JPH0762001A - Method for carrying out desulfation of sulfated sugar - Google Patents

Abstract

PURPOSE:To produce desulfated sugar in which the position of sulfur group and desulfation ratio are efficiently controlled without causing side reactions, e.g. cleavage of glycoside bond by subjecting sulfated sugar to desulfation reaction in the presence of a specific silylating agent. CONSTITUTION:Sulfated sugar is subjected to desulfation reaction in a form of an organic solvent-soluble salt in the presence of a silylating agent expressed by the formula (R is alkyl or aryl) in an organic solvent. The salt is a salt of an organic base, e.g. pyridine or dimethylaniline. After finishing desulfation reaction, silyl group of a further silylated hydroxyl group is removed. As the sulfated sugar, glucosaminoglycan having a sulfuric acid group, e.g. heparin or chondroitin sulfate is used. The silylating agent is preferably 2- trimethylsiloxypento-2-ene-4-one.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for partially or completely desulfating a sulfate group of a sulfated sugar, and more specifically, a primary hydroxyl group and a secondary hydroxyl group among sulfate esters of a sulfated sugar. And a method capable of desulfating a sulfate group bonded to any of amino groups.

[0002]

2. Description of the Related Art Various methods for desulfating sulfated sugars have been studied in order to provide desulfated sugars having biological activity. As a method for desulfating a sulfated sugar, a method of desulfating with an acid catalyst in hydrogen chloride / methanol is known (Kantor TG and Schubert M., J. Amer. Chem. Soc.
79, 152 (1957)). However, in this method, the sugar chain is cleaved by the methanolysis of the glycoside bond, so that the molecular weight is reduced and the yield of the reaction product having the original chain length is reduced.

As a method for desulfurization with a good yield, a method such as dimethyl sulfoxide, N, N-dimethylformamide or pyridine in an aprotic solvent [Usov AI, Adamyant
s KS, Miroshnikova LI, Shaposhnikova AA and
Kochetkov NK, Carbohydr. Res. 18, 336 (1971)] or in dimethyl sulfoxide containing a small amount of water or methanol [Nagasawa K., Inoue Y. and Kamata T., Carbohyd.
r. Res., 58, 47 (1977), Nagasawa K., Inoue Y. and
Tokuyasu T, J. Biochem., 86, 1323 (1979)]. The reaction mechanism of this solvolysis is
It is known to be the reverse reaction of the sulfation reaction performed using a complex of sulfur trioxide and an amine in an aprotic solvent. This reaction can be used as a method for selectively desulfating the N-sulfate group by controlling the reaction conditions. However, it was not possible to eliminate the O-sulfate group bonded to the primary or secondary hydroxyl group.
Furthermore, when this method is applied to oligosaccharides, DMSO
There is a problem that the operation of removing the solvent such as after the reaction is complicated, the reaction temperature needs to be raised to completely desulfate, and the glycoside bond is cleaved under such reaction conditions. is there. On the other hand, there is a method of using N, O-bis (trimethylsilyl) acetamide (BTSA) as a method of specifically desulfating the sulfate group bonded to the primary hydroxyl group of the saccharide.
It is not possible to desulfate sulfate groups bound to primary hydroxyl groups or amino groups (Matsuo, M., Takano, R., Kamei-Hayash
i, K. and Hata, S., Carbohydr. Res. 241, 209-215, (19
93)). Further, when heparin was desulfated using BTSA, there was a problem that the desulfation rate was not high.

[0004]

The development of a method for desulfating sulfated sugar is very important for providing a sulfated sugar useful as a drug having a preferable biological activity for humans. For example, sulfated polysaccharides such as dextran sulfate, xylan sulfate, chondroitin sulfate, and heparin are used as lipid metabolism improving agents and antithrombotic agents, but those artificially introduced sulfate groups have introduced sulfate groups. It is also known that the position cannot be specified, and that the introduction of a large amount of sulfate groups causes a side effect of increasing the tendency of bleeding from the tissue. In addition, naturally occurring sulfated sugars have different positions and amounts of sulfate groups depending on their origins, and the physiological activities of the sulfated sugars are also slightly different. That is, there is a demand for a technique for efficiently controlling the position of the sulfate group of the sulfated sugar and the sulfation rate. The present inventors have conducted diligent studies to develop a desulfation method for sulfated sugars, which has a high desulfation rate and does not have side reactions such as cleavage of glycoside bonds, for the purpose of improving the biological activity of sulfated sugars. Has reached the present invention.

