Natural insecticidal active compound as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of natural products, and particularly relates to a natural insecticidal active compound as well as a preparation method and application thereof. The invention provides a natural insecticidal active compound which has a structure as shown in a formula 1. The natural insecticidal active compound provided by the invention shows remarkable insecticidal activity on myzus persicae and Armiges subbaldus, and a new direction is opened up for the research and development of an efficient and environment-friendly biological insecticide. The invention provides the preparation method of the natural insecticidal active compound with the structure as shown in the formula 1, the natural insecticidal active compound is obtained through polar solvent extraction, ethyl acetate extraction and column chromatography purification, and the preparation method provided by the invention is short in period, mild in condition, few in by-product, strong in stereoselectivity, low in cost and easy to realize industrialization.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of natural products, and particularly relates to a natural insecticidal active compound and a preparation method and application thereof. BACKGROUND

[0002] At present, chemical pesticides still play an important role in the control of agricultural pests and diseases. However, chemical pesticides also have the shortcomings of large use amount, easy resistance and serious environmental pollution, which limit the development of the chemical pesticide industry and agricultural production. Plant secondary metabolites can not only provide excellent lead compounds for the synthesis and screening of novel pesticide molecules, but also can be directly developed into environmentally friendly natural product pesticides, which can not only control pests and diseases, but also reduce the residues and pollution caused by the use of chemical pesticides, and has a positive significance for promoting the sustainable development of agriculture.

[0003] Chrysanthemum is a perennial herb of the genus Artemisia of the Asteraceae family, and is the natural source of pyrethrin. Chrysanthemum has been famous as a natural insecticide for a long time. Chrysanthemum extract is an active ingredient with insecticidal effect separated and extracted from the inflorescence of chrysanthemum, also known as natural pyrethrin. The effective components are composed of six components, namely pyrethrin I, pyrethrin II, cinerin I, cinerin II, jasmoline I and jasmoline II. Chrysanthemum extract has high insecticidal activity, wide insecticidal spectrum, good control effect on various sanitary pests, warehouse pests and agricultural pests, is easily decomposed in nature and has low residue, and is relatively safe to warm-blooded animals such as humans and livestock, so it has been widely concerned by countries around the world.

[0004] However, there is still a lack of reports on chrysanthemum extract with good killing effect on aphids and mosquitoes in the prior art. SUMMARY

[0005] The purpose of the present application is to provide a natural insecticidal active compound and a preparation method and application thereof. The natural insecticidal active compound provided by the present application shows significant insecticidal activity on Myzus persicae and Armigeres subalbatus, opens up a new direction for the research and development of high-efficiency and environmentally friendly biological insecticides, and improves the utilization rate of chrysanthemum resources.

[0006] In order to achieve the above purpose, the present application provides the following technical scheme:

[0007] The present application provides a natural insecticidal active compound having the structure shown in formula 1:

[0008]

[0009] The application provides a preparation method of the natural insecticidal active compound.

[0010] (1) extracting the chrysanthemum cinerariaefolium residue by using a polar solvent to obtain an extraction solution, and concentrating the extraction solution to obtain a total crude extract;

[0011] (2) dispersing the total crude extract in water, and extracting the obtained solution with ethyl acetate to obtain an ethyl acetate phase;

[0012] (3) concentrating the ethyl acetate phase to obtain a total ethyl acetate-soluble product;

[0013] (4) dissolving the total ethyl acetate-soluble product in a methanol-dichloromethane mixture, then mixing the product with silica gel, removing the solvent to obtain a dry mixture, and then performing normal phase column chromatography separation on the dry mixture, wherein the normal phase column chromatography separation is performed by gradient elution with a dichloromethane-methanol system with a volume ratio of dichloromethane to methanol being 1:0-0:1 from large to small in volume ratio, and the same fractions are combined to obtain nine fractions, which are named as Fr.A-Fr.I fractions, respectively;

[0014] (5) performing first chromatography separation on the Fr.D fraction, wherein the first chromatography separation is performed by gradient elution with a dichloromethane-methanol system with a volume ratio of dichloromethane to methanol being 100:0-3:1 from large to small in volume ratio, and the same fractions are combined to obtain four sub-fractions, which are named as Fr.1-Fr.4 sub-fractions, respectively;

[0015] (6) performing second chromatography separation on the Fr.2 sub-fraction, wherein the second chromatography separation is performed by gradient elution with a dichloromethane-methanol system with a volume ratio of dichloromethane to methanol being 100:0-5:1 from large to small in volume ratio, and the same fractions are combined to obtain the natural insecticidal active compound with the structure shown in formula 1.

