JPH1067804A - Chitosan derivative, its production and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a novel chitosan derivative having excellent solubility, having little astringent bitterness and being very stable and useful for drugs and foods by reducing a specified chitosan. SOLUTION: This derivative is obtained by partially deacetylating chitin and reducing the product of partial deacetylation. It is desirably one having a degree of deacetylation of 20-80%. It is more desirably one having an average molecular weight of 50,000-500,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel chitosan derivative, a method for producing the same, and a medicament or food containing the same. More specifically, the present invention relates to a chitosan derivative obtained by subjecting partially deacetylated chitosan to a reduction treatment, a method for producing the same, and a medicament or food comprising this and an indigestible dextrin having a constipation improving effect.

[0002] In recent years, reported crab, chitosan obtained chitin which is a component of the shells of crustaceans shrimp or the like by deacetylation to inhibit the absorption interact with cholesterol and bile acids,
Its effective use is attracting attention in the food field [M. Sugano et
al: Lipid, 23,187 (1988), Y. Maejima et al: Bios
ci. Biotech. Biochem., 57, 1439 (1993)].

At present, chitosan has already been commercialized in the form of powder, tablets, and soft capsules. However, chitosan used in these products hardly dissolves in water, and when commercialized as a liquid preparation such as a drink, Organic acids such as lactic acid and acetic acid must be used. In addition, chitosan is known to form a complex salt with minerals such as iron, magnesium and calcium, and if taken in a large amount, it may inhibit the absorption of nutrient minerals. Furthermore, chitosan has an intense astringent astringent taste, and it is not preferable to mix it into drinks, powders, powders and the like.

Various studies have been made to solve such problems. For example, low molecular weight chitosan has been developed to increase the solubility of chitosan. However, the cholesterol lowering effect of chitosan is remarkably reduced due to the reduction in molecular weight, and further, a browning reaction is easily caused, and there is a problem in stability.

[0005] Also, in order to reduce the astringency of chitosan,
Masking of taste using various additives has been studied (JP-A-2-283261). However, no sufficient improvement has yet been found.

On the other hand, when chitin is partially deacetylated,
It is known that soluble chitosan can be obtained with a degree of deacetylation of about 50% [Sannan, S. et al. et al: Macromo
l. Chem., 177, 3589 (1976), the last biomass chitin, chitosan, 1988)]. However, no detailed studies have been made on the physical properties, stability, pharmacological action, mass production method and the like of this chitosan derivative, and the chitosan derivative has not been put to practical use. In addition, according to experiments conducted by the present inventors, these partially acetylated forms are liable to cause a browning reaction and lack stability.

In recent years, with the improvement of dietary habits and the westernization, the intake of cereal foods containing complex polysaccharides such as starch has decreased, and the intake of high-energy fat foods or refined processed foods has increased. Along with that, so-called adult diseases such as constipation, diabetes, hyperlipidemia, hypertension increase,
It is becoming a big social problem. In particular, long-term constipation causes not only discomfort but also fecal impaction that accumulates in the intestinal wall of the large intestine, and this fecal impaction is said to cause various diseases such as colorectal cancer [Burkitt, DP: Cancer, 28]. , 3 (1971),
Burkitt, DP et al: Lancet, 30, 1408 (1972)].

[0008] Drugs for the purpose of improving constipation are mainly photowashing drugs,
For example, salt laxatives such as magnesium oxide, swelling laxatives such as carmellose calcium, irritative laxatives such as bisacodyl, and steep laxatives such as castor oil are commonly used. However, all of these drugs have the drawback of causing discomfort such as abdominal pain when taken, and also include the risk of dehydration due to severe diarrhea. Therefore, products containing dietary fiber such as polydextrose and cellulose have been developed with the expectation of a milder effect.However, the effect of promoting defecation is greatly affected by the fiber content in dietary fiber, High intake causes inhibition of absorption of minerals such as iron, magnesium, and calcium [Makoto Nomura, et al .: Clinical Nutrition, 13,
141 (1992)], etc., and sufficient product development has not yet been made.

[0009]

SUMMARY OF THE INVENTION The present inventors have now reported that by further reducing a partially deacetylated chitosan, an extremely stable chitosan derivative having excellent solubility and almost no astringent astringent taste can be obtained. Was obtained. Furthermore, they have found that this chitosan derivative has an activity equivalent to that of conventionally known chitosan, and that it has an excellent defecation promoting effect when combined with indigestible dextrin. The present invention is based on this finding.

