Gardenia polysaccharide as well as preparation method and application thereof

Abstract

The invention provides gardenia polysaccharide, a preparation method thereof and application of the gardenia polysaccharide in preparation of medicines for treating pulmonary fibrosis, and relates to the technical field of traditional Chinese medicine extracts and biological medicines. The gardenia polysaccharide GP121 with a new polysaccharide structure is extracted from gardenia, and the gardenia polysaccharide GP121 provided by the invention is simple in extraction method, high in polysaccharide extraction rate and low in production cost. The invention further researches the anti-pulmonary fibrosis biological activity of the gardenia polysaccharide GP121 on the basis of the cellular level, and the research result shows that the gardenia polysaccharide GP121 provided by the invention has the effect of delaying the MRC-5 cell fibrosis process caused by TGF-beta1; the phosphorylation of the Smad3 protein is inhibited, so that the expression of alpha-SMA, CollagenI and FN protein is reduced, and the fibrosis process is delayed. The gardenia polysaccharide GP121 provided by the invention can be used as a potential therapeutic drug for treating pulmonary fibrosis, and a new application of the gardenia polysaccharide in the aspect of treating pulmonary fibrosis is provided.

Description

Technical Field

[0001] The invention relates to the technical field of traditional Chinese medicine extracts and biomedicine, and in particular to a gardenia polysaccharide and a preparation method thereof and application thereof in preparing a medicine for treating pulmonary fibrosis. Background Art

[0002] Pulmonary fibrosis (PF) is a fibrotic disease caused by irritation or impact on lung tissue, resulting in massive inflammatory infiltration in the lungs, excessive deposition of extracellular matrix, and abnormal proliferation of connective tissue. The incidence of the disease is increasing and it is difficult to cure, which can easily lead to organ structure destruction and functional impairment, and even endanger life. Currently, the commonly used drugs for the treatment of pulmonary fibrosis in clinical practice include anti-fibrotic drugs such as nintedanib, pirfenidone, and glucocorticoid immunosuppressants, but these drugs can only delay the decline of lung function and have high toxic side effects. Therefore, it is of great significance to find new drugs for the treatment of pulmonary fibrosis.

[0003] Gardenia jasminoides Ellis is the dried mature fruit of the Rubiaceae plant Gardenia. The fruit is long oval or elliptical; the surface is reddish yellow or brownish red; the peel is thin and crisp, slightly shiny; the inner surface is lighter in color and shiny; the smell is slight, and the taste is slightly sour and bitter. The dried mature fruit is used as medicine, which is cold in nature, bitter in taste, and enters the heart, lung, and triple burner meridians. It has the effects of purging fire and relieving restlessness, clearing heat and removing dampness, cooling blood and detoxifying. Gardenia contains polysaccharides, iridoids, volatile oils, flavonoids, diterpenes and other ingredients, which have neuroprotective, anti-inflammatory, sugar-controlling, liver-protecting, and choleretic effects. Gardenia polysaccharides, as one of the important pharmacological material bases in Gardenia, have biological activities such as anti-inflammatory, antioxidant, immunomodulatory, and bile acid stasis regulation.

[0004] At present, the specific pathogenesis of pulmonary fibrosis is still unclear, and it is urgent to find a therapeutic drug with definite efficacy and low toxicity and side effects. The present invention aims to provide a pure polysaccharide extract of Gardenia jasminoides with a new structure extracted and separated from Gardenia jasminoides, and to study the application of the polysaccharide in the treatment of pulmonary fibrosis. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the deficiencies in the prior art, the present invention provides a gardenia polysaccharide and a preparation method thereof, as well as application of the gardenia polysaccharide in the preparation of a drug for treating pulmonary fibrosis.

[0007] (II) Technical solution

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0009] In a first aspect, the present invention provides a gardenia polysaccharide, the structural formula of the gardenia polysaccharide is as follows:

[0010]

[0011] In the above structure, Galp represents galactose, Glcp represents glucose, Rhap represents rhamnose, GalpA represents galacturonic acid, GlcpA represents galacturonic acid, and Ara represents arabinose.

[0012] Furthermore, the molecular weight range of the Gardenia polysaccharide is 1-90 kDa.

[0013] Furthermore, the molecular weight of the gardenia polysaccharide ranges from 30 to 77.5 kDa.

