Plant effective components extracted in high gravity field environment and insect-proof microsphere film prepared from plant effective components

Abstract

The invention belongs to the field of smoke storage and insect prevention, and particularly relates to an insect prevention microsphere film prepared by extracting plant effective components in a high gravity field environment. Tobacco leaves are easily damaged by stored tobacco pests in the storage and alcoholization processes, and research and development of safe and effective insect-proof products are very important. The method comprises the following steps: screening plants with insect-killing and insect-preventing effects, extracting effective components in the plants by using a distillation method, extracting distillation residues in a high-gravity field environment, and taking the extracted effective components as an insect-preventing agent; the polyvinyl alcohol drug-loaded microsphere film is prepared by taking cyclodextrin microspheres as a drug-loaded sustained release agent, taking polyvinyl alcohol as a main film-forming raw material, taking water as a solvent and adding a film-forming plasticizer and a flexibilizer. The raw materials are easy to obtain and biodegradable, environmental pollution is reduced, the stability of effective components of plants can be improved, the action time of the medicine is prolonged, and the utilization rate of the medicine is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of insect prevention, and in particular relates to a plant effective component extracted in a hypergravity field environment and an insect-proof microsphere film prepared using the same. Background Art

[0002] Tobacco leaves are extremely vulnerable to tobacco storage pests during storage and aging. There are more than 30 types of tobacco storage pests in my country, including tobacco beetles, tobacco powder borers, red flour beetles and large flour beetles, which are very serious. At present, many tobacco warehouses of China Tobacco Company still rely on chemical control methods to control pests. Chemical control in tobacco warehouses mainly adopts fumigation methods, but the agents used in fumigation are prone to cause poisoning of personnel, spontaneous combustion, and possible explosion accidents. The green control technologies that are widely promoted and applied, such as nitrogen-filled insecticide technology, still have rough technical parameters, large workload, and poor humidity control; while biological control technology, physical control technology, etc. are mostly still in the experimental stage, so it is very important to develop safe and effective insect control technologies and products.

[0003] Plants have insecticidal and insect repellent effects. Extraction of these plant components can also produce extracts that have good insect repellent and insecticidal effects. There are many methods for extracting active ingredients from plants, including solvent extraction, ultrasound-assisted extraction, microwave-assisted extraction, and so on. Hypergravity technology is a technical means to enhance the molecular mixing and mass transfer process. Hypergravity extraction is the extraction of active ingredients from plants in a hypergravity field environment. The hypergravity factor is the ratio of acceleration to gravitational acceleration. The larger the value, the more obvious the hypergravity phenomenon. Hypergravity extraction methods are rarely reported.

[0004] The preparation of insect-proof microsphere membrane requires the formation of microspheres first and then the formation of membrane. The prepared microsphere membrane needs to successfully load the drug ingredients. Cyclodextrin has an internal hydrophobic cavity and a hydrophilic outer surface. It can form a reversible inclusion complex with different hydrophobic molecules and slowly release the guest drug without changing the physical, chemical and biological properties of the drug. Natural polymers have the characteristics of wide sources, low cost and easy availability, and short degradation time. They can be used as effective drug delivery systems and film-forming matrices. Polyvinyl alcohol has good film-forming properties, high tensile strength and excellent flexibility. It can be prepared into composite materials with excellent performance by blending with other polymers.

[0005] The present invention uses cyclodextrin and polyvinyl alcohol as base materials, firstly distills plants with insecticidal and insect-proofing effects, then extracts residues in a hypergravity field environment, and uses the extracted effective ingredients as drug carriers to prepare a microsphere membrane system for tobacco insect control. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and provide a plant active ingredient extracted in a hypergravity field environment with simple process, low cost and environmental friendliness and an insect-proof microsphere film prepared therefrom.

[0007] Based on the above purpose, the present invention adopts the following technical solutions: A method for extracting effective components from plants in a hypergravity field environment, comprising screening plants with insecticidal and insect-proofing effects, adding water for steam distillation (preferably for 2-10 hours), and obtaining a distilled extract; extracting plant residues with methanol or ethanol solution at room temperature and pressure in a hypergravity environment with a hypergravity factor of 2-2000 (preferably for 30-180 minutes), collecting the filtrate and concentrating it to obtain a concentrated solution; The distilled extract and / or concentrated solution is the plant effective ingredient.