[0016] Preferably, in step (1), the extraction is performed for 3-4 times, the temperature of each extraction is 50-55 DEG C, and the time of each extraction is 20-40 min.

[0017] Preferably, in step (1), the polar solvent is an ethanol aqueous solution, the volume percentage content of ethanol in the ethanol aqueous solution is 80-85 %, and the solid-liquid ratio of each extraction is (2-4) kg:10 L.

[0018] Preferably, in step (4), the volume ratio of methanol to dichloromethane in the methanol-dichloromethane mixture is 15-20:1.

[0019] Preferably, in step (4), the silica gel used in the normal phase column chromatography separation is 100-200 mesh silica gel.

[0020] The normal phase column chromatography separation is: sequentially using a dichloromethane-methanol system with a volume ratio of 1:0, 40:1, 20:1, 10:1, and 0:1 for gradient elution.

[0021] Preferably, in step (5), the first chromatographic separation is: sequentially using a dichloromethane-methanol system with a volume ratio of 100:0, 40:1, 20:1, 10:1, and 3:1 for gradient elution.

[0022] Preferably, in step (6), the second chromatographic separation is: sequentially using a dichloromethane-methanol system with a volume ratio of 100:0, 40:1, 20:1, 10:1, and 5:1 for gradient elution.

[0023] The application provides the application of the insecticidal active compound with the structure of formula 1 in an insecticide.

[0024] Preferably, the insecticide is an insecticide for killing aphids and / or mosquitoes.

[0025] The application provides a natural insecticidal active compound (pyrethrindreg II) with the structure shown in formula 1. The natural insecticidal active compound provided by the application contains a cyclopropane ring, a methoxy group, a hydroxyl group and other functional groups in the structure, forms a unique molecular skeleton, and shows significant insecticidal activity on Myzus persicae and Armigeres subalbatus, thereby opening up a new direction for developing high-efficiency and environmentally-friendly biological insecticides. The results of the examples show that the compound pyrethrindreg II provided by the application shows significant insecticidal activity on aphids and mosquitoes, and is of great significance for developing new biological insecticides. By using a standard insecticidal experiment method, the compound pyrethrindreg II shows significant insecticidal activity on aphids and mosquitoes, and the LC 50 values are 9.4914 mg / L and 0.5770 mg / L, respectively.

[0026] The application provides a preparation method of the natural insecticidal active compound. The compound pyrethrindreg II is a secondary metabolite of chrysanthemum cinerariaefolium, and is obtained through polar solvent extraction, ethyl acetate extraction and column chromatography purification. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The H-NMR spectrum of the compound pyrethrindreg II is shown in Figure 1. 1 H-NMR spectrum;

[0028] Figure 2 The C-NMR spectrum of the compound pyrethrindreg II is shown in Figure 2. 13 C-NMR spectrum;

[0029] Figure 3 The HMBC spectrum of the compound pyrethrindreg II is shown in Figure 3.

[0030] Figure 4 The HSQC spectrum of the compound pyrethrindreg II is shown in Figure 4.

[0031] Figure 5 The HRESI-MS spectrum of the compound pyrethrindreg II is shown in Figure 5. DETAILED DESCRIPTION

[0032] The application provides a natural insecticidal active compound, which has the structure shown in formula 1.

[0033]

[0034] The application provides a preparation method of the natural insecticidal active compound, and the preparation method comprises the following steps.

