Lactobacillus plantarum and application thereof

Abstract

The invention belongs to the technical field of microorganisms, and particularly relates to a lactobacillus plantarum (Lactobacillus plantarum) and an application of the lactobacillus plantarum. The preservation number of the lactobacillus plantarum is CGMCC (China General Microbiological Culture Collection Center) NO.24756. The lactobacillus plantarum has good DPPH (1, 1-diphenyl-2-picrylhydrazyl) scavenging capacity, hydroxyl radical scavenging capacity and reducing capacity, and can remarkably reduce the level of malondialdehyde (MDA) as an oxidative stress marker in serum and liver of an oxidative stress body, the pathological damage level of liver tissue and the level of inflammatory factors in serum; the level of an antioxidant substance glutathione (GSH) in serum and liver of an oxidative stress body and the activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in the serum and liver can be remarkably improved. In addition, fire extinguishing bacteria of the lactobacillus plantarum have more excellent antioxidant activity than viable bacteria.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and in particular relates to a Lactobacillus plantarum and an application thereof. Background Art

[0002] Reactive oxygen species such as superoxide anions and hydroxyl radicals are produced during cellular metabolism, and they play an important role in cell signaling, apoptosis, and gene expression. However, when these reactive oxygen molecules are produced excessively or when cellular defenses are insufficient, proteins, fats, and nucleic acid biomolecules may be damaged by oxidative stress. This damage can lead to a variety of diseases, such as cancer, Alzheimer's disease, and Parkinson's disease. In addition to enzymatic and non-enzymatic antioxidant defense and repair systems, various synthetic antioxidants are used to protect the body from oxidative damage; for example, butylated hydroxyanisole (BHT) and butylated hydroxytoluene (BHA), which are widely used in products such as food, health supplements, or cosmetics. However, long-term and high-volume intake of synthetic antioxidants may have negative effects on human health, such as increasing the risk of cancer and cardiovascular disease.

[0003] Therefore, finding natural antioxidants that do not have a negative impact on human health is another safer approach different from synthetic antioxidants. At present, some researchers have found that Lactobacillus plantarum has antioxidant activity and can be used as a natural antioxidant. For example, it was found that Lactobacillus plantarum DP189 increased the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in mice, and reduced the content of oxidative stress marker malondialdehyde (MDA) and the body's inflammation levels including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β); for another example, it was found that Lactobacillus plantarum SCS2 can reduce the serum MDA level of diabetic mice; for another example, it was found that Lactobacillus plantarum KSFY06 has a preventive effect on mice with acute liver injury induced by D-galactose / lipopolysaccharide.

[0004] Therefore, it is of great significance to discover a Lactobacillus plantarum with antioxidant activity. Summary of the invention

[0005] In view of the above problems, one of the purposes of the present invention is to provide a Lactobacillus plantarum CGMCC No. 24756. The Lactobacillus plantarum has good antioxidant activity, and its heat-killed bacteria have stronger antioxidant activity than live bacteria.

[0006] In order to achieve the above object, the present invention can adopt the following technical solutions:

[0007] The present invention provides a Lactobacillus plantarum, whose deposit number is CGMCCNO.24756.

[0008] Another aspect of the present invention provides a heat-killed Lactobacillus plantarum bacterium, which is obtained by heat-killing the above-mentioned Lactobacillus plantarum.

[0009] In another aspect, the present invention provides a culture obtained by culturing the above-mentioned Lactobacillus plantarum.

[0010] In another aspect, the present invention provides an antioxidant composition, which comprises any one of the following substances: (a) the above-mentioned Lactobacillus plantarum; (b) the above-mentioned heat-killed Lactobacillus plantarum; (c) the above-mentioned culture; (d) the above-mentioned culture after heat inactivation.

[0011] In another aspect, the present invention provides an antioxidant preparation, comprising the aforementioned Lactobacillus plantarum or the aforementioned heat-killed bacteria of Lactobacillus plantarum or the aforementioned culture or the aforementioned antioxidant composition; and a carrier.

[0012] In another aspect, the present invention provides a use of the above-mentioned Lactobacillus plantarum or the above-mentioned heat-killed bacteria of Lactobacillus plantarum or the above-mentioned culture or the above-mentioned antioxidant composition in the preparation of antioxidant preparations.

[0013] The Lactobacillus plantarum preservation information of the present invention is as follows: Preservation institution: General Microbiology Center of China Microorganism Culture Collection Administration (CGMCC); Address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing; Preservation date: April 22, 2022; Preservation number: CGMCC No. 24756; Classification name: Lactobacillus plantarum.

[0014] The beneficial effects of the present invention include at least:

[0015] (1) The plant lactobacillus provided by the present invention has good DPPH scavenging ability, hydroxyl free radical scavenging ability and reducing ability, and can significantly reduce the level of malondialdehyde (MDA), a marker of oxidative stress, in the serum and liver of an oxidative stress body; can significantly reduce the level of pathological damage in the liver tissue of an oxidative stress body; can significantly reduce the level of inflammatory factors in the serum of an oxidative stress body; can significantly increase the level of glutathione (GSH), an antioxidant substance, in the serum and liver of an oxidative stress body; and can significantly increase the activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in the serum and liver of an oxidative stress body.

[0016] (2) The heat-killed Lactobacillus plantarum provided by the present invention has stronger DPPH scavenging ability, hydroxyl radical scavenging ability and reducing ability than the live Lactobacillus plantarum of the present invention. The DPPH scavenging ability of the heat-killed Lactobacillus plantarum can reach 41.36%, which is significantly higher than 38.38% of the live bacteria; the hydroxyl radical scavenging ability can reach 90.53%, which is significantly higher than 80.55% of the live bacteria; the reducing ability can reach 231 μmol / L of L-cysteine ​​hydrochloride equivalent, which is significantly higher than 148% of 93 μmol / L of L-cysteine ​​hydrochloride equivalent of the live bacteria; and can significantly reduce the level of pathological damage of liver tissue in oxidative stress bodies; can significantly reduce the level of inflammatory factors in the serum of oxidative stress bodies; can significantly increase the level of antioxidant glutathione (GSH) in the serum and liver of oxidative stress bodies; can significantly increase the activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in the serum and liver of oxidative stress bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a picture of the colony morphology of Lactobacillus plantarum TY-Y10;

[0018] Figure 2 This is the Gram staining result of Lactobacillus plantarum TY-Y10;

[0019] Figure 3 This is a bar graph showing the DPPH scavenging ability of heat-killed Lactobacillus plantarum TY-Y10.

[0020] Figure 4 This is a bar graph showing the hydroxyl radical scavenging ability of heat-killed Lactobacillus plantarum TY-Y10.

