Broad-spectrum bactericide containing natural plant extracts

Abstract

The invention relates to a broad-spectrum bactericide containing natural plant extracts, and relates to the technical field of pesticide bactericides, the broad-spectrum bactericide comprises the following raw materials by weight: 20-30 parts of plant extract compound nanocrystals, 4-6 parts of a nanocrystal stabilizer, 15-25 parts of a cosolvent, and 50-60 parts of deionized water. The broad-spectrum bactericide containing the natural plant extracts is good in broad-spectrum sterilization performance, remarkable and stable in sterilization effect and safe to use.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pesticide fungicide, in particular to a broad-spectrum fungicide containing natural plant extracts. BACKGROUND

[0002] In agricultural production, crop diseases have been an important factor affecting their yield and quality. Although traditional chemical fungicides have good fungicidal effect, long-term use can easily lead to drug resistance of pathogenic bacteria, and also pollute the environment and agricultural products, endangering human health. In this situation, broad-spectrum fungicides containing natural plant extracts have emerged, which have attracted widespread attention in the industry.

[0003] The fungicidal active ingredients (such as berberine, emodin, etc.) of natural plant extracts generally have problems such as poor water solubility, low light and heat stability, and insufficient transmembrane penetration efficiency, resulting in that the existing fungicides containing natural plant extracts have narrow fungicidal spectrum and unstable fungicidal effect, which are difficult to meet the prevention and control needs of various diseases in agricultural production. In addition, the existing broad-spectrum fungicides containing natural plant extracts often use simple extraction methods in the preparation process, resulting in low extraction rate of effective components and unstable active ingredients, thereby affecting the use effect and storage period of the fungicide.

[0004] In order to solve the above problems, a plant source agricultural fungicide and its preparation method are disclosed in the Chinese patent with the authorization publication number CN100577014C. The fungicide is made of traditional Chinese medicine asarum, turmeric and sophora flavescens, etc. The main effective components are asarum volatile oil, curcumin, turmeric ketone and sophoramine, etc. After the raw materials are extracted, various adjuvants are added to prepare emulsifiable concentrate, microemulsion, water emulsion, soluble liquid and other dosage forms. The fungicide has broad-spectrum inhibition effect on various plant pathogenic fungi. The plant source agricultural fungicide of the invention has the advantages of high efficiency, low toxicity, and pathogenic bacteria not easy to develop resistance, etc. Field tests show that the control effect on ginseng leaf spot is better than 70% mancozeb, and it can be used as an ideal environment-friendly pesticide. However, its fungicidal spectrum and fungicidal effect still need to be further improved.

[0005] It can be seen that it is in line with market demand to develop a broad-spectrum fungicide containing natural plant extracts with good fungicidal spectrum, significant and stable fungicidal effect, and safe use, which has wide market value and application prospect, and has very important significance for promoting the development of the field of agricultural fungicides. SUMMARY

[0006] The present application aims to overcome the deficiencies of the prior art and provide a broad-spectrum fungicide containing natural plant extracts with good fungicidal spectrum, significant and stable fungicidal effect, and safe use.

[0007] To achieve the above object, the technical scheme adopted by the present application is a broad-spectrum bactericide containing natural plant extracts, which comprises the following raw materials in parts by weight: plant extract compound nanocrystals 20-30 parts, nanocrystal stabilizer 4-6 parts, cosolvent 15-25 parts, and deionized water 50-60 parts.

[0008] Preferably, the cosolvent is ethanol.

[0009] Preferably, the nanocrystal stabilizer is a mixture of chitosan, other plant polysaccharides, and lecithin in a mass ratio of (1-2):(1-2):(0.5-1).

[0010] Preferably, the chitosan has a degree of deacetylation of greater than or equal to 90% and a weight average molecular weight of 10-20 kDa.

[0011] Preferably, the other plant polysaccharides are at least one of ginkgo leaf polysaccharides, seaweed polysaccharides, and porphyra polysaccharides.

[0012] Preferably, the preparation method of the plant extract compound nanocrystals comprises the following steps: Step S1, extraction of plant extract compound: mixing plant raw materials to obtain a mixture, adding citric acid buffer with pH=4.5 and complex enzymes, enzymatic hydrolysis for 2-4 hours, centrifugation for 15-25 minutes, collecting the supernatant; adding ethanol to extract the precipitate; combining the supernatant and the ethanol extract after centrifugation, and then filtering through a 0.25 mu m filter, reducing pressure to concentrate to a relative density of 1.15 at 25 DEG C to obtain a crude extract concentrate; Step S2, preparation of plant extract compound nanocrystals: uniformly dispersing the crude extract concentrate prepared in step S1 in a mixed solvent, adding lecithin, and ultrasonically treating for 13-18 minutes to obtain an oil phase; mixing chitosan solution and trehalose solution, and purging with nitrogen for 8-12 minutes to remove dissolved oxygen to obtain an aqueous phase; under constant temperature of 25 DEG C and mechanical stirring, the oil phase is added dropwise to the aqueous phase at a rate of 2 mL / min, and after the addition is completed, the stirring is continued for 25-35 minutes to form a primary nanocrystal suspension; the primary suspension is treated with a high-pressure homogenizer at 100-130 MPa for 5-8 cycles, and then filtered through a 0.22 mu m filter to obtain a nanocrystal suspension; Step S3, surface modification: slowly adding an ethanol solution of trimethoxysilane to the nanocrystal suspension at 48-52 DEG C under nitrogen protection, while maintaining the pH at 8.0-8.5 with ammonia water, and continuing the reaction for 1-2 hours after the addition is completed; centrifugation and freeze-drying to obtain plant extract compound nanocrystals.