[0005]

The method of the present invention uses a sulfated sugar represented by the following formula (I):

[0006]

[Chemical 2] [Wherein R is the same or different and represents an alkyl group or an aryl group] and subjected to a desulfation reaction in the presence of a silylating agent. A wide range of specific positions were selectively desulfated. This is a method for producing desulfated sugar.

That is, according to the method of the present invention, the sulfate group bonded to any of the primary hydroxyl group, secondary hydroxyl group and amino group of the sulfated sugar can be efficiently desulfated. Further, it is possible to partially desulfate by controlling the reaction conditions.

The sulfated sugars to which the method of the present invention is applied are those in which functional groups of sugars such as monosaccharides, oligosaccharides, polysaccharides and complex polysaccharides are sulfated. Such a sulfated sugar may be a product extracted and isolated from a natural product or a product synthesized. In particular, the present invention is applied to glycosaminoglycans having a sulfate group such as heparin, heparan sulfate, chondroitin sulfate, dermatan sulfate, and keratan sulfate, in order to modify or improve the physiological activity of these sugars, it is necessary at a necessary position. It is useful for obtaining a sulfated sugar having a large number (degree of substitution) of sulfate groups bonded.

In the present invention, since the desulfation reaction is usually carried out in an organic solvent, the sulfated sugar is provided as a salt soluble in the organic solvent in the reaction. Examples of such an organic solvent-soluble salt include organic base salts of sulfated sugars, and examples of the organic base include aromatic amines such as pyridine, dimethylaniline and diethylaniline; trimethylamine, triethylamine, tributylamine, N, N- Diisopropylethylamine,
Tertiary amines such as trioctylamine, N, N, N ', N'-tetramethyl-1,8-naphthalenediamine; N-
Examples include N-alkylheterocyclic amines such as methylpyrimidine, N-ethylpyrimidine, N-methylmorpholine and N-ethylmorpholine. The organic base salt of sulfated sugar is
It can be easily obtained by reacting a free sulfated sugar with an organic base.

The desulfation reaction is usually carried out in an anhydrous organic solvent,
It is achieved by reacting the sulfated sugar with a silylating agent represented by the above formula (I). The organic solvent used for the reaction is preferably the above-mentioned organic base (pyridine or the like) used for forming a salt of a sulfated sugar, but instead of the organic base, acetonitrile, N, N-dimethylformamide (DMF),
Dimethyl sulfoxide (DMSO), N, N-dimethylacetamide, tetrahydrofuran (THF), 1,4
-An aprotic solvent such as dioxane may be used.

In the compound represented by formula (I) which is a silylating agent, R is the same or different and represents an alkyl group or an aryl group, preferably a lower alkyl group having 1 to 6 carbon atoms or a phenyl group. That is, as (R) ₃ SiO in the formula (I), trimethylsilyloxy, triethylsilyloxy, dimethylisopropylsilyloxy, isopropyldimethylsilyloxy, methyldi-t
-Butylsilyloxy, t-butyldimethylsilyloxy, t-butyldiphenylsilyloxy, triisopropylsilyloxy and the like are exemplified. The most preferable silylating agent represented by the formula (I) is 2-trimethylsiloxypent-2-en-4-one.

The reaction is completed in a few minutes to a few tens hours at room temperature to 100 ° C. At a temperature lower than room temperature, the reaction does not proceed sufficiently, and at a temperature of 100 ° C. or higher, the glycosidic bond of the sulfated sugar may be cleaved. The degree of desulfation can be controlled by changing the reaction conditions, especially the reaction temperature. For example, partial desulfation of existing sulfate groups can be performed at 70 to 80 ° C. for about 30 minutes to 6 hours, and more complete desulfation can be performed at 85 to 100 ° C. for about 10 minutes to several hours. It can be performed.

The amount of the silylating agent used is 2 to 1 mol of all hydroxyl groups of the sulfated sugar (all unsubstituted and substituted hydroxyl groups).
It is about 100 times mol. The degree of desulfation can also be controlled by changing the amount of silylating agent used. When partially desulfating, the silylating agent may be used in an amount of about 2 to 16 times, and when desulfurizing more completely, the silylating agent may be used in a larger amount.

After completion of the desulfation reaction, the unreacted silylating agent is made non-reactive to stop the reaction. For example, the object can be achieved by adding water to the reaction solution or / and dialysis of the reaction solution against water.