[0021] Figure 5 This is a bar graph showing the reducing ability of heat-killed Lactobacillus plantarum TY-Y10 cells;

[0022] Figure 6 It is a bar graph of the level of MDA, a biomarker of oxidative stress in mouse serum;

[0023] Figure 7 This is a bar graph of the level of MDA, a biomarker of oxidative stress in mouse liver;

[0024] Figure 8 This is a bar graph of the level of GSH, an antioxidant substance in mouse serum;

[0025] Fig. 9 This is a bar graph of the level of antioxidant substance GSH in mouse liver;

[0026] Fig.10 This is a bar graph of the activity of the serum antioxidant enzyme SOD in mice;

[0027] Fig.11 This is a bar graph of the activity of the antioxidant enzyme SOD in mouse liver;

[0028] Fig.12 This is a bar graph of the activity of the serum antioxidant enzyme CAT in mice;

[0029] Fig.13 This is a bar graph of the activity of the antioxidant enzyme CAT in mouse liver;

[0030] Fig.14 This is a bar graph of the activity of the serum antioxidant enzyme GPx in mice;

[0031] Fig.15 This is a bar graph of the activity of the antioxidant enzyme GPx in mouse liver;

[0032] Fig.16 This is a histopathological section of mouse liver;

[0033] Fig.17 It is a bar graph of the level of interleukin-6 (IL-6), an inflammatory factor in mouse serum;

[0034] Fig.18 This is a bar graph of the level of the inflammatory factor tumor necrosis factor (TNF-α) in mouse serum;

[0035] Fig.19 It is a bar graph of the level of interferon-γ (IFN-γ), an inflammatory factor in mouse serum;

[0036] in, Figures 6 to 15 , Figures 17 to 19 In, Control: blank control group, D-gal: model group, SA: positive control group, LH: TY-Y10 live bacteria high-dose group, LL: TY-Y10 live bacteria low-dose group, DH: TY-Y10 heat-killed bacteria high-dose group, DL: TY-Y10 heat-killed bacteria low-dose group;

[0037] Fig.16 A: blank group, B: model group, C: positive control group, D: TY-Y10 live bacteria high-dose group, E: TY-Y10 live bacteria low-dose group, F: TY-Y10 heat-killed bacteria high-dose group, G: TY-Y10 heat-killed bacteria low-dose group. DETAILED DESCRIPTION

[0038] The examples are provided to better illustrate the present invention, but the present invention is not limited to the examples. Therefore, those skilled in the art may make non-essential improvements and adjustments to the implementation scheme according to the above invention content, which still fall within the protection scope of the present invention.

[0039] The terms used herein are only used to describe specific embodiments and are not intended to limit the present disclosure. Unless the context has a significantly different meaning, expressions in the singular include expressions in the plural. As used herein, it should be understood that terms such as "include", "have", "include" are intended to indicate the presence of features, numbers, operations, materials, or combinations. The terms of the present invention are disclosed in the specification, and are not intended to exclude the possibility that one or more other features, numbers, operations, materials, or combinations thereof may exist or may be added. As used herein, " / " may be interpreted as "and" or "or", depending on the circumstances.

[0040] An embodiment of the present invention provides a Lactobacillus plantarum, whose deposit number is CGMCCNO.24756.

[0041] It should be noted that the 16SrDNA sequence of the above-mentioned Lactobacillus plantarum is the sequence shown in SEQ ID NO.1, and the specific sequence is as follows:

[0042] GAGGGGGGGGTGCTATACATGCAGTCGAACGAACTCTGGTATTGATTGGTGCTTGCATCA

[0043] TGATTTACATTTGAGTGAGTGGCGAACTGGTGAGTAACACGTGGGAAACCTGCCCAGAA

[0044] GCGGGGGATAACACCTGGAAACAGATGCTAATACCGCATAACAACTTGGACCGCATGGT

[0045] CCGAGCTTGAAAGATGGCTTCGGCTATCACTTTTGGATGGTCCCGCGGCGTATTAGCTAG

[0046] ATGGTGGGGTAACGGCTCACCATGGCAATGATACGTAGCCGACCTGAGAGGGTAATCGG

[0047] CCACATTGGGACTGAGACACGGCCCAAACTCCTACGGGAGGCAGCAGTAGGGAATCTT

[0048] CCACAATGGACGAAAGTCTGATGGAGCAACGCCGCGTGAGTGAAGAAGGGTTTCGGCT

[0049] CGTAAAACTCTGTTGTTAAAGAAGAACATATCTGAGAGTAACTGTTCAGGTATTGACGGT

[0050] ATTTAACCAGAAAGCCACGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGTGGC

[0051] AAGCGTTGTCCGGATTTATTGGGCGTAAAGCGAGCGCAGGCGGTTTTTTAAGTCTGATGT

[0052] GAAAGCCTTCGGCTCAACCGAAGAAGTGCATCGGAAACTGGGAAACTTGAGTGCAGAA

[0053] GAGGACAGTGGAACTCCATGTGTAGCGGTGAAATGCGTAGATATATGGAAGAACACCAG

[0054] TGGCGAAGGCGGCTGTCTGGTCTGTAACTGACGCTGAGGCTCGAAAGTATGGGTAGCA

[0055] AACAGGATTAGATACCCTGGTAGTCCATACCGTAAACGATGAATGCTAAGTGTTGGAGG

[0056] GTTTCCGCCCTTCAGTGCTGCAGCTAACGCATTAAGCATTCCGCCTGGGGAGTACGGCC

[0057] GCAAGGCTGAAACTCAAAGGAATTGACGGGGGCCCGCACAAGCGGTGGAGCATGTGGT

[0058] TTAATTCGAAGCTACGCGAAGAACCTTACCAGGTCTTGACATACTATGCAAATCTAAGAG

[0059] ATTAGACGTTCCCTTCGGGGACATGGATACAGGTGGTGCATGGTTGTCGTCAGCTCGTGT

[0060] CGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTATTATCAGTTGCCAGCATT

[0061] AAGTTGGGCACTCTGGTGAGACTGCCGGTGACAAACCGGAGGAAGGTGGGGATGACGT

[0062] CAAATCATCATGCCCCTTATGACCTGGGCTACACACGTGCTACAATGGATGGTACAACGA

[0063] GTTGCGAACTCGCGAGAGTAAGCTAATCTCTTAAAGCCATTCTCAGTTCGGATTGTAGGC

[0064] TGCAACTCGCCTACATGAAGTCGGAATCGCTAGTAATCGCGGATCAGCATGCCGCGGTG

[0065] AATACGTTCCCGGGCCTTGTACACACCGCCCGTCACACCATGAGAGTTTGTAACACCCAAAGTCGGTGGGGTAACCTTTTAGGAACCAGCCTGCCTAAGTGACAC.

