A fungicidal composition containing a new alstoniaspermatine derivative and rheum anthraquinones

Abstract

The application belongs to the field of agricultural fungicide compound, discloses a composition containing new white folium altheae alkaloid derivative Z-24 and anthraquinone components (emodin, emodin methyl ether, chrysophanol, aloe emodin) in rhubarb and mixed concentration thereof. The application of the composition in preventing and treating plant diseases caused by rhizoctonia solani, sclerotinia sclerotiorum, fusarium graminearum, botrytis cinerea, pyricularia oryzae and phytophthora capsici is disclosed, and the mass percentage of new white folium altheae alkaloid derivative Z-24 and anthraquinone components is 1:500, 1:100, 1:50 or 1:25. The fungicidal composition disclosed in the application has the advantages of wide fungicidal spectrum, low toxicity, effective delay of drug resistance of plant pathogens and the like, and has the value of further research and development.

Description

Technical Field

[0001] This invention relates to the field of agricultural fungicides, with active component A: a derivative of neobaiye tunic alkaloid, and active component B: anthraquinone compounds from the traditional Chinese medicine rhubarb, including emodin, aloe-emodin, emodin methyl ether, and chrysophanol, as active ingredients. This composition is used to control diseases caused by plant pathogenic fungi such as Rhizoctonia solani, Sclerotinia sclerotiorum, Botrytis cinerea, Fusarium graminearum, Rice blast fungus, and Phytophthora capsici. Background Technology

[0002] my country is a major agricultural producer, but crop diseases are frequent, severe, and widespread. More than 1,600 harmful organisms appear annually, with nearly 100 causing serious damage to crops. Major crop diseases such as wheat scab, rice blast, and potato late blight seriously threaten stable food production. Among these, 70%-80% of crop diseases are caused by plant pathogenic fungi. The potato late blight pandemic in Ireland between 1845 and 1852 resulted in the deaths of over one million people; the rice sesame spot pandemic in Bengal in 1943 led to the starvation of approximately two million people. Even with today's advanced technology, the losses caused by plant diseases to agriculture remain staggering. The invasive nature of harmful species and their rapid spread exacerbate the severity of plant diseases. The use of chemical reagents has always been the main means of controlling plant fungal diseases. However, the global bans and restrictions on highly toxic pesticides and the continuous development of drug resistance in various plant pathogenic fungi have led researchers to pay increasing attention to agricultural fungicides with low toxicity, safety, and good environmental compatibility. The combination of fungicides with different mechanisms of action has many advantages, such as reducing the amount of chemical fungicides used, broadening the fungicidal spectrum, reducing toxicity, and reducing the emergence of drug resistance. Therefore, it has become an important means of solving plant diseases.

[0003] Neocryptolepine (5-methyl-5H-indole[2,3-b]-quinoline) is an isomer of cryptocryptolepine, with a linearly fused four-membered heterocycle containing an indole ring and a quinoline ring. It is a natural alkaloid isolated from the African climbing plant Cryptopissinensis (Lour.) Merr., and is a traditional African medicine. It has a variety of biological activities, including antitumor, antibacterial, antifungal, and antiparasitic activities. Due to its diverse activities and high content in the plant, it has become a natural source lead structure that is widely modified and optimized by medicinal chemists.

[0004] Rhubarb (Rheum palmatum L.) has a long history of medicinal use and is one of my country's famous specialty medicinal materials. It is a typical representative of Chinese medicinal materials with multiple functions, varieties, and origins. As a major medicinal material and authentic medicinal material in Gansu Province, its anthraquinone compounds are the main research object. Modern pharmacological studies have shown that rhubarb has a variety of pharmacological activities, including antifungal, antitumor, and antioxidant effects. For example, anthraquinone derivatives have shown activity against methicillin-resistant Staphylococcus aureus (MIC = 4 μg / mL, rhein), vancomycin-resistant Enterococcus (MIC = 2-8 μg / mL, cationic anthraquinone derivatives), Escherichia coli (MIC = 16 μg / mL, rhein), Candida albicans (MIC = 50 μg / mL, rhubarb extract), and Staphylococcus aureus (EC). 50 =8.28 μg / mL, rhein), Erythrina variegata (EC) 50 =4.7 μg / mL, rhein, EC 50 =0.48μg / mL, emodin methyl ether, etc., all have strong inhibitory activity, among which the antibacterial activity against drug-resistant Staphylococcus aureus has been studied most extensively; in addition, it also has growth-inhibiting or killing effects on cotton bollworm, twisted bloodworm, etc. However, current research on rhubarb anthraquinone compounds mainly focuses on iatrogenic pathogens, and there are few studies on plant pathogens. According to existing research, the natural anthraquinone derivatives contained in rhubarb have a narrow antibacterial spectrum against plant pathogenic fungi, with general antibacterial activity against most plant pathogenic fungi, and there are solubility problems at high concentrations. Based on this, this study uses the new white vine alkaloid derivative Z-24 as the main agent and the anthraquinone components in rhubarb as the excipient to conduct a synergistic effect study on common plant pathogenic fungi such as Rhizoctonia solani, Sclerotinia sclerotiorum, Botrytis cinerea, Fusarium graminearum, Rice blast fungus, and Phytophthora capsici, to improve their antibacterial activity and reduce the dosage and toxicity of the new white vine alkaloid derivative Z-24. Summary of the Invention

