Lactobacillus plantarum LP-SG7, afterbiogen, composition and application

Abstract

The invention relates to a lactobacillus plantarum LP-SG7, a postbiotics, a composition and application. The lactobacillus plantarum LP-SG7 provided by the invention is high in biological activity and can tolerate gastric acid and cholate. The lactobacillus plantarum LP-SG7 or the composition containing the viable bacteria of the lactobacillus plantarum LP-SG7 and the metagenic powder described in the invention can significantly reduce the content of blood uric acid, urea nitrogen and creatinine in a model mouse with oteracil potassium induced hyperuricemia, and reduce the content of xanthine oxygen in liver tissues.

Description

Technical Field

[0001] This article relates to the field of microbial technology, and in particular to a Lactobacillus plantarum LP-SG7 with uric acid-lowering effects, and its postbiotics and uses. Background Art

[0002] Uric acid is the end product of purine metabolism in the human body. Excessive intake of high-purine foods, abnormal purine metabolism, and decreased kidney function can all lead to hyperuricemia. Hyperuricemia can lead to the accumulation of urate in joints and surrounding tissues, causing gout and other complications such as chronic kidney disease, hypertension, and cardiovascular disease. In my country, gout is predominantly found in relatively affluent coastal areas such as the Bohai Rim, the Yangtze River Delta, and the Pearl River Delta, largely due to the local population's dietary habits. According to the 2017 White Paper on the Current Status of Gout in China, there are currently 170 million people with hyperuricemia in China, including over 80 million with gout, and this number is growing rapidly at an annual rate of 9.7%. Gout has become the second most common metabolic disease in my country, second only to diabetes, posing a serious threat to public health. Currently, there is a lack of effective long-term interventions for the control of uric acid levels in the blood. There are generally two sources of uric acid in human blood: one is the purine in the food consumed. The amount of purine consumed is directly related to the uric acid concentration in the human blood. Part of the exogenous purine compounds are metabolized by Escherichia coli that secretes xanthine deaminase in the intestine to form uric acid, which is then absorbed by the body; the other is endogenous purine metabolism. Two-thirds of the endogenously formed uric acid is excreted through the kidneys, and the remaining one-third is excreted through the intestines. Some of the excreted uric acid will be reabsorbed by the intestines through transport proteins. Therefore, increasing the decomposition and excretion of uric acid in the intestine is a potential feasible way to lower blood uric acid.

[0003] Currently, allopurinol is widely used in clinical practice to control hyperuricemia, but there is still controversy over whether it can provide kidney function protection. Probiotics have become a hot research field in recent years due to their functions such as adjusting intestinal function and anti-tumor. In recent years, sequencing analysis of fecal microbial flora of gout patients at home and abroad has found that the intestinal flora structure of gout patients has changed significantly compared with normal people. Some studies have shown that lactic acid bacteria and Pseudomonas in the intestine can improve the decomposition of uric acid in the intestine. Therefore, using probiotics to improve the structure of the intestinal flora to reduce uric acid in the blood and the inflammatory response caused by uric acid to achieve the therapeutic effect of treating hyperuricemia-induced kidney damage is undoubtedly of great clinical significance for the treatment of hyperuricemia patients. Summary of the Invention

[0004] Based on the above background, the present application provides a Lactobacillus plantarum LP-SG7 with uric acid-lowering function, wherein the classification name of the Lactobacillus plantarum LP-SG7 is Lactobacillus Plantarum, and the preservation number is CGMCC No. 29702.

[0005] The Lactobacillus plantarum LP-SG7 provided in this application was obtained by screening the original strain of Lactobacillus plantarum LP-SG9 isolated from commercial kimchi through ultraviolet mutagenesis for 30 generations. It was deposited at the General Microbiology Center of the China Culture Collection Administration on January 22, 2024, with the microbial deposit number CGMCC No. 29702; the deposit address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. Its morphological characteristics are: it grows well on MRS agar medium, with medium-sized colonies, milky white, upwardly convex, round, with irregular edges and a relatively rough surface. It is Gram-positive, and the cells are rod-shaped under a microscope, without flagella, and do not produce spores.

[0006] On the other hand, the present application also provides a postbiotic powder prepared by the Lactobacillus plantarum LP-SG7 described herein.