[0013] Preferably, the plant raw materials in step S1 include the following components by weight: 8-10 parts Coptis chinensis, 6-8 parts Phellodendron chinense, 2-4 parts Rheum palmatum, 1-3 parts Scutellaria baicalensis, 3-5 parts Lonicera japonica, 1-2 parts Mentha haplocalyx, 4-6 parts Sophora flavescens, 3-5 parts Ginkgo biloba, 2-4 parts Rosemary, 1-3 parts Garlic, 2-4 parts Pine needles, 2-4 parts Eucommia ulmoides, and 1-3 parts Artemisia annua.

[0014] Preferably, the mass ratio of the mixture, citrate buffer, and complex enzyme in step S1 is 1:9:(0.03-0.05).

[0015] Preferably, the complex enzyme in step S1 is a mixture of cellulase EC 3.2.1.4 and pectinase EC 3.2.1.15 in a mass ratio of (1-2):1.

[0016] Preferably, the mass ratio of the precipitate to ethanol in step S1 is 1:(6-10).

[0017] Preferably, the ethanol extraction in step S1 is a heating reflux extraction, extracted twice, each time for 1-2 hours, and the two extracts are combined.

[0018] Preferably, the mixed solvent in step S2 is a mixture of ethyl acetate and ethanol in a volume ratio of 3:1.

[0019] Preferably, the mass ratio of the crude extract concentrate, mixed solvent, and lecithin in step S2 is (25-30):100:0.5.

[0020] Preferably, the method for preparing the chitosan solution in step S2 includes the following steps: dissolving chitosan in an aqueous acetic acid solution, stirring magnetically until completely dissolved, and then adjusting the pH to 5.5±0.1 with a 1 mol / L NaOH solution.

[0021] Preferably, the ratio of chitosan to acetic acid aqueous solution is (1-2) g / 100 mL; and the volume percentage concentration of acetic acid aqueous solution is 0.5%.

[0022] Preferably, the ratio of trehalose to water in the trehalose solution in step S2 is (4-5) g / 50 mL.

[0023] Preferably, the mass ratio of chitosan to trehalose in the aqueous phase in step S2 is 0.3:1.

[0024] Preferably, the volume ratio of the aqueous phase to the oil phase in step S2 is 5:1.

[0025] Preferably, in step S3, the volume ratio of trimethoxysilane to ethanol in the trimethoxysilane ethanol solution is 1:(8-10).

[0026] Preferably, the mass ratio of the ethanol solution of trimethoxysilane and the nanocrystal suspension in step S3 is (0.4-0.6):100.

[0027] Another object of the present application is to provide a preparation method of the broad-spectrum bactericide containing natural plant extracts, comprising the following steps: mixing each raw material uniformly according to weight parts, sterilizing, and preparing the broad-spectrum bactericide containing natural plant extracts.

[0028] Due to the use of the above technical solutions, the present application has the following beneficial effects: (1) The preparation method of the broad-spectrum bactericide containing natural plant extracts disclosed by the present application is simple and easy to operate, and has high preparation efficiency and product qualification rate, low dependence on equipment, and high popularization and application value.

[0029] (2) The broad-spectrum bactericide containing natural plant extracts disclosed by the present application comprises the following raw materials according to weight parts: plant extract compound nanocrystals 20-30 parts, nanocrystal stabilizer 4-6 parts, cosolvent 15-25 parts, and deionized water 50-60 parts. Through the mutual cooperation of each raw material, the prepared bactericide product has good broad-spectrum bactericidal property, significant and stable bactericidal effect, and safe use.

[0030] (3) The broad-spectrum bactericide containing natural plant extracts disclosed by the present application comprises the following components according to weight parts: Coptis 8-10 parts, Cortex Phellodendri 6-8 parts, Rhubarb 2-4 parts, Scutellaria 1-3 parts, Honeysuckle 3-5 parts, Mint 1-2 parts, Sophora 4-6 parts, Ginkgo leaves 3-5 parts, Rosemary 2-4 parts, Garlic 1-3 parts, Pine needles 2-4 parts, Eucommia 2-4 parts, and Artemisia annua 1-3 parts. Through the reasonable selection of the types and amounts of each plant raw material, they can effectively play a synergistic effect, and under the mutual cooperation, the bactericidal effect and stability can be better improved, and the broad-spectrum bactericidal property can be improved.

[0031] (4) The broad-spectrum bactericide containing natural plant extracts disclosed by the present application introduces bactericidal active ingredients in the form of plant extract compound nanocrystals, combines the characteristics of nanomaterials with the biocompatibility of organic components, has high specific surface area and strong adsorption, targeted action and sustained release, and multiple bactericidal mechanisms synergistically, can effectively improve the broad-spectrum bactericidal property and bactericidal effect, and make the bactericidal stability more excellent; it has significant advantages in efficiency, safety, stability and application, and provides a new direction for solving the drug resistance, toxicity and environmental problems of traditional bactericides.