[0035] (1) polar solvent is used to extract chrysanthemum cinerariaefolium residues to obtain an extraction solution, and the extraction solution is concentrated to obtain a total crude extract;

[0036] (2) dispersing the total crude extract in water, and extracting the obtained solution with ethyl acetate to obtain an ethyl acetate phase;

[0037] (3) concentrating the ethyl acetate phase to obtain a total ethyl acetate soluble product;

[0038] (4) dissolving the total ethyl acetate soluble product in a methanol-dichloromethane mixture, then mixing with silica gel, removing the solvent to obtain a dry mixture, and then loading the dry mixture into a column for normal phase column chromatography separation, wherein the normal phase column chromatography separation is performed by gradient elution using a dichloromethane-methanol system with a volume ratio of dichloromethane to methanol being 1:0 to 0:1 from large to small in volume ratio, and the same fractions are combined to obtain nine fractions, which are named as Fr.A to Fr.I fractions, respectively;

[0039] (5) performing first chromatography separation on the Fr.D fraction, wherein the first chromatography separation is performed by gradient elution using a dichloromethane-methanol system with a volume ratio of dichloromethane to methanol being 100:0 to 3:1 from large to small in volume ratio, and the same fractions are combined to obtain four sub-fractions, which are named as Fr.1 to Fr.4 sub-fractions, respectively;

[0040] (6) performing second chromatography separation on the Fr.2 sub-fraction, wherein the second chromatography separation is performed by gradient elution using a dichloromethane-methanol system with a volume ratio of dichloromethane to methanol being 100:0 to 5:1 from large to small in volume ratio, and the same fractions are combined to obtain a natural insecticidal active compound with a structure shown in Formula 1.

[0041] In the present application, all the preparation raw materials / components are commercially available products well known to those skilled in the art, unless otherwise specified.

[0042] In the present application, the Chrysanthemum cinerariaefolium residue is extracted by a polar solvent to obtain an extraction liquid, and the extraction liquid is concentrated to obtain a total crude extract.

[0043] In the embodiments of the present application, the Chrysanthemum cinerariaefolium residue is preferably a residue remaining after supercritical carbon dioxide extraction of essential oil from Chrysanthemum cinerariaefolium dry flowers.

[0044] In the specific embodiments of the present application, the preparation method of the Chrysanthemum cinerariaefolium residue preferably comprises: firstly, subjecting the Chrysanthemum cinerariaefolium dried flowers to supercritical CO2 extraction, and taking away the essential oil in the Chrysanthemum cinerariaefolium dried flowers, and the residue obtained by the supercritical CO2 extraction is dried to obtain the Chrysanthemum cinerariaefolium residue. In the present application, the Chrysanthemum cinerariaefolium dried flowers are obtained by drying the Chrysanthemum cinerariaefolium fresh flowers. The supercritical CO2 extraction is preferably carried out in a supercritical CO2 extraction kettle. The pressure of the supercritical CO2 extraction is preferably 8-10 MPa, and the number of times of the supercritical CO2 extraction is preferably 2-3 times, and the time of each supercritical CO2 extraction is preferably 8-10 h.

[0045] In the present application, before the first extraction, the present application preferably soaks the Chrysanthemum cinerariaefolium residue with a polar solvent. The polar solvent used in the soaking is preferably an ethanol aqueous solution, and the volume percentage content of ethanol in the ethanol aqueous solution is preferably 80-85%. The ratio of the mass of the Chrysanthemum cinerariaefolium residue to the volume of the polar solvent used in the soaking is preferably (2-4) kg: 10 L, and more preferably 3 kg: 10 L. In the present application, the soaking is preferably carried out at room temperature, and the time of the soaking is preferably 24-48 h.

[0046] In the present application, after the soaking is completed, the present application preferably directly carries out the first extraction on the soaking system. The number of times of the extraction is preferably 3-4 times. The temperature of each extraction is preferably 50-55°C, and the time of each extraction is preferably 20-40 min, and more preferably 30 min. Each extraction is preferably carried out under heating reflux. The polar solvent used in the extraction is preferably an ethanol aqueous solution, and the volume percentage content of ethanol in the ethanol aqueous solution is preferably 80-85%. The solid-liquid ratio of each extraction is preferably (2-4) kg: 10 L, and more preferably 3 kg: 10 L. The solid-liquid ratio of each extraction is the ratio of the mass (kg) of the Chrysanthemum cinerariaefolium residue to the volume (L) of the polar solvent used in the extraction. The extraction is preferably carried out under normal pressure.

[0047] In the present application, after each extraction is completed, the present application preferably carries out solid-liquid separation on the system obtained by the extraction, and the solid-liquid separation is preferably filtration. The present application preferably combines the filtrates of the secondary extractions to obtain a total extract. The present application preferably concentrates the total extract to obtain a total crude extract.

