A pollen carrier quercetin-iron ion-puerarin nanoparticle, a preparation method and application thereof

Abstract

This invention discloses a pollen-loaded quercetin-iron ion-puerarin nanoparticle, its preparation method, and its applications. The method involves obtaining pollen cavity microcarriers by removing the pollen cell wall from natural pollen. Iron ions mediate the coordination self-assembly of quercetin and puerarin, forming nanoparticles in situ within and on the surface of the pollen cavity, thus creating a pollen-loaded drug-containing composite nanoparticle system. The pollen-loaded drug-containing nanoparticles prepared by this invention can be used to prepare drugs for treating androgenetic alopecia. They utilize the natural structure of the pollen cavity to achieve efficient drug loading and sustained release. Iron ions, in conjunction with quercetin and puerarin, promote microcirculation in hair follicle blood vessels, inhibit 5α-reductase activity, reduce androgen receptor expression, and activate hair follicle stem cells, thereby reversing the process of androgenetic alopecia through multiple pathways and promoting hair growth. This invention uses natural raw materials, employs a simple and easy pollen processing method, exhibits good biocompatibility, multiple functions, significant therapeutic effects, and has a wide range of applications.

Description

Technical Field

[0001] This invention relates to the fields of biomedicine and nanoparticle technology, specifically to a pollen-loaded quercetin-iron-puerarin nanoparticle for treating androgenetic alopecia, its preparation method, and its application. Background Technology

[0002] Androgenetic alopecia (AGA) is the most common type of hair loss in clinical practice. Its pathological mechanism is mainly related to the effects of androgens (such as dihydrotestosterone, DHT) on hair follicles. After DHT binds to androgen receptors in follicular papillary cells, it can regulate the expression of related genes, leading to follicle miniaturization, shortened growth phase, and ultimately thinning or even loss of hair. Currently, the drugs approved by the U.S. Food and Drug Administration (FDA) for the treatment of AGA mainly include oral finasteride and topical minoxidil. Finasteride reduces DHT production by inhibiting type II 5α-reductase, but may cause side effects such as sexual dysfunction; minoxidil can promote hair growth, but its exact mechanism is not yet clear, and it has disadvantages such as slow onset of action, need for long-term use, and easy relapse after discontinuation. Therefore, developing a highly effective, low-side-effect treatment strategy that can intervene in the hair loss process through multiple pathways is of great clinical significance.

[0003] Quercetin is a flavonoid compound widely found in natural plants, possessing antioxidant, anti-inflammatory, and 5α-reductase-inhibiting effects, and can reduce DHT production. Puerarin, the main active ingredient extracted from kudzu root, promotes vasodilation and improves local microcirculation, which is beneficial for hair follicle nutrient supply. Iron ions, as an essential trace element for the human body, play a crucial role in cell metabolism, enzyme activity regulation, and signal transduction. However, both quercetin and puerarin suffer from poor water solubility, instability, and limited skin permeability, limiting their application in transdermal drug delivery for the treatment of hair loss. Summary of the Invention

[0004] Objective of the Invention: The technical problem to be solved by this invention is to address the shortcomings of existing technologies by providing pollen-loaded quercetin-iron ion-puerarin nanoparticles for androgenetic alopecia and their preparation method. This invention utilizes a natural pollen carrier to load functional nanoparticles, achieving a synergistic effect of the antioxidant and anti-androgenic effects of quercetin, the cellular metabolic regulatory function of iron ions, and the vasodilatory effect of puerarin, effectively promoting hair follicle regeneration and prolonging the hair growth phase.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A pollen-loaded quercetin-iron-puerarin nanoparticle comprises a pollen microcarrier and quercetin-iron-puerarin nanoparticles loaded in the internal cavity and / or on the surface of the pollen microcarrier.

[0007] Specifically, the quercetin-iron ion-puerarin nanoparticles are spherical or near-spherical with a particle size of 50–200 nm.

[0008] Specifically, the pollen microcarrier has a particle size of 20–40 μm and its surface has a natural pore structure for the release of nanoparticles; the pollen-carrying quercetin-iron-puerarin nanoparticles have a particle size of 10–100 μm and a drug loading of 5%–30 wt%.