[0014] The second invention provides a method for preparing Gardenia polysaccharide, wherein the Gardenia polysaccharide is prepared according to the following steps:

[0015] 1) crushing the dried gardenia into powder using a pulverizer, and defatting the powder in industrial ethanol to obtain defatted gardenia;

[0016] 2) extracting the defatted gardenia in step 1) by boiling water extraction method for 4-6 times, then combining the extracts, concentrating to one fifth of the volume of the extracts, centrifuging to remove the precipitate, and retaining the supernatant; dialyzing the supernatant with running water for more than 72 hours, and then standing overnight; obtaining a polysaccharide precipitate after centrifugation, and drying at 60° C. to obtain a crude gardenia polysaccharide GP;

[0017] 3) The crude Gardenia polysaccharide obtained in step 2) was dissolved in deionized water, stirred overnight, centrifuged, and the supernatant was loaded onto a DEAE SepharoseTM Fast Flow anion exchange column, and gradient eluted with deionized water, 0.1M, and 0.2M NaCl solutions in sequence, with the flow rate controlled at 100mL / min, and collected with an automatic collector; 20μL was taken from each tube, and the color was developed with sulfuric acid-phenol method and its absorbance was detected at 490nm with an enzyme marker, and the elution curve was drawn with absorbance and elution volume; the corresponding polysaccharide components were collected according to the elution curve, and then concentrated, dialyzed, and freeze-dried; another crude Gardenia polysaccharide was taken, and the polysaccharide was further separated and purified using the above method; finally, the polysaccharide components eluted twice with 0.1M NaCl were combined and named GP1; GP1 was dissolved in deionized water, centrifuged at 3500r / min for more than 10min, and the supernatant was loaded onto a Sephacryl S-200HR gel column, and 0.2M The product was eluted with NaCl solution at a flow rate of 0.3 mL / min, and the corresponding components were collected by an automatic collector. The elution curve was drawn using the sulfuric acid-phenol method, and the desired components were collected and concentrated, dialyzed, and freeze-dried to finally obtain Gardenia polysaccharide, which was named GP121.

[0018] Furthermore, in step 1) of the above preparation method, the dialysis fluid used for running water dialysis is a mixture of the extract and 95% ethanol by volume in a volume ratio of 1:3-5.

[0019] In a third aspect, the present invention provides the use of Gardenia polysaccharide GP121 in the preparation of a drug for treating pulmonary fibrosis.

[0020] (III) Beneficial effects

[0021] The present invention extracts Gardenia polysaccharide GP121 with a new polysaccharide structure from Gardenia. The Gardenia polysaccharide GP121 provided by the present invention has a simple extraction method, a high polysaccharide extraction rate and a low production cost. The present invention further studies the anti-pulmonary fibrosis biological activity of Gardenia polysaccharide GP121 on a cellular level. The research results show that the Gardenia polysaccharide GP121 provided by the present invention has the effect of delaying the fibrosis process of MRC-5 cells caused by TGF-β1, and delays the process of fibrosis by inhibiting the phosphorylation of Smad3 protein and thereby reducing the expression of α-SMA, CollagenⅠ and FN protein. The Gardenia polysaccharide GP121 provided by the present invention can be used as a potential therapeutic drug for treating pulmonary fibrosis, and provides a new use of Gardenia polysaccharide in treating pulmonary fibrosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the HPGPC spectrum of Gardenia polysaccharide GP121.

[0023] Figure 2 This is the one-dimensional NMR spectrum of Gardenia polysaccharide GP121.

[0024] Figure 3 is the NMR spectrum of Gardenia polysaccharide GP121, where A is the 1 H NMR spectrum; B is the Gardenia polysaccharide GP121 13 C NMR spectrum.

[0025] Figure 4 The results show that the Gardenia polysaccharide GP121 inhibits the proliferation of MRC-5 cells induced by TGF-β1. Compared with the blank group, the model group ## P<0.01; compared with the model group, *P<0.05; **P<0.01.

[0026] Figure 5 This is the effect of Gardenia polysaccharide GP121 on the transcription of α-SMA, CollagenⅠ, and Fibronectin (FN) mRNA in MRC-5 cells induced by TGF-β1. Compared with the blank group, the model group ## P<0.01; compared with the model group, *P<0.05; **P<0.01.

[0027] Figure 6 This is the effect of Gardenia polysaccharide GP121 on the expression of α-SMA, CollagenⅠ and Fibronectin (FN) proteins in MRC-5 cells induced by TGF-β1. Compared with the blank group, the model group ## P<0.01; compared with the model group, *P<0.05; **P<0.01.