[0010] Accordingly, an object of the present invention is to provide a chitosan derivative which is stable, has no taste and is effective, and a method for producing the same.

Another object of the present invention is to provide a medicament or food containing the above chitosan derivative, particularly a medicament or food having a constipation improving effect.

The chitosan derivative according to the present invention is
It can be obtained by partially deacetylating chitin and then reducing it.

The medicament or food according to the present invention, especially a medicament or food having a constipation-improving action, comprises the above-described chitosan derivative according to the present invention and, in some cases, dietary fiber.

[0014]

DETAILED DESCRIPTION OF THE INVENTION Chitosan Derivatives and Method for Producing The Chitosan Derivatives of the present invention can be obtained by partially deacetylating chitin and then reducing. More specifically, the chitosan derivative according to the present invention is obtained by subjecting purified chitin to an alkali treatment at a low temperature to partially deacetylate,
It is obtained by reducing the terminal aldehyde. Preferably, the reduction is with a borohydride reducing agent such as sodium borohydride. This reduction may be performed by another reduction method, but the degree of the reduction is preferably the same as that of sodium borohydride.

The chitosan derivative according to the present invention has an equivalent water solubility as compared with the partially deacetylated chitosan derivative before being subjected to the reduction treatment. Furthermore, it has the advantage that it has almost no taste and odor, is excellent in stability, and hardly discolors even under warm storage.

According to a preferred embodiment of the present invention, the degree of deacetylation is preferably about 20 to 80%, more preferably 40 to 60%. Further, according to a preferred embodiment of the present invention, the average molecular weight of the chitosan derivative is from 50,000 to 5
It is preferably about 000, more preferably 100,000.
It is about 000 to 300,000.

The structure of the chitosan derivative according to the present invention is considered to be a mixture of chitosan derivatives having a plurality of types of structures. On the other hand, if the chitosan derivative is obtained by partial deacetylation followed by reduction treatment, Due to the above advantages, it may be understood that the identification of the structure is not essential to the practice of the invention. However, as one expected embodiment of the present invention, the chitosan derivative according to the present invention is considered to be a compound represented by the following formula (I).

[0018]

Embedded image (Wherein, n represents an integer of 20 to 1400, R represents a hydrogen atom or a group COCH ₃ , provided that all R
20 to 80% of a group COCH _3).

Further, in some cases, the compound represented by the above formula (I) is further reduced by the above reduction treatment,
The structure may be a chitosan derivative represented by the following formula (II).

[0020]

Embedded image (Wherein, n represents an integer of 20 to 1400, R represents a hydrogen atom or a group COCH ₃ , provided that all R
20 to 80% of a group COCH _3).

Therefore, the chitosan derivative according to the present invention may be a mixture of the compound represented by the above formula (I) and the chitosan derivative represented by the above formula (II) in some cases.

The method for producing a chitosan derivative according to the present invention comprises:
It comprises a step of partially deacetylating chitin and a step of reducing the partially deacetylated product. The reduction treatment step is specifically a step of reducing the terminal aldehyde of the partially deacetylated product. The partial deacetylation step and the reduction treatment step may be performed according to known reactions. That is, partial deacetylation of chitin may be carried out by a known de-N-acetylation method, and can be preferably carried out by hydrolysis with heating with an alkali or an acid. As described above, the reduction treatment is preferably performed using a borohydride reducing agent such as sodium borohydride. In the method for producing a chitosan derivative according to the present invention, the partial deacetylation and the reduction treatment may be performed simultaneously.

Use of chitosan derivative / has constipation improving effect
The chitosan derivative according to the present invention has the property that its water solubility is improved, its taste and odor are almost non-existent, its stability is excellent, and it hardly discolors even under heated storage. In its biological activity, it is equivalent to chitosan previously known. Therefore, the chitosan derivative according to the present invention can be basically used for conventionally known applications of chitosan and its derivatives. Specifically, the chitosan derivative according to the present invention may be used for the following applications as it is or as a composition mixed with a carrier and optionally other biologically active compounds. That is, food preservatives (utilizing the antibacterial properties of chitosan), health foods (for example, utilizing the cholesterol lowering effect of chitosan), Drug Delivery System (DDS) carriers, microcapsules, artificial skin, surgical sutures, flocculants (chitosan (Using the action of agglutinating microorganisms), chromatography supports (ion exchange, affinity chromatography), separation functional membranes and the like.

Further, the present inventors have found that the chitosan derivative according to the present invention has a constipation improving effect. This constipation-improving effect can be further improved by using it together with dietary fiber, preferably indigestible dextrin.