[0009] Specifically, in the quercetin-iron ion-puerarin nanoparticles, quercetin and puerarin are self-assembled through iron ion coordination and π-π stacking.

[0010] Furthermore, the present invention also provides a method for preparing the above-mentioned pollen-loaded quercetin-iron ion-puerarin nanoparticles, comprising the following steps:

[0011] (1) Preparation of pollen carriers: Natural pollen is degreased and dewalled to obtain pollen microcarriers with a cavity structure;

[0012] (2) Preparation of drug-loaded nanoparticles: Quercetin, puerarin and iron ion solution are mixed and quercetin-iron ion-puerarin nanoparticles are formed through iron ion-mediated coordination self-assembly.

[0013] (3) Loading nanoparticles: The nanoparticles obtained in step (2) are co-incubated with the pollen microcarriers obtained in step (1). The nanoparticles are then introduced into the cavity and surface of the pollen microcarriers by negative pressure or centrifugation. After washing and drying, the nanoparticles are obtained.

[0014] Preferably, in step (1), the defatting treatment is performed by reflux of ethanol or acetone; the cell wall removal treatment is performed by enzymatic hydrolysis or acid hydrolysis to remove the outer wall of the pollen, followed by centrifugation and washing until neutral.

[0015] Preferably, in step (2), the iron ion solution is a ferric chloride solution, and the molar ratio of quercetin, puerarin and ferric chloride is (2-5):(1-3):(1-2); the coordination self-assembly reaction has a pH of 7.0-9.0, a reaction temperature of 25-60℃, a reaction time of 1-12 hours, a stirring speed of 200-600 rpm, and a dropping speed of 0.5-2 mL / min.

[0016] Preferably, in step (3), the mass ratio of the nanoparticles to the pollen microcarriers is 1:2 to 1:20; and the co-incubation time is 2 to 24 hours.

[0017] Preferably, the natural pollen is selected from at least one of sunflower pollen, rapeseed pollen, or pine pollen.

[0018] Furthermore, the present invention also claims the use of the above-mentioned pollen-loaded quercetin-iron-puerarin nanoparticles in the preparation of a drug for treating androgenetic alopecia.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) The pollen-loaded quercetin-iron-puerarin nanoparticles provided by the present invention utilize quercetin to inhibit 5α-reductase and reduce the production of dihydrotestosterone, iron ions to regulate hair follicle cell metabolism and antioxidant pathways, and puerarin to dilate blood vessels around hair follicles and improve blood supply. The three work together to exert a comprehensive effect of anti-androgen, antioxidant and microcirculation promotion, and to intervene in the multiple causes of androgenetic alopecia.

[0021] (2) The present invention uses natural pollen as a carrier. Its unique surface spike structure and hollow cavity are conducive to anchoring and slow-release of drugs at the hair follicle opening, improving the retention time and bioavailability of drugs in the hair loss area, and reducing the systemic absorption side effects of transdermal administration.

[0022] (3) The preparation method of the present invention is simple to operate and mild, avoiding the problems of toxic crosslinking agents or organic solvent residues used in the preparation of traditional nanoparticles. The pollen-loaded nanoparticles obtained have good biosafety and stability, and are suitable for industrial production and clinical translation. Attached Figure Description

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0024] Figure 1 This is a schematic diagram of the preparation process of the pollen carrier of the present invention.

[0025] Figure 2 This is a schematic diagram of the preparation process of quercetin-iron ion-puerarin nanoparticles according to the present invention.

[0026] Figure 3 Scanning electron microscope (SEM) images of the original pollen and the acid-hydrolyzed pollen (a: original pollen, b: acid-hydrolyzed pollen), as well as particle size distribution diagrams c and d of the original pollen and acid-hydrolyzed pollen.

[0027] Figure 4 Transmission electron microscopy (TEM) images, particle size distribution diagrams, and zeta potential diagrams of quercetin-iron ion-puerarin nanoparticles.

[0028] Figure 5 These are confocal laser scanning microscope images of acid-hydrolyzed pollen and acid-hydrolyzed pollen loaded with fluorescent nanoparticles.

[0029] Figure 6 The images show the HE staining results of transverse and longitudinal sections of skin in the androgenetic alopecia model group, as well as the HE staining results of transverse and longitudinal sections of skin in the pollen-loaded quercetin-iron-puerarin nanoparticle treatment group. Detailed Implementation

[0030] The present invention can be better understood from the following embodiments.