[0028] Figure 7 This is the effect of Gardenia polysaccharide GP121 on the phosphorylation of Smad3 protein induced by TGF-β1 in MRC-5 cells to delay the fibrosis process. Compared with the blank group, the model group ## P<0.01; compared with the model group, *P<0.05; **P<0.01. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Example 1

[0031] Preparation and determination of Gardenia jasminoides polysaccharide GP121

[0032] 1 Preparation of Gardenia polysaccharide GP121

[0033] 1) crushing the dried gardenia into powder using a pulverizer, and defatting the powder in industrial ethanol to obtain defatted gardenia;

[0034] 2) extracting 3.0 kg of defatted gardenia jasminoides in step 1) by boiling water extraction method for 4 times, then combining the extracts and concentrating them to one fifth of the volume of the extracts, and then centrifuging to remove the precipitate; dialyzing the supernatant with running water for more than 72 hours, and then standing overnight; obtaining a polysaccharide precipitate after centrifugation, and drying at 60° C. to obtain a crude gardenia polysaccharide GP; the dialyzate used for running water dialysis is a mixture of the extract and 95% ethanol by volume in a volume ratio of 1:3-5;

[0035] 3) 50 g of the crude Gardenia polysaccharide GP obtained in step 2) was dissolved in 500 mL of deionized water, stirred overnight, centrifuged, and the supernatant was loaded onto a DEAE SepharoseTM Fast Flow anion exchange column, and gradient eluted with deionized water, 0.1 M, and 0.2 M NaCl solutions in sequence, with the flow rate controlled at 100 mL / min, and collected with an automatic collector; 20 μL was taken from each tube, developed with sulfuric acid-phenol method, and its absorbance was detected at 490 nm with an ELISA reader, and an elution curve was drawn with absorbance and elution volume; the corresponding polysaccharide components were collected according to the elution curve, and then concentrated, dialyzed, and freeze-dried; another 50 g of the crude Gardenia polysaccharide GP was taken, and the polysaccharide was further separated and purified using the above method; finally, the polysaccharide components eluted twice with 0.1 M NaCl were combined and named GP1; 200 mg of the crude polysaccharide GP1 was dissolved in 5 mL of deionized water, centrifuged at 3500 r / min for 10 min, and the supernatant was loaded onto a Sephacryl The S-200HR gel column was eluted with 0.2M NaCl eluent, the flow rate was controlled at 0.3mL / min, and the corresponding components were collected by an automatic collector. The elution curve was drawn using the sulfuric acid-phenol method, and the desired components were collected and concentrated, dialyzed and freeze-dried to finally obtain pure Gardenia polysaccharide, named GP121.

[0036] 2 Determination of Gardenia polysaccharide GP121

[0037] 2.1 Experimental Purpose

[0038] The molecular weight, monosaccharide composition, sugar residue linkage mode and structure of Gardenia jasminoides pure polysaccharide GP121 were determined by HPGPC, HPLC, GC-MS and NMR.

[0039] 2.2 Experimental Materials

[0040] 2.2.1 Instruments

[0041] GL-2M centrifuge (Shanghai Luxiangyi Centrifuge Instrument Co., Ltd.); TGL-16C centrifuge (Shanghai Antingke Instrument Factory); 1ES-224DS electronic analytical balance (Tianjin Deant Sensing Technology Co., Ltd.); vortex oscillator (LICHEN Co., Ltd.); Agilent 1260 high performance liquid chromatography system (Agilent Corporation).

[0042] 2.2.2 Reagents

[0043] PMP (1-phenyl-3-methyl-5-pyrazolone), trifluoroacetic acid, and CMC (1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide methane-p-toluenesulfonate) were purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan). Other chemicals and reagents were of analytical grade and purchased from Sinopharm Chemical Reagent Co., Ltd.

[0044] 2.3 Methods

[0045] 2.3.1 Determination of molecular weight of Gardenia polysaccharide GP121

[0046] Polysaccharide GP121 was connected to KS-802 (exclusion limit 1x10 4 Da) and KS-804 (exclusion limit 4x10 5 Da) The chromatographic conditions of the characteristic spectrum on the gel column are: mobile phase: 0.1M NaNO3; flow rate: 0.6mL / min; Agilent 1260 liquid chromatograph; column temperature: 35°C; detectors: differential detector and ultraviolet detector.