[0007] In another aspect, the present application also provides a method for preparing the postbiotic powder described herein, the method comprising the following steps:

[0008] 1) inoculating the Lactobacillus plantarum LP-SG7 described herein onto MRS medium for activation;

[0009] 2) preparing a bacterial suspension or liquid seed of the activated Lactobacillus plantarum LP-SG7 and inoculating it into a fermentation medium at an inoculum size of 5%, and fermenting it at a temperature of 30-40° C. under anaerobic or facultative anaerobic stirring conditions for 10-18 hours to obtain a live bacterial fermentation liquid after fermentation is completed;

[0010] 3) The live bacteria fermentation liquid is subjected to high temperature inactivation treatment and spray-dried to obtain the postbiotic powder.

[0011] On the other hand, the present application also provides a composition comprising the live bacteria of Lactobacillus plantarum LP-SG7 described herein and the postbiotic powder described herein.

[0012] On the other hand, the present application also provides use of the Lactobacillus plantarum LP-SG7 described herein, the postbiotic powder described herein, or the composition described herein in the preparation of a medicament for alleviating hyperuricemia.

[0013] On the other hand, the present application also provides the use of Lactobacillus plantarum LP-SG7 described herein, the postbiotic powder described herein, or the composition described herein in preparing a food or health product for alleviating hyperuricemia.

[0014] The Lactobacillus plantarum LP-SG7 provided herein has high biological activity and is tolerant to gastric acid and bile salts. Lactobacillus plantarum LP-SG7 or a composition comprising live bacteria of Lactobacillus plantarum LP-SG7 and the postbiotic powder described herein can significantly reduce blood uric acid, urea nitrogen, and creatinine levels in mice with potassium oxonate-induced hyperuricemia, and reduce xanthine oxygen content in liver tissue.

[0015] Other features and advantages of the present application will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present application. Other advantages of the present application can be realized and obtained by the solutions described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0017] Figure 1 This is a colony morphology diagram of Lactobacillus plantarum LP-SG7 provided in this application.

[0018] Figure 2 This is an optical microscope image of Lactobacillus plantarum LP-SG7 provided in this application.

[0019] Figure 3 This is a growth curve diagram of Lactobacillus plantarum LP-SG7 provided in this application. DETAILED DESCRIPTION

[0020] Unless otherwise indicated, the technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs. When a certain amount, concentration or other value or parameter is expressed in the form of a range, a preferred range, or a preferred upper numerical limit and a preferred lower numerical limit, it should be understood that it is equivalent to specifically revealing any range by combining any pair of upper range limits or preferred numerical values ​​with any lower range limit or preferred numerical value, without considering whether the range is specifically revealed. Unless otherwise indicated, the numerical ranges listed herein are intended to include the endpoints of the range and all integers and fractions (decimals) within the range.

[0021] The terms "about" and "approximately" when used in conjunction with a numerical variable generally refer to the value of that variable and all values ​​of that variable are within experimental error (e.g., within a 95% confidence interval for the mean) or within ±10% of the stated value, or wider.

[0022] The expression "comprising" or its synonyms "including," "containing," and "having" are open-ended and do not exclude additional unrecited elements, steps, or ingredients. The expression "consisting of excludes any elements, steps, or ingredients not specified. The expression "consisting essentially of" means that the scope is limited to the specified elements, steps, or ingredients, plus any optional elements, steps, or ingredients that do not materially affect the basic and novel characteristics of the claimed subject matter. It should be understood that the expression "comprising" encompasses the expressions "consisting essentially of" and "consisting of."

[0023] The expression "at least one" or "one or more" means 1, 2, 3, 4, 5, 6, 7, 8, 9 or more.

[0024] The present application provides a Lactobacillus plantarum LP-SG7 having a uric acid-lowering function, wherein the classification name of Lactobacillus plantarum LP-SG7 is Lactobacillus Plantarum, and the preservation number is CGMCC No. 29702.

[0025] On the other hand, the present application also provides a postbiotic powder prepared by the Lactobacillus plantarum LP-SG7 described herein.

