Gardenia polysaccharide as well as preparation method and application thereof

Abstract

The invention relates to the technical field of traditional Chinese medicine extracts and biological medicines, in particular to gardenia polysaccharide as well as a preparation method and application thereof. The gardenia polysaccharide disclosed by the invention consists of mannose, rhamnose, galacturonic acid, glucose, galactose and arabinose. The molar ratio of the mannose to the rhamnose to the galacturonic acid to the glucose to the galactose to the arabinose is 4.59 to 4.65 to 34.35 to 9.38 to 13.9 to 33.13; the content of total sugar is 83.1%, the content of uronic acid is 32.8%, and protein is not contained; and the molecular weight of the polypeptide is 4.3-652.9 kDa. In-vitro tests prove that the gardenia polysaccharide has relatively strong anticomplement activity and can be further used as an active component for preparing anticomplement drugs; whole animal tests prove that the gardenia polysaccharide can effectively relieve mouse acute lung injury induced by endotoxin and can be further used as an active component to prepare the medicine for preventing and treating acute lung injury.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of traditional Chinese medicine extracts and biological medicine technology, and particularly relates to gardenia polysaccharide and a preparation method and application thereof. BACKGROUND

[0002] Acute lung injury (ALI) is a clinical critical illness induced by various factors such as severe infection, trauma and shock, and its pathological feature is diffuse alveolar capillary membrane injury, which further leads to lung edema and increased permeability, and it is the early stage of acute respiratory distress syndrome (ARDS). The core pathophysiological changes of the disease include decreased lung compliance, increased intrapulmonary shunt and imbalance of ventilation / blood flow ratio, and the clinical manifestations are mainly refractory hypoxemia and respiratory distress, and the mortality rate is high. Domestic and foreign scholars have confirmed that ALI may be essentially an immunological disease with acute immune damage and immune clearance as the core mechanism, mainly manifested as mononuclear macrophage and other inflammatory cell infiltration, overexpression of various cytokines and adhesion molecules, and excessive activation of the complement system. It has been found that anaphylatoxins (such as C3a and C5a) produced after excessive activation of the complement can promote the aggregation of neutrophils in the lung, destroy the alveolar capillary wall, increase the vascular permeability, and further cause lung edema, reduce blood oxygen content, and further aggravate endothelial cell damage, forming a pathological vicious cycle of ALI. Therefore, finding a highly effective and low-toxicity complement inhibitor is one of the effective ways to develop drugs for preventing and treating ALI. At present, the therapeutic drugs for ALI in clinical practice are mainly glucocorticoids and antibiotics, but the overall efficacy is limited and there are obvious limitations: glucocorticoids have certain anti-inflammatory effect, but lack specificity, have significant side effects, and long-term or large-dose use can easily lead to immune function suppression and secondary infection; and the biological agents targeting the complement (such as sCR1 and C5 monoclonal antibody) have achieved certain effect in clinical application, but their high price limits their wide promotion. Therefore, developing ALI prevention and treatment drugs with high efficiency, low toxicity and economy has become an urgent need to be solved in clinical practice.

[0003] Gardenia is a plant of Rubiaceae Gardenia jasminoidesGardenia jasminoides Ellis, which is cold in nature and bitter in taste, belongs to the meridians of heart, lung and Sanjiao, and has the effects of purging fire and removing restlessness, clearing heat and dampness, and cooling blood and detoxifying. As a traditional Chinese medicine for clearing heat and purging fire, Gardenia jasminoides Ellis has a long history in the treatment of lung diseases in the theoretical system of traditional Chinese medicine. Many classic prescriptions for treating lung diseases (such as Qingjin Huatan Decoction, Zhizi Xingwu Decoction, Zhizi Chish Decoction, and Huanglian Jiedu Decoction) and commonly used Chinese patent medicines (such as Qingfei Yihuo Pill, Qinzhiliangfei Granules, and Lingyang Qingfei Capsules) contain Gardenia jasminoides Ellis as one of the core components. Modern pharmacological studies have shown that Gardenia jasminoides Ellis has anti-inflammatory, antibacterial, antipyretic, analgesic, antiviral, cholagogic, sedative, and antihypertensive activities, and its main chemical components include iridoid glycosides (such as gardenoside), volatile oil, polysaccharides, flavonoids, organic acids, and diterpenoids. Previous studies have shown that Gardenia jasminoides Ellis extract can effectively inhibit acute viral lung injury in mice caused by influenza A virus; gardenoside can significantly inhibit acute lung injury induced by lipopolysaccharide in mice and viral pneumonia induced by influenza virus; and Gardenia jasminoides Ellis polysaccharides can delay the progression of pulmonary fibrosis induced by TGF-β. However, no related reports have been found on the inhibition of complement activation by Gardenia jasminoides Ellis, and the prevention and treatment of acute lung injury by Gardenia jasminoides Ellis polysaccharides. SUMMARY

