Polyphenols protect against the neuronal damage induced by oxidative stress [abstract]

Abstract

Oxidative stress is thought to be the cause of many neurodegenerative diseases, such as Parkinson's, Alzheimer's and stroke. In searching for preventative measures, many antioxidant botanical compounds are being researched in hope of finding a protective effect. Resveratrol is a polyphenolic antioxidant that is found in high concentrations in grape skin and red wine. Curcumin is another polyphenol antioxidant that is in the turmeric root, which is the main ingredient in curry powder. In this study, we investigate these two compounds on the anti-oxidative and neuroprotective effects using undifferentiated and differentiated human neuroblastoma cells SH-SY5Y. Oxidative stress is induced by menadione, a quinone compound known to generate reactive oxygen species (ROS) in the cells. SH-SY5Y cells were pretreated with 80µM resveratrol or 20µM curcumin for 25 minutes, followed by 10µM of menadione for 1 to 2 hours. Cell viability was evaluated with the MTT protocol, which is an indicator of mitochondrial respiratory chain activity. Cell morphology was assessed by examining under a Nikon inverted microscope. Cells were differentiated by addition of 10 μM retinoic acid for six days. The MTT results showed that cell survival decreased after oxidative insult induced by menadione and both curcumin and resveratrol could attenuate the damage induced by menadione. Morphological observation demonstrated that menadione treatment caused extension of cell processes in non-differentiated cells and disruption of the processes in differentiated SH-SY5Y. Curcumin administration provided significant protection against the cell damage induced by the menadione. Taken together, these studies demonstrated the ability of polyphenolic compounds such as curcumin and resveratrol to exert anti-oxidant effect and protect the neuron-like cells against oxidative insult.