Thus, according to the present invention, there is provided a pharmaceutical composition or food comprising the chitosan derivative according to the present invention, specifically, a pharmaceutical composition or food having a constipation improving effect.

The indigestible dextrin used in the present invention is known per se.
7, 107 (1990), or a commercially available product can be used. The combination of the chitosan derivative and the indigestible dextrin may be appropriately determined within a range in which the constipation-improving effect is obtained. For example, the weight ratio is preferably about 1: 1 to 1: 1000, more preferably 1: 2. About 1: 500.

Since both the chitosan derivative and the indigestible dextrin are water-soluble, they can be used as liquids or beverages. In addition, it can be made into ordinary pharmaceutical and food forms, for example, tablets, capsules, granules, powders and the like according to a conventional method. Further, it may be in a form mixed with everyday food or food ingredients.

If necessary, usual excipients, binders, preservatives, sweeteners, vitamins, flavors, minerals and other auxiliary components may be added. For example, iron, hem iron,
Iron lactate, iron citrate, ferrous pyrophosphate, calcium,
One or several minerals selected from calcium, gluconate, calcium lactate, calcium carbonate and the like, magnesium, magnesium chloride, magnesium sulfate and the like can be blended.

The daily intake is usually 1 to 20 g / 60 kg in total of the chitosan derivative and the indigestible dextrin.
Weight is preferred.

The indigestible dextrins and chitosans described above have already been used as food additives, and their safety has been confirmed. Further, the chitosan derivative of the present invention obtained by the reduction treatment has no problem in safety.

[0031]

EXAMPLES The present invention will be described in detail with reference to the following Examples, but the present invention is not limited to these Examples.

Example 1 Production Method of Chitosan Derivative (Part 1) 30 g of powdered chitin (80-mesh sieved product) was suspended in 700 g of a 40% sodium hydroxide solution and allowed to stand at 25 ° C. under reduced pressure for 3 hours. While stirring the suspension, 2.3 kg of crushed ice was added thereto, and the suspension was left at 25 ° C. for 77 hours. The solution was cooled to about 5 ° C., and 2 kg of ice was added.
The pH was adjusted to 8.5 with hydrochloric acid and dilute hydrochloric acid. Subsequently, the reaction solution was added dropwise to 20 liters of an acetone / water mixture (acetone: water = 7: 1) cooled to 0 ° C., and the formed precipitate was filtered and washed with an acetone / water mixture. After drying under reduced pressure, a white fibrous partially deacetylated chitosan 21 was obtained.
g was obtained.

20 g of the partially deacetylated chitosan obtained
In 2 liters of water and 2 g of sodium borohydride
After stirring at room temperature for 12 hours, the reaction solution was added dropwise to 10 liters of a mixture of acetone and water. The resulting precipitate was filtered, washed with acetone / water mixture, and dried under reduced pressure.
A chitosan derivative was obtained (degree of deacetylation: 49.5).
%).

Example 2 Production of Chitosan Derivative (Part 2) 30 g of powdered chitin (80-mesh sieved product) was suspended in 700 g of a 40% sodium hydroxide solution and allowed to stand at 25 ° C. under reduced pressure for 3 hours. While stirring this suspension, 2.3 kg of crushed ice was added thereto, and sodium borohydride 2 was added.
g was added and left at 25 ° C. for 77 hours. About 5
After cooling to ℃, 2 kg of ice was further added, and the pH was adjusted to 8.5 with hydrochloric acid and dilute hydrochloric acid. Subsequently, the reaction solution was cooled to 0 ° C.
-Water mixture (acetone: water = 7: 1)
The resulting precipitate was filtered, washed with a mixed solution of acetone and water, and dried under reduced pressure to obtain a chitosan derivative (degree of deacetylation: 50.5%).

Example 3 : Stability of chitosan derivatives Chitosan derivatives according to the invention (degree of deacetylation: 50.
2%) aqueous solution (1% solution) at 50 ° C. and 60 ° C.
The solution was stored for 4 days, and its stability was examined using the change in color difference of the solution as an index. The color difference was measured using a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd.) with a sample stored at 4 ° C. as a control.

For comparison, a non-reduced partially deacetylated chitosan solution (average molecular weight: 20500, degree of deacetylation: 47%; manufactured by Koyo Chemical) and a low molecular weight chitosan solution (average molecular weight: 4000, degree of deacetylation: 69.7) %;
(Manufactured by Kyowa Technos) (both are 1% solutions), and glucose and ferrous lactate are added to each solution at 12% and 0.02%, respectively.
The solution to which 12% was added was similarly evaluated.

