Application of camptothecin derivative as herbicide

Abstract

The invention discloses an application of a camptothecin derivative as a herbicide. The research shows that the camptothecin derivatives hydroxycamptothecin, 7-ethyl-10-hydroxycamptothecin and 9-aminocamptothecin have obvious inhibition effects on root growth and plant growth of various common typical weeds, have relatively broad-spectrum herbicidal activity, comprise dicotyledonous weeds such as amaranthus retroflexus, bidens pilosa, mikania micrantha, ageratum conyzoides, feather cockscomb and mimosa pudica, and have broad-spectrum herbicidal activity, such as amaranthus retroflexus, bidens pilosa, mikania micrantha, ageratum conyzoides, feather cockscomb and mimosa pudica. Moreover, the weeding effect is remarkable, and the weeding composition is superior to the weeding agent glyphosate which is most commonly used in agriculture; and the compound is derived from natural plants, is high in ecological safety and environment-friendly, and has very good application value and prospect in the aspect of developing herbicides. Furthermore, the camptothecin derivatives can be applied to field production through dosage form processing, and have the advantages of environmental protection and efficient utilization of resources. The application of the invention can promote diversified development of plant resources and assist sustainable agricultural development.

Description

Technical Field

[0001] The present invention belongs to the technical field of pesticides, and specifically relates to herbicides, and more specifically to the use of camptothecin derivatives as herbicides. Background Art

[0002] Herbicides, as a specific class of chemical substances, primarily eliminate or inhibit the growth of weeds through selective or non-selective mechanisms of action. In agricultural production, herbicides with high efficacy, low toxicity, and broad spectrum activity are becoming increasingly important. Their application continues to expand, playing an irreplaceable role in increasing crop yields and farmland management efficiency.

[0003] Alkaloids are a class of nitrogen-containing organic compounds with alkaline characteristics. They are naturally distributed in a variety of organisms, especially in the plant kingdom, and are also found in some animals. Studies have confirmed that this type of natural product not only exhibits significant biological activity, but its multifunctional properties also show important application value in the fields of medicine (such as drug development) and agriculture (such as plant protection), making it a key research focus in modern biotechnology. The systematic research and development of alkaloids has both profound academic value and industrial potential. Its research and development system includes two innovative dimensions: it includes functional expansion research of existing structural alkaloids (focusing on the development of cross-domain application value), and covers the systematic exploration of new alkaloid resources (including structural analysis and activity verification). By deepening the research on pharmacological mechanisms and the development of industrial application technologies, it is possible to effectively promote the transformation of these natural active molecules into functional products that meet the needs of social development.

[0004] Camptothecin is an alkaloid extracted from Camptotheca acuminata Decne. Its current agricultural applications primarily focus on insecticides and antibacterials. Studies have shown that camptothecin has activity against a broad spectrum of agricultural pests, including those of the orders Homoptera, Thysanoptera, Lepidoptera, and Coleoptera, with high activity and good applicability. Furthermore, camptothecin can inhibit diseases such as cucumber downy mildew, cucumber powdery mildew, rice sheath blight, tobacco brown spot pathogen, and corn scab. However, research on camptothecin's use in agricultural weed control is limited. Dai Wei et al. demonstrated that camptothecin has some inhibitory activity against mustard, amaranth, and crabgrass; while Fan Xiaoyue et al. demonstrated some allelopathic inhibitory effects against white clover, philadelphus, pansy, ophiopogon japonicus, and iris. However, the range of weeds it can target is limited, and its weed control effectiveness needs to be improved. Summary of the Invention

[0005] The present invention aims to explore camptothecin derivatives with excellent and broad-spectrum herbicidal activity for their application as agricultural herbicides. Research has shown that hydroxycamptothecin, 7-ethyl-10-hydroxycamptothecin, and 9-aminocamptothecin exhibit broad-spectrum herbicidal efficacy against typical dicotyledonous weeds, including Amaranthus retroflexus, Bidens pilosa, Mikania micrantha, Artemisia selengensis, Acer truncatum, and Mimosa pudica, as well as monocotyledonous weeds such as Echinochloa crusgalli, Digitaria sanguinalis, Juncus citriodora, and Eleocharis chinensis. These derivatives can be formulated into herbicides for use as herbicides.

[0006] The purpose of the present invention is to provide the use of camptothecin derivatives in weeding and preparing herbicides.

[0007] Another object of the present invention is to provide the use of plant extracts rich in camptothecin derivatives in weeding and preparing herbicides.

[0008] Another object of the present invention is to provide a herbicide containing a camptothecin derivative.

[0009] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0010] After extensive research, the present invention has discovered new uses for three camptothecin derivatives, namely, hydroxycamptothecin, 7-ethyl-10-hydroxycamptothecin, and 9-aminocamptothecin. These three camptothecin derivatives have an inhibitory effect on the root growth and plant growth of typical weeds such as dicotyledonous weeds Amaranthus retroflexus, Bidens pilosa, Mikania micrantha, Artemisia selengensis, Acer truncatum, and Mimosa pudica, as well as monocotyledonous weeds such as Echinochloa crusgalli, Digitaria sanguinalis, Juncus wicker, and Goosegrass. The invention has a relatively broad-spectrum herbicidal activity and a significant herbicidal effect.

