CN117264089A

CN117264089A - Brown algae heteropolysaccharide and application thereof

Info

Publication number: CN117264089A
Application number: CN202311531632.6A
Authority: CN
Inventors: 吴宁; 耿丽华; 张全斌; 王晶; 岳洋
Original assignee: Institute of Oceanology of CAS
Current assignee: Institute of Oceanology of CAS
Priority date: 2023-11-17
Filing date: 2023-11-17
Publication date: 2023-12-22
Anticipated expiration: 2043-11-17
Also published as: CN117264089B

Abstract

The invention discloses brown algae heteropolysaccharide and application thereof, and belongs to the technical field of marine organism resource high-valued application. The brown algae heteropolysaccharide comprises the following components in percentage by mass: 30-90% of polyglucuronic acid, 1-70% of heterozygous mannuronate and 0.1-30% of low-sulfation heterozygous glucan; the total mass fraction of polyglucuronic acid, heterozygous mannuronate and low-sulfation heterozygous glucan is not less than 90%; the brown algae heteropolysaccharide does not contain fucose. The brown algae heteropolysaccharide with specific component content is obtained by limiting the extraction steps, and has the functions of reducing uric acid, improving renal function and resisting inflammation for hyperuricemia and acute gouty arthritis. Can be used for preparing medicines, functional foods or health care products for preventing and treating hyperuricemia, gout and gouty arthritis.

Description

Brown algae heteropolysaccharide and application thereof

Technical Field

The invention belongs to the technical field of marine organism resource high-valued application, and particularly relates to brown algae heteropolysaccharide and application thereof.

Background

Hyperuricemia refers to a state in which the body is disturbed in purine metabolism, uric acid is hypersecretion or renal excretion is dysfunctional, and uric acid is accumulated in the blood. Hyperuricemia is a pathological condition of gout disease, which is painful inflammation of joints, synovial fluid and other tissues caused by deposition of urate crystals in joints, and continuous high concentration of uric acid in blood is a necessary condition for causing gout. In recent years, the prevalence of hyperuricemia and gout has been continuously increasing, and a trend of younger is presented, and based on online user investigation, the proportion of younger hyperuricemia and gout patients of 18-35 years old has reached 60%. The eastern coastal region is a main dense region for gout patients because seafood is favored, and alcoholism, irregular diet and bad living habits further cause the occurrence of high uric acid. Hyperuricemia has become a fourth important risk factor following hypertension, hyperlipidemia and hyperglycemia. Therefore, uric acid lowering drugs are dominant in the treatment of hyperuricemia and gout.

At present, the common clinical chemical medicines such as colchicine and the like can quickly and effectively relieve pain and inflammation of patients, but the medicines have more adverse reactions and can cause toxic and side effects such as liver damage, nervous system adverse reactions and the like with different degrees. Other drugs commonly used in clinic for inhibiting uric acid synthesis, such as allopurinol and febuxostat, have certain limitations. For example, allopurinol can inhibit uric acid synthesis and simultaneously cause adverse reactions such as liver and kidney injury, allergy, bone marrow transplantation and the like. Febuxostat can specifically inhibit reduced and oxidized xanthine oxidase, and compared with allopurinol, febuxostat has higher safety, but has adverse reactions such as liver dysfunction, gastrointestinal reaction, arthralgia and the like in clinical application. The medicines for promoting uric acid excretion include probenecid, tribromouron, etc., and mainly act on urate transporter of renal proximal tubular to inhibit uric acid reabsorption. However, researches show that probenecid and benzbromarone have gastrointestinal reactions and cause side effects such as acute attacks of renal colic and gout. Therefore, the searching of the natural active ingredients with the hyperuricemia reducing effect from natural products with high safety, wide sources and rich varieties has important social and economic significance for preventing and treating hyperuricemia.

The active ingredients of the natural products have two main mechanisms of action for resisting hyperuricemia, namely, important enzymes affecting purine metabolism and inhibiting uric acid generation; secondly, uric acid excretion of kidneys is promoted by regulating and controlling urate transporter. Oxidase inhibitors targeting xanthine oxidase can bind to the active site (Mo-pt) of the enzyme, directly blocking uric acid production. The renal tubule uric acid transporter inhibitor mainly acts on a urate anion transporter, an organic anion transporter and an organic cation transporter, and increases uric acid excretion.

Brown algae contains not only active polysaccharide known to those skilled in the art such as algin and fucoidan, but also a part of polysaccharide polymer mainly composed of uronic acid in the cell wall, which is difficult to extract and has been neglected until now. The prior art CN103539863B (application of low sulfated heteroglycan which is derived from brown algae and is rich in glucuronic acid in preparing medicaments and health care products for treating parkinsonism) is extracted from brown algae and separated by anion exchange chromatography to obtain the low sulfated heteroglycan which is rich in glucuronic acid, but the low sulfated heteroglycan has complex composition and still contains a considerable amount of fucose, and the uronic acid content is not half. The prior art discloses very limited information on other uronic acid rich polysaccharide components, in particular fucoidin free polysaccharides, in the cell wall of brown algae.

Polysaccharides have a variety of activities, and the structural composition affects their biological activity. And to date, there is no simple preparation method of polysaccharide mainly comprising uronic acid and not containing fucose, and application of polysaccharide in medicines and foods for reducing uric acid or treating hyperuricemia or gout.

Disclosure of Invention

In order to solve the problems, the invention provides brown algae heteropolysaccharide and application thereof. The brown algae heteropolysaccharide with high uronic acid content and no fucose is obtained by the limited preparation method. The brown algae heteropolysaccharide provided can inhibit xanthine oxidase, thereby reducing uric acid synthesis, and can promote uric acid excretion, reduce uric acid absorption and play a role in reducing uric acid by regulating the expression of uric acid transport related proteins.

In order to achieve the above purpose, the present invention provides the following technical solutions:

one of the technical schemes of the invention is as follows: providing brown algae heteropolysaccharide, which comprises the following components in percentage by mass: 30-90% of polyglucuronic acid, 1-70% of heterozygous mannuronate and 0.1-30% of low-sulfation heterozygous glucan; the total mass fraction of polyglucuronic acid, heterozygous mannuronate and low-sulfation heterozygous glucan is not less than 90%; the brown algae heteropolysaccharide does not contain fucose;

the extraction steps of the brown algae heteropolysaccharide comprise:

pulverizing brown algae, extracting with water or dilute hydrochloric acid, adding the residue into sodium acetate water solution, heating for extraction, adding alcohol into the extractive solution, standing, precipitating, redissolving, and dialyzing to obtain brown algae heteropolysaccharide.

