Natural product co-assembled nanoparticles as well as preparation method and application thereof

Abstract

The invention discloses a preparation method of natural product co-assembled nanoparticles, and hesperidin and emodin are subjected to a co-assembly process to form carrier-free nanoparticles, so that the natural product co-assembled nanoparticles are obtained. The invention further provides the natural product co-assembled nanoparticles prepared by the preparation method and application of the natural product co-assembled nanoparticles. According to the natural product co-assembled nanoparticles provided by the invention, emodin which is rapidly released in an early stage can rapidly kill methicillin-resistant staphylococcus aureus (MRSA) on the surface of a wound, and a local antibacterial barrier is established; the hesperidin continuously released in the later stage plays an anti-inflammatory role by regulating and controlling the expression of inflammatory factors, and promotes the proliferation of fibroblasts and the secretion of angiogenesis-related growth factors (such as VEGF) at the same time. The'space-time synergistic release strategy 'provides a multifunctional platform integrating antibiosis, anti-inflammation and tissue repair for chronic wound treatment, and is suitable for accelerating healing of chronic wounds such as infection, diabetes and burn.

Description

Technical Field

[0001] The present application relates to the field of nanomedicine technology, and in particular to natural product co-assembled nanoparticles and a preparation method and application thereof. Background Art

[0002] Hesperidin (HSD) is a natural active flavonoid component widely found in citrus fruits and has multiple biological activities.

[0003] The specific effects of hesperidin in the field of wound repair include: (1) Anti-inflammatory activity: It can inhibit the production and release of inflammatory mediators, reduce tissue edema, alleviate wound inflammation, and accelerate the wound healing process. (2) Antioxidant activity: It can scavenge free radicals, slow down oxidative damage to cells, maintain the normal function and activity of cells around the wound, protect wound tissue from free radical damage, and create a favorable environment for wound healing. (3) It can stimulate cell proliferation and migration, fill wound defects, form new skin tissue, and accelerate the re-epithelialization process of the wound. (4) It stimulates the synthesis of collagen, which is a key component in the wound healing process and helps accelerate wound healing.

[0004] However, hesperidin's medical applications are greatly limited due to its poor solubility in water and common fat-soluble solvents. To improve the solubility and bioavailability of hesperidin, researchers have had to resort to complex chemical modifications or special formulation techniques, which undoubtedly increases the cost and difficulty of preparation. Hesperidin is prone to degradation or denaturation under adverse conditions such as light, high temperature, and high humidity, which not only impairs its stability but also reduces its efficacy. In addition, hesperidin has limited permeability, making it difficult to penetrate deep into wounds, thus affecting its therapeutic effect.

[0005] Emodin (EMO) is a natural anthraquinone compound widely found in many plants, especially in Polygonaceae plants such as Rheum palmatum L. In addition, the dried rhizomes and roots of Polygonum cuspidatum, the roots of Rumex dentatus L. and R. crispus L. of Cantonese plants, and the fresh seeds of Cassia tora L. of Leguminosae plant also contain emodin.

[0006] The specific effects of emodin in the field of wound repair include: (1) Antibacterial effect: It has significant antibacterial activity and can effectively inhibit the growth of a variety of bacteria, including but not limited to common pathogens such as Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. It helps to reduce the risk of wound infection and create a good microenvironment for wound repair. (2) Anti-inflammatory effect: It can inhibit the release of inflammatory factors such as TNF-α and IL-6, thereby reducing the inflammatory response of the wound and promoting wound healing. (3) Promoting wound healing: By promoting the formation of granulation tissue and epidermal proliferation in the wound, it significantly accelerates the healing speed of the wound. In addition, it can also regulate the synthesis and release of cytokines such as transforming growth factor (TGF-β1) in the wound, as well as regulate the level of Smads protein in the TGF-β1 signal transduction pathway, thereby upregulating the level of cytokines in the wound healing process and further improving the speed and quality of wound healing. (4) Inhibit scar formation: Excessive secretion of TGF-β1 leads to excessive deposition of collagen (such as type I collagen encoded by COLIA1) and extracellular matrix proteins, which in turn triggers the formation of hypertrophic scars and exacerbates the degree of fibrosis. In the middle and late stages of wound healing, emodin can inhibit macrophage M2 polarization, thereby reducing the secretion of TGF-β1, further affecting the expression levels of molecules such as TGF-β1, α-smooth muscle actin and COLIA1, reducing the degree of wound fibrosis, thereby effectively reducing the formation of scars and inhibiting the formation of hypertrophic scars. Emodin is of great significance for the repair of wounds that may cause scar formation, such as burns and trauma.

