Benzenesulfonyl indole structure modified ruthenium polypyridine complex capable of inhibiting bacterial toxins as well as preparation method and application of benzenesulfonyl indole structure modified ruthenium polypyridine complex

Abstract

The invention belongs to the technical field of antibacterial medicines, and particularly relates to a benzenesulfonyl indole structure modified ruthenium polypyridine complex capable of inhibiting bacterial toxins as well as a preparation method and application of the benzenesulfonyl indole structure modified ruthenium polypyridine complex. The ruthenium polypyridine complex with the benzenesulfonyl indole structure, disclosed by the invention, has the following structure: # imgabs0 #; the ruthenium polypyridine complex with the benzenesulfonyl indole structure, disclosed by the invention, not only shows excellent antibacterial ability, but also does not show drug resistance for inducing bacteria. The ruthenium polypyridine complex with the benzenesulfonyl indole structure, disclosed by the invention, can be combined with polymyxin B to play a better antibacterial effect. In addition, research finds that the ruthenium polypyridine complex with the benzenesulfonyl indole structure has a certain anti-biofilm effect, and the action mechanism of the ruthenium polypyridine complex is further researched. The complex can also effectively inhibit the hemolysis phenomenon caused by bacteria, and shows concentration dependence.

Description

Technical Field

[0001] The invention belongs to the technical field of antibacterial medicine, and specifically relates to a benzenesulfonyl indole structure-modified ruthenium polypyridine complex for inhibiting bacterial toxins, and a preparation method and application thereof. Background Art

[0002] As the problem of antibiotic abuse worsens, drug-resistant bacterial infections have become a major challenge to global public health. According to reports from the World Health Organization (WHO) and public health departments of various countries, the incidence and mortality of drug-resistant bacterial infections are increasing year by year. The global antimicrobial drug market is huge, and as the problem of drug-resistant bacteria worsens, the demand for new antimicrobial drugs will continue to grow.

[0003] Combination antibiotics refer to the use of two or more antibiotics at the same time to treat an infection. When the pathogen of an infection is unclear, combination antibiotics can cover a wider range of bacterial species and ensure effective treatment. Certain combinations of antibiotics can enhance the antibacterial effect, such as the combination of β-lactams and aminoglycosides, which are often used to treat serious infections. Combination antibiotics can reduce the risk of bacterial resistance, especially when treating infections that are prone to drug resistance, such as tuberculosis.

[0004] Bacterial biofilms are structured communities of bacteria formed on surfaces, wrapped in their own secreted extracellular polymers. These extracellular polymers are mainly composed of polysaccharides, proteins, DNA and lipids, which provide protection and stability to the bacteria. Biofilms are associated with a variety of chronic infections, such as lung infections in patients with cystic fibrosis, chronic wound infections, urinary tract infections, etc. These infections are difficult to cure and are prone to recurrence. Bacteria in biofilms are much more resistant to antibiotics than planktonic bacteria, making them difficult to treat. Hemolysis is the process by which red blood cells rupture and hemoglobin is released. Bacterial infection can cause hemolysis through toxins, enzymes, immune responses, or direct invasion of red blood cells.

[0005] Therefore, how to prepare substances that can inhibit bacterial toxins, inhibit hemolysis caused by bacteria and remove bacterial biofilms is a technical problem that needs to be solved urgently. Summary of the invention

[0006] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a ruthenium polypyridine complex having a benzenesulfonyl indole structure and a preparation method and application thereof.

[0007] The technical solution of the present invention is as follows: The first aspect of the present invention provides a benzenesulfonyl indole structure-modified ruthenium polypyridine complex having the ability to inhibit bacterial toxins, which has a structure as shown in Formula I: Formula I; Wherein, in Formula I Has one of the following structures:

[0008] The ruthenium polypyridine complex of the benzenesulfonyl indole structure of the present invention has a unique antibacterial mechanism. The ruthenium ions in the complex carry a positive charge and can interact with the negatively charged bacterial cell membrane through electrostatic interaction. This interaction causes the cell membrane phospholipid bilayer structure to be destroyed, thereby causing the leakage of intracellular substances, inhibiting the production of bacterial toxins, and ultimately achieving the effect of inhibiting bacterial growth. In addition, the multi-coordinated configuration characteristics of the ruthenium complex enable it to be modified with a variety of ligands, which not only enhances its biological activity, but also reduces its toxicity, thereby improving its application value as an antibacterial agent.