Thus, a desulfated sugar in which a sulfate group is partially or completely removed from the sulfated sugar can be obtained. After the desulfation reaction, the functional groups such as the hydroxyl groups of the desulfated sugar are silylated. For example, water is added to the reaction solution or /
And the silyl group is removed by dialyzing the reaction solution against water. Further, if necessary, the reaction for removing the silyl group can be carried out according to a conventional method. This reaction is carried out, for example, by placing the solution that has been subjected to the above treatment under alkaline conditions or heating conditions.

When the desulfated sugar has an anionic functional group, a counter ion corresponding to the anionic functional group can be present in the solution to form a salt. For example, add alkali metal hydroxide (sodium hydroxide, etc.) to an aqueous solution of desulfated sugar after silyl group removal reaction, dialyze as necessary, and then subject to freeze-drying or other dehydration step under non-heating conditions. Thus, an alkali metal salt of desulfated sugar can be obtained.

[0017]

EXAMPLES The present invention will be described in more detail with reference to Examples and Test Examples, but these do not limit the scope of the present invention in any way. The analysis of sulfated sugar was performed based on the following method.

Analyzing Method of Sulfated Sugar 1) Quantification of Sulfate Group Quantification of sulfate group of sulfated sugar and desulfated sugar was carried out by Shinsei Chemistry Laboratory Course 3, Sugar II p37, p81 (published by Tokyo Kagaku Dojin)
According to the method described in 1, the sulfate group is converted to a free sulfate ion by acid hydrolysis, and then the ion is adsorbed on an ion exchange resin, and then eluted with a solvent, and the free sulfate ion is measured using an electric conductivity meter. It was detected and quantified. That is, 30
1 ml of 3N-hydrochloric acid was added to 0 μg of sulfated sugar and hydrolyzed at 100 ° C. for 18 hours. The solution was dried and then dissolved in 1 ml of water. After filtering with a Millipore ultrafiltration membrane (0.45 μm), the sulfate ion content was determined by HPLC (Waters ILC-
It was analyzed by ion exchange chromatography according to 1). IC Pak Anion (Waters, 4.6mm × 5c on the column
flow rate of 0.8 ml / min using a mobile phase of composition 1.3 mM sodium tetraborate, 1.5 mM sodium gluconate, 6 mM boric acid, 0.25% glycerin and 12% acetonitrile. Deployed in. An electric conductivity meter (Waters 430) was used to detect sulfate ions.

2) ¹³ C-NMR The nuclear magnetic resonance spectrum of skeletal carbon was measured for the purpose of determining the properties of the hydroxyl group of the sulfated sugar. The spectrum of 10% sugar in heavy aqueous solution is 80 ° C, 75.4MHz (General Elec
toric Company, QE-300).

3) Structural analysis by enzymatic digestion Glycosaminoglycans (mucopolysaccharides) such as dermatan sulfate, chondroitin sulfate and heparin are sulfated at various positions of the constituent disaccharide units, and are subjected to the desulfation reaction according to the present invention. To know which position of sulfuric acid is removed,
It is important in modifying the physiological activity of these glycosaminoglycans.

Analysis of the position of the sulfate group of such glycosaminoglycan can be carried out as follows. That is, glycosaminoglycans before and after the treatment of desulfation reaction are enzymatically digested, and the resulting disaccharide containing unsaturated sugar (unsaturated disaccharide; see FIG. 1) is subjected to high performance liquid chromatography (HP).
LC) [Shinsei Chemistry Experiment Course 3, Carbohydrate II p4
See “Structural analysis combining 2.8 glycosaminoglycan degrading enzyme and HPLC” described in 9 to 62]. In addition, chondroitin sulfate and dermatan sulfate were enzymatically digested with chondroitinase ABC and heparin with heparin-degrading enzyme.

A) Digestion with chondroitinase ABC According to the method of Yoshida et al. [Biochemistry, 57, 1189 (1985)], an aqueous solution of dermatan sulfate and chondroitin sulfate (10 mg / m 2
l) 20 μl of 0.4 M Tris-HCl (pH 8.0) 20
μl, 0.4 M sodium acetate 20 μl, 0.1% bovine serum albumin 20 μl and water 120 μl, and chondroitinase ABC (5 U / mL) 20 μl was added.
The reaction was carried out at 7 ° C for 2 hours.