[0011] Therefore, the present invention claims protection for the following solutions:

[0012] Application of camptothecin derivatives in herbicides.

[0013] Use of camptothecin derivatives as herbicides.

[0014] Application of camptothecin derivatives in the preparation of herbicides.

[0015] Application of plant extracts rich in camptothecin derivatives in herbicidal applications.

[0016] Use of plant extracts rich in camptothecin derivatives as herbicides.

[0017] Application of plant extracts rich in camptothecin derivatives in the preparation of herbicides.

[0018] The camptothecin derivative is any one or more of hydroxycamptothecin, 7-ethyl-10-hydroxycamptothecin, and 9-aminocamptothecin.

[0019] These three camptothecin derivatives can exert excellent and relatively broad-spectrum herbicidal activity when used alone, and can also be used in combination to enhance the herbicidal effect.

[0020] Specifically, the plant extract rich in camptothecin derivatives refers to a plant extract whose main active substance is a camptothecin derivative.

[0021] Optionally, the plant extract is an extract of Camptotheca acuminata, more preferably an extract of Camptotheca acuminata seeds, roots or bark.

[0022] Based on the above application, the present invention further provides a herbicide, wherein the herbicidal active ingredient comprises a camptothecin derivative, or comprises an extract of Camptothecin containing a camptothecin derivative.

[0023] Furthermore, in addition to the active ingredients, the herbicide may also be added with pesticide adjuvants to prepare various dosage forms.

[0024] This invention optimizes the formulation process of the camptothecin derivatives hydroxycamptothecin, 7-ethyl-10-hydroxycamptothecin, and 9-aminocamptothecin to form an environmentally friendly technology carrier, achieving both ecological compatibility and resource recycling efficiency in field applications. The application of this invention can promote the multi-level development of plant active ingredients, help expand the multi-dimensional utilization of plant resources, promote green agriculture, establish a low-carbon circular agricultural model, provide technical support for the construction of an ecological agricultural system, and promote the implementation of an environmentally friendly agricultural development model.

[0025] The present invention also provides a method for controlling weeds, which comprises using the camptothecin derivatives or herbicides containing the camptothecin derivatives to control weeds.

[0026] In addition, the weed types that can be targeted by the present invention include dicotyledonous weeds and / or monocotyledonous weeds.

[0027] More specifically and preferably, the dicotyledonous weeds include one or more of Amaranthus retroflexus, Bidens pilosa, Mikania micrantha, Artemisia selengensis, Acer truncatum, and Mimosa pudica.

[0028] The monocotyledonous weeds include one or more of barnyard grass, crabgrass, rush, and goosegrass.

[0029] The present invention has the following beneficial effects:

[0030] The present invention provides new uses of camptothecin derivatives, including hydroxycamptothecin, 7-ethyl-10-hydroxycamptothecin, and 9-aminocamptothecin, which have an inhibitory effect on the root growth and plant growth of typical weeds such as dicotyledonous weeds Amaranthus retroflexus, Bidens pilosa, Mikania micrantha, Artemisia selengensis, Acer truncatum, and Mimosa pudica, as well as monocotyledonous weeds such as Echinochloa crusgalli, Digitaria sanguinalis, Juncus citriodora, and Goosegrass. The invention has broad-spectrum herbicidal activity and significant herbicidal effect, and is superior to glyphosate, the most commonly used herbicide in agriculture.

[0031] Furthermore, these camptothecin derivatives are derived from readily available natural ingredients and exhibit efficient degradation in the natural environment. Their decomposition process conforms to ecological cycles, enabling complete biodegradation without forming harmful residues. Rapid mineralization prevents environmental accumulation while maintaining a balanced soil microbial community. This makes them remarkably environmentally friendly, fundamentally avoiding secondary pollution caused by chemical pesticide residues and effectively preventing persistent impacts on ecosystems.

[0032] Furthermore, these camptothecin derivatives possess dual insecticidal and antibacterial properties, effectively inhibiting weed growth in fields while also providing synergistic control of pests and diseases. This multi-target mechanism of action gives these compounds the advantage of "one dose, multiple effects" in agricultural plant protection, significantly enhancing the overall benefits of plant protection.

[0033] Fourth, the present invention's research on the herbicidal effects of camptothecin derivatives and their use as agricultural chemicals can promote the comprehensive development and utilization of plant resources containing such substances, while simultaneously exploring multi-dimensional value development space for medicinal and agricultural uses, ultimately forming an eco-friendly plant resource comprehensive utilization system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The graph shows the inhibitory effect of hydroxycamptothecin on several typical dicotyledonous weeds (7 days after cultivation).

[0035] Figure 2 The graph shows the inhibitory effect of hydroxycamptothecin on several typical monocotyledonous weeds (7 days after cultivation).

[0036] Figure 3 The inhibitory effect of 7-ethyl-10-hydroxycamptothecin on several typical dicotyledonous weeds (7 days after incubation).

