Application of a small molecule compound K3G in the treatment of chlamydia infection

Abstract

The present invention belongs to the field of biomedical technologies, and particularly relates to the application of a small molecule compound K3G in the treatment of chlamydia infection. In this application, a small molecule compound that can block the binding of the key pathogenic protein Pgp3 of chlamydia to TNF-α was screened out, and in vivo experiments on animals confirmed that injecting K3G can inhibit the pathogenicity of chlamydia in animals by blocking the binding of Pgp3 to TNF-α, thereby achieving the effect of treating chlamydia infection. This solution is simple, effective, economical and practical, and is not prone to drug resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedicine, and particularly relates to the application of a small molecule compound K3G in the treatment of chlamydia infection. Background Art

[0002] Chlamydia trachomatis (Ct) is a pathogen of a common bacterial sexually transmitted disease (STD), and its urogenital tract infection is one of the important causes of female tubal infertility. After chlamydia infection, the clinical manifestations presented in different infection sites are different. Urogenital system infections usually manifest as non-specific urogenital system inflammations. In mild cases, they are manifested as: urethritis, epididymitis, salpingitis, prostatitis, endometritis, etc. In severe cases, it may lead to ectopic pregnancy, tubal infertility, pelvic inflammatory disease, etc. Extra-urogenital system infections may cause conjunctivitis, interstitial pneumonia, proctitis, pharyngitis, reactive arthritis, etc. At the same time, chlamydia is also considered a risk factor for the development of cervical cancer and is associated with an increased risk of HIV transmission or acquisition. Therefore, infected individuals need early diagnosis and early treatment to prevent the spread of the disease and serious sequelae.

[0003] The plasmid-encoded protein Pgp3 of Chlamydia trachomatis can be secreted into inclusion bodies and the cytoplasm of host cells and is an important virulence factor for pathogenesis. TNF-α is an inflammatory cytokine produced by macrophages / monocytes during acute inflammation and is responsible for various intracellular signal transduction events, leading to cell necrosis or apoptosis.

[0004] In previous studies, the applicant of this application, through the structural analysis of Pgp3 and the use of in vitro affinity detection of protein polypeptides, clarified that Pgp3 can specifically bind to TNF-α. At the same time, it was clarified that after the binding of Pgp3 and TNF-α, it can effectively inhibit TNF-α-induced apoptosis and enhance the inflammatory response.

[0005] Currently, there is no treatment plan for chlamydia by specifically targeting the binding of proteins. The existing traditional treatment plan for chlamydia infection is antibiotic treatment. However, the infection of chlamydia is occult, so long-term persistent infection caused by untimely treatment can lead to a series of complications, and the treatment with antibiotics is prone to drug resistance. In addition, some patients do not recover after antibiotic treatment but enter a latent persistent infection state, and a series of serious complications will still occur subsequently. Summary of the Invention

[0006] To solve the above problems, a small molecule compound that can block the binding of the key pathogenic protein Pgp3 of Chlamydia to TNF-α was screened out in this application. Through in-vivo animal experiments, it was clarified that injecting K3G can inhibit the pathogenicity of Chlamydia in animals by blocking the binding of Pgp3 to TNF-α, thereby achieving the effect of treating Chlamydia infection. This solution is simple, effective, economical and practical, and is not prone to drug resistance.

[0007] To achieve the above object, the technical solution adopted in the present invention is as follows:

[0008] One of the technical solutions provided by the present invention is the application of the small molecule compound K3G in the preparation of a drug for inhibiting or treating Chlamydia infection;

[0009] The small molecule compound K3G is specifically kaempferol-3-O-β-D-glucuronide, and its molecular formula is: C 21 H 18 O 12 ; The structural diagram of K3G is as Figure 1 shown;

[0010] Further, the Chlamydia includes but is not limited to Chlamydia trachomatis and Chlamydia trachomatis murine pneumonia;

[0011] Even further, the Chlamydia is Chlamydia trachomatis;

[0012] Further, the Chlamydia infection includes but is not limited to eye, joint, respiratory system, nervous system, or urogenital system infections;

[0013] Even further, the Chlamydia infection is genital tract infection;

[0014] Further, it is the application of the small molecule compound K3G as an inhibitor for blocking the interaction between TNF-α and Pgp3, and the effect of treating Chlamydia infection is achieved by blocking the interaction between TNF-α and Pgp3;

[0015] Preferably, the drug is an injection, and the interaction between TNF-α and Pgp3 is blocked by intraperitoneal injection.