[0026] In another aspect, the present application also provides a method for preparing the postbiotic powder described herein, comprising the following steps:

[0027] 1) inoculating the Lactobacillus plantarum LP-SG7 described herein onto MRS medium for activation;

[0028] 2) preparing a bacterial suspension or liquid seed of the activated Lactobacillus plantarum LP-SG7 and inoculating it into a fermentation medium at an inoculum size of 5%, and fermenting it at a temperature of 30-40° C. under anaerobic or facultative anaerobic stirring conditions for 10-18 hours to obtain a live bacterial fermentation liquid after fermentation is completed;

[0029] 3) The live bacteria fermentation liquid is subjected to high temperature inactivation treatment and spray-dried to obtain postbiotic powder.

[0030] In some embodiments, in step 3), the concentration of live bacteria in the live bacteria fermentation broth is greater than 10 11 cfu / ml; preferably, the concentration of live bacteria in the live bacteria fermentation broth is 10 11 -10 12 cfu / ml.

[0031] In some embodiments, in step 3), the high temperature inactivation treatment is performed at a temperature of 55° C. to 80° C., and for a time of 0.5 h to 3 h.

[0032] In another aspect, the present application also provides a composition comprising live bacteria of Lactobacillus plantarum LP-SG7 described herein and the postbiotic powder described herein. In some embodiments, the composition is also referred to as a postbiotic composition or a postbiotic composition containing Lactobacillus plantarum LP-SG7.

[0033] In some embodiments, the mass ratio of live Lactobacillus plantarum LP-SG7 to postbiotic powder is 1:1-1:4.

[0034] In another aspect, the present application also provides a probiotic composition comprising Lactobacillus plantarum LP-SG7 described herein and other probiotics. The other probiotics in the probiotic composition are selected from one or more of the following: Bifidobacterium, Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus gasseri, Lactobacillus rhamnosus, Lactobacillus salivarius, Lactobacillus crispatus, Lactobacillus fermentum, and Lactobacillus casei.

[0035] On the other hand, the present application also provides use of the Lactobacillus plantarum LP-SG7 described herein, the postbiotic powder described herein, or the composition described herein in the preparation of a medicament for alleviating hyperuricemia.

[0036] In another aspect, the present application also provides use of the Lactobacillus plantarum LP-SG7 described herein, the postbiotic powder described herein, or the composition described herein in the preparation of a medicament for treating or preventing hyperuricemia.

[0037] In some embodiments, a medicament comprises Lactobacillus plantarum LP-SG7 as described herein, a pharmaceutical carrier, and / or a pharmaceutical excipient. Pharmaceutical carriers include microcapsules, microspheres, nanoparticles, and / or liposomes; pharmaceutical excipients include excipients and / or additives. In some embodiments, excipients include binders, fillers, disintegrants, and / or lubricants; additives include solubilizers, cosolvents, cosolvents, and / or preservatives. In some embodiments, the medicament is in the form of a powder, granules, capsule, tablet, pill, or oral solution.

[0038] In another aspect, this application also provides the use of the Lactobacillus plantarum LP-SG7 described herein, the postbiotic powder described herein, or the composition described herein in the preparation of a food or health product for alleviating hyperuricemia. In some embodiments, the food is a health food; or the food includes dairy products, soy products, meat products, or fruit and vegetable products; or the food is a beverage or snack. In some embodiments, the food comprises the Lactobacillus plantarum LP-SG7 described herein and an edible supplement.

[0039] The present application also provides a safe and effective application of Lactobacillus plantarum LP-SG7 and a postbiotic composition containing Lactobacillus plantarum LP-SG7 in alleviating hyperuricemia, which can significantly reduce the blood uric acid, urea nitrogen and creatinine levels of mice with hyperuricemia induced by potassium oxonate, and reduce the xanthine oxygen content in liver tissue.

[0040] This application describes multiple embodiments, but this description is exemplary rather than restrictive, and it will be apparent to those skilled in the art that more embodiments and implementations may be included within the scope of the embodiments described herein. Although many possible feature combinations are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature of any embodiment may be used in combination with any other feature in any other embodiment, or may replace any other feature in any other embodiment.

[0041] This application includes and contemplates combinations of features known to those of ordinary skill in the art. The embodiments and features disclosed in this application may also be combined with any conventional features to form a unique inventive solution defined by the claims. Any feature of any embodiment may also be combined with features from other inventive solutions to form another unique inventive solution defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in this application may be implemented individually or in any appropriate combination. Therefore, the embodiments are not subject to other limitations except as provided in the appended claims and their equivalents. In addition, various modifications and changes may be made within the scope of protection of the appended claims.