[0048] After obtaining the total crude extract, the present application disperses the total crude extract in water, and extracts the obtained solution with ethyl acetate to obtain an ethyl acetate phase. In the present application, the water is preferably purified water. The number of times of the extraction is preferably 3 times. After the extraction, the organic phases are combined to obtain the ethyl acetate phase.

[0049] After obtaining the ethyl acetate phase, the present application concentrates the ethyl acetate phase to obtain the total ethyl acetate soluble product. In the present application, the concentration is preferably carried out under reduced pressure.

[0050] After obtaining the total ethyl acetate soluble product, the present application dissolves the total ethyl acetate soluble product in a methanol-dichloromethane mixture, then mixes the mixture with silica gel after removing the solvent to obtain a dry mixture, and then performs normal phase column chromatography separation. The normal phase column chromatography separation is carried out by gradient elution using a dichloromethane-methanol system with a volume ratio of dichloromethane to methanol being 1:0 to 0:1 in descending order, and the same fractions are combined to obtain nine fractions, which are named Fr.A to Fr.I fractions, respectively. In the present application, the volume ratio of methanol to dichloromethane in the methanol-dichloromethane mixture is preferably 15 to 20:1, and in the examples it can be 20:1. The silica gel used in the normal phase column chromatography separation is preferably 100 to 200 mesh silica gel. In the present application, the total ethyl acetate soluble product is dissolved in a methanol-dichloromethane mixture to obtain a mixed solution, and the present application preferably mixes the mixed solution with the silica gel used in the normal phase column chromatography separation and dries it before loading. The mass ratio of the total ethyl acetate soluble product to the silica gel is preferably 600 to 700:800, and more preferably 620 to 650:800, and in the examples it can be 641.1:800.

[0051] In the present application, the normal phase column chromatography separation is preferably carried out by gradient elution using a dichloromethane-methanol system with a volume ratio of 1:0, 40:1, 20:1, 10:1, and 0:1 in sequence. In the present application, each volume ratio is eluted for 5 column volumes, and then the eluents of each ratio are combined. The obtained eluents are subjected to thin layer chromatography (TLC), and the same fractions are combined to obtain nine fractions, which are named Fr.A fraction, Fr.B fraction, Fr.C fraction, Fr.D fraction, Fr.E fraction, Fr.F fraction, Fr.G fraction, Fr.H fraction, and Fr.I fraction, respectively. The normal phase column chromatography separation is preferably carried out at room temperature.

[0052] After obtaining the Fr.D fraction, the present application carries out first chromatographic separation on the Fr.D fraction, gradient elution is carried out on the dichloromethane-methanol system with the volume ratio of dichloromethane and methanol being 100:0-3:1 from large to small in volume ratio, and the same fractions are combined to obtain four sub-fractions, which are named as Fr.1-Fr.4 sub-fractions. In the present application, the first chromatographic separation is preferably: gradient elution is carried out on the dichloromethane-methanol system with the volume ratio of dichloromethane and methanol being 100:0, 40:1, 20:1, 10:1 and 3:1 in turn. In the present application, each volume ratio is eluted for 5 column volumes, and then the eluents of each ratio are combined. The obtained eluents are subjected to thin layer chromatography (TLC), and the same fractions are combined to obtain four sub-fractions, which are named as Fr.1 sub-fraction, Fr.2 sub-fraction, Fr.3 sub-fraction and Fr.4 sub-fraction, and the first chromatographic separation is preferably carried out at room temperature.

[0053] After obtaining the Fr.2 sub-fraction, the present application carries out second chromatographic separation on the Fr.2 sub-fraction, gradient elution is carried out on the dichloromethane-methanol system with the volume ratio of dichloromethane and methanol being 100:0-5:1 from large to small in volume ratio, and the same fractions are combined to obtain the natural insecticidal active compound with the structure shown in formula 1. In the present application, the second chromatographic separation is preferably: gradient elution is carried out on the dichloromethane-methanol system with the volume ratio of dichloromethane and methanol being 100:0, 40:1, 20:1, 10:1 and 5:1 in turn. In the present application, each volume ratio is eluted for 5 column volumes, and then the eluents of each ratio are combined. The obtained eluents are subjected to thin layer chromatography (TLC), and the same fractions are combined to obtain four fractions, which are named as Fr.2.1 sub-fraction, Fr.2.2 sub-fraction, Fr.2.3 sub-fraction and Fr.2.4 sub-fraction, and the second chromatographic separation is preferably carried out at room temperature.

