Study On The Extraction Of Thymic Polypeptide By Ultrahigh Pressure

Thymic polypeptide (TP) is a polypeptide with bioactivity. It is produced bythymus, one of the central immune organs. It relates to the development anddifferentiation of immune cells. The major function of TP is to promotelymphocytopoiesis and regulate cellular immunity for body. TP is animmunoregulator that has therapeutic effect on the primary and secondaryimmunodeficiency disease (especially T cell immunodeficiency disease) and thedisease caused by immune maladjustment. It can be used for assisted-therapy forall kinds of infection, tumor and endocrine disturbance and anti-decrepitude. TP isexerting more and more important function as a stronger modifier of biologicalresponse for prevention and treatment of disease in iatrology and veterinary clinic.TP produced an obvious effect for therapy of the severe acute respiratory syndrone(SARS) and thus has attracted more and more attention from people, which haspromoted extensive development and application of TP pharmaceutics.At present the preparation methods of TP include the two methods: synthesisand extraction. In our country, extraction technology is applied widely in thepreparation of TP, and it basically is "freeze thaw extraction" (FTE), whichextraction efficiency is very law. TP is mainly extracted from the thymus of calf orporket. The extracted TP is more expensive because of the limited source of rawmaterials. Thus, it is urgent to develop a technology that could increase yield ofunit thymus and extraction efficiency.The ultra high pressure (UHP) technology was originally applied in theproduction of chinaware, steel and super alloy to manufacture reamer of high-speedhard alloy. Presently the UHP technology mainly is used for detectors to controlquality, standardization equipments, the technology of chemical processing, theequipments of scientific research, food processing, the synthesis of nanometermaterials, geological studies and so on. We have first applied the UHP technologyin the extraction of effective components in biologic materials,and procuredfamous results in the extraction of effective components in Chinese traditionalmedicine, thereupon initiated the ultra high pressure extraction (UHPE) technology.There have many advantages in extracting the effective ingredients from crudeherbs with the help of HHP: (1) More kinds of solvent can be used. We can selectappropriate solvents, such as water, lipophililic and hydrophilic organic solvent etc,according to the property of extract. (2) HHP processing is operated at roomtemperature without any heating process such as leaching at high temperature,distillation and so on, so some heat-sensitive effective ingredients of herbs will notlose their biologic activity. (3) Extraction time is very short, and there needs only afew minutes in one extracting course with the help of HHP. (4) The operationparameters of high-pressure equipment are easy to adjust and control. There needsonly one equipment to extract many kinds of effective ingredients from raw herbswith different solvents. (5) Economization of energy. There only have little energytransform and energy exchange with outside during the course of duration anddecompression, and almost no energy is consumed. (6) HHP processing is operatedin an airtight environment, so the solvent can't vaporize to the surroundings.Moreover, there have no wastewater and exhaust gas. So it accords with the requestof the environmental protection.In this study, the UHPE technology was applied in the extraction of TP fromcalf thymus. In order to seek a method, which will give higher extraction efficiency,extraction yield and bioactivity of TP than FTE method, following key technicalproblems are studied:(1) The optimum extraction conditions of TP by UHPE method are: extractionpressure is 350 MPa;extraction time is 1 min;liquid/solid ratio is 3;the pH ofhomogenate is 3.5, which were determined by regression orthogonal design method.Under the optimum extraction conditions, three parallel extraction experimentsgave (6.14±0.12) mg/g of the yield of TP. The E-rosette assay shows that thebioactivity of the TP extracted by UHPE is eligible.(2) In order to compare the results of UHPE with FTE methods, we performedall experiments using calf thymus from the same batch, and the technology of FTEmethod is exactly the same as that given in the literature. The experimental resultsshow that: the two methods are similar in the extraction yield and bioactivity of TP;the UHPE method is excelled than the FTE method in extraction efficiency andtechnology.Through the comparison of UHPE with FTE methods, we think that from theviewpoints of the extraction efficiency and technology UHPE is more effectivethan FTE, and it is a bran-new extraction method of proteins. Some researches arepreliminarily studied in this paper, and they must be further perfected and improvedin the future.