[0005] The purpose of this invention is to provide a fungicide composition containing a derivative of neomycete alkaloid and anthraquinone compounds for the prevention and control of plant diseases caused by Rhizoctonia solani, Sclerotinia sclerotiorum, Botrytis cinerea, Fusarium graminearum, Rice blast fungus, Phytophthora capsici, etc.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A bactericide composition containing a neo-whiteleaf alkaloid derivative and anthraquinone compounds, comprising active component A and active component B, wherein active component A is a neo-whiteleaf alkaloid derivative Z-24, and active component B is anthraquinone compounds: emodin, aloe-emodin, emodin methyl ether, and chrysophanol.

[0008] The fungicide composition provided by this invention, as an agricultural fungicide, has the following advantages:

[0009] 1) The bactericidal composition provided by the present invention can reduce the amount of the main ingredient, the derivative of the alkaloid Z-24, thereby reducing the cost of pesticides.

[0010] 2) The bactericidal composition provided by the present invention improves the control effect of abundant natural anthraquinone compounds on plant pathogens, and has a significant synergistic effect with Z-24 in a certain compounding ratio.

[0011] 3) The active ingredients in the bactericidal composition provided by the present invention have different mechanisms of action, which can effectively delay and reduce the development of drug resistance in plant pathogens and enhance the control effect. Detailed Implementation

[0012] To better understand the essence of the present invention, the following specific embodiments are provided, but the present invention is not limited to these embodiments. In these embodiments, unless otherwise stated, all percentages are weight percentages.

[0013] Example 1: A bactericide composition containing a neo-white vine alkaloid derivative Z-24 and anthraquinone compounds, comprising active component A and active component B (as shown in Figure 1), wherein active component A is a neo-white vine alkaloid derivative Z-24, and active component B is anthraquinone components from rhubarb, including emodin, emodin methyl ether, chrysophanol, and aloe-emodin.

[0014]

[0015] Example 2: Indoor Antibacterial Activity Determination of Plant Pathogenic Fungi

[0016] The plant pathogenic fungi used in this experiment were strains preserved at 4℃ in the laboratory. All plant pathogenic fungi used in the laboratory were cultured on potato agar-dextrose medium (PDA). The PDA medium formula was: 200g potato (peeled), 20g glucose, 15g agar, and 1000mL distilled water. The antibacterial activity was determined using the mycelial growth rate method.

[0017] PDA culture medium preparation method: Wash and peel potatoes, weigh 200g and cut into small pieces, add water and boil until soft (boil for 20-30 minutes, until it can be pierced by a glass rod), filter through four layers of gauze into a beaker and add distilled water to 1000mL, add 15-20g agar according to experimental needs, add 20g glucose, stir to dissolve fully, dispense into Erlenmeyer flasks, sterilize at 121℃ for 20 minutes, and set aside.

[0018] Experimental methods

[0019] 1) Mycelial growth rate method.

[0020] 1. First, activate the plant pathogens by culturing them on a PDA plate at 25°C for 3-6 days.

[0021] 2. Melt the PDA culture medium by heating, cool it to 45-50℃, and add different concentrations of bactericidal composition to prepare drug-loaded plates.

[0022] 3. Using aseptic techniques, use a punch to make round mycelial cakes (5 mm in diameter) at the edge of the mycelium of each strain after 3-6 days of culture (with the growth conditions as uniform as possible). Then, use an inoculation needle to pick them up and transfer them to the center of the drug-containing plate. Finally, invert the petri dish and incubate it in an incubator (25°C).

[0023] 4. After the blank control group has fully grown, observe and measure the growth of mycelia, and use the cross-cross method to measure the diameter and process the data to calculate the percentages of growth inhibition (PGI).

[0024] 5. Mycelial growth inhibition rate (%) = (Control mycelial diameter - Treated mycelial diameter) / (Control mycelial diameter - Mycelial cake diameter) × 100

[0025] 6. Repeat each treatment 3 times.

[0026] Example 3: Indoor activity determination of a mixture of neomycetin derivative Z-24 and active component B on six plant pathogens.

[0027] The synergistic effect of fungicides when mixed is calculated using Abbott's (1925) formula, which determines the coefficient of synergistic effect after mixing different agents.