[0016] Another technical solution provided by the present invention is a drug for inhibiting or treating Chlamydia infection, and the drug contains the small molecule compound K3G;

[0017] Further, the Chlamydia includes but is not limited to Chlamydia trachomatis and Chlamydia trachomatis murine pneumonia;

[0018] Even further, the Chlamydia is Chlamydia trachomatis;

[0019] Further, the drug uses the small molecule compound K3G as an active ingredient;

[0020] Furthermore, the drug also contains one or more pharmaceutically acceptable excipients, such as phosphate buffer solution, etc.;

[0021] Preferably, the drug is an injection.

[0022] Beneficial effects:

[0023] Pgp3 can bind to TNF-α, inhibit the apoptosis induced by it, regulate the growth cycle of host cells, enabling Chlamydia to grow and reproduce in a relatively favorable environment, ultimately leading to long-term persistent infection. Experimental research in this invention has confirmed that K3G can effectively inhibit the infection of Chlamydia trachomatis mouse pneumonitis and Chlamydia trachomatis in the genital tract of mice by blocking the binding of Pgp3 to TNF-α, and can significantly reduce the occurrence of oviduct edema in mice. At the same time, as a small molecule, K3G has unique advantages, such as good permeability and absorbability, stable properties and easy synthesis, etc., which is very suitable for application in the field of clinical treatment. Therefore, this invention has clinical practicability, low cost, and reliable effects. Description of the drawings

[0024] Figure 1 It is the structural diagram of K3G.

[0025] Figure 2 It is the binding diagram of Pgp3 and TNF-α.

[0026] Figure 3 It is the schematic diagram of K3G blocking the binding of Pgp3 to TNF-α.

[0027] Figure 4 It is the kinetic analysis diagram of the binding of Pgp3 and TNF-α.

[0028] Figure 5 It is the kinetic analysis diagram of K3G blocking the binding of Pgp3 to TNF-α.

[0029] Figure 6 It is the diagram of Chlamydia load in the lower genital tract of mice inhibited by K3G against Chlamydia trachomatis mouse pneumonitis

[0030] Among them, A is the immunofluorescence diagram of Chlamydia load in the lower genital tract of mice, and B is the statistical chart of Chlamydia data.

[0031] Figure 7 It is the effect of K3G on reducing hydrosalpinx caused by Chlamydia trachomatis mouse pneumonitis infection.

[0032] Figure 8 It is the effect of K3G on reducing the inflammatory reaction of oviduct caused by Chlamydia trachomatis mouse pneumonitis infection.

[0033] Figure 9Chlamydia load in the lower genital tract of mice at different times after Ct-D infection

[0034] Note: Inclusion bodies were observed and counted under a fluorescence microscope. The chlamydia load in each swab was calculated using a formula, and the calculated IFUs were converted to Log10. One-way ANOVA was used; X-axis: different experimental groups, Y-axis: Log10 IFUs representing the chlamydia load in the lower genital tract of mice; (*, p < 0.05; **, p < 0.01; ***, p < 0.001; ****, P < 0.0001). Detailed implementation manners

[0035] In order to make the purpose, technical solutions and advantages of this patent clearer, the following further details this patent in combination with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this patent and are not used to limit the present invention.

