不同分子量坛紫菜多糖的制备及其抗衰老活性研究

IOCAS-IR > 海洋环流与波动重点实验室

	不同分子量坛紫菜多糖的制备及其抗衰老活性研究
其他题名	PREPARATION OF DIFFERENT MOLECULAR WEIGHT POLYSACCHARIDES FROM PORPHYRA HAITANENSIS AND THEIR ANTI-AGING ACTIVITIES
	赵婷婷
学位类型	博士
	2007-06-02
学位授予单位	中国科学院海洋研究所
学位授予地点	海洋研究所
关键词	坛紫菜多糖降解抗氧化活性 T、b淋巴细胞增殖耐疲劳寿命生命活力老年痴呆
摘要	坛紫菜（Porphyra haitanensis），属红藻门（Rhodophyta），红毛菜科（Bangiacease）紫菜属（Porphyra），是我国大规模养殖的重要经济海藻之一，主要产于我国南方沿海如福建、广东、浙江等地。紫菜作为中药，具有“补肾养心，利水消肿”的功效，实验室前期所作的工作表明，坛紫菜多糖具有良好的抗衰老作用。分子量对多糖生物活性有重大影响，本文以福建沿海的坛紫菜为原料，对坛紫菜多糖（P）的降解方法和该紫菜多糖的抗衰老活性与分子量的关系展开了研究。本论文首次将植物生长发育过程中发生的抗坏血酸和过氧化氢反应体系应用于坛紫菜多糖的降解。抗坏血酸和过氧化氢的浓度及两者的比例是该降解方法的主要影响因素。采用该法制备了分子量分别为50、30、13、8.2和2.7 kD 的P1、P2、 P3、P4和P5五种产品。其中P1、P2和P3产品的红外图谱与原料多糖的红外图谱一致，表明这两种多糖的化学结构在降解过程中并未发生改变，而P4和P5样品的红外图谱显示该样品中出现了少量的羧基。本论文还首次对各产物进行了抗氧化、免疫调节、抗疲劳、延长寿命、抗老年痴呆等活性的筛选与研究，具体结果如下：采用化学法对五种降解多糖和原料多糖的抗氧化活性进行研究。结果表明分子量对坛紫菜多糖清除各种自由基能力的影响是不同的。降解之后，坛紫菜多糖清除超氧阴离子的能力有所下降，与金属离子的螯合能力几乎全部丧失，但是多糖清除羟基自由基的能力变化甚微。降解之后，坛紫菜多糖清除有机自由基的能力和还原能力显著提高，随分子量的降低这两种能力明显加强，其中P4样品清除有机自由基能力最强，而分子量最小的P5样品还原能力最突出。通过测定T、B淋巴细胞增殖率考察了五种降解多糖和原料多糖的免疫调节作用。研究表明：不同分子量坛紫菜多糖均具有免疫调节作用，可显著促进小鼠脾脏T淋巴细胞增殖，显著抑制小鼠脾脏B淋巴细胞增殖。P2和P4样品效果强于其它降解产品和原料。通过测定小鼠游泳和爬杆时间考察了三种降解多糖P1、P2、P4和原料多糖的耐疲劳作用。研究表明：坛紫菜多糖降解产品耐疲劳作用要优于原料多糖P。P1、P2和P4通过提高小鼠肝糖原储备从而达到显著延长小鼠爬杆时间和负重游泳时间的功效。通过测定D. melanogaster果蝇寿命、热耐受时间和性活力考察了三种降解多糖P1、P2、P4和原料多糖对寿命及生命活力的影响。研究表明：分子量对坛紫菜多糖对果蝇的寿命和生命活力有很大影响。降解使坛紫菜原料多糖P对果蝇的延长寿命和提高生命活力作用得到加强。在果蝇正常代谢状态下，降解产品中分子量较大的P1和P2作用更显著，而在热应激状态下，降解产品中分子量较小的P4作用更突出。采用小鼠侧脑室注射Aβ1-40致痴呆模型考察了样品P1改善认知功能的作用。研究表明：P1通过降低皮层和海马组织乙酰胆碱酯酶活性，显著提高乙酰胆碱转移酶的活性，有效改善痴呆小鼠的认知能力，使之水迷宫游泳时间缩短，使避暗潜伏期延长。为探讨P1样品改善小鼠认知功能的作用机制，本文采用Aβ25-35损伤神经母细胞瘤株SH-SY5Y模型对P1样品的神经细胞的保护作用进行了研究。结果显示低浓度下P1对该损伤模型具有显著保护作用，高浓度下表现出显著的抑制作用。本文的研究表明坛紫菜多糖在降解之后生物活性得到显著改善。分子量对坛紫菜多糖活性影响很大。总的看来，在体外实验中，分子量越低其体外抗氧化活性和免疫调节作用越显著，但是，在体内实验中，降解产品中分子量最大的P1样品能更有效地改善小鼠疲劳程度、延长果蝇的寿命及热耐受时间，P1样品还能显著改善痴呆小鼠记忆功能。不同分子量坛紫菜多糖体内和体外生物活性的这种差异还需要进行深入研究。
其他摘要	Porphyra haitanensis, distributes naturally in intertidal zone of Fujian，Guangdong and Zhejiang provinces coast areas. Porphyra is not only an important economic alga, but also has been used traditionally to treat nephritic and urinary diseases etc. The previous work carried out in our lab showed that the water-soluble polysaccharide from Porphyra haitanensis (porphyran) has a favorable effect on antiaging. Molecular weight is reported to be an important factor to the bioactivity of polysaccharide. In this dissertation, studies were concentrated on degradation of seaweed polysaccharide, and its influences on antiaging activities of different molecular weight porphyran. Porphyran (P) was degraded by ascorbate and hydrogen peroxide, imitated the scissions of polysaccharides undergo in the walls of living plant cells. The reaction is mainly affected by the ratios and concentrations of the two reagents. Different molecular weight porphyrans in terms of P1, P2, P3, P4 and P5 were achieved by the degradation method, and their molecular size are 50, 30, 13, 8.2, 2.7 kD, respectively. P1, P2 and P3 are coincident with P in infrared absorptions which indicated that the structural units composing the polysaccharide were not modified in the degradation. However, carboxylic absorption was observed in P4 and P5. The five porphyrans were investigated about their effect on