Dose-dependent effect of Curcuma longa for the treatment of Parkinson's disease

Curcuma longa is a plant that belongs to the ginger family, Zingiberaceae. It has been used in Siddha medicine for thousands of years in Asia. Parkinson's disease (PD) is a degenerative disorder of the central nervous system that affects the motor system of the brain. Death of dopamine-producing cells in the substantia nigra leads to PD. Exposure to salsolinol, which is an endogenous neurotoxin, has been associated with damage to dopamine-producing cells. The present study assessed the toxicity of salsolinol in SH-SY5Y human neuroblastoma cells and subsequently investigated the neuroprotective potential of C. longa extract in salsolinol-induced toxic conditions in SH-SY5Y cells. Sulphorhodamine-B assay showed the protective effect of the anti-apoptotic effect of treated SH-SY5Y cells. Fluorescence microscopy and confocal laser scanning microscope analysis indicated the anti-apoptotic impact of the C. longa extract. Mitochondria-derived reactive oxygen species were reduced in C. longa extract-treated SH-SY5Y cells. Downregulated mRNA expression levels of p53, Bcl-2-associated X protein and caspase 3 were observed in the C. longa extract-treated SH-SY5Y cells. Caspase 3 activity was reduced in the C. longa extract-treated SH-SY5Y cells. In conclusion, the present findings demonstrated that solsolinol is neurotoxic to SH-SY5Y cells, and C. longa extract may be useful in the treatment of PD.