Abstract: Objective: To investigate the antioxidant activity in vitro and the protective effect of Silybum marianum seed oil on oxidative damage induced by D-galactose in mice. Methods: The scavenging capacity for DPPH and hydroxyl radicals and the total antioxidant capacity were determined to explore in vitro antioxidant activity of the seed oil. Furthermore, the effects of the seed oil on serum antioxidant enzyme activities and liver morphology were examined to evaluate its protective effect on oxidative damage in mice. Results: Silybum marianum seed oil had antioxidant capacity in vitro in a dose-dependent manner. It could significantly increase the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) in mice serum and protect the integrity of liver cell morphology in mice. Conclusion: Silybum marianum seed oil has antioxidant activity in vitro and possesses a protective effect on D-galactoseinduced oxidative damage in mice.

Key words: Silybum marianum seed oil, in vitro antioxidant activity, oxidative damage, antioxidant enzyme