Plant volatile oil with broad-spectrum bactericidal effect and preparation method thereof

Abstract

The invention relates to the field of plant volatile oil, and discloses plant volatile oil with a broad-spectrum bactericidal effect and a preparation method thereof.The plant volatile oil with the broad-spectrum bactericidal effect is prepared from a plant volatile oil slow-release compound, menthol, vitamin E succinic acid ester, sodium dodecyl sulfate, sodium dodecyl sulfate and sodium dodecyl sulfate. The plant volatile oil slow-release compound is prepared by grafting aminated mesoporous zinc oxide prepared by a solvothermal method with masticinic acid, then loading plant volatile oil on the obtained masticinic acid grafted mesoporous zinc oxide and taking the plant volatile oil as a core material, and then preparing the plant volatile oil slow-release compound by taking hydroxypropyl-beta-cyclodextrin as a wall material. The preparation method comprises the following steps: carrying out water bath clathration to form a clathrate compound, carrying out hydrophobic modification on the surface of the clathrate compound by using n-octylene succinic anhydride, and finally mixing the modified clathrate compound, choline-lactic acid ionic liquid and TEMPO oxidized nanocellulose to prepare the plant volatile oil. After ultraviolet radiation, the antibacterial activity is not obviously changed, and the long-acting slow-release effect is still kept in a humid environment.

Description

Technical Field

[0001] The invention belongs to the technical field of plant volatile oils, and particularly relates to a plant volatile oil with a broad-spectrum bactericidal effect and a preparation method thereof. Background Art

[0002] Plant volatile oils, also known as essential oils, are a class of volatile oily liquids with a unique and strong odor, belonging to a class of plant-derived secondary metabolites. Natural plant essential oils have the characteristics of strong penetrating power, low molecular weight, easy absorption, and low resistance to drug resistance. Most plant volatile oils have a certain inhibitory effect on fungi and bacteria, and can be used as natural preservatives and antistaling agents. However, plant volatile oils are easily volatile and oxidized, have a short half-life, and are relatively unstable, resulting in low utilization and poor durability, which greatly limits their application range. In addition, existing technologies use highly hydrophilic wall materials to encapsulate plant volatile oils. However, highly hydrophilic wall materials easily absorb water in humid environments to form a hydration layer, which reduces the long-term sustained release effect of plant volatile oils, thus limiting their practical application. Summary of the Invention

[0003] In order to address the deficiencies mentioned in the above-mentioned background technology, the purpose of the present invention is to provide a plant volatile oil with a broad-spectrum bactericidal effect and a preparation method thereof. The plant volatile oil prepared by the present invention has a significant sustained-release effect, a strong ability to scavenge DPPH free radicals, high antioxidant activity, and excellent antibacterial properties. The antibacterial activity does not change significantly after ultraviolet irradiation, the ultraviolet stability is high, and the long-term sustained-release effect is still maintained in a humid environment.

[0004] The purpose of the present invention can be achieved through the following technical solutions: A plant volatile oil with a broad-spectrum bactericidal effect comprises the following components in parts by weight: 40-60 parts of a plant volatile oil sustained-release compound, 6-10 parts of menthol, and 3-8 parts of vitamin E succinate. The plant volatile oil sustained-release compound is prepared by a solvent thermal method, wherein aminated mesoporous zinc oxide is grafted with boswellic acid. The obtained boswellic acid-grafted mesoporous zinc oxide is loaded with the plant volatile oil as a core material. Subsequently, hydroxypropyl-β-cyclodextrin is used as a wall material, and inclusion complex is formed by water bath inclusion, and the surface of the inclusion complex is hydrophobically modified by n-octenylsuccinic anhydride. Finally, the modified inclusion complex, choline-lactic acid ionic liquid, and TEMPO-oxidized nanocellulose are mixed to form the complex.

[0005] Preferably, the plant volatile oil is one or more combinations of tea tree oil, eucalyptus oil, cinnamon leaf oil, thyme oil, clove bud oil and lemongrass oil.