[0031] Example 1

[0032] A method for preparing pollen-loaded quercetin-iron ion-puerarin nanoparticles includes the following steps:

[0033] (1) Preparation of pollen carriers: such as Figure 1 As shown, sunflower pollen was selected and defatted by reflux in a 40°C water bath with 70% ethanol for 2 hours. After centrifugation, the supernatant was discarded. Then, it was acid-hydrolyzed with 85% phosphoric acid at 60°C for 4 hours to remove the pollen outer wall. After centrifugation, it was repeatedly washed with deionized water until the pH was neutral. Finally, it was pre-frozen at -80°C and freeze-dried for 24 hours to obtain pollen microcarriers with a cavity structure. Scanning electron microscopy showed that the obtained pollen microcarriers had a particle size of approximately 30 μm, an intact surface, and a clear cavity structure.

[0034] Figure 3 These are scanning electron microscope (SEM) images and particle size distribution diagrams of the original pollen and the pollen after acid hydrolysis. It can be seen that a hollow, porous structure is obtained after acid hydrolysis.

[0035] (2) Preparation of drug-loaded nanoparticles: such as Figure 2 As shown, quercetin, puerarin, and ferric chloride were dissolved in anhydrous ethanol at a molar ratio of 3:1:1. Under conditions of stirring at 400 rpm, dropping at 1 mL / min, and reaction temperature of 25 °C, the organic phase was slowly added dropwise to deionized water at pH 8.0. The self-assembly reaction proceeded for 2 hours, forming quercetin-ferric ion-puerarin nanoparticles. Subsequently, ethanol was removed by rotary evaporation under reduced pressure (40 °C, vacuum degree -0.08 MPa) to obtain a nanoparticle suspension. Dynamic light scattering analysis showed that the average particle size of the obtained nanoparticles was 120 nm, and the Zeta potential was -25.6 mV.

[0036] (3) Loading nanoparticles: The nanoparticle suspension obtained in step 2 was mixed with the pollen microcarrier obtained in step 1 at a mass ratio of 10:1. The mixture was placed in a vacuum desiccator and evacuated to -0.08 MPa for 20 minutes. Then, the pressure was quickly restored to normal and the mixture was incubated for another 2 hours to allow the nanoparticles to enter the cavity and surface of the pollen microcarrier. The precipitate was then collected by centrifugation (3000 rpm, 10 minutes), washed three times with deionized water to remove the adsorbed drug on the surface, pre-frozen at -80℃, and freeze-dried for 36 hours to obtain pollen-loaded quercetin-iron-puerarin nanoparticles (PQFNs). High performance liquid chromatography (HPLC) analysis showed that the quercetin loading was 8.6% and the puerarin loading was 5.2%.

[0037] Figure 4 These are transmission electron microscopy (TEM) images, particle size distribution diagrams, and zeta potential diagrams of quercetin-iron ion-puerarin nanoparticles. It can be seen that the PQFNs exhibit relatively uniform spherical or near-spherical morphology and have a distinct surface structure; the particle size of the PQFNs is 155.4 ± 12 nm, and the corresponding zeta potentials are −8.865 ± 1.164 mV.

[0038] Figure 5 These are confocal laser scanning microscope images of acid-hydrolyzed pollen and acid-hydrolyzed pollen loaded with fluorescent nanoparticles. It can be seen that although the treated pollen grains retain their typical spiny morphology, the internal autofluorescence is significantly reduced after acid hydrolysis, indicating that the pollen components have been successfully removed. After loading fluorescently labeled PQFNs, strong green fluorescence is clearly visible inside the TPS, confirming that the nanoparticles have been efficiently encapsulated in the pollen-derived carrier.

[0039] Example 2

[0040] A method for preparing pollen-loaded quercetin-iron ion-puerarin nanoparticles includes the following steps:

[0041] (1) Preparation of pollen carriers: Rapeseed pollen was selected and defatted by reflux in a 40℃ water bath with acetone for 2 hours. After centrifugation, the supernatant was discarded. Then, it was treated with enzymatic hydrolysis (2% cellulase and 1% pectinase, pH 5.0, 50℃) for 6 hours to remove the pollen outer wall. After centrifugation, it was repeatedly washed with deionized water until neutral. Finally, it was pre-frozen at -80℃ and freeze-dried for 48 hours to obtain pollen microcarriers. Scanning electron microscopy showed that the pollen particle size was about 25 μm and the cavity structure was intact.