The dilute hydrochloric acid is hydrochloric acid solution with mass fraction not higher than 20%.

According to the invention, the sodium acetate aqueous solution is selected as the extracting solution, so that the dissolution of uronic acid can be promoted and the dissolution of fucose can be inhibited in the extracting process, thereby preparing the fucoidin with high uronic acid content and without fucose; and further removing the added sodium acetate by dialysis to obtain the high-purity brown algae heteropolysaccharide.

The brown algae used in the invention can select the residual brown algae residue in the food industry and industry, and provides a high-value utilization mode for the brown algae residue.

Preferably, the water adding extraction is carried out by adding water according to a feed liquid ratio of 1g to 20-30 mL at 100-120 ℃ for 1-2 h or adding water according to a feed liquid ratio of 1g to 20-30 mL at normal temperature for overnight; the dilute hydrochloric acid is added to the mixture according to the ratio of 1g to 20-30 mL of the mixture to be extracted, and the mixture is stirred for 3-4 hours or is ultrasonically treated for 2-3 hours at normal temperature. The main purposes are as follows: the fucoidan sulfate component containing fucose is primarily discarded.

Preferably, the mass fraction of sodium acetate in the sodium acetate aqueous solution is 3-5%.

Preferably, the temperature of the heating extraction is 100-120 ℃, the time is 1-3 hours, and the extraction times are 1-3 times.

Preferably, the alcohol is ethanol, and the addition amount is 3-4 times of the volume of the extracting solution.

Preferably, the molecular weight cut-off of the dialysis bag used for dialysis is 3000-4000 Da, more preferably 3500Da.

Preferably, the content of polyglucuronate in the brown algae heteropolysaccharide is 40-85wt%, the content of heterozygous mannuronate is 5-60wt% and the content of low-sulfation heterozygous dextran is 0.5-25wt%; more preferably, 45-80 wt.% polyglucuronic acid, 10-50 wt.% hybrid mannuronate and 1-20 wt.% low-sulfated hybrid glucan; most preferred are 55 to 68wt.% polyglucuronic acid, 22.7 to 45wt.% hybrid mannuronate and 2 to 12wt.% low sulfated hybrid glucan.

Preferably, the components of the polyglucuronic acid include any one or more of glucuronic acid tetrasaccharide, pentasaccharide, hexasaccharide, heptasaccharide, octasaccharide, nonasaccharide, decasaccharide, undecane saccharide, dodecasaccharide, tridecanose, tetradecane saccharide, pentadecanose, hexadecane saccharide, heptadecanose, octadecanose, nonadecanose and icosane; the structure of the polyglucuronic acid includes (GlcA) _x Wherein x is the degree of polymerization of GlcA and the value is any integer from 4 to 20.

Preferably, the components of the hybrid mannuronic acid include any one or more of mannuronic acid tetrasaccharide, pentasaccharide, hexasaccharide, heptasaccharide, octasaccharide, nonasaccharide, decasaccharide, undecane saccharide, dodecasaccharide, tridecane, tetradecane saccharide, pentasaccharide, hexadecane saccharide, heptasaccharide, octadecane saccharide, nonasaccharide and icose; the structure of the hybrid mannuronate includes (GlcA) _x (Man) _y Wherein x is the degree of polymerization of GlcA, the value is any integer from 2 to 10, y is the degree of polymerization of Man, and the value is any integer from 2 to 10.

Preferably, the components of the low sulfated heterozygous glucan include any one or more of sulfated heterozygous glucan xylotetraose, pentasaccharide, hexasaccharide, heptasaccharide, octasaccharide, nonasaccharide, decasaccharide, undecanose, dodecasaccharide, tridecanose, tetradecanose, pentadecanose, hexadecanose, heptadecanose, octadecanose, nonadecanose and icosane; the structure of the low-sulfated hybrid glucan comprises (Glc) _x (Xyl) _z S _n Wherein x is the polymerization degree of GlcA, the value is any integer from 2 to 10, z is the polymerization degree of Xyl, the value is any integer from 2 to 10, n is the substitution number of sulfuric acid groups, the value is any integer from 1 to 10, and the substitution position of the sulfuric acid groups is at the C2 position, the C3 position or the C4 position of xylose.

The second technical scheme of the invention is as follows: provides an application of the brown algae heteropolysaccharide in preparing preparations for inhibiting xanthine oxidase activity.

The third technical scheme of the invention: provides an application of the brown algae heteropolysaccharide in preparing uric acid activity reducing preparations.

The fourth technical scheme of the invention: provides an application of the brown algae heteropolysaccharide in preparing medicines or foods for reducing uric acid, preventing hyperuricemia, treating hyperuricemia, preventing gout or treating gout.

The invention can prepare the medicament or food into various dosage forms known in the field according to actual needs, such as tablets, capsules, pills, granules and the like in solid preparations, injections, solutions and the like in liquid preparations, gels in semisolid preparations, aerosols, sprays and the like in gas preparations. Alternatively, the food product may be prepared in a variety well known in the art, such as biscuits, bread, various ready-to-eat products, etc., according to actual needs.

It is also understood by those skilled in the art that when preparing the medicine or food for reducing uric acid, preventing hyperuricemia, treating hyperuricemia, preventing gout or treating gout by using the brown algae heteropolysaccharide of the present invention as a main active ingredient, conventional auxiliary agents such as excipient, filler, disintegrating agent, cosolvent, lubricant, adhesive, taste masking agent, skeleton material, coating material, colorant, etc. may be added according to actual needs.

The beneficial technical effects of the invention are as follows:

the brown algae heteropolysaccharide with specific component content is obtained by limiting the extraction steps, and has the functions of reducing uric acid, improving renal function and resisting inflammation for hyperuricemia and acute gouty arthritis. Can be used for preparing medicines, functional foods or health care products for preventing and treating hyperuricemia, gout and gouty arthritis.

Drawings

FIG. 1 shows the brown seaweed heteropolysaccharide P1 obtained in example 1 ¹³ C-NMR spectrum.

Fig. 2 is a partial enlarged view of fig. 1.

FIG. 3 is a mass spectrum of characteristics of polyglucuronic acid components and hybrid mannuronic acid components.

FIG. 4 is a characteristic mass spectrum of the low-sulfated hybrid glucan component.