The results were as shown in Table 1 below.

Furthermore, the chitosan derivative according to the present invention did not cause any precipitation due to the formation of a complex salt with iron ions, and was excellent in stability. Table 1 Stability of chitosan Color difference (ΔE value) Storage at 50 ° C Storage at 60 ° C Chitosan derivative of the present invention alone 0.22 0.15 (no change) Glucose + iron 0.12 0.25 (no change) Low molecular weight chitosan alone 2.80 6.16 (yellowing) Glucose + iron 2.89 12.81 (browning) Non-reduced chitosan alone 1.56 2.05 (slightly yellowing) Glucose + iron 2.71 3.52 (slightly yellowing ) )

Example 4 : Sensory test on taste Chitosan derivatives according to the present invention (degree of deacetylation: 50.2%), low molecular weight chitosan (same as in Example 3) for healthy persons (5 males and 3 females) ) And commercially available chitosan (degree of deacetylation: 88.3%) powder and solution were each subjected to sensory tests. The astringency of each solution was evaluated according to the following criteria, and the average score of each person's evaluation was obtained as an evaluation value. The results were as shown in Table 2 below. * Commercial chitosan solution was prepared with 0.1% lactic acid solution.

Example 5 : Defecation-promoting effect Three types of water-soluble dietary fiber, indigestible dextrin, corn fiber, or polydextrose were added to one.
20 g and 10 g of partially deacetylated chitosan (degree of deacetylation: 50.2%) were dissolved in purified water to prepare test solutions having compositions as shown in Table 3 below. Each test solution was prepared using sodium chloride, potassium chloride, citric acid and sodium citrate in an almost isotonic solution (2
85-295 mOsm). Table 3 Composition of test solution Experimental example 1 Experimental example 2 Experimental example 3 Indigestible dextrin 12%--corn fiber-12%-polydextrose--12% Chitosan derivative of the present invention 1% 1% 1% Sodium chloride 0. 117% 0.117% 0.117% Potassium chloride 0.037% 0.037% 0.037% Sodium citrate qs qs qq citric acid 0.168% 0.168% 0.168% Refined commercial feed (CLEA Japan) 5% chromic oxide
The mixture was added and stirred uniformly to prepare a standard feed. 1 g of this standard feed was given to mice fasted for 12 hours, and 2 hours later, the test solution and physiological saline (control solution) prepared above were orally administered at 30 ml / kg (0.9 ml / animal). After the administration, each animal was housed in a breeding gauge, and fed and watered. After administration of the test solution, excreted feces were observed every 30 minutes, and the time until green feces (feces colored with chromic oxide) was excreted was measured, and this was defined as defecation time.

The results were as shown in Table 4 below. As is clear from the table, the test solution containing dietary fiber and the chitosan derivative according to the present invention exhibited a defecation-promoting effect, and in particular, Experimental Example 1 in which indigestible dextrin was added significantly promoted defecation. *: P <0.05

Example 5 : Cholesterol-lowering effect SD male rats (3.5 weeks of age) were bred for 6 days with powdered CE-2 diet (manufactured by CLEA Japan), using blood total cholesterol, triglyceride, and body weight as indices. 8 per group
The animals were divided into groups. Each group was fed the experimental diet shown in Table 5 below for 20 days. All numerical values in the table are% by weight. Table 5 Composition of experimental feed Example 4 Example 5 Control feed A Control feed B Sucrose 60.17 49.17 60.17 60.17 Casein 20 20 20 20 20 lard 10 10 10 10 Vitamin 111 1 1 1 Mineral 4 545 Choline bitartrate 0.2 0.2 0.2 0.2 0.2 Cholesterol 0.5 0.5 0.5 0.5 Sodium cholate 0.13 0.13 0.13 0.13 Microcrystalline cellulose-- 4 - commercially available chitosan ^{* 1} - - - chitosan derivative according to 4 the invention ^* 2 4 4 - - indigestible dextrin - 10 - - * 1: The degree of deacetylation: 88.3% * 2: degree of deacetylation: 50 Then, blood was collected from the tail vein to measure plasma cholesterol, triglyceride, and total lipid. In addition, the liver weight and the epididymal fat content of each rat were measured. The feed was freely fed.

