Pharmaceutical composition based on iron-based complex and natural naphthoquinone and application thereof

Abstract

The invention discloses a pharmaceutical composition based on an iron-based complex and natural naphthoquinone. The pharmaceutical composition is formed by mixing a coordination polymer and a quinone compound, wherein the coordination polymer is obtained by coordinating epigallocatechin gallate and an iron element. According to the method, a coordination compound formed by natural polyphenol EGCG and Fe is combined with a quinone compound, a novel Fenton reaction system can be constructed, the system uses the quinone compound as a sustainable H2O2 supply source, H2O2 is continuously supplemented in a bacterial microenvironment through quinone redox cycle in an infected microenvironment, and the reaction time is shortened; according to the present invention, the bottleneck of insufficient H2O2 in the infected microenvironment is effectively overcome, the stable substrate is provided for the Fenton reaction, the Fenton reaction circulation is promoted by using the Fe < 3 + > reducing ability of the EGCG so as to produce Fe < 2 + >, and the synergistic interaction effect is generated between the EGCG and the Fe < 2 + > so as to achieve the continuous and efficient generation of OH, such that the removal ability on the salmonella and other drug-resistant bacteria is significantly enhanced;

Description

Technical Field

[0001] This invention relates to the field of antibacterial drug preparation technology, and to a pharmaceutical composition based on iron-based complexes and natural naphthoquinone, and its application in treating bacterial intestinal inflammation. Background Technology

[0002] Salmonella infection accounts for 70%-80% of bacterial foodborne illnesses in my country, causing tens of millions of infections annually. Salmonella infection is usually caused by contaminated water and food, with the bacterium invading the intestinal epithelium and triggering a severe inflammatory response. Currently, antibiotics are commonly used to treat Salmonella infections in China. However, the use of antibacterial drugs does not shorten the course of the disease; instead, it promotes the development of drug-resistant strains in the intestines, prolonging the shedding period and making treatment more difficult. The overuse of traditional antibiotics and their inevitable induction of drug resistance have led to a gradual increase in Salmonella resistance in recent years, with a broadening of the resistance spectrum. The development of drug resistance due to long-term antibiotic use poses a significant challenge to clinical prevention and treatment. The World Health Organization has listed it as a high-priority pathogen, necessitating the development of alternative antibacterial methods.

[0003] Chemokinetic therapy (CDT), proposed in recent years, relies on H2O2 at the site of infection. It utilizes the Fenton reaction, catalyzed by iron, to generate highly toxic hydroxyl radicals (•OH) from H2O2 for sterilization. In the Fenton reaction, the main catalytic component is Fe... 2+ It reacts with H2O2 to produce Fe. 3+ And hydroxyl radicals (•OH), and the generated Fe 3+ It can continue to react with H2O2 (the reaction is relatively slow) to produce Fe. 2+ And peroxide free radicals (•OOH), therefore, Fe 2+ A continuous supply of H2O2 and a stable H2O2 concentration are key to improving the efficiency of the Fenton reaction.

[0004] Researchers have discovered that Fe-based materials exhibit excellent catalytic activity in bacterial microenvironments due to their ability to form coordination networks with polyphenolic organic ligands. Polyphenols can enhance the catalytic activity of Fe... 3+ Reduced to Fe 2+ This improves the efficiency of the Fenton reaction. However, the initial endogenous H2O2 concentration in the bacterial microenvironment is low and unstable, even with Fe... 2+ The supply of H2O2 will stop the reaction after it is exhausted, making it difficult to continuously drive the generation of (•OH), which has become a key bottleneck restricting the application of CDT.