FIG. 5 shows the inhibition of xanthine oxidase by Fuc of comparative example 2, P1-P5 of brown algae heteropolysaccharide prepared in examples 1-5, and P6 prepared in comparative example 1.

FIG. 6 shows uric acid levels of mice treated with Fuc of comparative example 2 and P1-P5 of Fuc prepared in examples 1-5, and P6 prepared in comparative example 1.

FIG. 7 shows the effect of Fuc on serum creatinine and blood urea nitrogen expression in mice with hyperuricic models, including Fuc prepared in examples 1-5, P1-P5 prepared in comparative example 1, and comparative example 2.

FIG. 8 shows the effect of Fuc of comparative example 2 and P1-P5 of Fuc of comparative example 1 and P6 of Fuc of example 1 on xanthine oxidase and adenosine deaminase in liver of mice with hyperuricic acid model.

FIG. 9 shows the kidney protecting effect of Fuc of comparative example 2 and P1-P5 of Fuc of comparative example 1 and P6 of Fuc of example 1 on mice with hyperuricemia model.

FIG. 10 shows the effect of fucoidan P1 and P3 prepared in examples 1 and 3 on inflammatory factor expression in rats with acute gouty arthritis.

FIG. 11 shows the effect of fucoidan P1 and P3 prepared in examples 1 and 3 on uric acid, xanthine oxidase, creatinine and urea nitrogen in blood of rats with acute gouty arthritis.

Detailed Description

Various exemplary embodiments of the invention will now be described in detail, which should not be considered as limiting the invention, but rather as more detailed descriptions of certain aspects, features and embodiments of the invention. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

In addition, for numerical ranges in this disclosure, it is understood that each intermediate value between the upper and lower limits of the ranges is also specifically disclosed. Every smaller range between any stated value or stated range, and any other stated value or intermediate value within the stated range, is also encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention.

As used herein, the terms "comprising," "including," "having," "containing," and the like are intended to be inclusive and mean an inclusion, but not limited to.

Example 1

Preparation of kelp-derived heteropolysaccharide

Dicing dry kelp, weighing 100g, adding into 3000mL of water, extracting at 100 ℃ for 1.5h, filtering, adding 3L of 4.5wt.% sodium acetate solution into the residue, stirring and extracting at 100 ℃ for 2h, filtering out kelp residue, repeating the extraction, performing solid-liquid separation to obtain kelp residue, adding 2L of 4.5wt.% sodium acetate solution again, stirring and extracting at 100 ℃ for 2h, and obtaining an extract, wherein the extract is free of fucose by detecting by an L-cysteine hydrochloride method. Mixing the extractive solutions of the sodium acetate solutions, adding edible ethanol with volume 3 times of that of the extractive solution, standing for precipitating with ethanol overnight, centrifuging to obtain precipitate, dissolving again, dialyzing with 3500Da dialysis bag, and drying to obtain 0.58g laminarin P1.

Example 2

Preparation of gulfweed-derived heteropolysaccharide

Cutting dry gulfweed into small segments, weighing 100g, adding into 3000mL of water, extracting for 1.5h at 100 ℃, filtering, adding 4.5wt.% sodium acetate solution 3L into residues, stirring and extracting for 2h at 100 ℃, filtering out algae residues from the extracting solution, repeating the extraction to obtain gulfweed residues, washing with cold water, adding 4.5wt.% sodium acetate solution 2L again, stirring and extracting for 2h at 100 ℃, and obtaining an extracting solution. Mixing the extractive solutions of sodium acetate solutions, adding edible ethanol with volume of 4 times, standing for precipitating with ethanol overnight, centrifuging to obtain precipitate, dissolving again, dialyzing with 3500Da dialysis bag, and drying to obtain 1.12g Sargassum heteropolysaccharide P2.

Example 3

Preparation of heteropolysaccharide from sargassum pallidum

The dried sargassum pallidum is cut into small segments, 100g of the sargassum pallidum is weighed and added with 2L of 0.1M HCl, and the mixture is stirred and extracted for 3 hours at room temperature. Filtering to obtain algae residue, adding 4.5wt.% sodium acetate solution 2L, stirring at 100deg.C, extracting for 2 hr, and filtering to obtain algae residue. Adding 2L of 4.5wt.% sodium acetate solution again, stirring and extracting for 2 hours at 100 ℃, repeatedly extracting for 1 time, combining sodium acetate solution extracting solutions, adding 3 times of edible ethanol into the extracting solutions, standing for alcohol precipitation overnight, centrifuging to obtain precipitate, re-dissolving the precipitate, dialyzing by using 3500Da dialysis bags, and drying to obtain 1.05g of sargassum pallidum heteropolysaccharide P3.

Example 4

Preparation of laminaria japonica residue source heteropolysaccharide

100g of kelp residue obtained after the extraction of fucoidan sulfate is obtained from the company limited by the pharmaceutical industry of June, henan, jilin, is weighed, 2L of water is added for overnight, the kelp residue is obtained by filtering, 4.5wt.% of sodium acetate solution is added to the residue, 2L of sodium acetate solution is stirred and extracted for 2 hours at 100 ℃, 4.5wt.% of sodium acetate solution is added again, 2L of sodium acetate solution is added again, stirring and extraction are carried out for 2 hours at 100 ℃,1 time of repeated extraction is carried out, then the sodium acetate solution extract is combined, 3 times of volume of edible ethanol is added to the extract, after standing for alcohol precipitation, the precipitate is centrifugally taken, the precipitate is redissolved, dialysis is carried out by using 3500Da dialysis bag, and 0.64g of kelp heteropolysaccharide P4 is obtained after drying.

Example 5

Preparation of Ascophyllum nodosum heteropolysaccharide

The dried foam was She Zaoqie pieces, 100g was weighed and added to 2L of 0.1M HCl and extracted ultrasonically at room temperature for 2 hours. After washing the algae residue with water, filtering, adding 2L of 4.5wt.% sodium acetate solution, stirring at 100deg.C for 3 hr, filtering to obtain algae residue, adding 2L of 4.5wt.% sodium acetate solution, stirring at 100deg.C for 1 hr, repeating the extraction for 1 time, and mixing the sodium acetate solution extracts. Adding 4 times of edible ethanol into the extracting solution, standing for alcohol precipitation overnight, centrifuging to obtain precipitate, re-dissolving the precipitate, dialyzing with 3500Da dialysis bag, and drying to obtain 0.85g of Ascophyllum nodosum heteropolysaccharide P5.