[0006] Preferably, the preparation method of the plant volatile oil sustained-release complex comprises the following steps: (1) Triethylene glycol is placed in a reactor and heated at 100-115°C for 0.5-1h. Zinc acetate dihydrate and dopamine hydrochloride are then added. The temperature is raised to 180-190°C under nitrogen and stirred for 2-3h. After the reaction is completed, the mixture is centrifuged, washed, and dried to obtain amino-modified mesoporous zinc oxide. (2) β-boswellic acid and dimethyl sulfoxide were placed in a reactor, stirred and mixed, and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added. The mixture was stirred at room temperature for 2-3 hours, and then amino-modified mesoporous zinc oxide was added. The reaction was continued at room temperature for 4-5 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to prepare boswellic acid-grafted mesoporous zinc oxide. (3) Boswellic acid-grafted mesoporous zinc oxide is mixed with plant essential oil and subjected to ultrasonic treatment, and then filtered and dried to prepare the loaded plant essential oil; (4) Hydroxypropyl-β-cyclodextrin was dissolved in deionized water, and then the loaded plant volatile oil was added and stirred at 40-45°C for 4-5 hours to form an inclusion compound. The inclusion compound was then dispersed in deionized water, and sodium hydroxide solution was added to adjust the pH value of the system to 8-8.5. Then, n-octenylsuccinic anhydride was added and stirred for 0.5-1 hour. After the reaction was completed, the pH value of the system was adjusted to 6.5-7 using hydrochloric acid solution. After washing and drying, the modified inclusion compound was prepared. (5) The modified inclusion complex was added with choline-lactic acid ionic liquid and ultrasonically treated for 0.5-1 h. After the ultrasonic treatment, a 2% mass concentration of TEMPO oxidized nanocellulose dispersion was added and stirred for 1-2 h to prepare a plant volatile oil sustained-release complex.

[0007] Preferably, in step (1), the addition ratio of triethylene glycol, zinc acetate dihydrate and dopamine hydrochloride is 35-50 mL: 0.15-0.2 g: 0.01-0.02 g.

[0008] Preferably, in step (2), the mass ratio of β-boswellic acid to amino-modified mesoporous zinc oxide is 10-20:1.

[0009] Preferably, in step (4), the mass ratio of the inclusion compound to n-octenylsuccinic anhydride is 1:0.005-0.025.

[0010] Preferably, in step (5), the mass ratio of the modified inclusion compound, the choline-lactic acid ionic liquid and the TEMPO-oxidized nanocellulose is 1:0.5~1:0.1~0.2.

[0011] Preferably, the preparation step of the choline-lactic acid ionic liquid in step (5) is specifically as follows: adding lactic acid with a mass concentration of 80-85% to a choline hydroxide solution with a mass concentration of 40-45%, stirring for 20-24 hours, and then using a rotary evaporator to evaporate at 60-70°C for 2-3 hours, and then vacuum drying to prepare the choline-lactic acid ionic liquid.

[0012] A method for preparing a plant volatile oil with a broad-spectrum bactericidal effect comprises the following steps: weighing each component by weight, uniformly mixing a plant volatile oil sustained-release complex, menthol and vitamin E succinate to prepare the plant volatile oil with a broad-spectrum bactericidal effect.

[0013] Beneficial effects of the present invention: The present invention utilizes a solvent thermal method to prepare amino mesoporous zinc oxide nanoparticles, then binds β-boswellic acid activated by 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide to the amino mesoporous zinc oxide through an amidation reaction, and loads plant volatile oil. Subsequently, the loaded plant volatile oil is used as a core material, hydroxypropyl-β-cyclodextrin is used as a wall material, and an inclusion complex is formed by water bath inclusion. The inclusion complex surface is hydrophobically modified using n-octenylsuccinic anhydride. Finally, the modified inclusion complex, choline-lactic acid ionic liquid, and TEMPO-oxidized nanocellulose are mixed to form a three-dimensional network structure through electrostatic interaction, and the active ingredient is gradually released to prepare a plant volatile oil sustained-release complex. The plant volatile oil prepared by the present invention has broad-spectrum bactericidal and antioxidant effects, high ultraviolet stability, and can achieve a sustained-release effect of the plant volatile oil. In addition, a good sustained-release effect is still maintained in a humid environment, which can greatly extend the efficacy period of the active ingredient. Among them, mesoporous zinc oxide has high chemical stability and light stability. The specific surface area and pore volume of mesoporous zinc oxide are reduced by grafting β-boswellic acid, thereby hindering the volatilization of plant volatile oils. In addition, β-boswellic acid has anti-inflammatory and antioxidant activities. By combining with mesoporous zinc oxide through a strong chemical bond, the oil dispersibility and stability of β-boswellic acid are improved. In addition, menthol added to plant volatile oils can enhance permeability and promote the absorption of active ingredients. Vitamin E succinate, as a fat-soluble antioxidant, protects the activity of plant volatile oils. It works synergistically with the β-boswellic acid component in the plant volatile oil sustained-release complex to delay the deterioration of plant volatile oils. DETAILED DESCRIPTION