[0042] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps in the specific order described. As will be understood by those skilled in the art, other orders of steps are also possible. Therefore, the specific order of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to performing their steps in the order written, and those skilled in the art can readily understand that these orders can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0043] The experimental methods in the following examples, for which specific conditions are not specified, are generally determined in accordance with national standards. The experimental materials in the following examples, for which the sources are not specified, are all commercially available raw materials. The equipment used in each step in the following examples is all conventional equipment. If there are no corresponding national standards, the methods are carried out in accordance with general international standards, conventional conditions, or conditions recommended by the manufacturer. Unless otherwise defined or indicated, all professional and scientific terms used in this application have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein can be applied to the methods of this application.

[0044] Culture medium used in the examples:

[0045] MRS solid medium: peptone 10 g / L, beef extract 10 g / L, yeast extract 5 g / L, dipotassium hydrogen phosphate 3 g / L, diammonium hydrogen citrate 5 g / L, sodium acetate 3 g / L, glucose 30 g / L, Tween-80 10 mL / L, MgSO4·7H2O 0.58 g / L, MnSO4·4H2O 0.25 g / L, calcium carbonate 0.01 g / L, adjust the pH to 6.0-6.5, sterilize at 121°C for 20 min and use.

[0046] MRS liquid culture medium: peptone 10 g / L, beef extract 10 g / L, yeast extract 5 g / L, diamine citratum 2 g / L, sodium acetate 5 g / L, glucose 30 g / L, Tween-80 5 ml / L, MgSO4·7H2O 0.58 g / L, MnSO4·4H2O 0.25 g / L, adjust pH to 6.5, sterilize at 121°C for 20 min and use.

[0047] Example

[0048] Example 1. Mutagenesis of strains with uric acid-lowering function

[0049] 1. Isolation of Lactobacillus plantarum LP-SG9:

[0050] Microbial screening samples were collected from kimchi purchased from different manufacturers on the market. The collected samples were added to a 1:1 sterile saline solution and ground with a juicer. 1 ml was weighed and placed in 9 ml of sterile saline. After thorough shaking and mixing, the mixture was diluted 10-fold and spread on MRS solid culture medium. The mixture was cultured at 37°C for 24-72 hours. Strains with a calcium-dissolving ring were selected by visual observation and repeatedly streaked for purification and culture. The strain was identified as Lactobacillus plantarum by 16s rDNA and named LP-SG9. The bacterium was deposited at the General Microbiology Center of the China Culture Collection Administration on March 3, 2021, with the microbial deposit number CGMCC No. 21863.

[0051] 2. UV mutagenesis and screening:

[0052] Using Lactobacillus plantarum LP-SG9 as the starting strain, ultraviolet mutagenesis was performed: the UV wavelength was 200-300nm, the irradiation distance was 15-30cm, and the irradiation time was 15s. After 30 generations of mutagenesis, a strain with visible bacterial mutation was screened out and named LP-SG7. The taxonomic name is Lactobacillus plantarum. It was deposited with the General Microbiology Center of the China Microorganism Culture Collection on January 22, 2024, with the microbial deposit number CGMCC No. 29702; the deposit address is No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing. This strain was tested for growth ability, acid and choline resistance, and gastrointestinal fluid ability. The results showed that this strain has significant advantages over the original strain LP-SG9 in these aspects. In addition, Lactobacillus plantarum LP-SG7 has the ability to lower uric acid, which the original strain LP-SG9 does not have.

[0053] Morphological observation of Lactobacillus plantarum LP-SG7:

[0054] The purified Lactobacillus plantarum LP-SG7 was diluted and spread on MRS agar medium, and then incubated at 37℃ for 48h to observe the colony morphology of the strain. Figure 1 As shown: The strain grew well on MRS solid medium, with medium-sized, milky white, upward-convex, round colonies with irregular edges; Gram staining was positive ( Figure 2 ), rod-shaped under the microscope ( Figure 2 ).

[0055] Example 2. Growth ability of Lactobacillus plantarum LP-SG7

[0056] Lactobacillus plantarum LP-SG7 was inoculated onto MRS solid medium and cultured at 37°C for 24 hours for activation, and then cultured in MRS liquid medium at a 5% inoculum volume for 20 hours to form a seed solution; 15% of the seed solution was inoculated into MRS liquid fermentation medium, and the culture was statically cultured at 37°C in a 7L fermenter, with samples taken every hour to measure OD600; a growth curve was drawn with time as the horizontal axis and absorbance value OD600 as the vertical axis. The growth curve of Lactobacillus plantarum LP-SG7 strain is shown in FIG. Figure 3 shown.