[0047] 2.3.2 Determination of monosaccharide composition in Gardenia polysaccharide GP121

[0048] The monosaccharide composition was determined by HPLC using an Agilent 1260 liquid chromatograph with a flow rate of 1 mL / min, a column temperature of 25°C, an ultraviolet detection wavelength of 254 nm, and a sample injection volume of 10 μL / sample.

[0049] 2.3.3 Experimental study on the methylation GP121 linkage mode of Gardenia jasminoides polysaccharide

[0050] According to the monosaccharide composition analysis, the polysaccharide contains a small amount of acidic monosaccharides, so the Needs method was used for methylation experiments. First, 10 mg of dried sample was dissolved in 2 mL of dimethyl sulfoxide. Then, 100 mg of sodium hydroxide powder was quickly added and stirred at room temperature for 2.5 hours. After that, 1 mL of iodomethane was slowly added dropwise in an ice bath for methylation. The reaction mixture continued to stir at room temperature for 2.5 hours and then quenched with 2 mL of distilled water. After extraction, the methylated polysaccharide was hydrolyzed with 2 M trifluoroacetic acid at 110 ° C for 4 hours. Finally, acetylation was carried out at 100 ° C for 1.5 hours to obtain partially methylated acetylated alditols (PMAAs), which were analyzed by gas chromatography-mass spectrometry.

[0051] 2.3.4 NMR determination of Gardenia polysaccharide GP121

[0052] Take 30 mg of Gardenia polysaccharide GP121, add 0.5 mL D2O to dissolve, add 5 μL acetone as internal standard (δ=2.29 ppm, δ=31.5 ppm), and measure the one-dimensional NMR spectrum on a Bruker AVANCE III 500M NMR instrument.

[0053] 3 Results

[0054] like Figure 1 The HPGPC spectrum of GP121 shown is a single symmetrical peak, and its molecular weight is calculated to be 77.5 Kda

[0055] like Figure 2 The results showed that based on the total amount of sugars, Gardenia polysaccharide GP121 mainly contained galactose (35-42.88%), arabinose (35-44.45%), rhamnose (3-6.24%), galacturonic acid (2-4.61%), and glucose (1-1.81%).

[0056] The results of methylation are shown in Table 1. The connection modes of GP121 sugar residues include T-Ara, 1,3-Ara, 1,5-Ara, T-Rha, 1,2-Rha, T-Gal, 1,3,5-Ara, 1,2,4-Rha, 1,4-Gal, 1,4-GlcpA, 1,3-Gal, 1,6-Glc, 1,6-Gal, and 1,3,6-Gal.

[0057] Table 1 Methylation results of GP121

[0058] Linkages Molar Rato % T-Ara 11.24 1,3-Ara 9.79 1,5-Ara 18.41 T-Rha 0.99 1,2-Rha 2 T-Gal 10.43 1,3,5-Ara 3.26 1,2,4-Rha 3.38 1,4-Gal 19.09 1,4-GlcpA - 1,3-Gal 5.46 1,6-Glc 2.01 1,6-Gal 4.69 1,3,6-Gal 9.25

[0059] Figure 3 A represents polysaccharide GP121 1 H NMR spectrum, the chemical shifts of H1-H6 in the 1,6-linked galactan backbone were 4.55 ppm, 3.62 ppm, 3.71 ppm, 3.95 ppm, 3.84 ppm and 3.85 ppm, respectively. Figure 3 B represents polysaccharide GP121 13 The CNMR spectrum shows that the chemical shifts of C1-C6 are 104.41 ppm, 72.05 ppm, 73.57 ppm, 69.89 ppm, 74.01 ppm and 70.19 ppm.

[0060] The structure of the Gardenia polysaccharide GP121 prepared in this example is as follows:

[0061]

[0062] Example 2

[0063] This example provides the effect of Gardenia polysaccharide GP121 on TGF-β1-induced fibrosis in MRC-5 human embryonic lung fibroblasts, and is used to evaluate the application prospect of Gardenia polysaccharide GP121 in the preparation of drugs for the treatment of pulmonary fibrosis.

[0064] 1 Experimental Materials

[0065] BCA protein kit was purchased from Shanghai Solebow Biotechnology Co., Ltd. (Shanghai, China); ultrasensitive enhanced chemiluminescence assay (ECL) was purchased from Shanghai Yisheng Biotechnology Co., Ltd. (Shanghai, China); all primary and secondary antibodies were purchased from Beijing Bioson Biotechnology Co., Ltd. (Beijing, China); all experimental reagents were of analytical or chromatographic grade.

