Novel indole compound and application thereof

Abstract

The invention discloses a novel indole compound, the chemical structural formula of which is as follows: # imgabs0. The novel natural compound is obtained by utilizing fungus co-culture fermentation, shows good inhibitory activity on growth of radicles of gramineous weeds barnyard grass, and has a remarkable damage effect on root tip cells of the gramineous weeds barnyard grass.

Description

Technical Field

[0001] The invention relates to the field of natural products, and in particular to a new indole compound. Background Art

[0002] Endophytic fungi are fungi that live in plant tissues for the entire or part of their life cycle without causing any harmful effects on the host. Microorganisms are one of the main sources of natural secondary metabolites. Due to the gene silencing phenomenon of biosynthetic gene clusters (BGCs) in microorganisms, especially fungi, they are not expressed or expressed at a low level under laboratory culture conditions. The secondary metabolites produced by microorganisms are low in content and have a single skeleton type.

[0003] Echinochloa crus-galli (L.) P.Beauv. is an annual grass weed with strong adaptability and tolerance to adverse environments. It is one of the most malignant weeds in rice fields across the country. The main measure for the control of barnyard grass is chemical control, but the long-term use of chemical herbicides will cause environmental pollution, and the resulting weed resistance problem is becoming increasingly prominent. Therefore, it is urgent to find a new herbicide to solve the problems faced by the existing barnyard grass damage. Summary of the invention

[0004] The purpose of the present invention is to solve the defects in the prior art and provide a natural product with herbicidal effect.

[0005] In order to achieve the above object, the technical solution provided by the present invention is as follows:

[0006] A new indole compound, the chemical structure of which is as follows:

[0007]

[0008] The present invention obtains a new indole compound (hereinafter named Colletotriauxin G), which is a hidden natural product obtained by activating a microbial silent gene cluster by co-cultivation with fungi. The new indole compound of the present invention has a natural source, does not cause environmental pollution and poses a potential risk to humans, and has a good barnyard grass growth inhibition effect, expanding the application of natural products in weed control.

[0009] The fungi co-cultured above use the following fungi: an endophytic fungus of the genus Alternaria A. destruens CIY4 isolated from chicory leaves and a wolfberry anthracnose pathogen C. acutatum.

[0010] The present invention can stimulate the silent genes of microorganisms to produce secondary metabolites through fungal co-culture fermentation, thereby obtaining hidden natural products, and extracting and separating new indole compounds therefrom, which can be used for the preparation of natural source herbicides.

[0011] The present invention also provides the application of the novel indole compound in weed control, especially in the preparation of natural herbicides.

[0012] In some embodiments, as a preference, when the novel indole compounds are used to prepare natural herbicides, the concentration of the novel indole compounds is preferably 50 μg / mL to 100 μg / mL.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] The present invention uses a fungal co-cultivation method to activate silent gene clusters to obtain hidden natural products, and screens out compounds with excellent weed control effects, thereby expanding the sources and applications of natural herbicides.

[0015] The compound obtained by the invention is a new indole compound, which not only expands the natural source of indole compounds, but also provides a new leading compound for the research and development of herbicide biopesticides through its growth inhibition effect on young roots of barnyard grass. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is the chemical structural formula of the new indole compound Colletotriauxin G of the present invention;

[0017] Figure 2 The key to the new indole compound Colletotriauxin G of the present invention 1 H- 1 H COSY, HMBC and NOESY correlation diagrams;

[0018] Figure 3 The mass spectrum of the new indole compound Colletotriauxin G of the present invention;

[0019] Figure 4 This is the IR spectrum of the new indole compound Colletotriauxin G of the present invention;

[0020] Figure 5 This is the UV spectrum of the new indole compound Colletotriauxin G of the present invention;

[0021] Figure 6 This is the hydrogen spectrum of the new indole compound Colletotriauxin G of the present invention;

[0022] Figure 7 This is the carbon spectrum of the new indole compound Colletotriauxin G of the present invention;

[0023] Figure 8 The novel indole compound Colletotriauxin G of the present invention 1 H- 1 H COSY diagram;

[0024] Fig. 9 It is the HMBC diagram of the new indole compound Colletotriauxin G of the present invention;

[0025] Fig.10 This is the HSQC chart of the new indole compound Colletotriauxin G of the present invention;

[0026] Fig.11 It is the NOESY diagram of the new indole compound Colletotriauxin G of the present invention;

[0027] Fig.12 This is a comparison chart of the activity of Colletotriauxin G, a new indole compound of the present invention, in inhibiting the growth of young roots of barnyard grass at different concentrations;

[0028] Fig.13 This is a comparison chart of the effects of different concentrations of the new indole compound Colletotriauxin G on the growth of young roots of barnyard grass;

[0029] Fig.14 This is a comparison chart of the damage to young root cells of Echinochloa crusgalli treated with the new indole compound Colletotriauxin G of the present invention at different concentrations. DETAILED DESCRIPTION