[0007] However, emodin is toxic and highly irritating. Excessive use can trigger an excessive immune response in the skin, leading to symptoms such as redness, itching, and stinging. For those with sensitive skin, it can also trigger allergic reactions such as allergic purpura, drug eruptions, and dermatitis, exacerbating skin discomfort. Furthermore, emodin also suffers from low solubility, poor stability, and low bioavailability. Therefore, further research is needed to overcome these shortcomings and improve the effectiveness of emodin in wound repair.

[0008] In summary, in order to improve the solubility and bioavailability of hesperidin and emodin, researchers have to adopt complex chemical modification methods or use special formulation technologies, which undoubtedly increases the preparation cost and difficulty, and also sets a high threshold for their large-scale application. Summary of the Invention

[0009] To address the above technical issues, the first objective of the present invention is to provide a method for preparing natural product co-assembled nanoparticles; the second objective is to provide natural product co-assembled nanoparticles produced by the above preparation method; and the third objective is to provide applications of the above natural product co-assembled nanoparticles. The natural product co-assembled nanoparticles provided in this application achieve precise delivery of emodin and hesperidin through a "temporal and spatial coordinated release strategy," significantly improving the healing effect of chronic wounds.

[0010] The technical solutions provided by the present invention are as follows: A method for preparing natural product co-assembled nanoparticles comprises forming hesperidin and emodin into nanoparticles through a co-assembly process.

[0011] Preferably, the method comprises the following steps: adding a mixed solution of hesperidin and emodin dropwise into a polyvinyl alcohol aqueous solution, shaking and mixing, ultrasonicating, centrifuging, and collecting the precipitate to obtain the product.

[0012] Preferably, the mixed solution of hesperidin and emodin is prepared by the following method: Prepare a hesperidin dimethyl sulfoxide solution with a concentration of 2.5-80 mM; Prepare a 2.5-80 mM emodin dimethyl sulfoxide solution; Then mix well and you have it.

[0013] Preferably, the mass percentage concentration of the polyvinyl alcohol aqueous solution is 0.1-1.0%; The mixed solution was added dropwise to the polyvinyl alcohol aqueous solution at a rate of 1 drop per second.

[0014] Preferably, the ultrasonication time is 2-5 min, the ultrasonication power is 15-40 kHz, and the ultrasonication temperature is 25-30° C. The centrifugation time is 20-40 minutes, and the centrifugal speed is 12000-14000 rpm.

[0015] Preferably, the volume ratio of the mixed solution of hesperidin and emodin to the polyvinyl alcohol aqueous solution is 1:(8-10).

[0016] Preferably, the molar ratio of emodin to hesperidin is 4:1-1:8.

[0017] Natural product co-assembled nanoparticles prepared by any of the preparation methods described above.

[0018] The application of the above-mentioned natural product co-assembled nanoparticles in the preparation of drugs for treating antibacterial, anti-inflammatory, promoting wound healing and inhibiting scar formation.

[0019] Natural product co-assembly nanotechnology is a technology that allows natural product molecules to spontaneously assemble into nanoscale structures or particles through non-covalent interactions (such as hydrophobic interactions, hydrogen bonds, π-π stacking, etc.) without the need for external carriers.

[0020] The natural product co-assembled nanoparticles provided herein are obtained by co-assembling hesperidin and emodin to form nanoparticles. These natural product co-assembled nanoparticles are a carrier-free, chemical crosslinker-free, pure drug nanodelivery system. This system achieves self-assembly through weak interactions (such as hydrogen bonding and π-π stacking) between hesperidin and emodin molecules, completely eliminating traditional carrier materials and spontaneously forming nanoparticles. This significantly simplifies the process and reduces costs and environmental risks. Furthermore, the nanostructure exhibits enhanced biocompatibility and active ingredient retention, improving the solubility and stability of the natural product and enhancing its in vivo bioavailability. The nanostructure helps drug molecules penetrate tissue barriers and better bind to receptors in the body, enhancing their pharmacological activity. Furthermore, the natural product co-assembled nanoparticles possess a stable nanostructure and hydrophilicity, which helps maintain drug activity, resulting in higher targeting and bioavailability, allowing for reduced dosage. MTT assays and pathological sections of major animal organs (heart, liver, spleen, lungs, and kidneys) have demonstrated that co-assembly reduces the risk of immune and toxic reactions, thereby reducing potential side effects.

