Ultrapure ajulemic acid has improved CB2 selectivity with reduced CB1 activity.
Mark A Tepper, Robert B Zurier, Sumner H Burstein
Bioorganic & Medicinal Chemistry July 1, 2014 DOI: 10.1016/j.bmc.2014.04.062 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Preclinical laboratory study Peer reviewed |
|---|---|
| Measures | cannabinoid receptor binding constants (CB1, CB2), catalepsy, hypothermia |
| Keywords | Ajulemic acid Cannabinoid receptors Synthesis |
| Key points | Highly purified ajulemic acid (JBT-101), made by a different synthetic method, bound CB1 much more weakly than the original preparation (HU-239): CB1/CB2 affinity ratios were 12.3 versus 0.19, a 65-fold difference, while CB2 binding varied little. Catalepsy and hypothermia responses were reduced with JBT-101, matching the binding data. The authors argue earlier conclusions about ajulemic acid's limited therapeutic index should be reconsidered. |
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.