[0036] The plasmid-encoded protein Pgp3 of Chlamydia trachomatis can be secreted into inclusion bodies and the cytoplasm of host cells, and is an important virulence factor for pathogenesis. TNF-α is an inflammatory cytokine produced by macrophages / monocytes during acute inflammation, responsible for various intracellular signal transduction events, leading to cell necrosis or apoptosis.

[0037] In previous studies by the research group of this application, through structural analysis of Pgp3 and in vitro affinity detection of protein polypeptides, it was clarified that Pgp3 can specifically bind to TNF-α. At the same time, it was clarified that after the binding of Pgp3 and TNF-α, it can effectively inhibit TNF-α-induced apoptosis and enhance the inflammatory response.

[0038] This invention further clarified the specific binding of TNF-α and Pgp3 through molecular docking technology. The binding site is located at the C-terminus of the Pgp3 protein structure. A binding structure diagram was simulated and constructed, and small molecule compounds that can bind to both the C-terminus of Pgp3 and TNF-α were screened. Based on multi-faceted evaluations such as docking scores, biological activities, synthesizability, and stability, kaempferol-3-O-β-D-glucuronide (abbreviated as K3G in this application) was finally determined as a blocker to block the interaction between TNF-α and Pgp3.

[0039] The molecular formula of K3G is: C 21 H 18 O 12 , and the structural formula is as Figure 1As shown below. In vitro, the binding of Pgp3 and TNF-α and the inhibitory effect of K3G on their binding were detected and analyzed by applying a Biacore S200 biomolecular interaction analyzer. In vivo, animal experiments confirmed that injecting K3G could inhibit the pathogenicity of Chlamydia in animals. We speculated that K3G exerted its effect by blocking the binding of Pgp3 and TNF-α.

[0040] The animal laboratories of the present invention were respectively established in mice using Chlamydia muridarum (Cm) and Chlamydia trachomatis (Ct). The effect of K3G on the Chlamydia load in the lower genital tract of mice before and after drug administration was examined by Ct. At the same time, Cm and Ct have a high degree of similarity (≥97%) in gene sequence and are also similar in biological characteristics and pathogenicity. The infection and pathological changes caused by Cm in the mouse genital tract are very similar to those caused by Ct in humans. In particular, the hydrosalpinx and inflammatory lesions caused by Cm in mice are extremely similar to the human urogenital tract infections caused by Ct. Therefore, using the mouse genital tract infection model established by Cm to study the pathogenic effect of Ct on the human genital tract has become a conventional method in the field for studying Ct. Therefore, the Cm mouse genital tract infection model is currently often used to explore the immune protection effect of Chlamydia trachomatis and its pathological damage mechanism.

[0041] The present invention will be further explained and illustrated through specific embodiments below. Unless otherwise specified, the reagents and materials used in the following embodiments are all commercially available.

[0042] Example 1 Screening Experiment of Small Molecule Compounds Blocking the Binding of TNF-α and Pgp3

[0043] The protein structures of TNF-α and Pgp3 (PDBID: 4JDM) were retrieved from the Protein Data Bank (PDB) database and saved as PDB format files.

[0044] The screened TNF-α protein molecular structures were respectively docked and bound to the C-terminus and N-terminus of Pgp3 using the software Hex8.0.0. Based on the protein binding structure, small molecule compounds that could structurally bind to TNF-α and Pgp3 and block their binding were screened. The protein binding force was measured using Biacore to clarify the blocking effect of the small molecule compounds, and the data was analyzed and processed using Biacore S200 Control Software.

[0045] The results are as follows:

[0046] (1) As Figure 2As shown, the binding affinity of TNF-α to the C-terminus of Pgp3 (745.06) was significantly higher than that to the N-terminus (453.83). This indicates that the binding site of TNF-α to Pgp3 is mainly located at the C-terminus of Pgp3.

[0047] (2) As Figure 1 shown, the structural diagram of the small molecule compound K3G that can bind to TNF-α and Pgp3 structurally and block their binding. Figure 3 are the surface binding diagram and interaction diagram of K3G with the two proteins. The figure shows that the protein residues at the dominant binding sites after docking are GLU-27, ASN-64, ASN-92, and VAL-123.

