Preparation method and application of 7-hydroxycoumarin modified iron-based metal organic framework composite

Abstract

This invention discloses a method for preparing and applying a 7-hydroxycoumarin-modified iron-based metal-organic framework composite material (7-HC-Fe-MOF). The method includes: loading 7-hydroxycoumarin onto an iron-based metal-organic framework via a solution impregnation method to obtain 7-HC-Fe-MOF. The preparation method involves: dissolving 7-hydroxycoumarin in anhydrous ethanol to prepare a 7-HC solution; adding Fe-MOF support to the 7-HC solution and stirring at room temperature in the dark for loading; after loading, centrifuging to collect the product, washing, and freeze-drying to obtain 7-HC-Fe-MOF. The 7-HC-Fe-MOF prepared by this invention can significantly inhibit the proliferation of MY11, the pathogen causing konjac soft rot, with high antibacterial efficiency and significantly weakening the pathogen's infectivity, demonstrating excellent control effects. It has good application prospects in the field of green antibacterial control agents for konjac soft rot. Furthermore, the preparation method is simple, mild, and reproducible, requiring no complex high-temperature and high-pressure equipment, making it easy to scale up and suitable for industrial application.

Description

Technical Field

[0001] This invention belongs to the field of biological control technology. More specifically, this invention relates to a method for preparing and applying a 7-hydroxycoumarin-modified iron-based metal-organic framework composite material. Background Technology

[0002] Konjac( Amorphophalluskonjac Konjac is an important economic crop in my country, with major production areas concentrated in Hubei, Shaanxi, Yunnan, Sichuan, Guizhou, and Chongqing. However, konjac has weak disease resistance and is highly susceptible to bacterial soft rot. This disease can occur throughout the entire growth period and post-harvest storage, often causing 20%–30% yield loss, and in severe cases, over 80% or even total crop failure, seriously hindering the sustainable development of the konjac industry. Currently, the control of konjac soft rot still heavily relies on chemical pesticides. Although some yield losses can be recovered, these methods generally suffer from low utilization rates, serious soil pollution, and high residue risks. Physical control methods (such as soil improvement and reasonable crop rotation) have drawbacks such as high labor consumption and slow effectiveness. Biological control also faces problems in actual production, including slow control effects, limited applicability, and susceptibility to environmental and climatic conditions. Therefore, developing efficient and green new control materials is of great significance for the prevention and control of konjac soft rot. Coumarin compounds are a class of natural plant secondary metabolites with insecticidal and antibacterial biological activities. As plant-derived pesticides, coumarins have advantages such as good environmental compatibility and low likelihood of developing resistance. However, most natural active substances often face problems such as poor photostability, low target utilization, and short duration of action, limiting their direct use as pesticides. Furthermore, there is currently a lack of systematic research on the control effects and mechanisms of action of coumarin compounds against bacterial soft rot. Metal-organic frameworks (MOFs) are a class of three-dimensional porous crystalline materials formed by the self-assembly of metal ions and organic ligands, characterized by high porosity, good biocompatibility, and strong pesticide loading capacity. Among them, MIL-101(Fe), as a biodegradable MOF material, can gradually decompose in the environment and release iron, which helps promote plant growth and is an ideal carrier material for constructing controlled-release pesticides.

[0003] Currently, there are no publicly available reports, either domestically or internationally, on the preparation of composite materials by loading 7-hydroxycoumarin (7-HC) onto MIL-101(Fe) and their application in inhibiting pathogens causing konjac soft rot and controlling the disease. Therefore, developing an iron-based metal-organic framework composite material loaded with 7-hydroxycoumarin to achieve efficient and green control of konjac soft rot is of significant innovative importance and application value. Summary of the Invention

[0004] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0005] To achieve these objectives and other advantages of the present invention, a 7-hydroxycoumarin-modified iron-based metal-organic framework composite material is provided, comprising: loading 7-hydroxycoumarin (7-HC) onto an iron-based metal-organic framework by a solution impregnation method to obtain a 7-hydroxycoumarin-modified iron-based metal-organic framework composite material.

[0006] Preferably, the mass ratio of 7-hydroxycoumarin to iron-based metal-organic framework used in the solution impregnation method is 2 to 6:1.

