Abstract: The anti-oxidative effect and mechanism of RSPS were studied. The K3[Fe(CN)6], TCA system and the crude lipoxygenase were used to evaluate RSPS's capacity of deoxidizing and its inhibition on lipoxygenase. The reagent kits were used to analyse the content of malondialdehyde(MDA) and reactive oxygen species (ROS), and the swelling of mice liver mitochondria was observed in the spectrophotometric method. The results showed that RSPS was a good reducer, and the anti- ROS unit of 2.00 mg·ml-1 RSPS was 94.03, and the inhibiting rate of 2.00 mg·ml-1 RSPS on lipoxygenase was 22.8% in some chemically modified systems. In vitro, 2.00 mg·ml-1 RSPS made the radical-induced swelling of mice liver mitochondria be lower than the swelling of mice liver mitochondria without inducement. The inhibiting rate of 2.00 mg·ml-1 RSPS on radical-induced MDA formation was 30.3% in mice liver mitochondria, while 54.7%(incubation), 32.0%(incubation with Fe2+) and 84.5%(incubation with H2O2) in liver homogenate, respectively. The anti- ROS unit of mice serum, added with 10.00 mg·ml-1 RSPS, was 1340.13. In vivo, there was a significant difference(P<0.01) between the controlled group and the intra- peritoneal injected group (with RSPS 400mg·kg-1 bw·d-1, 12 d) in MDA value in mice liver homogenate. All the results above showed that RSPS has anti-oxidation effect in vitro and in vivo, the high capacity of deoxidising and inhibiting the activity of enzymes associated with oxidation maybe the possible mechanism of RSPS to inhibit oxidation.

Key words: Polysaccharide from rapeseed(RSPS), Antioxidation, Chemically modified systems