[0008] The methanol or ethanol solution refers to pure methanol, or ethanol, or a 20-80% methanol / ethanol aqueous solution.

[0009] Specifically, the plant can be selected from one or more of mugwort, camphor, mint, prickly ash, ailanthus, oleander and wolfsbane, with camphor, mint and mugwort being preferred.

[0010] The present invention provides a plant active ingredient extracted by the above method. When used, the plant active ingredient can be dissolved in an organic solvent for dilution, and the organic solvent includes one or more of methanol, acetone, ethanol (preferably ethanol), etc.

[0011] The present invention also provides the use of the above plant effective components as insect repellent or in the preparation of insect repellent microsphere film.

[0012] The present invention also provides an insect-proof microsphere film, which uses the plant active ingredients as insect-proof agents, cyclodextrin microspheres as drug-carrying sustained-release agents, polyvinyl alcohol as the main film-forming raw material, water as the solvent, and film-forming plasticizers and toughening agents are added. After uniform dispersion, the film is sprayed or coated, and air-dried to obtain the film. Alternatively, the plant active ingredient is used as an insect repellent, and cyclodextrin microspheres are used as drug-loaded sustained-release agents. The cyclodextrin microspheres are immersed in the plant active ingredient for impregnation loading to obtain cyclodextrin drug-loaded microspheres; then polyvinyl alcohol is used as the main film-forming raw material, water is used as the solvent, a film-forming plasticizer and a toughening agent are added, and after uniform dispersion, the film is sprayed or coated, and air-dried to obtain the obtained microspheres; Alternatively, cyclodextrin microspheres are used as drug-carrying sustained-release agents, polyvinyl alcohol is used as the main film-forming raw material, water is used as the solvent, a film-forming plasticizer and a toughening agent are added, and after uniform dispersion, the film is sprayed or coated, air-dried, and then the plant active ingredients are sprayed on the film.

[0013] The present invention also provides an insect-proof microsphere film, which uses epichlorohydrin as a cross-linking agent, dissolves plant active ingredients and cyclodextrin in alkali solution, and reacts at room temperature to form an aqueous phase, and then drips the aqueous phase into the oil phase, stirs to obtain an oil-water mixed emulsion, reacts at a constant temperature for a certain time (preferably 60-80°C for 4-8h), stands, pours out the oil phase, centrifuges, washes, and air-dries to obtain cyclodextrin drug-loaded microspheres, and then uses polyvinyl alcohol as a main film-forming raw material, water as a solvent, adds a film-forming plasticizer and a toughening agent, disperses evenly, sprays or coats to form a film, and air-dries to obtain the microspheres.

[0014] In the above-mentioned insect-proof microsphere film, specifically, the film-forming plasticizer can be a biopolysaccharide, the toughening agent can be glycerol, and the biopolysaccharide can be one or more of sodium alginate, chitosan, starch, cellulose, etc. The mass ratio of polyvinyl alcohol to the film-forming plasticizer biopolysaccharide and the toughening agent glycerol can be 1:0.2-0.6:2. Polyvinyl alcohol, the film-forming plasticizer and the toughening agent are added to water to prepare a film liquid, and the amount of cyclodextrin microspheres or cyclodextrin drug-loaded microspheres added can be 10-30% of the mass of the film liquid.

[0015] Furthermore, the cyclodextrin microspheres are prepared by inverse emulsion polymerization, and can be prepared by the following method: using epichlorohydrin as a crosslinking agent, dissolving cyclodextrin in an alkali solution to form a water phase by crosslinking reaction at room temperature, adding the water phase dropwise to the oil phase, stirring at high speed to obtain an oil-water mixed emulsion, reacting at a constant temperature for a certain period of time, standing, pouring out the oil phase, centrifuging, washing, and drying to obtain the microspheres; The oil phase may be an oil solution containing surfactants such as Tween and Span, and the oil solution may be one of white oil, silicone oil, kerosene, etc. Further, the alkali may be one of sodium hydroxide, potassium hydroxide, etc.

