CN111713503A - Application of two isoflavone compounds in preventing and treating plant diseases - Google Patents

Abstract

The invention relates to application of two isoflavone compounds in preventing and treating plant diseases, belonging to the technical field of plant source bactericides. The compounds are respectively 4-O-methyl glabridin and glabridin B, which are isolated from Glycyrrhiza plants, and can be prepared by chemical synthesis or biosynthesis. The compound can effectively inhibit sclerotinia sclerotiorum, fusarium graminearum, botrytis cinerea, colletotrichum barbarum, rhizoctonia solani, fusarium oxysporum, pyricularia oryzae and rice bacterial blight, and the plant source bactericide prepared by processing the compound as an active ingredient can be used for preventing and treating plant diseases caused by the pathogenic bacteria. The technical scheme of the invention has the characteristics of environmental friendliness, relative safety to non-target organisms and the like, and can relieve the problem of drug resistance by being alternately used with the existing bactericide.

Description

Application of two isoflavone compounds in preventing and treating plant diseases

Technical Field

The invention belongs to the technical field of plant-derived bactericides, and particularly relates to application of two isoflavone compounds in preventing and treating plant diseases.

Background

Plant diseases are seriously harmful to agricultural production, and cause huge economic losses in the world every year. Chemical control is an important means for controlling plant diseases, but long-term use of chemical pesticides causes serious environmental problems and drug resistance problems, so that development of novel green control agents for alternative use is urgently needed.

4’-OBoth glabridin and glabridin B are isoflavonoids, and are mainly extracted from Glycyrrhiza (Leguminosae) Glycyrrhiza (Leguminosae)GlycyrrhizaLinn.) from plants. At present, the use of the two isoflavones mainly focuses on treating diabetes, hyperlipidemia, hypertension (chinese patent CN1777420A, world patent WO2005011672a 1), anxiety (Ambawade S D, et al, 2001), tumors (Lee C K, et al, 2007), and the like, and can also be used for whitening (Nerya O, et al, 2003).

At present, the research on the two isoflavones in the aspect of resisting pathogenic microorganisms mainly focuses on resisting the pathogenic microorganisms of human bodies, and the searched literature shows that 4-OGlabridin has activity of inhibiting proliferation of Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Candida albicans, Escherichia coli, Aspergillus niger, Trichophyton mentagrophytes (Li W, et al, 1998); the liquiritigenin B has activity of inhibiting proliferation of influenza virus (Grienke U, et al., 2013), Candida albicans (Fatim A, et al., 2009), and tubercle bacillus (Gupta V K, et al., 2008). However, there are no reports on the use of the two isoflavones in resisting phytopathogens.

Disclosure of Invention

Aiming at the defects, the invention provides the application of two isoflavone compounds in preventing and treating plant diseases.

The invention is realized by the following technical scheme.

The isoflavone compound can be purchased from the market, can be extracted and separated from glycyrrhiza plants such as liquorice, glycyrrhiza glabra, glycyrrhiza uralensis and the like, and can be prepared by a chemical synthesis method or a biosynthesis method.

The isoflavone compound can be used as an active ingredient and a pesticide auxiliary agent to be processed into any formulation allowed by pesticides.

The dosage forms comprise powder, wettable powder, soluble powder, granules, aqueous solution, missible oil, aqueous emulsion, microemulsion, water dispersible granules, suspending agent, smoke agent, sustained release agent, seed coating agent or oil agent.

The application refers to the application of the composition in preventing and treating diseases caused by sclerotinia sclerotiorum, fusarium graminearum, botrytis cinerea, colletotrichum barbarum, rhizoctonia solani, fusarium oxysporum, pyricularia oryzae and rice bacterial blight.

The research proves that the two isoflavone compounds have obvious bacteriostatic activity on sclerotinia sclerotiorum, fusarium graminearum, botrytis cinerea, colletotrichum barbarum, rhizoctonia solani, fusarium oxysporum, pyricularia oryzae and rice bacterial leaf blight, and can be developed into a control medicament to be alternately used with the conventional medicament, so that the problems of environmental pollution and drug resistance are relieved.

Detailed Description

The following examples further illustrate the present invention in detail, but the present invention is not limited to the contents contained in the following examples.

