Minor phytocannabinoid

Δ9-THCBTetrahydrocannabutol

Butyl homologue of THC isolated in 2020, with CB1 affinity comparable to that of THC.

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.

Receptors and activity

CB1Partial agonist88 out of 100
Ki 15 nM (CB1 humain) ; agoniste partiel au test de la tétrade chez la souris
CB2Modulator70 out of 100
Ki 51 nM (CB2 humain) ; efficacité fonctionnelle non caractérisée

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

Subjective signature

Calm: 15 out of 100; Relaxation of body and mind; reduced mental noise without marked drowsiness.
Clarity: 8 out of 100; Sustained attention and clear thinking; functional lucidity, not euphoria.
High: 18 out of 100; Euphoria and sensory intensity; altered perception of time and space.
Appetite: 15 out of 100; Stimulation of hunger and of taste appreciation (the “munchies” effect).
Sleep: 12 out of 100; Sedative effect: aids sleep onset and the continuity of deep sleep.

Editorial estimate, not clinical.

Pharmacology

Δ9-tetrahydrocannabutol (Δ9-THCB) is the butyl side-chain homologue of Δ9-THC, isolated in 2020 by Linciano, Citti and Cannazza's team from the medical cannabis variety FM2, together with cannabidibutol. Its structure was established by nuclear magnetic resonance, ultraviolet and infrared spectroscopy, circular dichroism and high-resolution mass spectrometry, then confirmed by stereoselective synthesis. Its affinity for the human CB1 (Ki of 15 nM) and CB2 (Ki of 51 nM) receptors is comparable to that of THC, and the tetrad test in mice shows partial agonist activity at CB1. No human data exist. In France the molecule is caught by the generic clause of Annex IV of the order of 22 February 1990 and by that of the ANSM decision of 22 May 2024.

Key sources.

History

Source: Cannabis sativa L.: isolated from the inflorescences of the Italian medical variety FM2, where it occurs only in trace amounts.

Biosynthetic pathway

Biosynthetic pathway: Δ9-THCB belongs to the butyl series of cannabinoids, a minor one in the plant, in which the olivetolic acid type precursor carries a four-carbon chain instead of five. Prenylation followed by enzymatic cyclisation leads to the corresponding acid, whose decarboxylation releases Δ9-THCB. This pathway is inferred by analogy with that of THC and has not been demonstrated enzyme by enzyme for the butyl series.

Legal framework

European Union: No control measure at European Union level names Δ9-THCB. Effective control remains a national competence and the status varies from one Member State to another, several countries having adopted, like France, generic definitions covering THC homologues.
France: Prohibited in France by a generic clause, without being named. Annex IV of the order of 22 February 1990 classifies as narcotics the tetrahydrocannabinols, their esters, ethers and salts, as well as the salts of those derivatives. The ANSM decision of 22 May 2024 added any substance derived from the benzo[c]chromene nucleus substituted notably at position 1 by a hydroxyl group, at position 3 by an alkyl chain, at position 6 by one or two alkyl groups and at position 9 by an alkyl group: Δ9-THCB matches that description. Its status is therefore that of a narcotic caught by a generic clause.