Rehmannia root extract, preparation method thereof and application of rehmannia root extract in preparation of medicine for preventing and treating gouty arthritis

Abstract

The invention discloses a radix rehmanniae extract, a preparation method thereof and application of the radix rehmanniae extract in preparation of medicines for preventing and treating gouty arthritis. The preparation method of the rehmannia root extract comprises the following steps: S1, adding water into rehmannia root for extraction to obtain a rehmannia root water extract; and S2, adding ethyl acetate into the rehmannia root water extract for extraction, and collecting an upper solution to obtain the rehmannia root extract. By constructing a rat gouty arthritis model, the result shows that the rehmannia root ethyl acetate extract has a certain treatment effect on gouty arthritis.

Description

Technical Field

[0001] The invention relates to the technical field of medicines, and in particular to a rehmannia root extract, a preparation method thereof and application of the extract in preparing medicines for preventing and treating gouty arthritis. Background Art

[0002] Gouty arthritis (GA) is a disease caused by purine metabolism disorder. The concentration of uric acid in the blood increases and urate (MSU) crystals are deposited in the joints. Its main clinical features are hyperuricemia, recurrent swelling of arthritis and pain in the surrounding joints. At present, nonsteroidal anti-inflammatory drugs, colchicine, glucocorticoids, etc. are often used in the clinical treatment of gouty arthritis to promote uric acid excretion and inhibit uric acid production. However, long-term use is prone to cause adverse reactions such as gastrointestinal reactions and liver and kidney damage. According to traditional Chinese medicine, the basic pathogenesis of gouty arthritis is spleen and stomach disharmony, liver and kidney deficiency, and internal obstruction of wind, cold, dampness, heat, phlegm and blood stasis, which causes pain in the limb meridians. Traditional Chinese medicine embodies the advantage of "holistic treatment" in the field of anti-gout, and effectively copes with various complications. In addition, traditional Chinese medicine has the advantages of good tolerance and low toxicity and side effects. Therefore, finding more effective and safer anti-gouty arthritis drugs has long been one of the research hotspots.

[0003] Rehmannia glutinosa Rehmannia glutinosa Libosch. Fresh or dried root tubers, mainly produced in Henan, Hebei, Shanxi and Shandong, with Henan as the authentic production area, are one of the four famous Huai medicines. "Shennong's Herbal Classic" says: "Rehmannia root is used to treat broken tendons, injuries, blood stasis, bone marrow and muscle growth", and is listed as a top grade. Rehmannia root has been used as a traditional Chinese medicine for thousands of years. It has the effects of lowering blood sugar, lowering uric acid, stopping bleeding, strengthening the heart, diuresis, anti-inflammatory, enhancing immunity and protecting the liver. According to different processing methods, it can be divided into three types: raw rehmannia root, fresh rehmannia root and cooked rehmannia root. Rehmannia root processed by different methods has different effects.

[0004] At present, the Rehmannia used in anti-gouty arthritis is mainly raw Rehmannia. The Chinese medicine composition for treating gouty arthritis disclosed in CN106177296A is composed of raw Rehmannia, Galla chinensis, Cortex phellodendri, Rhizoma corydalis, Cortex moutan, Radix clematis, Rhizoma alisma, Poria, Morus altissima, Acorus calamus, Arisaema strychnifolia, Semen nux vomica, Luffa, Raw licorice, Rubus idaeus, Viola yedoensis, Processed Pinellia, Borneolum, Mung bean powder, Caulis spatholobi, Caulis spatholobi, Sedum chinense, and Caulis dasyphyllae. The Chinese medicine for treating acute gouty arthritis disclosed in CN105770629A is composed of the following raw materials in a certain weight ratio: Smilax glabra, Radix schizonepetae, Radix scutellariae, Raw Rehmannia, Cortex phellodendri, Rhizoma cyrtonemae, Radix schizonepetae, Radix schizonepetae, Radix schizonepetae, Radix schizonepetae, Radix schizonepetae, Radix dasyphyllae, Radix schizonepetae, Radix corydalis, Radix tetrandrae, Herba plantaine, Atractylodes macrocephalae, Rhizoma coptidis, Radix coptidis, Radix peonye, ​​Radix paeoniae alba, and raw licorice. The ingredients of the anti-gouty arthritis Chinese medicine composition are complex.