[0021] The co-assembled nanoparticles provided in this application address the problems of low solubility, poor stability, and low bioavailability of hesperidin and emodin. Due to their small size and unique physicochemical properties, the nanoparticles can more easily penetrate tissue barriers and act directly on the wound surface, achieving targeted release and efficient utilization of the drug. Furthermore, the two active ingredients used in this application exhibit a "temporal and spatial synergistic release strategy": first, the rapid release of emodin controls infection, while the sustained release of hesperidin reduces inflammation and promotes healing, achieving a cascade therapeutic effect that meets the multi-stage infection-inflammation-healing needs of chronic wounds. The nanoparticles are suitable for chronic wounds such as those caused by infection, diabetes, and burns. This temporal and spatial synergistic release strategy significantly accelerates the healing process of chronic wounds.

[0022] The co-assembled nanoparticles provided in this application eliminate the need for existing carrier materials such as liposomes and polymers. Instead, they achieve efficient delivery of plant active ingredients (emodin and hesperidin) through molecular self-assembly and a spatiotemporal coordinated release strategy. The emodin and hesperidin used are less susceptible to developing drug resistance than traditional antibiotics and possess comprehensive wound-healing benefits beyond simple antibacterial or anti-inflammatory properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 The preparation and characterization of hesperidin-emodin co-assembled nanoparticles in the embodiment of the present invention; (A) Tyndall effect of nanoparticle solution; (B) Molecular simulation; (C) Stability of nanoparticles at room temperature (25°C); (D) Stability of nanoparticles at 4°C; (E) TEM image; (F) Size distribution of nanoparticles; (G) Potential distribution of nanoparticles; (H) XRD pattern; (I) FT-IR spectrum; Figure 2 The release behavior of hesperidin-emodin co-assembled nanoparticles in the embodiment of the present invention; (A) the curve of emodin release from the co-assembled nanoparticles; (B) the curve of hesperidin release from the co-assembled nanoparticles; Figure 3 The antibacterial activity results of hesperidin-emodin co-assembled nanoparticles in the examples of the present invention are as follows; (A) Inhibition zone; (B) MIC of emodin; (C) MIC of hesperidin-emodin co-assembled nanoparticles; (D) Colony formation of hesperidin-emodin co-assembled nanoparticles; (E) Destructive effects of different drugs on MRSA biofilm; (F) Quantification of crystal violet in biofilms; Figure 4 This is the biocompatibility result of hesperidin-emodin co-assembled nanoparticles in the embodiment of the present invention; (A) Toxicity to endothelial cells; (B) Toxicity to fibroblasts; (C) Hemolysis test; (D) Morphological changes of red blood cells; Figure 5 The anti-inflammatory activity results of hesperidin-emodin co-assembled nanoparticles in the examples of the present invention; (A) TNF-α expression level; (B) IL-6 expression level; (C) IL-1β expression level; (D) IL-10 expression level Figure 6 The in vitro healing ability of hesperidin-emodin co-assembled nanoparticles in the examples of the present invention; (A) cell scratch test; (B) in vitro tube formation test; Figure 7 This is the therapeutic effect of MRSA-infected mouse wounds in the embodiment of the present invention; (A) Photos of wounds after 2, 4, 6, 7, and 10 days of treatment; (B) Schematic diagrams of the corresponding simulations after 2, 4, 6, 7, and 10 days of wound treatment; (C) Wound healing rates of the corresponding mice; (D) Bacterial counts in wounds after 4 days of treatment; (E) Bacterial survival rates in wounds after 4 days of treatment; (F) Weight changes of mice during treatment; Figure 8 Pathological observation and immunohistochemistry results of skin tissue in the examples of the present invention; (A) H&E staining; (B) Masson staining; (C) VEGF immunohistochemistry; (D) CD31 immunohistochemistry; Figure 9 The results of in vivo biosafety experiments in the examples of the present invention are as follows; (AD) Blood tests of white blood cells (WBC), red blood cells (RBC), hemoglobin (HGB), and platelets (PLT); (E) H&E staining results of the heart, liver, lung, spleen, and kidney of mice on day 12 after different treatments. DETAILED DESCRIPTION

[0025] In order to help those skilled in the art better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of this application.