[0014] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0015] Example 1 A method for preparing a plant volatile oil sustained-release complex comprises the following steps: (1) 40 mL of triethylene glycol was placed in a reactor and heated at 110 ° C for 1 h. Then, 0.18 g of zinc acetate dihydrate and 0.01 g of dopamine hydrochloride were added. The temperature was raised to 190 ° C under nitrogen conditions and stirred for 2 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to prepare amino-modified mesoporous zinc oxide. (2) 9.2 g of β-boswellic acid and 70 mL of dimethyl sulfoxide were placed in a reactor, stirred and mixed, and then 1.1 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.5 g of N-hydroxysuccinimide were added. The mixture was stirred at room temperature for 3 h, and then 0.5 g of amino-modified mesoporous zinc oxide was added. The reaction was continued at room temperature for 5 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to prepare boswellic acid-grafted mesoporous zinc oxide. (3) 1.7 g of boswellic acid-grafted mesoporous zinc oxide was mixed with 2 mL of tea tree oil and ultrasonically treated. The mixture was filtered and dried to prepare the loaded plant volatile oil. (4) 2 g of hydroxypropyl-β-cyclodextrin was dissolved in 40 mL of deionized water, and then 100 mg of loaded plant volatile oil was added. The mixture was stirred at 40 °C for 4 h to form an inclusion complex. 2 g of the inclusion complex was then dispersed in 50 mL of deionized water, and a 3% sodium hydroxide solution was added to adjust the pH value of the system to 8.5. 0.02 g of n-octenylsuccinic anhydride was then added and stirred for 0.5 h. After the reaction was completed, the pH value of the system was adjusted to 6.5 using a 0.1 mol / L hydrochloric acid solution. The mixture was then washed and dried to obtain a modified inclusion complex. (5) 10.6 g of lactic acid with a mass concentration of 85% was added to 27.5 g of choline hydroxide solution with a mass concentration of 44%, stirred for 24 h, and then rotary evaporated at 70 °C for 2 h using a rotary evaporator, followed by vacuum drying to obtain choline-lactic acid ionic liquid. 2 g of the modified inclusion complex was added to 2 g of choline-lactic acid ionic liquid and ultrasonically treated for 0.5 h. After the ultrasonic treatment, 8 mL of TEMPO oxidized nanocellulose dispersion with a mass concentration of 2% was added and stirred for 2 h to prepare a plant volatile oil sustained-release complex.

[0016] Example 2 A plant essential oil with a broad-spectrum bactericidal effect comprises the following components in parts by weight: 44 parts of the plant essential oil sustained-release complex prepared in Example 1, 6 parts of menthol, and 3.5 parts of vitamin E succinate.

[0017] The preparation method of the plant volatile oil with broad-spectrum bactericidal effect comprises the following steps: weighing each component by weight, uniformly mixing the plant volatile oil sustained-release complex, menthol and vitamin E succinate to prepare the plant volatile oil with broad-spectrum bactericidal effect.

[0018] Example 3 A plant essential oil with a broad-spectrum bactericidal effect comprises the following components in parts by weight: 52 parts of the plant essential oil sustained-release complex prepared in Example 1, 8 parts of menthol, and 5.5 parts of vitamin E succinate.

[0019] The preparation method of the above-mentioned plant volatile oil with broad-spectrum bactericidal effect is the same as that in Example 2.

[0020] Example 4 A plant essential oil with a broad-spectrum bactericidal effect comprises the following components in parts by weight: 57 parts of the plant essential oil sustained-release complex prepared in Example 1, 9 parts of menthol, and 7.2 parts of vitamin E succinate.

[0021] The preparation method of the above-mentioned plant volatile oil with broad-spectrum bactericidal effect is the same as that in Example 2.

