triclosan
CHEBI:164200
·resolve ·ANTIBACTERIAL
·EXACT
SEEDED
An aromatic ether that is phenol which is substituted at C-5 by a chloro group and at C-2 by a 2,4-dichlorophenoxy group. It is widely used as a preservative and antimicrobial agent in personal care products such as soaps, skin creams, toothpaste and deodorants as well as in household items such as plastic chopping boards, sports equipment and shoes. — ChEBI
Machine-generated and unreviewed. Identity, structure and
cross-references come straight from ChEBI's and CARD's own data; no curator has
signed off on this record yet.
Classification
disinfecting agents and antisepticsARO:3005386
Strictly broader compounds or drug classes this molecule belongs to.
Chemical structure
Computed structure properties
| Molecular formula | C12H7Cl3O2 |
|---|
| Charge | 0 |
|---|
| Average mass | 289.545 Da |
|---|
| Monoisotopic mass | 287.95116 Da |
|---|
| Source | ChEBI |
|---|
| InChIKey | XEFQLINVKFYRCS-UHFFFAOYSA-N |
|---|
SMILES
Oc1cc(Cl)ccc1Oc1ccc(Cl)cc1Cl
InChI
InChI=1S/C12H7Cl3O2/c13-7-1-3-11(9(15)5-7)17-12-4-2-8(14)6-10(12)16/h1-6,16H
Also called
- triclosanum (INN)— chebi
- triclosán (INN)— chebi
- 5-chloro-2-(2,4-dichlorophenoxy)phenol (EXACT_SYNONYM)— chebi
- 2,4,4'-Trichloro-2'-hydroxydiphenyl ether (EXACT_SYNONYM)— chebi
- 5-Chloro-2-(2,4-dichloro-phenoxy)-phenol (EXACT_SYNONYM)— chebi
- Triclosan (EXACT_SYNONYM)— chebi
Cross-references
Equivalent identifiers for this same structure in other resources.
Activity roles
Every antimicrobial role a source asserts for this compound — the
unreduced evidence behind its antimicrobial_class.
Source concepts
Every upstream concept that resolved to this record. The merge is
the product: this is what shows ChEBI and CARD are describing the same structure.
Upstream concepts merged into this record
| Source | Native ID | Label | Minted CURIE | Version |
|---|
| ARO |
ARO:3000870 |
triclosan |
antibioticmech:aro-f5e0894a20 |
2026-08-30 |
| CHEBI |
CHEBI:164200 |
triclosan |
antibioticmech:chebi-4fb85f3941 |
2026-08-30 |
Molecular targets
The molecular entity or process this compound acts on. Each target
carries evidence — this is a mechanistic claim, not a classification.
antibiotic sensitive enoyl-acyl carrier reductase PROTEIN DIRECT_BINDING_TARGET
ARO:3000872
CARD/ARO database assertion; target organism, strain, and assay are not specified. Enoyl-ACP reductase is asserted as the blocked enzyme. Evidence status: PRIMARY_EVIDENCE_NEEDED. Source: CARD_ARO 2026-08-30 (retrieved 2026-08-30).
- ARO:3000872 (CARD/ARO asserts targeted_by_antibiotic ARO:3000870 (triclosan); database assertion, not a primary citation.)
Replicase polyprotein 1ab VIRAL_PROTEIN MEASURED_TARGET_ASSOCIATION
BindingDB quantitative measurement in the named target organism; source assay descriptions and identifiers are retained per measurement. Evidence status: PRIMARY_EVIDENCE. Source: BINDINGDB 2026-09 (retrieved 2026-08-31).
Severe acute respiratory syndrome coronavirus NCBITaxon:2901879
Quantitative measurements
| Type | Reported value | Assay | BindingDB IDs | Reference |
|---|
| IC50 |
75000 nM |
Various Assay
This is a review article. Please point to the original journal. |
RSID 1074309
assay 10079_1
monomer 8726 |
PMID:34798775 |
Organism-specific examples
| Protein | Gene | Organism | Entry |
|---|
Replicase polyprotein 1ab UniProtKB:P0C6X7 |
— |
Severe acute respiratory syndrome coronavirus |
REVIEWED |
- PMID:34798775 (BindingDB literature-curated quantitative target measurement; source value, assay text, reaction-set ID, and target organism retained.)
