软枣猕猴桃多糖的体外抗氧化活性

in vitro Antioxidant Activity of Polysaccharides from Actinidia arguta Sieb. et Zucc. Fruits

利用水提醇沉法提取软枣猕猴桃粗多糖,经脱蛋白、脱脂,软枣猕猴桃粗多糖的提取率为1.41%。利用DEAE-52纤维素离子交换层析对软枣猕猴桃多糖进行初步分离,得到4种软枣猕猴桃多糖组分。利用SephadexG-200凝胶柱层析对组分Ⅱ和Ⅲ实现了完全分离。通过测定清除自由基能力,评价软枣猕猴桃多糖组分Ⅱ的抗氧化活性。结果表明:软枣猕猴桃多糖对DPPH自由基及烷基自由基(R)有较强的清除能力,IC50值分别为0.497、0.547mg/mL。在受试范围内,随软枣猕猴桃多糖质量浓度的增加,清除能力增强,当软枣猕猴桃多糖质量浓度达到1mg/mL时,其对DPPH自由基及R的清除率分别达到86.4%、87.1%,与VC的清除率相近。软枣猕猴桃多糖对羟自由基(OH)有一定的清除能力,IC50值为0.668mg/mL。其清除能力随多糖质量浓度的增加而有所增加,但其对OH的清除率较VC有一定的差距。软枣猕猴桃多糖对O-2.的清除率较低,清除能力较弱。由此可见,软枣猕猴桃多糖具有较强的抗氧化活性。

Crude polysaccharides from Actinidia arguta Sieb.et Zucc.fruits were extracted by hot water extraction and ethanol precipitation,deproteinized and defatted and the yield of crude polysaccharides was found to be 1.41%.The crude polysaccharide extract was separated by DEAE-cellulose 52 ion exchange chromatography to obtain four fractions（Ⅰ,Ⅱ,Ⅲ and Ⅳ）.Complete separation of fractions Ⅱ and Ⅲ was achieved by Sephadex G-200 column chromatography.The antioxidant activity of fraction Ⅱ was investigated by measuring free radical scavenging activity.Polysaccharide fraction II was found to have strong radical scavenging activity against DPPH and alkyl radicals with an IC50of 0.497 mg/mL and 0.547 mg/mL,respectively.Its radical scavenging activity increased with increasing concentration within the concentration range investigated and the scavenging rate at a concentration of 1 mg/mL was 86.4% and 87.1% for DPPH and alkyl radicals,respectively,which was comparable to that of vitamin C.Moreover,this fraction also had radical scavenging activity against hydroxyl radical with an IC50of 0.668 mg/mL in a concentration-dependent manner but was inferior to vitamin C.However,its radical scavenging activity against superioxide anion radical was weak.Based on the above results,we conclude that polysaccharide fraction Ⅱ has potent antioxidant activity.