B) Digestion with heparin-degrading enzyme According to the method of New Experimental Biochemistry Course 3, Carbohydrate II p54-59 (published by Tokyo Kagaku Dojin), 0.1 mg heparin containing 20 mM sodium acetate containing 2 mM calcium acetate (pH 7. 0) 2
After dissolving in 20 μl, 20 mU of heparinase and 20 mU of heparitinase I and II were added and reacted at 37 ° C. for 2 hours. The sulfate group bonded to the amino group is eliminated by the desulfation treatment. The heparin-degrading enzyme does not act on such desulfated heparin. Therefore, it is necessary to acetylate the amino group prior to the enzymatic reaction. N
-Acetylation may be performed with sodium carbonate or Dowex.
ex) −1 (HCO ₃ ⁻ type) in an aqueous solution containing an ion exchange resin, the reaction proceeds quantitatively with acetic anhydride [see “Glycoengineering”, published by Biotechnology Information Center, Industrial Research Institute, Inc., page 324].

C) Analysis by HPLC 50 μl of the solution after digestion with chondroitinase ABC or heparin-degrading enzyme was analyzed by HPLC (medical science, model 852). Using an ion exchange column (Shimadzu PNH ₂ column, 4.0 mm x 250 mm), 2
Absorbance at 32 nm was measured. 16 mM at a flow rate of 1 ml / min
Sodium hydrogen phosphate was eluted by increasing it from 0% to 50% in 60 minutes. The peaks of the unsaturated disaccharides having sulfate groups at various positions eluted (the symbols in FIG. 2 represent the unsaturated disaccharides corresponding to the respective peaks) were identified.

4) Gel filtration 10 μl of a 3% solution of sulfated sugar was analyzed by gel filtration by HPLC. The column is TSKgel-G4000PW _X1 (Tosoh,
7.8 mm × 30 cm) and 0.2 M potassium sulfate was used as an eluent at a flow rate of 1.0 ml / min. A differential refractometer (Shimadzu, AID-2A) was used to detect the sulfated sugar.

Example 1 Methyl α-galactopyranoside-6-pyridinium sulfate (Gal-6S; 1.142 mg / ml) and methyl α
-Galactopyranoside-3 pyridinium sulfate salt (Gal
-3S; 0.849 mg / ml each),
Methyl α-glucopyranoside (Me-Gl) was added to 100 μl of each as an internal standard for gas chromatography analysis.
100 μl of the aqueous solution of c) (1.000 mg / ml) was added and freeze-dried to obtain a sample for the desulfation reaction. To the freeze-dried sample, 100 µl of dried pyridine and 100 µl of 2-trimethylsiloxypent-2-en-4-one (hereinafter referred to as TPENON) were added, and the tube was heated at 40 ° C for 5 hours for desulfation reaction. For complete O-trimethylsilylation and gas chromatographic analysis, trimethylsilylimidazole was added to the reaction solution and heated at 80 ° C. for 20 minutes. Each 1 μl of this solution was analyzed by gas chromatography to quantify the amount of released methyl α-galactopyranoside.
%, And 10.91% of Gal-3S was desulfated. In addition, when the sulfate group of each sulfated sugar was quantified before and after the TPEON treatment, it was found that Gla-6S and Gal-before the treatment were treated.
The content of sulfate groups in 3S was 35.1%, but TP
After ENON treatment, 16.5% and 30.8, respectively
%Met. As is clear from this result, TPENO
The use of N makes it possible to desulfate both the sulfuric acid group bonded to the primary hydroxyl group and the secondary hydroxyl group. On the other hand, when a similar reaction was carried out using a known BTSA as a desulfating agent, Gal-6S was almost completely desulfated, but Gal-3S was only 2.12% desulfated. That is, even if BTSA is used, the sulfate group bonded to the secondary hydroxyl group is hardly desulfated.

