Table 1.
Cannabinoid Receptor Activities of Major Phytocannabinoids
| Compound | CB1 | CB2 | ||||
|---|---|---|---|---|---|---|
| Mode of action | Efficacy (%) | EC50 (μM) | Mode of action | Efficacy (%) | EC50 (μM) | |
| CP-55940 | Agonist | 100 | 0.0025±0.0009 | Agonist | 100 | 0.0026±0.0004 |
| AM-630 | — | — | — | Antagonist | 100 | 0.146±0.084 |
| SR-141716 | Antagonist | 129 | 0.024±0.003 | — | — | — |
| Δ9-THC | Partial agonist | 60 | 0.015±0.001 | Weak partial agonist | 20 | >10 |
| Δ9-THCA | Weak agonist | 100 | 1.8±0.7 | Weak agonist | 100 | 30±15 |
| CBD | Antagonist | 40 | >10 | Antagonist | 100 | 7±2 |
| CBDA | NA | 0 | >10 | NA | −23 | >10 |
CP-55940 was used as a reference agonist in CB1 receptor assays, SR-141716 as a reference antagonist in CB1, and AM-630 was used as a reference antagonist in CB2 receptor assays.
Δ9-THC, Δ9-tetrahydrocannabinol; Δ9-THCA, Δ9-tetrahydrocannabinolic acid; CB, cannabinoid; CBD, cannabidiol; CBDA, cannabidiolic acid; NA, no activity.