[0007] Preferably, the specific surface area of ​​the 7-hydroxycoumarin-modified iron-based metal-organic framework composite material is ≤499.01 m². 2 / g, total pore volume ≤0.281 cm³ 3 / g, maximum peak temperature of weight loss ≥633.0℃, drug loading ≥20.72%.

[0008] A method for preparing a 7-hydroxycoumarin-modified iron-based metal-organic framework composite material as described above includes the following steps: Step 1: Dissolve 7-hydroxycoumarin in anhydrous ethanol to prepare a 7-HC solution; Step 2: Add Fe-MOF support to the 7-HC solution and stir at room temperature in the dark to carry out loading; Step 3: After the loading is completed, the solid product is collected by centrifugation, washed, and freeze-dried to obtain the 7-hydroxycoumarin-modified iron-based metal-organic framework composite material.

[0009] Preferably, in step one, the concentration of 7-hydroxycoumarin in the 7-HC solution is 14~25 mg / mL.

[0010] Preferably, in step two, the Fe-MOF support is MIL-101(Fe), and the solid-liquid ratio of the Fe-MOF support to the 7-HC solution is 3~7 mg:1 mL.

[0011] Preferably, in step two, the stirring is magnetic stirring, and the stirring time is 16~32 h.

[0012] Preferably, in step three, the centrifugal force is 9000~11000 ×g, the centrifugation time is 5~15 min, the washing is performed with anhydrous ethanol 2~4 times, and the freeze-drying time is 20~28 h.

[0013] Preferably, the 7-hydroxycoumarin enters the pores of MIL-101(Fe), and the 7-hydroxycoumarin-modified iron-based metal-organic framework composite material maintains a regular octahedral morphology and a complete crystal skeleton structure.

[0014] The application of a 7-hydroxycoumarin-modified iron-based metal-organic framework composite material as described above, or a 7-hydroxycoumarin-modified iron-based metal-organic framework composite material prepared by the method described above, in the preparation of an antibacterial agent that inhibits the pathogenic bacterium MY11 of konjac soft rot.

[0015] Preferably, the antibacterial agent exerts its effect by inhibiting at least one of the cell growth ability and swimming motility of the konjac soft rot pathogen MY11, thereby achieving the inhibition and control of the konjac soft rot pathogen.

[0016] The present invention has at least the following beneficial effects: 1. The 7-hydroxycoumarin-modified iron-based metal-organic framework composite material prepared by this invention overcomes the problems of low-concentration growth promotion and limited antibacterial effect of single 7-hydroxycoumarin, as well as the weak antibacterial ability of pure MIL-101(Fe). It can significantly inhibit the proliferation of MY11 bacteria, the pathogen of konjac soft rot, even at low concentrations, with high antibacterial efficiency.

[0017] 2. The 7-hydroxycoumarin-modified iron-based metal-organic framework composite material prepared by this invention can significantly weaken the swimming and aggregation ability of pathogenic bacterium MY11 and block the migration and spread pathway of pathogenic bacteria. In addition, it can also significantly prevent MY11 from infecting konjac leaves, with excellent control effect and good application prospects in the field of green antibacterial control agents for konjac soft rot.

[0018] 3. The preparation method of the present invention is simple, mild, and reproducible. It does not require complex high-temperature and high-pressure equipment, is easy to prepare on a large scale, and is suitable for industrial application.

[0019] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0020] Figure 1 These are scanning electron microscope images of (a, b) Fe-MOF and (c, d) 7-HC-Fe-MOF of the present invention; Figure 2 Thermogravimetric analysis diagrams of 7-HC, Fe-MOF, and 7-HC-Fe-MOF of the present invention are shown below; Figure 3 The N2 adsorption-desorption curves of 7-HC, Fe-MOF and 7-HC-Fe-MOF of the present invention are shown below. Figure 4 This is a graph showing the linear relationship between the 7-HC mass concentration and peak area in this invention. Figure 5 The graph shows the growth inhibition effects of CK (ddH2O), 7-HC, Fe-MOF and 7-HC-Fe-MOF on MY11 in this invention. Figure 6 The image shows the plate counting results of MY11 after treatment with CK (ddH2O), 7-HC, Fe-MOF and 7-HC-Fe-MOF according to the present invention. Figure 7 This is a graph showing the effects of CK (ddH2O), 7-HC, Fe-MOF, and 7-HC-Fe-MOF on the motility of MY11. Figure 8 This diagram illustrates the effects of CK (ddH2O), 7-HC, Fe-MOF, and 7-HC-Fe-MOF on the migratory motion of MY11. Figure 9 The diagram shows the inhibitory effects of CK (ddH2O), Fe-MOF, 7-HC, and 7-HC-Fe-MOF on MY11-infected Amorphophallus konjac detached leaves. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0022] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0023] In this invention, MIL-101(Fe) is commercially available and purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., item number 103320.