[0054] The present application provides the application of the natural insecticidal active compound with the structure of formula 1 or the natural insecticidal active compound with the structure of formula 1 prepared by the preparation method in the insecticide.

[0055] In the present application, the insecticide is preferably an insecticide for killing aphids and / or mosquitoes. The aphid is preferably Myzus persicae. The mosquito is preferably Armigeres subalbatus.

[0056] In order to further illustrate the present application, the technical solutions provided by the present application are described in detail below in combination with examples, but they should not be understood as limiting the scope of protection of the present application.

[0057] The obtaining method of the chrysanthemum flower residue sample in the following examples is as follows:

[0058] First, dried pyrethrum flowers are placed in a supercritical CO2 extraction vessel for supercritical CO2 extraction, removing the essential oil from the flowers. The resulting residue is dried to form pyrethrum flower residue. The supercritical CO2 extraction pressure is 10 MPa, and each extraction lasts for 8 hours, with three extractions performed.

[0059] Example 1:

[0060] This embodiment provides a method for preparing a natural insecticidal compound (pyrethrindreg II) having a structure shown in Formula 1, which specifically comprises the following steps:

[0061] A sample of pyrethrum flower residue (15 kg) was first immersed in an ethanol solution (50 L) containing 80 vol% ethanol at room temperature for 48 hours. The sample was then reflux-extracted (at atmospheric pressure) three times with 50.0 L of an 80% ethanol solution containing 80 vol% ethanol at 55°C (30 minutes each extraction). The combined filtrates were concentrated under reduced pressure to obtain a crude total extract (831 g).

[0062] The total crude extract (831 g) was uniformly dissolved in purified water and partitioned three times with ethyl acetate (EtOAc); the combined EtOAc layers were concentrated under reduced pressure to obtain a total EtOAc-soluble product (641.1 g).

[0063] The total EtOAc-soluble product (641.1 g) was dissolved in a methanol (MeOH)-dichloromethane (DCM) mixture (the volume ratio of methanol to dichloromethane was 20:1), then mixed with 100-200 mesh silica gel (800.0 g), dried to remove the solvent, and then loaded onto a column for normal phase column chromatography separation; gradient elution was performed using DCM and methanol solutions with a volume ratio of DCM to methanol of 1:0, 40:1, 20:1, 10:1, and 0:1, and monitored by thin layer chromatography (TLC) to obtain nine fractions: Fr.A fraction, Fr.B fraction, Fr.C fraction, Fr.D fraction, FrE fraction, FrF fraction, FrG fraction, FrH fraction, and FrI fraction.

[0064] The Fr.D fraction was chromatographed on a silica gel column using a gradient elution with a DCM and methanol solution having a volume ratio of 100:0, 40:1, 20:1, 10:1, and 3:1. Monitoring by thin layer chromatography (TLC) yielded four subfractions: Fr.1 subfraction, Fr.2 subfraction, Fr.3 subfraction, and Fr.4 subfraction.

[0065] The Fr.2 sub-fraction was chromatographed on a silica gel column using a gradient elution of DCM and methanol in the ratio of 100:0, 40:1, 20:1, 10:1, 5:1, monitored by thin layer chromatography (TLC), to obtain four fractions: Fr.2.1 sub-fraction, Fr.2.2 sub-fraction, Fr.2.3 sub-fraction, Fr.2.4 sub-fraction. The Fr.2.1 fraction was dried to obtain the pyrethrin dreg II compound of the structure as shown in Formula 1.

[0066]

[0067] Example 2: Structure identification

[0068] The obtained compound pyrethrindreg II was identified by one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy (1D / 2D NMR) and high resolution electrospray ionization mass spectrometry (HR-ESI-MS) and its structure. Figure 1 The H-NMR spectrum of the compound pyrethrindreg II of the present application is as shown in Figure 1. 1 H-NMR spectrum; Figure 2 The C-NMR spectrum of the compound pyrethrindreg II of the present application is as shown in Figure 2. 13 C-NMR spectrum; Figure 3 The heteronuclear multiple bond correlation (HMBC) spectrum of the compound pyrethrindreg II of the present application is as shown in Figure 3. Figure 4 The heteronuclear single quantum correlation (HSQC) spectrum of the compound pyrethrindreg II of the present application is as shown in Figure 4. Figure 5 The HR-ESI-MS spectrum of the compound pyrethrindreg II of the present application is as shown in Figure 5.