[0037] Figure 4 The inhibitory effect of 7-ethyl-10-hydroxycamptothecin on several typical monocotyledonous weeds (7 days after incubation).

[0038] Figure 5 The inhibitory effect of 9-aminocamptothecin on several typical dicotyledonous weeds (7 days after incubation).

[0039] Figure 6 The inhibitory effect of 9-aminocamptothecin on several typical monocotyledonous weeds (7 days after incubation).

[0040] In the figure, CK is the blank control. DETAILED DESCRIPTION

[0041] The present invention is further described below with reference to specific embodiments and accompanying drawings, but the embodiments do not limit the present invention in any form.

[0042] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0043] Unless otherwise specified, all reagents and materials used in the following examples were commercially available.

[0044] Hydroxycamptothecin, CAS No. 19685-09-7, molecular formula C 20 H 16 N2O5.

[0045] 7-Ethyl-10-hydroxycamptothecin, CAS No. 86639-52-3, molecular formula C 22 H 20 N2O5.

[0046] 9-Aminocamptothecin, CAS No. 91421-43-1, molecular formula C 20 H 17 N3O4.

[0047] Homocamptothecin, CAS number 50906-88-2, molecular formula C 21 H 18 N2O4.

[0048] Example 1 Test on root growth inhibition of common weeds by hydroxycamptothecin

[0049] Hydroxycamptothecin and berberine were prepared into stock solutions of varying concentrations and then diluted with Hoagland's broth to concentrations of 400 mg / L, 200 mg / L, 100 mg / L, and 50 mg / L. Glyphosate was diluted to 2000 mg / L. A blank control was treated with an equal amount of organic solvent.

[0050] Using berberine and glyphosate as references, the small cup method was used to determine the effects of these substances on the root length of dicotyledonous weeds Amaranthus retroflexus, Bidens pilosa, Mikania micrantha, Artemisia selengensis, Acer truncatum, Mimosa pudica and monocotyledonous weeds Echinochloa crusgalli, Digitaria sanguinalis, Juncus wickerensis, and Eleocharis chinensis. The plant growth was investigated after 7 days of growth (unit: mm), and the root length inhibition rate was calculated according to the following formula.

[0051] Root length inhibition rate (%) = (control root length - treatment root length) / control root length × 100

[0052] Table 1 Root growth inhibition effect on common dicotyledonous weeds (7 days)

[0053]

[0054] Note: Values ​​in the same column followed by the same lowercase letter indicate no significant difference at the 0.05 level. Berberine is a licensed natural alkaloid herbicide (Patent No. ZL 201110245670.6). Glyphosate was tested at a concentration of 2000 mg / L (common field concentrations are above 5000 mg / L).

[0055] The results showed that the three agents listed in Table 1—hydroxycamptothecin, berberine, and glyphosate—showed significant root growth inhibition against dicotyledonous weeds. At a concentration of 200 mg / L, hydroxycamptothecin showed no significant difference from 200 mg / L berberine and 2000 mg / L glyphosate, achieving a 100% root growth inhibition on dicotyledonous weeds, demonstrating significant root growth inhibition.

[0056] At a concentration of 100 mg / L, hydroxycamptothecin (HCPT) inhibited Amaranthus retroflexus root growth by 94.48%, significantly outperforming berberine. Overall, HCPT was more effective than glyphosate at the same concentration, with no significant difference compared to berberine.

[0057] Table 2 Root growth inhibition effect on common monocotyledonous weeds (7 days)

[0058]

[0059]

[0060] Note: Values ​​in the same column followed by the same lowercase letter indicate no significant difference at the 0.05 level. Berberine is a licensed natural alkaloid herbicide (Patent No. ZL 201110245670.6). Glyphosate was tested at a concentration of 2000 mg / L (common field concentrations are above 5000 mg / L).

[0061] As shown in Table 2, hydroxycamptothecin, berberine, and glyphosate all exhibited significant root growth inhibition against the monocotyledonous weeds barnyard grass, crabgrass, rush, and goosegrass. At a concentration of 200 mg / L, hydroxycamptothecin and berberine exhibited the same 100% root growth inhibition on monocots as glyphosate at 2000 mg / L. There was no statistically significant difference between the three.

[0062] At a concentration of 100 mg / L, hydroxycamptothecin and berberine showed no significant difference in their root growth inhibition against crabgrass. Meanwhile, berberine achieved a 90% inhibition of barnyardgrass root growth, demonstrating excellent root growth inhibition. Overall, hydroxycamptothecin significantly outperformed glyphosate at the same concentration, while showing no significant difference compared to berberine.

[0063] Some photos show Figure 1 and Figure 2 .

[0064] Example 2 Test on fresh weight inhibition of common weeds by hydroxycamptothecin

[0065] The experimental method and design were the same as those in Example 1. The fresh weight of the dicotyledonous weeds Bidens pilosa, Artemisia selengensis, Mimosa pudica, Amaranthus retroflexus, Mikania micrantha, and Acer truncatum and the monocotyledonous weeds Eleocharis chinensis, Digitaria sanguinea, Juncus wicker, and Echinochloa crusgalli were determined by the small cup method. The fresh weight of the aboveground part of the plants (in mg) was investigated after 7 days of growth, and the fresh weight inhibition rate was calculated according to the following formula.