[0009] The second aspect of the present invention provides a method for preparing the above-mentioned benzenesulfonyl indole structure-modified ruthenium polypyridine complex for inhibiting bacterial toxins, comprising the following steps: The main ligand as shown in formula a and the auxiliary ligand as shown in formula b are dissolved in a solvent, and a coordination substitution reaction is carried out under a protective atmosphere to introduce the main ligand into the auxiliary ligand to obtain a ruthenium polypyridine complex with a benzenesulfonyl indole structure as shown in formula I; Its synthetic route is as follows: Wherein, formula b and formula I Has one of the following structures: The present invention uses a ruthenium complex as an auxiliary ligand and utilizes its unique physicochemical properties to achieve antibacterial function. Ruthenium, as a transition metal, has complexes that not only have good biocompatibility, excellent electrochemical and photophysical properties, but can also be combined with small molecule compounds and nanomaterials. Thanks to the rigid octahedral geometric structure of the ruthenium complex, it is easy to carry out structural modification and exhibits a high degree of plasticity. In addition, after the introduction of the benzenesulfonyl indole structure, the antibacterial activity may be significantly improved. The benzenesulfonyl indole structure may enhance the selectivity of the compound to bacteria by interacting with specific bacterial targets (such as enzymes or proteins), thereby enhancing the antibacterial effect. The hydrophobicity of benzenesulfonyl indole may help the compound to better penetrate the bacterial cell membrane and increase its accumulation in the cell, thereby more effectively destroying the internal structure or metabolic process of the bacteria. The benzenesulfonyl indole structure may interfere with the metabolic pathway or signal transduction of bacteria, inhibit the synthesis and release of bacterial toxins, and reduce the pathogenicity of bacteria. Benzenesulfonyl indole and the ruthenium complex produce a synergistic effect, further enhancing the antibacterial activity while reducing the development of bacterial resistance. The invention modifies the polypyridine ruthenium complex with a benzenesulfonyl indole structure, thereby significantly enhancing its ability to penetrate bacterial cell membranes and retention effect, thereby destroying bacterial membrane structures, inhibiting the production of bacterial toxins, and achieving an antibacterial effect.

[0010] Specifically, the chemical formula of the auxiliary ligand is Ru(bpy)2Cl2·2H2O, Ru(dtb)2Cl2·2H2O, Ru(dmb)2Cl2·2H2O or Ru(dmp)2Cl2·2H2O; the Ru(bpy)2Cl2·2H2O has a structure as shown in formula c-1; the Ru(dtb)2Cl2·2H2O has a structure as shown in formula c-2; the Ru(4,4′-Ru(dmb)2Cl2·2H2O has a structure as shown in formula c-3; the Ru(dmp)2Cl2·2H2O has a structure as shown in formula c-4.

[0011] Preferably, the molar ratio of the primary ligand to the auxiliary ligand is 1:0.8~1.0.

[0012] Preferably, the temperature of the coordination substitution reaction is 140° C. to 160° C., and the time is 7 h to 9 h.

[0013] Preferably, the method for preparing the primary ligand comprises the following steps: The compound shown in formula d and the compound shown in formula e are mixed, and a ketoaldehyde condensation reaction occurs under acid catalysis to form a main ligand containing benzenesulfonyl indole; Its synthetic route is as follows: .

[0014] Preferably, ammonium acetate is also added and mixed together; the acid is acetic acid.

[0015] During the reaction, ammonium acetate will undergo a certain degree of dissociation to produce ammonium ions, which will react with benzenesulfonyl indole in a nucleophilic addition reaction, and then form an imine product through a dehydration reaction. At the same time, the nitrogen atom of the imine will attack the carbonyl carbon of 1,10-phenanthroline-5,6-dione to form a new negatively charged oxygen intermediate. The negatively charged oxygen intermediate can react with another carbonyl group of 1,10-phenanthroline-5,6-dione through intramolecular electron transfer and proton transfer processes to form a new carbon-oxygen bond. At the same time, a double bond is formed between the nitrogen atom and the other carbonyl carbon, and an intramolecular cyclization reaction occurs to generate a product containing a heterocyclic structure, thereby obtaining a primary ligand containing benzenesulfonyl indole.

[0016] Preferably, the molar ratio of the compound represented by formula d to the compound represented by formula e is 0.9-1.1:1.0-1.2. Preferably, the temperature of the ketoaldehyde condensation reaction is 110° C.-130° C., and the time is 3 h-5 h.

