WO2001040315A1

WO2001040315A1 - The alginate having low molecular weight, methods of manufacturing it and its use

Info

Publication number: WO2001040315A1
Application number: PCT/CN1999/000202
Authority: WO
Inventors: Chuanxing Yu
Original assignee: Dalian Yaweite Biology Engineering Co., Ltd.
Priority date: 1999-11-30
Filing date: 1999-11-30
Publication date: 2001-06-07
Also published as: WO2001040315A8; WO2001040315A9; CA2430277A1; AU1502700A

Abstract

The alginic acid or the salts thereof having average molecular weight of between about 5,000 -20,000 daltons and exhibiting intrinsic viscosity of between 1 - 20 measured by the Ubbelohde viscometer are provided. Most of the alginates have molecular weight of between 1,000 - 30,000 daltons. They are prepared form a high molecular weight alginic acid by means of decomposition, ultrafiltration and nanofiltration membran. they are of uses for prevention and treatment of hypertension, primary hyperaldosteronism and for reducing blood sugar.

Description

Low-molecular-weight alginate, and preparation method and application thereof

The present invention relates to a low molecular weight alginate. More specifically, the present invention relates to an alginate with alginic acid as a raw material and an average molecular weight obtained by a degradation method of about 5000-20,000 Daltons. The viscosity characteristic viscosity number is between 1 and 20, and the molecular weight of most of the alginate molecules is between 1,000 and 30,000 Daltons. The invention also relates to a method for preparing such a low molecular weight alginate and its use in the prevention and treatment of high blood pressure and primary aldosterone (ALD) and blood glucose reduction.

Background technique

Natural alginic acid is a very common substance that can be extracted from marine plants such as kelp, kelp, brown algae, and macroalgae, and has a wide range of uses. Natural alginic acid and its derivatives are used to lower blood pressure and prevent hypertension. Drugs for this disease have long been documented in the literature.

Kelp is a relatively abundant resource in the ocean and is widely cultivated on the coastlines in many places. In the coastal areas of China, kelp roots are used to reduce the symptoms of hypertension. Ingestion of 12 grams per day has a certain effect on primary or secondary primary hypertension. People extract alginic acid or its salts from plants such as kelp and use it in various applications. For example, adults taking more than 20 grams of sodium alginate daily have a temporary hypotensive effect. Some people have also used potassium alginate in SHR spontaneously hypertensive rat experiments, and found that animal experiments are effective, but for humans, hypertension patients with large molecular weight potassium alginate have no significant effect. However, taking alginate with too small molecular weight does not have a long-term hypotensive effect. For example, Japanese Patent Application Laid-Open No. 6-237783 discloses an alginic acid prepared by using alginic acid as a raw material for preventing hypertension and having health effects. Oligosaccharides and their preparation methods, they use degrading enzymes that can degrade polysaccharides to prepare potassium alginate belonging to oligosaccharides with a degree of polymerization of 2-5 from natural alginic acid, but the purpose of the product is only to prevent (inhibit) hypertension There is no treatment effect on hypertension.

CNI097307 discloses a seaweed slimming agent, which is obtained by the following methods: submerging and immersing a commercially available medicinal alginic acid in water to make it swell, and then adding 6-7N hydrochloric acid to degrade alginic acid into an oligomer. After deacidification, a saturated ethanol solution of potassium hydroxide was added to convert it into potassium alginate oligosaccharide. Finally, the pH was stabilized at 8, dried, and pulverized to obtain a powdered brown alga slimming agent. However, the molecular weight of the product and the effect of lowering blood pressure are not specifically described in the patent, nor is the effect of treating hypertension and hyperaldosteronism emphasized.

SU1821470 discloses a method for extracting glycans from aquatic plants, which comprises extracting from pretreated aquatic plants in an alkaline solution at an elevated temperature, adding hydrochloric acid or sulfuric acid, and separating the alginate Hydrolyzed at 80-100 ° C and PH = 0-1, cooled, neutralized with caustic soda, purified the mixture, depolymerized alginate was precipitated, and the hydrolysate was dried to a viscosity of 1.5-4.0 cPs. There is no mention of the use of the product in the treatment of hypertension.

WO9320826 A1 discloses an alginate-based pharmaceutical composition for preventing and treating gastrointestinal disorders.

US5460957 discloses a new alginate oligosaccharide compound containing calcium and potassium ions, but not sodium, It is used as a hypotensive additive in foods. The alginate oligosaccharide (I) is obtained by (1) treating sodium or potassium alginate with a glycanase (II), and then (2) replacing sodium (or sodium and sodium with calcium or potassium ions). Potassium) ions, and / or calcium and other potassium ions. The product of this patent has a degree of polymerization of 2 to 5 and a low molecular weight.