[0032] (5) The broad-spectrum bactericide containing natural plant extracts disclosed by the application has higher bactericidal activity, better stability and rainwater washing resistance, and remarkable prevention and treatment effect on plant diseases and insect pests. DETAILED DESCRIPTION

[0033] The following description is provided to enable any person skilled in the art to practice the application. The preferred embodiments described in the following description are only examples of the application and other obvious variants can be conceived by those skilled in the art.

[0034] Embodiment 1 A broad-spectrum bactericide containing natural plant extracts comprises the following raw materials in parts by weight: plant extract compound nanocrystals 20 parts, nanocrystal stabilizer 4 parts, cosolvent 15 parts, and deionized water 50 parts.

[0035] The cosolvent is ethanol; the nanocrystal stabilizer is a mixture of chitosan, other plant polysaccharides and lecithin in a mass ratio of 1:1:0.5; the chitosan has a deacetylation degree of greater than or equal to 90% and a weight average molecular weight of 10 kDa; and the other plant polysaccharides are ginkgo leaf polysaccharides.

[0036] The preparation method of the plant extract compound nanocrystals comprises the following steps: Step S1, extraction of plant extract compound: plant raw materials are mixed to obtain a mixture, citric acid buffer solution with pH=4.5 and complex enzymes are added, and enzymolysis is performed for 2 hours; centrifugation is performed for 15 minutes, and the supernatant is collected; the precipitate is extracted with ethanol; the supernatant and the ethanol extract are combined, and the combined solution is subjected to 0.25 μm microfiltration, and then concentrated under reduced pressure to a relative density of 1.15 at 25℃ to obtain a crude extract concentrate; Step S2, preparation of plant extract compound nanocrystals: the crude extract concentrate prepared in step S1 is uniformly dispersed in a mixed solvent, lecithin is added, and ultrasonic treatment is performed for 13 minutes to obtain an oil phase; a chitosan solution and a trehalose solution are mixed, and nitrogen gas is introduced for 8 minutes to remove dissolved oxygen to obtain an aqueous phase; under the conditions of constant temperature 25℃ and mechanical stirring, the oil phase is added dropwise into the aqueous phase at a speed of 2 mL / min, and after the dropwise addition is completed, stirring is continued for 25 minutes to form a primary nanocrystal suspension; the primary suspension is subjected to cyclic treatment with a high-pressure homogenizer at 100 MPa for 5 times, and then filtered through a 0.22 μm filter membrane to obtain a nanocrystal suspension; Step S3, surface modification: an ethanol solution of trimethoxysilane is slowly added dropwise into the nanocrystal suspension under the conditions of 48℃ and nitrogen protection, and at the same time, ammonia water is used to maintain the pH at 8.0; after the dropwise addition is completed, the reaction is continued for 1 hour; after centrifugation, freeze-drying is performed to obtain plant extract compound nanocrystals.

[0037] The plant raw material in step S1 includes the following components by weight parts: Rhizoma Coptidis 8 parts, Cortex Phellodendri 6 parts, Radix et Rhizoma Rhei 2 parts, Radix Scophulariae 1 part, Flos Lonicerae 3 parts, Herba Menthae 1 part, Radix Sophorae Flavescentis 4 parts, Folium Ginkgo 3 parts, Rosmarinus officinalis 2 parts, Allium sativum 1 part, Pinus massoniana 2 parts, Eucommia ulmoides 2 parts, Artemisia annua 1 part; the mass ratio of the mixture, citric acid buffer and complex enzyme in step S1 is 1:9:0.03; the complex enzyme in step S1 is cellulase EC 3.2.1.4 and pectinase EC 3.2.1.15 mixed at a mass ratio of 1:1; the mass ratio of the precipitate and ethanol in step S1 is 1:6; the ethanol extraction in step S1 is heating reflux extraction, and the extraction is carried out twice, 1 hour each time, and the two extraction solutions are combined.

[0038] The mixed solvent in step S2 is ethyl acetate and ethanol mixed at a volume ratio of 3:1; the mass ratio of the crude extract concentrate, mixed solvent and lecithin in step S2 is 25:100:0.5; the preparation method of the chitosan solution in step S2 includes the following steps: chitosan is dissolved in an acetic acid aqueous solution, and magnetic stirring is carried out until complete dissolution, and then 1 mol / L NaOH solution is used to adjust the pH to 5.5±0.1; the mass ratio of the chitosan and acetic acid aqueous solution is 1g / 100mL; the volume percentage concentration of the acetic acid aqueous solution is 0.5%; the mass ratio of trehalose and water in the trehalose solution in step S2 is 4g / 50mL; the mass ratio of chitosan and trehalose in the aqueous phase in step S2 is 0.3:1; the volume ratio of the aqueous phase and oil phase in step S2 is 5:1; the volume ratio of trimethoxysilane and ethanol in the trimethoxysilane ethanol solution in step S3 is 1:8; the mass ratio of the trimethoxysilane ethanol solution and nanocrystal suspension in step S3 is 0.4:100.

[0039] A preparation method of the broad-spectrum bactericide containing natural plant extracts, including the following steps: after the raw materials are uniformly mixed by weight parts, sterilization is carried out to prepare the broad-spectrum bactericide containing natural plant extracts.

[0040] Example 2 A broad-spectrum bactericide containing natural plant extracts, including the following raw materials by weight parts: plant extract compound nanocrystal 23 parts, nanocrystal stabilizer 4.5 parts, cosolvent 17 parts, deionized water 53 parts.