[0005] Juglone (JU), a natural quinone compound derived from walnuts, can generate H2O2 in the bacterial microenvironment through the quinone redox cycle. Specifically, in the presence of reducing agents (such as NADH / NADPH), it is first reduced to a semiquinone radical (SQ¯•) or hydroquinone (QH2), and then undergoes an oxidation reaction with oxygen to restore its quinone form. Simultaneously, it continuously generates ROS and releases H2O2 in situ via electron transport pathways. Therefore, combining phenol-iron coordination with quinone compounds can create drug compositions that simultaneously address the issues of insufficient H2O2 and the inability to supply iron catalysts in the bacterial microenvironment, meeting the practical need for efficient elimination of drug-resistant bacteria such as Salmonella. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a pharmaceutical composition based on iron-based complexes and natural naphthoquinone, and its application therein. This pharmaceutical composition can effectively overcome the Fe in the infection microenvironment. 2+ The bottleneck of insufficient H2O2 supply is addressed to improve the efficiency of the Fenton reaction and enhance the ability to eliminate bacteria.

[0007] To achieve this objective, the present invention adopts the following technical solution: A first aspect of the present invention is to provide a pharmaceutical composition based on an iron-based complex and natural naphthoquinone, said pharmaceutical composition being a mixture of a coordination polymer obtained by coordinating epigallocatechin gallate with iron and a quinone compound.

[0008] In one alternative embodiment, the concentration ratio of the coordination polymer to the quinone compound is 1:(0.8 to 1.2).

[0009] In one optional embodiment, the quinone compound is juglone, selaginella, vitamin K, or shikonin. Preferably, the quinone compound is juglone.

[0010] In one alternative embodiment, the concentration ratio of epigallocatechin gallate to iron in the coordination polymer is 1:(0.1-0.2).

[0011] In one optional embodiment, the coordination polymer is prepared by adding an iron-containing solution, ascorbic acid, and ethylenediaminetetraacetic acid to deionized water, stirring until homogeneous, and then adding epigallocatechin gallate solution dropwise for reaction. After the reaction is completed, the reaction solution is dialyzed, and the dialysate is filtered, purified, and lyophilized to obtain the coordination polymer nanoparticles of epigallocatechin gallate and iron.

[0012] In one alternative embodiment, the iron-containing solution: ascorbic acid: ethylenediaminetetraacetic acid = 0.027 mg / mL: 2 mg / mL: 1 mM.

[0013] In one alternative embodiment, the reaction time is 1 to 3 hours.

[0014] In one alternative embodiment, the dialysis conditions are: a molecular weight cutoff of 12,000–15,000 Da and a time of 48–96 h.

[0015] In one alternative embodiment, the filtration pore size is 0.1–0.3 μm; purification is performed using a dextran gel.

[0016] A second aspect of the present invention is to provide the use of a pharmaceutical composition based on an iron-based complex and natural naphthoquinone in the preparation of a medicament for treating Salmonella infection.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention constructs a novel Fenton reaction system by combining a coordination compound formed by the natural polyphenol EGCG and Fe with quinone compounds. This composition utilizes quinone compounds as an H2O2 supply source, continuously replenishing H2O2 in the bacterial microenvironment through a quinone redox cycle. This effectively overcomes the bottleneck of insufficient H2O2 in the infection microenvironment, providing a stable substrate for the Fenton reaction. Simultaneously, it leverages EGCG to coordinate with Fe... 3+ The reducing power promotes the Fenton reaction cycle, producing Fe 2+ The two work together to produce a synergistic effect, achieving continuous and efficient generation of (•OH), thereby significantly enhancing the ability to eliminate drug-resistant bacteria such as Salmonella. Attached Figure Description

[0018] Figure 1 This is a transmission electron microscope image of the pharmaceutical composition JU+ICP in Example 1 of the present invention.

[0019] Figure 2 This is a particle size diagram of the pharmaceutical composition JU+ICP in Example 1 of the present invention.

[0020] Figure 3 This is the UV-Vis spectrum of the pharmaceutical composition JU+ICP in Example 1 of the present invention.

[0021] Figure 4 This is the infrared spectrum of the pharmaceutical composition JU+ICP in Example 1 of the present invention.

[0022] Figure 5 This is the XPS spectrum of the pharmaceutical composition JU+ICP in Example 1 of the present invention.

[0023] Figure 6 The results of CDT performance testing of the pharmaceutical composition JU+ICP in Example 1 of this invention are shown.

