Application of carboxylic ester compound as insecticidal synergist and method

Abstract

The invention belongs to the technical field of pest control, and relates to application of a carboxylic ester compound as a prodenia litura insecticidal synergist and a method. The carboxylic ester compound is ethyl 2-({[2-(4-ethyoxyl phenyl)-4-quinolyl] carbonyl} amino)-5, 6, 7, 8-tetrahydro-4H-cycloheptane [b] thiophene-3-carboxylic ester, and the structural formula of the carboxylic ester compound is shown in the specification. The carboxylic ester compound is used for inhibiting prodenia litura cytochrome p450 enzyme; the prodenia litura cytochrome p450 enzyme is a CYP6AE48 enzyme, and the prodenia litura cytochrome p450 The compound can well inhibit the activity of a prodenia litura CYP6AE48 enzyme, so that the prodenia litura CYP6AE48 enzyme cannot normally play a role in detoxifying lambda-cyhalothrin, the control effect of lambda-cyhalothrin is further improved, and the compound can be used as a pesticide synergist to play a synergistic role in pest control.

Description

Technical Field

[0001] The invention belongs to the technical field of pest control, and particularly relates to the use and method of a carboxylic acid ester compound as a synergist for killing Spodoptera litura. Background Art

[0002] Spodoptera litura ( Spodoptera litura Fabricius) belongs to the Noctuidae family of Lepidoptera and is a worldwide agricultural pest. It has a wide range of food habits, and its host plants are in a total of 109 families. It mainly damages cotton, tobacco, sugar beet, tomato, pepper, peanut and cruciferous vegetables, etc. Spodoptera litura is a kind of omnivorous and voracious pest. The larvae feed on leaves, flower buds, flowers, etc. It can occur in multiple generations in a year, lays eggs concentratedly and in large quantities, and the larvae damage the whole plant, feeding on various tissues and organs of the host. The crops are severely damaged by it, causing huge economic losses to agricultural production.

[0003] At present, chemical pesticides are mainly used to control field pests. This method is simple and convenient, can quickly reduce the pest population density, is suitable for large-area farmland management, and can avoid serious losses of crops in the short term. However, long-term and repeated use is likely to cause gene mutations in pests and a significant increase in drug resistance. The resistance of Spodoptera litura to insecticides develops very fast. For example, it has developed different levels of resistance to multiple insecticides such as cyantraniliprole, cypermethrin, abamectin, etc. Therefore, there is an urgent need for a synergist for killing insects to improve the control effect of chemical agents.

[0004] The insect cytochrome P450 enzyme system (Cytochrome P450 monooxygenase, abbreviated as P450 enzyme) belongs to the monooxygenase class and can participate in the metabolism and detoxification of exogenous substances (such as insecticides, plant secondary metabolites, etc.), and also participates in the synthesis and metabolism of insect endogenous substances. Piperonyl butoxide (synergistic ether) is the most widely used P450 enzyme inhibitor, and it has been on the market as a pesticide synergist for many years. Synergistic ether is a semi-natural compound simply synthesized from safrole, which can inhibit a variety of P450 enzymes related to biosynthesis reactions, thereby improving the insecticidal activity of a variety of insecticides, but its effect on P450 enzymes related to detoxification metabolism is not obvious. And many studies have shown that the main reason for the resistance and cross-resistance of most pests to insecticides is the enhanced action of P450 enzymes related to detoxification metabolism.

[0005] Therefore, developing P450 enzyme inhibitors related to detoxification metabolism is expected to play a synergistic role as pesticide synergists in pest control. Summary of the Invention

[0006] In order to enrich the types of existing pesticide synergists and further enhance the pest control effect, the present invention takes the Spodoptera litura CYP6AE48 enzyme (a P450 enzyme related to detoxification metabolism) as the main target, screens a carboxylic acid ester compound, and proves that this compound has an enhancing or promoting effect on the control effect of lambda-cyhalothrin, and is better than the commonly used piperonyl butoxide as a synergist in the market in improving the effect of lambda-cyhalothrin.

[0007] In order to achieve the above technical purpose, the present invention provides the following technical solutions: Use of a carboxylic acid ester compound as a pesticide synergist, wherein the carboxylic acid ester compound is ethyl 2-({[2-(4-ethoxyphenyl)-4-quinolyl]carbonyl}amino)-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carboxylate; the structural formula of the carboxylic acid ester compound is as follows: 。

[0008] Further, the carboxylic acid ester compound inhibits the cytochrome p450 enzyme of Spodoptera litura.

[0009] Further, the cytochrome p450 enzyme of Spodoptera litura is CYP6AE48 enzyme.