[0057] from Figure 3 It can be seen that the bacteria grew rapidly, with OD600 reaching 26 at 10 h and a maximum OD value of 41.12 at 17 h, indicating that Lactobacillus plantarum LP-SG7 entered a rapid growth phase at 6 h to 16 h and reached a stable phase at 16 h to 19 h, making it suitable for industrial production.

[0058] Example 3. Test of acid and bile salt resistance of Lactobacillus plantarum LP-SG7

[0059] Bile salt tolerance test:

[0060] Lactobacillus plantarum LP-SG7 and LP-SG9 were inoculated onto MRS solid medium and cultured at 37°C for 24 h for activation. They were then cultured in MRS liquid medium at a 5% inoculum volume for 20 h to form seed solution. The solution was centrifuged at 8000 r / min for 20 min, the cells were collected, and the precipitate was diluted with sterile saline to form 10 9 cfu / ml bacterial suspension.

[0061] Dissolve 0.1g, 0.2g, 0.3g, 0.4g and 0.5g of ox bile salt in 10mL of distilled water, filter and sterilize with a sterile microporous filter membrane (0.22μm), add 90mL of MRS liquid culture medium, and prepare 100mL of MRS culture medium containing 0.1%, 0.2%, 0.3%, 0.4% and 0.5% bile salt. Inoculate the bacterial suspension with 10% inoculum, mix well, and culture at 37℃ and 180r / min. Take 100ul of bacterial solution at 0h, 2h, 4h and 6h, dilute it with physiological saline, and take 100ul of 10 -5 -10 -6 The gradient dilutions were evenly spread on MRS solid medium and cultured anaerobically at 35°C for 48 hours. The colonies were counted and cultured in conventional MRS liquid medium as a control group. The survival rate of Lactobacillus plantarum LP-SG7 was calculated using the following formula:

[0062]

[0063] The results are shown in Tables 1 and 2.

[0064] Table 1 Survival rate of Lactobacillus plantarum LP-SG7 at different ox bile salt concentrations (%)

[0065]

[0066] Table 2 Survival rate of Lactobacillus plantarum LP-SG9 at different ox bile salt concentrations (%)

[0067]

[0068] By comparing the two strains, it can be seen that the choline resistance of Lactobacillus plantarum LP-SG7 is significantly improved compared with the original strain LP-SG9.

[0069] Acid resistance test:

[0070] Similarly, Lactobacillus plantarum LP-SG7 and LP-SG9 seed liquids were inoculated into MRS liquid culture medium with different pH values ​​(pH 1.0, 3.0, 5.0) at a 15% inoculum volume, mixed, and cultured at 37°C and 180 r / min. 100 μl of 10-5 ~10 -6 The gradient dilutions were evenly spread on MRS solid medium and cultured anaerobically at 37°C for 48 hours. The colonies were counted and cultured in conventional MRS liquid medium as a control group. The survival rate of Lactobacillus plantarum LP-SG7 was calculated using the following formula:

[0071]

[0072] Table 3 Survival rate of Lactobacillus plantarum LP-SG7 under acidic conditions

[0073]

[0074] Table 4 Survival rate of Lactobacillus plantarum LP-SG9 under acidic conditions

[0075]

[0076] The results are shown in Tables 3 and 4. The above data show that Lactobacillus plantarum LP-SG7 has a higher survival rate than Lactobacillus plantarum LP-SG9 in an environment of pH 1.0.

[0077] Example 4. Gastrointestinal fluid tolerance test of Lactobacillus plantarum LP-SG7

[0078] Preparation of artificial gastric juice:

[0079] Accurately measure 16.4 mL of hydrochloric acid with a mass concentration of 100 g / L, dilute it to 800 mL with distilled water, adjust the pH to 2.5, add 3.2 g of pepsin and 1.8 g of NaCl in sequence, make the volume to 1 L, filter and sterilize for later use.