[0024] In this invention, the formula for LB liquid culture medium is: 10 g tryptone, 5 g yeast extract, 10 g sodium chloride, and 1 L water; the formula for LB solid culture medium is: 10 g tryptone, 5 g yeast extract, 10 g sodium chloride, 15 g agar powder, and 1 L water.

[0025] Example 1 A method for preparing a 7-hydroxycoumarin-modified iron-based metal-organic framework composite material includes the following steps: Step 1: Dissolve 400 mg of 7-hydroxycoumarin in 20 mL of anhydrous ethanol to prepare a 7-HC solution with a concentration of 20 mg / mL. Step 2: Add 100 mg of MIL-101(Fe) to 20 mL of 7-HC solution to make the solid-liquid ratio of MIL-101(Fe) to 7-HC solution 5 mg: 1 mL, and impregnate by magnetic stirring at room temperature in the dark for 24 h. Step 3: After impregnation, centrifuge at 10000 ×g for 10 min, collect the solid product, wash it 3 times with anhydrous ethanol, and freeze-dry it in a freeze dryer for 24 h to obtain a yellow solid powder, namely the 7-hydroxycoumarin-modified iron-based metal-organic framework composite material, denoted as 7-HC-Fe-MOF.

[0026] Example 2 A method for preparing a 7-hydroxycoumarin-modified iron-based metal-organic framework composite material includes the following steps: Step 1: Dissolve 450 mg of 7-hydroxycoumarin in 25 mL of anhydrous ethanol to prepare a 7-HC solution with a concentration of 18 mg / mL. Step 2: Add 150 mg of MIL-101(Fe) to 25 mL of 7-HC solution to make the solid-liquid ratio of MIL-101(Fe) to 7-HC solution 6 mg: 1 mL, and impregnate by magnetic stirring at room temperature in the dark for 24 h. Step 3: After impregnation, centrifuge at 10000 ×g for 10 min, collect the solid product, wash it 3 times with anhydrous ethanol, and freeze-dry it in a freeze dryer for 24 h to obtain a yellow solid powder, namely the 7-hydroxycoumarin modified iron-based metal-organic framework composite material, denoted as 7-HC-Fe-MOF (3:1).

[0027] Example 3 A method for preparing a 7-hydroxycoumarin-modified iron-based metal-organic framework composite material includes the following steps: Step 1: Dissolve 420 mg of 7-hydroxycoumarin in 30 mL of anhydrous ethanol to prepare a 7-HC solution with a concentration of 14 mg / mL. Step 2: Add 210 mg of MIL-101(Fe) to 30 mL of 7-HC solution to make the solid-liquid ratio of MIL-101(Fe) to 7-HC solution 7 mg: 1 mL, and impregnate by magnetic stirring at room temperature in the dark for 24 h. Step 3: After impregnation, centrifuge at 10000 ×g for 10 min, collect the solid product, wash it 3 times with anhydrous ethanol, and freeze-dry it in a freeze dryer for 24 h to obtain a yellow solid powder, namely the 7-hydroxycoumarin modified iron-based metal-organic framework composite material, denoted as 7-HC-Fe-MOF (2:1).

[0028] Comparative Example 1 MIL-101(Fe) is used as an iron-based metal-organic framework material, denoted as Fe-MOF.

[0029] Figure 1 These are scanning electron microscope (SEM) images of the Fe-MOF (a, b) and 7-HC-Fe-MOF (c, d) of this invention. The microstructures of the Fe-MOF in Comparative Example 1 and the 7-HC-Fe-MOF prepared in Example 1 were observed using SEM, and the results are as follows: Figure 1 As shown, both Fe-MOF and 7-HC-Fe-MOF exhibit regular octahedral morphology, indicating that the loading process of 7-HC did not disrupt the crystal framework structure of the MOF. A small number of fine particles appear on the surface of 7-HC-Fe-MOF, which are presumably 7-HC aggregates that did not enter the pores and were physically adsorbed on the outer surface.

