灵芝多糖乙酰化及其抗氧化活性研究

目的 通过化学修饰改变灵芝多糖分子结构，并研究其体内抗氧化活性。方法 乙酰化修饰灵芝多糖（Ganoderma lucidum polysaccharide，GLP），得到GLP乙酰化衍生物（GLP acetyl derivatives,GLPa）；将昆明种小鼠随机分成空白对照组，阳性对照组，GLP高、低剂量组及GLPa高、低剂量组，测定小鼠血清和肝脏丙二醛（malondialdehyde，MDA）、总抗氧化能力（total antioxidant capacity，T-AOC）和过氧化氢酶（catalase，CAT）；建立高脂血症大鼠抗氧化损伤模型，考察GLP及GLPa的抗氧化能力。结果 GLPa及GLP均可以显著提高正常小鼠肝组织CAT活力及T-AOC，降低小鼠血清及肝脏MDA含量，GLPa抗氧化活性明显优于GLP，且与给药剂量相关。此外，GLPa及GLP还可以显著降低四氧嘧啶致高脂大鼠的氧化损伤程度，提高其血清超氧化物歧化酶活力及肝脏T-AOC，并降低其血清MDA含量。结论 乙酰化修饰可显著提高灵芝多糖的抗氧化活性。

Acetylation of Ganoderma lucidum Polysaccharide and Its Antioxidant Activities

Objective To change the molecular structure of Ganoderma lucidum polysaccharide (GLP) through chemical modification, and to investigate its antioxidant activities in vivo. Methods GLP was modified by acetylation to obtain the acetyl derivative GLPa. Kunming mice were randomly divided into blank control group, positive control group, high- and low-dose GLP groups, and high- and low-dose GLPa groups. The malondialdehyde (MDA), total antioxidant capacity (T-AOC), and catalase (CAT) in the serum and liver were measured; the model of anti-oxidative damage was established in hyperlipidemic rats to investigate the antioxidant capacity of GLP and GLPa. Results GLPa and GLP significantly increased the activity of CAT and T-AOC in the liver tissue of normal mice and reduced the levels of MDA in the serum and liver; the antioxidant activity of GLPa was better than that of GLP and was dose-dependent. In addition, GLPa and GLP significantly reduced the degree of oxidative damage induced by alloxan in the hyperlipidemic rats, increased the activity of serum superoxide dismutase and liver T-AOC, and reduced the serum level of MDA. Conclusion Acetylation can significantly improve the antioxidant activities of GLP.