[0026] Material synthesis: 100 μL of a mixture of hesperidin and emodin of different concentrations was added dropwise to 900 μL of 0.5% polyvinyl alcohol aqueous solution at 1 drop / s, shaken to mix, and ultrasonicated for 5 min at an ultrasonic power of 20 kHz and a temperature of 25-30°C. The mixture was then centrifuged at 14,000 rpm for 30 min, the precipitate was collected, and resuspended in ddH2O.

[0027] The following experiments were performed using the co-assembled nanoparticles: (1) Characterization analysis Emodin and hesperidin have no Tyndall effect in DMSO, but they show Tyndall effect after self-assembly into nanoparticles ( Figure 1 A), confirming the formation of nanostructures. Molecular dynamics simulation ( Figure 1B) The results showed that hesperidin and hesperidin molecules self-assembled through hydrogen bonding and π-π stacking to form the core of the nanoparticles. Rhein and rhein molecules were wrapped in the outer layer in the form of J-type aggregates through π-π stacking, and formed interfacial interactions with hesperidin molecules through hydrogen bonding, ultimately forming a core-shell structure with a clear orientation. Moreover, after storing the co-assembled nanoparticles in aqueous solution at room temperature (25°C) for 3 days and in a refrigerator at 4°C for 7 days, there was no precipitation and the particle size remained basically unchanged. Figure 1 C, D), confirming that HE NPs have excellent colloidal stability. TEM ( Figure 1 E) Observation showed that HE NPs exhibited spindle-shaped nanostructures, and dynamic light scattering (DLS, Figure 1 F, G) showed that the average particle size was 335 nm (PDI = 0.29) and the Zeta potential was -13.1 mV, indicating that the nanoparticles had a negative surface charge and a uniform particle size distribution. After HSD and EMO were simply mechanically mixed, their XRD ( Figure 1 H) includes the crystal diffraction peaks of HSD and EMO. Compared with the physical mixture, the crystallization peaks in the self-assembled hesperidin-emodin co-assembled nanoparticles (HE NPs) are greatly reduced, indicating that HSD and EMO have been redirected to HE molecules to a certain extent, confirming the formation of nanoformulation HE NPs. When HSD and EMO self-assemble into nanoparticles, FT-IR spectrum ( Figure 1 I) Significant changes: 3300cm -1 The absorption peak near (OH) becomes broader, indicating that the hydrogen bonding effect of HE is enhanced and a more complex hydrogen bonding network is formed; 2938, 2917 cm -1 The (CH) peak is enhanced, indicating that the hydrophobic effect is enhanced, resulting in an increase in the intensity of the CH stretching vibration peak; 1665cm -1 (C=O) and 1600-1440cm -1 900-690cm -1 The characteristic peak of the benzene ring is caused by the π-π stacking affecting the vibration mode of the ketophenyl ring, resulting in peak shift and intensity changes. In addition, the co-assembly process leads to the addition of a new peak at 2746 cm due to interaction or conformational changes. -1 and 2646cm -1 The above characterization analysis proved that hesperidin and emodin were successfully co-assembled into spindle-shaped nanoparticles.

[0028] (2) Assembly rate and release experiments After centrifugation, the supernatant was collected and the contents of hesperidin and emodin were measured by HPLC and UV spectroscopy, respectively, and the assembly rates of hesperidin and emodin in the precipitate (i.e., nanoparticles) were calculated.

[0029] (Dosage - drug content in supernatant) / dosage * 100% The results showed that the assembly rates of emodin and hesperidin in the self-assembled nanoparticles with a molar ratio of 4:1 were 70% and 99%, respectively.

[0030] The co-assembled HE NPs were resuspended in phosphate buffered saline (PBS) at pH 5.4, 7.2, and 8.5, and their in vitro release behavior was investigated at 37°C. The results showed that the nanoparticles exhibited a pH-dependent release profile, with the slowest release rate in acidic environments and the fastest release rate in alkaline environments. This is primarily due to enhanced π-π stacking and hydrogen bonding in acidic environments, which slows drug release. In contrast, in alkaline environments, weakened π-π stacking and hydrogen bonding reduce nanoparticle stability, accelerating drug release.