KR9200242 discloses a method for preparing low molecular weight alginate, which only uses ultrasonic treatment to decompose the polymer main chain, but the molecular weight of the product is generally above 35,000, and repeated ultrasonic treatment can only reach 20,000 or above 20,000. The role of preventing and treating hypertension is not indicated in the patent.

KR9105768 discloses a method for extracting sodium alginate from brown algae. The molecular weight of the product is between 60,000-300,000.

US5283076 discloses a food or beverage containing sodium alginate having a molecular weight of 10,000 to 150,000, which is used to prevent obesity and diabetes.

JP3273002 discloses a decomposition substance of alginic acid, which has a molecular weight of 1000-1500 and is used as a stabilizer for food or medicine.

US4104460 discloses a method for extracting alginic acid from seaweed, which includes adding a hydrogen peroxide compound to alginic acid and then treating it with a base such as sodium carbonate, ammonium carbonate, sodium hydroxide, etc., but it is not mentioned in the literature as a drug the use of.

The alginate derivatives obtained in the prior art can only work within a short period of time, mainly suppressing the increase in blood pressure, but generally have no therapeutic effect.

Summary of the Invention

The object of the present invention is to provide an alginic acid (salt) derivative, which is required to prevent and treat hypertension and aldosteronism with a prominent effect and a long duration of action, and at the same time a blood glucose lowering effect.

After years of research, the inventors discovered that natural alginic acid (salt) is degraded to a certain degree by oxidation, enzymatic methods, etc., that is, the average molecular weight is within a certain specific range. At this time, alginic acid and its salts are effective in treating hypertension. And aldosteronism are very effective and can lower blood sugar.

The research work of the present invention is divided into three stages. The average molecular weight of the alginate initially prepared is 6.8 × 10 ^4. The molecular weight of most of the alginate molecules is between 2000 and 100,000, and the molecular weight above 50,000 is separated. After being dropped, the remainder was clinically observed by Xiyuan Hospital of China Academy of Traditional Chinese Medicine. Taking 5-8 grams daily has a significant effect on patients with essential hypertension, with a total effective rate of 83.3%. We have examined the range of molecular weight distribution. Using alginate with a molecular weight greater than 30,000 and a molecular weight distribution mainly in the range of 30,000-100,000 for clinical observation of hypertension patients, no significant hypotensive effect was found. In the second stage, we prepared a low molecular weight alginate with an average molecular weight of 3.5 × 10 ⁴ and the molecular weight of most of the alginate molecules was between 2,000 and 58,000. The total effective rate of patients with essential hypertension reached 85%. In the third stage, we prepared a lower molecular weight alginate with an average molecular weight between 5000-20,000, preferably between 7000-12,000 and particularly more preferably 6000-10000, and most preferably 7000-9000 between. Preferably, the molecular weight of most of the alginate molecules is between 1,000 and 30,000 and preferably between 1,600 and 20,000, especially between 1600 and 12,000, and especially between 1,600 and 10,000 and most preferably between 1800 and 10,000. The albednate product has an inherent viscosity number between 1 and 20 and preferably between 3 and 14. In particular, when the alginate has an average molecular weight between 6000-9000 and the molecular weight of most of the alginate molecules is in the range of 1600-10,000, a daily dosage of 0.5-3 g of the alginate versus the original The total effective rate of patients with essential hypertension reached more than 88%, and after taking it continuously for a week, the patient's blood pressure stabilized at a normal level within 2 to 3 days. Therefore, the present invention was completed in the third stage.

The invention provides a low-molecular-weight alginate. More specifically, the invention provides alginic acid as a raw material, and an average molecular weight obtained by a combination of a degradation method and a membrane separation technology is about 5000-20,000, and preferably 7000. Alginates between -12,000 and particularly preferably between 7500 and 8500. Preferably, the molecular weight of most of the alginate molecules is between 1,000 and 30,000 and more preferably between 1,600 and 20,000 and most preferably between 1,600 and 10,000. The Uighur viscosity intrinsic viscosity number of the alginate product is between 1 and 20, and the salt-forming cation of the alginate is a pharmaceutically acceptable cation or trivalent chromium ion.

The present invention also provides a method for preparing such a low-molecular-weight alginate and its use in preventing and treating hypertension and primary aldosteronism and reducing blood sugar.

In the above preparation method, the degradation step includes a physical method, a photochemical method, an immobilized enzyme method, or a chemical method.

