【作者】 戎茜；

【导师】 安利国； 庄文忠；

【作者基本信息】 山东师范大学 ， 细胞生物学， 2003， 硕士

【摘要】 大量资料研究证实自由基与多种疾病的发生、发展有关，对肝组织病理损伤的机制之一是自由基引发的过氧化作用，细胞的损伤程度可由抗氧化机制来调节。由于化学合成制品大多有毒副作用，因此从天然动植物中寻求来源广泛、低毒或无毒的抗氧化或保肝的有效成分具有重要意义。 芦荟是一种药理活性广泛的传统药用植物。本文用热水浸提法从库拉索芦荟（Aloe barbadensis）鲜叶中分离、提取芦荟多糖，并研究库拉索芦荟原汁及其多糖的抗氧化作用和保肝作用。主要结果如下： 1．毛细管电泳分析显示库拉索芦荟多糖的单糖组成以甘露糖为主，含有部分阿拉伯糖和少量海藻糖。 2．用比色法体外检测库拉索芦荟原汁及其多糖清除活性氧自由基的能力，结果证实芦荟原汁及其多糖体外具有显著清除羟基自由基和超氧阴离子自由基的作用，且呈一定浓度或剂量依赖性。100％芦荟原汁对羟自由基清除率达95.28％，100μL芦荟原汁对超氧阴离子清除率达77.48％。20mg／mL多糖对羟基自由基清除率达42.60％，对超氧阴离子自由基清除率达84.96％。芦荟原汁体外还能显著抑制肝组织自发性脂质过氧化中MDA的生成，而芦荟多糖对MDA的抑制效果不明显。 3．分别用库拉索芦荟原汁及其多糖灌胃小鼠，连续10天后，小鼠肝匀浆中MDA的生成较正常组显著减少，同时SOD活性显著提高，而多糖的效果不明显。说明芦荟原汁体内有显著抗氧化能力，而芦荟多糖的体内抗氧化能力不强。 4．分别用灌胃或腹腔注射的方法预处理小鼠，再以10mL／kg的剂量腹腔注射0.1％四氯化碳油溶液对肝造成急性损伤，观察库拉索芦荟原汁及其多糖对肝组织的保护作用。结果表明芦荟原汁和芦荟多糖经灌胃或腹腔注射均能显著降低血清谷丙转氨酶（GPT）水平，抑制肝脏CCl₄损伤后脂质过氧化产物MDA的产生，并能明显改善CCl₄损伤引起的肝组织结构病变（如坏死、炎症、肿胀）和线粒体变性等亚细胞结构病变，这表明库拉索芦荟原汁及其多糖都有保肝作用，其对肝脏的保护作用和抗氧化有关。 本实验结果对进一步开发利用库拉索芦荟的药用、食用价值具有一定参考价值。更多还原

【Abstract】 There is an extensive evidence to implicate that free radical is related to origin and development of many diseases. The peroxidantion induced by free radical is one of the machanism of pathological injury in liver tissue. The degree of injury may be regulated by antioxidant. In consider of the toxicity and side-effect of chemosynthesis product, it is important to exploit effective component with low-toxicity or untoxicity from natural animal or plant.Aloe is recognised as a traditional medical plant for its broad pharmacological activities. In this paper we isolate aloe polysaccaride from fresh leave of Aloe Barbadensis by means of hot-water extracting. Then the antioxidant and hepatoprotective effects of aloe and its polysaccharide were investigated. The main conclusions are as followed:1. The result of HPCE showed that polysaccaride of Aloe Barbadensis is composed of mannose, trehalose, arabinose.2. We choosed spectrophotometer method to study the scavenging effect of aloe and its polysaccharide on reactive oxidative free radical. In vitro, it was shown that both crude juice of aloe (CJA) and aloe polysaccharide (AP) were found to have significant capacity of scavenging free radical in a concentration or dose-dependant manner. The rates of scavenging effects on hydroxyl free radical and superoxide anion free radical by CJA with the concentration of 100% or dosage of lOOul were 95.28% and 77.48% respectively. While the rates of scavenging effects on hydroxyl free radical and superoxide anion free radical by AP 20mg/mL were 42.60% and 84.96% respectively. In addition, a significant inhibition of malondialdehyde (MDA) generation spontaneously in liver homogenate is also oberserved in crude juice of aloe in vitro, but its polysaccharide has no effect to be identified .3. Mice were administered intragastric (ig) CJA and AP for 10 consecutive days. Compared with the normal group, ,mice administered with CJA showed a significantdecrease in MDA production in liver homogenate and a significant increase in the activity of SOD simultaenously. But aloe polysaccharide has no significant influence to be found.4. To observe the hepatoprotective effects of Aloe Barbadensis and its polysaccharide, mice were pretreated by means of intragastric or intraperitonelly injection. Seven days later, they were injected 0.1% (V:V) carbon tetracholoride (CCl4) intraperitonelly at the dose of 10mL/kg.bw which induce acute hepatic injury. We found that the glutamic-pyruvic transaminase (GPT) level in serum and the MDA cotent in liver tissue were significantly decreased. Furthermore, the deterious lesions of hepatic tissue microstructure and sub-microstructure such as cell narcrosis, inflammation, mitochondrial denaturing induced by CCl4 were marked improved. These results suggested that both CJA and AP have hepataprotective function. The hepataprotective effect is related to its antioxidant activity.These results will provide some reference for making more exploitation on aloe.更多还原