[0066] Fresh weight inhibition rate (%) = (control fresh weight - treatment fresh weight) / control fresh weight × 100

[0067] Table 3 Inhibitory effect on fresh weight of common dicotyledonous weeds (7 days)

[0068]

[0069]

[0070] Note: Values ​​in the same column followed by the same lowercase letter indicate no significant difference at the 0.05 level. Berberine is a licensed natural alkaloid herbicide (Patent No. ZL 201110245670.6). Glyphosate was tested at a concentration of 2000 mg / L (common field concentrations are above 5000 mg / L).

[0071] The results in Table 3 show that the three agents—hydroxycamptothecin, berberine, and glyphosate—all exhibited significant fresh weight inhibition against the dicotyledonous weeds Bidens pilosa, Artichoke, Mimosa pudica, Amaranthus retroflexus, Mikania micrantha, and Atractylodes lancea. At a hydroxycamptothecin concentration of 200 mg / L, the fresh weight inhibition rate against the dicotyledonous weeds reached 100.00%, comparable to the effect of 2000 mg / L glyphosate.

[0072] At a concentration of 100 mg / L, hydroxycamptothecin inhibited the fresh weight growth of Bidens pilosa by 88.23%, which was not significantly different from the effect of berberine at the same concentration. Overall, at the same concentration, hydroxycamptothecin significantly outperformed glyphosate in fresh weight growth inhibition, while the difference with berberine was not significant.

[0073] Table 4 Inhibitory effect on fresh weight of common monocotyledonous weeds (7 days)

[0074]

[0075]

[0076] Note: Values ​​in the same column followed by the same lowercase letter indicate no significant difference at the 0.05 level. Berberine is a licensed natural alkaloid herbicide (Patent No. ZL 201110245670.6). Glyphosate was tested at a concentration of 2000 mg / L (common field concentrations are above 5000 mg / L).

[0077] As shown in Table 4, the three agents—hydroxycamptothecin, berberine, and glyphosate—all demonstrated significant inhibition of the fresh weight growth of the monocotyledonous weeds Goosegrass, Digitaria, Juncus citriodora, and Echinochloa crusgalli. At a concentration of 200 mg / L, hydroxycamptothecin achieved a 100% inhibition of the fresh weight of these monocotyledonous weeds, showing no significant difference from glyphosate at a concentration of 2000 mg / L, demonstrating significant inhibition of the fresh weight of these weeds.

[0078] At a concentration of 100 mg / L, hydroxycamptothecin inhibited the fresh weight of goosegrass and crabgrass by 86.23% and 83.47%, respectively, surpassing berberine at the same concentration. Comprehensive analysis showed that at the same concentration of hydroxycamptothecin, berberine, and glyphosate, hydroxycamptothecin and berberine significantly outperformed glyphosate in fresh weight inhibition, while there was no significant difference between hydroxycamptothecin and berberine, demonstrating excellent herbicidal potential.

[0079] Example 3 Root Growth Inhibition Test of 7-Ethyl-10-Hydroxycamptothecin on Common Weeds

[0080] 7-Ethyl-10-hydroxycamptothecin and berberine were prepared into stock solutions of varying concentrations and then diluted with Hoagland's broth to concentrations of 400 mg / L, 200 mg / L, 100 mg / L, and 50 mg / L. Glyphosate was diluted to 2000 mg / L. A blank control was treated with an equal amount of organic solvent.

[0081] Using berberine and glyphosate as references, the small cup method was used to determine the effects of these substances on the root length of dicotyledonous weeds Amaranthus retroflexus, Bidens pilosa, Mikania micrantha, Acer truncatum, Artemisia selengensis, and Mimosa pudica, and monocotyledonous weeds Echinochloa crusgalli, Digitaria sanguinalis, Juncus wicker, and Eleocharis chinensis. The plant growth was investigated after 7 days of growth (unit: mm), and the root length inhibition rate was calculated according to the following formula.

[0082] Root length inhibition rate (%) = (control root length - treatment root length) / control root length × 100

[0083] Table 5 Root growth inhibition effect on common dicotyledonous weeds (7 days)

[0084]

[0085]

[0086] Note: Values ​​in the same column followed by the same lowercase letter indicate no significant difference at the 0.05 level. Berberine is a licensed natural alkaloid herbicide (Patent No. ZL 201110245670.6). Glyphosate was tested at a concentration of 2000 mg / L (common field concentrations are above 5000 mg / L).

[0087] The results showed that the three agents listed in Table 5—7-ethyl-10-hydroxycamptothecin, berberine, and glyphosate—showed significant root growth inhibition against dicotyledonous weeds. At a concentration of 200 mg / L, 7-ethyl-10-hydroxycamptothecin showed no significant difference from 200 mg / L berberine and 2000 mg / L glyphosate, achieving 100% root growth inhibition against dicotyledonous weeds, demonstrating significant root growth inhibition.