Physical methods include ultrasonic treatment or high-speed shear processing; photochemical methods use light radiation and catalysis for processing; and chemical methods use strong acids, strong bases, and inorganic or organic oxidants.

For oxidative degradation methods, oxidants are required, and these oxidants include organic and inorganic oxidants. It includes hydrogen peroxide, peracetic acid, potassium peroxide, potassium percarbonate, potassium (sodium) perborate, potassium permanganate, ammonium persulfate, double salts of potassium persulfate, sodium chlorite, potassium chlorite, and many more.

After alginic acid degradation, ultrafiltration membrane and nanofiltration membrane retention technology are needed to obtain products with the desired molecular weight range. The present invention uses DHFM series ZBS Type 1 and ZBS Type 3 hollow fiber ultrafiltration membranes produced by the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences to cut molecular weights of 10,000 and 30,000, respectively, and cut off alginates with molecular weights greater than 10,000 or 30,000, respectively. Then, using the NF4040 nano-filter membrane, which is produced by Dalian Institute of Chemical Physics Membrane Engineering Center, is a brand name that can filter out alginates with a molecular weight of less than 1000 or 1200 (slightly pressurized).

Here, the "most part" in the phrase "the molecular weight of most of the alginic acid (salt) molecules" is explained: Since the pore sizes of the ultrafiltration membrane and the nanofiltration membrane are not absolutely uniform, there are a few slightly larger ones. Or slightly smaller filter pores, and the pore size will change under different pressures, so the molecular weight cut-off can be modified with "mostly". For example, when using a nanofiltration membrane to filter, the original design trapped 1,000 molecules, but because the filter pores are not strictly uniform and the filter pores change with pressure, a small number of molecules with a molecular weight slightly higher than 1000 (such as the molecular weight of 1200) will also Missed.

The invention provides a method for preparing a low-molecular-weight alginate, which comprises: (1) a degradation step: degrading a high-molecular-weight alginic acid raw material to an average molecular weight of more than 20,000 to about 80,000 Daltons, adding an alkali solution to dissolve it (2) Use ultrafiltration method to cut off molecules with a molecular weight above 30,000 Daltons, leaving the molecules behind Alginate molecules with an amount of less than 30,000 Daltons, and (3) using a nanofiltration membrane to cut off alginate molecules with a molecular weight of less than 1,000 Daltons, resulting in an average molecular weight between 5000 and 20000 Daltons and a large The molecular weight of some of the alginate molecules is in the range of 1,000 to 30,000 Daltons, and finally dried.

A method for preparing a low-molecular-weight alginate, which comprises: (1) a degradation step: degrading a high-molecular-weight alginic acid raw material to a molecular weight of more than 20,000 to 80,000 Daltons; (2) preparing the degradation product by treating it with an alkali Soluble salts, (3) add water or a water-containing medium under stirring, and then add an oxidant to further degrade the product into a lower molecular weight alginate, (4) use ultrafiltration to cut off molecules with a molecular weight above 30,000 Daltons Leaving alginate molecules with a molecular weight of less than 30,000 Daltons, and (5) using a nanofiltration membrane to cut off alginate molecules with a molecular weight of less than 1000 Daltons to obtain an average molecular weight between 5000 and 20000 Daltons and The molecular weight of most of the alginate molecules is in the range of 1000 to 30,000 Daltons, and finally dried.

A method for preparing low-molecular-weight alginic acid, comprising: (1) a degradation step: degrading a high-molecular-weight alginic acid raw material to an average molecular weight of more than 10,000 to about 70,000 Daltons by adding an alkali solution to dissolve it; (2) utilizing The ultrafiltration method cuts off molecules with a molecular weight of more than 10,000 Daltons, leaving alginic acid molecules with a molecular weight of less than 10,000 Daltons, and (3) uses a nanofiltration membrane to cut off alginic acid molecules with a molecular weight of less than 1200 Daltons, The average molecular weight is between 5000 and 8000 Daltons and the molecular weight of most of the alginate molecules is in the range of 1200 to 10,000 Daltons, and finally dried.

A method for preparing a low-molecular-weight alginate, which comprises: (1) a degradation step: degrading a high-molecular-weight alginic acid raw material to a molecular weight of more than 10,000 to 70,000 Daltons; (2) preparing the degradation product by treating it with an alkali Soluble salts, (3) add water or an aqueous medium under stirring, and then add an oxidant to further degrade the product to a lower molecular weight alginate, (4) use ultrafiltration to cut off molecules with a molecular weight above 10,000 Daltons Leaving alginate molecules with a molecular weight of less than 10,000 Daltons, and (5) using a nanofiltration membrane to cut off alginate molecules with a molecular weight of less than 1200 Daltons to obtain an average molecular weight between 5000 and 7000 Daltons and The molecular weight of most of the alginate molecules is in the range of 1200-10,000 Daltons, and finally dried.