[0069] Structure identification of pyrethrindreg II

[0070] The compound pyrethrindreg II prepared in Example 1 is a yellow oil, which shows fluorescence at 254 nm. After spraying with anisaldehyde / sulfuric acid reagent, it presents blue-black color. The HR-ESI-MS analysis determines the molecular formula as C + (C 22 H 31 O7406.1991 calculated) based on the observed protonated molecular ion peak m / z: 406.1992 [M+H] 22 H 30 O7, indicating an unsaturation degree of 8.

[0071] 1 H NMR spectrum of pyrethrin dreg II (CDC13, 400 MHz) shows signals at δ 1.24, 1.30, 1.94 and 2.06 indicative of four methyl groups, a signal at δ 3.73 corresponding to a methoxy group, and olefinic protons resonating at δ 5.39 and 5.53.

[0072] 13 C NMR and DEPT spectra revealed the following carbon signals: four methyl carbons at δ 13.0, 14.1, 20.5 and 22.5; a methoxy carbon at δ 52.0; three methylene carbons at δ 14.2, 42.2 and 66.2; seven methine carbons at δ 33.1, 35.8, 67.9, 73.3, 128.3, 128.5 and 139.0; seven quaternary carbons at δ 30.8, 130.5, 141.4, 166.3, 168.2, 171.3 and 205.2.

[0073] Key structural fragments of pyrethrin dreg II were identified by 2D NMR spectroscopy. HSQC data supported the presence of a methoxy group at δ 52.0 and a methyl group at δ 22.5. The presence of a cyclopropane ring was confirmed by HMBC correlations of H-7 and H-8 to C-15 and C-16. 1 H- 1 HCOSY spectrum revealed spin systems corresponding to fragments C-5'-C-4'-C-3'-C-2'-C-1' (through correlations H2-5' / H-4' / H-3' / H-2' / H2-1'), C-4-C-5 (H-4 / H2-5), and C-7-C-8-C-10 (H-7 / H-8 / H-10). Long-range HMBC correlations were crucial in assembling the structure: H-4 correlations to C-1, C-2, C-3 and C-6; from H-7 to C-10, C-15 and C-16; from H-8 to C-16 and C-11; from H-10 to C-9 and C-14 established the planar portion C-7-C-8-C-9-C-15-C-16-C-11-C-14. Crucially, HMBC correlations of H-7 and H-8 to C-15 and C-16 established the presence of a cyclopropane ring in this system. HMBC correlations of H to C-12 2-1' from C-1, C-3 and C-3', and from H-3' to C-5' confirmed the connectivity of the C-5'-C-4'-C-3'-C-2'-C-1' fragment.

[0074] 1H NMR (400 MHz, CDCl3): δ 6.45 (1H, m, H-10), 5.66 (1H, m, H-4), 5.53 (1H, t, J = 9.5 Hz, H-2′), 5.39 (1H, td, J = 10.1, 6.8 Hz, H-3′), 4.72), 2.10-2.07 (2H, m, H2-1′), 2.06 (3H, s, H3-17), 1.94 (3H, d, J = 1.3 Hz, H3-14), 1.73 (1H, dd, J = 5.3, 1.4 Hz, H-7), 1.30 (3H, s, H3-16), 1.24 (3H, d, J = 1.3 Hz, H3-15); 13 C NMR (100 MHz, CDCl3): δ 205.2 (C-1), 171.3 (C-6), 168.2 (C-12), 166.3 (C-3), 141.4 (C-2), 139.0 (C-10), 130.5 (C-11), 128.5 (C-2'), 128.3 (C-3'), 73.3 (C-4), 67.9 (C-4'), 66.2 (C-5'), 52.0 (C-13), 42.2 (C-5), 35.8 (C-7), 33.1 (C-8), 30.8 (C-9), 22.5 (C-15), 20.5 (C-16), 14.2 (C-1'), 14.1 (C-17), 13.0 (C-14).

