Semi-synthetic cannabinoid

HU-331Cannabidiol hydroxyquinone

Quinone of cannabidiol, a catalytic inhibitor of topoisomerase II studied in preclinical research.

Harm-reduction warning

No characterised human dose: animal / in vitro data only. Effect profile, safety margin and acute toxicity are not documented in human clinical practice. Extremely potent compound: severe effects, seizures and deaths reported in the literature.

2D structure

C₂₁H₂₈O₃

Names

Common name: Cannabidiol hydroxyquinone
IUPAC name: 3-hydroxy-2-[(1R,6R)-3-methyl-6-prop-1-en-2-ylcyclohex-2-en-1-yl]-5-pentylcyclohexa-2,5-diene-1,4-dione
Other names: HU-331 · CBDHQ · CBD-quinone · Quinone du cannabidiol

Identifiers

Formula: C₂₁H₂₈O₃
Molar mass: 328.40 g/mol
CAS: 137252-25-6
PubChem CID: 11393311(new tab)
ChEBI: CHEBI:197014(new tab)
InChIKey: WDXXEUARVHTWQF-DLBZAZTESA-N

Class

Family: Semi-synthetic cannabinoid

Legal status

Status: Unscheduled

Updated on 11 October 2026

Contents

Receptors and activity

Topoisomérase IIαAntagonist80 out of 100
inhibiteur catalytique : bloque la relaxation de l'ADN à des concentrations micromolaires sans cassures, inhibition non compétitive de l'ATPase (Regal et coll., 2014)
Angiogenèse (cellules endothéliales)Antagonist60 out of 100
inhibition significative dès 300 nM sur anneau aortique de rat (Kogan et coll., 2006)

Bar length shows the relative strength of the interaction, as an indication.

Subjective signature

Calm: 2 out of 100; Relaxation of body and mind; reduced mental noise without marked drowsiness.
Clarity: 2 out of 100; Sustained attention and clear thinking; functional lucidity, not euphoria.
High: 0 out of 100; Euphoria and sensory intensity; altered perception of time and space.
Appetite: 2 out of 100; Stimulation of hunger and of taste appreciation (the “munchies” effect).
Sleep: 2 out of 100; Sedative effect: aids sleep onset and the continuity of deep sleep.

Editorial estimate, not clinical.

Pharmacology

HU-331, or cannabidiol hydroxyquinone, is the para-quinone obtained by oxidation of cannabidiol, described in 2004 by Kogan, Mechoulam and colleagues together with the quinones of Δ8-THC and cannabinol. All three compounds showed antiproliferative activity on human cancer cell lines in vitro. Later work identified its mechanism: a highly specific inhibition of topoisomerase II, with no cell cycle arrest, no apoptosis of tumour cells and no production of reactive oxygen species. A 2014 study specifies that it is a catalytic inhibitor of topoisomerase IIα, which does not cause DNA strand breaks. In mice bearing tumour grafts, a 2007 comparison describes it as less cardiotoxic than doxorubicin; in HT-29 colon carcinoma, tumour weight in the treated group was 54 % lower than in the control group. No human trial has been conducted.

Key sources.

History

Source: An oxidation product of cannabidiol: the resorcinol core of CBD is converted into a hydroxy-para-quinone. It was prepared and studied at the Hebrew University of Jerusalem, hence the prefix HU.

Route of preparation (chemical process)

Route of preparation: HU-331 derives from cannabidiol by oxidation of the resorcinol core into a quinone. This is a chemical transformation of the oxidation class, not an enzymatic pathway of the plant.

Legal framework

European Union: No control measure of its own at European Union level. The molecule appears in no schedule of the 1961 Convention on Narcotic Drugs or of the 1971 Convention on Psychotropic Substances. It holds no marketing authorisation and no novel food authorisation under Regulation (EU) 2015/2283: it circulates only as a chemical or reference standard intended for research.
France: Unscheduled substance. HU-331 is named in no annex of the order of 22 February 1990 and falls under no generic clause: it is not a tetrahydrocannabinol and it lacks the benzo[c]chromene nucleus targeted by the ANSM decision of 22 May 2024. This absence of scheduling is not an authorisation: the molecule is neither an authorised medicine nor an ingredient permitted in food or cosmetics, and its use belongs exclusively to research.

Sources: EUR-Lex, UNODC, CND, ANSM, IUPHAR/BPS, ChEBI, EUDA. Our method.

References

Structured data

SMILES: CCCCCC1=CC(=O)C(=C(C1=O)O)[C@@H]2C=C(CC[C@H]2C(=C)C)C
InChIKey: WDXXEUARVHTWQF-DLBZAZTESA-N

Machine-readable entry (JSON)

LLM ingestion format: a structured superset of the entry (identifiers, binding, versioned legal status). Full corpus.