Comparative example 1

Preparation of kelp-derived heteropolysaccharide

Compared to example 1, laminarin P6 was produced by replacing 4.5wt.% sodium acetate solution with an equal volume of distilled water.

Comparative example 2

In the past, the research reports that fucoidan (Fucodian) has a certain uric acid reducing effect, and in order to verify the effect of different brown algae-derived sulfuric acid heteropolysaccharide in the invention, the invention compares commercial sigma companies from Fucus vesiculosus @, which is a natural source of fucoidanFucus vesiculosus) Fucoidan (Sigma-Aldrich, steinheim, germany). The structural main chains are mainly (1.fwdarw.3) and (1.fwdarw.4) connected alternately, and the sulfate group is mainly located at the C-2 or C-4 position of alpha-L-fucose (Patankar et al, 1993). In the present invention, the commercial Fucoidan, abbreviated as Fuc, was used as a comparative experimental sample to conduct comparative studies on the in vitro and in vivo activities of P1-P5.

Example 6

Physicochemical property analysis of brown algae heteropolysaccharide

As described previously, brown algae heteropolysaccharide was obtained from different brown algae, 5mg of water was prepared as a polysaccharide solution of 5mg/mL, and the molecular weight distribution was analyzed by HPGPC after 0.22 μm filtration.

Drawing standard curves by adopting serial dextran standards with molecular weights of 2700, 5250, 9750, 36800, 64650, 135350 and 300600 Da, and correcting curve fitting to obtain f (x) = -0.3172163x+9.026462, R ² = 0.9992. The weight average molecular weight (Mw), number average molecular weight (Mn) and dispersion coefficient PDI (Mw/Mn) of the 5 brown seaweed hetero polysaccharides are shown in Table 1. It can be seen that the molecular weight of the heteropolysaccharide is around 20 kD.

The method comprises the steps of measuring the content of uronic acid by a carbazole colorimetric method by taking glucuronic acid as a standard substance, measuring the content of fucose by a cysteine hydrochloride method by taking fucose as a standard substance, measuring the content of total sugar by a phenol sulfuric acid method by taking mannose as a standard substance, and measuring the content of sulfuric acid groups by an ion chromatographic method by drawing standard curves by taking potassium sulfate with different concentrations as standard substances. The results of physicochemical property analysis of 5 example brown algae heteropolysaccharides and 1 comparative example polysaccharide are shown in Table 1. Our results show that there is no significant difference in chemical composition of heteropolysaccharide extracted from different brown algae. No fucose content was detected in the different brown algae heteropolysaccharides; the uronic acid content is more than 55% of the heteropolysaccharide, and the heteropolysaccharide also contains a small amount of sulfuric acid groups, which are 4.60% -15.25%. Whereas the comparative polysaccharide P6 is typically fucoidan sulfate, there is a considerable amount of fucose and a large amount of sulfate groups.

The monosaccharide composition of the brown seaweed heteropolysaccharide was analyzed by HPLC-PMP pre-column derivatization. Respectively precisely weighing 10-20mg of sample to be measured, adding 1 mL water for dissolution, adding 1 mL of 4M trifluoroacetic acid, hydrolyzing at 105 ℃ for 4 hours, neutralizing the hydrolyzed solution, and fixing the volume to 10 mL.

And carrying out HPLC analysis on the hydrolysis liquid of the sample to be detected and the mixed monosaccharide standard substance after the hydrolysis liquid and the mixed monosaccharide standard substance are respectively derived by PMP. Adopting Shimadzu LC-20 high performance liquid chromatography; the chromatographic column is ZORBAX SB-AQ C18 column (4.6 mm ×250 mm, 5 μm), column temperature box is 30deg.C, detector is PDA detector, mobile phase ratio: 0.1 mol/L PBS (pH 6.8) acetonitrile=83:17 (v/v,%) binary gradient elution was carried out at a flow rate of 0.8 mL/min, 20. Mu.L of each sample to be tested was loaded, and the acquisition time was 60 minutes. The neutral monosaccharide composition of 5 brown algae heteropolysaccharides is shown in Table 2, and our results show that the heteropolysaccharides mainly comprising glucuronic acid can be obtained from various brown algae by the preparation method, and the composition ratio of mannose to glucuronic acid is about 1:1-1:2. In addition, the heteropolysaccharide also contains a small amount of xylose and glucose, and no fucose and other monosaccharides are detected, which indicates that the monosaccharide composition of the heteropolysaccharide is glucuronic acid, mannose, xylose and glucose. The monosaccharide composition is mainly fucose, and the molar ratio is that of fucose, which is obviously different from the comparative example polysaccharide P6: mannose: glucuronic acid: glucose: xylose = 1:0.56:0.23:0.20:0.10.

TABLE 1 physicochemical Property analysis results of brown algae heteropolysaccharide

Note that: nd-undetected.

TABLE 2 monosaccharide composition molar ratio of brown algae heteropolysaccharide

Example 7

Methylation analysis of sugar residue connection mode of brown algae heteropolysaccharide

Dissolving each heteropolysaccharide sample 50, mg in 5, mL deionized water, passing through hydrogen form 732 ^# The cation exchange resin is used for replacing heteropolysaccharide samples into hydrogen forms respectively and then freeze-drying. Uronic acid reduction of heteropolysaccharide: 30mg of the hydrogen-form heteropolysaccharide sample was weighed and dissolved in 15. 15 mL of a 0.1M aqueous solution of 2-morpholinoethanesulfonic acid (MES) containing THF (75%, v/v), and after the pH of the sample solution was adjusted to 4.75 with 10% aqueous triethylamine, 120 mg of EDC was added, and the reaction was stirred at room temperature for 1 hour and then at 50℃for 1 hour, during which time two 12. 12 mL portions of 2M sodium borohydride solution were added. After the reaction is finished, boric acid is removed by dialysis rotary evaporation, and the reduced heteropolysaccharide is freeze-dried.

And (3) desulfurizing heteropolysaccharide: taking reduced heteropolysaccharide 20mg, desulfurizing by using dimethyl sulfoxide-methanol solution (10 mL,9:1, v/v), stopping the reaction after 5 hours at 80 ℃, adding deionized water, regulating the pH of the reaction solution to 9 by pyridine, and dialyzing and freeze-drying to obtain reduced and desulfurized heteropolysaccharide.