[0041] The cosolvent is ethanol; the nanocrystal stabilizer is a mixture of chitosan, other plant polysaccharides and lecithin at a mass ratio of 1.2:1.3:0.6; the degree of deacetylation of the chitosan is greater than or equal to 90%, and the weight average molecular weight is 13kDa; the other plant polysaccharide is seaweed polysaccharide.

[0042] The preparation method of the plant extract compound nanocrystal includes the following steps: Step S1, extraction of plant extract complex: mixing plant raw materials to obtain a mixture, adding citric acid buffer solution with pH=4.5 and complex enzyme, enzymolysis for 2.5 hours, centrifugation for 17 minutes, collecting supernatant; adding ethanol to the precipitate for extraction; combining the supernatant and the ethanol extract after centrifugation, and then filtering through a 0.25 μm microfilter, concentrating under reduced pressure to a relative density of 1.15 at 25℃ to obtain a crude extract concentrate; Step S2, preparation of plant extract complex nanocrystals: uniformly dispersing the crude extract concentrate prepared in step S1 in a mixed solvent, adding lecithin, and ultrasonically treating for 14 minutes to obtain an oil phase; mixing chitosan solution and trehalose solution, and purging with nitrogen for 9 minutes to remove dissolved oxygen to obtain an aqueous phase; under the condition of constant temperature 25℃ and mechanical stirring, the oil phase is added dropwise into the aqueous phase at a speed of 2 mL / min, and after the dropwise addition is completed, the stirring is continued for 27 minutes to form a primary nanocrystal suspension; the primary suspension is treated with a high-pressure homogenizer at 110 MPa for 6 cycles, and then filtered through a 0.22 μm filter membrane to obtain a nanocrystal suspension; Step S3, surface modification: slowly adding an ethanol solution of trimethoxysilane into the nanocrystal suspension at 49℃ under nitrogen protection, while maintaining the pH at 8.1 with ammonia water, and continuing the reaction for 1.2 hours after the addition is completed; centrifugation and freeze-drying to obtain plant extract complex nanocrystals.

[0043] The plant raw materials in step S1 include the following components by weight: Huanglian 8.5 parts, Huangbai 6.5 parts, Dahuang 2.5 parts, Huangqin 1.5 parts, Jinyinhua 3.5 parts, Bohe 1.2 parts, Kushen 4.5 parts, Yinxingye 3.5 parts, Meirensang 2.5 parts, Daji 1.5 parts, Songzhen 2.5 parts, Duzhong 2.5 parts, Qinghao 1.5 parts; the mass ratio of the mixture, citric acid buffer solution and complex enzyme in step S1 is 1:9:0.035; the complex enzyme in step S1 is a mixture of cellulase EC 3.2.1.4 and pectinase EC 3.2.1.15 at a mass ratio of 1.3:1; the mass ratio of the precipitate and ethanol in step S1 is 1:7; the ethanol extraction in step S1 is heated reflux extraction, and the extraction is performed twice, each for 1.2 hours, and the two extraction solutions are combined; the mixed solvent in step S2 is a mixture of ethyl acetate and ethanol at a volume ratio of 3:1; the mass ratio of the crude extract concentrate, mixed solvent and lecithin in step S2 is 27:100:0.5.

[0044] The preparation method of the chitosan solution in step S2 comprises the following steps: dissolving chitosan in an acetic acid aqueous solution, magnetically stirring until completely dissolved, and then adjusting the pH to 5.5±0.1 by using a 1 mol / L NaOH solution; the amount ratio of the chitosan to the acetic acid aqueous solution is 1.3 g / 100 mL; the volume percentage concentration of the acetic acid aqueous solution is 0.5%; the amount ratio of trehalose to water in the trehalose solution in step S2 is 4.3 g / 50 mL; the mass ratio of chitosan to trehalose in the aqueous phase in step S2 is 0.3:1; the volume ratio of the aqueous phase to the oil phase in step S2 is 5:1; the volume ratio of trimethoxysilane to ethanol in the trimethoxysilane ethanol solution in step S3 is 1:8.5; and the mass ratio of the trimethoxysilane ethanol solution to the nanocrystal suspension in step S3 is 0.45:100.

[0045] A preparation method of the broad-spectrum bactericide containing natural plant extracts comprises the following steps: uniformly mixing raw materials according to weight parts, sterilizing, and preparing the broad-spectrum bactericide containing natural plant extracts.

[0046] Example 3 A broad-spectrum bactericide containing natural plant extracts comprises the following raw materials according to weight parts: plant extract compound nanocrystals 25 parts, nanocrystal stabilizer 5 parts, cosolvent 20 parts, and deionized water 55 parts.

[0047] The cosolvent is ethanol; the nanocrystal stabilizer is a mixture of chitosan, other plant polysaccharides, and lecithin according to a mass ratio of 1.5:1.5:0.8; the degree of deacetylation of the chitosan is greater than or equal to 90%, and the weight average molecular weight is 15 kDa; and the other plant polysaccharides are porphyra polysaccharides.