[0066] 2 Experimental Grouping and Treatment

[0067] MRC-5 cells were seeded in 96-well plates or 6-well plates, and blank group, model group, and groups treated with different doses of Gardenia polysaccharide GP121 (0μg / mL, 100μg / mL, 200μg / mL, 400μg / mL, 600μg / mL, 800μg / mL, 1000μg / mL) were set up. After overnight incubation for cell attachment, the culture medium containing 1% fetal bovine serum was replaced for starvation treatment for 6 hours, and new complete culture medium was replaced. TGF-β1 (concentration of 10ng / mL) was added to all groups except the blank group. The Gardenia polysaccharide GP121 treatment group was treated with different concentrations of polysaccharide solutions to explore the effect of Gardenia polysaccharide GP121 in treating TGF-β1-induced fibrosis in MRC-5 human embryonic lung fibroblasts.

[0068] 3 Effect of Gardenia polysaccharide GP121 on the proliferation rate of MRC-5 human embryonic lung fibroblasts induced by TGF-β1

[0069] MRC-5 cells were inoculated in 96 blanks and the experiment was carried out according to 2 experimental groups and treatments. MTT (0.5 mg / mL) was added to each well and incubated for 4 h. The culture medium was then discarded, and the cells were washed three times with PBS. 150 μL of DMSO was added to each well and shaken for 15 min. The absorbance was then measured at 570 nm.

[0070] 4. Detection of fibrosis marker mRNA by fluorescence quantitative PCR

[0071] The cell experiment was carried out according to the previous method. After the experiment, TRIZO was used to extract RNA. The extracted RNA was reverse transcribed into cDNA using a reverse transcription kit and then tested on a qRT-PCR machine. The program was set to pre-treat at 95°C for 20 seconds, followed by 40 cycles of 95°C for 15 seconds and 58°C for 20 seconds. The primer reference sequences are shown in Table 2:

[0072] Table 2 Primer sequences

[0073]

[0074] 5. Detection of related protein expression in lung tissue

[0075] Cell proteins were lysed with RIP protein lysis buffer, protein concentration was determined with BCA protein kit, and Loading buffer was adjusted to the same concentration. 20 μg protein was loaded into each lane, separated by SDS-PAGE electrophoresis, transferred to PVDF membrane, blocked with 5% skim milk powder, incubated with primary antibody, and incubated at 4°C overnight. After washing the membrane, the secondary antibody was incubated for 1 hour, and the expression of related proteins was detected by enhanced chemiluminescence (ECL) exposure. All data were quantified and normalized using Image software.

[0076] 6 Statistical analysis

[0077] All statistical analyses were performed using GraphPad Prism 8 software (GraphPad software, San Diego, CA, USA). All data results were presented as mean ± standard deviation (SD), and Student's t-test was used for comparison. One-way ANOVA was used to measure the p value of the differences between groups for multiple group comparisons.

[0078] 7 Results

[0079] like Figure 4 As shown, compared with the blank group, TGF-β1 can significantly cause the proliferation of MRC-5 human embryonic lung fibroblasts, and the difference is extremely significant (p<0.01); under the treatment of different concentrations of Gardenia polysaccharide GP121, the proliferation of MRC-5 human embryonic lung fibroblasts caused by TGF-β1 is significantly inhibited, and it is dose-dependent. The above results show that the Gardenia polysaccharide GP121 provided by the present invention has a significant inhibitory effect on the abnormal proliferation of MRC-5 cells caused by TGF-β1.

[0080] α-SMA, FN, and Collagen I are three factors related to cell fibrosis in MRC-5 cells. We used qRT-PCR to verify the effects of the Gardenia polysaccharide GP121 provided by the present invention on the above three factors. Figure 5-6 As shown, compared with the blank group, TGF-β1 can significantly increase the mRMA and protein expression of α-SMA, FN, and CollagenⅠ (p<0.01); compared with the model group, the mRMA and protein expression of α-SMA, FN, and CollagenⅠ in the Gardenia polysaccharide GP121 treatment group were significantly reduced (p<0.01). The above results show that the Gardenia polysaccharide GP121 provided by the present invention can significantly reduce the expression of α-SMA, FN, CollagenⅠ and fibrosis-related proteins, thereby inhibiting cell fibrosis.