[0024] Figure 7 This is a graph showing the effect of the pharmaceutical composition JU+ICP in Example 1 of the present invention on the growth curve of Salmonella Typhimurium.

[0025] Figure 8 The bacterial kill rate of the pharmaceutical composition JU+ICP against Salmonella typhimurium in Example 1 of this invention is shown.

[0026] Figure 9 The images show plate counts and live / dead staining images of the bacterial kill rate of the pharmaceutical composition JU+ICP against Salmonella typhimurium in Example 1 of this invention.

[0027] Figure 10 This is a scanning electron microscope image of Salmonella Typhimurium treated with the pharmaceutical composition JU+ICP in Example 1 of the present invention.

[0028] Figure 11 The results of the cytotoxicity assay of the pharmaceutical composition JU+ICP in Example 1 of this invention are shown.

[0029] Figure 12 Statistical results of Salmonella load in the cecum, spleen, and liver of mice.

[0030] Figure 13 The statistical results show the levels of serum inflammatory factors TNF-α, IL-6, IL-1β, and IL-10 in mice.

[0031] Figure 14 H&E slices of mouse colon, cecum, spleen, and liver. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0033] In the following examples, epigallocatechin gallate (EGCG) was purchased from Shanghai Yuanye Biotechnology Co., Ltd. (Shanghai, China), and ferric chloride and juglone were purchased from Maclean Biochemical Co., Ltd. (Shanghai, China).

[0034] Example 1 I. Synthesis of Epigallocatechin Gallate (EGCG) and Iron Coordination Polymer Nanoparticles 200 μL of FeCl3 solution (0.27 mg / mL) was added to 1 mL of nitrogen-saturated ultrapure water, followed by the addition of ascorbic acid (20 mg / mL, 10 μL) and EDTA (10 mM, 5 μL). After stirring in the dark for 30 min, 300 μL of EGCG solution (2 mg / mL) was added dropwise to the mixture and reacted for 1 h. Subsequently, the reaction solution was placed in a dialysis bag (Mw = 14000 Da) and dialyzed for 48 h to remove unreacted substances. The solution was then purified by extrusion through a 0.2 μm filter membrane and dextran gel G-100, and the purified solution was freeze-dried to obtain the coordination polymer nanoparticles EGCG-Fe of epigallocatechin gallate (EGCG) and iron, named ICP.

[0035] II. Characterization of coordination polymer nanoparticles EGCG-Fe (ICP) (I) Transmission Electron Microscopy (TEM) Characterization The prepared ICP was dissolved and dropped onto a copper grid. Excess moisture was absorbed by filter paper, and the nanoparticles were dried at room temperature. Morphological observation of the nanoparticles was performed using a transmission electron microscope, and the nanoparticles were diluted to an appropriate concentration and their particle size was measured using a laser particle size analyzer. The results are as follows: Figure 1 and Figure 2 As shown, from Figure 1 As can be seen from this, ICP has a monodisperse structure and exhibits a uniform spherical structure; from Figure 2 The results show that the particle size of ICP is approximately 5 nm, which preliminarily indicates that the ICP nanostructure has been successfully synthesized.

[0036] (II) Characterization by ultraviolet-visible spectroscopy and Fourier transform infrared spectroscopy (FTIR) The results are as follows: Figure 3 and Figure 4 As shown. From Figure 3 The UV-Vis spectrum shows that, due to the ligand-to-metal charge transfer (LMCT) effect, the EGCG-Fe complex (ICP) is red-shifted by 15 nm compared to free EGCG. Figure 4 As shown in the infrared spectrum, after ICP coordination, multiple phenolic hydroxyl groups of EGCG were deprotonated (3200-3500 cm⁻¹), and their OH stretching vibration peaks disappeared. However, uncoordinated hydroxyl groups may still exist, and due to enhanced hydrogen bonding or increased structural rigidity, the peaks broadened and merged into a single broad peak. Simultaneously, a significant Fe-O bond absorption peak appeared at 583 cm⁻¹, confirming the successful preparation of the ICP.