[0042] (2) Preparation of drug-loaded nanoparticles: Quercetin, puerarin, and ferric chloride were dissolved in methanol at a molar ratio of 4:2:1.5. Under the conditions of stirring speed of 500 rpm, dropping speed of 1.5 mL / min, and reaction temperature of 30 °C, the organic phase was slowly added dropwise to deionized water with pH 8.5. The self-assembly reaction was carried out for 3 hours to form nanoparticles. Subsequently, methanol was removed by rotary evaporation under reduced pressure to obtain a nanoparticle suspension. The average particle size of the obtained nanoparticles was 95 nm by dynamic light scattering measurement.

[0043] (3) Loading nanoparticles: The nanoparticle suspension obtained in step 2 was mixed with the pollen microcarrier obtained in step 1 at a mass ratio of 15:1. The nanoparticles were introduced into the pollen cavity by an alternating pressurization method (pressurized to 0.2 MPa and held for 10 minutes, released to atmospheric pressure and held for 10 minutes, repeated 3 times). The precipitate was then collected by centrifugation (3500 rpm, 10 minutes), washed 4 times with deionized water to remove the adsorbed drug on the surface, pre-frozen at -80℃ and freeze-dried for 48 hours to obtain pollen-loaded quercetin-iron-puerarin nanoparticles. The quercetin loading was 10.2% and the puerarin loading was 6.8% as determined by high performance liquid chromatography.

[0044] Example 3

[0045] A method for preparing pollen-loaded quercetin-iron ion-puerarin nanoparticles includes the following steps:

[0046] (1) Preparation of pollen carriers: Pine pollen was selected and defatted by reflux in a 40°C water bath with 70% ethanol for 3 hours. After centrifugation, the supernatant was discarded. Then, it was acid-hydrolyzed with 85% phosphoric acid at 70°C for 3 hours to remove the outer wall of the pollen. After centrifugation, it was repeatedly washed with deionized water until neutral. Finally, it was pre-frozen at -80°C and freeze-dried for 30 hours to obtain pollen microcarriers. Scanning electron microscopy showed that the pollen particle size was about 35 μm and the cavity structure was clear.

[0047] (2) Preparation of drug-loaded nanoparticles: Quercetin, puerarin, and ferric chloride were dissolved in anhydrous ethanol at a molar ratio of 2:1:1. Under the conditions of stirring speed of 300 rpm, dropping speed of 0.8 mL / min, and reaction temperature of 35℃, the organic phase was slowly added dropwise to deionized water with pH 7.5. The self-assembly reaction was carried out for 5 hours to form nanoparticles. Subsequently, the ethanol was removed by rotary evaporation under reduced pressure to obtain a nanoparticle suspension. The average particle size of the obtained nanoparticles was 150 nm by dynamic light scattering measurement.

[0048] (3) Loading nanoparticles: The nanoparticle suspension obtained in step 2 was mixed with the pollen microcarrier obtained in step 1 at a mass ratio of 5:1. The mixture was placed in a vacuum desiccator and evacuated to -0.08 MPa for 30 minutes. Then, the pressure was quickly restored to normal and the mixture was incubated for another 4 hours to allow the nanoparticles to enter the cavity and surface of the pollen microcarrier. The precipitate was then collected by centrifugation (2500 rpm, 10 minutes), washed three times with deionized water, pre-frozen at -80℃, and freeze-dried for 40 hours to obtain pollen-loaded quercetin-iron-puerarin nanoparticles. The quercetin loading was 7.2% and the puerarin loading was 4.1% as determined by high performance liquid chromatography.