[0048] (3) Using the Biacore S200 Control Software, first, the kinetics of the binding of TNF-α to His-Pgp3 was analyzed. The results are Figure 4 shown. The response is expressed in resonance units (RU) and is proportional to the surface mass. The affinity is expressed as KD. The figure shows that as the concentration of TNF-α increases, the signal value increases with a certain saturation trend. The fitted KD (M) value is 8.288e-8, indicating that TNF-α can specifically bind to His-Pgp3.

[0049] Then, TNF-α at 1 mg / mL and K3G at 10 mg / mL were mixed evenly at a mass ratio of 10:1 and pre-incubated in a 37°C constant temperature incubator for 30 min. The resulting mixture was used for kinetic analysis with His-Pgp3. The results are Figure 5 shown. For TNF-α pre-incubated with K3G, as the concentration increases, the signal value shows no obvious trend, indicating that kaempferol-3-O-β-D-glucuronide (K3G) can block the specific binding of TNF-α to His-Pgp3.

[0050] The above kinetic experiments are as follows: Prepare a 5% DMSO running buffer, prepare 4.5% DMSO and 5.8% DMSO stock solutions for concentration calibration. Dilute His-Pgp3 to 500 μM with 1.05×PBS-P solution, and serially dilute TNF-α to concentrations of 50 μM, 25 μM, 12.5 μM, 6.25 μM, 3.125 μM, and 0 μM. Inject them into the channels conjugated with His-Pgp3 protein and blank channels. For the kinetic experiment of K3G blockade, the mixture of TNF-α and small molecule blocker co-incubated 30 minutes in advance was serially diluted to concentrations of 50 μM, 25 μM, 12.5 μM, 6.25 μM, 3.125 μM, 1.56 μM, and 0 μM, and then injected into the channels conjugated with His-Pgp3 protein and blank channels. Use the blank channel for calibration and perform multi-cycle detection.

[0051] Animal experiment verification of the K3G blockade effect in Example 2 (Cm infection model)

[0052] Drug preparation: K3G was purchased from Chengdu Purigen Biotech Co., Ltd., with a CAS number of 22688-78-4. Dissolve the small molecule powder in a small amount of DMSO, and then prepare different concentrations with PBS phosphate buffer. The specific drug concentrations are as follows:

[0053] (1) 0.02 mg / mL K3G;

[0054] (2) 0.2 mg / mL K3G;

[0055] (3) 2 mg / mL K3G;

[0056] (4) PBS: with a concentration of 10 mM and a pH value ranging from 6.0 to 8.0.

[0057] Randomly divide female BALB / c mice aged 4-6 weeks into four groups (8 mice in each group): Cm group (Cm refers to Chlamydia trachomatis murine pneumonia), low-concentration K3G group (0.1 mg / kg), medium-concentration K3G group (1.0 mg / kg), and high-concentration K3G group (10 mg / kg).

[0058] All mice were vaginally inoculated with wild-type Cm to establish a Cm infection model of the reproductive tract. Use a pipette to slowly inject 2×10 5 IFU / mL purified wild-type Cm EBs into the vagina of mice, with a volume of about 10 μL, to ensure that the mice were fully inoculated and infected with Chlamydia. On day 3, detect the Chlamydia load in the lower reproductive tract of each group of mice. The detection by IFA shows that the presence of inclusion bodies proves that all the Cm infection models of the reproductive tract of mice have been successfully infected.