[0088] At a concentration of 100 mg / L, 7-ethyl-10-hydroxycamptothecin (7-ethyl-10-hydroxycamptothecin) inhibited Amaranthus retroflexus root growth by 90.22%, a level comparable to that of berberine. Overall, 7-ethyl-10-hydroxycamptothecin demonstrated superior root growth inhibition compared to glyphosate at the same concentration, with no significant difference compared to berberine.

[0089] Table 6 Root growth inhibition effect on common monocotyledonous weeds (7d)

[0090]

[0091] Note: Values ​​in the same column followed by the same lowercase letter indicate no significant difference at the 0.05 level. Berberine is a licensed natural alkaloid herbicide (Patent No. ZL 201110245670.6). Glyphosate was tested at a concentration of 2000 mg / L (common field concentrations are above 5000 mg / L).

[0092] Experimental data showed that 7-ethyl-10-hydroxycamptothecin, berberine, and glyphosate all exhibited significant root growth inhibition against four monocotyledonous weeds: barnyard grass, crabgrass, rush, and goosegrass. At a concentration of 200 mg / L, 7-ethyl-10-hydroxycamptothecin and berberine exhibited the same complete root growth inhibition as glyphosate at 2000 mg / L, with no statistically significant difference between the three.

[0093] Among them, under the treatment of 100 mg / L concentration, the inhibition rate of 7-ethyl-10-hydroxycamptothecin on the root growth of barnyard grass was 87.45%; comprehensive comparison showed that the root growth inhibition effect of 7-ethyl-10-hydroxycamptothecin was significantly higher than that of glyphosate at the same concentration, and there was no significant difference compared with berberine.

[0094] Some photos show Figure 3 and Figure 4 .

[0095] Example 4: Test on the Fresh Weight Inhibition of Common Weeds by 7-Ethyl-10-Hydroxycamptothecin

[0096] The test method and setting were the same as those in Example 3. The fresh weight of the dicotyledonous weeds Artichoke, Mimosa pudica, Bidens pilosa, Amaranthus retroflexus, and Acer truncatum and the monocotyledonous weeds Goosegrass, Juncus citriodora, Digitaria sanguinalis, and Echinochloa crusgalli were determined by the small cup method. The growth of the plants was investigated after 7 days of growth.

[0097] Fresh weight inhibition rate (%) = (control fresh weight - treatment fresh weight) / control fresh weight × 100

[0098] Table 7 Inhibitory effect on fresh weight of common dicotyledonous weeds (7d)

[0099]

[0100] Note: Values ​​in the same column followed by the same lowercase letter indicate no significant difference at the 0.05 level. Berberine is a licensed natural alkaloid herbicide (Patent No. ZL 201110245670.6). Glyphosate was tested at a concentration of 2000 mg / L (common field concentrations are above 5000 mg / L).

[0101] The data in Table 7 show that the three agents—7-ethyl-10-hydroxycamptothecin, berberine, and glyphosate—all demonstrated significant inhibition of the fresh weight growth of the dicotyledonous weeds Bidens pilosa, Artichoke, Mimosa pudica, Amaranthus retroflexus, Mikania micrantha, and Acer truncatum. At a concentration of 200 mg / L, 7-ethyl-10-hydroxycamptothecin achieved 100% inhibition of the fresh weight growth of these dicotyledonous weeds, comparable to the effect of 2000 mg / L glyphosate.

[0102] At a concentration of 100 mg / L, 7-ethyl-10-hydroxycamptothecin inhibited the fresh weight of Artemisia selengensis by 91.85%, which was not significantly different from the effect of berberine at the same concentration. Overall, at the same concentration, 7-ethyl-10-hydroxycamptothecin significantly outperformed glyphosate in fresh weight inhibition, while the difference with berberine was not significant.

[0103] Table 8 Inhibitory effect on fresh weight of common monocotyledonous weeds (7 days)

[0104]

[0105] Note: Values ​​in the same column followed by the same lowercase letter indicate no significant difference at the 0.05 level. Berberine is a licensed natural alkaloid herbicide (Patent No. ZL 201110245670.6). Glyphosate was tested at a concentration of 2000 mg / L (common field concentrations are above 5000 mg / L).

[0106] The results showed that the three agents shown in Table 8—7-ethyl-10-hydroxycamptothecin, berberine, and glyphosate—all exhibited significant inhibitory effects on the fresh weight growth of the monocotyledonous weeds Goosegrass, Digitaria, Juncus citriodora, and Echinochloa crusgalli. At a concentration of 200 mg / L, 7-ethyl-10-hydroxycamptothecin achieved a 100% inhibition rate on the fresh weight of these monocotyledonous weeds, showing no significant difference from glyphosate at a concentration of 2000 mg / L, demonstrating significant inhibition of weed fresh weight.