[0080] Preparation of artificial intestinal fluid:

[0081] Weigh 6.8g KH2PO4 and add 800ml distilled water to dissolve it. Then weigh 10g trypsin and dissolve it in the KH2PO4 solution. Adjust the pH to 7.5 with 40g / L NaOH solution, filter and sterilize it for later use.

[0082] The Lactobacillus plantarum LP-SG7 seed solution in Example 2 was centrifuged at 8000 r / min for 20 min, the cells were collected, and the precipitate was diluted with sterile saline to form 10 9 cfu / ml bacterial suspension.

[0083] One ml of the Lactobacillus plantarum LP-SG7 and LP-SG9 bacterial suspension was added to a reaction tube containing 9 ml of artificial gastric fluid and incubated at 180 rpm at 37°C for 2 hours to simulate human gastric motility in vitro. One ml of the gastric fluid-treated bacterial suspension was added to a reaction tube containing 9 ml of artificial intestinal fluid and incubated at 180 rpm at 37°C for 0 and 3 hours to simulate intestinal motility. 100 μL of the reaction solution obtained after 0 and 2 hours of exposure to artificial gastric fluid and 0 and 3 hours of exposure to artificial intestinal fluid was extracted and serially diluted. The suspension was inoculated onto MRS solid medium in triplicate. After 24 hours of incubation at 37°C, viable bacteria were counted, and a control group was cultured on standard MRS liquid medium.

[0084] The calculation formula is:

[0085] The results are shown in Tables 5 and 6. According to the data, Lactobacillus plantarum LP-SG7 has relatively better gastrointestinal tolerance than Lactobacillus plantarum LP-SG9.

[0086] Table 5 Survival rate of Lactobacillus plantarum LP-SG7 gastrointestinal tract simulation (%)

[0087]

[0088] Table 6 Survival rate (%) of Lactobacillus plantarum LP-SG9 gastrointestinal tract simulation

[0089]

[0090] Example 5. Preparation of Lactobacillus plantarum LP-SG7 postbiotics

[0091] The preparation method of Lactobacillus plantarum LP-SG7 postbiotics comprises the following steps:

[0092] (1) Lactobacillus plantarum LP-SG7 was inoculated on MRS solid medium for activation;

[0093] (2) The activated Lactobacillus plantarum LP-SG7 was prepared into a bacterial suspension or liquid seed and inoculated into a fermentation medium in a 120 L tank at a 5% inoculum size. The fermentation was carried out at 37 ° C and nitrogen was introduced for 16 h. After the fermentation was completed, the number of viable bacteria was 1 × 10 11 cfu / ml of fermentation broth;

[0094] (3) The fermentation liquid was inactivated at 60°C for 1 hour and then spray-dried to obtain postbiotic powder.

[0095] Example 6. Determination of the ability of Lactobacillus plantarum LP-SG7 to degrade nucleotides

[0096] Lactobacillus plantarum LP-SG7 and LP-SG9 were inoculated onto MRS solid medium and cultured at 37°C for 24 hours for activation. A 5% inoculum volume was then added to MRS liquid medium for 20 hours to form a seed solution. 15% of the seed solution was inoculated into MRS liquid fermentation medium and cultured in a 7L fermenter at 37°C for 20 hours to obtain a fermentation broth. The fermentation broth was centrifuged at 8000 r / min for 20 minutes, and the supernatant and bacterial cells were collected. The precipitate was diluted with sterile saline to form a 10 9 cfu / ml bacterial suspension.

[0097] Resuspend 1 ml of Lactobacillus plantarum LP-SG7 and LP-SG9 suspensions with 1 ml of 0.5 g / L adenosine and 0.5 g / L guanosine, respectively, and incubate at 37°C with shaking at 200 rpm for 2 hours. Centrifuge at 6000 rpm for 5 minutes at 4°C. Terminate the reaction by mixing 900 μL of the supernatant with 100 μL of 0.1 mol / L perchloric acid. After filtering through a 0.22 μL sterile filter, a 20 μL aliquot was analyzed by high-performance liquid chromatography.

