中文摘要：

通过中心复合试验优化超声辅助提取连钱草多糖的工艺,以1,1-二苯基-2-苦肼基（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基和2,2’-连氮基-双-（3-乙基苯并噻唑-6-磺酸）自由基（2,2’--azino-bis-（3-ethylbenzothiazoline-6-sulfonic acid）radical,ABTS^＋·）清除能力、Fe^2＋螯合力、铁离子还原抗氧化力（ferric reducing antioxidant power,FRAP）和N,N-二甲基-对苯二胺（N,N-dimethyl-p-phenylenediamine,DMPD）自由基清除能力为指标,研究连钱草多糖的体外抗氧化活性。结果表明,超声辅助提取连钱草多糖的最优工艺为pH 7.2、液固比32∶1（mL/g）、超声功率270 W、超声时间8 min,此条件下多糖提取率在4.95%-5.12%范围内。体外抗氧化活性结果显示,连钱草多糖DPPH自由基清除能力为（0.51±0.04）μmol Trolox/mg,ABTS^＋·清除能力为（0.69±0.04）μmol Trolox/mg,Fe^2＋螯合力为（0.51±0.29）μmol EDTA/mg,FRAP值为（3.45±0.03）μmol Trolox/mg,DMPD自由基清除能力为（0.17±0.01）μmol Trolox/mg。

英文摘要：

In this study,we optimized the ultrasound-assisted extraction of polysaccharides from the dried aboveground part of Glechoma longituba（Nakai） Kupr. by response surface methodology（RSM） based on central composite design and measured the antioxidant activities of the extracted polysaccharides using 1,1-diphenyl-2-picrylhydrazyl（DPPH） radical scavenging,2,2＇-azino-bis（3-ethylbenzthiazoline-6-sulfonic acid radical（ABTS^＋·） scavenging,Fe^2＋ chelating activity,ferric reducing antioxidant power（FRAP）,and N,N-dimethyl-p-phenylenediamine radical scavenging methods. The optimal extraction conditions were obtained as follows： pH,7.2; liquid-to-solid ratio,32：1（mL/g）; ultrasonic power,270 W; and ultrasonic time,8 min. Under these conditions,the yield of polysaccharides was 4.95%–5.12%. The extracted polysaccharides exhibited powerful antioxidant activities. The DPPH radicals and ABTS^＋· scavenging activities,Fe^2＋ chelating activity,FRAP value and DMPD radical scavenging capacity were（0.51 ± 0.04） μmol Trolox equivalent（TE）/mg,（0.69 ± 0.04） μmol TE/mg,（0.51 ± 0.29） μmol EDTA-2Na equivalent（EE）/mg,（3.45 ± 0.03） μmol TE/mg and（0.17 ± 0.01） μmol TE/mg,respectively.