[0022] Comparative Example 1 A method for preparing a plant volatile oil sustained-release complex comprises the following steps: (1) 40 mL of triethylene glycol was placed in a reactor and heated at 110 ° C for 1 h. Then, 0.18 g of zinc acetate dihydrate and 0.01 g of dopamine hydrochloride were added. The temperature was raised to 190 ° C under nitrogen conditions and stirred for 2 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to prepare amino-modified mesoporous zinc oxide. (2) 1.7 g of amino-modified mesoporous zinc oxide was mixed with 2 mL of tea tree oil and ultrasonically treated. The mixture was filtered and dried to prepare the loaded plant volatile oil. (3) 2 g of hydroxypropyl-β-cyclodextrin was dissolved in 40 mL of deionized water, and then 100 mg of loaded plant volatile oil was added and stirred at 40 °C for 4 h to form an inclusion complex. Then 2 g of the inclusion complex was dispersed in 50 mL of deionized water, and 3% sodium hydroxide solution was added to adjust the pH value of the system to 8.5. Then 0.02 g of n-octenylsuccinic anhydride was added and stirred for 0.5 h. After the reaction was completed, the pH value of the system was adjusted to 6.5 using 0.1 mol / L hydrochloric acid solution. After washing and drying, a modified inclusion complex was prepared. (4) 10.6 g of lactic acid with a mass concentration of 85% was added to 27.5 g of choline hydroxide solution with a mass concentration of 44%, stirred for 24 h, and then rotary evaporated at 70 °C for 2 h using a rotary evaporator, followed by vacuum drying to obtain choline-lactic acid ionic liquid. 2 g of the modified inclusion complex was added to 2 g of choline-lactic acid ionic liquid and ultrasonically treated for 0.5 h. After the ultrasonic treatment, 8 mL of TEMPO oxidized nanocellulose dispersion with a mass concentration of 2% was added and stirred for 2 h to prepare a plant volatile oil sustained-release complex.

[0023] Comparative Example 2 A method for preparing a plant volatile oil sustained-release complex comprises the following steps: (1) 40 mL of triethylene glycol was placed in a reactor and heated at 110 ° C for 1 h. Then, 0.18 g of zinc acetate dihydrate and 0.01 g of dopamine hydrochloride were added. The temperature was raised to 190 ° C under nitrogen conditions and stirred for 2 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to prepare amino-modified mesoporous zinc oxide. (2) 9.2 g of β-boswellic acid and 70 mL of dimethyl sulfoxide were placed in a reactor, stirred and mixed, and then 1.1 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.5 g of N-hydroxysuccinimide were added. The mixture was stirred at room temperature for 3 h, and then 0.5 g of amino-modified mesoporous zinc oxide was added. The reaction was continued at room temperature for 5 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to prepare boswellic acid-grafted mesoporous zinc oxide. (3) 1.7 g of boswellic acid-grafted mesoporous zinc oxide was mixed with 2 mL of tea tree oil and ultrasonically treated. The mixture was filtered and dried to prepare the loaded plant volatile oil. (4) Dissolve 2 g of hydroxypropyl-β-cyclodextrin in 40 mL of deionized water, then add 100 mg of the loaded plant volatile oil and stir at 40 °C for 4 h to form an inclusion complex; (5) 10.6 g of lactic acid with a mass concentration of 85% was added to 27.5 g of choline hydroxide solution with a mass concentration of 44%, stirred for 24 h, and then rotary evaporated at 70 °C for 2 h, followed by vacuum drying to obtain choline-lactic acid ionic liquid. 2 g of the inclusion complex was added to 2 g of choline-lactic acid ionic liquid and ultrasonically treated for 0.5 h. After the ultrasonic treatment, 8 mL of TEMPO oxidized nanocellulose dispersion with a mass concentration of 2% was added and stirred for 2 h to prepare a plant volatile oil sustained-release complex.

[0024] Comparative Example 3 A method for preparing a plant volatile oil sustained-release complex comprises the following steps: (1) 40 mL of triethylene glycol was placed in a reactor and heated at 110 ° C for 1 h. Then, 0.18 g of zinc acetate dihydrate and 0.01 g of dopamine hydrochloride were added. The temperature was raised to 190 ° C under nitrogen conditions and stirred for 2 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to prepare amino-modified mesoporous zinc oxide. (2) 9.2 g of β-boswellic acid and 70 mL of dimethyl sulfoxide were placed in a reactor, stirred and mixed, and then 1.1 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.5 g of N-hydroxysuccinimide were added. The mixture was stirred at room temperature for 3 h, and then 0.5 g of amino-modified mesoporous zinc oxide was added. The reaction was continued at room temperature for 5 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to prepare boswellic acid-grafted mesoporous zinc oxide. (3) 1.7 g of boswellic acid-grafted mesoporous zinc oxide was mixed with 2 mL of tea tree oil and ultrasonically treated. The mixture was filtered and dried to prepare the loaded plant volatile oil. (4) Take 2g of hydroxypropyl-β-cyclodextrin and dissolve it in 40mL of deionized water, then add 100mg of loaded plant volatile oil, place it at 40℃ and stir for 4h to form an inclusion complex, then disperse 2g of the inclusion complex in 50mL of deionized water, add 3% sodium hydroxide solution to adjust the pH value of the system to 8.5, then add 0.02g of n-octenylsuccinic anhydride and stir the reaction for 0.5h. After the reaction is completed, use 0.1mol / L hydrochloric acid solution to adjust the pH value of the system to 6.5, and then wash and dry to prepare a plant volatile oil sustained-release complex.