Trans-2-enoyl-ACP reductase II PROTEIN MEASURED_TARGET_ASSOCIATION
BindingDB quantitative measurement in the named target organism; source assay descriptions and identifiers are retained per measurement. Evidence status: PRIMARY_EVIDENCE. Source: BINDINGDB 2026-09 (retrieved 2026-08-31).
Streptococcus pneumoniae NCBITaxon:1313
Quantitative measurements
| Type | Reported value | Assay | BindingDB IDs | Reference |
|---|
| IC50 |
>30000 nM |
Enzyme Inhibition Assay
Assays were carried out in half-area, 96-well microtiter plates. Compounds were evaluated in assay mixtures containing components specific for each enzyme. Inhibitors were varied over the range 0.01-10 uM. The consumption of NAD(P)H was monitored for 20 min at 30 °C by following the change in absorbance at 340 nm. IC50 values were estimated from a fit of the initial velocities to a standard equation. Triclosan was included in all assays as a positive control. |
RSID 14752
assay 1080_1
monomer 8726 |
PMID:12699381 |
Organism-specific examples
| Protein | Gene | Organism | Entry |
|---|
Probable nitronate monooxygenase UniProtKB:Q9FBC5 |
— |
Streptococcus pneumoniae |
UNREVIEWED |
- PMID:12699381 (BindingDB literature-curated quantitative target measurement; source value, assay text, reaction-set ID, and target organism retained.)
Mechanism summary
- Mode of action
- CELL_MEMBRANE_SYNTHESIS_INHIBITION microbial target — CURATOR: Reassigned after review of FabI/enoyl-ACP reductase inhibition in bacterial fatty-acid synthesis; primary reports identify FabI rather than dihydrofolate reductase as the antibacterial target for triclosan. PMID:10196195; PMID:10201369; PMID:9707111.
Resistance mechanisms
10 known routes by which microbes
resist this compound, grounded in ARO where CARD models them. Grouped by mechanism
type — expand a group to see its determinants.
ANTIBIOTIC_EFFLUX 6
ANTIBIOTIC_EFFLUX
| Determinant | ARO ID | Organism | Gene families | Evidence |
|---|
| AcrAB-TolC |
ARO:3000384 |
not organism-specific |
— |
- ARO:3000384 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000870 (triclosan); database assertion, not a primary citation.)
|
| Klebsiella pneumoniae KpnEF |
ARO:3004585 |
not organism-specific |
— |
- ARO:3004585 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000870 (triclosan); database assertion, not a primary citation.)
|
| MexJK |
ARO:3009148 |
not organism-specific |
— |
- ARO:3009148 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000870 (triclosan); database assertion, not a primary citation.)
|
| MexJK-OpmH |
ARO:3003691 |
not organism-specific |
— |
- ARO:3003691 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000870 (triclosan); database assertion, not a primary citation.)
|
| TriABC-OpmH |
ARO:3003678 |
not organism-specific |
— |
- ARO:3003678 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000870 (triclosan); database assertion, not a primary citation.)
|
| abeM |
ARO:3000753 |
not organism-specific |
— |
- ARO:3000753 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000870 (triclosan); database assertion, not a primary citation.)
|
ANTIBIOTIC_TARGET_ALTERATION 4
ANTIBIOTIC_TARGET_ALTERATION
| Determinant | ARO ID | Organism | Gene families | Evidence |
|---|
| Escherichia coli fabG mutations conferring resistance to triclosan |
ARO:3004049 |
not organism-specific |
— |
- ARO:3004049 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000870 (triclosan); database assertion, not a primary citation.)
|
| Escherichia coli fabI mutations conferring resistance to isoniazid and triclosan |
ARO:3004045 |
not organism-specific |
— |
- ARO:3004045 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000870 (triclosan); database assertion, not a primary citation.)
|
| Escherichia coli gyrA with mutation conferring resistance to triclosan |
ARO:3004335 |
not organism-specific |
— |
- ARO:3004335 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000870 (triclosan); database assertion, not a primary citation.)
|
| Salmonella enterica gyrA with mutation conferring resistance to triclosan |
ARO:3004334 |
not organism-specific |
— |
- ARO:3004334 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000870 (triclosan); database assertion, not a primary citation.)
|
Causal graphs
Evidence-backed mechanism graphs: how the compound reaches its
target, what the target does, and how the effect propagates to growth inhibition
or death.
