norfloxacin

CHEBI:100246 ·resolve ·ANTIBACTERIAL ·EXACT SEEDED

A quinolinemonocarboxylic acid with broad-spectrum antibacterial activity against most gram-negative and gram-positive bacteria. Norfloxacin is bactericidal and its mode of action depends on blocking of bacterial DNA replication by binding itself to an enzyme called DNA gyrase. — ChEBI

Classification

fluoroquinolone antibioticARO:0000001

Strictly broader compounds or drug classes this molecule belongs to.

• Label unavailable CHEBI:23765
• Label unavailable CHEBI:26512
• Label unavailable CHEBI:46848
• quinolone antibiotic CHEBI:86324
• fluoroquinolone antibiotic CHEBI:87211
• fluoroquinolone antibiotic ARO:0000001

Chemical structure

SMILES

CCn1cc(C(=O)O)c(=O)c2cc(F)c(N3CCNCC3)cc21

InChI

InChI=1S/C16H18FN3O3/c1-2-19-9-11(16(22)23)15(21)10-7-12(17)14(8-13(10)19)20-5-3-18-4-6-20/h7-9,18H,2-6H2,1H3,(H,22,23)

Also called

• norfloxacine (INN)— chebi
• norfloxacino (INN)— chebi
• norfloxacinum (INN)— chebi
• 1-ethyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid (EXACT_SYNONYM)— chebi
• 1,4-Dihydro-1-ethyl-6-fluoro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid (EXACT_SYNONYM)— chebi
• 1-Ethyl-6-fluor-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-chinolincarbonsäure (EXACT_SYNONYM)— chebi
• 1-Ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid (EXACT_SYNONYM)— chebi
• NFLX (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.

• norfloxacinARO:3000662
• cas:70458-96-7
• gmelin:1576626
• hmdb:HMDB0015192
• kegg.compound:C06687
• lincs.smallmolecule:LSM-5286
• reaxys:567897
• vsdb:1831
• chembl:CHEMBL9
• pubchem.compound:4539

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.

• drugbank:DB01059
• drugcentral:1967
• kegg.drug:D00210

Patents and articles

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

• patent:BE863429
• patent:DE2840910
• patent:US4146719
• patent:US4292317
• wikipedia.en:Norfloxacin

Activity roles

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

• antimicrobial agent CHEBI:33281
• antibacterial drug CHEBI:36047

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.

Molecular targets

The molecular entity or process this compound acts on. Each target carries evidence — this is a mechanistic claim, not a classification.

fluoroquinolone sensitive gyrA PROTEIN DIRECT_BINDING_TARGET

ARO:3000733

CARD/ARO database assertion; target organism, strain, and assay are not specified. ARO explicitly describes ligand binding to gyrase subunit A. Evidence status: PRIMARY_EVIDENCE_NEEDED. Source: CARD_ARO 2026-08-30 (retrieved 2026-08-30).

• ARO:3000733 (CARD/ARO asserts targeted_by_antibiotic ARO:3000662 (norfloxacin); database assertion, not a primary citation.)

Fluoroquinolone sensitive parC PROTEIN DIRECT_BINDING_TARGET

ARO:3000735

CARD/ARO database assertion; target organism, strain, and assay are not specified. ParC is asserted as the fluoroquinolone-sensitive subunit. Evidence status: PRIMARY_EVIDENCE_NEEDED. Source: CARD_ARO 2026-08-30 (retrieved 2026-08-30).

• ARO:3000735 (CARD/ARO asserts targeted_by_antibiotic ARO:3000662 (norfloxacin); database assertion, not a primary citation.)

Mechanism summary

Mode of action

NUCLEIC_ACID_SYNTHESIS_INHIBITION microbial target — CURATOR: Confirmed as bacterial DNA gyrase inhibition after primary norfloxacin mechanism review. PMID:2536729; PMID:2982149; PMID:3010848.

Clinical status

APPROVED

Resistance mechanisms

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

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.

Norfloxacin inhibits bacterial DNA gyrase supercoiling MECHANISTIC

Norfloxacin binds the DNA-DNA gyrase reaction complex and inhibits DNA gyrase-catalyzed supercoiling, disrupting bacterial chromosome topology control.

Curation history

1. SEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources

   Seeded from data/raw/ inventories (ARO, CHEBI)

2. RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

3. RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

4. RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

5. RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

6. RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

7. CURATED_CAUSAL_GRAPH 2026-09-04 · codex · LLM-assisted

   Added a PMID-supported causal graph for norfloxacin inhibition of bacterial DNA gyrase supercoiling and marked the coarse target scope as curator-reviewed.

8. RESEEDED_FROM_SOURCES 2026-09-10 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

9. RESEEDED_FROM_SOURCES 2026-10-16 · seed_from_sources

   Re-seeded; changed: resistance_mechanisms (CARD). Upstream retrieval date 2026-08-30, unchanged.

10. CURATED_UNIPROT_PROTEIN_EXAMPLES 2026-10-18 · antigravity · LLM-assisted

    Added curated E. coli K-12 reference-strain DNA gyrase subunit A (P0AES4) and subunit B (P0AES6) UniProtKB protein examples on the norfloxacin_dna_gyrase_supercoiling_inhibition dna_gyrase causal graph node.

Provenance

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

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