Example 2 and Comparative Example 1 200 mg of heparin-pyridinium salt (see the following Table 2 for the position and amount ratio of the sulfate group) was dissolved in 20 ml of dry pyridine, and 4 ml of TPENON was added thereto and the tube was sealed. 70
After heating at ℃ for 2 hours, the reaction solution was added to a large excess of water to 1
I dialyzed at night. The dialyzed solution was adjusted to pH 9 with a 1N sodium hydroxide solution, and dialyzed again against a large excess of water for 3 days. During this period, the water of the dialysis external solution was changed twice a day. After dialysis, the non-dialyzed fraction is freeze-dried to partially desulfate heparin-
The sodium salt was obtained (yield 138 mg). On the other hand, as a comparative example, 186 mg of heparin-tributylammonium salt was dissolved in 20 ml of dry pyridine, 4 ml of BTSA was added thereto, and the mixture was allowed to stand at 20 ° C. for 30 minutes. The reaction solution was dialyzed overnight against a large excess of water. The dialyzed solution was adjusted to pH 9 to 10 by adding a 1N sodium hydroxide solution, and dialyzed again against a large excess of water for 3 days. During this period, the water of the dialysis external solution was changed twice a day. After dialysis, the non-dialysis fraction was lyophilized to obtain partially desulfated heparin-sodium salt (yield 140 m
g). Desulfated heparin obtained by each of the above methods
The results of various analyzes of sodium salts are shown in Table 1.

[0028]

[Table 1]

In the table, the uronic acid content was measured by carbazole-sulfuric acid method (T. Bitter,
Measured by by HNMuir improved method), was calculated uronic acid as _{-C 6 H 7 O 6 Na- (} Mw = 198). Content sulfate groups, determined by rhodizonate method to calculate the sulfate group as -SO ₃ Na. The molar ratio was calculated by correcting the molar ratio of uronic acid in heparin in the carbazole / sulfuric acid method, which is 50% higher than usual. The ¹³ C-NMR spectrum was measured for heparin desulfated with TPEON. For comparison, untreated heparin and heparin N-desulfated by solvolysis [Y. Inoue et al, Carbohydr.
s., 46, 87-95 (1976)] and fully desulfated heparin [A. Ogamo et al, Carbohydr. Res., 193, 165-172.
(According to the method of (1989)] was also measured for ¹³ C-NMR spectrum. As a result, iduronic acid 2-sulfuric acid (Id
oA-2S) is partially desorbed (IdoA
-2S C-1 peak and iduronic acid (IdoA)
C-1 peak of) appeared, 6 of the glucosamine part
-Sulfuric acid was desorbed (the peak of C-6 of glucosamine appeared), Part of 6-sulfate of the glucosamine moiety was desorbed (glucosamine 6-of N-desulfated heparin)
A peak at the same position as C-1 of glucosamine of fully desulfated heparin appeared on the left side of the peak at the same position as the peak of C-1 of sulfuric acid).

Example 3 and Comparative Example 2 200 mg of chondroitin sulfate-pyridinium salt (from shark; 6-sulfuric acid: 4-sulfuric acid: 4,6-disulfuric acid ratio shown in Table 3 below) was dissolved in 20 ml of dry pyridine. , This is T
4 ml of PENON was added and the tube was sealed. After heating at 70 ° C. for 2 hours, the same operation as in Example 2 was carried out to obtain partially desulfated chondroitin sulfate-sodium salt (yield 156 mg). TP
When the sulfate group was quantified before and after the ENON treatment, the sulfate group content before the treatment was 19.8%, but it was 3.6% after the TPEON treatment. On the other hand, as Comparative Example 2,
Chondroitin sulfate-pyridinium salt 200 mg, BT
Reaction and purification were carried out by the same procedure as above except that 4 ml of SA was used to obtain partially desulfated chondroitin sulfate-sodium salt. ¹³ C-NMR spectra of the above reaction products and untreated chondroitin sulfate were measured. As a result, in TPEON-treated chondroitin sulfate, the peak derived from chondroitin 4-sulfate disappeared and all were desulfated to produce chondroitin, which simplified the peak, but in BTSA-treated chondroitin sulfate, 6-sulfate was desulfurized. Both peaks of chondroitin and chondroitin 4-sulfate produced by oxidation were observed.

Example 4 200 mg of dermatan sulfate-pyridinium salt (refer to Table 4 below for the amount ratio of 6-sulfate: 4-sulfate: 4,6-disulfate)
Is dissolved in 20 ml of dry pyridine and TPENON4 is added to it.
ml was added and the tube was sealed. After heating at 70 ° C. for 2 hours, the same operation as in Example 2 was carried out to obtain partially desulfated dermatan sulfate-sodium salt (yield 148 mg). Sulfate group was quantified before and after the TPEON treatment, and the sulfate group content before treatment was 1
It was 5.3%, but 4.4% after TPEON treatment.
It was. ¹³ C-NMR spectra of the above reaction product and untreated dermatan sulfate were measured. As a result, a peak derived from C-4 of N-acetyl-D-galactosamine produced by desulfation appeared, and the pattern of the peak of C-1 of iduronic acid was changed.