[0017] The third aspect of the present invention provides a use of the above-mentioned ruthenium polypyridine complex with a benzenesulfonyl indole structure in the preparation of an anti-Staphylococcus aureus product and / or a product for eradicating biofilm formed by Staphylococcus aureus.

[0018] The present invention explores the effect on biofilm. Bacterial biofilm is a structured community formed by bacteria on the surface, wrapped in the extracellular polymer (EPS) secreted by itself. Biofilm is associated with a variety of chronic infections, such as lung infections, chronic wound infections, urinary tract infections, etc. in patients with cystic fibrosis. These infections are difficult to cure and prone to recurrence. Bacteria in biofilms are much more resistant to antibiotics than planktonic bacteria, making treatment difficult. Crystal violet staining is used, and crystal violet can dye biofilms. The effect of the drug on biofilm can be reflected by observing the color degree of crystal violet. The present invention shows an excellent anti-biofilm effect. As the drug concentration increases, the anti-biofilm activity is further enhanced. Vancomycin is a glycopeptide antibiotic, mainly used to treat severe infections caused by Gram-positive bacteria. Vancomycin exerts its antibacterial effect by inhibiting the synthesis of bacterial cell walls. It specifically binds to D-alanyl-D-alanine at the end of the bacterial cell wall precursor peptidoglycan, preventing the extension and cross-linking of the peptidoglycan chain, thereby causing incomplete bacterial cell wall structure and ultimately causing bacterial death. In order to further demonstrate the advantages of the present invention, by using vancomycin for comparison, it can be seen that the present invention has excellent performance, and as the concentration increases, the anti-biofilm effect of the present invention is basically the same as that of vancomycin.

[0019] The fourth aspect of the present invention provides an application of the above-mentioned ruthenium polypyridine complex with a benzenesulfonyl indole structure in combination with an antibiotic in the preparation of an anti-Escherichia coli product.

[0020] The present invention has a combined effect with other antibiotics. When used in combination with polymyxin B, it can effectively fight against Escherichia coli infection, reduce the dosage of a single antibiotic, and reduce side effects. When the infectious pathogen is unclear, the combined use of antibiotics can cover a wider range of bacterial species, ensure effective treatment, and is suitable for mixed infections caused by multiple bacteria. The combined use of antibiotics can reduce the probability of bacterial resistance, especially in the treatment of infections that are prone to drug resistance, such as tuberculosis. Different antibiotics act on bacteria through different mechanisms, reducing the selection pressure of drug-resistant strains.

[0021] Preferably, the antibiotic is polymyxin B.

[0022] Preferably, the product comprises a medicine or an antimicrobial agent.

[0023] The present invention has at least one of the following beneficial effects: The present invention uses a ruthenium complex as an auxiliary ligand and utilizes its unique physicochemical properties to achieve antibacterial function. Ruthenium, as a transition metal, has complexes that not only have good biocompatibility, excellent electrochemical and photophysical properties, but can also be combined with small molecule compounds and nanomaterials. Thanks to the rigid octahedral geometric structure of the ruthenium complex, it is easy to carry out structural modification and exhibits a high degree of plasticity. The polypyridine structure is a typical nitrogen-containing heterocyclic compound, which enables it to have more targets, thereby destroying the bacterial cell membrane and inhibiting the production of bacterial toxins. In addition, after the introduction of the benzenesulfonyl indole structure, the antibacterial activity may be significantly improved. The benzenesulfonyl indole structure may enhance the selectivity of the compound to bacteria by interacting with specific bacterial targets (such as enzymes or proteins), thereby enhancing the antibacterial effect. Through structural optimization, benzenesulfonyl indole modification may improve the biocompatibility of the compound and reduce the toxicity to the host cell, thereby improving its safety as an antibacterial agent. The benzenesulfonyl indole structure may reduce the existing antibiotic resistance problem by acting on non-traditional targets of bacteria, and provide a new solution for combating drug-resistant bacteria. The present invention develops a new type of benzenesulfonyl indole structure-modified ruthenium polypyridine complex that inhibits bacterial toxins, and provides a preparation method and application thereof. Antibacterial experiments and drug resistance experiments show that this new synthetic benzenesulfonyl indole structure ruthenium polypyridine complex has good antibacterial activity and drug resistance, and is expected to become a new and effective antibiotic against Staphylococcus aureus. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the H NMR spectrum of Ru-2.