[0059] The day of inoculation was set as D0. 30 minutes before inoculation, according to different groups, each group was intraperitoneally injected with the corresponding drug solution. Thereafter, drugs were administered at a fixed time every day for 14 consecutive days. After 14 days, no more intraperitoneal injections were given, and the mice were fed and watered normally. The specific grouping is as follows:

[0060] Cm group: Intraperitoneally injected with about 100 μL of PBS, and drugs were administered once a day at a fixed time after infection for 14 consecutive days;

[0061] Low-concentration K3G group (0.1 mg / kg): The injection volume for each mouse was calculated according to 0.1 mg (K3G) / kg (mouse body weight) based on the mouse body weight, and 0.02 mg / mL of K3G was intraperitoneally injected. After infection, drugs were administered once a day at a fixed time for 14 consecutive days;

[0062] Medium-concentration K3G group (1.0 mg / kg); The injection volume for each mouse was calculated according to 1.0 mg / kg based on the mouse body weight, and 0.2 mg / mL of K3G was intraperitoneally injected. After infection, drugs were administered once a day at a fixed time for 14 consecutive days;

[0063] High-concentration K3G group (10 mg / kg); The injection volume for each mouse was calculated according to 10.0 mg / kg based on the mouse body weight, and 2 mg / mL of K3G was intraperitoneally injected, and 0.02 mg / mL of K3G was intraperitoneally injected. After infection, drugs were administered once a day at a fixed time for 14 consecutive days;

[0064] On the 3rd, 7th, 14th, 21st, 28th, and 35th days after inoculation, exfoliated cells from the lower genital tract of mice were collected respectively for in vitro cell culture and IFA detection to clarify the chlamydia load in the lower genital tract of mice. On the 60th day after infection, the intact genital tract of mice was isolated, the degree of hydrosalpinx in the fallopian tubes of mice was scored macroscopically, and pathological sections were stained with H&E to evaluate the degree of dilation and inflammatory infiltration of the fallopian tubes. Through this evaluation, the inhibitory effect of the blocker on the pathogenicity of Pgp3 was clarified. The experimental results are as follows:

[0065] (1)The chlamydia load in the lower genital tract of mice was detected on the 3rd, 7th, 14th, 21st, 28th, and 35th days after mouse infection. As Figure 6 shown ( Figure 6 in which A is the immunofluorescence image of chlamydia load in the lower genital tract of mice, Figure 6In Figure B (the statistical chart of chlamydia data), on the 3rd, 7th, 14th, and 21st days after chlamydia infection, the number of IFU in the lower genital tract of mice in each group after K3G intervention, namely the 0.1 mg / kg group, 1.0 mg / kg group, and 10.0 mg / kg group, was significantly lower than that in the Cm group (P < 0.05). However, there was no obvious difference in the number of IFU among the K3G intervention groups with different concentrations. On the 28th day after infection, chlamydia was not detected in the exfoliated cells of the lower genital tract of mice in each group injected with K3G intraperitoneally. On the 35th day after infection, chlamydia was not detected in the lower genital tract of mice in the Cm group.

[0066] From the above results, it can be seen that injecting K3G intraperitoneally can inhibit chlamydia infection and significantly shorten the clearance period of chlamydia. Combining Figure 4 - Figure 5 with the kinetic experiment, it was further determined that K3G inhibited the infection by blocking the binding of Pgp3 to TNF-α.

[0067] (2) After mice were inoculated vaginally and infected with Cm, hydrosalpinx could be caused by ascending infection. Each group of mice was sacrificed 60 days after infection, and the reproductive tracts of the mice were completely dissected. The severity of hydrosalpinx was observed macroscopically and evaluated according to the scoring criteria. As Figure 7 shown, obvious hydrosalpinx could be observed in the Cm group. The scoring results of hydrosalpinx in each group injected with K3G intraperitoneally were significantly lower than those in the Cm group. There was no obvious difference in the hydrosalpinx scores among the groups injected with different concentrations of K3G. From the results, it can be seen that injecting K3G intraperitoneally can reduce hydrosalpinx caused by chlamydia infection.

