羧甲基化川芎多糖的制备及抗氧化活性

Preparation and Antioxidant Activity of Carboxymethylation Polysaccharides from Ligusticum Chuanxiong

为提高川芎多糖的水溶性,以α-氯乙酸为羧甲基化试剂半合成羧甲基化川芎多糖,其结构由红外光谱进行表征,高效凝胶渗透色谱法测定其相对分子质量,并考察其对1,1-二苯基-2-苦基肼自由基和邻苯三酚自氧化反应产生的超氧阴离子自由基和羟自由基的体外清除率。结果表明:羧甲基化反应的最佳条件为反应温度70℃,川芎多糖与α-氯乙酸质量比为25∶1,反应溶剂为75%乙醇,反应时间3h,在该条件下,羧甲基化川芎多糖取代度为0.68,分子量为175 655Da。川芎多糖(LCXP)对DPPH自由基、超氧阴离子自由基和羟自由基清除率的IC50值分别为25.63mg/mL、4.52mg/mL和5.38mg/mL,羧甲基化川芎多糖(CM-LCXP)对DPPH自由基、超氧阴离子自由基和羟自由基清除率的IC50值分别为9.09 mg/mL、4.16mg/mL和5.01mg/mL。结论:川芎多糖经羧甲基化修饰后明显提高多糖的溶解性,增强其对DPPH自由基的清除活性,对超氧阴离子自由基和羟自由基的清除作用没有明显差异。但与VC相比,川芎多糖和羧甲基化川芎多糖对DPPH自由基、超氧阴离子自由基和羟基自由基的清除作用较弱。

The relative molecular mass and O-2 ＆#183;,DPPH and ! OH scavenging rate of semisythetic carboxymethylation L.Chuanxiong polysaccharides were determined by HPGPC and spectrophotometer to improve water solubility of L.Chuanxiong polysaccharides.The substitute ratio and molecular weight of carboxymethylation Ligusticum Chuanxiong polysaccharides under the optimum carboxymethylation reaction conditions of 25∶1 of L.Chuanxiong polysaccharides/α-chloroacetic acid,75% alcohol and 70℃for 3 h is 0.68 and 175 655 Da separately.IC50 of DPPH,O-2 and ! OH scavenging rate of L.Chuanxiong polysaccharides is 25.63 mg/mL,4.52 mg/mL and 5.38 mg/mL but IC50 of DPPH,O-2 and ! OH scavenging rate of carboxymethylation L.Chuanxiong polysaccharides is 9.09 mg/mL,4.16 mg/mL and 5.01 mg/mL respectively.In conclusion,carboxymethylation Ligusticum Chuanxiong polysaccharides improves the solubility of polysaccharides obviously and DPPH scavenging rate but has no significant difference in O-2 and ! OH scavenging rate compared with L.Chuanxiong polysaccharides.The DPPH, O-2 and ! OH scavenging rate of Ligusticum Chuanxiong polysaccharides and carboxymethylation L.Chuanxiong polysaccharides is weak compared with VC.