[0028]

[0029] In the formula, PGI1 and PGI2 represent the inhibition rates of Z-24 (1) and anthraquinone components (2) in rhubarb on mycelial growth, respectively. OPGI and EPGI represent the actual observed inhibition rate of the mixture on mycelial growth and the theoretical inhibition rate of the mixture on mycelial growth, respectively. AI is the Abbott index. AI ≥ 1.5 indicates synergistic effect; AI < 0.5 indicates antagonism; AI between 0.5 and 1.5 indicates additive effect.

[0030] Table 1. Indoor virulence synergistic effect of Z-24 and active component B on *Bacillus oryzae*.

[0031]

[0032]

[0033] As shown in Table 1, when the mass ratio of Z-24 and active component B is 1:25, it has a significant synergistic effect on rice blast fungus. The measured values ​​of the inhibition rate of the mixture on the mycelial growth of rice blast fungus are all around 90%.

[0034] Table 2. Indoor virulence synergistic effect of Z-24 and active component B combination on Fusarium graminearum

[0035]

[0036] Table 2 shows that Z-24 and active component B exhibit significant synergistic effects against Fusarium graminearum pathogens at mass ratios of 1:25, 1:50, and 1:100. At mass ratios of 1:25 and 1:50, the synergistic effect between Z-24 and emodin methyl ether is most pronounced, with AI values ​​of 5.32 and 10.36, respectively.

[0037] Table 3. Enhanced in vitro toxicity of Botrytis cinerea by the combination of Z-24 and active ingredient B.

[0038]

[0039]

[0040] As shown in Table 3, Z-24 exhibits significant synergistic effects against Botrytis cinerea when mixed with emodin and chrysophanol in active component B at mass ratios of 1:500 and 1:2500, respectively, with AI values ​​of 2.03, 3.11, 2.81, and 6.72.

[0041] Table 4. Indoor virulence synergistic effect of Z-24 and active component B combination on Rhizoctonia solani.

[0042]

[0043] As shown in Table 4, Z-24 and active component B have an additive effect at the set ratio, with no synergistic effect.

[0044] Table 5. Indoor virulence synergistic effect of Z-24 and active component B on *Sclerotinia sclerotiorum*.

[0045]

[0046]

[0047] As shown in Table 5, Z-24 and active component B have an additive effect at the set ratios, with only Z-24 and rhein showing a synergistic effect on Sclerotinia sclerotiorum at a ratio of 1:100.

[0048] Table 6. Indoor virulence synergistic effect of Z-24 and active component B combination on *Phytophthora capsici*.

[0049]

[0050] As shown in Table 6, Z-24 and active component B have additive or antagonistic effects at the set ratios, with no synergistic effect.

[0051] In summary, Z-24 and anthraquinone components in rhubarb, at appropriate ratios, exhibit significant synergistic effects against some plant pathogens, such as *Botrytis cinerea*, *Fusarium graminearum*, and *Oryza sativa*, but no synergistic effect was observed against *Rhizoctonia solani*, *Sclerotinia sclerotiorum*, and *Phytophthora capsici*. Among these, at a ratio of 1:50, the Z-24-emodin methyl ether combination showed the most significant synergistic effect, with an AI value as high as 10.36 against *Fusarium graminearum*. Furthermore, the actual observed inhibition rates of *Oryza sativa* mycelial growth by Z-24 combined with emodin, emodin methyl ether, and aloe-emodin at a ratio of 1:25 were all around 90%.

[0052] The bactericidal composition of the present invention, containing the neo-whiteleaf alkaloid derivative Z-24, emodin, emodin methyl ether, aloe-emodin, and chrysophanol, can significantly reduce the dosage of neo-whiteleaf alkaloid derivative Z-24 and improve the antibacterial activity of anthraquinone compounds. Therefore, the bactericidal composition of the present invention has value for further research and development.

Claims

1. A bactericidal composition containing a neo-white vine alkaloid derivative Z-24 and rhubarb anthraquinone components, characterized in that, The active ingredients of the bactericidal composition are a new white vine alkaloid derivative Z-24 and anthraquinone components of rhubarb; the molecular structure of the new white vine alkaloid derivative Z-24 is as follows: The anthraquinone components of rhubarb are any one of aloe-emodin, emodin, emodin methyl ether, and chrysophanol. ； The mass ratio of the new white vine alkaloid derivative Z-24 to aloe-emodin is 1:25 and 1:50; The mass ratios of the new white vine alkaloid derivative Z-24 to emodin are 1:25, 1:50, and 1:500; The mass ratio of the new white vine alkaloid derivative Z-24 to rhein methyl ether is 1:25 and 1:50; The mass ratio of the new white cyperine derivative Z-24 to rhein is 1:25, 1:50, and 1:100.

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