Neurodegenerative Shielding by Curcumin and Its Derivatives on Brain Lesions Induced by 6-OHDA Model of Parkinson's Disease in Albino Wistar Rats

Study was undertaken to evaluate the neurodegenerative defending potential of curcumin (CUR), demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC) on 6-hydroxydopamine-(6-OHDA) induced Parkinsonism model in rats. Curcuminoids were administered (60 mg/kg, body weight, per oral) for three weeks followed by unilateral injection of 6-OHDA on 22nd day (10 μg/2 μL) into the right striatum leading to extensive loss of dopaminergic cells. The behavioral observations, biochemical markers, quantification of dopamine (DA), DOPAC, and HVA followed by dopamine (D(2)) receptor binding assay and tyrosine hydroxylase (TH, using immunohistochemistry) were evaluated using HPLC after three weeks of lesion. Pretreated animals showed significant protection against neuronal degeneration compared to lesion animals by normalizing the deranged levels of biomarkers and showed the potency in the order CUR > DMC > BDMC. The same order of effectiveness was observed in D(2) receptors binding assay and TH immunohistochemistry study. We conclude that curcuminoids appear to shield progressive neuronal degeneration from increased oxidative attack in 6-OHDA-lesioned rats through its free radical scavenging mechanism, and DA, DOPAC, and HVA enhancing capabilities in the sequence of efficacy CUR > DMC > BDMC. Further, curcuminoids may have potential utility in treatment of many more oxidative stress-induced neurodegenerative disorders.