[0025] Comparative Example 4 A method for preparing a plant volatile oil sustained-release complex comprises the following steps: (1) 2 g of hydroxypropyl-β-cyclodextrin was dissolved in 40 mL of deionized water, and then 2 mL of tea tree oil was added. The mixture was stirred at 40 °C for 4 h to form an inclusion complex. 2 g of the inclusion complex was then dispersed in 50 mL of deionized water, and a 3% sodium hydroxide solution was added to adjust the pH value of the system to 8.5. 0.02 g of n-octenylsuccinic anhydride was then added and stirred for 0.5 h. After the reaction was completed, the pH value of the system was adjusted to 6.5 using a 0.1 mol / L hydrochloric acid solution. The mixture was then washed and dried to obtain a modified inclusion complex. (2) 10.6 g of lactic acid with a mass concentration of 85% was added to 27.5 g of choline hydroxide solution with a mass concentration of 44%, stirred for 24 h, and then rotary evaporated at 70 ° C for 2 h using a rotary evaporator, followed by vacuum drying to obtain choline-lactic acid ionic liquid. 2 g of the modified inclusion complex was added to 2 g of choline-lactic acid ionic liquid and ultrasonically treated for 0.5 h. After the ultrasonic treatment, 8 mL of TEMPO oxidized nanocellulose dispersion with a mass concentration of 2% was added and stirred for 2 h to prepare a plant volatile oil sustained-release complex.

[0026] Comparative Example 5 A plant essential oil with a broad-spectrum bactericidal effect comprises the following components in parts by weight: 57 parts of the plant essential oil sustained-release complex prepared in Comparative Example 1, 9 parts of menthol, and 7.2 parts of vitamin E succinate.

[0027] The preparation method of the above-mentioned plant volatile oil with broad-spectrum bactericidal effect is the same as that in Example 2.

[0028] Comparative Example 6 A plant essential oil with a broad-spectrum bactericidal effect comprises the following components in parts by weight: 57 parts of the plant essential oil sustained-release complex prepared in Comparative Example 2, 9 parts of menthol, and 7.2 parts of vitamin E succinate.

[0029] The preparation method of the above-mentioned plant volatile oil with broad-spectrum bactericidal effect is the same as that in Example 2.

[0030] Comparative Example 7 A plant essential oil with a broad-spectrum bactericidal effect comprises the following components in parts by weight: 57 parts of the plant essential oil sustained-release complex prepared in Comparative Example 3, 9 parts of menthol, and 7.2 parts of vitamin E succinate.

[0031] The preparation method of the above-mentioned plant volatile oil with broad-spectrum bactericidal effect is the same as that in Example 2.

[0032] Comparative Example 8 A plant essential oil with a broad-spectrum bactericidal effect comprises the following components in parts by weight: 57 parts of the plant essential oil sustained-release complex prepared in Comparative Example 4, 9 parts of menthol, and 7.2 parts of vitamin E succinate.

[0033] The preparation method of the above-mentioned plant volatile oil with broad-spectrum bactericidal effect is the same as that in Example 2.

[0034] Performance testing The plant essential oils prepared in Examples 2-4 and Comparative Examples 5-8 were subjected to performance tests: (1) Sustained-release performance: The sample was evenly spread on a culture dish and placed in an open environment at 25°C for 60 days. The content of plant volatile oil in the sample was determined using a TU-1950 UV-visible spectrophotometer to obtain the amount of plant volatile oil released. The data results are shown in Table 1.