Methylation reaction: drying the reduced and desulfurized heteropolysaccharide in a vacuum drying oven for 24 hours, ultrasonically dissolving the heteropolysaccharide by using 2 mL dehydrated dimethyl sulfoxide, adding 2 mL freshly prepared dimethyl sulfoxide sodium reagent, stirring at room temperature overnight, dropwise adding 2 mL methyl iodide twice, stirring at room temperature, reacting until the reaction liquid is clear and light pink, adding water, stopping the reaction, and extracting with chloroform to obtain a methylated product.

Hydrolysis, reduction and acetylation: and (3) respectively drying the methylated products, hydrolyzing the products into monosaccharides by using trifluoroacetic acid, reducing the monosaccharides by using sodium borodeuteride-sodium hydroxide solution, and finally performing an acetylation reaction, and performing GC-MS analysis on the chloroform extraction layer.

GC-MS analysis conditions: agilent HP-5MS gas chromatography column (30 m X250 μm X0.25 μm), temperature programmed process: the initial temperature of 170 ℃ was maintained for 2 minutes, and the temperature was raised to 300 ℃ at a rate of 2.5 ℃ per minute, followed by 10 minutes and analysis time of 60 minutes.

The types of sugar residues, the connection modes and the molar ratios of 5 brown algae heteropolysaccharides are obtained by comparison with a PMAA database of CRCC, and are shown in Table 3. There have been reported (Liu Lili, zhang Yuqian, han Xianwei, etc.. An improvement of the method for reducing uronic acid in acidic polysaccharides [ J ]. Chinese ocean medicine, 2014,33 (4): 1-7.), because the heteropolysaccharide contains a large amount of glucuronic acid, it is not directly dissolved in the methylating agent, resulting in extremely insufficient methylation reaction, and the uronic acid needs to be reduced before methylation analysis. Based on this, glucuronic acid in different brown seaweed heteropolysaccharides is fully reduced to glucose, and methylation analysis results show that 9 types of sugar residues are detected in the heteropolysaccharide, and monosaccharide types are consistent with the analysis results of HPLC-PMP pre-column derivatization method. As a result, the uronic acid in the heteropolysaccharide was mainly 1.fwdarw.4 linked, followed by 1.fwdarw.3 linked and a small number of 1.fwdarw.3, 4 branched linkages; the heteropolysaccharide also contains a large amount of mannose, and is connected in a way of 1-2; xylose is connected in the modes of 1-3 and 1-4. No → 3) -Xyl residues were detected due to the lower xylose content in P2 and P5. The results of monosaccharide analysis tell us that the heteropolysaccharide itself also contains a small amount of glucose, but the reduced heteropolysaccharide cannot distinguish the glucose content of the heteropolysaccharide, so that based on the molar ratio of residues in the methylation result, we can calculate the ratio of different monosaccharide compositions, which is substantially identical to the result in example 6. The monosaccharide composition as P1 was calculated as (glca+glc): man: xyl= (0.25+1.00+0.14+0.08): (0.12+0.75): (0.11+. 0.02+0.05) =1.47:0.67:0.18, i.e. 1:0.59:0.12. Similarly, (GlcA+Glc) Man: xyl of P2, P3, P4, P5 are 1:0.50:0.16, 1:0.47:0.04, 1:0.82:0.26, 1:0.58:0.04, respectively.

Table 35 methylation analysis results of brown algae heteropolysaccharide

Note that: nd-undetected.

Example 8

Stepwise acid hydrolysis of brown algae heteropolysaccharide and "Bottom-Up" strategy structural analysis

Because the structure composition of the heteropolysaccharide is complex and the connection mode is diversified, in order to analyze the complete structure, the polysaccharide structure is hydrolyzed layer by adopting progressive acid hydrolysis, monosaccharide composition analysis is respectively carried out on different segments, and then the structure information of the segments is spliced together through a 'Bottom-Up' strategy, so that the complete polysaccharide structure is obtained.

Step-by-step acid hydrolysis: respectively weighing 50 parts of each mg parts of each 50 parts of brown algae heteropolysaccharide P1 and P4, respectively dissolving in 0.5M, 1M, 2M and 4M trifluoroacetic acid of 5 mL, sealing, and hydrolyzing at 105deg.C for 1 hr. After the reaction is finished, the reaction solution is filled into a 3.5kD dialysis bag and dialyzed by deionized water, and after the solution in the bag is concentrated by rotary evaporation, monosaccharide composition analysis is carried out. After P1 is hydrolyzed by 0.5M trifluoroacetic acid, 1M trifluoroacetic acid, 2M trifluoroacetic acid and 4M trifluoroacetic acid, the components obtained by dialysis are named as P1-1, P1-2, P1-3 and P1-4; after P4 is hydrolyzed by 0.5M trifluoroacetic acid, 1M trifluoroacetic acid, 2M trifluoroacetic acid and 4M trifluoroacetic acid, the components obtained by dialysis are named as P4-1, P4-2, P4-3 and P4-4.

The results are shown in Table 4. In an acidic environment with low concentration, the branched chain fragments of the polysaccharide are firstly hydrolyzed, and the main chain structure of the polysaccharide is gradually destroyed along with the increase of the acidic concentration. By progressive acid hydrolysis, the proportion of xylose and glucose in the monosaccharide composition of the hydrolysis product is simultaneously and rapidly reduced along with the increase of the acid concentration, which shows that the xylose and the glucose in the heteropolysaccharide are connected together and are connected to the main chain in a branched manner; after the concentration of trifluoroacetic acid was increased to 2M, the ratio of glucuronic acid to mannose remained essentially unchanged, indicating that the heteropolysaccharide backbone structure consisted of glucuronic acid and mannose; as hydrolysis proceeds, the mannose ratio does not decrease, indicating the absence of a mannooligosaccharide junction fragment; the ratio of glucuronic acid to mannose is maintained at 1:1-1:2, which indicates that mannose and glucuronic acid are mutually connected to form mannuronic acid components or glucose is connected to form polyglucuronic acid components.

TABLE 4 molar composition of monosaccharides by progressive acid hydrolysis of brown algae heteropolysaccharide

Example 9

Kelp-derived heteropolysaccharide P1 ¹³ C-NMR spectra

Weighing about 30mg of P1, replacing with deuterium water for 3 times, dissolving again in a certain amount of deuterium water, loading into a nuclear magnetic tube, adding 2 drops of deuterated acetone (reference chemical shift value 29.84), and performing ¹³ The signal accumulation time was 26 hours in the C-NMR spectrum analysis.

