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采用水/甲醇混合溶剂浸泡提取旱莲草的多糖组分,利用硅胶柱层析和中压液相色谱,对多糖进行分离纯化,纯化后的多糖组分经薄层层析分析发现,这些多糖主要组成单糖均为葡萄糖和果糖。旱莲草多糖在总还原能力、总抗氧化能力和FRAP抗氧化能力测试中均显示较好的活性,能够有效清除羟自由基和DPPH自由基,在1.5 mg/m L的浓度下,对羟自由基的清除效率为(12.33~56.81)%,粗多糖组分在1 mg/m L的浓度下对DPPH自由基的清除效率为(17.88~84.47)%,精分多糖组分在5 mg/m L的浓度下,对DPPH自由基的清除效率为(18.64~91.35)%;极性小的多糖抗氧化活性显著优于极性大的多糖,抗氧化活性最高可达后者的11倍之多;粗多糖组分的抗氧化活性一般优于纯化后的相应精多糖组分,这说明旱莲草的不同多糖分子之间可能存在协同抗氧化作用。
The polysaccharide components of Eclipta prostrata were extracted by soaking in a mixed solvent of water and methanol. The polysaccharides were separated and purified by silica gel column chromatography and medium pressure liquid chromatography. The purified polysaccharide fractions were analyzed by TLC. The main components of monosaccharides are glucose and fructose. Eclipta polysaccharide showed good activity in total reducing ability, total antioxidant capacity and FRAP anti-oxidation ability test, which could effectively scavenge hydroxyl radical and DPPH radical. Under the concentration of 1.5 mg / m L, The removal efficiency of free radical was (12.33 ~ 56.81)%, the DPPH radical scavenging efficiency of crude polysaccharide fraction was (17.88 ~ 84.47)% at the concentration of 1 mg / The removal efficiency of DPPH radical was (18.64 ~ 91.35)% under the concentration of m L; the activity of the polysaccharide with smaller polarity was significantly better than that of the polar polysaccharide, and the antioxidant activity was up to 11 times The antioxidant activity of crude polysaccharides was generally better than that of purified polysaccharides, which indicated that synergistic antioxidant activity may exist between different polysaccharides of Eclipta prostrata.