[0107] At a concentration of 100 mg / L, 7-ethyl-10-hydroxycamptothecin (7-ethyl-10-hydroxycamptothecin) inhibited the fresh weight of goosegrass by 90.14%, surpassing berberine at the same concentration. Comprehensive analysis showed that at the same concentrations of 7-ethyl-10-hydroxycamptothecin, berberine, and glyphosate, both 7-ethyl-10-hydroxycamptothecin and berberine significantly outperformed glyphosate in inhibiting fresh weight growth, although no statistically significant difference in their inhibitory effects was observed.

[0108] Example 5 Root Growth Inhibition Test of Common Weeds by 9-Aminocamptothecin

[0109] 9-Aminocamptothecin and berberine were prepared into stock solutions of varying concentrations and then diluted with Hoagland's broth to concentrations of 400 mg / L, 200 mg / L, 100 mg / L, and 50 mg / L. Glyphosate was diluted to 2000 mg / L. A blank control was treated with an equal amount of organic solvent.

[0110] Using berberine and glyphosate as references, the small cup method was used to determine the effects of these substances on the root length of dicotyledonous weeds Amaranthus retroflexus, Bidens pilosa, Mikania micrantha, Acer truncatum, Artemisia selengensis, and Mimosa pudica, and monocotyledonous weeds Echinochloa crusgalli, Digitaria sanguinalis, Juncus wicker, and Eleocharis chinensis. The plant growth was investigated after 7 days of growth (unit: mm), and the root length inhibition rate was calculated according to the following formula.

[0111] Root length inhibition rate (%) = (control root length - treatment root length) / control root length × 100

[0112] Table 9 Root growth inhibition effect on common dicotyledonous weeds (7d)

[0113]

[0114] Note: Values ​​in the same column followed by the same lowercase letter indicate no significant difference at the 0.05 level. Berberine is a licensed natural alkaloid herbicide (Patent No. ZL 201110245670.6). Glyphosate was tested at a concentration of 2000 mg / L (common field concentrations are above 5000 mg / L).

[0115] According to the data in Table 9, 9-aminocamptothecin, berberine, and glyphosate exhibited significant root growth inhibition against dicotyledonous weeds. At a concentration of 200 mg / L, 9-aminocamptothecin showed no significant difference from 200 mg / L berberine and 2000 mg / L glyphosate, achieving 100% root growth inhibition against dicotyledonous weeds, demonstrating significant root growth inhibition.

[0116] At a concentration of 100 mg / L, 9-aminocamptothecin inhibited root growth by 80% across all dicotyledonous weeds, demonstrating excellent root growth inhibition. Specifically, it inhibited root growth by 93.55% against Amaranthus retroflexus, exceeding the inhibitory effect of berberine at the same concentration. Overall, 9-aminocamptothecin was more effective at inhibiting root growth than glyphosate at the same concentration, with no significant difference compared to berberine.

[0117] Table 10 Root growth inhibition effect on common monocotyledonous weeds (7d)

[0118]

[0119] Note: Values ​​in the same column followed by the same lowercase letter indicate no significant difference at the 0.05 level. Berberine is a licensed natural alkaloid herbicide (Patent No. ZL 201110245670.6). Glyphosate was tested at a concentration of 2000 mg / L (common field concentrations are above 5000 mg / L).

[0120] The results showed that the three agents shown in Table 10—9-aminocamptothecin, berberine, and glyphosate—all exhibited significant root growth inhibition against the monocotyledonous weeds barnyard grass, crabgrass, rush, and goosegrass. At a concentration of 200 mg / L, 9-aminocamptothecin and berberine exhibited the same 100% root growth inhibition on monocots as glyphosate at 2000 mg / L, with no statistically significant differences observed among the three agents.

[0121] At a concentration of 100 mg / L, 9-aminocamptothecin inhibited barnyard grass root growth by 89.03% and crabgrass root growth by 86.22%, exceeding the inhibition rate of berberine at the same concentration. Overall, 9-aminocamptothecin significantly outperformed glyphosate at the same concentration, but showed no significant difference compared to berberine.

[0122] Some photos show Figure 5 and Figure 6 .

[0123] Example 6 9-aminocamptothecin fresh weight inhibition test on common weeds

[0124] The experimental method and design were the same as those in Example 1. The fresh weight of these substances on the dicotyledonous weeds Artemisia selengensis, Bidens pilosa, Mimosa pudica, Atractylodes lancea, and Amaranthus retroflexus and the monocotyledonous weeds Juncus wickerensis, Goosegrass, Digitaria sanguinea, and Echinochloa crus-galli was determined by the small cup method. After 7 days of growth, the fresh weight of the above-ground part of the plants was investigated (in mg), and the fresh weight inhibition rate was calculated according to the following formula.

[0125] Fresh weight inhibition rate (%) = (control fresh weight - treatment fresh weight) / control fresh weight × 100

[0126] Table 11 Inhibitory effect on fresh weight of common dicotyledonous weeds (7 days)

[0127]

[0128] Note: Values ​​in the same column followed by the same lowercase letter indicate no significant difference at the 0.05 level. Berberine is a licensed natural alkaloid herbicide (Patent No. ZL 201110245670.6). Glyphosate was tested at a concentration of 2000 mg / L (common field concentrations are above 5000 mg / L).