Example 1:

pulverizing dried Glycyrrhrizae radix 5kg, extracting with 80% ethanol under reflux for 3 times, mixing extractive solutions, concentrating under reduced pressure until no alcohol smell exists, dissolving the obtained extract with 5L water, extracting with equal volume of ethyl acetate for 3 times, and concentrating the extractive solution to dryness to obtain 200g of ethyl acetate part extract. Subjecting the extract to silica gel column chromatography, and performing gradient elution with petroleum ether-ethyl acetate system (100: 0-0: 100). Wherein the component eluted by petroleum ether-ethyl acetate (50: 1) is repeatedly separated and purified by silica gel column chromatography and recrystallized by methanol to obtain the monomer compound 4-O-methyl glabridin (21 mg) and liquiritigenin B (16 mg).

Example 2:

isoflavone suspending agent with 20% concentration of effective components, wherein the prescription composition takes 100g of sample as an example: 20g of isoflavone compound, 5g of methylene dinaphthalene sodium sulfonate serving as a dispersing agent, 3g of sodium lignin sulfate serving as a wetting agent, 0.5g of benzoic acid serving as a stabilizing agent, 6g of ethylene glycol serving as an anti-freezing agent, 2g of tributyl phosphate serving as an antifoaming agent, 0.5g of potassium sorbate serving as a preservative, 0.5g of xanthan gum serving as a thickening agent and 62.5g of soft water.

The preparation process comprises the following steps: adding isoflavone compounds, sodium methylene dinaphthalene sulfonate, sodium lignin sulfate, benzoic acid, ethylene glycol, potassium sorbate and soft water in a certain amount into a shearing machine, and shearing for 30 minutes; using a sand mill to sand and cut the material for 3 times, and adding tributyl phosphate with a metered amount while grinding; adding xanthan gum into the ground materials, shearing for 20 minutes, and packaging after the xanthan gum is detected to be qualified.

Example 3:

isoflavone wettable powder with the effective component concentration of 25 percent takes 100g of samples as an example: 25g of isoflavone compound, 3g of BX nekal, 0.5g of hydroxypropyl methylcellulose serving as a suspending agent, 3g of sodium dodecyl benzene sulfonate serving as a wetting agent and 68.5g of kaolin serving as a carrier.

The preparation process comprises the following steps: mixing BX nekal, hydroxypropyl methylcellulose and sodium dodecyl benzene sulfonate according to the measured number, grinding and crushing, adding isoflavone compounds according to the measured number to obtain active ingredient powder, adding kaolin according to the measured number, uniformly mixing, and sieving by a 250-mesh sieve to obtain the wettable powder.

Example 4:

isoflavone water dispersible granule with effective component concentration of 50 percent, the prescription composition takes 100g of sample as an example: 50g of isoflavone compound, 5g of dispersant sodium lignosulfonate, 4.5g of wetting agent sodium dodecyl sulfate, 3g of disintegrant starch, 3.5g of stabilizer benzoic acid, 20003 g of binder polyethylene glycol and 31g of extender kaolin.

The preparation process comprises the following steps: the isoflavone compound, sodium lignosulphonate, sodium dodecyl sulfate, starch, benzoic acid and kaolin are uniformly mixed according to the measured amount, the mixture is crushed by a jet mill to prepare mother powder, the mother powder is uniformly mixed with polyethylene glycol 2000, and the mixture is granulated, dried and screened to prepare the water dispersible granule.

Example 5:

the activities of two isoflavone compounds on plant pathogenic fungi and bacteria are respectively measured by adopting a hyphal growth rate method and a turbidimetric method:

determining the fungal subject comprises Sclerotinia sclerotiorum (A)Sclerotinia sclerotiorum) Wheat scab bacteria (1)Fusarium graminearum) Cucumber Botrytis cinerea: (Botrytis cinerea) Goji barnyard fungus (B)Colletotrichum gloeosporioides) Rhizoctonia solani (C. solani)Rhizoctonia solani) Banana wilt bacteria (Fusarium oxysporum) And Pyricularia oryzae: (Magnaporthe oryzae) The bacterial object is rice bacterial blight (Xanthomonas oryzaepv.oryzae）。

Two kinds of isoflavones prepared in example 1 were dissolved in DMSO to prepare a stock solution having a concentration of 10000. mu.g/mL, and were subjected to gradient dilution with DMSO.