[0037] (iii) X-ray photoelectron spectroscopy (XPS) The results are as follows Figure 5 As shown. From Figure 5The XPS spectrum shows two strong binding energy peaks at 710 eV and 724 eV, respectively. According to the XPS standard binding energy table, the two strong binding energy peaks belong to Fe 2p3 / 2 and Fe 2p1 / 2, respectively, indicating that Fe exists in divalent form in ICP.

[0038] III. Preparation of pharmaceutical compositions consisting of coordination polymer nanoparticles (ICP) and juglone A mixed solution was prepared by dissolving coordination polymer nanoparticles (ICP) and juglone (JU) in deionized water. The concentration of coordination polymer nanoparticles in the prepared mixed solution was 150 μg / mL and the concentration of juglone was 160 μg / mL. The drug composition (ICP+JU) was obtained by stirring the mixed solution evenly.

[0039] Example 2 I. Synthesis of Epigallocatechin Gallate (EGCG) and Iron Coordination Polymer Nanoparticles 200 μL of FeCl3 solution (0.2 mg / mL) was added to 1 mL of nitrogen-saturated ultrapure water, followed by the addition of ascorbic acid (20 mg / mL, 10 μL) and EDTA (10 mM, 5 μL). After stirring in the dark for 30 min, 300 μL of EGCG solution (2 mg / mL) was added dropwise to the mixture and reacted for 2 h. Subsequently, the reaction solution was placed in a dialysis bag (Mw = 13000 Da) and dialyzed for 48 h to remove unreacted substances. The solution was then purified by extrusion through a 0.2 μm filter membrane and dextran gel G-100, and the purified solution was freeze-dried to obtain the coordination polymer nanoparticles of epigallocatechin gallate (EGCG) and iron.

[0040] II. Preparation of pharmaceutical compositions consisting of coordination polymer nanoparticles and juglone A mixed solution was prepared by dissolving coordination polymer nanoparticles and juglone in deionized water. The concentration of coordination polymer nanoparticles in the mixed solution was 150 μg / mL, and the concentration of juglone was 120 μg / mL. The drug composition was obtained by stirring the mixed solution evenly.

[0041] Example 3 I. Synthesis of Epigallocatechin Gallate (EGCG) and Iron Coordination Polymer Nanoparticles 200 μL of FeCl3 solution (0.4 mg / mL) was added to 1 mL of nitrogen-saturated ultrapure water, followed by the addition of ascorbic acid (20 mg / mL, 10 μL) and EDTA (10 mM, 5 μL). After stirring in the dark for 30 min, 300 μL of EGCG solution (2 mg / mL) was added dropwise to the mixture and reacted for 1 h. Subsequently, the reaction solution was placed in a dialysis bag (Mw = 15000 Da) and dialyzed for 48 h to remove unreacted substances. The solution was then purified by extrusion through a 0.2 μm filter membrane and dextran gel G-100, and the purified solution was freeze-dried to obtain the coordination polymer nanoparticles of epigallocatechin gallate (EGCG) and iron.

[0042] II. Preparation of pharmaceutical compositions consisting of coordination polymer nanoparticles and juglone A mixed solution was prepared by dissolving coordination polymer nanoparticles and juglone in deionized water. The concentration of coordination polymer nanoparticles in the mixed solution was 150 μg / mL, and the concentration of juglone was 180 μg / mL. The drug composition was obtained by stirring the mixed solution evenly.

[0043] Test case

[0044] I. Validation of the chemical kinetics (CDT) performance of JU+ICP

[0045] The CDT performance of ICP was evaluated using a classic MB degradation assay. As a •OH scavenger, MB can be degraded by •OH, therefore, measuring the amount of MB degradation can qualitatively detect the generation of •OH.