[0030] Figure 2 Thermogravimetric analysis (TGA) diagrams of 7-HC, Fe-MOF, and 7-HC-Fe-MOF of this invention are shown. Thermal stability analysis was performed on 7-HC, the Fe-MOF of Comparative Example 1, and the 7-HC-Fe-MOF prepared in Example 1; the results are as follows. Figure 2 As shown in a and 2b, 7-HC undergoes a rapid one-step decomposition at 250–350 °C, with a DTG peak temperature of 311.1 °C, resulting in nearly 100% weight loss. No residue is observed at 800 °C, confirming it as a completely volatile organic component. Fe-MOF exhibits multi-stage weight loss: 19.05% weight loss in the low-temperature region (150 °C), corresponding to solvent desorption; a gradual weight loss of approximately 29.64% in the mid-temperature region (150–500 °C), attributed to the breaking of weak coordination bonds and localized framework collapse; and a weight loss of 12.85% in the high-temperature region (500–650 °C), with the main DTG peak at 603.1 °C, attributed to the decomposition of organic ligands and inorganic phase transformation. Compared to Fe-MOF, the maximum weight loss peak temperature of 7-HC-Fe-MOF increases from 603.1 °C to 633.0 °C, indicating that the introduction of 7-HC enhances the thermal stability of the composite system and slows down the framework decomposition process.

[0031] Figure 3 The N2 adsorption-desorption curves of 7-HC, Fe-MOF, and 7-HC-Fe-MOF of the present invention are shown. N2 adsorption-desorption tests were performed on the Fe-MOF of Comparative Example 1 and the 7-HC-Fe-MOF prepared in Example 1, and the results are as follows: Figure 3 As shown in a and c, Fe-MOF exhibits typical type IV isotherms, accompanied by a significant hysteresis loop in the high-pressure region (P / P0>0.8), indicating that it possesses abundant mesoporous structure. Figure 3b). The isotherm of 7-HC-Fe-MOF still retains the mesoporous characteristics of the type IV isotherm, but the overall adsorption capacity is significantly reduced, and the adsorption ratio in the low relative pressure region is significantly decreased. Specific surface area and pore structure parameters are shown in Table 1. The specific surface area of ​​Fe-MOF after loading with 7-HC increased from 1087.39 m² / s². 2 / g decreased to 499.01 m 2 / g, total pore volume is 1.262 cm³ 3 / g decreased to 0.281 cm 3 / g, micropore volume from 0.409 cm³ 3 / g decreased to 0.174 cm 3 / g, the average pore size decreased from 4.64 nm to 2.25 nm. These results confirm that 7-HC molecules successfully entered the pores of Fe-MOF, occupying part of the micropore and mesopore space, leading to a significant reduction in the specific surface area and pore volume, and a decrease in the average pore size. This indicates that the pores were effectively modified after 7-HC was combined with Fe-MOF, and the changes in pore structure parameters further verify the successful construction of the composite structure.

[0032] Table 1 Specific surface area and pore size of Fe-MOF and 7-HC-Fe-MOF Figure 4 This is a linear relationship between the mass concentration and peak area of ​​7-HC in this invention. The drug loading rate was determined by high-performance liquid chromatography (HPLC). 7-HC was weighed, dissolved in anhydrous ethanol, and diluted to volume to prepare a stock solution with a concentration of 50 μg / mL. 0.2, 0.5, 1.0, 2.0, and 4.0 mL of this stock solution were respectively placed in 10 mL volumetric flasks, diluted to the mark with anhydrous ethanol, and shaken well to obtain a series of standard solutions with concentrations of 1, 2.5, 5, 10, and 20 μg / mL. After filtration through a 0.22 μm organic phase filter membrane, 10 μL of each solution was injected into the HPLC instrument for analysis. A 7-HC standard curve was plotted with concentration on the x-axis and peak area on the y-axis. 1 mL of the supernatant from step three of Example 1 was taken, diluted 100 times with anhydrous ethanol, filtered through a 0.22 μm filter membrane, and analyzed by HPLC to determine the mass of free 7-HC. The formula for calculating the drug loading rate is as follows: Drug loading rate (%) = Mass of 7-HC loaded / (Mass of carrier + Mass of 7-HC loaded) The linear relationship between the mass concentration of 7-HC and the peak area, as determined by HPLC, is as follows: Figure 4 As shown, the linear equation is y = 0.9169x - 0.9412, and the correlation coefficient R0 is... 2The value was 0.9999. This result indicates that 7-HC exhibits good linearity in the concentration range of 10–320 μg / mL, and the drug loading rate of 7-HC-Fe-MOF is 20.72%.