[0049] Example 4

[0050] A method for preparing pollen-loaded quercetin-iron ion-puerarin nanoparticles includes the following steps:

[0051] (1) Preparation of pollen carriers: Sunflower pollen was selected and defatted by reflux in a 40°C water bath with 70% ethanol for 2 hours. After centrifugation, the supernatant was discarded. Then, it was treated with enzymatic hydrolysis (1.5% cellulase and 0.5% pectinase, pH 4.8, 55°C) for 8 hours to remove the outer wall of the pollen. After centrifugation, it was repeatedly washed with deionized water until neutral. Finally, it was pre-frozen at -80°C and freeze-dried for 36 hours to obtain pollen microcarriers.

[0052] (2) Preparation of drug-loaded nanoparticles: Quercetin, puerarin, and ferric chloride were dissolved in anhydrous ethanol at a molar ratio of 5:3:2. Under the conditions of stirring speed of 600 rpm, dropping speed of 2 mL / min, and reaction temperature of 25℃, the organic phase was slowly added dropwise to deionized water with pH 9.0. The self-assembly reaction was carried out for 1.5 hours to form nanoparticles. Subsequently, the ethanol was removed by rotary evaporation under reduced pressure to obtain a nanoparticle suspension. The average particle size of the obtained nanoparticles was 80 nm by dynamic light scattering measurement.

[0053] (3) Loading nanoparticles: The nanoparticle suspension obtained in step 2 was mixed with the pollen microcarrier obtained in step 1 at a mass ratio of 20:1. The nanoparticles were introduced into the pollen cavity by an alternating pressurization method (pressurized to 0.15 MPa and held for 15 minutes, released to atmospheric pressure and held for 15 minutes, repeated twice). The precipitate was then collected by centrifugation (3000 rpm, 10 minutes), washed four times with deionized water, pre-frozen at -80℃, and freeze-dried for 44 hours to obtain pollen-loaded quercetin-iron-puerarin nanoparticles. The quercetin loading was 9.5% and the puerarin loading was 6.1% as determined by high performance liquid chromatography.

[0054] Comparative Example 1: Preparation of Single-Drug Pollen Nanoparticles

[0055] To compare the synergistic effect of the present invention, pollen nanoparticles loaded only with quercetin (without adding puerarin and iron ions during the preparation process) and pollen nanoparticles loaded only with puerarin (without adding quercetin and iron ions during the preparation process) were prepared according to the method of Example 1.

[0056] Efficacy Verification Example: Evaluation of Treatment Efficacy in a Mouse Model of Androgenetic Alopecia

[0057] Experimental methods:

[0058] A male C57BL / 6 mouse model of androgenetic alopecia was established by subcutaneous injection of dihydrotestosterone (1 mg / kg) daily for 14 days after dorsal hair removal. The successfully modeled mice were randomly divided into 5 groups (n=8 per group): model control group (saline), positive control group (5% minoxidil), quercetin pollen nanoparticle group, puerarin pollen nanoparticle group, and the PQFNs group of this invention. Each group received the corresponding drug (10 mg / kg of total drug) applied daily to the hair-removed area for 21 consecutive days. After the last administration, dorsal skin was harvested for HE staining and immunohistochemistry.

[0059] Experimental results:

[0060] Twenty-one days after administration, the skin of the hairless area in the model control group mice was smooth, with only a small amount of sparse, fine, soft vellus hair, and the hair growth coverage was less than 10%. The hairless area in the positive control group (minoxidil) mice showed obvious hair growth, with a coverage of about 60%. The quercetin group and puerarin group showed moderate hair growth, with coverage of about 40% and 35%, respectively. In contrast, the hair in the hairless area of ​​the mice in the PQFNs group of this invention was dense, black, and had thick hair shafts, with a coverage of about 85%. The hair growth rate and density were significantly better than those of the other administration groups (p<0.01).

[0061] HE staining results:

[0062] Model control group: Significantly reduced number of hair follicles, with follicles atrophying and shifting upwards, and thinning of the dermis. Positive control group: Increased number of hair follicles compared to the model group, with some follicles returning to the anagen phase. Quercetin group: Moderate increase in the number of hair follicles (approximately 40%), with some telogen effluvium follicles still visible. Puerarin group: Slight increase in the number of hair follicles (approximately 30%), with a weaker improvement effect than the quercetin group. This invention group: The number of hair follicles significantly recovered to near-normal levels (approximately 90%), with intact follicle morphology, a large number of follicles in the anagen phase, and restored dermal thickness.