[0005] Traditional extraction methods of Rehmannia glutinosa extracts mainly include water extraction, alcohol extraction and supercritical fluid extraction. The composition, structure and activity of the extracts obtained by different extraction reagents and extraction methods are also different, and their uses may also be very different. Therefore, finding a Rehmannia glutinosa extract that can be directly used for anti-gouty arthritis is of great significance for the development of anti-gouty arthritis drugs. Summary of the invention

[0006] The present invention aims to provide a Rehmannia root extract, a preparation method thereof and application thereof in the preparation of a medicine for preventing and treating gouty arthritis. The Rehmannia root extract is an ethyl acetate extract of a raw Rehmannia root water extract. A rat gouty arthritis model is constructed, and the results show that the raw Rehmannia root ethyl acetate extract has a certain therapeutic effect on gouty arthritis.

[0007] In a first aspect, the present invention provides a method for preparing a Rehmannia glutinosa extract, comprising the following steps: S1. adding water to Rehmannia root for extraction to obtain a raw Rehmannia root water extract; S2. Adding ethyl acetate to the Rehmannia glutinosa water extract for extraction, collecting the upper layer solution, and obtaining the Rehmannia glutinosa extract.

[0008] In the above-mentioned preparation method of Rehmannia glutinosa extract, as an example, the Rehmannia glutinosa is raw Rehmannia glutinosa.

[0009] In the above-mentioned preparation method of Rehmannia glutinosa extract, in the extraction step, the solid-liquid ratio is 1g: (10-20)mL (such as 1g: 10mL), the extraction temperature is 100°C, the extraction times are 2 times, and each extraction lasts 3h.

[0010] In the above-mentioned method for preparing the Rehmannia glutinosa extract, the volume ratio of the ethyl acetate to the Rehmannia glutinosa aqueous extract is 1:1; The extraction time is 0.5 to 1 h, such as 0.5 h.

[0011] In the above-mentioned preparation method of Rehmannia glutinosa extract, after the extraction in step S2, the following steps are further included: concentrating the upper layer solution under reduced pressure to form an extract; Preferably, the temperature of the reduced pressure concentration is 40-45°C, and the relative density of the extract at 20-25°C (such as 25°C) is 0.90-1.10 g / mL.

[0012] In a second aspect, the present invention provides a Rehmannia glutinosa extract obtained by any of the preparation methods described above.

[0013] In a third aspect, the present invention provides use of the Rehmannia glutinosa extract in the preparation of a medicament for preventing and / or treating gouty arthritis.

[0014] In the above application, the gouty arthritis is acute gouty arthritis.

[0015] In the above applications, the prevention and / or treatment includes any one of improving joint swelling, anti-inflammation, and improving joint pathological conditions.

[0016] In the above application, the anti-inflammatory method includes reducing the level of inflammatory factors in serum, and the inflammatory factors include IL-1β, NLRP3, and TNF-α; The improvement of joint pathological state is to reduce the inflammatory infiltration of joint synovial tissue.

[0017] In the present invention, the subject of drug treatment is human or mammal (such as rats, etc.). In the present invention, the dose of the Rehmannia glutinosa extract (ethyl acetate extract of Rehmannia glutinosa) of the present invention is 50-100 mg / kg / d (such as 50 mg / kg / d, 100 mg / kg / d) administered to GA rats by intragastric administration for 7 consecutive days.

[0018] In a fourth aspect, the present invention provides the use of the Rehmannia glutinosa extract in preparing a medicament for preventing and / or treating gout. Specifically, the medicament is used for treating gouty arthritis.

