http://www.ncbi.nlm.nih.gov/pubmed/22622825

Curcumin protects nigral dopaminergic neurons by iron-chelation in the 6-hydroxydopamine rat model of Parkinson's disease.

Abstract
OBJECTIVE:

Curcumin is a plant polyphenolic compound and a major component of spice turmeric (Curcuma longa). It has been reported to possess free radical-scavenging, iron-chelating, and anti-inflammatory properties in different tissues. Our previous study showed that curcumin protects MES23.5 dopaminergic cells from 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in vitro. The present study aimed to explore this neuroprotective effect in the 6-OHDA-lesioned rat model of Parkinson's disease in vivo.
METHODS:

Rats were given intragastric curcumin for 24 days. 6-OHDA lesioning was conducted on day 4 of curcumin treatment. Dopamine content was assessed by high-performance liquid chromatography with electrochemical detection, tyrosine hydroxylase (TH)-containing neurons by immunohistochemistry, and iron-containing cells by Perls' iron staining.
RESULTS:

The dopamine content in the striatum and the number of TH-immunoreactive neurons decreased after 6-OHDA treatment. Curcumin pretreatment reversed these changes. Further studies demonstrated that 6-OHDA treatment increased the number of iron-staining cells, which was dramatically decreased by curcumin pretreatment.
CONCLUSION:

The protective effects of curcumin against 6-OHDA may be attributable to the iron-chelating activity of curcumin to suppress the iron-induced degeneration of nigral dopaminergic neurons.