In vitro chemo-protective effect of bioactive peptide lunasin against oxidative stress in human HepG2 cells

Lunasin is a peptide with proven properties against cancer and cardiovascular diseases. Relevant amounts of lunasin have been found in liver of rats fed lunasin-enriched diets, indicating its potential bioactive effect in this tissue. This study investigated the stability of lunasin in human liver HepG2 cells, and its chemoprotective effect against oxidative stress induced by tert-butylhydroperoxide. Pre-treatment of cells with lunasin (0.5-10 mu M) significantly prevented the increased reactive oxygen species (ROS) generation (122% compared to 190% in stressed cells), and glutathione peroxidase and catalase activities, as well as the depletion of reduced glutathione. By restraining ROS overproduction, lunasin evoked a decline in carbonyl groups, and a significant recovery from cell death by apoptosis. These findings suggest that lunasin, at physiological concentrations, might confer a significant chemoprotective effect against oxidative stress-associated liver disorders. In addition, fragments released after hydrolysis of lunasin by cell enzymes might contribute to the observed antioxidant effects. (C) 2014 Elsevier Ltd. All rights reserved.