[0030] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Example 1

[0032] Preparation Example of the New Indole Compound Colletotriauxin G of the Present Invention

[0033] The present invention activates and cultures the endophytic fungus A. destruens CIY4 of the genus Alternaria and the anthracnose fungus C. acutatum isolated from chicory leaves (see Liu Yang, Meng Xiuhua, Lv Han, et al. Isolation of endophytic fungi from chicory leaves and analysis of their anti-plant pathogenic activity [J / OL]. Journal of Plant Resources and Environment, 1-4 [2024-12-10]. http: / / kns.cnki.net / kcms / detail / 32.1339.S.20240912.1009.002.html.). The activation culture conditions are as follows: A. destruens CIY4 and C. acutatum are inoculated into potato dextrose agar medium (PDA) at 27±1°C for 5 days. Then, the bacterial blocks are inoculated into potato dextrose broth medium (PDB) respectively, and cultured at 27-28°C and 160r / min for 7 days to obtain seed liquid. The seed liquid of A. destruens CIY4 and C. acutatum was inoculated into the sterilized and cooled rice culture medium at a ratio of 1:1, and fermented at room temperature of about 25°C for 30 days. 3 OH) was extracted three times to completely immerse the rice and fermented products in the solvent, each time for 1 day, and the three extracts were combined and concentrated under reduced pressure using a rotary evaporator until there was no methanol smell to obtain a total extract of 1.6 kg. An appropriate amount of ultrapure water was added for suspension, and the same volume of ethyl acetate (EtOAc) was used for extraction. The total extraction was performed three times to obtain 41.6 g of ethyl acetate extract. The ethyl acetate extract was initially separated by silica gel column chromatography, mixed with 100-200 mesh silica gel, loaded on a 100-200 mesh silica gel column, and a petroleum ether (PE) / ethyl acetate (EtOAc) solvent system (100:0-100:100) and dichloromethane (CH 2 Cl 2 ) / Methanol(CH 3 OH) solvent system (100:4~0:100) was used for gradient elution, and the same components were combined by HPLC detection to obtain components Fr.1-Fr.5. Component Fr.5 was gradient eluted by silica gel column (CH 2 Cl 2 :CH 3 OH=100:4~100:16), and obtained subcomponents Fr 5.1-Fr 5.5. The Fr 5.5 part was subjected to semi-preparative high performance liquid chromatography (40% CH 3 CN) was purified, and the obtained monomer compounds were screened for activity, and the compound Colletotriauxin G with barnyard grass growth inhibitory activity was obtained, and the following spectral techniques (such as MS, NMR, UV, IR, etc.) were used for structural identification:

[0034] Compound Colletotriauxin G, light white powder. The spectral data are as follows (combined Figure 2 to Figure 11 ): [α] 25 D = +31.579°(c 0.038, CH 3 OH); UV(CH 3 OH)λ max 218.6, 279.3nm; IR (KBr) ν max 3356, 2924, 2853, 1717, 1457, 1178, 1078, 1034cm -1 ; Based on HR-ESI-MS data, m / z 336.1463[M+H] + (Calcd.forC 17 H 22 NO 6 336.1442), the molecular formula of the compound is inferred to be C 17 H 21 NO 6 , the unsaturation is 8. 1 The δ H 7.18 (1H, s, H-2), 7.62 (1H, d, J = 7.9, H-4), 7.02 (1H, t, J = 7.5, H-5), 7.10 (1H, t, J = 6.9, H-6), 7.34 (1H, d, J = 8.1, H-7), it is inferred that there is a typical 3-substituted indole structure, a methyl δ H 1.61 (3H, d, J = 7.2, H-3'), a methine group connected to a methyl group H The results are as follows: 1H, m, H-2′, 4.10 (1H, m, H-2′), four oxymethine signals at 4.98 (1H, ddd, J=8.3, 4.8, 3.5, H-2″), 4.10 (1H, m, H-3″), 3.41 (1H, dd, J=8.4, 1.2, H-4″), 3.68 (1H, ddd, J=8.5, 6.0, 3.4, H-5″), and two oxymethylene signals at 3.76 (1H, d, J=4.2, H-1″), 3.83 (1H, dd, J=12.0, 3.6, H-1″), 3.53 (1H, dd, J=11.3, 6.1, H-6″) and 3.73 (1H, d, J=3.4, H-6″).

