Diethylnitrosamine-induced redox imbalance in rat microsomes: protective role of polyphenolic-rich extract from Sorghum bicolor grains.

BACKGROUND: This study investigates the protective role of polyphenolic-rich extract from Sorghum bicolor against diethylnitrosamine (DEN)-induced redox imbalance in rat microsomes.

METHODS: Reactive oxygen species (ROS) scavenging potentials of the polyphenolic extract from S. bicolor (0.2-1.0 mg/mL) was investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide ion, hydrogen peroxide, hydroxyl radical, and ferric ion reducing system. The detoxification of ROS was evaluated in DEN-induced redox imbalance in rat microsomes.

RESULTS: Sorghum bicolor polyphenolic extract at 1.0 mg/mL scavenged the DPPH, superoxide ion, hydrogen peroxide, and hydroxyl radical at 75%, 76%, 79%, and 81%, respectively; it also reduced ferric ion significantly. The polyphenolic extract significantly (p<0.05) attenuated DEN-mediated decrease in the activities of ROS detoxifying enzymes (superoxide dismutase, catalase, glutathione peroxidase and reductase, and glucose-6-phosphate dehydrogenase). The concentrations of malondialdehyde, conjugated dienes, lipid hydroperoxide, protein carbonyl, and percentage DNA fragmentation in DEN-treated microsomes were significantly reduced by the polyphenolic extract.

CONCLUSIONS: The results of the present study indicated that S. bicolor polyphenolic extract possessed in vitro antioxidant activity and protected microsomes from DEN-mediated oxidative stress by scavenging free radicals and ROS scavenger and inducer of ROS detoxifying enzymes.