[0016] Furthermore, the cyclodextrin may be one of α-, β-, and γ-cyclodextrin, with β- and γ-cyclodextrin being preferred.

[0017] Furthermore, the drug-loaded microspheres can be prepared by immersing the cyclodextrin microspheres in a plant extract solution for loading; or the plant extract, cyclodextrin, and a cross-linking agent can be prepared into an aqueous phase in an alkaline solution, and the drug-loaded microspheres can be obtained by reverse emulsion polymerization.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention extracts plant active ingredients under a hypergravity field environment, and uses the plant active ingredients as insect repellents to prepare drug-loaded insect repellent microsphere membranes. The insect repellent microsphere membranes of the present invention can improve the stability of plant active ingredients, prolong the drug action time, and the raw materials are easily available. The drugs loaded in the membranes can be gradually released as the membranes degrade, which can reduce environmental pollution and improve drug utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FTIR images of β-cyclodextrin microspheres and β-cyclodextrin prepared in Example 1; Figure 2 The optical microscope image (left) and SEM image (right) of the β-cyclodextrin microspheres prepared in Example 3; Figure 3 Optical microscope image (left) and SEM image (right) of the drug-loaded β-cyclodextrin microspheres / polyvinyl alcohol film prepared in Example 2. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described in detail below in conjunction with the embodiments, but the protection scope of the present invention is not limited thereto.

[0021] In the following examples, unless otherwise specified, the raw materials used are common commercial products that can be directly purchased or can be prepared by conventional methods in the art.

[0022] Room temperature refers to 25±5°C.

[0023] Methanol or ethanol refers to volume percentage unless otherwise specified.

[0024] The invention provides a method for preparing a drug-loaded microsphere membrane, wherein the cyclodextrin microsphere is prepared by using an inverse emulsion polymerization method.

[0025] Embodiment 1: The method for extracting plant active ingredients in a hypergravity field environment to prepare insect-proof microsphere membranes comprises the following steps: Preferably, 5 g of β-cyclodextrin and 3 g of NaOH are dissolved in 10 g of deionized water, 6.5 mL of epichlorohydrin is added, and the cross-linking reaction is carried out at room temperature for 2 h to form an aqueous phase.

[0026] Span80: Tween80 = 70:30 (mass ratio, 1.6 g), Span80 was added and preheated in a 55°C water bath for 15 min, Tween80 was added and stirred at 1000 r / min for 25 min, then 60 g kerosene was added and stirring was continued for 15 min to form an oil phase.

[0027] The aqueous phase was slowly added dropwise to the oil phase, and a high-speed stirrer was used to stir for 10 minutes to obtain an oil-water mixed emulsion, and then a magnetic stirrer was used to react at 600 rpm and a constant temperature of 65°C for 6 hours. After the reaction was completed, obvious stratification appeared after standing for 10 minutes, the oil phase was poured out, and the centrifuge was centrifuged at 9000 rpm for 5 minutes. The product was first neutralized to neutrality with 0.5M dilute hydrochloric acid, and then washed with acetone, anhydrous ethanol, and deionized water in sequence, and dried naturally at room temperature to obtain β-cyclodextrin microspheres synthesized by inverse emulsion polymerization.

[0028] First, 100g of camphor leaves were added with excess water for steam distillation extraction for 2h, and then separated for 2h to obtain an oily distillation extract. Then, the camphor leaf residue after distillation extraction was placed in 500mL of 60% ethanol water solvent, and extracted for 60min at room temperature and pressure in a hypergravity environment with a hypergravity factor of 12. The filtrate was collected and concentrated to a paste, and the concentrated paste and distillation extract were the plant active ingredients.

[0029] 0.5 g of the plant active ingredient was dissolved in 50 mL of 20% methanol solution for dilution, and 1 g of β-cyclodextrin microspheres was directly immersed in the above-obtained plant active ingredient at room temperature for 2 to 4 h for drug loading to obtain β-cyclodextrin drug-loaded microspheres.