[0025] Figure 2This is the mass spectrum of Ru-2.

[0026] Figure 3 The antibacterial effect of Ru-2 complex on Staphylococcus aureus after treatment with different concentrations and for different time periods.

[0027] Figure 4 The Ru-2 complex is used in combination with polymyxin B to fight against Escherichia coli infection.

[0028] Figure 5 It is a comparison of the effects of Ru-2 complex and vancomycin against biofilm formed by Staphylococcus aureus.

[0029] Figure 6 It is the DNA leakage of Staphylococcus aureus under the action of Ru-2 complex.

[0030] Figure 7 It is the protein leakage of Staphylococcus aureus under the action of Ru-2 complex.

[0031] Figure 8 It is the hemolysis rate of the Ru-2 complex at different concentrations of the present invention on Staphylococcus aureus. DETAILED DESCRIPTION

[0032] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] In the description of the present invention, unless otherwise specified, all reagents used are commercially available and all methods used are conventional techniques in the art.

[0034] Example 1 This embodiment provides a method for preparing a benzenesulfonyl indole structure-modified ruthenium polypyridine complex for inhibiting bacterial toxins.

[0035] (1) Preparation of primary ligand: 208.0 mg of 1,10-phenanthroline-5,6-dione (Formula d), 210.6 mg of benzenesulfonyl indole (Formula e) and 2300.4 mg of ammonium acetate were weighed and placed in a 250 mL three-necked bottle, and 65 ml of acetic acid was added, and refluxed and stirred at 120° C. for 4 h; after the reaction solution was cooled, water was added to dilute it, and the pH was adjusted to neutral with ammonia water to precipitate a yellow precipitate; the precipitate was filtered under reduced pressure, and then separated and purified by silica gel column chromatography using ethanol as an eluent to obtain a pure product, and vacuum dried to obtain the main ligand shown in Formula a, with a yield of 62%; its preparation reaction route is as follows: (2) Preparation of ruthenium polypyridine complexes with benzenesulfonyl indole structure: In a 50mL three-necked flask, 108.7mg of the main ligand shown in formula a and 100.3mg of Ru(dtb)2Cl2·2H2O (formula c-2) were added and dissolved in ethylene glycol; under the protection of argon, the mixture was stirred and refluxed at 150°C for 8h. After the reaction was completed, the mixture was cooled to room temperature, and a saturated potassium hexafluorophosphate solution was added to precipitate a large amount of red-brown solid; the precipitate was filtered and collected, and vacuum dried to obtain a crude product; the crude product was separated and purified by a neutral alumina column using a mixed solution of xylene and acetonitrile as a concentration gradient eluent; wherein the volume ratio of xylene to acetonitrile was 10:1, and a benzenesulfonyl indole-modified polypyridine ruthenium complex was obtained, recorded as Ru-2, with a yield of 68%; its preparation reaction route is shown as follows: Among them, the structural formula of Ru(dtb)2Cl2·2H2O is shown in c-2.

[0036] In addition, the Ru(dtb)2Cl2·2H2O in step (2) was replaced by Ru(bpy)2Cl2·2H2O, Ru(dmb)2Cl2·2H2O or Ru(dmp)2Cl2·2H2O, respectively. The other steps were the same as the preparation process of Ru-2, and three other benzenesulfonyl indole-modified polypyridine ruthenium complexes were prepared, which were respectively recorded as Ru-1, Ru-3 and Ru-4.

[0037] Among them, the structural formulas of Ru(bpy)2Cl2·2H2O, Ru(dmb)2Cl2·2H2O or Ru(dmp)2Cl2·2H2O are shown in c-1, c-3 and c-4 respectively.

