title: Ultrapure ajulemic acid has improved CB2 selectivity with reduced CB1 activity.
abstract: Ajulemic acid, a side-chain analog of Δ(8)-THC-11-oic acid, was designed as a potent therapeutic agent free of the psychotropic adverse effects typical of most cannabinoids. Subsequent studies of ajulemic acid have yielded widely divergent findings on the occurrence of these adverse effects. To help resolve these discrepancies, we have prepared highly purified ajulemic acid using a different synthetic method than previously reported in the literature and compared its cannabinoid receptor binding constants with those obtained using several other preparations from different sources. Whereas CB2 binding did not vary greatly among all of the samples, the CB1 binding showed a wide range of affinities. The highly purified product (JBT-101) reported here had the weakest affinity for CB1 while the original preparation (HU-239) showed the strongest affinity for CB1. The CB1/CB2 ratio of affinities was 12.3 for JBT-101 whereas that for HU-239 was 0.19, a 65-fold difference. Functional responses such as catalepsy and hypothermia using JBT-101 versus HU-239 displayed reduced CB1 activity in keeping with the receptor binding data. Thus, earlier conclusions on the limited therapeutic index for ajulemic acid need to be reconsidered in the light of the data now obtained using JBT-101.
authors.affiliation: JB Therapeutics Inc. (now named Corbus Pharmaceuticals, Inc.), One Kendall Square, Bldg 200, Cambridge, MA 02139, United States.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Tepper
authors.affiliation: JB Therapeutics Inc. (now named Corbus Pharmaceuticals, Inc.), One Kendall Square, Bldg 200, Cambridge, MA 02139, United States.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Zurier
authors.affiliation: Department of Biochemistry & Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation St., Worcester, MA 01605, United States. Electronic address: sumner.burstein@umassmed.edu.
authors.forename: Sumner H
authors.initials: SH
authors.lastname: Burstein
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001665:Binding Sites / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D013759:Dronabinol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D005260:Female; D018922:HL-60 Cells; D006801:Humans; D051379:Mice; D008968:Molecular Conformation; D010147:Pain Measurement / Q000187:drug effects; D043884:Receptor, Cannabinoid, CB1 / Q000819:agonists* / Q000378:metabolism; D043885:Receptor, Cannabinoid, CB2 / Q000819:agonists* / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D043884:Receptor, Cannabinoid, CB1; D043885:Receptor, Cannabinoid, CB2; D013759:Dronabinol; C471849:lenabasum
keywords: Ajulemic acid; Cannabinoid receptors; Synthesis