acid B intermediate. Heterologous expression is the database evidence code, not an independently inspected primary experiment. Its DOI is truncated 10.1073/pnas.181925411; GenPept and UniProt identify the full citation as 10.1073/pnas.1819254116. That primary paper was inaccessible.

Every edge carries its own citation; an uncited edge is refused by the corpus tests.

Bioactivities 5

Entries preserve source qualifiers, targets and evidence. Repeated assay names or values are not independent replications; inspect source detail for differences.

Assay	Result	Target enzyme	Source detail
Validation qHTS for agonist of cAMP-regulated guanine nucleotide exchange factor 3 (EPAC1)	OTHER 89.1251 uM; NOT_DETERMINED	Not recorded	pubchem.aid:1645883 assay Validation qHTS for agonist of cAMP-regulated guanine nucleotide exchange factor 3 (EPAC1) evidence reference pubchem.aid:1645883 evidence type DATABASE_ASSERTION notes PubChem BioAssay AID 1645883, deposited by NCGC; assay type Confirmatory. Source outcome: Inconclusive. Source endpoint: Potency. call NOT_DETERMINED measurement type OTHER value 89.1251 units uM
Validation qHTS for agonist of cAMP-regulated guanine nucleotide exchange factor 3 (EPAC1)	OTHER 89.1251 uM; NOT_DETERMINED	UniProtKB:O95398	pubchem.aid:1645883 assay Validation qHTS for agonist of cAMP-regulated guanine nucleotide exchange factor 3 (EPAC1) evidence reference pubchem.aid:1645883 evidence type DATABASE_ASSERTION notes PubChem BioAssay AID 1645883, deposited by NCGC; assay type Confirmatory. Source outcome: Inconclusive. Source endpoint: Potency. call NOT_DETERMINED measurement type OTHER value 89.1251 units uM target enzyme UniProtKB:O95398
qHTS Assay for Activators of Cytochrome P450 3A4	OTHER 25.1189 uM; INACTIVE	Not recorded	pubchem.aid:885 assay qHTS Assay for Activators of Cytochrome P450 3A4 evidence reference pubchem.aid:885 evidence type DATABASE_ASSERTION notes PubChem BioAssay AID 885, deposited by NCGC; assay type Confirmatory. Source endpoint: Potency. Target accession NP_059488 was left ungrounded because PubChem did not provide a UniProtKB accession. call INACTIVE measurement type OTHER value 25.1189 units uM
qHTS Assay for Inhibitors and Substrates of Cytochrome P450 3A4	OTHER 25.1189 uM; ACTIVE	Not recorded	pubchem.aid:884 assay qHTS Assay for Inhibitors and Substrates of Cytochrome P450 3A4 evidence reference pubchem.aid:884 evidence type DATABASE_ASSERTION notes PubChem BioAssay AID 884, deposited by NCGC; assay type Confirmatory. Source endpoint: Potency. Target accession NP_059488 was left ungrounded because PubChem did not provide a UniProtKB accession. call ACTIVE measurement type OTHER value 25.1189 units uM
qHTS Assay for Inhibitors of the Human Apurinic/apyrimidinic Endonuclease 1 (APE1)	OTHER 0.0089 uM; INACTIVE	Not recorded	pubchem.aid:2517 assay qHTS Assay for Inhibitors of the Human Apurinic/apyrimidinic Endonuclease 1 (APE1) evidence reference pubchem.aid:2517 evidence type DATABASE_ASSERTION notes PubChem BioAssay AID 2517, deposited by NCGC; assay type Confirmatory. Source endpoint: Potency. Target accession 1DE9_A was left ungrounded because PubChem did not provide a UniProtKB accession. call INACTIVE measurement type OTHER value 0.0089 units uM

Explore across X-Mech

AntibioticMech (o-orsellinic acid) ↗ MediaIngredientMech (CHEBI:32807) ↗ TaxonMech: Aspergillus nidulans FGSC A4 (NCBITaxon:227321) ↗ TaxonMech: Fusarium graminearum PH-1 (NCBITaxon:229533) ↗ TaxonMech: Colletotrichum higginsianum IMI 349063 (NCBITaxon:759273) ↗ TaxonMech: Moniliophthora roreri MCA 2997 (NCBITaxon:1381753) ↗ PathwayMech (mibig:BGC0000057) ↗ PathwayMech (mibig:BGC0002594) ↗ PathwayMech (mibig:BGC0002812) ↗

Open questions 2

name-disagreement — ChEBI calls this structure 'o-orsellinic acid' and MIBiG calls it 'Orsellinic acid', 'orsellinic acid'. They share a Standard InChIKey, so if the names denote different compounds then one upstream record has the wrong structure. Check which.

shared-structure — This structure is reported by more than one MIBiG entry: BGC0000057, BGC0002212, BGC0002594, BGC0002596, BGC0002812. Confirm they describe the same compound rather than an upstream cross-reference error.

Provenance

Source concept	Source	Version
BGC0000057	MIBIG	5
BGC0002594	MIBIG	2
BGC0002812	MIBIG	2
BGC0002212	MIBIG	3
BGC0002596	MIBIG	2
CHEBI:32807	CHEBI	3-star

This page is generated from data/natural_products/shikimates_and_phenylpropanoids/o-orsellinic-acid.yaml, which is generated from the committed inventories. Neither is edited by hand.