The above results were as shown in Table 6 below. Table 6 Weight gain and blood biochemical parameters Weight gain Serum total cholesterol Serum total lipid Serum phospholipid (g) (mg / dl) (mg / dl) (mg / dl) Example 4 group 158.7 ± 9.5 198.6 ± 26.1 * 515.9 ± 31.8 * 132.5 ± 6.4 * Example 5 group 158.4 ± 4.4 192.5 ± 21.1 * 501.0 ± 29.7 * 129.7 ± 5.3 * Control feed A group 156.6 ± 7.6 450.5 ± 53.0 821.5 ± 72.5 176.1 ± 12.2 Control feed B group 161.3 ± 4.7 190.9 ± 12.3 * 496.0 ± 36.5 * 133.9 ± 5.4 * *: P <0.05 Table 7 Organ weight Liver weight Testis attached fat weight (g / 100g body weight) (g / 100g body weight) Control feed group 4.57 ± 0.12 1.17 ± 0.13 A feed group 4.28 ± 0.15 1.11 ± 0.09 B feed group 4.04 ± 0.10 * 1.05 ± 0.09 C feed group 4 .01 ± 0.06 * 0.94 ± 0.10 *: P <0.05 As can be seen from the table, the chitosan derivative according to the present invention is included. In the group fed the diet, all blood biochemical parameters were significantly reduced compared to the control diet group, and the chitosan derivative according to the present invention had the same strong cholesterol lowering action and lipid absorption inhibitory action as commercial chitosan. I understood.

The liver weight of the commercial chitosan-containing diet group showed a tendency to decrease as compared with the control diet group. On the other hand, in the diet containing the chitosan derivative according to the present invention, the liver weight was clearly reduced. Furthermore, fatty liver findings were observed in the control feed group, but were hardly observed in the chitosan derivative-containing feed group according to the present invention. In addition, the weight of testis-adhered fat, which is an indicator of visceral fat, showed a decreasing tendency in the chitosan derivative-containing feed group according to the present invention. From these results, it is clear that the chitosan derivative according to the present invention is a material having a cholesterol lowering and lipid absorption inhibiting action.

Example 6 : Formulation examples / granules The compositions shown in the following Table 8 were mixed in a mixer (PM-5W, manufactured by Kikusui Seisakusho), kneaded with water, and extruded. (DOME GRAN, made by Fuji Paudal) 0.8m in diameter
m, and the resulting mixture was sized, dried, and sieved to obtain granules. The granules are excellent in disintegration in the stomach and can be provided in a packaged form such as a divided package.

Example 7 : Formulation Example / Tablets The respective components were mixed according to the composition shown in Table 9 below, and the diameter was 8 mm using a tableting machine (Collect 19K, manufactured by Kikusui Seisakusho).
Tablets weighing 150 mg were produced. This tablet was excellent in tableting properties, hardness and disintegration in the stomach.

Example 8 : Formulation examples / drinks Drinks having the compositions shown in Table 10 below were prepared as trials.
This drink was excellent in solubility and stability.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Sumihiro Shiraishi 1624 Shimokodate, Koda-cho, Takada-gun, Hiroshima Pref. Yukinaga Pharmaceutical Co., Ltd.

Claims (12)

[Claims] 1. A chitosan derivative which can be obtained by partially deacetylating chitin and then reducing it. 2. The chitosan derivative according to claim 1, wherein the degree of deacetylation is from 20 to 80%. 3. An average molecular weight of 50,000 to 500,000.
The chitosan derivative according to claim 1, which is 0. 4. A compound represented by the following formula (I):
The chitosan derivative according to claim 3. Embedded image (Wherein, n represents an integer of 20 to 1400, R represents a hydrogen atom or a group COCH ₃ , provided that all R
20 to 80% of a group COCH _3). 5. A method for producing a chitosan derivative, comprising a step of partially deacetylating chitin followed by a reduction treatment. 6. The method according to claim 5, wherein the degree of deacetylation is 40 to 60%. 7. A composition comprising the chitosan derivative according to claim 1. 8. The composition according to claim 7, further comprising a chitosan derivative represented by the formula (II). Embedded image (Wherein, n represents an integer of 20 to 1400, R represents a hydrogen atom or a group COCH ₃ , provided that all R
20 to 80% of a group COCH _3). 9. The composition according to claim 7, which is a pharmaceutical composition or a food. 10. A chitosan derivative according to any one of claims 1 to 4 or a composition according to claim 7 or 8,
Pharmaceutical composition or food comprising dietary fiber. 11. The pharmaceutical composition or food according to claim 10, wherein the dietary fiber is an indigestible dextrin. 12. The pharmaceutical composition or food according to claim 10, which has a constipation improving effect.