The degradation steps in these preparation methods include methods such as physical degradation, photochemical degradation and chemical degradation, and immobilized enzymes.

Physical methods include ultrasonic treatment and high-speed shearing; photochemical methods use light radiation and catalytic treatment; and chemical methods use strong acids, strong bases, and inorganic or organic oxidants for processing.

The small molecule alginate that can be absorbed into the blood vessels through the intestinal mucosa is the main functional component of alginate to reduce blood pressure and is also the main component effective for primary aldosteronism. Alginate with a molecular weight greater than 12,000 passes through the intestinal mucosa And the amount absorbed by the intestinal tract is reduced. As the molecular weight increases, the alginate absorbed by the intestinal mucosa becomes less and less. Only the alginate containing potassium has a certain effect. Alginate regulates blood pressure only because of the combination of alginic acid and sodium ions in the intestinal tract, and regulates blood pressure through sodium-potassium ion exchange. In other words, in order to play a greater role, alginate must be absorbed by the intestine, so the molecular weight is the key. It is worth mentioning that the molecular weight of alginate is too small (for example, less than 900), and although it is easy to absorb, it can show a hypotensive effect, but the maintenance time is short. Alginate containing chromium has the effect of reducing blood sugar. The content of chromium in alginate generally accounts for 0.01% to 0.05% of the total weight of alginate. Taking 6-8g of alginate containing chromium daily has a significant reduction Sugar effect.

The alginic acid used in the present invention is extracted from marine plants, especially from kelp, kombu, and brown algae, where kelp is a rich and cheap resource. In order to obtain the alginate having a specific average molecular weight according to the present invention, we use commercially available high molecular weight alginic acid or a salt thereof as a raw material, or use alginic acid or a salt thereof extracted according to an ordinary method as a raw material Or the average molecular weight of its salt is generally 30,000-300,000. There are no restrictions on the method for preparing such high molecular weight alginic acid or its salt from marine plants, as long as the molecular weight and molecular weight distribution are within the ranges specified above.

The salt of the present invention may be any pharmaceutically acceptable salt, that is, a pharmaceutically acceptable salt. Salt-forming cations include, for example, cations of alkali metals, alkaline earth metals, iron, zinc, chromium (111), manganese, and the like, and ammonium ions. Of these, soluble alginates are preferred, and potassium salts are most preferred. In this article, "alginic acid" and "alginic acid" have the same meaning, as do "alginate" and "alginate".

The "molecular weight" used here is determined by column chromatography: The instruments used are HL-2 type constant flow pumps produced by Shanghai Huxi Instrument Factory and BSZ-100 automatic partial collectors, and also produced by Shanghai Analytical Instrument Factory 222 spectrophotometer; Because alginic acid or its salt is a polysaccharide, Dextran with different molecular weights is used as a control. Dextran T4-6 has an average molecular weight of 5,000, Dextran T8-12 has an average molecular weight of 10200, and Dextran T60. -90 has an average molecular weight of 68300, Dextran T100 has an average molecular weight of 100,000, and Dextran 200-300 has an average molecular weight of 266,000. This series of Dextran (trademark) are products of the Swedish Pharmacia company and are provided by Farco Chemical Supplies of Hong Kong; The column chromatography packing was Sephacryls-300; the measurement conditions: a total of 50ml, the eluent was a 0.1 molar concentration sodium chloride solution, the flow rate was 1ml / min, and the collection was: 1ml / tube; detection method: take about 10mg of the sample, add 1ml of water Dissolve it, add resorcinol hydrochloride solution, heat and boil, it will show reddish purple, this product is mannuronic acid and guluronic acid Heteropolymer bound potassium salt can be generated with a phloroglucinol compound of a purple solution of hydrochloric acid; then detected by means of a spectrophotometer, Shimadzu spectrophotometer or an alginate in the absorbance at 230nm.

Precisely weigh 5 mg each of Dextran T4-6, T8-12, T60-90, T100, T200-300, dissolve in 0.5ml eluent, and load them on the column respectively. Under this condition, the low molecular weight alginate is accurately weighed. The amount was 5 mg, dissolved in 0.5 ml of eluent, and eluted on the column under the same conditions as the working curve of the reference preparation. The elution working curve of the Dextran control substance and the elution working curve of the sample of the present invention were plotted, and the average molecular weight of the low molecular weight alginate was determined by comparison. It must be noted that the insoluble alginate is converted to a soluble salt (such as sodium or potassium) by ion exchange before measuring its molecular weight. For example, calcium alginate is first converted to alginic acid precipitate by adding hydrochloric acid, and then using hydrogen Treatment with aqueous sodium oxide solution converts to water-soluble sodium alginate.