Hypha growth rate method: adding compound solution or DMSO with equal volume into PSA culture medium to obtain medicated plate. A5 mm diameter plate was punched from the edge of the vigorously growing colony and inoculated into the middle of the plate, incubated at 25 ℃ until the colony was nearly full of the plate, and the colony diameter was measured by the cross method (minus the 5mm plate diameter). Inhibition (%) = (solvent control colony diameter-agent-treated colony diameter)/solvent control colony diameter × 100.

Turbidimetry: adding compound solution or DMSO with equal volume into NB culture solution to obtain culture solution containing medicine. Bacterial liquid OD pre-cultured to logarithmic phase by using spectrophotometer₆₀₀The value is adjusted to 0.02 and added into the drug-containing culture solution according to the proportion of 1: 200. The control was grown to logarithmic growth phase by shaking at 175rpm at 28 ℃ and OD was measured with a spectrophotometer₆₀₀And the inhibition rate was calculated. Inhibition (%) = (control OD)₆₀₀value-Add medicine and handle OD₆₀₀Value)/control OD₆₀₀Value × 100.

Calculating EC according to inhibition rates of different concentrations₅₀The value is obtained.

And (3) test results: fromAs can be seen in Table 1, the two isoflavonoids have better bacteriostatic activity on all the test strains, wherein 4-OThe bacteriostatic activity of the-methyl glabridin on rhizoctonia solani and fusarium graminearum is equivalent to that of a contrast medicament, namely thiophanate-methyl, and the bacteriostatic activity on botrytis cinerea is superior to that of thiophanate-methyl; the antibacterial activity of the liquiritigenin B on rice blast germs is equivalent to that of thiophanate methyl, and the antibacterial activity on cucumber botrytis cinerea is superior to that of thiophanate methyl.

TABLE 1 bacteriostatic activity of two isoflavonoid compounds on phytopathogens

Example 6:

the control of sclerotinia rot of colza and gray mold of cucumber was determined with 20% isoflavone suspension concentrate prepared as in example 2:

diluting 20% isoflavone suspending agent at 4000 times, 2000 times and 1000 times, spraying onto isolated rape leaf or cucumber leaf with clear water as blank control, and moistening with absorbent cotton. And (3) picking a bacterium dish with the diameter of 5mm from the edges of the bacterial colonies of the vigorous sclerotinia sclerotiorum and the botrytis cinerea, inoculating leaves, culturing at 25 ℃ until the control is fully developed, investigating the condition of the development and calculating the control effect.

The test result shows that: under the treatment of the test agent amount, the medicament with each concentration has no adverse effect on the leaves. The suspension formulated as in example 2 significantly inhibited the development of lesions. 4' -OThe control effect of 1000-time dilution of the methyl glabridin on sclerotinia rot of colza and gray mold of cucumber is above 80%, and the control effect of 1000-time dilution of the liquiritigenin B on sclerotinia rot of colza and gray mold of cucumber is above 50%.

Claims (5)

1. The application of two isoflavone compounds in preventing and treating plant diseases is provided.

2. Isoflavones according to claim 1, characterized by the chemical name: (R) -2- (8, 8-dimethyl-3, 4-dihydro-2H,8HPyrano [2,3- ]f]Benzopyran-3-yl) -5-methoxyphenol and (A)R) -6- (8, 8-dimethyl-3, 4-dihydro-2)H,8HPyrano [2,3- ]f]Benzopyran-3-yl) -2, 2-dimethyl-2H-chromone-5-ol, trivial names 4-O-methyl glabridin and glabridin B, having the following chemical structural formula:

。

3. the use as claimed in claim 1, characterized in that the two isoflavonoids are processed as active ingredients and pesticide adjuvants into any formulation which is acceptable for pesticides.

4. The dosage form of claim 3, wherein the dosage form comprises a powder, a wettable powder, a soluble powder, a granule, an aqueous solution, an emulsifiable concentrate, an aqueous emulsion, a microemulsion, a water dispersible granule, a suspension, a smoke agent, a sustained release agent, a seed coating agent or an oil agent.

5. The use as claimed in claim 1, characterized in that the isoflavonoids are useful for inhibiting sclerotinia sclerotiorum, fusarium graminearum, botrytis cinerea, colletotrichum lycii, rhizoctonia solani, fusarium oxysporum, pyricularia oryzae and fusarium oxysporum; the plant source bactericide prepared by processing the isoflavone compound as an active ingredient can be used for preventing and treating plant diseases caused by the pathogenic bacteria.