[0048] The preparation method of the plant extract compound nanocrystals comprises the following steps: Step S1, extraction of a plant extract compound: mixing plant raw materials to obtain a mixture, adding a citric acid buffer solution with a pH of 4.5 and a complex enzyme, enzymatically hydrolyzing for 3 hours, centrifuging for 20 minutes, and collecting a supernatant; adding ethanol to precipitate for extraction; combining the supernatant and the ethanol extraction liquid after centrifugation, performing microfiltration through a 0.25 μm filter, and reducing pressure to concentrate to a relative density of 1.15 at 25°C to obtain a crude extract concentrate; Step S2, preparation of plant extract complex nanocrystals: the concentrated extract prepared in step S1 was uniformly dispersed in a mixed solvent, lecithin was added, and ultrasonic treatment was performed for 15 minutes to obtain an oil phase; a chitosan solution and a trehalose solution were mixed, and nitrogen was introduced for 10 minutes to remove dissolved oxygen to obtain an aqueous phase; under the condition of constant temperature 25℃ and mechanical stirring, the oil phase was added dropwise into the aqueous phase at a speed of 2mL / min, and after the dropwise addition was completed, stirring was continued for 30 minutes to form a primary nanocrystal suspension; the primary suspension was treated with a high-pressure homogenizer at 115MPa for 7 cycles, filtered through a 0.22μm filter membrane to obtain a nanocrystal suspension; Step S3, surface modification: an ethanol solution of trimethoxysilane was slowly added dropwise into the nanocrystal suspension at 50℃ under the protection of nitrogen, and ammonia water was used to maintain the pH at 8.3, and after the dropwise addition was completed, the reaction was continued for 1.5 hours; after centrifugation, freeze-drying was performed to obtain plant extract complex nanocrystals.

[0049] The plant raw materials in step S1 include the following components in parts by weight: Huanglian 9 parts, Huangbai 7 parts, Dahuang 3 parts, Huangqin 2 parts, Jinyinhua 4 parts, Bohe 1.5 parts, Kuqian 5 parts, Yinxingye 4 parts, Meireixiang 3 parts, Dashi 2 parts, Songzhen 3 parts, Duzhong 3 parts, Qinghao 2 parts; the mass ratio of the mixture, the citric acid buffer solution and the complex enzyme in step S1 is 1:9:0.04; the complex enzyme in step S1 is a mixture of cellulase EC 3.2.1.4 and pectinase EC 3.2.1.15 at a mass ratio of 1.5:1; the mass ratio of the precipitate and ethanol in step S1 is 1:8; the ethanol extraction in step S1 is heated reflux extraction, and the extraction is performed twice, 1.5h each time, and the two extraction solutions are combined; the mixed solvent in step S2 is a mixture of ethyl acetate and ethanol at a volume ratio of 3:1; the mass ratio of the concentrated extract, the mixed solvent and lecithin in step S2 is 28:100:0.5.

[0050] The preparation method of the chitosan solution in step S2 includes the following steps: chitosan is dissolved in an acetic acid aqueous solution, and magnetic stirring is performed until complete dissolution, followed by adjusting the pH to 5.5±0.1 with 1mol / L NaOH solution; the amount ratio of chitosan to acetic acid aqueous solution is 1.5g / 100mL; the volume percentage concentration of the acetic acid aqueous solution is 0.5%; the amount ratio of trehalose to water in the trehalose solution in step S2 is 4.5g / 50mL; the mass ratio of chitosan to trehalose in the aqueous phase in step S2 is 0.3:1; the volume ratio of the aqueous phase to the oil phase in step S2 is 5:1; the volume ratio of trimethoxysilane to ethanol in the ethanol solution of trimethoxysilane in step S3 is 1:9; the mass ratio of the ethanol solution of trimethoxysilane to the nanocrystal suspension in step S3 is 0.5:100.

[0051] A preparation method of the broad-spectrum bactericide containing natural plant extracts, comprising the following steps: uniformly mixing raw materials according to weight parts, sterilizing, and preparing the broad-spectrum bactericide containing natural plant extracts.

[0052] Embodiment 4 A broad-spectrum bactericide containing natural plant extracts, comprising the following raw materials according to weight parts: plant extract compound nanocrystals 28 parts, nanocrystal stabilizer 5.5 parts, cosolvent 23 parts, and deionized water 58 parts.

[0053] The cosolvent is ethanol; the nanocrystal stabilizer is a mixture of chitosan, other plant polysaccharides, and lecithin in a mass ratio of 1.8:1.8:0.9; the chitosan has a degree of deacetylation of greater than or equal to 90% and a weight average molecular weight of 18 kDa; the other plant polysaccharides are a mixture of ginkgo leaf polysaccharides, seaweed polysaccharides, porphyra polysaccharides, and purple mushroom polysaccharides in a mass ratio of 1:2:2:1.

[0054] The preparation method of the plant extract compound nanocrystals comprises the following steps: Step S1, extraction of plant extract compound: mixing plant raw materials to obtain a mixture, adding citric acid buffer solution with pH=4.5 and complex enzymes, enzymolysis for 3.5 hours, centrifugation for 23 minutes, and collecting the supernatant; adding ethanol to extract the precipitate; combining the supernatant and the ethanol extract after centrifugation, and performing 0.25 μm microfiltration, reducing pressure concentration to a relative density of 1.15 at 25℃ to obtain a crude extract concentrate; Step S2, preparation of plant extract compound nanocrystals: uniformly dispersing the crude extract concentrate prepared in step S1 in a mixed solvent, adding lecithin, and ultrasonically treating for 17 minutes to obtain an oil phase; mixing chitosan solution and trehalose solution, introducing nitrogen for 11 minutes to remove dissolved oxygen, and obtaining an aqueous phase; under the conditions of constant temperature 25℃ and mechanical stirring, adding the oil phase into the aqueous phase at a speed of 2 mL / min, continuing to stir for 33 minutes after the addition is completed to form a primary nanocrystal suspension; treating the primary suspension with a high-pressure homogenizer at 125 MPa for 7 cycles, and filtering through a 0.22 μm filter membrane to obtain a nanocrystal suspension; Step S3, surface modification: slowly adding an ethanol solution of trimethoxysilane into the nanocrystal suspension at 51℃ under nitrogen protection, while maintaining the pH at 8.4 with ammonia water, continuing to react for 1.9 hours after the addition is completed; centrifugation and freeze-drying to obtain plant extract compound nanocrystals.

