“Conclusions/Significance These observations suggest that oral administration of EGCG may have significant beneficial effects in Parkinson's patients treated with L-DOPA and carbidopa by exerting a modest inhibition of L-DOPA methylation plus a strong neuroprotection against oxidative damage and degeneration.”
“EGCG strongly inhibited human liver COMT-mediated O-methylation of L-DOPA in a concentration-… in vitro, with an average IC 50 of 0.36 µM. Oral administration of EGCG moderately lowered the accumulation of 3-O-methyldopa in … plasma and striatum of rats treated with L-DOPA + carbidopa.”