cis-Entacapone is a metabolite of the catechol-O-methyltransferase (COMT) inhibitor entacapone. It is also a potential impurity found in commercial preparations of entacapone and a degradant of entacapone formed by UV light exposure.

Entacapone sodium salt inhibits catechol-O-methyltransferase(COMT) with similar IC50 in different tissues including live, duodenum, kidney and lung, but entacapone is more active than tolcapone in those tissues. Entacapone (< 100 μM) is a potent inhibitor of α-syn and β-amyloid (Aβ) oligomerization and fibrillogenesis, and also protects against extracellular toxicity induced by the aggregation of both proteins in PC12 cells.Entacapone sodium salt is a specific, potent, peripherally acting catechol-O-methyltransferase (COMT) inhibitor with IC50 of 151 nM for PD treatment.

Entacapone (OR-611) is a selective and reversible inhibitor of catechol-O-methyltransferase (COMT).