eliminating free radical, T/B-cell proliferation, antifatigue, prolonging lifespan and anti-Alzheimer disease to examine the influence of molecular weight on antiaging effect of porphyrans. The antioxidant activities of five degraded porphyrans and natural porphyran in vitro were investigated by chemical spectrometric methods. The results proved that they have different antioxidant activity. Degraded products are less effective on scavenging superoxide anion than natural porphyran and almost lose the chelating effect. Degraded products are similar with natural porphyran on scavenging hydroxyl radical. But they are more effective on scavenging 1, 1-diphenyl-2-picrylhydrazyl (DPPH•) radicals and reducing power and the effects are increased with decreasing the molecular weight. Among them, P4 is the most effective on scavenging 1, 1-diphenyl-2-picrylhydrazyl (DPPH•) radicals and P5 possesses the most pronounced reducing power. The immunoregulatory effects on T/B-cell proliferation of five degraded products and natural porphyrans proved that they can evidently facilitate T-cell proliferation and inhibit B-cell proliferation. The effects of P2 and P4 activated stronger than other products and P. The antifatigue effects of P1, P2, P4 and P were evaluated on mice. Degraded products were more effective than P. P1, P2 and P4 can improve the content of liver glycogen and prolong the time to fatigue. The effects of P1, P2, P4 and P on the lifespan and vitality were evaluated in Drosophila melanogaster. Molecular weights influence the effect of porphyran on lifespan and vitality favorably. It seems that P1 and P2 are more effective in the normal metabolism; they had significant prolonging effects on lifespans of both genders and vitality than P. And in the heat stress station, P4 treatment showed pronouncedly longer survival time. The effects of P1 on Aβ1-40 induced cognitive deficits were evaluated in mice. P1 treatment significantly ameliorated the cognitive deficits; moreover, the choline acetyltransferas (ChAT) was significantly higher in P1 supplement groups than in the only Aβ-injection groups. Aβ toxicity is viewed as a pathogeny of AD. Thus the effect of P1 on neurotoxicty induced by aged Aβ25-35 was evaluated. In SHSY-5Y cells, treatment with 20 μM of aged Aβ25-35 resulted in a significant inhibition of MTT reduction. Incubation with the mixture of Aβ25-35 and 10 mM P1 remarkably attenuated Aβ-induced inhibition of MTT reduction. However, the toxicity effect of Aβ25-35 was significantly reinforced when the concentration of P1 was increased to 80 μM. Consequently, molecular weight affects the bioactivities significantly. In vitro, lower molecular weight polysaccharides are more effective in antioxidant and immunoregulaory effect. However, in vivo, P1 treatment is more effective in antifatigue, prolonging lifespan, improving vitality and ameliorated the cognitive deficits. The difference of activities in vitro and in vivo needs further research.
页数	107
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/707
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	赵婷婷. 不同分子量坛紫菜多糖的制备及其抗衰老活性研究[D]. 海洋研究所. 中国科学院海洋研究所,2007.

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