[0010] A method for improving the chemical control effect of Spodoptera litura, the method comprising: using the carboxylic acid ester compound as an inhibitor of the cytochrome p450 enzyme of Spodoptera litura and acting on Spodoptera litura to improve the chemical control effect of Spodoptera litura; The carboxylic acid ester compound is ethyl 2-({[2-(4-ethoxyphenyl)-4-quinolyl]carbonyl}amino)-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carboxylate.

[0011] Further, the cytochrome p450 enzyme of Spodoptera litura is CYP6AE48 enzyme.

[0012] Further, the carboxylic acid ester compound is dissolved in dimethyl sulfoxide to prepare a solution with a concentration of 8-10 g / L, and the usage amount of the solution is 16-20 μg / head.

[0013] Further, the chemical control is carried out using lambda-cyhalothrin.

[0014] Further, the carboxylic acid ester compound makes the control effect of lambda-cyhalothrin against Spodoptera litura increase by 10.22, 10.02, and 20.14 times at 24, 48, and 72 h respectively.

[0015] The beneficial effects of the present invention are: The present invention takes the CYP6AE48 enzyme of Spodoptera litura as the main target, and a carboxylic acid ester compound is screened out, which is ethyl 2-({[2-(4-ethoxyphenyl)-4-quinolyl]carbonyl}amino)-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carboxylate. Specifically, at 24, 48, and 72 h, the effect of lambda-cyhalothrin in controlling Spodoptera litura was increased by 10.22, 10.02, and 20.14 times respectively by this compound. This compound can better inhibit the activity of the CYP6AE48 enzyme of Spodoptera litura, making it unable to normally exert its detoxification function on lambda-cyhalothrin, thereby enhancing the control effect of lambda-cyhalothrin. This compound can be used as a pesticide synergist to play a synergistic role in pest control.

[0016] Existing P450 enzyme inhibitors (such as piperonyl butoxide) mainly inhibit P450 enzymes related to biosynthesis reactions, while P450 enzymes related to detoxification metabolism are the main reasons for the resistance and cross-resistance of most pests to pesticides, and are more important for pest control. The present invention takes the P450 enzyme CYP6AE48 related to the detoxification metabolism of Spodoptera litura as the target, and screens out a P450 enzyme inhibitor related to detoxification metabolism, making up for the technical defect of the relative lack of such enzyme inhibitors, which has important inspiring and guiding significance for the future research of pesticide synergists. Brief Description of the Drawings

[0017] Figure 1 It is a molecular docking result diagram of the CYP6AE48 enzyme and the carboxylic acid ester compound. Detailed Embodiments

[0018] The present invention will be described below in conjunction with embodiments. The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] The experimental methods in the following embodiments are all conventional methods unless otherwise specified, and are carried out according to the techniques or conditions described in the literature in this field or according to the product instructions. The materials, reagents, etc. used in the following embodiments can be obtained from commercial channels unless otherwise specified.

[0020] In the following embodiments, the carboxylic acid ester compound is: ethyl 2-({[2-(4-ethoxyphenyl)-4-quinolyl]carbonyl}amino)-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carboxylate (purity is 99%), and this compound is purchased from SPECS company. The structural formula of the carboxylic acid ester compound is as follows: 。

[0021] In the present invention, the Spodoptera litura larvae were independently cultured by the Laboratory of Environment-Friendly Pesticides of Sichuan Agricultural University.

[0022] Example 1: This example describes the killing effect of lambda-cyhalothrin alone on Spodoptera litura.

[0023] Test method: Weigh the lambda-cyhalothrin technical material, and prepare a 1 g / L mother liquor with acetone as the solvent. Then dilute it to 3, 2, 1.5, 1, 0.5 mg / L respectively to obtain the lambda-cyhalothrin solutions.

[0024] Using the 3rd instar larvae of Spodoptera litura as test insects, use a micro-drop applicator to drop the lambda-cyhalothrin solution on the pronotum of the larvae, 1 μL for each larva. After natural air drying, put them into an incubator. The temperature of the incubator is 27 ± 1 °C, the relative humidity is 70%, and the illumination duration is 12 h. Use acetone as the control group, and the other treatment steps are the same. Treat 20 larvae in each petri dish, repeat 3 times, observe the results at 24, 48, and 72 h respectively, record the number of dead insects. If the larvae do not wriggle when gently touched with a brush, it is regarded as dead. Use DPS 9.01 software to calculate the virulence regression equation, correlation coefficient, and LC 50 。

[0025] Test results: See Table 1; at 24, 48, and 72 h, when using lambda-cyhalothrin alone, the LC 50 values are 2.5252, 2.3204, and 2.0642 mg / L respectively.

