Isolation of a High Affinity Cannabinoid for Human CB1 Receptor from a Medicinal Cannabis Variety: Δ9-Tetrahydrocannabutol, the Butyl Homologue of Δ9-Tetrahydrocannabinol
Pasquale Linciano, Cinzia Citti, Livio Luongo, Carmela Belardo, Sabatino Maione, Maria Angela Vandelli, Flavio Forni, Giuseppe Gigli, Aldo Laganà, Carmela Maria Montone, Giuseppe Cannazza
Journal of Natural Products, 2019 Dec 31.
The butyl homologues of Δ9-tetrahydrocannabinol, Δ9-tetrahydrocannabutol (Δ9-THCB), and cannabidiol, cannabidibutol (CBDB), were isolated from a medicinal Cannabis sativa variety (FM2) inflorescence. Appropriate spectroscopic and spectrometric characterization, including NMR, UV, IR, ECD, and HRMS, was carried out on both cannabinoids. The chemical structures and absolute configurations of the isolated cannabinoids were confirmed by comparison with the spectroscopic data of the respective compounds obtained by stereoselective synthesis. The butyl homologue of Δ9-THC, Δ9-THCB, showed an affinity for the human CB1 (Ki = 15 nM) and CB2 receptors (Ki = 51 nM) comparable to that of (-)-trans-Δ9-THC. Docking studies suggested the key bonds responsible for THC-like binding affinity for the CB1 receptor. The formalin test in vivo was performed on Δ9-THCB in order to reveal possible analgesic and anti-inflammatory properties. The tetrad test in mice showed a partial agonistic activity of Δ9-THCB toward the CB1 receptor.