[0055] The plant raw material in step S1 includes the following components by weight parts: Coptis 9.5 parts, Phellodendron 7.5 parts, Rhubarb 3.5 parts, Scutellaria 2.5 parts, Honeysuckle 4.5 parts, Mint 1.9 parts, Sophora 5.5 parts, Ginkgo leaves 4.5 parts, Rosemary 3.5 parts, Garlic 2.5 parts, Pine needles 3.5 parts, Eucommia 3.5 parts, Artemisia annua 2.5 parts; the mass ratio of the mixture, citric acid buffer and complex enzyme in step S1 is 1:9:0.045; the complex enzyme in step S1 is cellulase EC 3.2.1.4 and pectinase EC 3.2.1.15 mixed at a mass ratio of 1.9:1; the mass ratio of the precipitate and ethanol in step S1 is 1:9.5; the ethanol extraction in step S1 is heated reflux extraction, and the extraction is performed twice, each for 1.9 hours, and the two extraction solutions are combined; the mixed solvent in step S2 is ethyl acetate and ethanol mixed at a volume ratio of 3:1; the mass ratio of the crude extract concentrate, mixed solvent and lecithin in step S2 is 29:100:0.5.

[0056] The preparation method of the chitosan solution in step S2 includes the following steps: dissolving chitosan in an acetic acid aqueous solution, magnetically stirring until completely dissolved, and then adjusting the pH to 5.5±0.1 with a 1 mol / L NaOH solution; the amount ratio of the chitosan and the acetic acid aqueous solution is 1.9 g / 100 mL; the volume percentage concentration of the acetic acid aqueous solution is 0.5%; the amount ratio of trehalose and water in the trehalose solution in step S2 is 4.8 g / 50 mL; the mass ratio of chitosan and trehalose in the aqueous phase in step S2 is 0.3:1; the volume ratio of the aqueous phase and the oil phase in step S2 is 5:1; the volume ratio of trimethoxysilane and ethanol in the trimethoxysilane ethanol solution in step S3 is 1:9.5; the mass ratio of the trimethoxysilane ethanol solution and the nanocrystal suspension in step S3 is 0.55:100.

[0057] A preparation method of the broad-spectrum bactericide containing natural plant extracts includes the following steps: mixing the raw materials uniformly by weight parts, sterilizing, and preparing the broad-spectrum bactericide containing natural plant extracts.

[0058] Example 5 A broad-spectrum bactericide containing natural plant extracts includes the following raw materials by weight parts: plant extract compound nanocrystals 30 parts, nanocrystal stabilizer 6 parts, cosolvent 25 parts, and deionized water 60 parts.

[0059] The cosolvent is ethanol; the nanocrystal stabilizer is a mixture of chitosan, other plant polysaccharides and lecithin at a mass ratio of 2:2:1; the degree of deacetylation of the chitosan is ≥90%, and the weight average molecular weight is 20 kDa; the other plant polysaccharides are Ganoderma lucidum polysaccharides.

[0060] The preparation method of the plant extract compound nanocrystal comprises the following steps: Step S1, extraction of the plant extract compound: mixing plant raw materials to obtain a mixture, adding citric acid buffer solution with pH=4.5 and a composite enzyme, enzymolysis for 4 hours, centrifugation for 25 minutes, and collecting the supernatant; adding ethanol to extract the precipitate; combining the supernatant and the ethanol extract solution obtained after centrifugation, and then performing microfiltration through a 0.25-micron filter, reducing pressure to concentrate the solution to a relative density of 1.15 at 25 DEG C to obtain a crude extract concentrate; Step S2, preparation of the plant extract compound nanocrystal: uniformly dispersing the crude extract concentrate prepared in step S1 in a mixed solvent, adding lecithin, and performing ultrasonic treatment for 18 minutes to obtain an oil phase; mixing a chitosan solution and a trehalose solution, and introducing nitrogen for 12 minutes to remove dissolved oxygen to obtain an aqueous phase; under the condition of constant temperature at 25 DEG C and mechanical stirring, the oil phase is added dropwise into the aqueous phase at a speed of 2 mL / min, and after the dropwise addition is completed, the stirring is continued for 35 minutes to form a primary nanocrystal suspension; the primary suspension is treated by a high-pressure homogenizer for 8 cycles at 130 MPa, and then filtered through a 0.22-micron filter to obtain a nanocrystal suspension; Step S3, surface modification: slowly adding an ethanol solution of trimethoxysilane into the nanocrystal suspension at 52 DEG C under the protection of nitrogen, and at the same time, using ammonia water to maintain the pH at 8.5, and after the addition is completed, the reaction is continued for 2 hours; after centrifugation, freeze-drying is performed to obtain the plant extract compound nanocrystal.