[0066] In addition, the above-mentioned plant lactobacillus has a significant antioxidant effect, has good DPPH scavenging ability, hydroxyl free radical scavenging ability and reducing ability, and can significantly reduce the level of oxidative stress marker malondialdehyde (MDA) in the serum and liver of oxidative stress bodies; can significantly reduce the level of pathological damage in liver tissue of oxidative stress bodies; can significantly reduce the level of inflammatory factors in the serum of oxidative stress bodies; can significantly increase the level of antioxidant glutathione (GSH) in the serum and liver of oxidative stress bodies; can significantly increase the activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in the serum and liver of oxidative stress bodies.

[0067] Another embodiment of the present invention provides a heat-killed Lactobacillus plantarum bacterium, which is obtained by heat-killing the above-mentioned Lactobacillus plantarum. It should be noted that the present invention finds that the antioxidant capacity of the heat-inactivated strain of the above-mentioned plant lactobacillus after heat inactivation treatment is stronger than that of the above-mentioned plant lactobacillus live bacteria; for example, the DPPH scavenging capacity of the heat-inactivated strain can reach 41.36%, which is significantly higher than 38.38% of the live bacteria; the hydroxyl free radical scavenging capacity of the heat-inactivated strain can reach 90.53%, which is significantly higher than 80.55% of the live bacteria; the reducing capacity of the heat-inactivated strain can reach 231 μmol / L of L-cysteine ​​hydrochloride equivalent, which is significantly higher than 148% of 93 μmol / L of L-cysteine ​​hydrochloride equivalent of the live bacteria; and it can significantly reduce the level of pathological damage of liver tissue in oxidative stress bodies; it can significantly reduce the level of inflammatory factors in the serum of oxidative stress bodies; it can significantly increase the level of antioxidant glutathione (GSH) in the serum and liver of oxidative stress bodies; it can significantly increase the activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in the serum and liver of oxidative stress bodies.

[0068] In some specific embodiments, the above-mentioned method for heat inactivation of Lactobacillus plantarum may include: inoculating Lactobacillus plantarum in a culture medium, culturing at 30°C to 37°C for 8h-12h, continuously subculturing twice, centrifuging to obtain bacterial sludge, and inactivating the bacterial sludge with high-pressure steam at 80°C to 100°C to obtain heat-inactivated Lactobacillus plantarum bacteria.

[0069] It should be noted that the method for heat inactivation of plant lactobacillus can be a method known in the art, preferably the above method; wherein the temperature of high pressure steam inactivation can be 85°C, 90°C or 95°C, etc., preferably 80°C, and the strains inactivated at 80°C have stronger antioxidant capacity than the strains inactivated at other temperatures. In addition, the culture temperature can be 32°C, 35°C or 36°C, etc., generally 35°C is selected, which is a problem that the strain is suitable for growth, and the culture time can be determined according to the specific situation, generally 12h is enough.

[0070] It should also be noted that live Lactobacillus plantarum is greatly affected by the environment, requires cold chain transportation and special protection, and must ensure that a certain number of live bacteria reach the intestines to exert beneficial effects, which limits its commercial development. Inactivated bacteria are safer, more stable, not controlled by the number of live bacteria, and not affected by environmental factors such as production, transportation and storage, and have a very broad application prospect.

[0071] Another embodiment of the present invention provides a culture obtained by culturing the above-mentioned Lactobacillus plantarum. It should be noted that the culture obtained by culturing the above-mentioned Lactobacillus plantarum also has antioxidant capacity, and the culture is generally a fermentation liquid or a metabolite.

[0072] Another embodiment of the present invention provides an antioxidant composition, which includes any one of the following substances: (a) the above-mentioned Lactobacillus plantarum; (b) the above-mentioned heat-killed Lactobacillus plantarum; (c) the above-mentioned culture; (d) the above-mentioned culture after heat inactivation.

[0073] It should be noted that the above-mentioned plant lactobacillus, heat-killed bacteria, heat-killed culture and plant lactobacillus can be added with other active substances and used in combination to achieve a synergistic effect. Other active substances can be dietary fibers that are conducive to bacterial growth, can be other probiotics, or can be compounds with antioxidant activity, and specific selection can be selected according to specific circumstances.

[0074] Another embodiment of the present invention provides an antioxidant preparation, comprising the aforementioned Lactobacillus plantarum or the aforementioned heat-killed bacteria of Lactobacillus plantarum or the aforementioned culture or the aforementioned antioxidant composition; and a carrier.

[0075] It should be noted that the above-mentioned Lactobacillus plantarum, heat-killed bacteria, Lactobacillus plantarum culture and antioxidant composition can be added with a carrier to prepare various preparations.

[0076] In some specific embodiments, the above-mentioned preparations include food, nutritional supplements, health products, cosmetics or medicines. It should be noted that suitable carriers can be added to prepare the above-mentioned preparations into the form of food, nutritional supplements, health products, cosmetics or medicines, and the specific type can be selected according to the specific situation. The carriers are all known in the art.

[0077] In some specific embodiments, food, nutritional supplements, health products or medicines can be in different dosage forms, such as tablets, pills, capsules, powders, pastes, gels, granules or liquids. It should be understood that the selected carriers will be different according to the dosage forms of different preparations. For example, the preparation of tablets mainly uses diluents (such as starch, dextrin, sucrose or glycosides), absorbents (calcium sulfate, calcium hydrogen phosphate or light magnesium oxide, etc.), binders (povidone, syrup or hydroxypropyl methylcellulose), wetting agents (water, etc.) or disintegrants (dry starch, sodium hydroxymethyl starch or cross-linked polyvinylpyrrolidone, etc.); for example, the preparation of liquids mainly uses expanders, suspending agents, emulsifiers or colorants. In some specific embodiments, the above-mentioned preparations can be biscuits, powders or milk tablets; in other specific embodiments, the preparations can be stirred yogurt or probiotic beverages; in other specific embodiments, the preparations can be jelly, milk caps or solidified yogurt; in other specific embodiments, the preparations can be tablets or capsules.

[0078] Another aspect of the present invention provides an application of the above-mentioned Lactobacillus plantarum or the above-mentioned heat-killed Lactobacillus plantarum bacteria or the above-mentioned culture or the above-mentioned antioxidant composition in the preparation of antioxidant preparations. It should be noted that, as mentioned above, the above-mentioned Lactobacillus plantarum or the above-mentioned heat-killed Lactobacillus plantarum bacteria or the above-mentioned culture or the above-mentioned antioxidant composition all have antioxidant activity and can be used in the preparation and application of antioxidant preparations.

