海带活性碘的精制及其对小鼠补碘功能的研究

【作者】 唐晓玲；

【导师】 迟玉森；

【作者基本信息】 山东师范大学 ， 动物学， 2001， 硕士

【摘要】 碘是一种人体必需的、对人类健康至关重要的必需微量元素，它是合成甲状腺激素的原料，因而具有重要的生理意义。缺碘则会给机体带来一系列的危害，严重的甚至会影响智力的发育。目前，全世界缺碘人群达12亿，遍及118个国家，我国有4.5亿之多。而现行的补碘措施以无机碘剂为主，由于无机碘本身易于挥发损失等缺点而具有一定的局限性，使得补碘难以准确到位。因此，开发高效、稳定、安全的新型补碘物质，实现科学补碘，成为当今生命科学研究的热点之一。本文以含碘量最为丰富的食品——海带作为实验材料，从中提取氨基酸态的有机碘——生物活性碘（DIT）并加以精制，确定了最佳的提取、精制工艺，建立了生物活性碘的测定方法，并且对海带活性碘的动物补碘功能研究进行了初步的探索。 1.生物活性碘的测定方法的建立。 目前关于碘的测定方法有很多报道，但所测定的都是无机态的碘，对有机态存在的生物活性碘的测定方法尚未见报道。研究发现，海带中的总碘包括无机碘和有机碘两类。采用消化的方法，可以将溶液中各种形态的碘全部转化为碘离子的形式，以砷-铈接触法可以测定出海带提取液中总碘的含量，从而为海带生物活性碘的提取精制提供参考。研究中还发现，标准品DIT在221nm波长处有最大吸收，而且吸光度值与溶液浓度之间存在着线性关系，因而建立了紫外分光光度法直接测定DIT的含量。 2.生物活性碘的提取、精制研究 海稀活性碘的粉俐汉其对小甩孙碘功旭的研咒 考察了不同的预处理方式、不同的时间、不同的提取温度等条件对海带中生物活性碘提取效果的影响，从而确定了最佳的提取方法：原料清洗、晾干后，120OC，0．IMPa高温高压下处理 30分钟，然后于 50C无碘水中浸提12个小时。在此基础上又研究了精制的方法。通过过滤。膜超滤、真空浓缩、离于交换层析、活性炭（粒状）吸附层析等方法逐步除去蛋白质、多糖、无机离子等杂质。研究发现：粒状活性炭对海带提取液中生物活性碘具有良好的吸附和脱附性能，吸附率和脱附率可达到 90％以上，适合工业生产使用。将 pH为 7的溶液以 2 ml／min的速度上柱，吸附效果好；吸附后立即洗脱，选择2＊。1几氨水作洗脱剂，以2 ml／min的速度洗脱，脱附率可达 95％以上。将洗脱液排氨浓缩后，喷雾干燥得到浅黄色粉木，其中DIT含量达到5060儿 得率为24“ 3．海带活性腆对小鼠的补碘功能研究。 本文研究了海带中生物活性碘DIT的热稳定性，并与无机碘剂KI的稳定性进行了比较，结果表明，270aC下加热处理2小时，DIT依然稳定地存在，而 厂几乎全部挥发。另外通过建立缺碘动物模型，研究了生物活性碘的补碘功效。结果表明，从海带中提取的生物活性碘与标准品DIT（Sigmet公司进口）的补碘效果无显著差异，但均优于无机碘KI的补碘效果。 以上结果说明，海带生物活性腆——是一种优良的补碘剂。如果能够开发应用，必将具有广阔的前景，对于实现科学补碘将具有重要意义。更多还原

【Abstract】 Iodine is a kind of trace elements necessary to people as far as thehealth is concerned. It has greatly physiological significance because it is oneof the components in thyroxin. The lack of iodine will bring a series ofhazards to the body, even influence the deve1opment of mentality .The 1ackof iodine occurs in 1 l8 countries. There are l20 million people in the worldand about 45million in our country who have been bothered by the lack ofiodine. While the current remedies complementing iodine are main1ycomposed of inorganic iodine which has some limitation to a certain extent.It is one of the hottest points to find highly efficient, safe, stable, new iodinepreparations and to reality the ideal of complementing iodine scientitIcally.The bio-active iodine combined with arnino acid --3,5diiodotrysine (DIT )was extracted from the kelp which has the largest content of iodine. Thetechnology of extraction and purification was confirmed. The method tomeasure bio-active iodine was set up and the pilot study of itscomplementing effect on mice which were deficient of iodine was done.l .The method to measure bio-active iodine was set up.A lot of methods to measure inorganic iodine have been reported whilethe measurement on organic iodine hasn’t been seen. There are differentforms of iodine in ke1p including inognic iodine and organic iodine Thepowerful oxidant can transform all kinds of iodine to I- that catalyzes thereaction between Ce4+ afld As3+, thu$the tOtal content of iodine can bemeasured, which makes a basis for the stlldies on technology of extractionand purification.It was found that there was the maximal absorption at the wavelength of22lnm for the normal DIT A Iine connected the optical density and theconcentration of solution. So the method depending on the ultravioletspectrophotometer was set uP to measure the content of DIT directly.2. The extraction and purification of bio-active iodine were studied.The conditions influencing extracting of bio-active iodine such asdifferent methods of pre-treatment, time, temperature and so on werediscussed. Then the best conditions of extraction were confirmed. The kelpwas cleaned by water, dried in the air,under the conditions of 120oCo. lMPa for 30 minutes, soaked in the water without iodine for l2 hours at50’C. Then the methods to purify were studied. Such impurity as protein,amylase, inorganic ion was separated through t1ltration, ultratiltration,vacuum concentration and ion exchange as well. Then the method ofabsorbing and separating DIT with active carbon was stll4ied... Theexperiment resu1ts showed that the grain active carbon was suitable forseparation and purification of DIT industrially with the high percent ofabsorPtion and elution both above 90%. The so1ution, pH=7, was added tothe active carbon column at the speed of 2ml/min, which had a good effect ofabsorption. The DIT absorbed by active carbon was eluted by 2mo1/Larnmonia watef, at the speed of 2ml/min, with the percent of ellltion abOve95%. Then the eluted solution was concentrated and the ammonia wasexcluded at the same time. After drying with spraying, the light yellowpowder product was reeeived. The content of DIT got to 50~60% and theDIT yield was 2~4%.3. The complementing effect of bio-active iodine on mice was studied.The thermal stability of DIT was studied and was compared with that ofthe inorganic iodine KI. The results showed that DIT was still stable whilealmost all I- volatilized under the same treatment at 270OC for 2 hours. Onthe other hand, an iodine-deficient model was established. Bio-active iodineextracted from kelp, normal DIT imported from Sigma Company and KI allcould supply iodine to animaI. But the effect of bio-active iodine extf8ctedfrom kelp was identified with the normal DIT while superior to the inorganicKI.All the results suggested that DIT extracted from kelp is an excellentremedy to complement iodine. Theret更多还原