[0019] The present invention has the following beneficial effects: The present invention extracts the Rehmannia glutinosa water extract with ethyl acetate, and takes the upper solution and concentrates it under reduced pressure to obtain the Rehmannia glutinosa ethyl acetate extract. By establishing a rat acute gouty arthritis (GA) model, the changes in the rat's body mass index and ankle swelling index are observed, the uric acid and creatinine content in the rat serum and the activity of xanthine oxidase are detected, the IL-1β, NLRP3, and TNF-α content in the rat serum are determined, and the pathological tissue morphology of the rat ankle joint is observed. The results show that the Rehmannia glutinosa ethyl acetate extract can reduce the swelling degree of the ankle joint of GA rats, reduce the uric acid and creatinine content and the activity level of xanthine oxidase, reduce the IL-1β, NLRP3, and TNF-α content in the serum of GA rats, and reduce the inflammatory infiltration of the synovial tissue of the joints of GA rats. The Rehmannia glutinosa ethyl acetate extract of the present invention has a certain therapeutic effect on gouty arthritis, and the overall therapeutic effect is better than that of the Rehmannia glutinosa water extract. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a process flow chart for preparing the ethyl acetate extract of Rehmannia glutinosa in Example 1.

[0021] Figure 2 These are TIC diagrams of different Rehmannia glutinosa extracts under positive (+) and negative (-) ion modes in Example 1 of the present invention; Note: A: Rehmannia glutinosa water extract (RR); B: Rehmannia glutinosa ethyl acetate extract (RE).

[0022] Figure 3 This is a schematic diagram of the animal experiment process in Example 2 of the present invention.

[0023] Figure 4 The figure shows the effect of the Rehmannia glutinosa extract in Example 2 of the present invention on the body weight (A), kidney index (B) and liver index (C) of the GA rat model.

[0024] Figure 5 This is the effect of the Rehmannia glutinosa extract in Example 2 of the present invention on the degree of ankle swelling in a GA rat model.

[0025] Figure 6 The results are as follows: The effects of the Rehmannia glutinosa extract in Example 2 of the present invention on the serum uric acid content (A), serum creatinine content (B), xanthine oxidase activity in the liver (C), serum inflammatory factor IL-1β content (D), Effects of NLRP3 content in serum (E) and TNF-α content in serum (F).

[0026] Figure 7 This is the effect of the Rehmannia glutinosa extract in Example 2 of the present invention on the pathological tissue morphology of the ankle joint in a GA rat model. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with specific embodiments, and the examples provided are only for illustrating the present invention, rather than for limiting the scope of the present invention. The examples provided below can be used as a guide for further improvements by those of ordinary skill in the art, and do not constitute a limitation of the present invention in any way.

[0028] The methods used in the following examples, unless otherwise specified, are all conventional methods, carried out according to the techniques or conditions described in the literature in the art or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial sources.

[0029] The raw Rehmannia root in the following examples was purchased from Wuzhi County, Jiaozuo City, Henan Province, and dried at 60°C.

[0030] Monosodium urate crystals were purchased from Shanghai Yuanye Biotechnology Co., Ltd. with the catalog number S30640.

[0031] The uric acid test kit and creatinine test kit were purchased from Nanjing Jiancheng Bioengineering Research Institute Co., Ltd. with the catalog numbers C012-2-1 and C011-2-1, respectively.

[0032] Xanthine oxidase kit was purchased from Suzhou Gres Biotechnology Co., Ltd., G0139W.

[0033] Interleukin-1β (IL-1β), NOD-like receptor protein 3 (NLRP3), and rat tumor necrosis factor α (TNFα) enzyme-linked immunosorbent assay (ELISA) kits were purchased from Lunchangshuo Biotechnology Co., Ltd. with batch numbers E20240415-30206B, E20240415-34924B, and E20240415-31063B, respectively.

[0034] Avertin was purchased from Shanghai Duowo Biotechnology Co., Ltd. with the catalog number DW3106.

[0035] Example 1: Preparation of Rehmannia glutinosa ethyl acetate extract and composition analysis 1. Preparation method according to Figure 1 The process flow chart shown in the figure is used to prepare the ethyl acetate extract of Rehmannia glutinosa, and the specific steps are as follows: (1) Add 5000 mL of distilled water to 500 g of Rehmannia root at a solid-liquid ratio of 1:10 and boil for extraction. Extract for 3 h each time, repeat twice, and combine the extracts.