[0079] In some specific embodiments, the above-mentioned applications may include one or more of the following: (a) application in the preparation of a preparation for scavenging DPPH; (b) application in the preparation of a preparation for scavenging hydroxyl radicals; (c) application in the preparation of a preparation with reducing ability; (d) application in the preparation of a preparation for reducing the level of malondialdehyde in serum and liver after oxidative stress of the body; (e) application in the preparation of a preparation for reducing the level of pathological damage in liver tissue after oxidative stress of the body; (f) application in the preparation of a preparation for reducing the level of inflammatory factors in serum after oxidative stress of the body; (g) application in the preparation of a preparation for increasing the level of glutathione in serum and liver after oxidative stress of the body; (h) application in the preparation of a preparation for increasing the activity of superoxide dismutase, catalase and glutathione peroxidase in serum and liver after oxidative stress of the body.

[0080] It should be noted that the above-mentioned Lactobacillus plantarum or the above-mentioned heat-killed bacteria of Lactobacillus plantarum or the above-mentioned culture or the above-mentioned antioxidant composition exerts its antioxidant activity through one or more combinations of the above-mentioned (a) to (h).

[0081] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with specific examples, but the content of the present invention is not limited to the following examples.

[0082] In the following examples, Lactobacillus plantarum CGMCC NO.24756 is also referred to as TY-Y10 or Lactobacillus plantarum TY-Y10.

[0083] In the following examples, MRS culture medium was obtained from Beijing Luqiao Technology Co., Ltd.

[0084] 1. Isolation, purification and identification of TY-Y10

[0085] (1) Experimental Materials

[0086] The kimchi samples collected from the homemade kimchi of families in Weishan, Dali were stored at 4°C. 25 g of the collected fermented solid samples were weighed with sterile tweezers on a sterile operating table and homogenized in a sterile sampling bag containing 225 mL of 0.85% saline for 30 minutes to make the samples uniform.

[0087] (2) Isolation and purification of TY-Y10

[0088] Under sterile conditions, pipette 1 mL of the sample in (1) into 9 mL of sterile saline and vortex to mix. -1 The sample diluent was then diluted 10-fold to 10 -7 , select 10 -5 , 10 -6 and 10 -7 100 μL of the dilution solution at the dilution degree was evenly spread on the MRS plate and inverted for incubation at 37°C for 48 hours. After the incubation, the morphology of the colonies on the MRS plate was observed, and medium-sized, raised, slightly white or slightly yellow, moist, with neat edges and round shapes of colonies were selected for plate streak method to purify the strains. The streak operation was repeated until the purified strains were obtained.

[0089] (3) Morphological and structural observation

[0090] The purified strain in (2) was inoculated into 9 mL of sterile MRS medium and cultured at 37°C for 12 h; 1 mL of bacterial solution was centrifuged at 12000 r / min for 1 min, then washed twice with sterile saline, and then an equal volume of sterile saline was added to resuspend the bacteria. Finally, a small amount was evenly spread on a glass slide using an inoculation loop, fixed, and Gram-stained, microscopically examined, and photographed; Gram-positive bacteria (G+) cells were blue-purple after staining, and Gram-negative bacteria (G) cells were red; the colony morphology of the strain and the Gram-staining results were observed and recorded;

[0091] The colony morphology of the strains Figure 1 As shown in the figure, after the strain was purified, a single colony was formed in the solid culture medium. The colony morphology was consistent, hemispherical, white, smooth and moist on the surface, and with a flat edge. The Gram staining results were as follows Figure 2 As shown, purple cells were observed under a microscope after Gram staining ( Figure 2 Grayscale processing was done, the original image was purple), the shape was rod-shaped, and it was determined to be Gram-positive bacteria (G).

[0092] (3) 16S rDNA sequencing

[0093] The purified bacterial solution in (2) was subjected to PCR amplification to obtain a PCR amplification product, specifically comprising: a 25 μL PCR reaction system: 1 μL template; 12.5 μL 2×Taq PCR Master Mix; 1 μL each of bacterial universal primers (27F, 1492R); sterile ultrapure water to 25 μL; reaction conditions: 94°C pre-denaturation for 5 min; 94°C denaturation for 30 s; 55°C annealing for 30 s; 72°C extension for 1 min, for a total of 30 cycles; 72°C terminal extension for 10 min; after the reaction, a PCR amplification product was obtained; the PCR amplification product was sent to Shanghai Biotech Co., Ltd. for sequencing, and the sequence was as shown in SEQ ID No. 1; BLAST (http: / / www.ncbi.nlm.nih.gov / BLAST) was used to search and homology analysis in GenBank, and the homology analysis results showed that TY-Y10 was Lactobacillus plantarum.

[0094] 2. Bacterial Culture

[0095] (1) TY-Y10 live bacterial cell culture

[0096] The Lactobacillus plantarum TY-Y10 stored at -80°C was dissolved, inoculated into MRS liquid medium at a 2% inoculum, cultured for 12 h, inoculated into MRS solid medium for 48 h, inoculated into MRS liquid medium for 12 h, and then inoculated into MRS liquid medium at a 2% inoculum for 12 h. The supernatant was removed by centrifugation (4500 rpm, 10 min), the bacteria were washed twice with PBS, and then resuspended with 0.9% saline to adjust the bacterial suspension concentration to 1×10 9 CFU / mL.

[0097] Preparation of live supernatant of Lactobacillus plantarum TY-Y10 for in vitro experiments: Take Lactobacillus plantarum TY-Y10 after two generations of activation, inoculate it in MRS liquid culture medium at an inoculum size of 2%, culture it for 12 hours, centrifuge (4500rpm, 10min) to collect the supernatant, and then filter it with a 0.22μm sterile filter membrane to obtain the fermentation supernatant of Lactobacillus plantarum TY-Y10.

[0098] Live Lactobacillus plantarum TY-Y10 cells used for animal experiments: TY-Y10 cells were subcultured twice and then inoculated into MRS liquid culture medium for 12 hours, with an inoculation volume of 2% (v / v) each time; the cells were centrifuged at 4500 rpm for 10 minutes, the supernatant was discarded, the cells after centrifugation were collected, washed twice with sterile ultrapure water, resuspended, and centrifuged; the cells were resuspended with 12% skim milk, freeze-dried, and the weight of the freeze-dried powder and the amount of live bacteria were determined to obtain live Lactobacillus plantarum TY-Y10 powder (i.e., complete Lactobacillus plantarum TY-Y10 cells); when administered intragastricly, the cells were resuspended with physiological saline.

[0099] (2) TY-Y10 heat-killed bacterial cell culture

[0100] After Lactobacillus plantarum was activated for two generations in MRS medium, it was inoculated in MRS liquid medium at a 2% inoculum and cultured for 12 hours. It was inactivated by high-pressure steam at 80 and 100°C for 20 minutes, centrifuged (4500 rpm, 10 minutes) to remove the supernatant, washed twice with PBS, and resuspended in 0.9% saline.