[0038] The prepared product Ru-2 was characterized by nuclear magnetic hydrogen spectrum and mass spectrum. Figure 1 , 2 As shown: 1 HNMR (400MHz, DMSO) δ69.00(s, 2H), 8.87 (d, J = 15.3 Hz, 5H), 8.11 - 8.01(m, 3H), 7.83(s, 3H), 7.70 (t, J = 6.3 Hz, 3H), 7.66 - 7.59(m, 4H), 7.46 (d, J = 5.9 Hz, 4H),7.35 (d, J = 6.0 Hz,2H), 7.11 (d, J= 7.2 Hz, 1H), 7.05 (d, J = 6.0, 2.9 Hz, 1H),6.99 - 6.93 (m, 1H), 1.42 (d, J = 1.5Hz, 18H), 1.33(d, J = 1.5 Hz, 18H). The MIC values ​​of Ru-1, Ru-2, Ru-3 and Ru-4 were determined as follows: Staphylococcus aureus strains were cultured in TSB medium until the logarithmic growth phase; the suspension was diluted 1000 times with fresh medium to obtain a bacterial suspension. 50 µL of different concentrations of Ru-2 were added to the 96-well plate in turn, and then 200 µL of bacterial suspension was added to each well, so that the final concentration of Ru-2 in each well was 100 µg / mL, 50 µg / mL, 25 µg / mL, 12.5 µg / mL, 6.25 µg / mL, 3.125 µg / mL, 1.56 µg / mL, 0.78 µg / mL, and 0.39 µg / mL from left to right. 50 µL of sterile water was added to the last well as a blank control. Each drug was tested in 3 parallel groups. After incubation at 37°C for 20 h, the bacterial growth was monitored by observing the turbidity of the culture. The lowest drug concentration corresponding to the clear dosing well was the MIC (minimum inhibitory concentration).

[0039] The MIC values ​​of Ru-1, Ru-3 and Ru-4 were determined in the same manner as above.

[0040] The MIC values ​​of Ru-1, Ru-2, Ru-3 and Ru-4 were determined to be 3.5 μg / mL, 1.56 μg / mL, 5.0 μg / mL and 12.5 μg / mL, respectively.

[0041] Example 2 This example provides DNA leakage and protein leakage experiments of the benzenesulfonyl indole-modified polypyridine ruthenium complex Ru-2 prepared in Example 1.

[0042] Staphylococcus aureus was revived and cultured in TSB liquid medium at 37°C for 24 hours. The bacterial population density was determined by measuring the absorbance at a wavelength of 600 nm using a microplate reader. The bacteria were treated specifically to induce cell membrane damage. The cell culture medium was centrifuged and the supernatant was collected. The DNA / protein content in the supernatant was measured using a spectrophotometer. The amount of DNA / protein leakage between the different treatment groups was compared to assess the degree of cell membrane damage.

[0043] The specific treatment methods of different treatment groups are as follows: Ru-2 group: take OD 600Prepare Ru-2 with a final concentration of 1.56µg / mL and 3.125µg / mL for 0.3 of Staphylococcus aureus, incubate for 2-4 hours, and measure the absorbance of the supernatant at 260nm and 280nm after centrifugation.

[0044] Polymyxin B group: OD 600 Prepare polymyxin B with a final concentration of 1.56µg / mL and 3.125µg / mL for 0.3 S. aureus, incubate for 2-4 hours, and measure the absorbance of the supernatant at 260nm and 280nm after centrifugation.

[0045] Control group: OD 600 The concentration of Staphylococcus aureus was 0.3, incubated for 2-4 hours, and the absorbance of the supernatant was measured at 260nm and 280nm after centrifugation.

[0046] The degree of cell membrane damage is Figure 6 and Figure 7 As shown by Figure 6 and Figure 7 It can be seen that the OD of Ru-2 group 260 OD 280 Both were greater than polymyxin B and the control group, indicating that Ru-2 had a stronger destructive effect on the cell membrane, causing the DNA and proteins in the cells to flow out, which also showed that Ru-2 exerted its antibacterial effect by destroying the cell membrane.

[0047] The present invention explores the antibacterial mechanism of the prepared benzenesulfonyl indole-modified ruthenium polypyridine complex. In order to explore the antibacterial mechanism of the present invention, DNA leakage detection and protein leakage detection were carried out. DNA leakage can detect the integrity of the cell membrane, and the degree of damage to the cell membrane can be indirectly evaluated by detecting the DNA content in the extracellular medium. Protein leakage is another verification experiment for cell membrane damage. After the cell membrane is destroyed, the substance in the membrane flows out, and the integrity of the membrane can also be reflected by detecting the protein content in the extracellular medium. The present invention uses polymyxin B as a control. At the same concentration, the present invention has a stronger destructive effect on the cell membrane, and the DNA and protein in the cell flow out, which also shows that the present invention exerts an antibacterial effect by destroying the cell membrane. The hydrophobicity of benzenesulfonyl indole may help the compound to better penetrate the bacterial cell membrane, increase its accumulation in the cell, and thus more effectively destroy the internal structure or metabolic process of the bacteria. The benzenesulfonyl indole structure may interfere with the metabolic pathway or signal transduction of bacteria, inhibit the synthesis and release of bacterial toxins, and reduce the pathogenicity of bacteria. Benzenesulfonyl indole and ruthenium complex produce a synergistic effect, further enhancing the antibacterial activity and reducing the development of bacterial resistance. The present invention modifies the polypyridine ruthenium complex by the benzenesulfonyl indole structure, significantly enhancing its ability to penetrate the bacterial cell membrane and retention effect, thereby destroying the bacterial membrane structure, inhibiting the production of bacterial toxins, and achieving an antibacterial effect.

