Background:

Tolcapone is a novel, reversible and orally-bioavailable small-molecule catechol-O-methyltransferase (COMT) inhibitor used for as an adjunct to levodopa therapy for the treatment of Parkinson’s disease (PD). The chemical structure of tolcapone contains a catechol structure with two electron withdrawing substituents of a tendency to easily deliver a proton resulting in an anion that is highly affinitive for COMT (the value of 50% inhibition concentration IC₅₀of 36 nM in rat liver) and displaces other catechols (such as catecholamines and levodopa) from the COMT catalytic center to prevent methylation. Study results have that the use of tolcapone reduces the dosage but enhances the therapeutic effects of levodopa to control PD symptoms.

Reference

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