[0101] Heat-inactivated supernatant of Lactobacillus plantarum TY-Y10 used for in vitro test: Take Lactobacillus plantarum after two generations of activation, inoculate it in MRS liquid culture medium at an inoculum size of 2%, and culture it for 12 hours, then inactivate it with high-pressure steam at 80°C and 100°C for 20 minutes, respectively, collect the supernatant by centrifugation (4500rpm, 10min), and then filter it with a 0.22μm sterile filter membrane to obtain 80°C heat-inactivated Lactobacillus plantarum TY-Y10 fermentation supernatant and 100°C heat-inactivated Lactobacillus plantarum TY-Y10 fermentation supernatant.

[0102] Heat-inactivated Lactobacillus plantarum TY-Y10 bacteria for animal experiments: The above-mentioned live bacteria powder of Lactobacillus plantarum TY-Y10 was inactivated at 80°C and 100°C for 20 minutes respectively to obtain heat-inactivated live bacteria powder (i.e., 80°C heat-inactivated Lactobacillus plantarum TY-Y10 complete bacteria and 100°C heat-inactivated Lactobacillus plantarum TY-Y10 complete bacteria). When gavage, resuspend with physiological saline.

[0103] (3) Live bacterial culture of L. rhamnosus GG (LGG)

[0104] The LGG cells were cultured according to the live cell culture method of Lactobacillus plantarum TY-Y10 to obtain LGG fermentation supernatant and LGG complete cells, respectively.

[0105] (4) Culture of heat-killed L. rhamnosus GG (LGG) bacteria

[0106] According to the above-mentioned heat-killed bacterial cell culture method of Lactobacillus plantarum TY-Y10, LGG (Lactobacillus rhamnosus) cells were cultured to obtain 80°C heat-killed Lactobacillus plantarum LGG fermentation supernatant and 100°C heat-killed Lactobacillus plantarum LGG fermentation supernatant, 80°C heat-killed Lactobacillus plantarum LGG complete cells and 100°C heat-killed Lactobacillus plantarum LGG complete cells. III. In vitro test of TY-Y10 antioxidant activity

[0107] (1) DPPH scavenging ability determination

[0108] Prepare samples: add 1 ml of the above-mentioned cultured Lactobacillus plantarum TY-Y10 fermentation supernatant, Lactobacillus plantarum TY-Y10 complete bacteria, LGG fermentation supernatant, LGG complete bacteria, 80°C heat-killed Lactobacillus plantarum TY-Y10 fermentation supernatant, 80°C heat-killed Lactobacillus plantarum TY-Y10 complete bacteria, 80°C heat-killed Lactobacillus plantarum LGG fermentation supernatant, and 80°C heat-killed Lactobacillus plantarum LGG complete bacteria, 100°C heat-killed Lactobacillus plantarum TY-Y10 fermentation supernatant, 100°C heat-killed Lactobacillus plantarum TY-Y10 complete bacteria, 100°C heat-killed Lactobacillus plantarum LGG fermentation supernatant and 100°C heat-killed Lactobacillus plantarum LGG complete bacteria to 1 mL of the freshly prepared DPPH (2,2-diphenyl-1-picrylhydrazyl) anhydrous ethanol solution, and mix thoroughly;

[0109] Reaction in dark place: The mixed sample is reacted in dark place at 37℃ for 30min. The DPPH free radicals will react with the antioxidant components in the substance to be tested, and the purple color will be lost, thus determining the antioxidant capacity.

[0110] Centrifugation: After the reaction is completed, centrifuge at 4500 rpm for 10 min and take out the supernatant;

[0111] Determine absorbance: Determine the absorbance of samples and controls (As517 and Ac517) at a wavelength of 517 nm;

[0112] Calculation of DPPH scavenging ability: Calculate the percentage inhibition rate of DPPH scavenging ability (AA) according to the following formula: DPPH free radical scavenging rate (%) = [1-As517 / Ac517] × 100%, where As517 is the absorbance value of the sample group; Ac517 is the absorbance value of the control group.

[0113] The DPPH scavenging ability of each group of strains is shown in Table 1 and Figure 3 As shown, the DPPH scavenging rate of the intact bacteria of Lactobacillus plantarum TY-Y10 heat-killed at 80°C was the highest, reaching (41.37±0.81)%> the intact bacteria of TY-Y10 without heat inactivation (35.40±0.94)%> the intact bacteria of Lactobacillus plantarum TY-Y10 heat-killed at 100°C (32.41±0.81)%; in addition, the DPPH scavenging rate of the fermentation supernatant of Lactobacillus plantarum TY-Y10 decreased after heat inactivation; in addition, the DPPH free radical scavenging ability of the fermentation supernatant and intact bacteria of the LGG strain after heat inactivation was significantly reduced.

[0114] Table 1 DPPH scavenging ability of each group of strains

[0115]

[0116] Note:abc Indicates that the comparison within the same column is significant (p<0.05); * indicates that the comparison with the control is significant (*p<0.05, **p<0.01, ***p<0.001).

[0117] (2) Determination of hydroxyl radical scavenging ability

[0118] 1 mL of the above-cultured Lactobacillus plantarum TY-Y10 fermentation supernatant, Lactobacillus plantarum TY-Y10 whole cells, LGG fermentation supernatant, LGG whole cells, 80°C heat-killed Lactobacillus plantarum TY-Y10 fermentation supernatant, 80°C heat-killed Lactobacillus plantarum TY-Y10 whole cells, 80°C heat-killed LGG fermentation supernatant, 80°C heat-killed LGG whole cells, 100°C heat-killed Lactobacillus plantarum TY-Y10 fermentation supernatant, 100°C heat-killed Lactobacillus plantarum TY-Y10 whole cells, 100°C heat-killed LGG fermentation supernatant and 100°C heat-killed LGG whole cells were respectively mixed with 1 mL of 1,10-phenanthroline, 1 mL of PBS phosphate buffer and 1 mL of freshly prepared FeSO2 solution to obtain a mixed system; and then 1 mL of 20mmol / L H2O2, water bath at 37℃ for 90min; the sample absorbance was measured at 536nm wavelength, expressed as As536;

[0119] The sample in the mixed system was replaced with the same volume of MRS liquid culture medium, and the absorbance was measured at a wavelength of 536 nm, expressed as Ab536;

[0120] Replace H2O2 in the mixed system with an equal volume of pure water, and measure the absorbance at a wavelength of 536nm, expressed as Ac536;

[0121] The calculation was performed according to the following formula: hydroxyl radical scavenging rate (%) = [As536-Ab536] / [Ac536-Ab536]×100%, wherein As536 is the absorbance value of the sample group; Ac536 is the absorbance value of the control group; and Ab536 is the absorbance value of the blank group.