[0004] The present application aims to provide a Gardenia jasminoides Ellis polysaccharide, a preparation method thereof, and a new use thereof in the pharmaceutical industry, and particularly relates to the use of Gardenia jasminoides Ellis polysaccharide in the preparation of anti-complement drugs and drugs for preventing and treating acute lung injury.

[0005] To achieve the above-mentioned application purposes, the present application provides the following technical solutions. According to one of the technical solutions of the present application, a Gardenia jasminoides Ellis polysaccharide is provided, which is composed of mannose, rhamnose, galacturonic acid, glucose, galactose, and arabinose. The molar ratio of the mannose, rhamnose, galacturonic acid, glucose, galactose, and arabinose is 4.59:4.65:34.35:9.38:13.9:33.13. The content of total sugar in the Gardenia jasminoides Ellis polysaccharide is 83.1%, the content of sugar acid is 32.8%, and the Gardenia jasminoides Ellis polysaccharide does not contain protein; the molecular weight of the Gardenia jasminoides Ellis polysaccharide is 4.3-652.9 kDa.

[0006] According to the second technical solution of the present application, a preparation method of the Gardenia jasminoides Ellis polysaccharide is provided, which comprises the following steps. (1) Gardenia jasminoides Ellis dried fruits and ethanol are mixed, ultrasonic extraction is performed, and residue is obtained by filtration; (2) The residue is soaked in water, extraction is performed, and an extraction solution is obtained by filtration; (3) The extraction solution is concentrated, the obtained concentrated solution and ethanol are subjected to alcohol precipitation, the precipitate is collected, and the Gardenia jasminoides Ellis polysaccharide is obtained by purifying and drying the precipitate.

[0007] The third aspect of the present application provides application of the gardenia polysaccharide in the preparation of an anti-complement drug.

[0008] The fourth aspect of the present application provides application of the gardenia polysaccharide in the preparation of a drug for preventing and treating acute lung injury.

[0009] Compared with the prior art, the present application has the following beneficial effects: The present application separates and extracts a total polysaccharide extract from gardenia (Fructus Gardeniae) Gardenia jasminoides The product has a yield of 6.9%, a total sugar content of 83.1%, a uronic acid content of 32.8%, no protein, and a molecular weight of 4.3-652.9 kDa; in vitro tests prove that the gardenia polysaccharide has strong anti-complement activity and has a significant inhibitory effect on complement activation, and can be further used as an active ingredient for preparing an anti-complement drug; whole animal tests prove that the gardenia polysaccharide can effectively relieve endotoxin-induced acute lung injury in mice, and can be further used as an active ingredient for preparing a drug for preventing and treating acute lung injury. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 It is a high-performance gel permeation chromatogram of the gardenia polysaccharide of the present application.

[0011] Figure 2 It is an infrared spectrum of the gardenia polysaccharide of the present application.

[0012] Figure 3 It is a high-performance liquid chromatogram of the monosaccharide composition of the gardenia polysaccharide of the present application.

[0013] Figure 4 It is an effect of the gardenia polysaccharide of the present application on the lung index of an endotoxin (LPS)-induced acute lung injury mouse. p <0.01, p <0.001.

[0014] Figure 5 It is an effect of the gardenia polysaccharide of the present application on the lung tissue pathological changes of an endotoxin (LPS)-induced acute lung injury mouse.

[0015] Figure 6 It is an effect of the gardenia polysaccharide of the present application on inflammation in lung homogenate of an endotoxin (LPS)-induced acute lung injury mouse, wherein (A) is IL-1β (A), (B) is IL-6 (B), and (C) is TNF-α. p <0.05, p <0.01, p <0.001. DETAILED DESCRIPTION

[0016] The following detailed description of various exemplary embodiments of the application will not be considered limiting of the application, but rather a description of certain aspects, features and embodiments of the application.