P1 ¹³ The C-NMR spectrum is shown in FIG. 1, and FIG. 2 is a partial enlarged view of FIG. 1. The structure of the P1 is characterized by a one-dimensional nuclear magnetic carbon spectrum, so that the composition condition of the main component of the P1 can be clearly observed. The peak of the anomeric carbon signal of a large amount of glucuronic acid and a small amount of xylose is near 110ppm, the peak of the anomeric carbon signal of alpha-Man is near 100ppm, and the chemical shift of uronic acid C6 is between 170 and 180 ppm, and because glucuronic acid in P1 has various connection modes and is connected with different sugar residues, the chemical shift is generated. According to the literature reportMar. Drugs 2018, 16, 291；Carbohydrate Polymers, 2016, 146, 238-244) Signals of 170-175 ppmThe peak is mainly the glucuronic acid C6 peak in the hybrid mannuronic acid component, and the signal peak between 175 ppm and 180 ppm is mainly the glucuronic acid C6 peak of the polyglucuronic acid component. In one-dimensional nuclear magnetic carbon spectra, the signal intensity of carbon may represent the relative number of carbons. The ratio of polyglucuronic acid component to heterozygous mannuronic acid component was calculated to be 1:0.50, consistent with the results described above.

Example 10

Mass spectrometry analysis of brown algae heteropolysaccharide P1

To further clarify the different components contained in the heteropolysaccharide, mass spectrometry was performed on the P1-3 components obtained by stepwise acid hydrolysis of P1. 100 mg of P1-3 was dissolved in deionized water, and a certain amount of concentrated sulfuric acid was added so that the final concentration of the concentrated sulfuric acid was 0.5. 0.5M, the total volume was 8 mL, and the mixture was heated at 80℃for 3 hours, then neutralized with barium hydroxide, centrifuged to remove salt, and the degradation solution was concentrated by spin evaporation, and after freeze-drying, electrospray mass spectrometry (ESI-MS) analysis was performed, and the result was shown in FIG. 3.

Collecting the solution outside the dialysis bag when P1 is hydrolyzed by acid to prepare P1-1 and P1-2, concentrating by rotary evaporation, and adopting HyperSep ^TM Hypercarb ^TM The ESI-MS test was performed after desalting the SPE cartridge (from Siemens, 60106-302) and the results are shown in FIG. 4.

ESI-MS analysis parameter set:

sample loading speed 5 mu L/min

Capillary voltage 3KV

Collision voltage 200V

Ion source temperature 120 DEG C

The volatilization temperature of the solvent is 350 DEG C

Air flow rate 10L/min

Data acquisition mode Full scan

Mass-to-charge ratio range m/z=150 to 1500

Collection mode anion mode

FIG. 3 shows characteristic mass spectra of polyglucuronic acid components and hybrid mannuronic acid components, wherein a number of characteristic peaks of (GlcA) x and (GlcA) x (Man) y occur. The analysis of FIG. 3 is shown in Table 5.

FIG. 4 shows a characteristic mass spectrum of a low sulfated hybrid glucan component in which a number of (Xyl) zSn, (Glc) x (Xyl) zSn characteristic peaks can be seen, and no (Glc) xSn peak appears, indicating that the sulfate substitution site is present on the Xyl sugar ring and no sulfate substitution is present on the Glc sugar ring. The low sulfated hybrid glucan component was less abundant in the heteropolysaccharide, as confirmed by mass spectrometry results, since the polymerization degree of the produced glucan fragments was low. The analysis of FIG. 4 is shown in Table 6.

TABLE 5 analysis results of characteristic mass spectra of polyglucuronic acid component and hybrid mannuronic acid component

TABLE 6 analysis of characteristic mass spectra of Low-sulfated hybrid Glucoxylan Components

From the NMR and ESI-MS analysis results and the methylation and progressive acid hydrolysis results, it can be seen that the main chain structure of fucoidin P1 is mainly composed of glucuronic acid and mannose, and contains two kinds of hybrid mannuronate main chains, namely glucuronic acid and mannose which are mutually connected, and polyglucuronate main chains, wherein glucuronic acid is mutually connected; the branched chain is mainly sulfated xylose and glucose, and the branched chain has a smaller polymerization degree. That is, the structural components of the obtained brown algae heteropolysaccharide are: a polyglucuronic acid component (not less than 50%), a hybrid mannuronic acid component (not more than 50% and not less than half of the polyglucuronic acid component), and a low-sulfated hybrid glucan component (not more than 15%).

The uric acid-reducing efficacy of the heteropolysaccharides P1-P5 is demonstrated by experiments

Example 11

In vitro xanthine oxidase inhibition Activity assay

Setting an experimental group: xanthine + xanthine oxidase + P1 (concentration of 2mg/mL,1mg/mL,0.5mg/mL,0.25mg/mL,0.125 mg/mL); xanthine + xanthine oxidase + P2 (concentration of 2mg/mL,1mg/mL,0.5mg/mL,0.25mg/mL,0.125 mg/mL); xanthine + xanthine oxidase + P3 (concentration of 2mg/mL,1mg/mL,0.5mg/mL,0.25mg/mL,0.125 mg/mL); xanthine + xanthine oxidase + P4 (concentration of 2mg/mL,1mg/mL,0.5mg/mL,0.25mg/mL,0.125 mg/mL); xanthine + xanthine oxidase + P5 (concentration of 2mg/mL,1mg/mL,0.5mg/mL,0.25mg/mL,0.125 mg/mL); xanthine + xanthine oxidase + P6 (concentration of 2mg/mL,1mg/mL,0.5mg/mL,0.25mg/mL,0.125 mg/mL); xanthine + xanthine oxidase + Fuc (concentration of 2mg/mL,1mg/mL,0.5mg/mL,0.25mg/mL,0.125 mg/mL); blank group: xanthine + phosphate buffer;

positive control group of xanthine + xanthine oxidase;

uric acid has light absorption at 294nm, and the amount of uric acid production is detected by an enzyme-labeled instrument.

The increase of the absorbance value of each experimental group in unit time is smaller than that of the positive control group, and the increase of uric acid of each experimental group is smaller than that of the positive control group, which indicates that the catalytic activity of xanthine oxidase is inhibited, and the samples P1, P2, P3, P4 and P5 are proved to have obvious inhibition activity on xanthine oxidase, and the activity is superior to that of P6 and Fuc. And calculating the inhibition rate of xanthine oxidase according to the scanning result of the enzyme labeling instrument, wherein the calculation formula is as follows:

inhibition (%) =1- (Δod experimental group)/(Δod positive control group), Δod is the absorbance change value at each group 294 nm. The results obtained are shown in FIG. 5.