[0036] (2) Take 1000 mL of the raw Rehmannia extract, concentrate under reduced pressure, and freeze-dry to obtain the raw Rehmannia water extract (RR). The yield of the Rehmannia water extract (%) = the mass of the Rehmannia water extract / the mass of the dried Rehmannia.

[0037] (3) Take 4000mL of raw Rehmannia extract and add 4000mL of ethyl acetate for extraction. The extraction time is 0.5h. Take the upper layer solution and concentrate it under reduced pressure at 40-45℃ until the relative density of the extract at 25℃ is 0.90-1.10g / mL, and finally obtain raw Rehmannia glutinosa ethyl acetate extract (RE). Yield of Rehmannia glutinosa ethyl acetate extract (%) = mass of Rehmannia glutinosa ethyl acetate extract / mass of dried Rehmannia glutinosa.

[0038] 2. Composition Analysis UPLC-MS analysis Mobile phase: 0.1% formic acid aqueous solution (A)-acetonitrile (B), gradient elution (0-7min, 1%→22%B; 7-9min.22%→25%B; 9-16min, 25%→44%B; 16-20min, 44%→55%B; 20-30min, 55%→99%B), column temperature 40℃, flow rate 0.3mL / min, injection volume 2μL. Electrospray ion source (ESI) was used, positive and negative ions were collected simultaneously, the positive ion voltage was 3000V, the negative ion voltage was -3000V, and the drying gas flow rate was 10L·min -1 , ion source temperature 120°C, gas pressure 35psi.

[0039] The positive and negative ion full scans were performed on the Rehmannia glutinosa extract test solution to obtain the base peak scan chromatograms under positive and negative ion conditions (see Figure 2 ), Xcalibur software was used to process and analyze the mass spectrometry data, and the retention time, molecular formula, molecular weight of the target compound was combined with the secondary fragment ion information and related literature to match the possible compounds. There were 18 kinds of Rehmannia glutinosa water extracts, including 8 iridoid glycosides, 6 phenylethanoid glycosides, 1 nucleoside, and 2 other types. There were 14 kinds of Rehmannia glutinosa ethyl acetate extracts, including 6 iridoid glycosides, 5 phenylethanoid glycosides, 1 organic acid, and 2 other types (see Table 1, Table 2).

[0040] In the point spray positive and negative ion modes, dehydrogenated quasi-molecular ion peaks are generally detected for cyclopentadiene compounds. However, dehydrogenated quasi-molecular ion peaks are usually not the main signal in the positive ion mode. Their intensity is low and they are easily masked by other ion peaks. When the mobile phase contains formic acid, [M+HCOO] will also be generated for cyclopentadiene compounds with methoxyl groups at C-4. - When the mobile phase is acetic acid, [M+AcO] will be detected - When the quasi-molecular ion or adduct molecular ion of iridoid glycoside is used as the parent ion for fragmentation, the fragmentation pathway of the compound is usually the loss of neutral molecules H2O, CO2, Glu, etc., followed by the fragmentation of dihydropyran. For example, the quasi-ion peak of 8-epi-strychnine acid in negative ion mode is m / z 375.1298 [MH] - The molecular formula is estimated to be C 16 H 24 O 10 , M.S. 2 The spectrum shows that the quasi-ion peak loses the glucose residue (C6H 10 O 5， 162) forms m / z 213.0762 [MH-Glu] - The fragment continues to lose the carboxyl group to form CO2 to give m / z 169.0862 [MH-Glu-CO2] - The fragments, and the fragments continue to break off the hydroxyl group and remove H2O to form m / z 151.0751 [MH-Glu-CO2-H2O] - Fragment ions.