[0026] Table 1. The usage effect of lambda-cyhalothrin alone Example 2: This example describes the usage effect of using the carboxylic ester compound as a synergist when using lambda-cyhalothrin.

[0027] Test method: Weigh the lambda-cyhalothrin technical material, and prepare a 1 g / L mother liquor with acetone as the solvent. Then dilute it to 0.5, 1, 1.5, 2, 3 mg / L to obtain the lambda-cyhalothrin solutions. Separately, use dimethyl sulfoxide as the solvent to prepare the carboxylic ester compound with a concentration of 8 - 10 g / L.

[0028] Using the 3rd instar larvae of Spodoptera litura as test insects, the solution of the carboxylic ester compound was dropped onto the prothoracic dorsum of the larvae with a microapplicator, 16 - 20 μg was dropped for each larva. After natural air drying for 1 h, the solution of lambda-cyhalothrin was dropped in the same method, 1 μl was dropped for each larva. After dropping, they were placed in an incubator, the temperature of the incubator was 27 ± 1°C, the relative humidity was 70%, and the illumination duration was 12 h. In the control group, dimethyl sulfoxide was used to replace the solution of the carboxylic ester compound, and the remaining treatment steps were the same. 20 larvae were treated in each petri dish, with 3 replicates. The results were observed at 24, 48, and 72 h respectively, the number of dead insects was recorded, and the larvae were regarded as dead if they did not wriggle when gently touched with a writing brush. The toxicity regression equation, correlation coefficient, and LC 50 were calculated using DPS 9.01 software, and the synergistic ratio (SR) was calculated.

[0029] Synergistic ratio (SR) = LC 50 when lambda-cyhalothrin was used alone / LC 50 of lambda-cyhalothrin when the carboxylic ester compound was used as a synergist 50 Test results: See Table 2; at 24, 48, and 72 h, when the carboxylic ester compound was used as a synergist with lambda-cyhalothrin, the LC 50 values were 0.2472, 0.2316, and 0.1025 mg / L respectively.

[0030] Table 2. Application effect of lambda-cyhalothrin when the carboxylic ester compound was used as a synergist As can be seen from Table 1 and Table 2, at 24, 48, and 72 h, the LC 50 values of lambda-cyhalothrin when the carboxylic ester compound was added were significantly lower than the LC 50 when lambda-cyhalothrin was used alone, indicating that the CYP6AE48 enzyme of Spodoptera litura was inhibited by the carboxylic ester compound and could not normally exert its detoxification function on lambda-cyhalothrin. Therefore, the effect of using lambda-cyhalothrin when the carboxylic ester compound was added was better, meeting the expectations. In addition, at 24, 48, and 72 h, the synergistic ratios were 10.22, 10.02, and 20.14 respectively, all greater than 1, indicating that the application effect of the carboxylic ester compound was good.

[0031] Example 3: This example describes the application effect of piperonyl butoxide as a synergist when using lambda-cyhalothrin.

[0032] Test method: Weigh the technical material of lambda-cyhalothrin, and prepare a mother liquor of 1 g / L with acetone as the solvent, and then dilute it to 0.5, 1, 1.5, 2, 3 mg / L to obtain the lambda-cyhalothrin solution. Separately, with dimethyl sulfoxide as the solvent, prepare a solution with the piperonyl butoxide concentration of 8 - 10 g / L.

[0033] Using the 3rd instar larvae of Spodoptera litura as test insects, piperonyl butoxide was pipetted onto the pronotum of the larvae with a micropipettor, 20 μg was pipetted for each larva. After natural air drying for 1 h, the lambda-cyhalothrin solution was pipetted in the same method, 1 μl was pipetted for each larva. After pipetting, they were placed into an incubator, the temperature of the incubator was 27±1 °C, the relative humidity was 70%, and the illumination duration was 12 h. In the control group, dimethyl sulfoxide was used to replace piperonyl butoxide, and the remaining treatment steps were the same. 20 were treated in each petri dish, with 3 replicates. The results were observed at 24, 48, and 72 h respectively, the number of dead insects was recorded, and the larvae were considered dead if they did not wriggle when gently touched with a writing brush. The DPS 9.01 software was used to calculate the toxicity regression equation, correlation coefficient, and LC 50 , and the synergistic ratio (SR) was calculated.

[0034] Synergistic ratio (SR) = LC 50 when lambda-cyhalothrin was used alone / LC 50 Test results: see Table 3; at 24, 48, and 72 h, when piperonyl butoxide was used as a synergist for lambda-cyhalothrin, the LC 50 values were 0.4997, 0.3782, and 0.2472 mg / L respectively.