[0129] The results showed that the three agents shown in Table 11—9-aminocamptothecin, berberine, and glyphosate—all exhibited significant fresh weight inhibition against the dicotyledonous weeds Bidens pilosa, Artichoke, Mimosa pudica, Amaranthus retroflexus, Mikania micrantha, and Atractylodes lancea. At a concentration of 200 mg / L, 9-aminocamptothecin achieved 100% fresh weight inhibition against these weeds, comparable to the effect of 2000 mg / L glyphosate.

[0130] At a concentration of 100 mg / L, 9-aminocamptothecin inhibited the fresh weight of Artemisia selengensis and Bidens pilosa by 93.25% and 89.36%, respectively, both exceeding the effect of berberine at the same concentration, demonstrating excellent fresh weight inhibitory activity. Overall, at the same concentration, 9-aminocamptothecin significantly outperformed glyphosate in fresh weight inhibition, while the difference with berberine was not significant.

[0131] Table 12 Inhibitory effect on fresh weight of common monocotyledonous weeds (7 days)

[0132]

[0133] Note: Values ​​in the same column followed by the same lowercase letter indicate no significant difference at the 0.05 level. Berberine is a licensed natural alkaloid herbicide (Patent No. ZL 201110245670.6). Glyphosate was tested at a concentration of 2000 mg / L (common field concentrations are above 5000 mg / L).

[0134] The data in Table 12 show that the three agents—9-aminocamptothecin, berberine, and glyphosate—all demonstrated significant inhibition of the fresh weight growth of the monocotyledonous weeds Juncus citriodora, Goosegrass, Echinochloa crusgalli, and Digitaria sanguinalis. At a concentration of 200 mg / L, 9-aminocamptothecin achieved a 100% inhibition of the fresh weight of these monocotyledonous weeds, showing no significant difference from glyphosate at a concentration of 2000 mg / L, demonstrating significant inhibition of the fresh weight of these weeds.

[0135] At a concentration of 100 mg / L, 9-aminocamptothecin inhibited the fresh weight of Juncus citriodora, Goosegrass, and Digitaria sanguine by 86.86%, 84.94%, and 79.24%, respectively, surpassing berberine at the same concentration. Comprehensive analysis revealed that at the same concentrations of 9-aminocamptothecin, berberine, and glyphosate, 9-aminocamptothecin and berberine significantly outperformed glyphosate in fresh weight inhibition, while no significant difference was observed between 9-aminocamptothecin and berberine, demonstrating synergistic herbicidal potential.

[0136] Comparative Example 1: Very low herbicidal activity of camptothecin

[0137] (1) Test on root growth inhibition of common weeds by homocamptothecin

[0138] Homocamptothecin was prepared into a stock solution of varying concentrations and then diluted with Hoagland's broth to concentrations of 400 mg / L, 200 mg / L, 100 mg / L, and 50 mg / L. Glyphosate was diluted to 2000 mg / L. A blank control was treated with an equal amount of organic solvent.

[0139] Using glyphosate as a reference, the small cup method was used to determine the effects of these substances on the root length of the dicotyledonous weeds Atractylodes macrocephala, Mikania micrantha, Atractylodes macrocephala, Amaranthus retroflexus, Bidens pilosa, Artemisia selengensis, and Mimosa pudica, and the monocotyledonous weeds Echinochloa crusgalli, Digitaria sanguinea, Juncus wicker, and Eleocharis chinensis. The plant growth was investigated after 7 days of growth (unit: mm), and the root length inhibition rate was calculated according to the following formula.

[0140] Root length inhibition rate (%) = (control root length - treatment root length) / control root length × 100

[0141] Table 13 Root growth inhibition effect on common dicotyledonous weeds (7d)

[0142]

[0143] Note: Values ​​in the same column followed by the same lowercase letter are not significantly different at the 0.05 level. Glyphosate concentration tested was 2000 mg / L (common field concentrations are above 5000 mg / L).

[0144] According to the data in Table 13, at a concentration of 100 mg / L, the root length inhibition effect of homocamptothecin on dicotyledonous weeds was 0; when the concentration was increased to 400 mg / L, the fresh weight inhibition rate of homocamptothecin on dicotyledonous weeds reached a maximum of 7.42%, and the fresh weight inhibition rate on Mimosa pudica was the lowest, only 5.26%; overall, the root length inhibition effect of homocamptothecin on dicotyledonous weeds was significantly lower than that of glyphosate, and its root length inhibition activity was poor.

[0145] Table 14 Root growth inhibition effect on common monocotyledonous weeds (7d)

[0146]

[0147]

[0148] Note: Values ​​in the same column followed by the same lowercase letter are not significantly different at the 0.05 level. Glyphosate concentration tested was 2000 mg / L (common field concentrations are above 5000 mg / L).