[0063] The pollen-loaded quercetin-iron-puerarin nanoparticles provided by this invention, through the synergistic effect of quercetin, iron, and puerarin, can significantly inhibit 5α-reductase activity, reduce DHT levels, promote angiogenesis, and activate hair follicle stem cells. The nanoparticles of this invention, through the ternary synergy of quercetin, iron, and puerarin, significantly inhibit 5α-reductase activity (inhibition rate of 91.5% at 100 μM), reducing skin DHT levels by 64.3%. Simultaneously, the iron-mediated angiogenesis increases the number of new blood vessels by 48.8% and activates the Wnt / β-catenin pathway, increasing the expression of the hair follicle stem cell marker KRT15 by 75.1%. These combined effects are significantly superior to those of individual drug groups, confirming that this invention has multiple synergistic therapeutic advantages in inhibiting androgens, improving microcirculation, and activating hair follicle stem cells. Therefore, it effectively reverses the progression of androgenetic alopecia and promotes hair growth, with its comprehensive efficacy superior to pollen nanoparticles loaded with a single drug.

[0064] This invention provides a method for preparing and applying pollen-loaded quercetin-iron ion-puerarin nanoparticles. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A pollen-loaded quercetin-iron ion-puerarin nanoparticle, characterized in that, This includes pollen microcarriers, and quercetin-iron ion-puerarin nanoparticles loaded in the internal cavities and / or on the surface of the pollen microcarriers.

2. The pollen-loaded quercetin-iron ion-puerarin nanoparticles according to claim 1, characterized in that, The quercetin-iron-puerarin nanoparticles are spherical or near-spherical in shape, with a particle size of 50–200 nm.

3. The pollen-loaded quercetin-iron ion-puerarin nanoparticles according to claim 1, characterized in that, The pollen microcarrier has a particle size of 20–40 μm and a natural pore structure on its surface, which serves as a release channel for the nanoparticles; the pollen-carrying quercetin-iron-puerarin nanoparticles have a particle size of 10–100 μm and a drug loading of 5%–30 wt%.

4. The pollen-loaded quercetin-iron ion-puerarin nanoparticles according to claim 1, characterized in that: In the quercetin-iron ion-puerarin nanoparticles, quercetin and puerarin are self-assembled through iron ion coordination and π-π stacking.

5. The method for preparing pollen-loaded quercetin-iron ion-puerarin nanoparticles according to any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Preparation of pollen carriers: Natural pollen is degreased and dewalled to obtain pollen microcarriers with a cavity structure; (2) Preparation of drug-loaded nanoparticles: Quercetin, puerarin and iron ion solution are mixed and quercetin-iron ion-puerarin nanoparticles are formed through iron ion-mediated coordination self-assembly. (3) Loading nanoparticles: The nanoparticles obtained in step (2) are co-incubated with the pollen microcarriers obtained in step (1). The nanoparticles are then introduced into the cavity and surface of the pollen microcarriers by negative pressure or centrifugation. After washing and drying, the nanoparticles are obtained.

6. The preparation method according to claim 5, characterized in that: In step (1), the defatting process is performed by reflux of ethanol or acetone; the cell wall removal process is performed by enzymatic hydrolysis or acid hydrolysis to remove the outer wall of the pollen, followed by centrifugation and washing until neutral.

7. The preparation method according to claim 5, characterized in that: In step (2), the iron ion solution is a ferric chloride solution, and the molar ratio of quercetin, puerarin and ferric chloride is (2-5):(1-3):(1-2); the coordination self-assembly reaction has a pH of 7.0-9.0, a reaction temperature of 25-60℃, a reaction time of 1-12 hours, a stirring speed of 200-600 rpm, and a dropping speed of 0.5-2 mL / min.

8. The preparation method according to claim 5, characterized in that: In step (3), the mass ratio of the nanoparticles to the pollen microcarriers is 1:2 to 1:20; the co-incubation time is 2 to 24 hours.

9. The preparation method according to claim 5, characterized in that: The natural pollen is selected from at least one of sunflower pollen, rapeseed pollen, or pine pollen.

10. The use of pollen-loaded quercetin-iron-puerarin nanoparticles according to any one of claims 1 to 4 in the preparation of a drug for treating androgenetic alopecia.

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