Test Example (1) Structural Analysis by Enzymatic Digestion In order to investigate the detailed structural changes of the partially desulfated heparin, chondroitin sulfate, and dermatan sulfate obtained in Examples 2 to 4, disaccharides were examined. The unit was enzymatically digested and analyzed by HPLC. For comparison, each sulfated sugar that had not been desulfated was also analyzed. The HPLC fractional chromatograms of various isomers of unsaturated disaccharide (FIG. 1) produced by enzymatic digestion are shown in FIG. In addition, the quantitative ratio (%) of the HPLC fractions of various isomers
Table 2 shows heparin, Table 3 shows chondroitin sulfate, and Table 4 shows dermatan sulfate.

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

[Table 4]

The following is clear from FIG. 2 and Tables 2-4. That is, in heparin, ΔDiHS- in which all of the 2-position hydroxyl group of uronic acid, 2-position amino group and 6-position hydroxyl group of glucosamine were sulfated by TPEON treatment.
ΔDiHs-OS (all desulfated) and ΔDiHS-di (U, 6) S (the 2-position of uronic acid and glucosamine) in which tri (U, 6, N) S was almost absent and hardly existed or not existed at all. (Sulfated at the 6-position) was significantly increased. That is, the sulfate group bonded to the amino group at the 2-position was significantly reduced, and other sulfate groups were also significantly reduced. 6-sulfate, 4 in chondoitin sulfate
-A mixture of sulfuric acid, 4,6-disulfuric acid, etc. was used, but TPE
Di-6S in which the 6-position hydroxyl group of galactosamine was sulfated by NON treatment and Δ in which the 4-position hydroxyl group was sulfated
Di-4S was significantly reduced, and ΔDi-0S (all desulfated) was significantly increased. Most of dermatan sulfate was 4-sulfuric acid and a small amount of 6-sulfuric acid was used. However, ΔDi-4S in which the 4-hydroxyl group of galactosamine was sulfated by TPEON treatment.
Was significantly reduced, and ΔDi0S (all desulfated) was significantly increased.

(2) Gel filtration The molecular weight changes of heparin, chondroitin sulfate, and dermatan sulfate before and after the TPEON treatment were examined by gel filtration, and the results are shown in Table 5.

[0038]

[Table 5]

As shown in Table 5, almost no change in the molecular weight distribution was observed, and the glycoside bond cleavage (reduction of molecular weight) of the sulfated sugar by TPEON treatment did not occur.

[0040]

The desulfation reaction according to the present invention is carried out by BTSA.
Unlike the case of using, the sulfate group bound to the amino group is desulfated preferentially, but the sulfate group bound to either the primary hydroxyl group or the secondary hydroxyl group is efficiently desulfated. However, this method does not affect the glycosidic bond. That is, desulfation proceeds by a mechanism different from the desulfation by BTSA specific for the sulfate group (eg, 6-O-sulfate group of heparin or chondroitin 6-sulfate) bonded to the primary hydroxyl group. Conceivable. Also,
Compared with desulfation by BTSA, more complete desulfation can be performed, and partial desulfation can also be performed by controlling the reaction conditions.

[Brief description of drawings]

FIG. 1 shows the structure and abbreviation of various isomers of various unsaturated disaccharides produced by enzymatic digestion of glycosaminoglycan.

FIG. 2 is a graph showing an HPLC fractionation chromatogram of various isomers of unsaturated disaccharide produced by enzymatic digestion.

Claims (5)

[Claims] 1. A sulfated sugar is represented by the following formula (I): [Wherein, R is the same or different and represents an alkyl group or an aryl group] and is subjected to a desulfation reaction in the presence of a silylating agent. 2. The method for producing a desulfated sugar according to claim 1, wherein the sulfated sugar is a salt soluble in an organic solvent and the reaction is carried out in an organic solvent. 3. The method for producing a desulfated sugar according to claim 2, wherein the organic solvent-soluble salt of sulfated sugar is an organic base salt of sulfated sugar. 4. The method for producing a desulfated sugar according to claim 2, wherein the organic solvent is capable of dissolving an organic solvent-soluble salt of sulfated sugar. 5. The method for producing a desulfated sugar according to claim 1, wherein the silyl group of the silylated hydroxyl group is further removed after the desulfation reaction.