[0122] The hydroxyl radical scavenging ability of each group of strains is shown in Table 2 and Figure 4As shown, the hydroxyl radical scavenging rate of the intact bacteria of Lactobacillus plantarum TY-Y10 heat-killed at 80°C was the highest, reaching (90.53±2.54)%>the intact bacteria of TY-Y10 without heat inactivation (80.55±1.62)%>the intact bacteria of Lactobacillus plantarum TY-Y10 heat-killed at 100°C (76.8±0.71)%; in addition, the hydroxyl radical scavenging rate of the fermentation supernatant of Lactobacillus plantarum TY-Y10 after heat inactivation was improved, the fermentation supernatant of Lactobacillus plantarum TY-Y10 heat-killed at 100°C>the fermentation supernatant of Lactobacillus plantarum TY-Y10 heat-killed at 80°C>the fermentation supernatant of Lactobacillus plantarum TY-Y10 without heat inactivation; in addition, the hydroxyl radical scavenging rate of the intact bacteria of the LGG strain after heat inactivation was significantly reduced.

[0123] Table 2 Hydroxyl radical scavenging ability of each group of strains

[0124]

[0125]

[0126] Note: abc Indicates that the comparison within the same column is significant (p<0.05); * indicates that the comparison with the control is significant (*p<0.05, **p<0.01, ***p<0.001).

[0127] (3) Determination of reducing ability

[0128] L-cysteine ​​hydrochloride was used as a standard for characterizing reducing power as follows:

[0129] Preparation of standard curve: prepare L-cysteine ​​hydrochloride solutions with different gradient concentrations of 20 μmol / L, 40 μmol / L, 60 μmol / L, 80 μmol / L, 100 μmol / L, 120 μmol / L, 140 μmol / L, 160 μmol / L, 180 μmol / L and 200 μmol / L, and prepare the standard curve with the concentration of L-cysteine ​​hydrochloride as the abscissa and the absorbance value as the ordinate;

[0130] Measurement samples: 0.5 mL of the above-cultured Lactobacillus plantarum TY-Y10 fermentation supernatant, Lactobacillus plantarum TY-Y10 whole bacteria, LGG fermentation supernatant, LGG whole bacteria, 80°C heat-killed Lactobacillus plantarum TY-Y10 fermentation supernatant, 80°C heat-killed Lactobacillus plantarum TY-Y10 whole bacteria, 80°C heat-killed LGG fermentation supernatant, 80°C heat-killed LGG whole bacteria, 100°C heat-killed Lactobacillus plantarum TY-Y10 fermentation supernatant, 100°C heat-killed Lactobacillus plantarum TY-Y10 whole bacteria, 100°C heat-killed LGG fermentation supernatant were vortexed. The supernatant and the complete LGG cells heat-killed at 100°C were mixed with 0.5 mL 1% potassium ferrocyanide and 0.5 mL PBS phosphate buffer, respectively, to ensure that the system was evenly mixed; the sample was replaced with the same volume of MRS liquid culture medium, and mixed with potassium ferrocyanide and PBS phosphate buffer solution as a blank control; after reacting in a water bath at 50°C for 20 minutes, it was quickly cooled with an ice-water mixture, 0.5 mL 10% trichloroacetic acid was added, and centrifuged at 4500 rpm for 10 minutes. 1 mL of the supernatant was mixed with 1 mL 0.1% ferric chloride solution and allowed to stand for 10 minutes, and the absorbance was measured at a wavelength of 700 nm.

[0131] The reducing ability of each group of strains is shown in Table 3 and Figure 5 As shown, the reducing ability of the whole bacteria of Lactobacillus plantarum TY-Y10 heat-killed at 80°C was the strongest, reaching (230.94±6.57)%>the whole bacteria of TY-Y10 without heat inactivation (169.28±5.12)%>the whole bacteria of Lactobacillus plantarum TY-Y10 heat-killed at 100°C (93.05±1.46)%; in addition, the reducing ability of the fermentation supernatant of Lactobacillus plantarum TY-Y10 after heat inactivation at 80°C was improved, the fermentation supernatant of Lactobacillus plantarum TY-Y10 heat-killed at 80°C>the fermentation supernatant of Lactobacillus plantarum TY-Y10 without heat inactivation>the fermentation supernatant of Lactobacillus plantarum TY-Y10 heat-killed at 100°C.

[0132] Table 3 Reducing ability of each group of strains

[0133]

[0134]

[0135] Note: abc Indicates that the comparison within the same column is significant (p<0.05); * indicates that the comparison with the control is significant (*p<0.05, **p<0.01, ***p<0.001).

[0136] IV. Animal test of TY-Y10 antioxidant activity

[0137] In the embodiments of the present invention, the selection and treatment of animals in animal experiments are carried out according to the following methods:

[0138] The experimental animals were SPF-grade 6-week-old male BALB / c mice, strain code: T002726, weighing 17g-22g; they were raised in a standard animal laboratory with SPF-grade cleanliness, 12h light alternation, room temperature of 22±1°C, humidity of 50%; the mice moved freely and ate independently; after one week of adaptation, 84 mice were randomly divided into 7 groups, 12 mice in each group; the 7 groups were blank control group, model group, positive control group, TY-Y10 live bacteria high-dose group, TY-Y10 live bacteria low-dose group, TY-Y10 heat-killed bacteria high-dose group and TY-Y10 heat-killed bacteria low-dose group; the dosing conditions of each group are shown in Table 4 below.

[0139] Table 4 Drug administration in different groups of the experiment

[0140]

[0141] At the end of the experiment, the mice were fasted overnight but not water for 12 hours, and their eyeballs were removed while alive and blood was collected into sterile blood collection tubes; the collected blood was allowed to stand at room temperature for 2 hours, centrifuged at 40°C and 4000g for 15 minutes to prepare serum; and stored at -80°C until testing.

[0142] In addition, after blood was collected from the mice, the abdominal cavity was opened and the liver was separated; the liver tissue was washed with sterile PBS to remove surface moisture; the left lateral lobe of the liver was cut and fixed with 4% paraformaldehyde for pathological examination, and the rest was wrapped in tin foil and frozen at -80°C for testing.

[0143] (1) Determination of serum and liver antioxidant indexes

[0144] Nanjing Jiancheng kits were used to measure serum and liver antioxidant indexes, including malondialdehyde (MDA) content, glutathione (GSH) content, superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity, and catalase (CAT) activity.

