中文摘要：

采用70%丙酮溶液对荸荠皮中抗氧化物质进行提取,得到红棕色浸膏。通过定性及定量方法分析了荸荠皮提取物中可能存在的具有抗氧化活性的物质;采用DPPH自由基法测定了荸荠皮提取物对DPPH自由基的清除能力。结果显示,荸荠皮提取物中含有多酚类和黄酮类等化合物,其多酚含量为3.31%（w/w,以干物质计）。DPPH自由基法显示,荸荠皮提取物具有一定的清除DPPH自由基能力,其清除能力与提取物浓度之间显示出良好的剂量-效应关系。该提取物（IC50值为130.37 ppm）对DPPH自由基清除能力略低于BHT（IC50值为94.16 ppm）。

英文摘要：

A red-yellow extract was obtained from Eleocharis tuberosa peel powder using acetone-water （ 7 ： 3, v/v） and its possible composition was detected by qualitative and quantitative methods. The antioxidant activity of the extract was characterized by the method of 1,1-diphenyl-2-picryl hydrazyl （DPPH） radical. Qualitative and quantitative analyses showed that the extract contained phenolic compounds,flavonoids and some other antioxidant substances with total phenolics content of 3.31%. The extract exhibited certain degree of DPPH radical scavenging activity. There was a strong positive correlation between the scavenging activity and the concentrations. However, the extract had lower IC50 value （ 130, 37 ppm） of scavenging DPPH radical than that of BHT with an IC50 value of 94.16 ppm. Therefore, the extract has lower ability to scavenge DPPH radical than BHT.