[0035] Table 1 NMR spectrum data of compound Colletotriauxin G

[0036]

[0037] As shown in the table above, 13 C NMR showed the presence of 17 carbon signals, including an ester carbonyl carbon δ C 176.8 (C-1'), one methyl carbon delta C 18.2 (C-3'), two oxymethylene carbons δ C 62.0(C-1”),δ C 65.1(C-6”), 1 methylene carbon δ C 38.5 (C-2'), 4 oxygen methylene carbon delta C 75.5(C-2”),δ C 69.2(C-3”),δ C 71.2(C-4”),δ C 72.6 (C-5"), 8 indole carbons C 123.2(C-2),δ C 115.3(C-3),δ C 127.6(C-3a),δ C 119.7(C-4),δ C 119.8(C-5),δ C 122.5(C-6), 112.4(C-7), δ C 138.0 (C-7a). HMBC correlations of H-5 / C-3a, H-6 / C-4, C-7a, H-7 / C-3a, H-2 / C-3a, and C-7a showed the presence of indole, and the HMBC spectrum showed δ C The aromatic carbon C-3a at 127.6 and δ C The correlation of the methine carbon C-2' at 38.5 indicated the C-3 substitution of the indole moiety, and the HMBC correlation of H-3' / C-3, C-1' indicated the presence of a methylated indole 3-acetoxy moiety. Further, based on the COSY correlation, the presence of a -CH2-CH-CH-CH-CH2-linked hexose fragment was inferred, and the HMBC correlations of H-3" / C-1", C-5", H-4" / C-2", H-1" / C-5", and H-4" / C-6" further confirmed the fragment.

[0038] The HMBC correlation of H-2" / C-1' proved that the 2" position of the hexose fragment was connected to the indole terminal through an ethyl ester bond. The above NMR data analysis showed that the compound was a 3-(2'-methyl)-ethyl ester-1,2-deoxyglucose substituted indole. In addition, according to the NOESY spectrum ( Figure 2 and Fig.11 ) is related to 2" / 5" and 3" / 5", and it is inferred that 2", 3", and 5" are on the same side in the six-membered ring. Therefore, its structural formula and relative configuration are as follows Figure 1 As shown, it is a new compound named Colletotriauxin G.

[0039] Example 2

[0040] Test of the growth inhibition activity of the compound Colletotriauxin G on the young roots of the grass weed Echinochloa crus-galli

[0041] The present invention adopts the plate method to determine the inhibitory activity of the compound Colletotriauxin G on the young root growth of barnyard grass, and glyphosate is used as a positive control drug. First, 3 mg of the compound is dissolved in a small amount of DMSO, so that the final content of DMSO in the test solution is below 0.1%, 0.1% Tween 20 is added to 3 mL, and a 1 mg / mL mother solution is prepared, and then the test solution of the corresponding concentration is prepared according to Table 2. The barnyard grass seeds are pre-treated by soaking in sterile deionized water for 1 day in advance, disinfected with 75% alcohol for 5 minutes, washed with sterile deionized water 3 times, each time for 30 seconds, two filter papers are laid flat on each culture dish, and 5 mL of the above test solution is added, and an aqueous solution containing 0.1% (v / v) dimethyl sulfoxide and 0.1% (v / v) Tween 20 is used as a solvent control ( Fig.13 , 14 Solvent group) and sterile deionized water as blank control ( Fig.13 CK group as shown), 10 seeds were placed in each dish, sealed with stretch film, and cultured at 23℃, 70% humidity, 14000 light intensity, light / dark (16h / 8h) for 4 days, and each concentration was repeated 3 times. After 4 days, photos were taken, and the length of the young roots of barnyard grass was calculated using Image J, and the data were analyzed using GraphPad Prism 8.0.2. Results (as shown in Fig.12 , 13) showed that the compound Colletotriauxin G showed a significant inhibitory effect on the growth of young roots of barnyard grass starting from a concentration of 50 μg / mL, and there was no significant difference in its inhibitory effect on young roots of barnyard grass compared with glyphosate.

[0042] Table 2 Preparation method of gradient concentration test solution

[0043]

[0044] Example 3

[0045] Effects of Colletotriauxin G on Root Tip Cells of Echinochloa crus-galli Seedlings

[0046] The present invention uses propidium iodide (PI) staining to detect the effect of the compound on the root tip cells of barnyard grass seedlings. The barnyard grass seedlings treated with the compound in Example 2 for 4 days were stained with 10 μg / mL PI stain for 30 minutes, washed with 0.01M PBS buffer, and placed under a laser scanning confocal microscope to observe the treated root tips at a wavelength of 561nm. The experiment was repeated 3 times and images were recorded. Results (such as Fig.14 The results showed that compared with the blank control group (CK group), the root tip cells of barnyard grass seedlings treated with the compound Colletotriauxin G were damaged, and with the increase of concentration, the damage to the root tip cells of barnyard grass seedlings was obvious at 50 μg / mL, and the effect was significant. There was no significant difference between the damaging effect and the glyphosate treatment group, indicating that the compound had a significant damaging effect on the root tip cells of barnyard grass.

Claims

1. A new indole compound, the chemical structure of which is as follows:

2. Use of the new indole compound according to claim 1 in weed control.

3. Use of the new indole compound according to claim 1 in the preparation of a natural herbicide, characterized in that: The indole compound is used for preparing a natural source herbicide, wherein the concentration of the indole compound is 50 μg / mL to 100 μg / mL.

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