[0035] Table 3. Application effect of lambda-cyhalothrin when piperonyl butoxide was used as a synergist It can be seen from Table 2 and Table 3 that at 24, 48, and 72 h, the LC 50 of lambda-cyhalothrin when piperonyl butoxide was added was higher than the LC 50 of lambda-cyhalothrin when carboxylic ester compounds were added, indicating that the effect was better when carboxylic ester compounds were used as synergists. It was calculated from Table 1 and Table 3 that at 24, 48, and 72 h, the synergistic ratios of lambda-cyhalothrin when piperonyl butoxide was added were 5.05, 6.13, and 9.10 respectively, which were all less than the synergistic ratios when carboxylic ester compounds were used as synergists, and this could also prove the above conclusion.

[0036] In summary, in the present invention, using the CYP6AE48 enzyme of Spodoptera litura as the main target, a carboxylic ester compound was screened, which was ethyl 2-({[2-(4-ethoxyphenyl)-4-quinolyl]carbonyl}amino)-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carboxylate.

[0037] The molecular docking results show that there are van der Waals forces, Sulfur-X (a polysulfide bond), Pi-Sulfur (the interaction between the π-electron cloud on the aromatic ring and the sulfur atom), Pi-Pi T-shaped (π-π stacking), Alkyl, and Pi-Alkyl (a non-bonding interaction) between the carboxylic ester compound and CYP6AE48 enzyme; as Figure 1 shown, Glycine (GLY) 258, Glycine (GLY) 262, Glutamic acid (GLU) 193, Threonine (THR) 206, Threonine (THR) 200, Asparagine (ASN) 203, and Phenylalanine (PHE) 205 in the enzyme bind to the compound through van der Waals forces. Phenylalanine (PHE) 208 in the enzyme binds to the compound through Sulfur-X (a polysulfide bond). Threonine (THR) 194 in the enzyme binds to the compound through Pi-Sulfur (the interaction between the π-electron cloud on the aromatic ring and the sulfur atom). Tryptophan (TRP) 195 in the enzyme binds to the compound through Pi-Pi T-shaped (π-π stacking). Phenylalanine (PHE) 251, Leucine (LEU) 255, and Valine (VAL) 192 in the enzyme bind to the compound through Alkyl. Lysine (LYS) 199, Proline (PRO) 207, Isoleucine (ILE) 259, and Arginine (ARG) 263 in the enzyme bind to the compound through Pi-Alkyl (a non-bonding interaction).

[0038] It is experimentally known that the compound has a good inhibitory effect on the CYP6AE48 enzyme of Spodoptera litura, preventing its degradation of lambda-cyhalothrin, and is expected to play a synergistic role as a pesticide synergist in pest control.

[0039] The above-described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art under the condition of the concept of the present invention through relevant deductions and substitutions without making creative efforts fall within the scope of protection of the present invention.

Claims

1. Use of a carboxylic acid ester compound as a pesticide synergist, characterized in that, The carboxylic acid ester compound is ethyl 2-({[2-(4-ethoxyphenyl)-4-quinolyl]carbonyl}amino)-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carboxylate; the structural formula of the carboxylic acid ester compound is as follows: 。 2. The use according to claim 1, characterized in that, The carboxylic acid ester compound inhibits the cytochrome p450 enzyme of Spodoptera litura.

3. The use according to claim 2, characterized in that, The cytochrome p450 enzyme of Spodoptera litura is CYP6AE48 enzyme.

4. A method for improving the chemical control effect of Spodoptera litura, characterized in that, The method includes: using the carboxylic acid ester compound as an inhibitor of the cytochrome p450 enzyme of Spodoptera litura and acting on Spodoptera litura to improve the chemical control effect of Spodoptera litura; The carboxylic acid ester compound is ethyl 2-({[2-(4-ethoxyphenyl)-4-quinolyl]carbonyl}amino)-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carboxylate.

5. The method according to claim 4, wherein The cytochrome p450 enzyme of Spodoptera litura is CYP6AE48 enzyme, and it has been found that this enzyme can decompose phytotoxins and environmental pollutants and reduce their toxicity.

6. The method according to claim 4, characterized in that The carboxylic acid ester compound is dissolved in dimethyl sulfoxide to prepare a solution with a concentration of 8 - 10 g / L, and the usage amount of the solution is 16 - 20 μg / head.

7. The method according to claim 4, wherein The chemical control is to use lambda-cyhalothrin for control.

8. The method according to claim 7, wherein The carboxylic acid ester compound makes the control effect of lambda-cyhalothrin against Spodoptera litura increase by 10.22, 10.02, and 20.14 times at 24, 48, and 72 h respectively.

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