Additive Protective Effects of Luteolin and Pyruvate against 6-Hydroxydopamine and 3-Hydroxykynurenine Induced Neurotoxicity in SH-SY5Y Cells

Oxidative stress has been implicated as one of the causes in cell death in many neurodegenerative disorders. Due to antioxidative properties in vitro, the use of flavonoids and other polyphenolic compounds synthesised by plants are considered to be a promising strategy to prevent Alzheimer’s disease and Parkinsons’s disease. In the present study, we tested protective effects of some polyphenols and sodium pyruvate on 6-hydroxydopamine (6-OHDA), salsolinol and 3-hydroxykynurenine (3-HK) induced neurotoxicity in human neuroblastoma SH-SY5Y cells. We found that luteolin prevented from 6-OHDA and 3-HK induced cell viability reduction and that one of the mechanisms involved in the neuroprotective process was the ability to increase the level of cellular ATP. However, luteolin was ineffective against salsolinol-induced toxicity. Neither pre-treatment with flavonoids nor simultaneous addition had any protective effects on 6-OHDA, salsolinol or 3-HK induced neurotoxicity. Interestingly, both pre-treatment and co-treatment with pyruvate provided protection against 6-OHDA, salsolinol or 3-HK induced toxicity. Moreover, luteolin and sodium pyruvate, administered together, acted additively, so to achieve the same effect, lower concentrations were needed. The ability of luteolin and sodium pyruvate to reduce toxicity of 6-OHDA and 3-HK in SH-SY5Y cells may be related to two different neuroprotective mechanisms and the capability to penetrate into the cell.