[0145] Malondialdehyde (MDA) content in serum and liver of mice Figure 6 and Figure 7As shown, the MDA content of mice in the model group was significantly higher (p<0.05) than that in the blank control group; the serum MDA content of mice in the positive control group (SA) was significantly lower than that in the model group, and there was no significant difference with the blank control group; the serum MDA content of mice in the four TY-Y10 intervention groups was significantly lower than that in the model group; among them, the serum MDA content of mice in the high-dose heat-killed bacteria group was the lowest. The results showed that D-galactose (D-gal) induced oxidative stress in mice, and the serum MDA content of mice increased. The intervention of high- and low-dose live bacteria and heat-killed bacteria of TY-Y10 could reduce the serum MDA content of mice and the level of oxidative damage in mice, and its effect was similar to that of sodium ascorbate, among which the high-dose heat-killed bacteria intervention had the best effect.

[0146] Serum and liver glutathione (GSH) levels in mice Figure 8 and Fig. 9 As shown, the serum GSH content of mice in the model group was significantly lower (p<0.05) than that in the blank control group; the serum GSH content of mice in the positive control group was significantly higher than that in the model group; the serum MDA content of mice in the four TY-Y10 intervention groups was significantly higher than that in the model group (p<0.05). The results showed that D-galactose induced oxidative stress in mice, and the serum GSH content of mice decreased. High and low doses of live bacteria and heat-killed bacteria intervention with TY-Y10 could increase the serum GSH content of mice and reduce the level of oxidative damage in mice. Its effect was similar to that of sodium ascorbate, among which the high-dose live bacteria group and the high-dose heat-killed bacteria intervention had the best effect.

[0147] Superoxide dismutase (SOD) activity in serum and liver of mice Fig.10 and Fig.11 As shown, the serum SOD activity of mice in the model group was significantly lower (p<0.05) than that in the blank control group; the serum SOD activity of mice in the positive control group was significantly higher than that in the model group; the serum SOD activity of mice in the four TY-Y10 intervention groups was significantly higher than that in the model group (p<0.05). Among them, the serum SOD activity of mice in the high and low dose groups of heat-killed bacteria was significantly higher than that in the positive control group, and the serum SOD activity of mice in the high and low dose groups of heat-killed bacteria was the highest. The results showed that D-galactose induced oxidative stress in mice, and the serum SOD activity of mice decreased. Sodium ascorbate and high and low doses of TY-Y10 live bacteria and heat-killed bacteria interventions could increase the serum SOD activity of mice and reduce the level of oxidative damage in mice, among which the high dose of heat-killed bacteria intervention had the best effect.

[0148] Catalase (CAT) activity in serum and liver of mice Fig.12 and Fig.13As shown, the serum CAT activity of mice in the model group was significantly lower (p<0.05) than that in the blank control group; the serum CAT activity of mice in the positive control group was significantly higher than that in the model group, and significantly higher than that in the blank control group; the serum CAT activity of mice in the four TY-Y10 intervention groups was significantly higher than that in the blank control group (p<0.05). Among them, the serum CAT activity of mice in the high-dose live bacteria group and the high-dose heat-killed bacteria group was the highest, significantly higher than that in the positive control group (p<0.05). The results showed that D-galactose induced oxidative stress in mice, and the serum CAT activity of mice decreased. Sodium ascorbate and high and low doses of live bacteria and heat-killed bacteria interventions of TY-Y10 could increase the serum CAT activity of mice and reduce the level of oxidative damage in mice. Among them, the high-dose live bacteria group and the high-dose heat-killed bacteria intervention had the best effect.

[0149] Glutathione peroxidase (GPx) activity in serum and liver of mice Fig.14 and Fig.15 As shown in the figure, the activity of serum GPx in the model group was significantly lower than that in the blank control group (p<0.05); the activity of serum GPx in the positive control group was significantly higher than that in the model group, and there was no significant difference with the blank control group; the activity of serum GPx in the four TY-Y10 intervention groups was significantly higher than that in the model group (p<0.05). Among them, the activity of serum GPx in the high-dose heat-killed bacteria group was the highest, significantly higher than that in the positive control group (p<0.05). The results showed that D-galactose induced oxidative stress in mice, and the activity of serum GPx in mice decreased. Sodium ascorbate and high and low doses of TY-Y10 live bacteria and heat-killed bacteria intervention could increase the activity of serum GPx in mice and reduce the level of oxidative damage in mice, among which the high-dose heat-killed bacteria intervention had the best effect.

[0150] (2) HE staining of liver tissue

[0151] Rinse: Take the tissue sample out of the fixative, rinse it gently, and remove the excess fixative; Dehydration: Dehydrate the tissue in 75% ethanol for 3 hours, then dehydrate in 85% ethanol for 1 hour, 95% ethanol for 80 minutes, and 100% ethanol for three times, each time for 25 minutes, 20 minutes, and 20 minutes, respectively, to allow the tissue to penetrate into the ethanol;

[0152] Cleaning: Soak in a solution of 100% ethanol and xylene in a ratio of 1:1 for 20 minutes, and then soak in xylene twice, each time for 15 minutes;

[0153] Embedding: Paraffin treatment three times, each time for 1h, 2h and 3h; Sectioning: The embedded tissue samples were cut into very thin sections with a microtome and the slices were transferred to glass slides;

[0154] Dewaxing: Wash twice with xylene, each time for 10 min;

[0155] Dehydration again: wash twice with anhydrous ethanol, each time for 5 minutes, then treat with 95% ethanol for 5 minutes, 85% ethanol for 5 minutes, 75% ethanol for 5 minutes, and soak in UP water for 5 minutes;

[0156] Staining: Put the slices in hematoxylin dye for 20 minutes; wash the slices stained with hematoxylin with distilled water until the background of the slices appears light pink; put the slices in acid alcohol, soak for 10 seconds, and wash the slices with distilled water again; put the slices in eosin dye and stain for 5 minutes; wash the slices with distilled water until the water is clear and transparent; soak the slices in 95% and 100% ethanol in turn, soak for 5 minutes each time, and dehydrate twice in total.

[0157] Slice observation: Make the slices transparent and then seal them with neutral resin; collect images and observe the lesions.