[0033] The drug loading rates of the 7-HC-Fe-MOFs prepared in Examples 2 and 3 were determined by HPLC under the same conditions as described above. The drug loading rate of 7-HC-Fe-MOF (3:1) was 16.07%; the drug loading rate of 7-HC-Fe-MOF (2:1) was 11.36%. The drug loading rates of the 7-HC-Fe-MOFs prepared in Examples 1-3 are shown in Table 2. Based on the drug loading rate determination results, the 7-HC-Fe-MOF prepared in Example 1 was selected for all three applications.

[0034] Table 2. Drug loading rates of 7-HC-Fe-MOF prepared in Examples 1-3 Application Example 1 The antibacterial effect of 7-HC-Fe-MOF on MY11, the pathogen of konjac soft rot: 1. Activation of pathogens (Refer to Cui Shuang, Chen Changlong, Feng Jiahao, et al. Pathogenic bacteria of konjac soft rot) Pectobacteriumaroidearum Characteristics and biocontrol effects of Bacillus belyssus [J]. Chinese Vegetables, 2021(3):83-93. Pathogens causing konjac soft rot Pectobacteriumaroidearum MY11 (hereinafter referred to as MY11) was isolated from a diseased konjac tuber sample from Sichuan Province. The specific isolation method was as follows: Single bacterial colonies were isolated from the konjac soft rot diseased tissue using the conventional streak plating method. The bacterial morphology was observed under a microscope, Gram staining was performed, and the bacteria were cultured on CVP selective medium (the specific formula of CVP selective medium is: 2 g peptone, 2 g calcium chloride, 10 g sodium citrate, 4 g sodium nitrate, 8 g agar powder, 3 mL 1% crystal violet aqueous solution, 4 mL 5 mmol / L sodium hydroxide solution, 36 g sodium polypectate, 1 L water, pH=7.0) to preliminarily screen for konjac soft rot pathogens. Single colonies of each test strain were inoculated into 10 mL of LB liquid medium and cultured at 180 rpm / min and 28℃ for 16 h with shaking. The culture was then washed three times with sterile water to prepare OD... 600 =0.2 bacterial suspension (i.e., 2×10 8The pathogen was inoculated into konjac tissue. Specific method: Using a sterile knife, a 4 mm × 4 mm cross-shaped wound, 2 mm deep, was made in the center of healthy konjac tubers and the base of the stem of potted plants. 10 μL of bacterial suspension was added to each wound, and the mixture was incubated at 28℃ for 24 h. The pathogen was then re-isolated and purified from the artificially inoculated diseased konjac tissue and stored at -80℃ for later use. The isolated and purified pathogen was sequenced, yielding a strain with the genome sequence JACERL000000000, which is identified as MY11, the pathogen causing konjac soft rot. This strain is currently stored at -80℃ in our laboratory. MY11 was inoculated into LB liquid medium for activation and cultured at 28℃ and 180 rpm / min for 12 h in a constant temperature shaking incubator. The culture was then diluted to a bacterial concentration of 10-1 during the logarithmic growth phase. 6 CFU / mL was used to obtain a suspension of MY11 bacteria.

[0035] 2. Inhibition of bacterial growth 7-HC-Fe-MOF dispersion was added to 5 mL of LB liquid medium to a final concentration of 0.1 mg / mL. A control group was prepared by adding equal volumes of 7-HC and Fe-MOF (at concentrations identical to the corresponding components in 7-HC-Fe-MOF), and a control group was prepared by adding an equal volume of ddH2O. Subsequently, 0.2% (v / v) MY11 bacterial suspension was inoculated, mixed thoroughly, and cultured in a shaker at 28℃ and 180 rpm / min. During the culture period, 50 μL of culture solution was spread evenly on LB solid medium at 0, 12, 24, 48, and 72 h. After 24 h of culture, the colony count was recorded, and the bacterial concentration (CFU / mL) was calculated.

