Synthesis and evaluation of paracetamol esters as novel fatty acid amide hydrolase inhibitors

ONNIS, VALENTINA;CONGIU, CENZO;BJÖRKLUND E;HEMPEL F;SÖDERSTRÖM E;FOWLER CJ

2010-01-01

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Abstract

Fatty acid amide hydrolase (FAAH) is the key hydrolytic enzyme for the endogenous cannabinoid receptor ligand anandamide. The synthesis and evaluation for their FAAH inhibitory activities of a series of 18 paracetamol esters are described. Structure−activity relationship studies indicated that the ester (33) with a 2-(4-(2-(trifluoromethyl)pyridin-4-ylamino)phenyl)acetic acid substituent was the most potent analogue in this series. The compound inhibited FAAH activity in a competitive manner with a Ki value of 0.16 μM. The compound was also able to inhibit the FAAH activity in rat basophilic leukemia cells as assessed by measuring either the hydrolysis of anandamide, the FAAH-dependent cellular accumulation of anandamide, or the FAAH-dependent recycling of tritium to the cell membranes. The compound also inhibited the activity of monoacylglycerol lipase (MGL), the enzyme responsible for the hydrolysis of the endogenous cannabinoid receptor ligand 2-arachidonoylglycerol, with an IC50 value of 1.9 μM. It is concluded that the compound may be a useful template for the design of potent novel inhibitors of FAAH.