Quercetin is a very effective iron chelator. Supplemental quercetin is bioavailable increasing blood levels dose-dependently. Quercetin also crosses the blood-brain barrier. Quercetin is being investigated for use in the treatment of Parkinson’s disease.
If iron chelators work in Parkinson’s there should be some positive effect with supplemental quercetin. I very much doubt there will be. See the page on Parkinson’s disease. If quercetin does not work in the treatment of Parkinson’s disease then the narrative that treatment of Parkinson’s disease requires iron chelation has to be re-thought. I would avoid supplementing with quercetin until there are definite clinical studies to the effect that quercetin in the real world ameliorates symptoms of Parkinson’s disease which I think will be never.
Quercetin is found in fruits and vegetables. Querectin found in foods could have benefcial effects. Like other antioxidants, when obtained from food, quercetin could have beneficial effects.