[0061] In step S1, the plant raw materials comprise the following components in parts by weight: Huanglian 10 parts, Huangbai 8 parts, Dahuang 4 parts, Huangqi 3 parts, Jinyinhua 5 parts, Bohe 2 parts, Kushen 6 parts, Yinxingye 5 parts, Meireixiang 4 parts, Dashi 3 parts, Songzhen 4 parts, Duzhong 4 parts, and Qinghao 3 parts; in step S1, the mass ratio of the mixture, the citric acid buffer solution and the composite enzyme is 1:9:0.05; in step S1, the composite enzyme is a mixture of cellulase EC 3.2.1.4 and pectinase EC 3.2.1.15 at a mass ratio of 2:1; in step S1, the mass ratio of the precipitate and ethanol is 1:10; in step S1, the ethanol extraction is heating reflux extraction, and the extraction is performed twice for 2 hours each time, and the two extraction solutions are combined; in step S2, the mixed solvent is a mixture of ethyl acetate and ethanol at a volume ratio of 3:1; in step S2, the mass ratio of the crude extract concentrate, the mixed solvent and lecithin is 30:100:0.5.

[0062] The preparation method of the chitosan solution in step S2 comprises the following steps: dissolving chitosan in an acetic acid aqueous solution, magnetically stirring until completely dissolved, and then adjusting the pH to 5.5±0.1 by using a 1 mol / L NaOH solution; the mass ratio of the chitosan to the acetic acid aqueous solution is 2 g / 100 mL; the volume percentage concentration of the acetic acid aqueous solution is 0.5%; the mass ratio of chitosan to trehalose in the aqueous phase in step S2 is 0.3:1; the volume ratio of the aqueous phase to the oil phase in step S2 is 5:1; the volume ratio of trimethoxysilane to ethanol in the trimethoxysilane ethanol solution in step S3 is 1:10; and the mass ratio of the trimethoxysilane ethanol solution to the nanocrystal suspension in step S3 is 0.6:100.

[0063] A preparation method of the broad-spectrum bactericide containing natural plant extracts comprises the following steps: uniformly mixing raw materials according to weight parts, sterilizing, and preparing the broad-spectrum bactericide containing natural plant extracts.

[0064] Comparative Example 1 A broad-spectrum bactericide containing natural plant extracts and a preparation method thereof are basically the same as those in Embodiment 1, except that an equal amount of a crude extract concentrate is used instead of the plant extract compound nanocrystal.

[0065] Comparative Example 2 A broad-spectrum bactericide containing natural plant extracts and a preparation method thereof are basically the same as those in Embodiment 1, except that steps S3 and surface modification are not performed, the nanocrystal suspension is directly centrifuged and freeze-dried, and pine needles and artemisia are not added.

[0066] In order to further illustrate the beneficial technical effects of the broad-spectrum bactericide containing natural plant extracts involved in the embodiments of the present application, the broad-spectrum bactericide containing natural plant extracts involved in Embodiments 1-5 and Comparative Examples 1-2 is subjected to relevant performance tests, and the test results are shown in Table 1, and the test methods are as follows: (1) Bacteriostatic circle experiment: referring to GB / T 38483-2020 Microbial Source Antibiotic Secondary Metabolite Anti-bacterial Activity Determination Bacteriostatic Circle Method, the Oxford cup method is used to determine the bacteriostatic circle diameters of cucumber fusarium wilt, tomato early blight and rice blast.

[0067] (2) Field test: carried out in a certain cucumber planting base, the test site is selected from a flat site with uniform fertility and consistent planting varieties, and is randomly divided into the embodiments 1-5 and comparative examples 1-2 groups, and the area of each plot is 30m 2The cucumber plants are uniformly sprayed by using a knapsack sprayer at a dose of 200 g / mu, and the spraying time is selected at 9-11 am on a windless day. The cucumber disease base is investigated before the pesticide application, and the disease index is investigated again after 15 days of the pesticide application, so as to calculate the relative control effect.

[0068] (3) Rainwater scouring resistance: the artificial rainfall device is used for testing, the simulated rainfall intensity is 10 mm / h, and the duration is 30 minutes. Before the rainfall, the nanocrystal bactericide is uniformly sprayed on the surface of the cucumber leaves, and the simulated rainfall is carried out after the pesticide is naturally dried. After the rainfall, the leaf samples are collected, the residual pesticide on the leaf surface is eluted by using a suitable solvent (for example, a mixed solution of ethanol-water mixed in a volume ratio of 1:1), the active ingredient content in the eluent is determined by HPLC, the leaf surface residual rate is calculated, and the rainwater scouring resistance of the bactericide is reflected.

[0069] Table 1 Performance test results of the broad-spectrum bactericide containing natural plant extracts

[0070] As shown in Table 1, the broad-spectrum bactericide containing natural plant extracts related to the embodiments of the present application has better bactericidal effect than the comparative product, has better control effect on the diseases and pests, and has better rainwater scouring resistance; the combination of the plant extract compound nanocrystal, the surface modification, the pine needles and the artemisia vulgaris is beneficial to improving the above performances.

[0071] The above embodiments are only for describing the technical concept and characteristics of the present application, the purpose is to enable the person skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application, and any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. A broad spectrum germicide containing natural plant extract, characterized in that, Each raw material is composed of the following components by weight parts: plant extract compound nanocrystals 20-30 parts, nanocrystal stabilizer 4-6 parts, cosolvent 15-25 parts, deionized water 50-60 parts.

