To evaluate antioxidative and preventive effects of sea tangle extract on selenite-induced cataract formation.

Eighty SD rat pups were randomized into 8 groups. Group 1 received no injection of reagent (normal); Group 2 to 8 received injection of selenite (15 µmol/Kg, s.c.) was injected. In group 2 (control) and group 3, normal saline (i.p.) and ascorbic acid (i.p.) was injected on days 3~31. In groups 4~8, sea tangle extract (i.p.) was injected at a concentration of 12.5, 25, 50, 100, 200 mg/kg, respectively. Development of cataract was assessed and photographed weekly under slit lamp. Rat lenses were analyzed for antioxidant enzymes, glutathione peroxidase (GPx), superoxide dismutase and malondialdehyde. Furthermore, an amino acid analysis of sea tangle extract was performed.

Significant differences ( p <0.05) were seen in cataract development in group 7. Dense nuclear cataracts developed in 8 of 10 of the control group (group 2); Group 4~8 developed nuclear cataract with proportion of 6/10, 3/10, 2/10, 1/10, and 6/10 rats. In sea tangle injected group, levels of GPx were higher than in the ascorbic acid and control groups. In particular, group 7, injected with 100 mg/kg of sea tangle extract, showed significantly high level of enzyme. Results of the amino acid analysis showed sea tangle includes glutamate-glycine-cysteine, major constituents of glutathione (GSH).

The glutamate-glycine-cysteine in sea tangle is supposed to increase the level of lens GSH and this may contribute to lowering cataract development. This study strongly supports the activity of sea tangle as an endogenous antioxidant and anticataract agent.