[0030] 1 g of polyvinyl alcohol, 0.3 g of sodium alginate and 2 g of glycerol were added to 30 mL of deionized water in sequence, heated at 96 °C for 2 h and stirred to prepare a membrane liquid. β-cyclodextrin drug-loaded microspheres accounting for 15% of the membrane liquid mass were evenly dispersed in 30 g of the membrane liquid by ultrasound, coated on a polyethylene film by blade coating, and naturally air-dried to obtain a polyvinyl alcohol insect-repellent drug-loaded microsphere film.

[0031] Figure 1 The FTIR graphs of β-cyclodextrin microspheres and β-cyclodextrin prepared in Example 1 are given. The two lines in the figure represent the FTIR test curves of β-cyclodextrin microspheres and β-cyclodextrin, respectively. The two lines are at 3417 cm -1 and 3399cm -1 There are absorption peaks of -OH at 3417cm -1 The peak area at 2926cm decreased, proving that β-cyclodextrin reacted with the cross-linking agent. -1 and 2922cm -1 The peak at 800-1300cm is the stretching vibration peak of methylene -CH2. The absorption peak of β-cyclodextrin polymer microspheres is wider than that of β-cyclodextrin, which indicates that the β-cyclodextrin molecules and the cross-linking agent undergo a cross-linking reaction, resulting in an increase in the methylene content. -1 The absorption peak at the position is the characteristic absorption peak of the ether bond, and the absorption peak area of ​​the β-cyclodextrin polymer microspheres at this position is relatively wide, which further proves that a cross-linking reaction occurs between β-cyclodextrin and the cross-linking agent. Embodiment 2: The method for extracting plant active ingredients in a hypergravity field environment to prepare insect-proof microsphere membranes comprises the following steps: First, 150g of peppermint stems and leaves were added with excess water for steam distillation extraction for 3h, and then allowed to stand for separation for 2h to obtain an oily distillation extract. Then, the peppermint stem and leaf residues after distillation extraction were placed in 500 mL of ethanol solvent, and extracted for 40min at room temperature and pressure in a hypergravity environment with a hypergravity factor of 280, and the filtrate was collected and concentrated to a paste. The concentrated paste and the distillation extract were the active ingredients of the plant.

[0032] Take 0.1 g of plant active ingredients, 5 g of β-cyclodextrin, and 3 g of KOH, add them to 10 mL of water, and then add 6.5 mL of epichlorohydrin. The cross-linking reaction time is 1.5 h at room temperature to form an aqueous phase.

[0033] Span60: Tween60 = 76:27 (mass ratio, 1.6 g), Span60 was added and preheated in a 55°C water bath for 15 min, Tween60 was added and stirred at 2000 r / min for 15 min, then 60 g silicone oil was added and stirring was continued for 15 min to form an oil phase.

[0034] The aqueous phase was slowly added dropwise to the oil phase, and a high-speed stirrer was used to stir for 10 minutes to obtain an oil-water mixed emulsion, and then a magnetic stirrer was used at 800 rpm and a constant temperature of 70°C was used for reaction for 6 hours. After the reaction was completed, obvious stratification appeared after standing for 10 minutes, the oil phase was poured out, and the centrifuge was centrifuged at 9000 rpm for 5 minutes. The product was first neutralized to neutrality with 0.5M dilute hydrochloric acid, and then washed with acetone, anhydrous ethanol, and deionized water in sequence, and naturally air-dried at room temperature to obtain β-cyclodextrin drug-loaded microspheres formed by inverse emulsion polymerization.

[0035] 1 g of polyvinyl alcohol, 0.3 g of chitosan and 2 g of glycerol were added to 30 mL of deionized water in sequence, heated at 96 °C for 2 h and stirred to prepare a membrane liquid. Ultrasound was used to evenly disperse β-cyclodextrin drug-loaded microspheres accounting for 25% of the membrane liquid mass in 30 g of the membrane liquid. The film was formed by spraying and naturally air-dried to obtain a polyvinyl alcohol insect-repellent drug-loaded microsphere film. Embodiment 3: The method for extracting plant active ingredients in a hypergravity field environment to prepare insect-proof microsphere membranes comprises the following steps: Take 5 g of γ-cyclodextrin and 3 g of NaOH and dissolve them in 10 mL of deionized water. Then add 6.5 mL of epichlorohydrin and perform cross-linking reaction at room temperature for 2.5 h to form an aqueous phase.