[0075] 1 H NMR (400MHz, CDCl3) δ6.45(1H,m,H-10),5.66(1H,m,H-4),5.53(1H,t,J=9.5Hz,H-2′),5.39(1H,td,J=10.1, 6.8Hz,H-3′),4.72(1H,m,H-4′),3.73(3H,s,H-13),3.65(1H,m,H-5′α),3.55(1H,m,H-5′β),2.89(1H,dd,J= 18.8,6.2Hz,H-5α),2.19(1H,m,H-5β),2.23(1H,m,H-8),2.10-2.07(2H,m,H2-1′),2.06(3H,s,H3-17),1.94 (3H,d,J=1.3Hz,H3-14),1.73(1H,dd,J=5.3,1.4Hz,H-7),1.30(3H,s,H3-16),1.24(3H,d,J=1.3Hz,H3-15); 13C NMR (100 MHz, CDC13): δ 205.2 (C-l), 171.3 (C-6), 168.2 (C-12), 166.3 (C-3), 141.4 (C-2), 139.0 (C-10), 130.5 (C-l 1), 128.5 (C-2'), 128.3 (C-3'), 73.3 (C-4), 67.9 (C-4'), 66.2 (C-5'), 52.0 (C-13), 42.2 (C-5), 35.8 (C-7), 33.1 (C-8), 30.8 (C-9), 22.5 (C-15), 20.5 (C-16), 14.2 (C-l'), 14.1 (C-17), 13.0 (C-14).

[0076] Example 3:

[0077] This example uses the industry standard pesticide indoor biological test guidelines, part 9, spray method:

[0078] (1) Select indoor continuous feeding, physiological state of the same tobacco aphid or Anopheles;

[0079] (2) The compound pyrethrin dreg II and positive control drug imidacloprid are prepared into 1 mg / mL stock solution using organic solvent acetone, and then 0.1% Tween-80 aqueous solution is used to prepare five series of mass gradients of 100, 60, 30, 10, 3.3 mg / L, which are divided into 5 5 mL small spray bottles; The compound pyrethrin dreg II and the positive control drug cypermethrin are prepared into 1 mg / mL stock solution using organic solvent acetone, and then 0.1% Tween-80 aqueous solution is used to prepare five series of mass gradients of 5, 1, 0.5, 0.1, 0.05 mg / L, which are divided into 5 5 mL small spray bottles

[0080] (3) The culture dish is pierced with an iron needle to form many small holes for air circulation, and a round cabbage leaf of the same size as the culture dish is placed in the culture dish. 20 tobacco aphids or Anopheles with the same physiological state are selected and placed in the culture dish using a brush, and then the front and back are quantitatively sprayed with 1 mL of liquid. Each treatment is repeated 4 times, and a treatment without drug (containing all solvents and emulsifiers) is used as a blank control.

[0081] (4) The treated tobacco aphids and Anopheles are raised and observed under the conditions of temperature (25±1) °C, relative humidity 60%-80%, and light cycle L:D (16:8) h.

[0082] (5) The mortality of pests after treatment for 24 h is recorded, and the total number of insects and the number of dead insects are recorded respectively.

[0083] (6) Data statistics and analysis: according to the survey data, the corrected mortality of each treatment is calculated.

[0084] P = K / N x 100% formula (1);

[0085] In formula (1), P represents mortality, unit: percent (%); K represents the number of dead insects, unit: head; N represents the total number of insects in the treatment, unit: head.

[0086] P1 = (Pt-P0) / (1-p0)"x 100% formula (2);

[0087] In formula (2), P1 represents the corrected mortality, unit: percent (%); P represents the treatment mortality, unit: percent (%); P0 represents the blank control mortality, unit: percent (%). t

[0088] If the control mortality is less than 5%, no correction is needed; if the control mortality is between 5% and 20%, the correction should be made according to formula 2; if the control mortality is greater than 20%, the test needs to be redone.

[0089] (7) The data is processed by using the method of odds value analysis, and GraphPad Prism 9 software is used for analysis to calculate the LC 50 value.