Example 12

Effects of fucoidin P1-P5 on hyperuricemia induced by Yeast extract and potassium oxazinate.

Establishment of hyperuricemia model mice: healthy male Kunqian mice, 100, of 5-6 weeks of age, were randomly divided into 10 groups of 18-20g body weight, each: normal control group, model control group, positive control group (benzbromarone group) and P1-P6, fuc administration group. After the adaptation period is finished, starting to induce a hyperuricemia model, firstly, performing gastric lavage by using yeast powder (20 g/kg) in a model control group, a P1-P6 Fuc treatment group and a positive control medicine group, and performing gastric lavage by using normal control group by using an equivalent amount of physiological saline; each mouse was intraperitoneally injected with potassium oxazinate (450 mg/kg) after gavage, except for normal control mice. The mice were weighed every 3 days and recorded for weight change for 14 consecutive days. Uric acid levels of mice were tested on day 14. Detecting the rise of uric acid value, and determining that the high uric acid mice are successfully modeled. On day 15, the mice of the administration group were given respective P1-P5 mg/kg by gavage, 10mg/kg of benzbromarone was given by gavage to each of the mice of the positive control group, and the normal control group was given an equivalent amount of 0.5% CMC-Na by gavage. The intraperitoneal injection of potassium oxazinate (450 mg/kg) was continued during the drug treatment. After 7 days of continuous administration, mice were taken venous blood to detect blood uric acid levels. Mice were then sacrificed under anesthesia and hearts were bled. The resulting blood was allowed to stand at room temperature for 1 hour, centrifuged at 3500r for 5min, and the supernatant was retained to obtain serum. Serum uric acid levels, liver function enzymes (ALT, AST) and levels of kidney function enzymes (blood urea nitrogen, creatinine) were measured using a fully automated biochemical analyzer. The liver and kidney of the mice were removed and washed with PBS solution and the filter paper was blotted dry. One side of kidney and one liver are placed in paraformaldehyde for tissue morphology detection, the other side of kidney and 50mg of liver tissue are placed on ice for homogenization, and tissue RNA and protein are extracted and then stored at-80 ℃.

The research on the influence of the fucoidan P1-P6 on the uric acid level of mice with hyperuricemia induced by yeast extract and potassium oxazinate shows that the uric acid level of mice in a model group is obviously increased, and the blood uric acid level of the mice in the two groups is obviously reduced relative to that of the mice in the model group after P1-P5 and phenylbromarone are given for one week, and the effect is superior to that of P6 and Fuc. Wherein the blood uric acid level of the mice in the P1-P5 treatment group is lower than that of the positive control drug benzbromarone group, as shown in figure 6. It is shown that each of P1-P5 has a remarkable effect of reducing blood uric acid, and the effect is superior to that of comparative examples P6 and Fuc.

Example 13

Action of changes in levels of renal function enzymes (creatinine, blood urea nitrogen)

Serum from mice was taken and the serum levels of creatinine and blood urea nitrogen were measured in each group of mice using a whole blood analyzer, and the results are shown in FIG. 7. Compared with the expression level P1-P5 of creatinine and blood urea nitrogen in mice treated by the hyperuricemia model, the expression level of creatinine and blood urea nitrogen in serum of mice treated by the hyperuricemia model is obviously reduced, and the effect of the serum is equivalent to that of a positive control drug, namely benzbromarone, wherein the effect of P1 and P2 is slightly better than that of benzbromarone. The P1-P5 groups all perform better than the P6 and Fuc treatment groups. It is demonstrated that P1-P5 can significantly improve kidney function in hyperuricemia mice.

Example 14

Effect of P1-P5 heteropolysaccharide on mouse liver xanthine oxidase and adenosine deaminase.

Xanthine oxidase is a key enzyme for promoting liver anabolism. Xanthine oxidase catalyzes the oxidation of hypoxanthine to xanthine and is in turn a catalytic enzyme for the oxidation of xanthine to uric acid. Xanthine oxidase plays an important role in the catabolism of purines in organisms. The experimental result shows that: xanthine oxidase activity was significantly increased in the livers of mice in the model group compared to the control group. Compared with the mice in the model group, the activity of xanthine oxidase in the livers of the mice in the positive control drug (benzbromarone, BENZ) group and the P1-P5 treatment group is obviously reduced, and the effect is superior to that of the mice in the P6 and Fuc treatment groups. The results are shown in FIG. 8.

Example 15

Protection of hyperuricemia induced renal injury by heteropolysaccharide P1-P5

Long-term hyperuricemia causes crystalline deposition of uric acid in the kidneys and inflammation of the kidneys. The kidney tubule is deformed; as shown in fig. 9, in the kidney of the hyperuricemia model mouse, the gap between the kidney tissues is enlarged, and the hollow space appears around the tubular, which indicates that the kidney tissues are damaged. After the P1-P5 heteropolysaccharide is administrated, the kidney tissue of the mice with high uric acid is compact in morphology, and the kidney tubule is normal in morphology, and has no obvious difference from a normal control group. Compared with kidney tissues of the P6 and Fuc treatment groups, the P1-P5 heteropolysaccharide group can effectively improve and prevent the injury effect of high uric acid on kidneys, and the effect is superior to that of the P6 and Fuc.

Example 16

Effect of P1 and P3 on improvement of inflammation in gouty arthritis mouse model

60 rats were randomly selected and divided into a normal control group, a model group, a positive drug group (colchicine group), and brown algae heteropolysaccharides P1 and P3, each group having 10 rats. The P1 and P3 heteropolysaccharide were respectively administered by gastric lavage at a dose of 200mg/kg 5 days prior to molding; colchicine groups were administered daily at 280 mg/kg colchicine lavage 3 days prior to molding; respectively administering equal volumes of distilled water to a normal control group and a model group; 1 time a day. After the last administration of 1 h, after rats of the model group and each drug group are anesthetized according to the Coderre molding method, the rats are inserted by taking the rear side of the ankle joint of the right hind limb as a puncture point, the inclined surface of the needle opening forms an angle of 45 degrees with the tibia to the front and upper sides to puncture the ankle joint cavity, a sodium urate solution (the total volume of which is 0.15 mL) of 100 g/L is injected into the joint cavity (taking the bulge of the opposite side of the joint capsule as an injection standard) by a 6-gauge needle, an acute gouty arthritis model is replicated, and the rats of the normal control group are injected with sterile physiological saline by the same method. After 5h of molding, the rat is anesthetized, the abdominal aorta is taken for blood, and after standing in a water bath at 37 ℃ until layering, the rat is centrifuged for 15 min at 3000 r, and serum is taken for standby.