[0036] Span40: Tween40 = 82:7 (mass ratio, 1.6 g), Span40 was added and preheated in a 60°C water bath for 15 min, Tween40 was added and stirred at 1500 r / min for 20 min, then 60 g of white oil was added and stirring was continued for 20 min to form an oil phase.

[0037] The aqueous phase was slowly added dropwise to the oil phase, and a high-speed stirrer was used to stir for 10 minutes to obtain an oil-water mixed emulsion, and then a magnetic stirrer was used to react at a constant temperature of 70°C at 1000rpm for 6 hours. After the reaction was completed, obvious stratification appeared after standing for 10 minutes, the oil phase was poured out, and the centrifuge was centrifuged at 9000rpm for 5 minutes. The product was first neutralized to neutrality with 0.5M dilute hydrochloric acid, and then washed with acetone, anhydrous ethanol, and deionized water in sequence, and dried naturally at room temperature to obtain γ-cyclodextrin microspheres formed by inverse emulsion polymerization.

[0038] First, add excess water to 200g of Artemisia argyi stems and leaves for steam distillation extraction for 3h, and stand for separation for 2h to obtain an oily distillation extract. Then place the distilled Artemisia argyi stem and leaf residue in 600mL of 60% methanol water solvent, extract for 30min at room temperature and pressure in a hypergravity environment with a hypergravity factor of 1000, collect the filtrate, and concentrate the filtrate to a paste. The concentrated paste and the distillation extract are the active ingredients of the plant.

[0039] 1g polyvinyl alcohol, 0.5g starch, and 2g glycerol were added to 30mL deionized water, heated at 96℃ for 2h and stirred to prepare a membrane solution, and γ-cyclodextrin microspheres accounting for 20% of the mass of the membrane solution were evenly dispersed in 30g of the membrane solution by ultrasound, and the membrane was formed by spraying and naturally air-dried to obtain a polyvinyl alcohol microsphere film. The plant active ingredients were sprayed on the polyvinyl alcohol microsphere film to form a polyvinyl alcohol insect repellent drug-loaded microsphere film.

[0040] Figure 2 The optical microscope image (left) and SEM image (right) of the β-cyclodextrin microspheres prepared in Example 3 are given; Figure 3 The optical microscope image (left) and SEM image (right) of the drug-loaded β-cyclodextrin microspheres / polyvinyl alcohol film prepared in Example 2 are shown. It can be seen from the figure that the prepared β-cyclodextrin microspheres have good sphericity, and similarly, the cyclodextrin microspheres loaded on the polyvinyl alcohol composite film can maintain a good spherical state; however, due to the loss of water in the product after natural air drying, the balls stick to each other, resulting in irregular protrusions on the surface of the balls.

[0041] Insect repellent effect test 500g of camphor leaves were used as raw materials. Excess water was first added for steam distillation extraction for 6h, and then separated for 2h to obtain an oily distillation extract. The camphor leaf residue after distillation was then placed in 1500mL of 20% ethanol solvent and extracted for 40min in an environment with a supergravity factor of 1000. The filtrate was collected and concentrated to a paste. The concentrated paste was combined with the distillation extract to obtain the plant active ingredient. 100μL of the extract was placed in a glass culture dish and 10 adults of Tribolium castaneum were inoculated. All of them died after 30min.

[0042] 0.5g of plant active ingredients was dissolved in 50mL of 20% methanol solution for dilution, and 2mL of the diluted plant active ingredients was sprayed on the 30g polyvinyl alcohol microsphere film prepared in Example 3 to form a polyvinyl alcohol insect-proof drug-loaded microsphere film. The polyvinyl alcohol insect-proof drug-loaded microsphere film was placed in a glass culture dish as the only food source, and 10 adults of red flour beetles were accessed. The number of dead insects was checked after 24h, 48h, and 72h, and the mortality rate was calculated. It was determined that all adults were dead when detected after 24h.