The Uighur viscosity intrinsic viscosity number is determined in accordance with the Chinese Pharmacopoeia 1995 edition, Appendix VI G: Viscosity Test Method, with 0.2 ^% seaweed salt concentration.

Overview of the drawings

1 is an infrared absorption spectrum of a low-molecular-weight potassium alginate of Example 1; Figure 2 is an infrared absorption spectrum of a high molecular weight alginic acid raw material;

3 is a 'H-NMR spectrum of the low-molecular potassium alginate of Example 1;

Fig. 4 is a 'H-NMR spectrum of a high molecular weight alginic acid raw material.

Best Mode of the Invention

Example 1: Ultrasonic degradation method

Weigh 100g of alginic acid (a nationally approved medicinal alginic acid produced by the Dalian Algae Industry Company of China) with an average molecular weight of 200,000 and a molecular weight distribution range of approximately 35,000-300,000. Add water to the alginic acid so that the alginic acid accounts for about 10% of the total, and stir. US Sonic & Materials Model 1500, total power 1500W, working frequency 20KHz, ultrasonic treatment of alginic acid suspension for 2 hours, adding potassium hydroxide solution while ultrasonic treatment to keep the pH between 5-9, average Seaweed salt solution with a molecular weight of 35,000. Then, a DHFM series ZBS 3 type hollow fiber ultrafiltration membrane (using 0.15Mpa pressure) produced by the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences was used to cut the molecular weight of 30,000 and cut off the potassium alginate with a molecular weight of more than 30,000 to obtain potassium alginate with a molecular weight of less than 30,000. The solution. Then, the NF4040 nanofiltration membrane (pressurized at 0.15 MPa) produced by Dalian Institute of Chemical Physics and its membrane engineering center was used for dehydration and filtration to remove alginates with a molecular weight of less than 1200. After two filtrations, the molecular weight was obtained. Products with a distribution range of 1,200-30,000. A double molecular weight of 95% ethanol was added to the product to precipitate a low molecular weight potassium alginate. The precipitate was dried and its average molecular weight was 16,000 as determined by column chromatography.

The cut off potassium alginate having a molecular weight of more than 30,000 is used as a part of the raw material, and a certain amount of original commercially available alginate raw material is replenished, and the above operation is repeated.

The low-molecular-weight algal potassium of this example was subjected to infrared analysis and 'H-NM spectrum test, and compared with raw material alginic acid. The infrared spectra of FIG. 1 and FIG. 2 were compared, and the ¹ H-NMR spectra of FIG. 3 and FIG. 4 were compared. The results show that the molecular structure has not changed substantially before and after degradation.

Example 2: Hydrogen peroxide degradation

The first stage: Weigh 500g of alginic acid (Nationally approved medicinal grade alginic acid produced by Dalian Algae Industry Company, China). Add alginic acid to distilled water, and stir evenly so that the alginic acid accounts for 9% of the total water. Heat to 40 ° C (reaction temperature). Add hydrogen peroxide (containing H ₂ 0 ₂ 30%) dropwise while stirring to make the system The final hydrogen peroxide concentration (referred to as the final H ₂ 0 ₂ concentration) is 1% of the total weight. The reaction is carried out for 2 hours under stirring, and the unreacted hydrogen peroxide is removed by decomposition after heating up to 80 ° C, and then under stirring Add 30% potassium hydroxide solution to alginic acid treated with hydrogen peroxide dropwise, and add an appropriate amount of distilled water to fully dissolve the product, and finally keep the pH of the system between 6-7. At this time, the average molecular weight of the product is 65000. The intrinsic viscosity numbers of the products are shown in Table 1.

Second stage: Use DHFM series ZBS type 1 hollow fiber ultrafiltration membrane (using 0.15Mpa pressure) to cut molecular weight 10,000, cut off potassium alginate with molecular weight greater than 10,000, and obtain a solution of potassium alginate with molecular weight less than 10,000. Then, using a Bert brand NF4040 type nanofiltration membrane (depressed with a pressure of 101 MPa) to dehydrate and filter out alginates with a molecular weight of less than 1,000. After two filtrations, a product with a molecular weight distribution ranging from 1,000 to 10,000 was obtained. It was then dried and its average molecular weight was 7,500 as measured by column chromatography. The cut off potassium alginate with a molecular weight greater than 10,000 is used as a part of the raw material, and a certain amount of the original commercially-available alginic acid raw material is replenished, and the above operations are repeated.