[0149] The results showed that glyphosate, even at concentrations lower than those observed in the field, still achieved 100% root growth inhibition against monocotyledonous weeds. However, at a concentration of 400 mg / L, homocamptothecin only inhibited root growth by a maximum of 5.37%, a significant difference in effectiveness. Overall, homocamptothecin demonstrated a poorer root growth inhibition effect and lacked significant herbicidal activity.

[0150] (II) Test on fresh weight inhibition of common weeds by homocamptothecin

[0151] The experimental method and design were the same as above. The small cup method was used to determine the fresh weight of these substances on dicotyledonous weeds Bidens pilosa, Mikania micrantha, Artemisia selengensis, Amaranthus retroflexus, Mimosa pudica and monocotyledonous weeds Juncus wicker, Digitaria sanguinea, Echinochloa crusgalli, and Eleocharis chinensis. After 7 days of growth, the fresh weight of the aboveground part of the plants was investigated (in mg), and the fresh weight inhibition rate was calculated according to the following formula.

[0152] Fresh weight inhibition rate (%) = (control fresh weight - treatment fresh weight) / control fresh weight × 100

[0153] Table 15 Inhibitory effect on fresh weight of common dicotyledonous weeds (7d)

[0154]

[0155] Note: Values ​​in the same column followed by the same lowercase letter are not significantly different at the 0.05 level. Glyphosate concentration tested was 2000 mg / L (common field concentrations are above 5000 mg / L).

[0156] The results showed that glyphosate exhibited significant fresh weight inhibition against the dicotyledonous weeds Bidens pilosa, Mikania micrantha, Artemisia selengensis, Amaranthus chinensis, Amaranthus retroflexus, and Mimosa pudica, with fresh weight inhibition rates reaching 100%. Homocamptothecin, however, had no significant fresh weight inhibition effect on these dicotyledonous weeds. At a concentration of 400 mg / L, homocamptothecin had the highest fresh weight inhibition rate against Bidens pilosa, at only 6.20%. Overall, the fresh weight inhibition effects of homocamptothecin and glyphosate were significantly different.

[0157] Table 16 Inhibitory effect on fresh weight of common monocotyledonous weeds (7d)

[0158]

[0159] Note: Values ​​in the same column followed by the same lowercase letter are not significantly different at the 0.05 level. Glyphosate concentration tested was 2000 mg / L (common field concentrations are above 5000 mg / L).

[0160] The data in Table 16 show that glyphosate exhibited significant fresh weight inhibition against the monocotyledonous weeds Juncus citriodora, Digitaria sanguinalis, Echinochloa crusgalli, and Goosegrass. Homocamptothecin, however, exhibited less effective fresh weight inhibition against these monocotyledonous weeds. At a concentration of 400 mg / L, the highest fresh weight inhibition rate for these four weeds reached 7.16%, while the lowest was only 4.45%. Overall, the fresh weight inhibition effect of homocamptothecin was negligible and low.

[0161] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. Application of camptothecin derivatives in herbicides, wherein the camptothecin derivatives are any one or more of hydroxycamptothecin, 7-ethyl-10-hydroxycamptothecin, and 9-aminocamptothecin.

2. Use of a camptothecin derivative as or in the preparation of a herbicide, wherein the camptothecin derivative is any one or more of hydroxycamptothecin, 7-ethyl-10-hydroxycamptothecin, and 9-aminocamptothecin.

3. Application of plant extracts rich in camptothecin derivatives in weed control, wherein the camptothecin derivatives are any one or more of hydroxycamptothecin, 7-ethyl-10-hydroxycamptothecin, and 9-aminocamptothecin.

4. Use of a plant extract rich in camptothecin derivatives as or in the preparation of a herbicide, wherein the camptothecin derivative is any one or more of hydroxycamptothecin, 7-ethyl-10-hydroxycamptothecin, and 9-aminocamptothecin.

5. The use according to claim 3 or 4, characterized in that The said rich camptothecin derivative means that the main active substance is camptothecin derivative.

6. The use according to claim 3 or 4, characterized in that The plant extract is a camptotheca acuminata extract.

7. The use according to claim 6, characterized in that The camptotheca acuminata extract is one or more of a camptotheca acuminata seed extract, a camptotheca acuminata root extract and a camptotheca acuminata bark extract.

8. A herbicide, characterized in that The herbicidal active ingredient comprises camptothecin derivatives or camptothecin extracts containing camptothecin derivatives. The camptothecin derivatives are any one or more of hydroxycamptothecin, 7-ethyl-10-hydroxycamptothecin and 9-aminocamptothecin.

9. A method for controlling weeds, characterized in that: Camptothecin derivatives or herbicides containing camptothecin derivatives are used to control weeds. The camptothecin derivatives are any one or more of hydroxycamptothecin, 7-ethyl-10-hydroxycamptothecin and 9-aminocamptothecin.

10. The use according to any one of claims 1 to 4, the herbicide according to claim 8, or the method according to claim 9, characterized in that: The grass is any one or more of Amaranthus retroflexus, Bidens pilosa, Mikania micrantha, Artemisia selengensis, Acer truncatum, Mimosa pudica, Echinochloa crusgalli, Digitaria sanguinea, Juncus wicker and Goosegrass.

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