[0041] Phenylethanol glycosides are one of the main components of Rehmannia glutinosa, and their main structure is composed of phenylethanol, caffeic acid, glucose and rhamnose. The present invention detects a variety of phenylethanol glycoside compounds from Rehmannia glutinosa extracts. Taking verbascoside as an example, its quasi-ion peak in negative ion mode is m / z 623.1914 [MH]-, and the inferred molecular formula is C 29 H 36 O 15The MS2 spectrum shows that the quasi-ion peak loses the caffeoyl group, m / z 461.1426 [MH-caf]-fragment, which continues to lose the rhamnosyl group to obtain the [MH-caf-RHa]-fragment.

[0042] Table 1 Relative retention times and mass spectrometry data of chemical components in Rehmannia glutinosa aqueous extract (RR)

[0043] Table 2 Relative retention times and mass spectrometry data of chemical components in ethyl acetate extract (RE) of Rehmannia glutinosa

[0044] Example 2: Therapeutic effect on acute gouty arthritis in rats (1) Experimental animals Wister rats (male, 170-200 g) were provided by Liaoning Changsheng Biotechnology Co., Ltd. (License No.: SCXK (Liao) 2020-0001). The experimental animals were kept under circadian lighting conditions, with the temperature controlled at (25 ± 2) °C and the relative humidity controlled at 60%-70%. They were adaptively fed for one week before the experiment, with free access to water and ordinary feed. This experiment was carried out in accordance with the relevant provisions of the animal ethics requirements of Henan Agricultural University.

[0045] (2) Experimental methods and content 2.1 Preparation of acute gouty arthritis model, grouping and drug administration Thirty-six rats were randomly divided into six groups: control group (NC), model group (MSU crystal + NC), low-dose Rehmannia root water extract group (MSU crystal + RR-H (1.5 g / kg / d)), high-dose Rehmannia root water extract group (MSU crystal + RR-L (3 g / kg / d)), low-dose Rehmannia root ethyl acetate group (MSU crystal + RE-H (50 mg / kg / d)), and high-dose Rehmannia root ethyl acetate group (MSU crystal + RE-L (100 mg / kg / d). The modeling method was based on the literature "Benoit Banga N'guessan. Toxicity, mutagenicityand trace metal constituent of Termitomyces schimperi (Pat.) R. Heim(Lyophyllaceae) and kaolin, a recipe used traditionally in cancer managementin Cote d'Ivoire. Journal of Ethnopharmacology 276 (2021) 114147. " and "SuhailAnees, GC-MS analysis and potential therapeutic efficacy of extracts fromAllium humile Kunth in lowering dyslipidemia in wistar rat models. Journal ofEthnopharmacology 320 (2024) 117478.” Each group had 6 rats, and the rats were gavaged continuously for 7 days. The first 6 days were gavage according to the dosage of each group. On the 7th day, the rats were anesthetized with Avertin, and the ankle joints of the rats were disinfected with 70% alcohol. The blank group was injected with an equal amount of normal saline at the same site. One hour after gavage, the model group and the treatment group were injected with 0.1 mL of MSU suspension (100 mg / mL) along the dorsal side of the right ankle joint of the rat at 45°C. The MSU preparation process: 1g uric acid was dissolved in 200mL water containing 6mL 1mol / L NaOH, heated to dissolve, and the pH value was adjusted to 7.2 by HCl. The solution was stirred and cooled to room temperature, stored at 4°C overnight, and the precipitate was filtered with filter paper and dried at low temperature to obtain MSU crystals. The rats were killed on the 8th day, and the serum, liver, kidney and ankle joints of the rats were taken for subsequent detection (such as Figure 3 as shown).

[0046] 2.2 Liver, kidney and body mass index of rat GA model The rats were weighed before administration and on days 3, 5, 7, and 8 after administration. After the rats were killed, their livers and kidneys were separated and weighed. Liver index = liver weight / rat weight before death × 100%, kidney index = kidney weight / rat weight before death 100%.