Examples 3-10:

The procedure of Example 2 was repeated, except that the reaction temperature and the final hydrogen peroxide concentration are shown in Table 1 below. Table 1: Experimental results

Example 11: Combination of hydrogen peroxide and ultrasound

First, the same operation procedure as in the first stage of Embodiment 2 is performed.

Then the product was ultrasonically treated at 40 ° C for 1 hour (using Sonic & Materials Model 1500, total power 1500W, using working frequency 20KHz), 30% potassium hydroxide solution was added dropwise while ultrasonic treatment, and finally the pH reached After approximately 7.3, the addition of potassium hydroxide solution was stopped.

The DHFM series ZBS type 1 hollow fiber ultrafiltration membrane was used to cut the molecular weight of 10,000 and cut off the potassium alginate with a molecular weight of more than 10,000 to obtain a solution of potassium alginate with a molecular weight of less than 10,000. Then, a bert brand NF4040 nanofiltration membrane was used for dehydration and alginate with a molecular weight of less than 1000. After two filtrations, a product with a molecular weight distribution ranging from 1,000 to 10,000 was obtained. A double volume of 95% ethanol was added to the product to precipitate a low-molecular-weight potassium alginate, and the precipitate was dried. The average molecular weight was 7000 measured by column chromatography, and the intrinsic viscosity was 3.

The cut off potassium alginate with a molecular weight greater than 10,000 is used as a part of the raw material, and a certain amount of the original commercially-available alginic acid raw material is replenished, and the above operations are repeated. Example 12: Potassium peroxide ₂ 0 ₂ ) oxidation method:

Nine experiments were performed in parallel, and 100 g of alginic acid was weighed in each experiment, and 400 ml of distilled water was added to infiltrate it. Three different reaction temperatures were used: 40 ° C, 60 ° C, and 80 ° C. 20% potassium peroxide aqueous solution was added under stirring. For each reaction temperature, three different final K ₂ 0 _{2 were selected.} Concentrations: 2%, 4% and 6%. After potassium peroxide was added, stirring and reaction were continued for 2.5 hours. A colloidal product, namely potassium oligoalginate, was added. Distilled water was added, and the pH was adjusted to 7.0 with a 20% potassium hydroxide aqueous solution, so that the potassium alginate concentration was 0.8%. The molecular weight was 10,000 using a DHFM series ZBS 1 hollow fiber ultrafiltration membrane. And then use the Burt card NF4040 type nanofiltration membrane filters out alginate with a molecular weight of less than 1000 and dehydrates it to concentrate into a 5% slurry. Adds 95% ethanol equivalent to twice its volume to settle and dry to obtain seaweed with an average molecular weight of 8,000. Potassium acid.

The cut off potassium alginate with a molecular weight greater than 10,000 is used as a part of the raw material, and a certain amount of the original commercially-available alginic acid raw material is replenished, and the above operation is repeated.

Experimental results

The average molecular weight of the product obtained by using a reaction temperature of 80 ° C and a concentration of 6% by column chromatography was 6,000.

Example 13: Oxidation method with potassium peroxide

The procedure used was similar to that in Example 12, except that a 20% aqueous solution of potassium peroxide was replaced with a 30% aqueous solution of potassium carbonate.

The intrinsic viscosity of the product was very close to the result of Example 12.

Example 14: Hydrogen fluoride treatment method

Crush 100g of alginic acid and dry it under vacuum, then send it to the reactor, evacuate to 5mmHg, add HF gas to make the pressure in the reactor reach normal pressure, and let alginic acid absorb 32-40% of HF by weight. Stir at 20 ° C for 1 hour. Then HF gas was desorbed from the reactor by using inert gas tetrachloroacetamidine at 80-100 ° C to obtain oligoalginic acid. The desorbed HF gas is recovered and reused.

Neutralize the alginic acid with a 10% potassium hydroxide solution to a pH of about 7.3, add an appropriate amount of water to make a potassium alginate solution, and repeat the ultrafiltration and nanofiltration membrane operations of the previous example using ZBS1 and F4040 nanofiltration membranes Filter out fluorine-containing impurities. It was precipitated with 95% ethanol equivalent to twice the volume of the product, and dried to obtain potassium alginate having an average molecular weight of 7,000.

