Protective effect of nobiletin against apoptosis induced by 6-hydroxydoamine in human neuroblastoma cells

Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by the damage of dopaminergic neurons of substantia nigra. Despite considerable research, therapeutic approaches aimed at the prevention and long-term treatment of PD have not been quite successful. Therefore, there is a tendency for the identification of novel medical intervention derived from natural substances. Nobiletin, an important citrus flavonoid commonly present in sweet and bitter orange peel, has been suggested to act as a neuroprotective agent in animal models of PD. This study was aimed to assess the potentials of nobiletin in preventing neuronal death and caspase-3 in SH-SY5Y cells.

SH-SY5Y cells were grown in DMEM/F12 media supplemented with 10% fetal bovine serum. The 6-hydroxydopamine (6-OHDA) with or without nobiletin was added to cells. After 24h, the cells were examined for morphological changes under a light microscope and viability by MTT assay. The protective doses of nobiletin was chosen through a pilot study and accordingly the doses 50 and 250μM were selected for further assessments. Western blot assays were done to examine the effect of 6-OHDA with/without nobiletin on cleaved (active) caspase-3.

Our results showed that nobiletin is effective in attenuating the effect of 6-OHDA on cell viability by the MTT assay. Nobiletin also reduced the cleavage of caspase-3 induced by 6-OHDA.

These results suggest that nobiletin has protective effects against dopaminergic neural toxicity and its anti-apoptotic effect is involved, at least in part, in such protection.