[0098] A Sunfire reverse phase chromatography column (5 μm, 4.6 mm × 250 mm) was used, with methanol as mobile phase A and 20 mmol / L NaH2PO4 (pH 2.5) as mobile phase B. The mobile phase elution gradient was as follows: 4% A to 6% A from 0 to 10 min; 6% A to 7% A from 10 to 20 min. The flow rate was 1 mL / min, the column temperature was 25°C, and detection was performed at a wavelength of 254 nm. A standard curve for adenosine and guanosine was used for quantification using the external standard method. Three replicates were performed, and data are presented as mean ± standard error. The degradation rate of purines (adenosine and guanosine) by Lactobacillus plantarum LP-SG7 was calculated using the following formula:

[0099]

[0100] The results are shown in Table 7. Adenosine and guanosine are precursors of uric acid in purine metabolism. The degradation rates of adenosine and guanosine by Lactobacillus plantarum LP-SG7 confirm the degradation rate of uric acid by Lactobacillus plantarum LP-SG7. According to the data, the degradation rate of adenosine and guanosine by Lactobacillus plantarum LP-SG7 is higher than that of LP-SG9, which means that it has a certain ability to lower uric acid.

[0101] Table 7 Degradation rate of adenosine and guanosine by Lactobacillus plantarum LP-SG7 and LP-SG9 in vitro (%)

[0102]

[0103]

[0104] Example 7. In vivo experiments of Lactobacillus plantarum LP-SG7 and its postbiotic composition

[0105] The composition of this embodiment comprises live Lactobacillus plantarum LP-SG7 bacteria and postbiotics prepared from Lactobacillus plantarum LP-SG7, wherein the ratio of live Lactobacillus plantarum LP-SG7 bacteria to postbiotics is 1:4.

[0106] Composition for the determination of serum uric acid (UA), serum urea nitrogen (BUN), creatinine (Cr), and xanthine oxidase (XOD)

[0107] ① Experimental materials

[0108] SD rats: Liaoning Changsheng Biotechnology Co., Ltd.

[0109] Basic feed: Liaoning Changsheng Biotechnology Co., Ltd.

[0110] Forty SD rats (200±20) g, aged 2-3 weeks, were selected and housed at a temperature of 24±1°C and a relative humidity of 60±5%, maintaining a 12-h day-night cycle. All rats were adapted to a normal diet for 7 days.

[0111] The fermentation broth of Example 6 was centrifuged at 8000 r / min for 20 min, the supernatant was removed, the cells were collected, washed twice with physiological saline, and resuspended into a bacterial concentration of 10 10 1 ml of the bacterial suspension was mixed with 4 g of the postbiotics from Example 5 to form a composition.

[0112] ②Modeling and grouping

[0113] Forty SD rats were randomly divided into five groups: a control group (CON), a model group (HUA), a Lactobacillus plantarum LP-SG7 interference group (Z1), a Lactobacillus plantarum LP-SG7 live bacteria and postbiotic combination interference group (Z2), and a positive control allopurinol group (Z3). Modeling was initiated. The eight rats in the control group were fed a normal diet with free access to water. Except for the control group, the remaining groups were fed a high-purine diet with free access to water and received an abdominal injection of potassium oxonate (250 mg / kg / day) for 7 consecutive days to establish a hyperuricemia model. From day 8 to day 21, the control and model groups were gavaged daily with 2 ml of normal saline; the Z1 group was gavaged daily with 0.52 ml / kg of Lactobacillus plantarum LP-SG7; the Z2 group was gavaged daily with 0.52 g / kg of the Lactobacillus plantarum LP-SG7 combination; and the Z3 group was gavaged daily with 42 mg / kg of allopurinol. Samples were collected at the end of day 14.

[0114] ③Sample preparation

[0115] After the end of the experiment on the 14th day, blood samples were collected by eyeball bleeding method, centrifuged at 3000 r / min for 15 min, and serum was collected.

[0116] ④Indicator measurement method

[0117] Serum uric acid (UA), serum urea nitrogen (BUN), creatinine (Cr), and xanthine oxidase (XOD) were determined according to the instructions of the uric acid (UA) test kit, urea nitrogen (BUN) test kit, creatinine (Cr) test kit, and xanthine oxidase (XOD) test kit. Each test kit was purchased from Nanjing Jiancheng Bioengineering Institute.

[0118] ⑤Data processing and statistical analysis

[0119] SPSS 21.0 software was used. Data were expressed as mean ± standard deviation (x ± S), and t-test was used for comparison between groups. P < 0.01 was considered extremely significant, and P < 0.05 was considered significant.