Example 15: Degradation method of immobilized enzyme

Immobilized enzyme degradation technology can improve the utilization rate of the enzyme. Based on the research results of EMERY, AN (Chem Eng., 71, 1972), it is improved. Porous sodium glass spheres are used, with a capillary pore size of 600-800 angstroms and a ball diameter of 1 mm. The porous sodium glass ball was immersed in a 5% 11 ₄ solution at 45 ° C for 24 hours, and then the titanium tetrachloride not absorbed was washed with distilled water. Then, the porous glass ball soaked with titanium tetrachloride was placed in alginic acid Decomposing enzyme (see Japanese patent Application JP 6-237783) in a 2% concentration solution, soaked at 2 ° C for 18 hours, packed the porous glass spheres soaked with alginate-degrading enzyme into a column chromatography test packing column, and kept at 40-55 ° C. Next, add 0.8% potassium alginate solution to the packed column to maintain pH 7.0-7.3. It takes 6 hours from the time of addition to the flow-out time to obtain a low molecular weight potassium alginate solution with a molecular weight distribution width of 800-35,000.

Example 16: Photochemical degradation method

Titanium oxide powder is adhered to the surface of the clay ball, sintered at 1250 ° C into 2mm diameter titanium oxide balls, mixed with alginic acid containing 25% water, put into a sealed container, and passed in oxygen, using visible light or Ultraviolet light was irradiated for 20 hours to obtain oligomeric alginic acid. 10% potassium hydroxide aqueous solution was added to neutralize it to a pH of about 7.3, and an appropriate amount of water was added to prepare a potassium alginate solution. ZBS1 and NF4040 nanofiltration membranes were used to repeat the ultra-thin Filtration and nanofiltration membrane operations, precipitation with 95% ethanol equivalent to twice the volume of the product, and drying to obtain potassium alginate with an average molecular weight of 7000, titanium oxide pellets can be recycled and reused.

Example 17: Preparation method of low molecular weight calcium alginate

Using a method similar to the previous embodiment, the alginic acid raw material is oxidatively degraded by hydrogen peroxide. The amount of hydrogen peroxide added should be such that hydrogen peroxide accounts for 1% to 3% of the weight of the mixed slurry of alginic acid and water, and the heating temperature is 40%. The reaction was carried out at 80Ό and the oxidation time was 2 hours. 30% sodium hydroxide solution was added to the oxidized alginic acid to convert it into low-molecular-weight sodium alginate. The ultrafiltration and nanofiltration membranes of the previous examples were repeated using ZBS1 and F4040 nanofiltration membranes. This operation yielded sodium alginate having an average molecular weight of 8000. Then, a 5% calcium chloride aqueous solution was added to obtain an insoluble alginic acid precipitate, which was washed with distilled water, and the generated hydrochloric acid was removed to bring the pH close to neutral and dry.

Example 18: Preparation method of chromium-containing alginate-The procedure of Example 17 was repeated, except that the calcium chloride solution was replaced with a trivalent chromium ion solution such as chromium trichloride. Example 19: Preparation method of low molecular weight alginic acid

100 g of the low molecular weight alginate of Example 2 was treated with 10% HC1 to obtain a low molecular weight alginic acid precipitate, washed with distilled water, and then dried.

The pharmaceutical preparation is prepared as follows:

Capsules:

Take an alginate product with a molecular weight of 8000 and fill it into gelatin capsules to make capsules. Each capsule is 0.5 g, and about 4 capsules are taken daily.

The low-molecular-weight alginic acid of Example 19 was used to fill capsules. Each capsule was 0.5 g, and about 4 capsules were taken daily.

Granules:

Fill a plastic pouch with alginate with an average molecular weight of 8000, 1 lg per bag, and take 1 to 2 bags daily. If plastic sachets are filled with alginate with an average molecular weight of 18,000, 2 g per bag, take 1 to 2 bags daily.

tablet: The common medicinal starch sold on the market was mixed with alginate with an average molecular weight of 8000 at a ratio of 1: 3, and the tablets were compressed on a tableting machine to make each tablet weigh 0.7 g and take 4 tablets daily.

Capsules, granules and tablets are recommended after meals.

The effects of alginate in the treatment of hypertension are as follows:

Xiyuan Hospital of China Academy of Traditional Chinese Medicine 30 cases of patients with essential hypertension taking low molecular weight potassium alginate (5,000-30,000), taking 4 to 7 grams per day, has a definite effect on primary hypertension, with a total effective rate of 85 %.

Cardiovascular experts at Dalian Medical University use lower molecular weight potassium alginate (1,000-10,000) to observe nearly 30 patients with hypertension, taking 1 to 4 grams daily, which has a clear effect on patients with essential hypertension. Effective rate is over 88%.

