Polypharmacological profile of 1,2-dihydro-2-oxo-pyridine-3-carboxamides in the endocannabinoid system

Abstract The endocannabinoid system (ECS) represents one of the major neuromodulatory systems involved in different physiological and pathological processes. Multi-target compounds exert their activities by acting via multiple mechanisms of action and represent a promising pharmacological modulation of the ECS. In this work we report 4-substituted and 4,5-disubstituted 1,2-dihydro-2-oxo-pyridine-3-carboxamide derivatives with a broad spectrum of affinity and functional activity towards both cannabinoid receptors and additional effects on the main components of the ECS. In particular compound B3 showed high affinity for CB1R ( K i  = 23.1 nM, partial agonist) and CB2R ( K i  = 6.9 nM, inverse agonist) and also significant inhibitory activity (IC 50  = 70 nM) on FAAH with moderate inhibition of ABHD12 (IC 50  = 2.5 μΜ). Compounds B4 , B5 and B6 that act as full agonists at CB1R and as partial agonists ( B5 and B6 ) or antagonist ( B4 ) at CB2R, exhibited an additional multi-target property by inhibiting anandamide uptake with sub-micromolar IC 50 values (0.28–0.62 μΜ). The best derivatives showed cytotoxic activity on U937 lymphoblastoid cells. Finally, molecular docking analysis carried out on the three-dimensional structures of CB1R and CB2R and of FAAH allowed to rationalize the structure-activity relationships of this series of compounds.