Antioxidative Activity of Oligopeptides in White Tea

The antioxidant capacity of the oligopeptide-rich white tea was studied by sequencing the amino acids and analyzing the related properties of the extracted oligopeptides. The rate, total reducing power, and effect on the superoxide dismutase activity of HepG₂ cells of the oligopeptides were determined in vitro. The results indicated that the half-inhibitory concentration (IC₅₀) on scavenging DPPH free radicals was 0.170 mg·mL^-1 and that on hydroxyl radicals 0.850 mg·mL^-1. The total reducing power of the oligopeptides was concentration dependent. The in vitro cell experiment on oxidatively damaged HepG₂ cells showed a heightened SOD activity by the oligopeptides indicating a capacity of the functional ingredient in protecting human cells from injury by oxidative stress.