拳参抗氧化活性研究

用清除二苯代苦味酰基（DPPH）自由基、2，2’-连氨-（3-乙基苯并噻唑啉-6-磺酸）二氨盐（ABTS）自由基和铁离子还原／抗氧化能力（FRAP）测定法对拳参体外总抗氧化活性进行评价．并与6-羟基-2，5，7，8-四甲基苯并二氢吡喃-2-羧酸（Trolox）及阳性对照二丁基羟基甲苯（BHT）比较。发现拳参有较好的体外抗氧化活性。甲醇提取物清除DPPH自由基（IC50=3．81μg／mL）的能力远远强于BHT的清除能力（IC50=18．71μg／mL）；清除ABTS自由基能力（IC50=7．65μg／mL）强于BHT（IC50=7．72μg／mL）的清除能力；还原Fe^3＋的能力（FRAP=2009．51±16．44μmol TE／g）最强，强于BHT（FRAP=1581．68±97．41μmol TE／g）。在3种提取物中，甲醇提取物具有最高的抗氧化能力，乙酸乙酯提取物次之。3种方法中，ABTS方法和FRAP方法相关性（R=0．984）最高。

Antioxidant Activity of Extracts from Polygonum bistorta L.

The antioxidant activity of extracts from Polygonum bistorta L.was assayed by three methods,namely,1,1-diphenyl-2-picryl-2-picrylhydrazyl(DPPH) radical scavenging,〔2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid〕 diammonium salt(ABTS) radical scavenging,and ferric reducing / antioxidant power(FRAP) assay.The results were compared with 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid(Trolox) and positive control 2,6-di-tert-butyl-4-methylphenol(BHT).The results showed that P.bistorta L.had good antioxidant activity in vitro.The methanol extract from P.bistorta L.showed higher DPPH and ABTS radical scavenging activity(IC50=3.81 μg / mL and IC50=7.65 μg / mL,respectively) than that of BHT(IC50 =18.71 μg / mL and IC50 =7.72 μg / mL,respectively).It exhibited higher ferric reducing activity(FRAP value=2 009.51±16.44 μmol TE / g) than that of BHT(FRAP value=1 581.68±97.41 μmol TE / g).Among three extracts of P.bistorta L.,the methanol extract showed the highest antioxidant activity,followed by ethyl acetate extract.The results among the three methods were consistent,and the values obtained by ABTS assay were correlated best with those obtained by FRAP assay(R=0.984).