D-DOPA

 D -DOPA ( D -3,4-dihydroxyphenylalanine; dextrodopa) is similar to L -DOPA (levodopa), but with opposite chirality. Levo- and dextro- rotation reference a molecule's ability to rotate planes of polarized light in either direction. Whereas L -DOPA is moderately effective in the treatment of Parkinson's disease (PD) and Dopamine-responsive dystonia (DRD), D -DOPA is biologically inactive.