['Pharmacological activation of cannabinoid CB(1) and CB(2) receptors is a therapeutic strategy to treat chronic and inflammatory pain. It was recently reported that a mixture of natural triterpenes α- and β-amyrin bound selectively to CB(1) receptors with a subnanomolar K(i) value (133 pM). Orally administered α/β-amyrin inhibited inflammatory and persistent neuropathic pain in mice through both CB(1) and CB(2) receptors. Here, we investigated effects of amyrins on the major components of the endocannabinoid system.', 'We measured CB receptor binding interactions of α- and β-amyrin in validated binding assays using hCB(1) and hCB(2) transfected CHO-K1 cells. Effects on endocannabinoid transport in U937 cells and breakdown using homogenates of BV2 cells and pig brain, as well as purified enzymes, were also studied.', 'There was no binding of either α- or β-amyrin to hCB receptors in our assays (K(i) > 10 µM). The triterpene β-amyrin potently inhibited 2-arachidonoyl glycerol (2-AG) hydrolysis in pig brain homogenates, but not that of anandamide. Although β-amyrin only weakly inhibited purified human monoacylglycerol lipase (MAGL), it also inhibited α,β-hydrolases and more potently inhibited 2-AG breakdown than α-amyrin and the MAGL inhibitor pristimerin in BV2 cell and pig brain homogenates.'] Does the antinociceptive triterpene β-amyrin inhibit 2-arachidonoylglycerol ( 2-AG ) hydrolysis without directly targeting cannabinoid receptors?