Antioxidant activity of soybean peptides on human hepatic HepG2 cells

Soybean is an interesting source of bioactive peptides useful for the development of functional foods and nutraceuticals. In this study, the antioxidant activity of peptic (P) and tryptic (T) soybean hydrolysates was characterized. Results suggest that both hydrolysates are able to scavenge DPPH radical. Moreover, after induction of oxidative stress by using H₂O₂, either Soybean P or T pre-treatment reduces the ROS, lipid peroxidation, and NO levels in human hepatic HepG2 cells. HepG2 cells, exposed to H₂O₂ alone, produce a significant augmentation of intracellular reactive oxygen species (ROS) levels by 29.5%, with the consequence of an augmentation of cellular lipid peroxidation levels up to 112.4 ± 0.5%. The pre-treatment with soybean hydrolysates restores the basal level of ROS and induces a reduction of cellular lipid peroxidation. The antioxidant ability of Soybean P and T are also confirmed by their ability to reduce the H₂O₂-induced NO levels in HepG2 cells.