[0120] ⑥Experimental results

[0121] (1) Effects of Lactobacillus plantarum LP-SG7 and its postbiotic composition on serum uric acid

[0122] The results are shown in Table 8. It can be seen that both the live Lactobacillus plantarum LP-SG7 bacteria and the composition can reduce serum uric acid, and the effect of the composition in reducing uric acid is more obvious.

[0123] (2) Effects of Lactobacillus plantarum LP-SG7 and its postbiotic composition on serum urea nitrogen

[0124] The results are shown in Table 8. It can be seen that the live bacteria of Lactobacillus plantarum LP-SG7 and the composition have a certain effect of reducing serum uric acid nitrogen, among which the effect of the composition in reducing serum urea nitrogen is more obvious.

[0125] (3) Effects of Lactobacillus plantarum LP-SG7 and its postbiotic composition on creatinine

[0126] The results are shown in Table 8. It can be seen that the live bacteria of Lactobacillus plantarum LP-SG7 and the composition have a certain effect on reducing creatinine, among which the effect of the composition on reducing creatinine is more obvious.

[0127] (4) Effects of Lactobacillus plantarum LP-SG7 and its postbiotic composition on xanthine oxidase

[0128] The results are shown in Table 8. It can be seen that the live bacteria of Lactobacillus plantarum LP-SG7 and the composition have a certain effect of reducing xanthine oxidase, among which the effect of the composition in reducing xanthine oxidase is more obvious.

[0129] Table 8 Effects of Lactobacillus plantarum LP-SG7 on UA, BUN, Cr and XOD levels in hyperuricemia rats

[0130]

[0131]

[0132] Note: *Compared with the model group, **p<0.01, *p<0.05.

[0133] In summary, Lactobacillus plantarum LP-SG7 and its postbiotic composition can reduce the levels of uric acid, urea nitrogen, and creatinine in rat serum and inhibit the activity of xanthine oxidase in liver tissue, thereby alleviating hyperuricemia. This effect is similar to that of allopurinol. This provides a basis for adjuvant treatment of hyperuricemia and offers new ideas for the development of new drugs for the treatment of hyperuricemia and foods or health products that help lower uric acid.

Claims

1. A Lactobacillus plantarum LP-SG7 having uric acid-lowering function, wherein: The classification name of the Lactobacillus plantarum LP-SG7 is Lactobacillus Plantarum, and its preservation number is CGMCC No. 29702.

2. The postbiotic powder prepared by the Lactobacillus plantarum LP-SG7 according to claim 1.

3. The method for preparing the postbiotic powder according to claim 2, comprising the following steps: 1) inoculating the Lactobacillus plantarum LP-SG7 according to claim 1 onto MRS medium for activation; 2) preparing a bacterial suspension or liquid seed of the activated Lactobacillus plantarum LP-SG7 and inoculating it into a fermentation medium at an inoculum size of 5%, and fermenting it at a temperature of 30-40° C. under anaerobic or facultative anaerobic stirring conditions for 10-18 hours to obtain a live bacterial fermentation liquid after fermentation is completed; 3) The live bacteria fermentation liquid is subjected to high temperature inactivation treatment and spray-dried to obtain the postbiotic powder.

4. The preparation method according to claim 3, wherein In step 3), the concentration of live bacteria in the live bacteria fermentation broth is greater than 10 11 cfu / ml; preferably, the concentration of live bacteria in the live bacteria fermentation broth is 10 11 -10 12 cfu / ml.

5. The preparation method according to claim 3, wherein In step 3), the high temperature inactivation treatment is performed at a temperature of 55° C. to 80° C. and for a time of 0.5 h to 3 h.

6. A composition comprising the live bacteria of Lactobacillus plantarum LP-SG7 according to claim 1 and the postbiotic powder according to claim 2.

7. The composition according to claim 6, wherein The mass ratio of the live bacteria of the Lactobacillus plantarum LP-SG7 to the postbiotic powder is 1:1-1:

4.

8. Use of the Lactobacillus plantarum LP-SG7 according to claim 1, the postbiotic powder according to claim 2, or the composition according to claim 6 or 7 in the preparation of a medicament for alleviating hyperuricemia.

9. Use of the Lactobacillus plantarum LP-SG7 according to claim 1, the postbiotic powder according to claim 2, or the composition according to claim 6 or 7 in preparing a food or health product for alleviating hyperuricemia.

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