Interaction of Phytochemical Components Determine the Protective Effect of Riceberry Rice Bran Extract against Oxidative-Induced Neuronal Cell Death in SK-N-SH Cells

Abstract

Aging leads to a progressive impairment of mitochondrial function and/or increased oxidative damage has been suggested to play critical roles in the pathogenesis of the neurodegenerative diseases. Brains have a high metabolic rate and relatively low capacity for cellular regeneration, nerve cells in brain area are particularly susceptible damaged by ROS. This study aimed to investigate the effects of Riceberry rice bran extract (RBBE) on H₂O₂-induced oxidative neuronal toxicity in SK-N-SH cells by measurement of cell viability, intracellular ROS, and mitochondria membrane potential (MPP). Co-treatment results indicated that RBBE and cyanidin acted as pro-oxidants at high level of oxidative stress induced by 400 µM H₂O₂. Therefore, the pre-treatment method was chosen for this study. High dose H₂O₂ 800 μM resulted in a statistically significant increase in ROS level, and cell death with a decreasing MMP trend. Pretreatment with RRBE at concentration of 5 mg/ml before exposure to H₂O₂ showed neuroprotective ability by increasing the percentage of cell viability and decreasing the ROS level to the level not different from control.  Moreover, the MMP was raised to the level higher than control. However, cyanidin in the dose that contained in 5 mg/ml RBBE did not improved the oxidative neuronal damage. These results might suggest that pre-treatment cells with RBBE attenuated the neuronal cell death resulted from the interaction of mixed phytocemical components in RBBE.