[0090] The insecticidal activity LC 50 values of compound pyrethrindreg II on Myzus persicae and Armigeres subalbatus are 9.4914 mg / L and 0.5770 mg / L respectively, and the insecticidal activity LC 50 values of positive control imidacloprid on Myzus persicae and cypermethrin on Armigeres subalbatus are 1.2719 mg / L and 0.0764 mg / L respectively. Compound pyrethrindreg II shows significant insecticidal activity on Myzus persicae and Armigeres subalbatus, although it does not exceed the positive control, but it is of great significance for the development of new biological insecticides. The method for extracting a large amount of compound pyrethrindreg II with good insecticidal activity based on chrysanthemum cinerariaefolium is not only in line with the needs of modern environmental protection and low-carbon economy, and realizes the reuse of waste, but also lays a solid foundation for further research and industrialization development and application of the insecticide industrialization production in the later stage, and has broad market application prospect.

[0091] Although the above embodiment makes a detailed description of the present application, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained according to the present embodiment without creativity, which all belong to the protection scope of the present application.​

Claims

1. A natural insecticidal active compound, characterized in that: It has the structure shown in formula 1:

2. The method for preparing the natural insecticidal active compound according to claim 1, characterized in that: The following steps are involved: (1) extracting pyrethrum flower residue with a polar solvent to obtain an extract, and concentrating the extract to obtain a total crude extract; (2) dispersing the total crude extract in water, and extracting the resulting solution with ethyl acetate to obtain an ethyl acetate phase; (3) concentrating the ethyl acetate phase to obtain a total ethyl acetate-soluble product; (4) dissolving the total ethyl acetate-soluble product in a methanol-dichloromethane mixture, mixing the sample with silica gel, and removing the solvent. The obtained dry mixture is loaded onto a column for separation by normal phase column chromatography. The normal phase column chromatography separation is performed in a dichloromethane-methanol system with a volume ratio of dichloromethane to methanol of 1:0 to 0:1 according to a decreasing volume ratio. Identical fractions are combined to obtain nine fractions, which are named as Fr.A to Fr.I fractions respectively. (5) subjecting the Fr.D fraction to a first chromatographic separation, wherein the first chromatographic separation is performed by gradient elution using a dichloromethane-methanol system with a volume ratio of dichloromethane to methanol of 100:0 to 3:1, and combining the same fractions to obtain four sub-fractions, respectively named Fr.1 to Fr.4; (6) The Fr.2 subfraction is subjected to a second chromatographic separation, wherein the second chromatographic separation is performed in a gradient elution system of dichloromethane and methanol with a volume ratio of dichloromethane to methanol of 100:0 to 5:1 according to a decreasing volume ratio, and the same fractions are combined to obtain a natural insecticidal active compound with a structure represented by Formula 1.

3. The preparation method according to claim 2, characterized in that In step (1), the extraction is performed 3 to 4 times, the temperature of each extraction is 50 to 55° C., and the time of each extraction is 20 to 40 minutes.

4. The preparation method according to claim 2 or 3, characterized in that In step (1), the polar solvent is an ethanol aqueous solution, the volume percentage of ethanol in the ethanol aqueous solution is 80-85%; the solid-liquid ratio of each extraction is (2-4) kg:10L.

5. The preparation method according to claim 2, characterized in that In step (4), the volume ratio of methanol to dichloromethane in the methanol-dichloromethane mixture is 15 to 20:

1.

6. The preparation method according to claim 2, characterized in that In step (4), the silica gel used for separation by normal phase column chromatography is 100-200 mesh silica gel; The normal phase column chromatography separation method comprises the following steps: gradient elution is performed using a dichloromethane-methanol system with a volume ratio of 1:0, 40:1, 20:1, 10:1, and 0:1 in sequence.

7. The preparation method according to claim 2, characterized in that In the step (5), the first chromatographic separation is: gradient elution is performed using a dichloromethane-methanol system with volume ratios of 100:0, 40:1, 20:1, 10:1, and 3:1 in sequence.

8. The preparation method according to claim 2, characterized in that In the step (6), the second chromatographic separation is: gradient elution is performed using a dichloromethane-methanol system with volume ratios of 100:0, 40:1, 20:1, 10:1, and 5:1 in sequence.

9. Use of the natural insecticidal active compound having the structure of Formula 1 according to claim 1 or the natural insecticidal active compound having the structure of Formula 1 prepared by the preparation method according to any one of claims 2 to 8 in insecticides.

10. The use according to claim 9, characterized in that The insecticide is an insecticide for killing aphids and / or mosquitoes.

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