[0046] The coordination polymer nanoparticles (ICP) from Example 1 were dissolved in deionized water to prepare an aqueous solution. The prepared aqueous solution and the pharmaceutical composition (ICP+JU) prepared in Example 1 were then mixed thoroughly with methylene blue (MB) and hydrogen peroxide (H2O2) to obtain two mixed solutions: the ICP+MB+H2O2 group and the ICP+JU+MB+H2O2 group. An MB+H2O2 control group was also included. The final concentrations of ICP, JU, MB, and H2O2 in each mixed solution were 150 μg / mL, 160 μg / mL, 15 μg / mL, and 1 mM, respectively. Subsequently, the three mixed solutions were placed in a 37°C constant temperature shaking incubator for 0, 15, 30, 60, and 120 min, respectively, and the OD 665 nm of the solutions at each time point was measured using a UV spectrophotometer. The results are as follows: Figure 6 As shown.

[0047] from Figure 6As can be seen, after MB and H2O2 were mixed evenly and incubated for different times, the absorbance of MB at 665 nm remained stable, indicating that the concentration of MB did not change and no •OH was generated under these conditions. However, after incubation with ICP for 15, 30, 60, and 120 min, the absorbance of MB at 665 nm gradually decreased, and 75.96% of MB was degraded at 120 min. In the presence of juglone (JU), MB was further degraded to 85.90% at 120 min, indicating that ICP has excellent Fenton reaction properties, effectively catalyzing the production of highly toxic •OH from H2O2, thus exhibiting CDT performance. Furthermore, the presence of juglone further promotes the enhancement of the Fenton reaction.

[0048] II. In vitro antibacterial activity of JU+ICP (a) Bacterial growth curve To investigate the anti-Salmonella activity of the pharmaceutical composition (JU+ICP) of Example 1, its effect on the growth of Salmonella was determined.

[0049] The overnight cultured *Salmonella typhimurium* ATCC 14028 bacterial suspension was adjusted to 0.5 McFarland turbidity standard, then diluted 1:100 in MH broth (MHB) medium, washed three times with sterile PBS, and resuspended (8000 r / min, 5 min). JU solution (160 μg / mL), ICP+H2O2 solution (ICP: 150 μg / mL; H2O2: 1 mM), and JU+ICP+H2O2 solution (JU: 160 μg / mL; ICP: 150 μg / mL; H2O2: 1 mM) were prepared, and each solution was aliquoted with the bacterial suspension (MHB 1:100 dilution) into 96-well microplates. After sealing the wells with a breathable sealing membrane, the plates were incubated at 37°C. The growth curve was monitored for 24 h using the continuous kinetic mode of a TecanInfinite M200 microplate reader, with absorbance values ​​read at 600 nm every hour. Results are as follows: Figure 7 As shown. From Figure 7 As can be seen from the comparison of the effects of each group, the JU+ICP group showed a more superior growth inhibitory effect on Salmonella.

[0050] (ii) Bacterial survival rate To evaluate the bactericidal effect of the pharmaceutical composition (JU+ICP) in Example 1, bacterial counting was performed. The overnight cultured *Salmonella typhimurium* ATCC 14028 suspension was adjusted to 0.5 McFarland turbidity standard and then diluted 1:100 in MH broth (MHB). The suspension was washed three times with sterile PBS and resuspended (8000 r / min, 5 min). The test system (JU, ICP+H2O2, and JU+ICP+H2O2 solutions (concentrations as above)) was added to the bacterial suspension and incubated for 24 h. Samples were diluted appropriately and spread 100 μL onto MHA solid medium and incubated at 37°C for 24 h for colony counting. The effect of each treatment group on bacterial viability was qualitatively assessed by double staining ATCC 14028 with the LIVE / DEAD BacLight™ Bacterial Viability kit. The effect on bacterial morphology after treatment was observed by scanning electron microscopy. The results are shown below. Figure 8 , 9 As shown in Figures 1 and 10. Among them, Figure 8 The bacterial kill rate of different treatment groups against Salmonella typhimurium; Figure 9 Plate counts and live / dead staining images of the bacterial kill rate of Salmonella Typhimurium in different treatment groups; Figure 10 Scanning electron microscope images of Salmonella typhimurium from different treatment groups.