[0036] Figure 5 The graph shows the growth inhibition effects of CK (ddH2O), 7-HC, Fe-MOF, and 7-HC-Fe-MOF on MY11. Figure 6 This image shows the plate count results of MY11 after treatment with CK (ddH2O), 7-HC, Fe-MOF, and 7-HC-Fe-MOF according to the present invention. Figure 6 In this study, the concentration of 7-HC-Fe-MOF was 0.1 mg / mL. Based on the drug loading of 7-HC-Fe-MOF (20.72%) in Example 1, a 7-HC single treatment group (concentration of 0.02 mg / mL) and a Fe-MOF single treatment group (concentration of 0.08 mg / mL) were set up for culture and coating experiments, and the operation method was the same as described above.

[0037] The antibacterial activities of 7-HC, Fe-MOF, and 7-HC-Fe-MOF against MY11 were systematically evaluated using the viable cell plate count method. Results ( Figure 5 and Figure 6 The results showed that, compared with the CK group, 7-HC-Fe-MOF treatment exhibited a significant antibacterial effect; after 48 h of culture, treatment with 0.1 mg / mL 7-HC-Fe-MOF significantly reduced the viable bacterial count by 61.04%. p <0.05).

[0038] Application Example 2 Effects of 7-HC-Fe-MOF on the motility of MY11, the pathogen causing soft rot of konjac: To evaluate the effect of 7-HC-Fe-MOF on the motility of MY11, swimming and swarming media were prepared. Both media were based on LB liquid medium, with the swimming medium containing 0.3% agar and the swarming medium containing 0.5% agar.

[0039] The experiment included a CK group (ddH2O), a 7-HC group, a Fe-MOF group, and a 7-HC-Fe-MOF group. For the latter three groups, 0.1 mg / mL of 7-HC-Fe-MOF and equal volumes of 7-HC and Fe-MOF dispersions (each component concentration matching the corresponding component content in 7-HC-Fe-MOF) were added to the unsolidified migratory and aggregation media, respectively. After thorough mixing, the mixture was poured into plates. Once solidified, the plates were left uncovered in a clean bench for 15 minutes to allow the surface to dry completely. Subsequently, 2 μL of MY11 bacterial suspension (concentration 10) was inoculated in the center of each plate. 6 The bacteria (CFU / mL) were incubated upright in a 28 ℃ incubator for 72 h. After incubation, the diameter of the bacterial motility zone was observed and measured to evaluate the inhibitory effect of each treatment group on the swimming and gregarious motility of MY11.

[0040] Figure 7 The diagram shows the effects of CK (ddH2O), 7-HC, Fe-MOF, and 7-HC-Fe-MOF on the motility of MY11. Figure 8 This diagram illustrates the effects of CK (ddH2O), 7-HC, Fe-MOF, and 7-HC-Fe-MOF on the motility of MY11. Results analysis: Bacterial motility (individual flagellated movement in a liquid environment) and gregarious movement (coordinated migration of a group on a solid surface) are two typical flagellated behaviors. To investigate the effect of 7-HC-Fe-MOF on the motility of MY11, the pathogen of konjac soft rot, the migration diameter of both motility and gregarious movement was determined using the semi-solid agar plate method. The results are shown below. Figure 7 and Figure 8 As shown. From Figure 7It can be seen that after 72 h of culture, the migration diameter of the 7-HC-Fe-MOF-treated group was smaller than that of the control group (CK), and the groups treated with 7-HC and Fe-MOF; after 72 h of culture, the aggregation movement of the 7-HC-Fe-MOF-treated group was also significantly inhibited. Figure 8 It can be seen that after 72 h of culture, the motility of MY11, the pathogen of konjac soft rot, was significantly weakened after treatment with 0.1 mg / mL 7-HC-Fe-MOF. The diameter of the motility after 72 h of culture was 55.67±1.15 mm, which was 18.54% lower than that of CK (p<0.05).