[0043] The embodiments described above are merely descriptions of preferred implementations of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for extracting active ingredients from plants in a hypergravity field environment, characterized in that: Screening plants with insecticidal and insect-proofing effects, adding water to perform steam distillation to obtain a distillation extract; extracting plant residues with methanol or ethanol solution under a hypergravity environment with a hypergravity factor of 2 to 2000 at normal temperature and pressure, collecting the filtrate and concentrating it to obtain a concentrate; The distilled extract and / or concentrated solution is the plant effective ingredient.

2. The method for extracting active ingredients from plants in a hypergravity field environment as claimed in claim 1, characterized in that: The plant is selected from one or more of mugwort, camphor, mint, prickly ash, ailanthus altissima, oleander and wolfsbane.

3. The plant active ingredients obtained by extraction using the method described in any one of claims 1 or 2.

4. Use of the plant active ingredient according to claim 3 as an insect repellent or in the preparation of insect repellent microsphere film.

5. An insect-proof microsphere film, characterized in that: The plant active ingredient of claim 3 is used as an insect repellent, cyclodextrin microspheres are used as a drug-carrying sustained-release agent, polyvinyl alcohol is used as a main film-forming raw material, water is used as a solvent, a film-forming plasticizer and a toughening agent are added, and after being evenly dispersed, the film is sprayed or coated, and air-dried to obtain the product; Alternatively, the plant active ingredient of claim 3 is used as an insect repellent, and cyclodextrin microspheres are used as drug-carrying sustained-release agents. The cyclodextrin microspheres are immersed in the plant active ingredient for impregnation loading, and then polyvinyl alcohol is used as the main film-forming raw material, water is used as the solvent, a film-forming plasticizer and a toughening agent are added, and after uniform dispersion, the film is sprayed or coated, and air-dried to obtain the product; Alternatively, cyclodextrin microspheres are used as drug-carrying sustained-release agents, polyvinyl alcohol is used as the main film-forming raw material, water is used as the solvent, a film-forming plasticizer and a toughening agent are added, and after uniform dispersion, the film is sprayed or coated, air-dried, and then the plant active ingredient described in claim 3 is sprayed on the film.

6. An insect-proof microsphere film, characterized in that: With epichlorohydrin as a cross-linking agent, the plant active ingredients and cyclodextrin are dissolved in alkaline solution and cross-linked at room temperature to form an aqueous phase, the aqueous phase is added dropwise to the oil phase, stirred to obtain an oil-water mixed emulsion, reacted at a constant temperature for a certain period of time, allowed to stand, the oil phase poured out, centrifuged, washed, and dried to obtain drug-loaded microspheres, and then polyvinyl alcohol is used as the main film-forming raw material, water is used as a solvent, a film-forming plasticizer and a toughening agent are added, and after uniform dispersion, the film is sprayed or coated, and air-dried to obtain the microspheres.

7. The insect-proof microsphere film according to claim 5 or 6, characterized in that: The film-forming plasticizer is biopolysaccharide, the toughening agent is glycerol, and the biopolysaccharide is one or more of sodium alginate, chitosan, starch, and cellulose.

8. The insect-proof microsphere film according to claim 5, characterized in that: The cyclodextrin microspheres are prepared by the following method: using epichlorohydrin as a crosslinking agent, dissolving cyclodextrin in an alkaline solution and reacting at room temperature to form an aqueous phase, dropping the aqueous phase into the oil phase, stirring to obtain an oil-water mixed emulsion, reacting at a constant temperature for a certain period of time, standing, pouring out the oil phase, centrifuging, washing, and drying to obtain the microspheres; The oil phase is an oil solution containing surfactants such as Tween and Span, and the oil solution is one of white oil, silicone oil and kerosene.

9. The insect-proof microsphere film according to claim 6, characterized in that: The cyclodextrin is one of α-, β-, and γ-cyclodextrin.

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