[0017] 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 application. Additionally, for a range of values of a parameter, unless otherwise stated, each intervening value by each intervening value, as well as any other stated or intervening value in that stated range is encompassed. The upper and lower limits of these intervening values can independently be included or excluded in the range, and each smaller range that falls within the ambit of the recited ranges is also encompassed. These smaller ranges are not precluded from the scope of the application even though the smaller ranges are not explicitly recited or are not individually singled out.

[0018] Unless defined otherwise, 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 application belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All documents mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In case of conflict, the content of the present specification will control.

[0019] Various modifications and changes can be made to the specific embodiments of the application described herein without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those of ordinary skill in the art from the description and examples presented herein. The specification and examples given should be considered exemplary only, and should not be used to restrict the scope or spirit of the application.

[0020] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that mean including, but not limited to.

[0021] The room temperature described in the application is 25±2℃.

[0022] The raw materials used in the application can be obtained commercially or prepared by prior art.

[0023] The application provides a gardenia polysaccharide composed of mannose, rhamnose, galacturonic acid, glucose, galactose and arabinose. The molar ratio of the mannose, rhamnose, galacturonic acid, glucose, galactose and arabinose is 4.59:4.65:34.35:9.38:13.9:33.13. The content of total sugar in the gardenia polysaccharide is 83.1%, the content of uronic acid is 32.8%, and the gardenia polysaccharide is free of protein; the molecular weight of the gardenia polysaccharide is 4.3-652.9 kDa.

[0024] In the present application, the Gardenia is the dried mature fruit of Gardenia jasminoides Ellis. Gardenia jasminoides

[0025] The present application also provides a preparation method of the Gardenia polysaccharide, comprising the following steps: (1) mixing the dried fruit of Gardenia jasminoides Ellis and ethanol, performing ultrasonic extraction, and filtering to obtain residue; (2) soaking the residue in water, performing extraction, and filtering to obtain an extract; (3) concentrating the extract, collecting the precipitate obtained by alcohol precipitation of the concentrated extract and ethanol, and purifying and drying the precipitate to obtain the Gardenia polysaccharide.

[0026] In step (1) of the present application, the dried fruit of Gardenia jasminoides Ellis is added into ethanol, and ultrasonic extraction is performed to remove lipid components, and the residue is obtained after filtration, and the residue is dried at room temperature.

[0027] In the present application, the volume concentration of ethanol in step (1) is 95%; the solid-liquid ratio of the dried fruit of Gardenia jasminoides Ellis and ethanol is 1:15 (g:L); and the power of ultrasonic extraction is 80-120 kW, the time is 1 h, and the extraction is repeated once.

[0028] In step (2) of the present application, the dried residue is soaked in water, extraction is performed, and filtration is performed, and the extraction is repeated four times, and the filtrates of the four times are combined to obtain an extract.

[0029] In the present application, the solid-liquid ratio of the residue and water is 1:15 (g:L); the soaking temperature is room temperature, and the time is 12 h; the extraction temperature in step (2) is 100 ℃, the time is 2 h, and the extraction is repeated four times.

[0030] In step (3), the extract is concentrated under reduced pressure, the precipitate is removed by centrifugation of the concentrated extract, the supernatant is mixed with ethanol to perform alcohol precipitation, the precipitate is collected after standing and centrifugation, the precipitate is purified, concentrated and freeze-dried to obtain the Gardenia polysaccharide.

[0031] In the present application, the concentration temperature is 50-70 ℃, and the volume of the concentrated extract is 1 / 8 of the volume of the extract; the volume ratio of the concentrated extract and ethanol is 1:5; the volume concentration of ethanol in step (3) is 95%; and the time of alcohol precipitation is 18-28 h.

[0032] In the present application, the purification method is that the precipitate is dissolved in water and dialyzed; the molecular cut-off of the dialysis bag used for dialysis is 3500 Da, and the dialysis time is 2-3 days.

[0033] The present application also provides the use of the Gardenia polysaccharide in the preparation of an anti-complement drug.

[0034] ​The application also provides application of the gardenia polysaccharide in the above description in preparation of a medicine for preventing and treating acute lung injury, and in treatment of acute lung injury and acute respiratory distress syndrome.

