Neuroprotective effects of urolithin A on H₂O₂-induced oxidative stress-mediated apoptosis in SK-N-MC cells

Neuroprotective effects of Momordica charantia extract against hydrogen peroxide-induced cytotoxicity in human neuroblastoma SK-N-MC cells / 한국영양학회지

PURPOSE: Many studies have suggested that neuronal cells protect against oxidative stress-induced apoptotic cell death by polyphenolic compounds. We investigated the neuroprotective effects and the mechanism of action of Momordica charantia ethanol extract (MCE) against H₂O₂-induced cell death of human neuroblastoma SK-N-MC cells. METHODS: The antioxidant activity of MCE was measured by the quantity of total phenolic acid compounds (TPC), quantity of total flavonoid compounds (TFC), and 2,2-Diphenyl-1-pycrylhydrazyl (DPPH) radical scavenging activity. Cytotoxicity and cell viability were determined by CCK-8 assay. The formation of reactive oxygen species (ROS) was measured using 2,7-dichlorofluorescein diacetate (DCF-DA) assay. Antioxidant enzyme (SOD-1,2 and GPx-1) expression was determined by real-time PCR. Mitogen-activated protein kinases (MAPK) pathway and apoptosis signal expression was measured by Western blotting. RESULTS: The TPC and TFC quantities of MCE were 28.51 mg gallic acid equivalents/extract g and 3.95 mg catechin equivalents/extract g, respectively. The IC₅₀ value for DPPH radical scavenging activity was 506.95 µg/ml for MCE. Pre-treatment with MCE showed protective effects against H₂O₂-induced cell death and inhibited ROS generation by oxidative stress. SOD-1,2 and GPx-1 mRNA expression was recovered by pre-treatment with MCE compared with the presence of H₂O₂. Pre-treatment with MCE inhibited phosphorylation of p38 and the JNK pathway and down-regulated cleaved caspase-3 and cleaved PARP by H₂O₂. CONCLUSION: The neuroprotective effects of MCE in terms of recovery of antioxidant enzyme gene expression, down-regulation of MAPK pathways, and inhibition apoptosis is associated with reduced oxidative stress in SK-N-MC cells.