中文摘要：

为优化青钱柳多糖的羧甲基化修饰工艺条件,采用响应曲面Box-Behnken中心组合设计3因素3水平试验,以青钱柳多糖羧甲基化取代度为指标,通过分析各因素交互作用及显著性,探讨氯乙酸浓度、反应温度、时间对多糖羧甲基化修饰的影响。结果表明,青钱柳多糖的羧甲基修饰最优工艺条件为：氯乙酸浓度3 mol/L、反应温度60℃、反应时间4 h,该条件下测得羧甲基化青钱柳多糖取代度为0.76。羧甲基青钱柳多糖CM-CP-1和CM-CP-2在1 mg/mL浓度下对体外超氧自由基的清除率分别为57.52%和53.01%,清除作用随多糖羧甲基化取代度升高而降低,略低于青钱柳原多糖。

英文摘要：

The modificiation parameters for Cyclocarya paliurus polysaccharide carboxymethylation were optimized by using three-factor-three-level Box–Behnken center composite design and response sur fac e methodology.The inf luenc es of parameters including reaction time,temperature and concentration of chloroacetic acid on the degree of substitution（DS） of carboxymethyl Cyclocarya paliurus polysaccharides were studied.Result showed that optimal condition of carboxymethylation of Cyclocarya paliurus polysaccharide was achieved by reaction time for 4 h,reaction temperature of 60 °C and concentration of chloroacetic acid of 3 mol/L.Under these conditions,the substitution degree of the obtained carboxymethylated Cyclocarya paliurus polysaccharide was 0.76.Meanwhile,carboxymethylated Cyclocarya paliurus polysaccharide was tested for its scavenging capacity against superoxide cation free radicals,which showed that the polysaccharide exhibited a strong superoxide cation radical-scavenging ability and also found to be concentration-dependent.The scavenging abilities of CM-CP-1 and CMCP-2 were 57.52% and 53.01% at 1 mg/mL,however,lower than that of original Cyclocarya paliurus polysaccharide.