[0035] The total polysaccharide extract is obtained by separation and extraction from gardenia. The total polysaccharide extract is proved to have strong anti-complement activity by in-vitro experiments, and is proved to have strong prevention and treatment effects on acute lung injury by whole animal model experiments.

[0036] In the application, the gardenia polysaccharide can also be used for preparation of medicines for preventing and treating severe atypical pneumonia, virus-bacteria co-infection pneumonia, human avian influenza, H1N1 influenza A and seasonal influenza, in view of similar pathological characteristics and pathophysiological changes of the acute lung injury.

[0037] The technical solutions provided by the application are described in detail below in combination with examples, but they should not be understood as limitations to the protection scope of the application.

[0038] Example 1 (1) 100 g of gardenia medicinal materials were added into 95% ethanol solution at a solid-liquid ratio of 1:15 (g:L) for ultrasonic extraction at 120 kW for 1 h, and the extraction was repeated once to remove lipid components, and then the medicinal residue was obtained by filtration; (2) The medicinal residue was dried at room temperature in a ventilated place, and then water was added at a solid-liquid ratio of 1:15 (g:L) for immersion at room temperature for 12 h, and then the immersion was extracted at 100 ℃ for 4 times, each for 2 h, and then the filtrate was obtained by filtration, and the volume of the concentrated solution was 1 / 8 of the filtrate, and the concentrated solution was centrifuged to remove the precipitate; (3) The supernatant was alcohol precipitated with 95% ethanol, and the volume ratio of the extract to ethanol was 1:5 (v / v), and then the precipitate was collected by centrifugation after standing for 24 h. (4) The precipitate was redissolved with water and dialyzed (the molecular weight cut-off of the dialysis bag was 3500 Da) for 2-3 days, and then the gardenia total polysaccharide GJP was obtained by concentration and freeze-drying (6.9 g, the yield was 6.9%).

[0039] Test Example 1 Structure characterization of gardenia polysaccharide (1) Analysis of molecular weight Sample treatment: 2.0 mg of gardenia polysaccharide sample was taken in a centrifuge tube, 0.5 mL of 0.02 mol / L ammonium acetate solution was added for dissolution, and then the solution was filtered with a 0.22 μL membrane for HPLC analysis.

[0040] Chromatographic conditions: Column: TSKgel G4000SWXL (300 × 7.8 mm, 8 μm); Mobile phase: 0.02 mol / L ammonium acetate; Flow rate: 0.6 mL / min; Injection volume: 20 μL; Column temperature: 40 ℃; Detector: Refractive index detector (RID).

[0041] The characteristic chromatogram of Gardenia polysaccharide GJP on high performance liquid chromatography gel permeation chromatography is as follows: Figure 1 As shown, its molecular weight ranges from 4.3 to 652.9 kDa.

[0042] (2) Determination of total sugar, uronic acid and protein content The total sugar content of Gardenia polysaccharide GJP was determined to be 83.1% using the sulfuric acid-phenol method; the uronic acid content of Gardenia polysaccharide GJP was determined to be 32.8% using the m-hydroxybiphenyl method; and the protein content of Gardenia polysaccharide GJP was determined to be 0% using the Coomassie brilliant blue method.

[0043] (3) Infrared spectral analysis 2.0 mg of dried gardenia polysaccharide was ground with KBr, compressed into tablets, and analyzed using a PerkinElmer Fourier transform infrared spectroscopy (FTIR) instrument at 4000–4000 cm⁻¹. -1 Scan within the range.

[0044] like Figure 2 As shown in the infrared spectrum, the gardenia polysaccharide of the present invention contains characteristic absorption peaks of polysaccharides.

[0045] (4) Monosaccharide composition analysis Gardenia polysaccharide was completely hydrolyzed with 2 mol / L trifluoroacetic acid (TFA) at 110 °C to obtain monosaccharide residue products. After derivatization with 1-phenyl-3-methyl-5-pyrazolone (PMP) and extraction with trichloroacetic acid, the product was filtered through a 0.22 μL filter membrane and then analyzed by HPLC.

[0046] like Figure 3 As shown, Gardenia polysaccharide GJP is composed of six monosaccharides with a monosaccharide molar ratio of mannose:rhamnose:galacturonic acid:glucose:galactose:arabinose = 4.59:4.65:34.35:9.38:13.90:33.13.