[0047] The experimental results are as follows Figure 4 The analysis of rat body weight change index is shown in Figure 4 (A). From the overall trend of the rat body weight index, all groups showed an upward trend from 1st to 7th day. Compared with the drug-treated group and the control group, the body weight index of the model group increased more slowly. After the MSU suspension was injected into the ankle joint of the rats on the 7th and 8th day, the body weight of each group decreased, and the body weight of the model group decreased more significantly. Figure 4 As shown in (B, C), there are significant differences in the liver and kidney indexes between the model group and the control group, indicating that the model was successfully established. The criteria for successful modeling are: the corresponding ankle joint is significantly swollen after successful modeling, the walking movement is slower than that of the normal group, and the symptoms last for a certain period of time, which is consistent with the literature. There is no significant difference in the liver and kidney indexes of the drug administration group compared with the control group, indicating that the Rehmannia extract has no obvious side effects on the liver and kidneys of rats.

[0048] 2.3 Ankle swelling in rats In order to verify the improvement effect of Rehmannia extract on the pathological state of the ankle joint in the GA rat model, the ankle joint diameter of the rat was measured by the same person with a vernier caliper at the same position at 0h, 4h, 8h, 12h, and 24h before and after the injection of MSU suspension in the ankle joint, and the changes in swelling value were calculated. The ankle joint of each rat was measured three times at each time point. Ankle joint swelling value = 100% × (ankle joint diameter after injection of MSU suspension - ankle joint diameter before injection of MSU suspension) / ankle joint diameter before injection of MSU suspension.

[0049] The experimental results are as follows Figure 5 As shown. Comparing the knee joint swelling index, the model group had the highest swelling index and the blank group had the lowest swelling index, indicating that the model was successful, and the water extraction group (high) > water extraction group (low) > ethyl acetate group (high) > ethyl acetate group (low). Figure 5 It can be seen that the ankle swelling of each group reached the highest level 4 hours after modeling, and then decreased. Compared with the model group, the swelling of the drug-treated group was significantly reduced, among which the ethyl acetate extract of Rehmannia glutinosa (RE) had a better effect on alleviating ankle swelling.

[0050] 2.4 Determination of uric acid and creatinine levels and xanthine oxidase activity in rats Rat plasma was collected and centrifuged at 4000 r / min at 4°C. The supernatant was collected and the uric acid and creatinine contents in rat serum were detected according to the instructions of the uric acid and creatinine test kits. The xanthine oxidase activity in rat liver was detected according to the instructions of the xanthine oxidase test kit.

[0051] The experimental results are as follows Figure 6 As shown in (A, B, C), compared with the control group, the uric acid level of uric acid and creatinine content and xanthine oxidase activity of rats in the model group were significantly increased. Compared with the model group, the ethyl acetate group had the best effect on these biochemical indicators in the drug administration group.

[0052] 2.5 ELISA detection of IL-1β, NLRP3, and TNF-α levels in rat serum Serum was collected for the determination of IL-1β, NLRP3, and TNF-α levels, and the operating procedures were strictly carried out according to the instructions of the ELISA kit.

[0053] The experimental results are as follows Figure 6 As shown in (D, E, and F), compared with the control group, the levels of inflammatory factors IL-1β, NLRP3, and TNF-α in the serum of rats in the model group were significantly increased, the level of IL-1β in the drug-treated group was significantly decreased compared with the model group, the level of NLRP3 in the low-dose Rehmannia glutinosa water extract group (RR-L) was significantly decreased compared with the model group, and the level of TNF-α in the drug-treated group was also decreased compared with the model group.

[0054] 2.6 Detection of rat ankle pathological tissue morphology by hematoxylin-eosin (HE) staining The rats were anesthetized and killed, and their ankle joints were fixed in paraformaldehyde fixative. After fixation, they were dehydrated and decalcified, and then embedded. Paraffin sections were made, stained with H&E, and observed under an optical microscope.

