3-O-methyl-L-DOPA is a metabolite of L-DOPA , produced by the activity of catechol O-methyltransferase. 3-O-methyl-L-DOPA may have effects of its own or it may compete with the actions of L-DOPA.
Nebicapone is a reversible catechol-O-methyltransferase (COMT) inhibitor and is mainly metabolized by glucuronidation. Nebicapone is mainly peripherally acting inhibitor that decreases the biotransformation of L-DOPA to 3-O-methyl-DOPA by inhibition of CO