[0047] Test Example 2: Classical Pathway Complement Inhibition Test The complement sources for this classic pathway were: serum from 3-month-old guinea pigs, diluted 1:100 with BBS buffer (barbital buffer, pH=7.4); hemolysin: rabbit anti-sheep erythrocyte antibody diluted 1:1000 with BBS buffer; and sheep erythrocytes (SRBC) prepared as 2% SRBC.

[0048] Precisely weigh about 3 mg of Gardenia jasminoides Ellis polysaccharide GJP, dissolve in BBS buffer, and dilute by 2 to obtain 8 concentrations. Take 200 μL of polysaccharide solution of different concentrations and 200 μL of complement diluted to 1:100, and pre-incubate at 37 ℃ for 10 min, then add 1:1000 hemolysin (100 μL) and 2% SRBC (100 μL), continue to incubate at 37 ℃ for 30 min, and then put into a low-temperature high-speed centrifuge, centrifuge at 5000 rpm and 4 ℃ for 10 min. Take 200 μL of supernatant of each sample in a 96-well plate, and measure the absorbance at 405 nm wavelength. The experiment also sets up a polysaccharide control group (take 200 μL of polysaccharide solution of the corresponding concentration and add 400 μL of BBS buffer), a complement control group (replace the polysaccharide with 200 μL of BBS buffer), and a complete hemolysis group (take 100 μL of 2% SRBC and dissolve in 500 μL of distilled water). Subtract the absorbance value (corresponding polysaccharide control group) from the absorbance value (polysaccharide group of each concentration) to calculate the hemolysis inhibition rate. Take the logarithmic value of the polysaccharide concentration as the X-axis and the hemolysis inhibition rate as the Y-axis to plot a fitting curve, and calculate the concentration of polysaccharide sample required for 50% hemolysis inhibition (CH 50 The results show that Gardenia jasminoides Ellis polysaccharide GJP has significant inhibitory activity on the activation of the complement classical pathway (as shown in Table 1).

[0049] Table 1 Inhibitory effect of Gardenia jasminoides Ellis polysaccharide and heparin on complement activation

[0050] CH 50 The CH 50 value is expressed as: mean ± SD (n=3) Test Example 3 Effect of Gardenia jasminoides Ellis polysaccharide GJP on LPS-induced acute lung injury mice Male BALB / c mice 30 (18-22 g) were randomly set 5 groups according to body weight (normal group, gardenia polysaccharide low-dose group, gardenia polysaccharide high-dose group, positive drug dexamethasone group). Different groups of drugs as follows: normal group (Normal) and model group (LPS) were given normal saline; gardenia polysaccharide low-dose group (GJP-L) and gardenia polysaccharide high-dose group (GJP-H) were given 50 mg / kg and 100 mg / kg GJP respectively, and the positive drug group (DEX) was given 5 mg / kg dexamethasone. Mice were given gavage, once a day, for 3 consecutive days. 1 hour after the 3rd day of administration, except for the normal group of mice, the rest of the mice were given 3 mg / kg LPS by nasal drops to induce acute lung injury. After 24 hours of LPS treatment, all mice were weighed, and the eyeball was taken to draw blood; the whole lung tissue was carefully cut off and weighed; it was placed in 10% formalin solution to make pathological sections for pathological evaluation; the right lung was stored in a-80℃ refrigerator for detection of lung-related factor indicators.

[0051] (1) The effect of gardenia polysaccharide GJP on lung index of LPS-induced acute lung injury mice The lung index is the ratio of lung weight to body weight of mice, and the larger the ratio, the more serious the lung lesion. The results are shown in Figure 4 Compared with the normal group, the lung index of the model group mice was significantly increased p <0.001); the lung index of the low-dose (GJP-L) and high-dose (GJP-H) gardenia polysaccharide administration groups and the positive drug group (DEX) was significantly lower than that of the model group p <0.01, p <0.001, p <0.001). Gardenia polysaccharide GJP can significantly reduce the lung edema of LPS-induced mice.

