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.