[0051] Figure 8 and Figure 9 The results showed that the ICP group effectively inhibited the growth of Salmonella. However, JU+ICP exhibited a stronger Salmonella eradication effect, reducing ATCC 14028 colonies by 42.47±0.14% compared to the ICP group, indicating that its antibacterial effect was superior to the single-drug group. Similarly, the live / dead bacteria staining test (SYTO 9 / PI) results showed that the bacteria (green) and dead bacteria (red) in the JU+ICP group were effectively fused, confirming its excellent bactericidal performance.

[0052] Figure 10 The results showed that the Salmonella treated with JU had a more intact morphological structure, while the JU+ICP nanoparticle treatment group showed significant structural depression and distortion.

[0053] III. Cytotoxicity Verification The toxicity of the pharmaceutical composition (JU+ICP) of Example 1 to the model cell line RAW 264.7 was evaluated using the CCK8 assay. Serial concentrations of the system solution were prepared using sterile PBS. RAW 264.7 cells were seeded in 96-well plates and the cell density was adjusted to 5 × 10⁶ cells / well. 4Cells were cultured at 37°C for 12 h in a 5% CO2 incubator. Then, 100 μL of JU+ICP at various concentrations (final concentrations of 0.2, 0.4, 0.8, and 1 mg / mL, quantified by JU) were added to each well. A control group (10% FBS DMEM medium + cells) and a blank group (10% FBS DMEM medium) were also included. After a second incubation at 37°C with 5% CO2 for 24 h, 100 μL of 10% CCK8 medium was added to each well for 1 h of incubation. The absorbance was measured at 450 nm using a microplate reader. The cytotoxicity of the drug was evaluated based on the cell viability (CV%). Each group was repeated six times.

[0054]

[0055] Where As is the absorbance of the sample group; Ab is the absorbance of the blank group; and Ac is the absorbance of the control group.

[0056] The cytotoxicity of the drug was evaluated based on the obtained cell viability (CV%). Each group was tested in six replicates, and the average value was taken. Results are as follows: Figure 11 As shown.

[0057] Figure 11 The results showed that JU+ICP had no significant effect on cell viability. When its concentration reached 1 mg / mL (quantified by JU), the cell viability remained above 90%, which fully demonstrates that JU+ICP has good cell compatibility.

[0058] IV. In vivo antibacterial activity of JU+ICP To investigate the in vivo antibacterial activity of the pharmaceutical composition (JU+ICP) in Example 1, an in vivo acute intestinal infection model of Salmonella typhimurium was established for testing.

[0059] A gastrointestinal infection model was established using 6-week-old female C57BL / 6J mice. After one week of environmental acclimatization, streptomycin (200 mg / mL, 100 μL) was administered by gavage to disrupt the intestinal flora. 24 hours later, streptomycin was administered at a dose of 1.5 × 10⁻⁶ μL. 7 CFU of Salmonella Typhimurium ATCC14028 was administered orally. Infected mice were randomly divided into 5 groups (n=8 / group): (i) PBS control group, (ii) juglone monotherapy group (JU, 64 mg / kg), (iii) iron complex group (ICP, 60 mg / kg), and (iv) JU+ICP mixed group (64 mg / kg JU + 60 mg / kg ICP). Mice were sacrificed 5 days after administration for organ analysis. Intestines, liver, and spleen were harvested, homogenized in sterile PBS, and quantitatively cultured to calculate CFU. The results are as follows: Figure 12The AC plot is shown. Further analysis of serum inflammatory factor levels yielded the following results: Figure 13 The AD diagram is shown. Samples were fixed in 4% paraformaldehyde, embedded in paraffin, and sectioned (5 μm) for hematoxylin-eosin (H&E) staining and analysis. The results are as follows. Figure 14 The AD diagram is shown below.

[0060] from Figure 12 As shown in A, the bacterial load was lowest in the JU+ICP group on day 5 post-infection, at approximately 7.69 log₂O₅. 10 CFU / g, an improvement of 1.98 log compared to the ICP group. 10 CFU / g has bactericidal efficacy and outstanding antibacterial effect.

