triclosan

CHEBI:164200 ·resolve ·ANTIBACTERIAL ·EXACT REVIEWED

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

Classification

disinfecting agents and antisepticsARO:3005386

Strictly broader compounds or drug classes this molecule belongs to.

Label unavailable CHEBI:23697
Label unavailable CHEBI:33853
Label unavailable CHEBI:35618
Label unavailable CHEBI:83403
disinfecting agents and antiseptics ARO:3005386

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

Identifiers for this same structure in other resources. An accession that lands on two different structures in this corpus is withheld from both rather than shown here, since it names at most one of them.

Drug registries

Identifiers that name a drug rather than a structure. One of these can cover a parent compound, its salts and its stereoisomers, which this corpus keeps as separate records, so it is not an equivalence of structure.

Patents and articles

Documents about this compound. A patent covers a class and an article covers a topic; neither identifies a structure.

Activity roles

Every antimicrobial role a source asserts for this compound — the unreduced evidence behind its antimicrobial_class.

fungicide CHEBI:24127
antibacterial agent CHEBI:33282
antimalarial CHEBI:38068

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.)

enoyl-acyl carrier protein reductase (FabI) PROTEIN DIRECT_BINDING_TARGET

Wild-type and G93-variant enzyme assays measured triclosan inhibition; triclosan-NAD+ cocrystals were obtained for G93A, G93S, and G93V E. coli FabI, with G93V increasing IC50 from 150 to 68,500 nM. Evidence status: PRIMARY_EVIDENCE. Source: PRIMARY_LITERATURE 2010-11 (retrieved 2026-09-02).

Escherichia coli NCBITaxon:562

Organism-specific examples
Protein	Gene	Organism	Entry
Enoyl-[acyl-carrier-protein] reductase [NADH] FabI `UniProtKB:P0AEK4` Direct enoyl-ACP reductase enzyme target forming the ternary FabI-NAD+-triclosan complex in E. coli (PMID:21094257; K-12 reference strain context).	fabI	Escherichia coli (strain K12) `NCBITaxon:83333`	REVIEWED

PMID:21094257 (Primary triclosan-bound E. coli FabI-mutant structures and resistance measurements (DOI:10.1016/j.jsb.2010.11.008).)

Mechanism summary

Mode of action: CELL_MEMBRANE_SYNTHESIS_INHIBITION microbial target — CURATOR: PMID:21094257 measured 150 nM inhibition of wild-type Escherichia coli enoyl-acyl carrier protein reductase (FabI) and resolved triclosan-NAD+ complexes of G93A, G93S, and highly resistant G93V enzymes. These data support inhibition of bacterial type-II fatty-acid/envelope synthesis, replacing the seed's unsupported folate-pathway assignment; the structures are mutant, not wild-type, complexes.

Resistance mechanisms

10 source-backed resistance determinants or associations, with ARO grounding where reported. Grouped by reported mechanism type.

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 Examples: Enoyl-[acyl-carrier-protein] reductase [NADH] FabI (fabI) `UniProtKB:P0AEK4`, Escherichia coli (strain K12) `NCBITaxon:83333` REVIEWED — Type II fatty-acid synthesis enoyl-ACP reductase that forms the noncovalent FabI-NAD+-triclosan ternary complex in E. coli (PMID:9675027; PMID:10220315, PDB 1QSG; PMID:21094257; K-12 reference strain context).	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.)

Record-level evidence

PMID:21094257 (Primary exact-triclosan FabI structural, enzyme-inhibition, and G93V-resistance study.)

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
REVIEWED 2026-09-02 · codex · LLM-assisted
Verified exact ChEBI/CARD identity, structure, roles, antibacterial class, and provenance of retained CARD/BindingDB assertions; corrected the folate-pathway seed to fatty-acid/envelope synthesis inhibition and added the primary E. coli FabI target with mutant-structure boundaries.
RESEEDED_FROM_SOURCES 2026-09-02 · 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.
RESEEDED_FROM_SOURCES 2026-09-10 · seed_from_sources
Re-seeded from updated data/raw/ inventories
CURATED_UNIPROT_PROTEIN_EXAMPLES 2026-10-18 · antigravity · LLM-assisted
Added curated E. coli K-12 FabI (P0AEK4) UniProtKB protein examples on the triclosan_fabi_fatty_acid_synthesis_inhibition fabi causal graph node and the PRIMARY_LITERATURE FabI molecular target.

Provenance

Seeded by scripts/seed_from_sources.py from the committed inventories in data/raw/. View the record (YAML).

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