[0068] Scoring criteria for the severity of hydrosalpinx: If no hydrosalpinx is observed in the fallopian tube macroscopically, it is recorded as 0 point; if the hydrosalpinx in the fallopian tube cannot be clearly identified macroscopically and needs to be observed under a magnifying glass, it is recorded as 1 point; if the hydrosalpinx in the fallopian tube can be clearly observed macroscopically, but the size of the hydrosalpinx at the lesion is smaller than the ipsilateral ovary, it is recorded as 2 points; if the hydrosalpinx in the fallopian tube can be clearly observed macroscopically, but the size of the hydrosalpinx at the lesion is equal to the ipsilateral ovary, it is recorded as 3 points; if the hydrosalpinx in the fallopian tube can be clearly observed macroscopically, but the size of the hydrosalpinx at the lesion is larger than the ipsilateral ovary, it is recorded as 4 points.

[0069] (3) After mice were infected with chlamydia, in addition to hydrosalpinx, reactions such as fallopian tube dilation and inflammatory cell infiltration in the fallopian tube could also be induced. The fallopian tube sections of each group of mice were stained with H&E, and the pathological changes of the fallopian tube tissues of each group of mice were observed under the microscope.

[0070] As Figure 8 shown, when different concentrations of K3G were injected intraperitoneally into mice, there was no obvious infiltration of inflammatory cells and dilation of the lumen in their fallopian tubes. However, obvious infiltration of inflammatory cells could be seen in the fallopian tubes of mice in the Cm group, and different degrees of lumen dilation, thinning, reduction of mucosal folds, and disappearance of apical cilia occurred.

[0071] According to the fallopian tube dilation score and the inflammatory cell infiltration degree score, it can be seen that the fallopian tube dilation degree score and the inflammatory infiltration degree score of each group injected with K3G intraperitoneally are significantly lower than those of the Cm group, and there is no obvious difference in the fallopian tube dilation and inflammatory infiltration degrees among the groups injected with different concentrations of K3G. From the results, it can be seen that intraperitoneal injection of K3G can reduce the fallopian tube inflammatory reaction induced by chlamydia infection.

[0072] Fallopian tube dilation scoring criteria: Under the microscope, if there is no obvious dilation of the fallopian tube, it is recorded as 0 points; if a single dilated cross-section is observed, it is recorded as 1 point; if 1 to 3 dilated cross-sections are observed, it is recorded as 2 points; if more than 3 dilated cross-sections are observed, it is recorded as 3 points; if obvious fusion dilation is observed, it is recorded as 4 points.

[0073] Fallopian tube inflammatory cell infiltration degree scoring criteria: Under the microscope, if there is no obvious inflammatory cell infiltration in the fallopian tube, it is recorded as 0 points; if inflammatory infiltration appears in a single lesion, it is recorded as 1 point; if inflammatory infiltration appears in 2 to 4 lesions, it is recorded as 2 points; if inflammatory infiltration appears in more than 4 lesions, it is recorded as 3 points; if inflammatory infiltration foci appear in the entire fallopian tube wall, it is recorded as 4 points.

[0074] Animal experiment verification of the blocking effect of K3G in Example 3 (Ct infection model)

[0075] 1. Grouping and model construction of mice

[0076] Drug preparation: K3G was purchased from Chengdu Bioscience Co., Ltd., and the CAS number is 22688-78-4. The small molecule powder was dissolved in a small amount of DMSO and then configured into different concentrations with PBS phosphate buffer. The specific drug concentrations are as follows:

[0077] (1) 0.02 mg / mL K3G;

[0078] (2) 2 mg / mL K3G;

[0079] (3) PBS: The concentration is 10 mM, and the pH value ranges from 6.0 to 8.0.

[0080] After female SPF-grade BALB / c mice aged 4-6 weeks were adaptively fed for 1 week, the mice were randomly divided into 3 groups, with 6 mice in each group, labeled as the Ct-D (Ct-D refers to Chlamydia trachomatis serotype D) group, the low-concentration K3G group (0.1 mg / kg), and the high-concentration K3G group (10 mg / kg).