[0035] (2) Detection of DPPH free radical scavenging ability: 2 mL of DPPH solution (0.2 mg / mL) was mixed evenly with 2 mL of sample. After reacting in the dark at room temperature for 30 min, the absorbance was measured at a wavelength of 517 nm. The scavenging rate was calculated according to the formula: DPPH free radical scavenging rate (%) = 1-(A2-A1) / A0×100%, where: A2 is the absorbance measured after the sample solution and DPPH solution are mixed; A1 is the absorbance measured after the sample solution and anhydrous ethanol are mixed; A0 is the absorbance measured after the DPPH solution and anhydrous ethanol are mixed. The data results are shown in Table 1.

[0036] (3) Antibacterial performance test: 200 μL of the bacterial suspension of the test strain was evenly spread on the beef extract peptone culture medium, 5 μL of the sample was dropped on a 6 mm sterile filter paper, and then the filter paper was placed on the coated culture medium, 3 pieces per dish, and incubated inverted at 37°C for 24 hours (48 hours for Staphylococcus aureus). After that, the diameter of each inhibition zone in the culture dish was measured by the cross-cross method. The data results are shown in Table 1.

[0037] (4) UV stability test: The samples were treated under UV light for 100 min, with a power of 15 W and a vertical distance of 20 cm. The antibacterial performance test was performed according to the above method. The data results are shown in Table 1.

[0038]

[0039] As can be seen from the data results in Table 1, the plant volatile oils prepared in Examples 2-4 of the present invention have a release rate of less than 22% after 60 days, a significant sustained-release effect, strong DPPH free radical scavenging ability, high antioxidant activity, and excellent antibacterial properties. After ultraviolet irradiation, there was no significant change in the antibacterial activity against Staphylococcus aureus and Escherichia coli, and the ultraviolet stability was high. Among them, the plant volatile oil sustained-release composite added in Comparative Example 5 was not grafted with β-boswellic acid, and its measured sustained-release effect and DPPH free radical scavenging rate were lower than those of Examples 2-4, indicating that the grafting of β-boswellic acid synergistically exerted antioxidant activity and enhanced the sustained-release effect to a certain extent. The plant volatile oil sustained-release composite added in Comparative Example 7 did not introduce choline-lactic acid ionic liquid and TEMPO-oxidized nanocellulose, and its measured sustained-release effect was worse than that of Examples 2-4. The reason is that the three-dimensional network structure formed by electrostatic interaction can further enhance the sustained-release effect. The plant volatile oil sustained-release composite added in Comparative Example 8 did not utilize boswellic acid grafted mesoporous zinc oxide to load the plant volatile oil, and its measured sustained-release effect, DPPH free radical scavenging rate and ultraviolet stability were lower than those of Examples 2-4, indicating that the introduction of boswellic acid grafted mesoporous zinc oxide improved the sustained-release effect, antioxidant activity and photostability of the plant volatile oil.

[0040] (5) Test of long-term antibacterial performance in a humid environment: The samples were placed in humid air at room temperature and a humidity of 80% RH for different days. The antibacterial performance of the samples was tested using the Oxford cup method. Aspergillus niger and Trichoderma viride were inoculated on PDA culture medium respectively and cultured in a constant temperature and humidity chamber at room temperature and a relative humidity of 80%. After the colonies covered the entire culture medium, a sterile Oxford cup was placed in the culture medium, and 0.1 mL of a sample with a mass fraction of 1% prepared with 0.9% saline was slowly injected into the Oxford cup. The sample was transferred to a constant temperature and humidity chamber and continued to be cultured for 7 days. After the diffusion of the solution in the Oxford cup was completed, the diameter of the inhibition zone was measured. The data results are shown in Table 2.

[0041]

[0042] As can be seen from the data in Table 2, the plant essential oils prepared in Examples 2-4 of the present invention maintain a good long-term sustained-release effect in a humid environment. The plant essential oil sustained-release composite added in Comparative Example 6, which was not hydrophobically modified, exhibited poorer long-term antibacterial efficacy than that of Examples 2-4, indicating that the grafting of n-octenylsuccinic anhydride can enhance the sustained-release effect of plant essential oils in a humid environment.