[0081] In order to further explore the mechanism of Gardenia polysaccharide GP121 in reducing the expression of fibrotic proteins, we detected the phosphorylation expression of Smad3 protein in MRC-5 cells after treatment with Gardenia polysaccharide GP121. Figure 7 As shown in AB, compared with the blank group, the expression of Smad3 protein phosphorylation and the expression of fibrosis marker α-SMA in MRC-5 cells of the model group increased significantly (p<0.01); compared with the model group, the expression of Smad3 protein phosphorylation and the expression of fibrosis marker α-SMA in MRC-5 cells of the Gardenia polysaccharide GP121-treated group decreased significantly (p<0.01). The above results show that the Gardenia polysaccharide GP121 provided by the present invention can inhibit the phosphorylation of Smad3 protein and thus reduce the expression of fibrosis marker α-SMA, and Gardenia polysaccharide GP121 may exert its anti-pulmonary fibrosis effect by inhibiting the phosphorylation of Smad3 protein.

[0082] 8 Conclusion

[0083] The Gardenia polysaccharide GP121 provided by the present invention has the effect of delaying the fibrosis process of MRC-5 cells caused by TGF-β1, and delays the process of fibrosis by inhibiting the phosphorylation of Smad3 protein and then reducing the expression of α-SMA, Collagen I and FN protein. The Gardenia polysaccharide GP121 provided by the present invention can be used as a potential therapeutic drug for treating pulmonary fibrosis, providing a new use of Gardenia polysaccharide in treating pulmonary fibrosis.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A Gardenia polysaccharide, characterized in that: The structural formula of the Gardenia polysaccharide is as follows: In the above structure, Galp represents galactose, Glcp represents glucose, Rhap represents rhamnose, GalpA represents galacturonic acid, GlcpA represents galacturonic acid, and Ara represents arabinose.

2. The Gardenia polysaccharide according to claim 1, characterized in that: The molecular weight of the gardenia polysaccharide ranges from 1 to 90 kDa.

3. The Gardenia polysaccharide according to claim 1, characterized in that: The molecular weight of the gardenia polysaccharide ranges from 30 to 77.5 kDa.

4. The method for preparing Gardenia polysaccharide according to any one of claims 1 to 3, characterized in that: The gardenia polysaccharide is prepared according to the following steps: 1) crushing the dried gardenia into powder using a pulverizer, and defatting the powder in industrial ethanol to obtain defatted gardenia; 2) extracting the defatted gardenia in step 1) by boiling water extraction method for 4-6 times, then combining the extracts, concentrating to one fifth of the volume of the extracts, centrifuging to remove the precipitate, and retaining the supernatant; dialyzing the supernatant with running water for more than 72 hours, and then standing overnight; obtaining a polysaccharide precipitate after centrifugation, and drying at 60° C. to obtain a crude gardenia polysaccharide GP; 3) The crude Gardenia polysaccharide obtained in step 2) was dissolved in deionized water, stirred overnight, centrifuged, and the supernatant was loaded onto a DEAE SepharoseTM Fast Flow anion exchange column, and gradient eluted with deionized water, 0.1M, and 0.2M NaCl solutions in sequence, with the flow rate controlled at 100mL / min, and collected with an automatic collector; 20μL was taken from each tube, and the color was developed with sulfuric acid-phenol method and its absorbance was detected at 490nm with an enzyme marker, and the elution curve was drawn with absorbance and elution volume; the corresponding polysaccharide components were collected according to the elution curve, and then concentrated, dialyzed, and freeze-dried; another crude Gardenia polysaccharide was taken, and the polysaccharide was further separated and purified using the above method; finally, the polysaccharide components eluted twice with 0.1M NaCl were combined and named GP1; GP1 was dissolved in deionized water, centrifuged at 3500r / min for more than 10min, and the supernatant was loaded onto a Sephacryl S-200HR gel column, and 0.2M The product was eluted with NaCl solution at a flow rate of 0.3 mL / min, and the corresponding components were collected by an automatic collector. The elution curve was drawn using the sulfuric acid-phenol method, and the desired components were collected and concentrated, dialyzed, and freeze-dried to finally obtain Gardenia polysaccharide, which was named GP121.

5. The method for preparing Gardenia polysaccharide according to claim 4, characterized in that: In step 1), the dialysate used for running water dialysis is a mixture of the extract and 95% ethanol by volume in a volume ratio of 1:3-5.

6. Use of the Gardenia polysaccharide as claimed in claim 1 in the preparation of a drug for treating pulmonary fibrosis.

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