2. The broad spectrum germicide containing natural plant extract according to claim 1, characterized in that, The cosolvent is ethanol; the nanocrystal stabilizer is a mixture of chitosan, other plant polysaccharides, and lecithin in a mass ratio of (1-2):(1-2):(0.5-1).

3. The broad spectrum germicide containing natural plant extract as claimed in claim 1, wherein, The degree of deacetylation of the chitosan is greater than or equal to 90%, and the weight average molecular weight is 10-20 kDa; the other plant polysaccharides are at least one of ginkgo leaf polysaccharides, seaweed polysaccharides, porphyra polysaccharides, and ganoderma lucidum polysaccharides.

4. The broad spectrum germicide containing natural plant extract according to claim 1, characterized in that, The preparation method of the plant extract compound nanocrystals comprises the following steps: Step S1, extraction of plant extract compound: mixing plant raw materials to obtain a mixture, adding citric acid buffer with pH = 4.5 and a complex enzyme, enzymatic hydrolysis for 2-4 hours, centrifugation for 15-25 minutes, collecting the supernatant; adding ethanol to extract the precipitate; combining the supernatant and the ethanol extract, and then centrifuging to obtain a crude extract solution; filtering the solution through a 0.25 μm filter, and then concentrating under reduced pressure to a relative density of 1.15 at 25°C to obtain a crude extract concentrate; Step S2, preparation of plant extract compound nanocrystals: uniformly dispersing the crude extract concentrate prepared in step S1 in a mixed solvent, adding lecithin, and ultrasonically treating for 13-18 minutes to obtain an oil phase; mixing a chitosan solution and a trehalose solution, and purging with nitrogen for 8-12 minutes to remove dissolved oxygen to obtain an aqueous phase; under the condition of constant temperature 25°C and mechanical stirring, the oil phase is added dropwise into the aqueous phase at a speed of 2 mL / min, and after the addition is completed, the stirring is continued for 25-35 minutes to form a primary nanocrystal suspension; the primary suspension is treated with a high-pressure homogenizer at 100-130 MPa for 5-8 cycles, and then filtered through a 0.22 μm filter to obtain a nanocrystal suspension; Step S3, surface modification: slowly adding an ethanol solution of trimethoxysilane into the nanocrystal suspension at 48-52°C under nitrogen protection, while maintaining the pH at 8.0-8.5 with ammonia water, and continuing the reaction for 1-2 hours after the addition is completed; centrifuging and freeze-drying to obtain plant extract compound nanocrystals.

5. The broad spectrum germicide containing natural plant extract as claimed in claim 4, wherein, The plant raw materials in step S1 include the following components by weight parts: Coptis 8-10 parts, Phellodendron 6-8 parts, Rheum 2-4 parts, Scutellaria 1-3 parts, Honeysuckle 3-5 parts, Mentha 1-2 parts, Sophora 4-6 parts, Ginkgo leaves 3-5 parts, Rosemary 2-4 parts, Garlic 1-3 parts, Pine needles 2-4 parts, Eucommia 2-4 parts, Artemisia annua 1-3 parts.

6. The broad spectrum germicide containing natural plant extract as claimed in claim 4, wherein, The mass ratio of the mixture, citric acid buffer, and complex enzyme in step S1 is 1:9:(0.03-0.05); the complex enzyme in step S1 is a mixture of cellulase EC 3.2.1.4 and pectinase EC 3.2.1.15 in a mass ratio of (1-2):

1. ​ 7. The broad spectrum germicide containing natural plant extract as claimed in claim 4, wherein, The mass ratio of the precipitate to ethanol in step S1 is 1: (6-10) ; the ethanol extraction in step S1 is heating reflux extraction, and the extraction is performed twice, each for 1-2 hours, and the two extraction solutions are combined; the mixed solvent in step S2 is prepared by mixing ethyl acetate and ethanol at a volume ratio of 3:1; and the mass ratio of the concentrated crude extract, the mixed solvent and lecithin in step S2 is (25-30) : 100: 0.

5.

8. The broad spectrum germicide containing natural plant extract as claimed in claim 4, wherein, The preparation method of the chitosan solution in step S2 comprises the following steps: dissolving chitosan in an acetic acid aqueous solution, magnetically stirring until completely dissolved, and then adjusting the pH to 5.5±0.1 by using a 1 mol / L NaOH solution; the mass ratio of the chitosan to the acetic acid aqueous solution is (1-2) g / 100 mL; the volume percentage concentration of the acetic acid aqueous solution is 0.5%; the mass ratio of trehalose to water in the trehalose solution in step S2 is (4-5) g / 50 mL; and the mass ratio of chitosan to trehalose in the aqueous phase in step S2 is 0.3:1; the volume ratio of the aqueous phase to the oil phase in step S2 is 5:

1.

9. The broad spectrum germicide containing natural plant extracts as claimed in claim 4, wherein, The volume ratio of trimethoxysilane to ethanol in the trimethoxysilane ethanol solution in step S3 is 1: (8-10) ; and the mass ratio of the trimethoxysilane ethanol solution to the nanocrystal suspension in step S3 is (0.4-0.6) :

100.

10. A process for the preparation of a broad spectrum germicide containing natural plant extract as claimed in any one of claims 1 to 9, wherein, The method comprises the following steps: mixing the raw materials according to the weight parts, sterilizing, and preparing a broad-spectrum bactericide containing natural plant extracts.

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