[0061] from Figure 12 B and Figure 12 As shown in C, on the 5th day after infection, in terms of systemic infection indicators, the bacterial load in the spleen of the JU+ICP group decreased by about one order of magnitude compared with the ICP group, and the bacterial load in the liver decreased by about 1.2 orders of magnitude compared with the ICP group.

[0062] from Figure 13 The AD study showed that on day 5 post-infection, the levels of pro-inflammatory factors TNF-α, IL-6, and IL-1β in the JU+ICP group decreased by 13.53±0.54%, 25.21±0.74%, and 30.83±2.61%, respectively, compared to the ICP group, while the level of anti-inflammatory factor IL-10 increased by 15.31±1.18%. This indicates that the JU+ICP treatment can significantly inhibit the inflammatory cascade response.

[0063] from Figure 14 As shown in AB, the intestinal tissue of mice in the S.Tm infection group showed coagulative necrosis, a large number of bacterial fragments, and decellularized structures; the JU group showed varying degrees of goblet cell and villus loss, and unclear epithelial structure; the intestinal structure of the JU+ICP treatment group was relatively clear.

[0064] from Figure 14 CD analysis revealed that the livers of S. tm-infected mice and the JU group exhibited significant fibrosis and swelling, accompanied by extensive hepatic cord necrosis, inflammatory foci, neutrophil infiltration, and widespread fatty degeneration; the spleen was enlarged, with necrotic foci, central atrophy, and infiltration of erythrocytes and neutrophils. The ICP group showed localized necrosis and congestion in both the liver and spleen. In contrast, the inflammatory infiltration was significantly reduced in the JU+ICP treatment group. These data indicate that the JU+ICP group provides systemic protection against S. tm-infected mice.

[0065] The applicant declares that the technical solution of this invention is illustrated by the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

[0066] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0067] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A pharmaceutical composition based on an iron-based complex and natural naphthoquinone, characterized in that, The pharmaceutical composition is a mixture of a coordination polymer obtained by coordinating epigallocatechin gallate with iron and a quinone compound.

2. The pharmaceutical composition based on iron-based complexes and natural naphthoquinone according to claim 1, characterized in that, The concentration ratio of the coordination polymer to the quinone compound is 1:(0.8 to 1.2).

3. The pharmaceutical composition based on iron-based complexes and natural naphthoquinone according to claim 1, characterized in that, The quinone compounds are juglone, sucralose, vitamin K, or shikonin.

4. The pharmaceutical composition based on iron-based complexes and natural naphthoquinone according to claim 1, characterized in that, In the coordination polymer, the concentration ratio of epigallocatechin gallate to iron is 1:(0.1-0.2).

5. The pharmaceutical composition based on iron-based complexes and natural naphthoquinone according to claim 1, characterized in that, The preparation method of the coordination polymer is as follows: iron-containing solution, ascorbic acid and ethylenediaminetetraacetic acid are added to deionized water, stirred evenly, and then epigallocatechin gallate solution is added dropwise for reaction. After the reaction is completed, the reaction solution is dialyzed. After filtration, purification and freeze-drying, the coordination polymer nanoparticles of epigallocatechin gallate and iron are obtained.

6. The pharmaceutical composition based on iron-based complexes and natural naphthoquinone according to claim 5, characterized in that, Iron-containing solution: ascorbic acid: ethylenediaminetetraacetic acid = 0.027 mg / mL: 2 mg / mL: 1 mM.

7. The pharmaceutical composition based on iron-based complexes and natural naphthoquinone according to claim 5, characterized in that, The reaction time is 1 to 3 hours.

8. The pharmaceutical composition based on iron-based complexes and natural naphthoquinone according to claim 5, characterized in that, The dialysis conditions were: molecular weight cutoff of 12,000–15,000 Da, and time of 48–96 h.

9. The pharmaceutical composition based on iron-based complexes and natural naphthoquinone according to claim 5, characterized in that, The filtration pore size was 0.1–0.3 μm; purification was performed using dextran gel.

10. The use of the pharmaceutical composition of claim 1, based on an iron-based complex and natural naphthoquinone, in the preparation of a medicament for treating Salmonella infection.

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