TNF-a detection: application of tumor necrosis factor-a detection kit (Nanjing built bioengineering institute)

IL-6 detection: interleukin-6 detection kit (Nanjing built bioengineering institute)

IL-1 b detection: interleukin IL-1 b detection kit (Nanjing established bioengineering institute)

Effect of fucoidan P1 on joint swelling in rats with acute gouty arthritis: after molding, the normal control group rats have no abnormal behavior, the right ankle joint has no red swelling and the skin temperature is high; the model group and rats in each drug group have the conditions of dysphoria, right foot elevation, local reddening and swelling and high skin temperature, wherein the model group is more obvious than the other drug groups. The joint swelling index of each group of rats was compared, and found that the joint swelling index of each drug group was lower than that of the model group after molding, wherein 3h and 5h were significantly reduced after molding, suggesting that colchicine and fucoidan P1 have anti-inflammatory effects.

After intervention of fucoidan P1 and P3, serum of mice with hyperuricemia and rats with acute gouty arthritis has different levels of IL-6, IL-1 beta and TNF-alpha reduced, and the local joint swelling of rats with acute gouty arthritis in drug group is obviously improved compared with model group, see figure 10, and compared with normal control group in figure 10, P<0.05; compared with the model group ^# P<0.05, n=10. It is suggested that fucoidan P1 and P3 have anti-hyperuricemia and acute gouty arthritisInflammatory action.

Example 17

Effects of P1 and P3 on the Activity level of hyperuricemia mice inflammation-related factors

Experimental study shows that after intervention of fucoidan P1 and P3, the serum levels of uric acid, xanthine oxidase, creatinine and blood urea nitrogen in hyperuricemia mice and acute gouty arthritis rats are obviously reduced, as shown in FIG. 11, and in FIG. 11, compared with the normal control group, P is shown in the following formula<0.05; compared with the model group ^# P<0.05, n=10. P1 and P3 are suggested to have the effects of reducing uric acid and improving renal function for hyperuricemia and acute gouty arthritis.

In conclusion, the brown algae heteropolysaccharide provided by the invention has the effects of reducing uric acid, improving renal function and resisting inflammation on hyperuricemia and acute gouty arthritis. Can be used for preparing medicines or functional foods and health care products for preventing and treating hyperuricemia, gout and gouty arthritis.

The above embodiments are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention without departing from the design spirit of the present invention.

Claims

1. The brown algae heteropolysaccharide is characterized by comprising the following components in percentage by mass: 30-90% of polyglucuronic acid, 1-70% of heterozygous mannuronate and 0.1-30% of low-sulfation heterozygous glucan; the total mass fraction of polyglucuronic acid, heterozygous mannuronate and low-sulfation heterozygous glucan is not less than 90%; the brown algae heteropolysaccharide does not contain fucose;

the extraction steps of the brown algae heteropolysaccharide comprise:

pulverizing brown algae, extracting with water or dilute hydrochloric acid, filtering to obtain residue, adding the residue into sodium acetate water solution, heating for extraction, adding alcohol into the extractive solution, standing, precipitating, redissolving, and dialyzing to obtain brown algae heteropolysaccharide.

2. The brown algae heteropolysaccharide of claim 1, wherein the mass fraction of sodium acetate in the sodium acetate aqueous solution is 3-5%.

3. The brown algae heteropolysaccharide according to claim 1, wherein the temperature of the heating extraction is 100-120 ℃, the time is 1-3 hours, and the number of extraction times is 1-3.

4. The brown algae heteropolysaccharide of claim 1, wherein the alcohol is ethanol and the addition amount is 3-4 times the volume of the extract.

5. The fucoidin according to claim 1, wherein the components of polyglucuronic acid include any one or more of glucuronic acid tetrasaccharide, pentasaccharide, hexasaccharide, heptasaccharide, octasaccharide, nonasaccharide, decasaccharide, undecanose, dodecasaccharide, tridecanose, tetradecanose, pentadecanose, hexadecanose, heptadecanose, octadecanose, nonadecanose and icosane; the structure of the polyglucuronic acid includes (GlcA) _x Wherein x is the degree of polymerization of GlcA and the value is any integer from 4 to 20.

6. The fucoidin according to claim 1, wherein the component of the hybrid mannuronic acid comprises any one or more of mannuronic acid tetrasaccharide, pentasaccharide, hexasaccharide, heptasaccharide, octasaccharide, nonasaccharide, decasaccharide, undecane saccharide, dodecasaccharide, tridecane, tetradecane saccharide, pentasaccharide, hexadecane saccharide, heptasaccharide, octadecane saccharide, nonasaccharide and eicosane; the structure of the hybrid mannuronate includes (GlcA) _x (Man) _y Wherein x is the degree of polymerization of GlcA, the value is any integer from 2 to 10, y is the degree of polymerization of Man, and the value is any integer from 2 to 10.

7. The brown algae heteropolysaccharide of claim 1, wherein the low sulfated heterozygous glucan component comprises sulfated heterozygous glucan tetraose, pentasaccharide, hexasaccharide, heptasaccharide, octasaccharide, nonasaccharideAny one or more of ten sugar, undecanose, dodecanose, tridecanose, tetradecanose, pentadecanose, hexadecanose, heptadecanose, octadecanose, nonadecanose and eicosanose; the structure of the low-sulfated hybrid glucan comprises (Glc) _x (Xyl) _z S _n Wherein x is the polymerization degree of GlcA, the value is any integer from 2 to 10, z is the polymerization degree of Xyl, the value is any integer from 2 to 10, n is the substitution number of sulfuric acid groups, the value is any integer from 1 to 10, and the substitution position of the sulfuric acid groups is at the C2 position, the C3 position or the C4 position of xylose.

8. The use of the fucoidin of any one of claims 1-7 in the preparation of a preparation for inhibiting xanthine oxidase activity.

9. The use of the fucoidin of any one of claims 1-7 in the preparation of uric acid activity lowering preparations.

10. The use of the fucoidin according to any one of claims 1-7 in the preparation of a medicament or food for reducing uric acid, preventing hyperuricemia, treating hyperuricemia, preventing gout or treating gout.