多糖中金属离子对其抗氧化活性及抗肿瘤活性的影响

采用水提醇沉法制备香菇、海带、枸杞多糖粗品,Sevage法除蛋白制得初级纯化多糖。利用EDTA-2Na去除多糖粗品和纯品中的金属离子,比较去除前、后多糖抗氧化活性及抗肿瘤活性的变化。结果表明:3种多糖均含有Al、Ca、Mn等多种金属元素,只是含量各不相同。去除金属离子后,多糖对ABTS自由基、DPPH自由基的清除能力均下降,对羟自由基的清除能力变化不一。其中枸杞多糖质量浓度为600μg/mL时抗氧化活性变化最为显著,ABTS自由基清除率由26.31%降至17.25%,DPPH自由基清除率由59.80%降至38.40%。枸杞多糖纯品在去除金属后对人乳腺癌细胞MCF-7的体外抑制活性呈下降趋势。结论:多糖中的金属元素是多糖活性中心构成的一部分,对其活性具有重要影响。

Effects of Metal Ions in Polysaccharides on Their Antioxidant Activity and Antitumor Activity

Lentinan, Laminarin and Lycium barbarum polysaccharide(LBP) were extracted by ethanol subsiding method and deproteinized by Sevage method. EDTA-2 Na was used to remove the metal ions from crude polysaccharide and deproteinized polysaccharide. The antioxidant activity and antitumor activity of the polysaccharides were investigated by various assays, and compared with those of metal ions loss. The results showed that three fractions contain various intrinsic metal ions including Al, Ca, Mn with different amount. The ABTS radical scavenging, DPPH radical scavenging ability decreased after the metal ions removal. The change of hydroxyl radical scavenging ability was inconsistent among the investigated polysaccharides. Among them the activity of LBP decreased most significantly at 600 μg/mL, the scavenging activity of LBP on the ABTS radical decreased from 26.31% to 17.25% and the DPPH radical decreased from59.80% to 38.40%. The antitumor activity against MCF-7 human breast cancer cells also decreased after the deproteinized LBP was treated by EDTA-2 Na. We hence proposed that the intrinsic metal ions are a part of the active center in polysaccharides, which has an important effect on its activities.