[0031] result( Figure 2 ) showed that in an acidic environment, the release rate of emodin was 11.15% in 1 hour and reached 24.79% in 24 hours; however, hesperidin release was delayed, with a release rate of 8.83% in 2 hours and 37.11% in 24 hours. Under physiological conditions, the release rate of emodin was 28.72% in 1 hour and 77.47% in 24 hours; hesperidin release was also delayed, with a release rate of 19.64% in 2 hours and 99.27% in 24 hours. Notably, in an alkaline environment, the release behavior of emodin and hesperidin changed significantly: at 1 hour, the release rates of emodin and hesperidin were 7.70% and 26.18%, respectively. Hesperidin was completely released (100%) within 6 hours, while the release rate of emodin reached 95.89% after 24 hours.

[0032] Further analysis revealed that hesperidin exhibits delayed release in both acidic and neutral environments, but its later release rate exceeds that of emodin. This is primarily due to the delayed release of hesperidin due to the initial strong hydrogen bonds within the core, which must break through the "barrier" formed by the outer layer of emodin. However, over time, these hydrogen bonds may break due to hydration or molecular thermal motion, leading to a decrease in the core's stability and accelerated release. Furthermore, the three-dimensional π-π stacking of hesperidin's core faces a higher energy barrier, while the π-π stacking of emodin's outer layer is more easily broken in one dimension (e.g., the chain-like structure of J-shaped aggregates). After the initial release, the release rate of the remaining molecules may be slowed due to less steric hindrance or solubility limitations. In alkaline environments, emodin, as a component of the outer layer, experiences the first disruption of its π-π stacking, leading to rapid disintegration of the outer layer, resulting in rapid release. Hesperidin, however, resides in the core, and the outer layer dissociates, exposing it directly to the alkaline medium. Under alkaline conditions, the phenolic hydroxyl groups in its molecules deprotonate to form negative ions, significantly increasing its water solubility and promoting the collapse of the core structure, allowing the molecules to dissolve and diffuse rapidly. In contrast, emodin, an anthraquinone compound, has a solubility that is less affected by pH. Its release rate is later limited by the "buffer layer" formed by the hydrophobic interactions of J-type aggregates, resulting in a gradual slowing of its release rate.

[0033] The differentiated release behavior of HE NPs is the result of the combined effects of intermolecular interactions, pH responsiveness, and nanostructure, resulting in a unique "fast-slow sequential release" pattern. This time-programmed release characteristic is more conducive to HE NPs exerting their biological functions: early on, emodin can be rapidly released to establish a local antibacterial barrier and effectively kill MRSA; later, hesperidin is continuously released in large quantities, accelerating wound healing through anti-inflammatory effects and promoting fibroblast proliferation and new angiogenesis. Therefore, this release characteristic provides a multifunctional platform for the treatment of chronic wounds that integrates antibacterial, anti-inflammatory, and tissue repair. It can not only quickly control the disease in the early stages of infection, but also maintain effective concentrations for a long time, significantly improving the treatment effect on MRSA-infected wounds while taking into account safety and drug resistance prevention and control.

[0034] (3) Antibacterial test like Figure 3 As shown, the antibacterial efficacy of the nanoparticles against MRSA was tested using inhibition zone, MIC, and dilution plating assays. The results showed that hesperidin had no antibacterial activity (no obvious inhibition zone), while emodin had good antibacterial activity, with an MIC of approximately 10 μg / mL. The nanoparticles co-assembled with hesperidin retained the antibacterial activity of emodin, with an antibacterial rate exceeding 80%. Furthermore, HE NPs were able to effectively eliminate 65% of biofilms, overcoming bacterial resistance.

[0035] (4) Pharmacological efficacy experiments at the cellular level like Figure 4 As shown, the toxicity of the drugs to fibroblasts and endothelial cells was tested using the MTT assay. The results showed that hesperidin was safe and non-toxic, but emodin was toxic to endothelial cells at concentrations of 40 and 50 μg / mL. However, after co-assembly with hesperidin, its toxicity was significantly improved. Hemolysis tests demonstrated its blood compatibility.

[0036] like Figure 5 As shown, the ELISA test results showed that after the drug was co-cultured with macrophages, HE NPs could effectively inhibit the expression of pro-inflammatory factors and promote the expression of anti-inflammatory factors, indicating that HE NPs have good anti-inflammatory activity.

[0037] like Figure 6 As shown in Figure 3, cell scratch and in vitro tube formation tests demonstrated that HE NPs have good healing and angiogenesis-promoting properties. These results suggest that this nanomedicine has therapeutic effects on wound healing.