The effects of treating aldosteronism are as follows:

Low molecular weight potassium alginate can treat hyperaldosteronism associated with hypertension.

Ten subjects are now provided. Using radioimmunoassay kits, the plasma aldosterone levels of these ten subjects before and after taking low molecular weight potassium alginate were measured. Ordinary diet, standing blood test. The alginate granules were orally administered in an amount of 6-8 g twice daily, and after 15 consecutive days of administration, the levels of aldosterone in the plasma before and after the administration were measured by radioimmunoassay (RIA).

Table 1: Ortho aldosterone levels

After statistical processing, the plasma aldosterone levels of 10 subjects were calculated. The average ALD level before treatment = 235ng / L, the average ALD level after treatment = 172ng / L, and the average reduction was 63ng / L.

The hypoglycemic effect is as follows:

30 hypertensive patients accompanied by high blood glucose concentration, with an average blood glucose concentration of 7.0mmol / L plasma, taking 6-8 g of chromium-containing alginate daily (the content of chromium is 0.01% of the total alginate weight) After 15 days, the blood glucose level decreased to 4.7mmol / L on average.

Claims

Claim

1. A low-molecular-weight alginic acid or a salt thereof, which is obtained by combining alginic acid as a raw material and a degradation method and a membrane separation technology, and is characterized in that the average molecular weight of the alginic acid or a salt thereof is 5000-20,000 Between 1 and 3, and the molecular weight of most of the alginate molecules is in the range of 1000 to 30,000 Daltons, and its U.V. viscosity intrinsic viscosity is between 1 and 20, and Salt-forming cations are pharmaceutically acceptable cations or trivalent chromium ions.

2. The low molecular weight alginic acid or a salt thereof according to claim 1, which has an average molecular weight between 7000 and 12,000 Daltons, and the molecular weight of most of the alginate molecules is between 1000 and 20,000 Daltons. In the meanwhile, its Ubnose viscosity characteristic viscosity number is between 3-14.

3. The low molecular weight alginic acid or a salt thereof according to claim 2, which has an average molecular weight between 7000 and 9,000 Daltons, and the molecular weight of most of the alginate molecules is between 1200 and 10,000 Daltons. between.

4. A method for preparing a low-molecular-weight alginate, comprising: (1) degrading a high-molecular-weight alginic acid raw material to an average molecular weight of more than 20,000 to about 80,000 Daltons, adding an alkali solution to dissolve it; (2) Use ultrafiltration method to cut off molecules with molecular weight above 30,000 Daltons, leaving alginate molecules with molecular weight less than 30,000 Daltons, and (3) use nanofiltration membranes to cut off alginic acid with molecular weight less than 1000 Daltons Salt molecules to obtain an alginate having an average molecular weight between 5000-20,000 Daltons and most of the alginate molecules having a molecular weight in the range of 1,000-3,000 Daltons, and finally drying.

5. A method for preparing a low-molecular-weight alginate, comprising: (1) degrading a high-molecular-weight alginic acid raw material to a molecular weight of more than 20,000 to 80,000 Daltons; (2) treating the degradation product with alkali to make it soluble (3) adding water or an aqueous medium under stirring, and then adding an oxidant to further degrade the product into a lower molecular weight alginate, (4) using ultrafiltration to cut off molecules with a molecular weight of more than 30,000 Daltons, Alginate molecules with a molecular weight of less than 30,000 Daltons are left, and (5) alginate molecules with a molecular weight of less than 1000 Daltons are cut off with a nanofiltration membrane to obtain an average molecular weight between 5000 and 20000 Daltons and absolute Most of the alginate molecules have an alginate with a molecular weight in the range of 1,000 to 30,000 Daltons, and are finally dried.

6. A method for preparing a low-molecular-weight alginate, comprising: (1) degrading a high-molecular-weight alginic acid raw material to an average molecular weight of more than 10,000 to about 70,000 Daltons, adding an alkali solution to dissolve it; (2) Use ultrafiltration method to cut off molecules with molecular weight above 10,000 Daltons, leaving alginic acid molecules with molecular weight less than 10,000 Daltons, and (3) use nanofiltration membranes to cut off alginic acid molecules with molecular weights less than 1200 Daltons To obtain an alginate with an average molecular weight between 5000-8000 Daltons and the molecular weight of most of the alginate molecules in the range of 1200-1,0000 Daltons, and finally drying.

7. A method for preparing a low-molecular-weight alginate, comprising: (1) degrading a high-molecular-weight alginic acid raw material to a molecular weight of more than 10,000 to 70,000 Daltons; (2) treating the degradation product with alkali to make it soluble of