Triclosan inhibits bacterial FabI fatty-acid synthesis MECHANISTIC
Triclosan forms a tight inhibited FabI-NAD-triclosan state, blocking bacterial enoyl-acyl carrier protein reductase activity in type II fatty-acid synthesis and limiting membrane lipid biosynthesis.
Nodes — triclosan_fabi_fatty_acid_synthesis_inhibition
| Node | Label | Type | Grounding |
|---|
triclosan |
triclosan |
COMPOUND |
CHEBI:164200 |
fabi |
bacterial FabI enoyl-ACP reductase |
GENE_OR_PROTEIN |
ARO:3000872 |
fabi_nad_triclosan_state |
inhibited FabI-NAD-triclosan state |
STATE |
REVIEWED_LABEL_ONLY |
enoyl_acp_reductase_activity |
enoyl-acyl carrier protein reductase activity |
MOLECULAR_FUNCTION |
REVIEWED_LABEL_ONLY |
type_ii_fatty_acid_biosynthesis |
type II fatty-acid biosynthesis |
PATHWAY |
REVIEWED_LABEL_ONLY |
membrane_lipid_biosynthesis |
membrane lipid biosynthesis |
BIOLOGICAL_PROCESS |
REVIEWED_LABEL_ONLY |
Edges — triclosan_fabi_fatty_acid_synthesis_inhibition
| Subject | Predicate | Object | Evidence |
|---|
triclosan |
stabilizes |
fabi_nad_triclosan_state |
- PMID:10196195 (Heath and colleagues found that triclosan inhibits bacterial fatty-acid synthesis at FabI and increases FabI affinity for NAD+.)
|
fabi |
participates in |
fabi_nad_triclosan_state |
- PMID:10201369 (Levy and colleagues connected triclosan activity to FabI in bacterial cells.)
|
fabi_nad_triclosan_state |
inhibits |
enoyl_acp_reductase_activity |
- PMID:10196195 (Mechanistic FabI assays linked triclosan binding to inhibition of the enoyl-ACP reductase step.)
|
fabi |
enables |
enoyl_acp_reductase_activity |
- PMID:9707111 (McMurry and colleagues identified lipid synthesis as the triclosan target pathway and FabI as the sensitive enzyme.)
|
enoyl_acp_reductase_activity |
supports |
type_ii_fatty_acid_biosynthesis |
- PMID:10196195 (The FabI inhibition study placed the triclosan-sensitive step in the bacterial fatty-acid synthesis cycle.)
|
type_ii_fatty_acid_biosynthesis |
supports |
membrane_lipid_biosynthesis |
- PMID:9707111 (Lipid synthesis experiments connected triclosan-sensitive FabI activity to the broader lipid biosynthesis pathway.)
|
Curation history
-
SEEDED_FROM_SOURCES
2026-08-30 · seed_from_sources
Seeded from data/raw/ inventories (ARO, CHEBI)
-
RESEEDED_FROM_SOURCES
2026-08-30 · seed_from_sources
Re-seeded from updated data/raw/ inventories
-
RESEEDED_FROM_SOURCES
2026-08-30 · seed_from_sources
Re-seeded from updated data/raw/ inventories
-
RESEEDED_FROM_SOURCES
2026-08-31 · seed_from_sources
Re-seeded from updated data/raw/ inventories
-
RESEEDED_FROM_SOURCES
2026-08-31 · seed_from_sources
Re-seeded from updated data/raw/ inventories
-
RESEEDED_FROM_SOURCES
2026-08-31 · seed_from_sources
Re-seeded from updated data/raw/ inventories
-
RESEEDED_FROM_SOURCES
2026-08-31 · seed_from_sources
Re-seeded from updated data/raw/ inventories
-
CURATED_CAUSAL_GRAPH
2026-09-04 · codex · LLM-assisted
Added a PMID-supported causal graph for triclosan inhibition of bacterial FabI fatty-acid synthesis and marked the coarse mode of action as curator-reviewed.
Provenance
Seeded by scripts/seed_from_sources.py from the committed
inventories in data/raw/.
View the record.