[0048] Example 3 This example provides an experiment on the use of the benzenesulfonyl indole-modified polypyridyl ruthenium complex Ru-2 prepared in Example 1 to fight against the biofilm formed by Staphylococcus aureus.

[0049] In the crystal violet staining method, S. aureus was diluted into TSB at a concentration of 10 7 CFU mL −1 . Subsequently, 1 mL of bacterial solution was added to the 24-well plate and incubated at 37°C for 24 hours. After the incubation was completed, the plates were washed three times with PBS and then subjected to different treatment groups. After treatment, the plates were washed again with PBS and dried for 30 minutes. The next step was staining with 5% (v / v) crystal violet solution for 1 hour, followed by the addition of 33% (v / v) acetic acid after removing the staining solution. Finally, the absorbance value was measured at 595 nm.

[0050] The specific treatment methods of different treatment groups are as follows: Ru-2 group: Ru-2 was prepared with final concentrations of 1.56µg / mL, 3.125µg / mL, 6.25µg / mL, 12.5µg / mL, 25µg / mL, and 50µg / mL and added to a 24-well plate and incubated for 24 hours.

[0051] Vancomycin group: Vancomycin was prepared with final concentrations of 1.56µg / mL, 3.125µg / mL, 6.25µg / mL, 12.5µg / mL, 25µg / mL, and 50µg / mL and added to a 24-well plate and incubated for 24 hours.

[0052] Control group: PBS was added and incubated for 24 hours. The results are as follows Figure 5 As shown, Figure 5 The effect of Ru-2 complex and vancomycin on biofilm formed by Staphylococcus aureus is compared. Figure 5 It can be seen that the OD of Ru-2 group 595 It is smaller than the control group and equivalent to the vancomycin group, which indicates that the Ru-2 complex has the ability to eradicate the biofilm formed by Staphylococcus aureus, and the effect is equivalent to that of the vancomycin group. It also shows that the Ru-2 complex can penetrate the biofilm and better exert its antibacterial ability.

[0053] Example 4 This example provides a hemolytic experiment of the benzenesulfonyl indole-modified polypyridine ruthenium complex Ru-2 prepared in Example 1.

[0054] Erythrocytes were obtained from the eyes of a healthy 6-week-old male BALB / c mouse. Subsequently, the erythrocytes were centrifuged at 8000 rpm for 5 min, the supernatant was removed, and the erythrocytes were washed three times with PBS before dilution for further use. The diluted erythrocytes, bacteria, and concentrations ranging from 0 to 0.9 μg mL -1 of Ru-2. TX-100 and PBS were used as positive and negative controls, respectively. The mixture was incubated at 37°C for 30 minutes and then centrifuged again at 8000 rpm for 5 minutes. The absorbance of the supernatant was measured at a wavelength of 540 nm to evaluate the hemolysis rate, and the calculation formula was as follows: Hemolysis rate (%) = (Ah – An) / (Ap – An) × 100%. In this formula, Ah, Ap, and An represent the absorbance values ​​of the supernatant of the Ru-2 group, the positive control group, and the negative control group, respectively.

[0055] The results are as follows Figure 8 As shown, Figure 8 is the hemolysis rate of Ru-2 complex at different concentrations. Figure 8 As shown, by OD 543nm The absorbance quantitative detection concentration was 0.3 μg mL -1 , 0.6 μg mL -1 and 0.9 μg mL -1 The Ru-2 complex has the effect of inhibiting the hemolysis of Staphylococcus aureus and the production of Staphylococcus aureus toxins in a concentration-dependent manner.

[0056] Example 5 This example provides an antibacterial experiment of the benzenesulfonyl indole-modified polypyridine ruthenium complex Ru-2 prepared in Example 1.