[0052] (2) The effect of gardenia polysaccharide GJP on lung pathological changes of LPS-induced acute lung injury mice As shown in Figure 5 , the pathological examination results showed that compared with the normal group, the model group mice had obvious thickening of alveolar wall, atrophy and deformation of alveoli, bleeding in the lung, and a large number of inflammatory cell infiltration in the lung interstitium, and the inflammation was more serious. The low-dose and high-dose gardenia polysaccharide administration groups (GJP-L and GJP-H) and the positive drug group (DEX) significantly improved the lung pathological tissue damage, the alveolar profile was clear, and there was a complete alveolar structure, the inflammatory cell content of alveolar wall was less, and the inflammatory cell infiltration was obviously reduced.

[0053] (3) The effect of gardenia polysaccharide GJP on lung inflammation of LPS-induced acute lung injury mice The supernatant of lung homogenate was detected according to the kit instructions of IL-1β, IL-6 and TNF-α by ELISA method. The results are shown in Table 1 Figure 6 As shown in Table 1, compared with the normal group, the levels of IL-1β, IL-6 and TNF-α in the lung homogenate of the model group were significantly increased (P < 0.001, p <0.001、 p <0.001、 p <0.001). The levels of IL-1β in the lung homogenate of the low dose (GJP-L) and high dose (GJP-H) groups of gardenia polysaccharide and the positive drug group (DEX) were significantly lower than those of the model group (P < 0.01, p <0.01、 p <0.001、 p <0.001). The levels of IL-6 in the lung homogenate of the low dose (GJP-L) and high dose (GJP-H) groups of gardenia polysaccharide and the positive drug group (DEX) were significantly lower than those of the model group (P < 0.05, p <0.05、 p <0.05、 p <0.01). Similarly, the levels of TNF-α in the lung homogenate of the low dose (GJP-L) and high dose (GJP-H) groups of gardenia polysaccharide and the positive drug group (DEX) were significantly lower than those of the model group (P < 0.01, p <0.01、 p <0.001、 p <0.001). Gardenia polysaccharide GJP can significantly reduce the recruitment of inflammatory cells and relieve the inflammatory infiltration and inflammation degree of the lung of LPS infected mice.

[0054] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, several improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A gardenia polysaccharide, characterized in that, consisting of mannose, rhamnose, galacturonic acid, glucose, galactose and arabinose; The molar ratio of the mannose, rhamnose, galacturonic acid, glucose, galactose and arabinose is 4.59:4.65:34.35:9.38:13.9:33.13; The content of total sugar in the gardenia polysaccharide is 83.1%, the content of uronic acid is 32.8%, and the gardenia polysaccharide is free of protein; the molecular weight of the gardenia polysaccharide is 4.3-652.9 kDa.

2. The preparation method of the gardenia polysaccharide according to claim 1, characterized in that, The method comprises the following steps: (1) mixing dried fruits of gardenia and ethanol, performing ultrasonic extraction, and filtering to obtain residue; (2) soaking the residue in water, performing extraction, and filtering to obtain an extract; (3) concentrating the extract, mixing the concentrated solution with ethanol to perform alcohol precipitation, collecting the precipitate, and purifying and drying the precipitate to obtain the gardenia polysaccharide.

3. The preparation method according to claim 2, characterized in that, In step (1), the volume concentration of ethanol is 95%; the solid-liquid ratio of the dried fruits of gardenia and ethanol is 1:15 (g:L); the ultrasonic extraction is performed at a power of 80-120 kW for 1 h, and the extraction is repeated once.

4. The preparation method according to claim 2, characterized in that, The solid-liquid ratio of the residue and water is 1:15 (g:L); the soaking is performed at room temperature for 12 h; in step (2), the extraction is performed at a temperature of 100 ℃ for 2 h, and the extraction is repeated 4 times.

5. The preparation method according to claim 2, characterized in that, The concentration is performed at a temperature of 50-70 ℃, and the volume of the concentrated solution is 1 / 8 of the volume of the extract; the volume ratio of the concentrated solution and ethanol is 1:5; in step (3), the volume concentration of ethanol is 95%; the alcohol precipitation is performed for 18-28 h.

6. The method of claim 2, wherein, The purification method is: dissolving the precipitate in water, and performing dialysis; the molecular cut-off of the dialysis bag used for dialysis is 3500 Da, and the dialysis is performed for 2-3 days.

7. Use of the gardenia polysaccharide of claim 1 in the preparation of an anti-complement drug.

8. Use of the gardenia polysaccharide of claim 1 in the preparation of a drug for preventing and treating acute lung injury.

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