采用水提醇沉法，通过单因素和正交试验研究青北五味子多糖(polysaccharides from immature Schisandra chinensis (Turcz.) Baill，PIS)的提取工艺，并以VC为参照物，考察脱蛋白前后PIS的抗氧化活性。结果表明：从青北五味子中提取多糖的最适宜工艺条件是料液比1：30(g/mL)、提取温度90℃、提取时间2h、提取3次。用Sevag法对PIS 进行初步提纯，UV扫描检测表明去蛋白后PIS中基本不含有蛋白质与核酸。利用红外光谱法对纯化PIS进行表征，证明其具备一般多糖类物质的光谱特征。脱蛋白前后PIS对羟自由基和超氧阴离子自由基均具有一定的清除能力，且脱蛋白后的PIS清除自由基的效果更好，其抑制O2¯•和•OH的IC50分别为66.03、6.49mg/mL，说明纯化PIS具有优良的清除•OH的能力。但它们的抗氧化活性都不如VC。%The extraction of water-soluble polysaccharides from immature fruits of Schisandra chinensis (Turcz.) Baill was optimized by one-factor-at-a-time and orthogonal array design methods. Crude polysaccharides were separated from the resulting extract by means of ethanol precipitation and deproteinized by Sevag method. The antioxidant activity of crude and purified polysaccharides was investigated and compared with that of VC. The optimum extraction conditions were found to be three cycles of extraction at 90℃for 2 h with a solid-to-liquid ratio of 1:30 (g/mL). Purified polysaccharides contained nearly no protein or nucleic acid as demonstrated by UV spectroscopic analysis and had common spectral characteristics of polysaccharides as showed by infrared spectroscopic analysis. Both polysaccharide samples had scavenging effects against hydroxyl and superoxide anion free radicals and the free radical scavenging effect of deproteinized polysaccharides was stronger. The corresponding IC50 values against superoxide anion and hydroxyl free radicals were 66.03 mg/mL and 6.49 mg/mL, respectively, suggesting purified polysaccharides to be a strong scavenger against hydroxyl free radicals. Crude and deproteinized polysaccharides, however, had weaker antioxidant activity than VC.
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