采用超声结合水提的方法提取东革阿里的多糖，通过L9(34)正交试验确定最佳提取条件。利用柱层析纯化得到一种含糖醛酸的新型多糖组分Ali-1；通过分子量检测和单糖组成分析对Ali-1进行基本结构表征；采用氧自由基吸收能力(ORAC)和人血红细胞溶血模型测定多糖的抗氧化活性，并同时测定红细胞内活性氧物质（ROS）、丙二醛（MDA）水平和过氧化氢酶（CAT）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）抗氧化酶活力的变化。结果表明：东革阿里多糖最佳提取条件为料液比1:40、浸提温度95 ℃、超声波破碎功率300 W、浸提时间2 h，最适条件下东革阿里的粗多糖得率为10.09%；Ali-1的平均分子量为14.3 ku，主要由木糖、阿拉伯糖、葡萄糖醛酸和半乳糖醛酸组成，其摩尔比为：4.43:1.10:1:1.14；Ali-1的QRAC值为302.48±2.71 μmol Trolox/g，且Ali-1的预处理使得AAPH损伤的人血红细胞内的ROS和MDA水平降低，使红细胞恢复到正常状态；虽SOD、GSH-Px和CAT平均酶活力降低，但结果表明较弱的红细胞也受到了保护。综上所述，经分离纯化后的东革阿里多糖组分Ali-1可以保护人血红细胞免受AAPH的损伤，具有较好的抗氧化活性。

A crude polysaccharide extract was obtained from Eurycoma longifolia via ultrasound-assisted water extraction, and the optimal extraction conditions were determined by the L9(34) orthogonal test. A novel polysaccharide component containing uronic acid, Ali-1, was obtained through purification by column chromatography. The basic structure of Ali-1 was determined through analyses of its molecular weight and monosaccharide composition. The antioxidant activity of Ali-1 was evaluated based on the oxygen radical absorption capacity (ORAC), as well as the changes in the levels of reactive oxygen species (ROS), malondialdehyde (MDA) and catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) of red blood cells in the human erythrocyte hemolysis model. The results showed that the optimal extraction conditions for the crude polysaccharide were: ratio of material to liquid 1:40, extraction temperature 95 oC, ultrasonic power 300 W, extraction time 2 h. The yield of the crude polysaccharide from Eurycoma longifolia was 10.09% under the optimum conditions. Ali-1 had an average molecular weight of 14.3 ku and was mainly composed of xylose, arabinose, glucuronic acid and galacturonic acid at a molar ratio of 4.43:1.10:1:1.14. The ORAC value of Ali-1 was 302.48±2.71 μmol Trolox equivalents/g. Pretreating with Ali-1 could effectively reduce the levels of MDA and ROS in the 2-2′-azo-bis- (2-amidinopropane) dihydrochloride (AAPH)-injured erythrocytes, restore the erythrocytes to the normal state, and protect the weak erythrocytes (even though their average SOD, GSH-Px and CAT activities decreased). In summary, the isolated and purified polysaccharide Ali-1 from Eurycoma longifolia can protect human red blood cells against AAPH-induced injury and exhibit good antioxidant activity.

广东省科技计划项目（2017A020108006；2016B010121014）