[0057] Staphylococcus aureus was revived and cultured in TSB liquid medium at 37°C for 24 hours. The bacterial population density was determined by measuring the absorbance at a wavelength of 600 nm using an ELISA reader. After treatment with different concentrations and time, each group was cultured in an incubator at 37°C for 50 minutes. Subsequently, the diluted bacterial suspension was evenly spread on a TSB solid medium plate and cultured at 37°C for 15 hours. After the culture was completed, the number of bacterial colonies formed on the plate was counted and recorded.

[0058] The results are as follows Figure 3 As shown, Figure 3 The antibacterial effect of Ru-2 complex on Staphylococcus aureus after treatment at different concentrations and for different time periods is shown in Figure 2. Figure 3It can be seen that at a concentration of 4µg / mL, bacterial growth was inhibited, and the antibacterial effect increased with increasing concentration, and at a concentration of 8µg / mL, after 2h of treatment, the bacteria were basically dead. This shows that the Ru-2 complex has a good antibacterial effect. Example 6 This example provides an experiment of using the Ru-2 complex prepared in Example 1 in combination with polymyxin B to fight against Escherichia coli infection.

[0059] Mix 25µL of Ru-2, 25µL of polymyxin B, and 200µL of bacterial solution, and set the concentration gradient of the two drugs in a 96-well plate, one increasing along the X-axis and the other increasing along the Y-axis. Observe the growth of bacteria under different concentration combinations. Calculate the combined inhibition effect. By calculating the Fractional Inhibitory Concentration Index (FICI), determine whether the antibiotic combination has a synergistic effect (FICI < 0.5), additive effect (0.5 ≤ FICI ≤ 1), or antagonistic effect (FICI > 1). The results are shown in Figure 2. Figure 4 As shown, Figure 4 The Ru-2 complex is used in combination with polymyxin B to fight against Escherichia coli infection. Figure 4 It can be seen that the combination of Ru-2 complex and polymyxin B has a synergistic effect.

[0060] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes a preferred embodiment. Although the preferred embodiments of the present invention have been described, once those skilled in the art know the basic creative concept, they can make other changes and modifications to these embodiments, and these changes and modifications all fall within the scope of the present invention.

[0061] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A ruthenium polypyridine complex modified with benzenesulfonyl indole structure having the function of inhibiting bacterial toxins, characterized in that: It has a structure as shown in Formula I: Formula I; Wherein, in Formula I Has one of the following structures: 。 2. A method for preparing the benzenesulfonyl indole structure-modified ruthenium polypyridine complex according to claim 1, characterized in that: The following steps are involved: The main ligand as shown in formula a and the auxiliary ligand as shown in formula b are dissolved in a solvent, and a coordination substitution reaction is carried out under a protective atmosphere to introduce the main ligand into the auxiliary ligand to obtain a ruthenium polypyridine complex with a benzenesulfonyl indole structure as shown in formula I; Its synthetic route is as follows: ； Wherein, formula b and formula I Has one of the following structures: 。 3. The preparation method according to claim 2, characterized in that: The molar ratio of the main ligand to the auxiliary ligand is 1:0.8~1.

0.

4. The preparation method according to claim 2, characterized in that: The temperature of the coordination substitution reaction is 140° C. to 160° C., and the time is 7 h to 9 h.

5. The preparation method according to claim 2, characterized in that: The preparation method of the main ligand comprises the following steps: The compound shown in formula d and the compound shown in formula e are mixed, and a ketoaldehyde condensation reaction occurs under acid catalysis to form a main ligand containing benzenesulfonyl indole; Its synthetic route is as follows: 。 6. The preparation method according to claim 5, characterized in that: The molar ratio of the compound represented by formula d to the compound represented by formula e is 0.9-1.1:1.0-1.

2.

7. The preparation method according to claim 5, characterized in that: The temperature of the ketoaldehyde condensation reaction is 110° C. to 130° C., and the time is 3 h to 5 h.

8. Use of the ruthenium polypyridine complex with a benzenesulfonyl indole structure according to claim 1 in the preparation of an anti-Staphylococcus aureus product and / or a product for eradicating biofilm formed by Staphylococcus aureus.

9. Use of the ruthenium polypyridine complex with a benzenesulfonyl indole structure as claimed in claim 1 in combination with antibiotics in the preparation of an anti-Escherichia coli product.

10. The use according to claim 9, characterized in that: The antibiotic is polymyxin B.

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