Moreover, curcumin was found to protect dopaminergic neurons from 6-OHDA-induced toxicity via restoration of striatal dopamine, dopamine metabolite, dihydroxyphenylacetic acid, and homovanillic acid in a 6-OHDA model of PD [36] In these studies, the neuroprotective action of curcumin may be mediated by a reduction of oxidative stress due to its iron-chelating property [37] or via the Wnt/β-catenin signaling pathway [38] or modulating bFGF/NGF/TrkA/Hsp70 expressions in the SN [39]. Here, NGF is linked to Parkinson disease.