Abstract: In this study an active substance of Gynura bicolor DC, which could scavenge free oxygen radical, was extractedwith different solvents. It indicated that the extracts with water had better effects to the radicals than with other solvents. The experiments design was drawn by orthogonal test further. It was found that the extracting results were best when ratio of solid to liquid was 40 at 30℃ for 2 hours. The anti-oxidant activity of Gynura bicolor DC was compared with VC, Chinese cabbage, celery, green pepper and purple cabbage too, the results showed that the extracts with water had strong effect upon scavenging O•2, as the concentration reached 750μg/ml. It could scavenge 73.04% of O•2.

Key words: Gynura bicolor DC, oxygen free-radical, scavenging - -