[0055] Figure 7The results showed that the epithelial cells in the inner layer of the synovial tissue of the blank group were arranged neatly, the synovial connective tissue was loose, no obvious connective tissue hyperplasia and inflammatory cell infiltration were observed; the ankle joint structure was clear, the joint cavity was clean, the cartilage surface was smooth, the number of chondrocytes was abundant, the morphology and structure were normal, and the arrangement was regular. Compared with the blank group, the synovial tissue of the model group showed moderate hyperplasia of connective tissue in a medium range, edema in a small range, loose connective tissue arrangement, and a large number of inflammatory cells mainly lymphocytes scattered infiltration, and a small amount of necrotic cell fragments were observed. Compared with the model group, the high-dose raw rehmannia water extract group (RR-H) had relatively less inflammatory cell infiltration, mainly lymphocytes and granulocytes, accompanied by a small amount of necrotic cell fragments; the low-dose raw rehmannia water extract group (RR-L) had significant improvement, with a decrease in inflammatory cells; the high-dose raw rehmannia ethyl acetate group (RE-H) had a small amount of inflammatory infiltration of lymphocytes and granulocytes, and focal hemorrhage was visible, the ankle joint structure was clear, and the chondrocytes were arranged regularly; the degree of inflammatory cell infiltration in the low-dose raw rehmannia ethyl acetate (RE-L) group was significantly improved compared with the model group.

[0056] In summary, compared with the raw Rehmannia glutinosa water extract, the raw Rehmannia glutinosa ethyl acetate extract of the present invention has a better therapeutic effect on gouty arthritis, and its mechanism of action can reduce the activity level of xanthine oxidase, reduce the contents of IL-1β, NLRP3, and TNF-α in the serum of GA rats, and then reduce the contents of uric acid and creatinine in the serum, thereby improving the joint swelling and pathological tissue morphology of gouty arthritis.

[0057] The present invention has been described in detail above. For those skilled in the art, without departing from the purpose and scope of the present invention, can implement the present invention in a wider range under equivalent parameters, concentrations and conditions. Although the present invention provides specific embodiments, it should be understood that the present invention can be further improved. In a word, according to the principle of the present invention, the application is intended to include any changes, uses or improvements to the present invention, including departing from the disclosed scope in the application and the changes made with conventional techniques known in the art.

Claims

1. A method for preparing a Rehmannia glutinosa extract, comprising the following steps: S1. adding water to Rehmannia root for extraction to obtain Rehmannia root water extract; S2. Adding ethyl acetate to the Rehmannia glutinosa water extract for extraction, collecting the upper layer solution, and obtaining the Rehmannia glutinosa extract.

2. The method for preparing the Rehmannia glutinosa extract according to claim 1, characterized in that: In the extraction step, the material-liquid ratio is 1 g: (10-20) mL, the extraction temperature is 100° C., the extraction times are 2 times, and each extraction time is 3 hours.

3. The method for preparing the Rehmannia glutinosa extract according to claim 1 or 2, characterized in that: The volume ratio of the ethyl acetate to the Rehmannia root water extract is 1:1; The extraction time is 0.5 to 1 h.

4. The method for preparing the Rehmannia glutinosa extract according to any one of claims 1 to 3, characterized in that: After the extraction in step S2, the following steps are further included: concentrating the upper layer solution under reduced pressure to form an extract; Preferably, the temperature of the reduced pressure concentration is 40-45°C, and the relative density of the extract at 20-25°C is 0.90-1.10 g / mL.

5. The Rehmannia glutinosa extract obtained by the preparation method according to any one of claims 1 to 4.

6. Use of the Rehmannia glutinosa extract according to claim 5 in the preparation of a medicament for preventing and / or treating gouty arthritis.

7. The use according to claim 6, characterized in that: The gouty arthritis is acute gouty arthritis.

8. The use according to claim 6 or 7, characterized in that: The prevention and / or treatment includes any one of improving joint swelling, anti-inflammation, and improving joint pathological conditions.

9. The use according to claim 8, characterized in that: The anti-inflammatory treatment includes reducing the level of inflammatory factors in serum, and the inflammatory factors include IL-1β, NLRP3, and TNF-α; The improvement of joint pathological state is to reduce the inflammatory infiltration of joint synovial tissue.

10. Use of the Rehmannia glutinosa extract according to claim 5 in the preparation of a medicament for preventing and / or treating gout.

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