Tetrahydromagnolol (Magnolignan), a main metabolite of Magnolol, is a potent and selective cannabinoid CB2 receptor agonist with an EC 50 of 170 nM and a K i of 416 nM. Tetrahydromagnolol possesses 20-fold more selective for CB2 receptor than CB1 receptor. Tetrahydromagnolol is also a weak GPR55 receptor antagonist Form:Solid IC50& Target:CB2 170 nM (EC 50 ) CB2 416 nM (Ki) CB1 9010 nM (EC 50 ) CB1 2260 nM (Ki) GPR55 receptor