[0081] Five days before mouse infection, progesterone was subcutaneously injected into each mouse according to its body weight, with an injection volume of approximately 2.5 mg, to synchronize the mouse physiological cycle and increase the susceptibility of mice to EB. One day before the mice were inoculated with Chlamydia EB, the vaginal secretions of the mice were cleaned with a male swab, and the exfoliated vaginal epithelial cells were gently scraped to avoid the influence of excessive secretions on the Ct-D infection process. Five days after the progesterone injection was completed, all mice were inoculated with Chlamydia trachomatis (Ct-D) in the reproductive tract. The inoculation day was set as D0. The purified Ct-D: EBs were diluted with ice-cold SPG, and each mouse was inoculated with 20 µL of 2×10 6 IFU / mL of EBs. The chlamydia load in the lower reproductive tract of each group of mice was detected on D3, and the presence of inclusions detected by IFA proved that all the Ct-D infection models in the reproductive tract of the mice were successfully infected.

[0082] Thirty minutes before inoculation, according to different groups, each group was intraperitoneally injected with the corresponding drug solution, and then the drug was administered at a fixed time every day for 14 days. After 14 days, intraperitoneal injection was no longer performed, and the mice were fed with normal food and water. The specific grouping is as follows:

[0083] Ct-D group: Intraperitoneally injected with approximately 100 μL of PBS, and the drug was administered once a day at a fixed time after infection for 14 consecutive days;

[0084] Low-concentration K3G group (0.1 mg / kg): The injection volume for each mouse was calculated according to 0.1 mg (K3G) / kg (mouse body weight) based on the mouse body weight, and 0.02 mg / mL of K3G was intraperitoneally injected. The drug was administered once a day at a fixed time after infection for 14 consecutive days.

[0085] High-concentration K3G group (10 mg / kg); The injection volume for each mouse was calculated according to 10 mg (K3G) / kg (mouse body weight) based on the mouse body weight, and 2.0 mg / mL of K3G was intraperitoneally injected. The drug was administered once a day at a fixed time after infection for 14 consecutive days;

[0086] 2. Detection of chlamydia load

[0087] On the 3rd, 7th, 14th, and 21st days after chlamydia infection, the vaginal exfoliated cells of the mice were taken respectively for in vitro cell culture and IFA detection to clarify the chlamydia load in the vagina of the mice. The results are as follows:

[0088] (1) In this experiment, mice were infected with Chlamydia trachomatis serotype D, and the chlamydia load in the reproductive tract of the mice was detected on the 3rd, 7th, 14th, and 21st days after infection. The results are as Figure 9 shown: On the 3rd, 7th, 14th, and 21st days after infection, both the 0.1 mg / kg group and the 10 mg / kg group were significantly lower than the Ct-D group (p<0.001), but there was no obvious difference between the different concentration K3G intervention groups.

[0089] (2)Twenty-one days after infection, Chlamydia was not detected in the genital tracts of the two groups of mice intervened with K3G; twenty-eight days after infection, Chlamydia was not detected in the genital tracts of the mice in the Ct-D group, indicating that intraperitoneal injection of K3G can inhibit Chlamydia infection and shorten the Chlamydia clearance period by blocking the binding of Pgp3 to TNF-α.

[0090] The above-described embodiments merely represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed. However, it should not be construed as a limitation on the scope of the patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of this patent, several deformations, combinations, and improvements can be made to the above-mentioned implementation manners, and these all fall within the protection scope of this patent. Therefore, the protection scope of this patent shall be subject to the claims.

Claims

1. Use of compound K3G in the preparation of a drug for inhibiting or treating chlamydia infection, characterized in that, The compound K3G is kaempferol-3-O-β-D-glucuronide, and its molecular formula is: C 21 H 18 O 12 .

2. The application according to claim 1, characterized in that The chlamydia is: Chlamydia trachomatis or Chlamydia trachomatis murine pneumonitis.

3. The application according to claim 1, characterized in that The chlamydia infection is a chlamydia infection of the eye, joints, respiratory system, nervous system, or urogenital system.

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