[0038] (5) Animal efficacy experiments A full-thickness excision wound model of MRSA infection in BalbC mice was established, and the mice were treated with PBS (negative control), vancomycin (positive control), hesperidin, and emodin, respectively, and the co-assembled nanomedicine was used for treatment. During the treatment, the wound closure was observed by taking photos and the weight of the mice was measured. The drug was given once every two days. After two treatments, MRSA was collected from the wound tissue and diluted and plated to test its antibacterial effect. When the wound was close to closure, the mice were euthanized, and the wound skin tissue and major organs (heart, liver, spleen, lung, and kidney) and blood were taken for testing. Figure 7 As shown, the wound healing rate of the self-assembled nanoparticle treatment group was almost completely closed on the 10th day, which was significantly higher than that of the free drug group and the control group. In addition, the antibacterial effect of HE NPs at 40ug / mL was better than that of vancomycin at 2ug / mL.

[0039] like Figure 8As shown, H&E staining revealed that the epidermal structure of the control group was uniform but lacked signs of new tissue formation, indicating poor wound healing. The HE NPs-treated group not only displayed a large number of newly formed hair follicles but also had a dense and orderly epidermal structure, indicating optimal wound healing. Masson staining revealed greater collagen deposition in the wounds of mice treated with HE NPs, further improving wound healing quality. These results suggest that HE NPs promote wound healing by regulating granulation tissue formation and collagen deposition. Vascular endothelial growth factor (VEGF) and platelet endothelial cell adhesion molecule (CD31), two angiogenesis-related cytokines that play a crucial role in tissue regeneration and wound healing, were examined using immunohistochemical staining. The results showed that HE NPs significantly increased their expression levels after treatment. Furthermore, inflammatory cytokines in the wound skin were measured, and HE NPs treatment effectively suppressed the expression of pro-inflammatory factors and promoted the expression of anti-inflammatory factors. In summary, HE NPs accelerated the healing of chronic wounds infected with MRSA through synergistic effects, including reducing wound infection, alleviating inflammation, and promoting granulation tissue formation, angiogenesis, and collagen deposition, thereby significantly improving the speed and quality of wound healing.

[0040] (6) In vivo biosafety experiments like Figure 9 As shown, during the treatment period, HE NPs did not show significant variability compared with the control group. WBC, RBC, HGB, and PLT parameters did not show significant toxicity and did not cause serious damage in the body. In addition, H&E staining showed that HENPs did not cause damage or toxicity to the normal anatomy of various organs. These results indicate that HE NPs are an effective and safe drug for treating MRSA-infected wounds. The above description of the disclosed embodiments enables professionals in this field to implement or use the present invention. Various modifications to these embodiments will be obvious to professionals in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing natural product co-assembled nanoparticles, characterized in that: Hesperidin and emodin are co-assembled into nanoparticles to obtain the product.

2. The preparation method according to claim 1, characterized in that The following steps are involved: The mixed solution of hesperidin and emodin is added dropwise into the polyvinyl alcohol aqueous solution, shaken to mix, ultrasonicated, centrifuged, and the precipitate is collected to obtain the product.

3. The preparation method according to claim 2, characterized in that The mixed solution of hesperidin and emodin was prepared by the following method: Prepare a hesperidin dimethyl sulfoxide solution with a concentration of 2.5-80 mM; Prepare a 2.5-80 mM emodin dimethyl sulfoxide solution; Then mix well and you have it.

4. The preparation method according to claim 2, characterized in that The mass percentage concentration of the polyvinyl alcohol aqueous solution is 0.1-1.0%; The mixed solution was added dropwise to the polyvinyl alcohol aqueous solution at a rate of 1 drop per second.

5. The preparation method according to claim 2, characterized in that The ultrasonic time is 2-5 minutes, the ultrasonic power is 15-40kHz, and the ultrasonic temperature is 25-30℃; The centrifugation time is 20-40 minutes, and the centrifugal speed is 12000-14000 rpm.

6. The preparation method according to any one of claims 2 to 5, characterized in that The volume ratio of the mixed solution of hesperidin and emodin to the polyvinyl alcohol aqueous solution is 1:(8-10).

7. The preparation method according to any one of claims 1 to 5, characterized in that The molar ratio of emodin to hesperidin is 4:1-1:

8.

8. Natural product co-assembled nanoparticles obtained by the preparation method according to any one of claims 1 to 7.

9. Use of the natural product co-assembled nanoparticles according to claim 8 in the preparation of drugs for antibacterial, anti-inflammatory, wound healing and scar formation inhibition.

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