[0041] Application Example 3 Effects of 7-HC-Fe-MOF treatment on MY11 infection in detached leaves of Amorphophallus konjac: Healthy konjac leaves at the leaf expansion stage were immersed for 30 min in CK (ddH2O), 0.5 mg / mL 7-HC-Fe-MOF, and an equal volume of 7-HC and Fe-MOF dispersions (with concentrations consistent with the content of this component in 7-HC-Fe-MOF), respectively, to remove surface impurities and air dry. 5 μL of MY11 bacterial suspension (10 mg / mL) was added to the central vein of the leaf using a 1 mL syringe. 6 (CFU / mL) Place moistened filter paper in a glass petri dish, place the leaves inoculated with MY11 on the filter paper, keep them moist, and then incubate in a 28℃ incubator for 24 h. Observe the area of ​​lesions on the leaves infected with MY11.

[0042] Figure 9 The graph shows the inhibitory effects of CK (ddH2O), Fe-MOF, 7-HC, and 7-HC-Fe-MOF on MY11-infected Amorphophallus konjac detached leaves. The results are as follows: Figure 9 As shown, leaves soaked in ddH2O, free 7-HC and Fe-MOF showed obvious pathogen infection after 24 h, while konjac leaves treated with 7-HC-Fe-MOF did not show infection symptoms. This indicates that the composite material can significantly inhibit MY11 infection of konjac leaves.

[0043] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A 7-hydroxycoumarin-modified iron-based metal-organic framework composite material, characterized in that, include: 7-hydroxycoumarin was loaded onto an iron-based metal-organic framework via a solution impregnation method to obtain a 7-hydroxycoumarin-modified iron-based metal-organic framework composite material.

2. The 7-hydroxycoumarin-modified iron-based metal-organic framework composite material as described in claim 1, characterized in that, The mass ratio of 7-hydroxycoumarin to iron-based metal-organic framework used in the solution impregnation method is 2~6:

1.

3. The 7-hydroxycoumarin-modified iron-based metal-organic framework composite material as described in claim 1, characterized in that, The specific surface area of ​​the 7-hydroxycoumarin-modified iron-based metal-organic framework composite material is ≤499.01 m². 2 / g, total pore volume ≤0.281 cm³ 3 / g, maximum peak temperature of weight loss ≥633.0℃, drug loading ≥20.72%.

4. The method for preparing the 7-hydroxycoumarin-modified iron-based metal-organic framework composite material as described in claims 1-3, characterized in that, Includes the following steps: Step 1: Dissolve 7-hydroxycoumarin in anhydrous ethanol to prepare a 7-HC solution; Step 2: Add Fe-MOF support to the 7-HC solution and stir at room temperature in the dark to carry out loading; Step 3: After the loading is completed, the solid product is collected by centrifugation, washed, and freeze-dried to obtain the 7-hydroxycoumarin-modified iron-based metal-organic framework composite material.

5. The method for preparing the 7-hydroxycoumarin-modified iron-based metal-organic framework composite material as described in claim 4, characterized in that, In step one, the concentration of 7-hydroxycoumarin in the 7-HC solution is 14~25 mg / mL.

6. The method for preparing the 7-hydroxycoumarin-modified iron-based metal-organic framework composite material as described in claim 4, characterized in that, In step two, the Fe-MOF support is MIL-101(Fe), and the solid-liquid ratio of the Fe-MOF support and the 7-HC solution is 3~7 mg:1 mL.

7. The method for preparing the 7-hydroxycoumarin-modified iron-based metal-organic framework composite material as described in claim 4, characterized in that, In step two, the stirring is done by magnetic stirring, and the stirring time is 16~32 h.

8. The method for preparing the 7-hydroxycoumarin-modified iron-based metal-organic framework composite material as described in claim 4, characterized in that, In step three, the centrifugal force is 9000~11000 ×g, the centrifugation time is 5~15 min; the washing is done 2~4 times with anhydrous ethanol; and the freeze-drying time is 20~28 h.

9. The use of a 7-hydroxycoumarin-modified iron-based metal-organic framework composite material as described in any one of claims 1-3, or a 7-hydroxycoumarin-modified iron-based metal-organic framework composite material prepared by the preparation method as described in any one of claims 4-8, in the preparation of an antibacterial agent that inhibits the pathogenic fungus MY11 of konjac soft rot.

10. The application as described in claim 9, characterized in that, The antibacterial agent works by inhibiting at least one of the cell growth and swimming motility of MY11, the pathogen causing konjac soft rot.

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