天门冬多糖的化学结构及体外抗氧化活性

目的　研究天门冬多糖ACP1的化学结构及体外抗氧化活性。方法　用沸水提取天门冬块根粉粗多糖，经DEAE-cellulose及Sephadex G-150柱色谱纯化得纯多糖ACP₁。经酸全水解，PC，GC，IR，高碘酸氧化、Smith降解、CrO3氧化、全甲基化，1H及¹³CNMR等研究化学结构。并利用NADH-PMS-NBT系统产生，Fe2+-Vit C系统产生*OH，H₂O₂诱导红细胞氧化溶血来研究ACP₁清除自由基、抗氧化活性。 结果　ACP₁的分子量为1.04×10⁵, 比旋光度为［α］¹⁵_D=+64°（c 0.64,H₂O）。ACP₁是由Gal及Glc组成，摩尔比为1.00∶0.87。ACP₁是由8个β-（1→4）Gal及6个α-（1→6）Glc连接构成主链，并在其中1个Gal残基的3-O位上接有1个α-Glc残基的支链。ACP₁体外可清除NADH-PMS-NBT系统产生的超氧阴离子自由基，降低Fe²⁺-Vit C引起的小鼠肝微粒体脂质过氧化产物丙二醛的含量，抑制H₂O₂诱导的大鼠红细胞氧化溶血。结论　ACP₁为一半乳萄聚糖，有清除自由基及抗脂质过氧化活性。

THE CHEMICAL STRUCTURE AND ANTIOXIDATIVE ACTIVITY OF POLYSACCHARIDE FROM ASPARAGUS COCHINCHINENSIS

AIM　To study the structure and antioxidative activity of polysaccharide from Asparagus cochinchinensis. METHODS AND RESULTS　the tube roots of Asparagus cochinchinensis was extracted with boiling water. From the extract, a polysaccharide, ACP₁ was separated using DEAE-cellulose and purified by Sephadex G-150 column chromatography. Its structure was studied by composition analysis, IR, periodate oxidation analysis, Smith degradation, CrO₃ oxidation, methylation analysis, ¹H and ¹³CNMR analysis etc. ACP₁ was found to be composed of Gal and Glc, in the ratio of 1.00∶0.87, with the molecular weight of 10.4×10⁴ and ［α］15D=+64(c 0.54, H2O). ACP₁ contained a backbone composed of 8β-(1→4) linked D-galactopyranosidic and 6α-(1→6) linked D-glucopyranosidic linkages, a glucosyl branch is attached to 3-O of a galactosyl residues of the main chain. The superoxide anion() produced by NBT-PMS-NADH system was scavenged and the lipid peroxidation induced by Fe²⁺-ascorbic acid in mouse liver microsome was inhibited, the hemolysis of rat RBC induced by H₂O₂ was antagonized. CONCLUSION　ACP₁ is a galacto-glucan and has distinctive effect of antioxidation.