Curcuma longa extract ameliorates motor and cognitive deficits of 6-hydroxydopamine-infused Parkinson’s disease model rats

Parkinson’s disease (PD) results mostly from the degeneration of dopaminergic neurons in the substantia nigra pars compacta. It is characterized by the manifestations of anxiety, tremor, muscle rigidity, bradykinesia and cognitive impairments. Oxidative stress is attributed to the neurodegeneration of PD. Curcuma longa is a commonly used spice and has high levels of anti-oxidative phyto-constituents. Here, we evaluated whether the chronic oral administration of C. longa extract affects the degree of anxiety, neuromotor and cognitive deficits of 6-hydroxydopamine (6-OHDA)-infused PD model rats. Following the surgery, animals were orally administered with C. longa extract for twelve weeks. The degree of anxiety/depression, motor and cognitive performances were determined with a variety of neurobehavioral experimental paradigms, including elevated plus, Morris water maze task, rotarod, open field, forced swim, sucrose preference and tail suspension tests. Brain levels of lipid peroxide (LPO) were measured by standard method. Tumor necrosis factor-α (TNFα), α-synuclein, synaptosome-associated protein-25 (SNAP25) and brain-derived neurotrophic factor (BDNF) of the brain tissues were measured by ELISA. Oral administration of C. longa significantly ( P < 0.05) protected the deterioration of the motor activity, learning-related memory cognitions and the degree of anxiety- and depression-like behaviors in PD model rats. The preventive effects were accompanied with decreased brain levels of LPO, TNFα, α-synuclein and increased levels of cognition-related proteins SNAP-25 and BDNF. The experimental results suggest that C. longa ameliorates PD-like symptoms by suppressing the oxidative/pro-inflammatory stress and levels of α-synuclein and increasing the levels of SNAP-25 and BDNF.