[0158] The results are as follows Fig.16 The results showed that the liver structure of mice in the control group was obviously normal, with intact liver tissue capsule, unclear hepatic lobule, neatly arranged hepatic cords, intact central vein endothelium, radial arrangement of hepatocytes around the central vein, intact interlobular arteries, interlobular veins and interlobular bile ducts in the portal area, and no obvious fibrous tissue hyperplasia and inflammatory cell infiltration around them. However, D-galactose exposure caused obvious histological damage. Fig.16 B shows the liver sections of mice in the model group, showing obvious hepatocyte swelling, cytoplasmic vacuolization, ballooning degeneration, and fatty degeneration; the cell cytoplasm contains round lipid droplets of varying sizes, neat edges, and no coloring, and the nucleus is biased to one side; a small amount of inflammatory cell infiltration in the hepatic sinusoids, mainly neutrophils with rod-shaped lobed nuclei. Both doses of TY-Y10 live bacteria and heat-killed bacteria intervention can prevent liver damage, such as the loss of ballooning degeneration and the alleviation of cytoplasmic vacuolization ( Fig.16 D. Fig.16 E. Fig.16 F and Fig.16 G), and the effect was better than that of the positive control group ( Fig.16 E). However, different doses of TY-Y10 had different protective effects on liver tissue. The improvement of the high-dose heat-killed bacteria group was more obvious.

[0159] (3) Determination of inflammation level

[0160] Jiangsu ELISA kit was used to measure serum inflammatory factors, including tumor necrosis factor (TNF-α), interleukin-6 (IL-6) and interferon-γ (IFN-γ).

[0161] The results are as follows:

[0162] The levels of serum inflammatory factor IL-6 in each group of mice were as follows Fig.17As shown, the serum IL-6 level of mice in the model group was significantly higher (p<0.05) than that in the blank group; the serum IL-6 content of mice in the positive control group showed a downward trend compared with the model group, but there was no significant difference; the IL-6 levels of the four TY-Y10 intervention groups were significantly lower than those in the blank group (p<0.05), among which the IL-6 levels of the high-dose live bacteria group and the high-dose heat-killed bacteria group were significantly lower than those of the low-dose live bacteria group and the low-dose heat-killed bacteria group (p<0.05). The results showed that D-galactose-induced oxidative stress in mice can lead to increased IL-6 inflammation levels in mice, and intervention with high and low doses of TY-Y10 live bacteria and heat-killed bacteria can reduce the IL-6 inflammation level in mice, among which the high-dose live bacteria group and the high-dose heat-killed bacteria group had the most significant intervention effects.

[0163] The levels of serum inflammatory factor IFN-γ in each group of mice were as follows Fig.18 As shown, the serum IFN-γ level of mice in the model group was significantly higher (p<0.05) than that in the blank group; the serum IFN-γ level of mice in the positive control group was significantly lower than that in the model group (p<0.05); the IFN-γ levels of the four TY-Y10 intervention groups were significantly lower than those in the positive control group (P<0.05), and the IFN-γ level of the high-dose heat-killed bacteria group was significantly lower than that in the blank group (p<0.05). The results showed that D-galactose-induced oxidative stress in mice can lead to increased IFN-γ inflammation levels in mice, and high- and low-dose live bacteria and heat-killed bacteria interventions of TY-Y10 can reduce the IFN-γ inflammation level in mice, among which the high-dose heat-killed bacteria intervention has the best effect.

[0164] The levels of TNF-α in serum of mice in each group were as follows Fig.19 As shown, the serum TNF-α level of mice in the model group was significantly higher (p<0.05) than that in the blank group; the serum TNF-α content of mice in the positive control group showed a downward trend compared with the model group, but there was no significant difference; the TNF-α levels of the four TY-Y10 intervention groups were significantly lower than those in the positive control group (p<0.05), the TNF-α levels of the low-dose live bacteria group and the high- and low-dose heat-killed bacteria groups were significantly lower than those in the blank group (p<0.05), and the TNF-α levels of the heat-killed bacteria group were significantly lower than those in the live bacteria group (p<0.05). The results showed that D-galactose-induced oxidative stress in mice can lead to increased TNF-α inflammation levels in mice, and high- and low-dose live bacteria and heat-killed bacteria interventions of TY-Y10 can reduce TNF-α inflammation levels in mice, among which the heat-killed bacteria intervention effect is better than that of live bacteria.

[0165] In summary, Lactobacillus plantarum TY-Y10 has high antioxidant activity in vitro and is a heat-killed Lactobacillus plantarum cell that can alleviate oxidative stress-induced liver damage in mice and its application.

[0166] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be covered by the scope of the claims of the present invention.

Claims

1. A Lactobacillus plantarum, characterized in that Its accession number is CGMCCNO.24756.

2. Heat-killed Lactobacillus plantarum, characterized in that Obtained by heat-inactivating the plant lactobacillus according to claim 1.

3. The plant lactobacillus heat-killed bacteria according to claim 2, characterized in that The method for heat inactivation of Lactobacillus plantarum comprises: inoculating Lactobacillus plantarum in a culture medium, culturing at 30-37°C for 18-24 hours, subculturing twice, centrifuging to obtain bacterial sludge, and inactivating the bacterial sludge with high-pressure steam at 80-100°C to obtain heat-inactivated Lactobacillus plantarum bacteria.

4. A culture, characterized in that The method is obtained by culturing the plant lactobacillus according to claim 1.

5. An antioxidant composition, characterized in that The invention comprises any one of the following substances: (a) the Lactobacillus plantarum according to claim 1; (b) the heat-killed Lactobacillus plantarum according to claim 2 or 3; (c) the culture according to claim 4; (d) the culture according to claim 4 after heat inactivation.

6. The antioxidant composition according to claim 5, characterized in that It also includes one or more combinations of probiotics, dietary fiber or antioxidant active compounds.

7. An antioxidant preparation, characterized in that The composition comprises the Lactobacillus plantarum of claim 1 or the heat-killed bacteria of Lactobacillus plantarum of claim 2 or 3 or the culture of claim 4 or the antioxidant composition of claim 5 or 6; and carrier.

8. The antioxidant preparation according to claim 7, characterized in that Preparations include foods, nutritional supplements, health products, cosmetics or medicines.

9. Use of the plant lactobacillus according to claim 1, the heat-killed bacteria of plant lactobacillus according to claim 2 or 3, the culture according to claim 4, or the antioxidant composition according to claim 5 or 6 in the preparation of an antioxidant preparation.

10. The use according to claim 9, characterized in that: The applications include one or more of the following: (a) application in the preparation of a preparation for scavenging DPPH; (b) application in the preparation of a preparation for scavenging hydroxyl radicals; (c) application in the preparation of a preparation with reducing ability; (d) application in the preparation of a preparation for reducing the level of malondialdehyde in serum and liver after oxidative stress; (e) application in the preparation of a preparation for reducing the level of pathological damage in liver tissue after oxidative stress; (f) application in the preparation of a preparation for reducing the level of inflammatory factors in serum after oxidative stress; (g) application in the preparation of a preparation for increasing the level of glutathione in serum and liver after oxidative stress; (h) application in the preparation of a preparation for increasing the activity of superoxide dismutase, catalase and glutathione peroxidase in serum and liver after oxidative stress.

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