[0043] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0044] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A plant volatile oil with broad-spectrum bactericidal effect, characterized in that: The invention comprises the following components in parts by weight: 40-60 parts of a plant volatile oil sustained-release complex, 6-10 parts of menthol, and 3-8 parts of vitamin E succinate. The plant volatile oil sustained-release complex is prepared by a solvent thermal method, wherein amino-modified mesoporous zinc oxide is grafted with boswellic acid. The obtained boswellic acid-grafted mesoporous zinc oxide is loaded with plant volatile oil as a core material. Hydroxypropyl-β-cyclodextrin is then used as a wall material to form an inclusion complex through water bath inclusion reaction. The surface of the inclusion complex is hydrophobically modified by using n-octenylsuccinic anhydride. Finally, the modified inclusion complex, choline-lactic acid ionic liquid, and TEMPO-oxidized nanocellulose are mixed to form the inclusion complex.

2. The plant volatile oil with broad-spectrum bactericidal effect according to claim 1, characterized in that The plant volatile oil is one or more combinations of tea tree oil, eucalyptus oil, cinnamon leaf oil, thyme oil, clove bud oil and lemongrass oil.

3. The plant volatile oil with broad-spectrum bactericidal effect according to claim 1, characterized in that The preparation method of the plant volatile oil sustained-release complex comprises the following steps: (1) Triethylene glycol is placed in a reactor and heated at 100-115°C for 0.5-1h. Zinc acetate dihydrate and dopamine hydrochloride are then added. The temperature is raised to 180-190°C under nitrogen and stirred for 2-3h. After the reaction is completed, the mixture is centrifuged, washed, and dried to obtain amino-modified mesoporous zinc oxide. (2) β-boswellic acid and dimethyl sulfoxide were placed in a reactor, stirred and mixed, and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added. The mixture was stirred at room temperature for 2-3 hours, and then amino-modified mesoporous zinc oxide was added. The reaction was continued at room temperature for 4-5 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to prepare boswellic acid-grafted mesoporous zinc oxide. (3) Boswellic acid-grafted mesoporous zinc oxide is mixed with plant essential oil and subjected to ultrasonic treatment, and then filtered and dried to prepare the loaded plant essential oil; (4) Hydroxypropyl-β-cyclodextrin was dissolved in deionized water, and then the loaded plant volatile oil was added and stirred at 40-45°C for 4-5 hours to form an inclusion compound. The inclusion compound was then dispersed in deionized water, and sodium hydroxide solution was added to adjust the pH value of the system to 8-8.

5. Then, n-octenylsuccinic anhydride was added and stirred for 0.5-1 hour. After the reaction was completed, the pH value of the system was adjusted to 6.5-7 using hydrochloric acid solution. After washing and drying, the modified inclusion compound was prepared. (5) The modified inclusion complex was added with choline-lactic acid ionic liquid and ultrasonically treated for 0.5-1 h. After the ultrasonic treatment, a 2% mass concentration of TEMPO oxidized nanocellulose dispersion was added and stirred for 1-2 h to prepare a plant volatile oil sustained-release complex.

4. The plant volatile oil with broad-spectrum bactericidal effect according to claim 3, characterized in that In the step (1), the addition ratio of triethylene glycol, zinc acetate dihydrate and dopamine hydrochloride is 35-50 mL: 0.15-0.2 g: 0.01-0.02 g.

5. The plant volatile oil with broad-spectrum bactericidal effect according to claim 3, characterized in that In the step (2), the mass ratio of β-boswellic acid to amino-modified mesoporous zinc oxide is 10-20:

1.

6. The plant volatile oil with broad-spectrum bactericidal effect according to claim 3, characterized in that In the step (4), the mass ratio of the inclusion compound to n-octenylsuccinic anhydride is 1:0.005-0.

025.

7. The plant volatile oil with broad-spectrum bactericidal effect according to claim 3, characterized in that In the step (5), the mass ratio of the modified inclusion compound, the choline-lactic acid ionic liquid and the TEMPO-oxidized nanocellulose is 1:0.5~1:0.1~0.

2.

8. The plant volatile oil with broad-spectrum bactericidal effect according to claim 3, characterized in that The preparation steps of the choline-lactic acid ionic liquid in step (5) are specifically as follows: adding lactic acid with a mass concentration of 80-85% to a choline hydroxide solution with a mass concentration of 40-45%, stirring for 20-24 hours, and then using a rotary evaporator to rotary evaporate at 60-70° C. for 2-3 hours, followed by vacuum drying to prepare the choline-lactic acid ionic liquid.

9. A method for preparing a plant essential oil with a broad-spectrum bactericidal effect according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: weighing each component by weight, uniformly mixing the plant volatile oil slow-release compound, menthol and vitamin E succinate to prepare the plant volatile oil with broad-spectrum bactericidal effect.

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